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Not Kidding: Yellow Dye 5 May Lead to Invisibility
Applying the dye to lab mice made their skin temporarily transparent, allowing Stanford University researchers to observe the rodents’ digestive system, muscle fibers, and blood vessels, according to a study published in Science.
“It’s a stunning result,” said senior author Guosong Hong, PhD, who is assistant professor of materials science and engineering at Stanford University in California. “If the same technique could be applied to humans, it could offer a variety of benefits in biology, diagnostics, and even cosmetics.”
The work drew upon optical concepts first described in the early 20th century to form a surprising theory: Applying a light-absorbing substance could render skin transparent by reducing the chaotic scattering of light as it strikes proteins, fats, and water in tissue.
A search for a suitable light absorber led to FD&C Yellow 5, also called tartrazine, a synthetic color additive certified by the Food and Drug Administration (FDA) for use in foods, cosmetics, and medications.
Rubbed on live mice (after areas of fur were removed using a drugstore depilatory cream), tartrazine rendered skin on their bellies, hind legs, and heads transparent within 5 minutes. With the naked eye, the researchers watched a mouse’s intestines, bladder, and liver at work. Using a microscope, they observed muscle fibers and saw blood vessels in a living mouse’s brain — all without making incisions. Transparency faded quickly when the dye was washed off.
Someday, the concept could be used in doctors’ offices and hospitals, Dr. Hong said.
“Instead of relying on invasive biopsies, doctors might be able to diagnose deep-seated tumors by simply examining a person’s tissue without the need for invasive surgical removal,” he said. “This technique could potentially make blood draws less painful by helping phlebotomists easily locate veins under the skin. It could also enhance procedures like laser tattoo removal by allowing more precise targeting of the pigment beneath the skin.”
From Cake Frosting to Groundbreaking Research
Yellow 5 food dye can be found in everything from cereal, soda, spices, and cake frosting to lipstick, mouthwash, shampoo, dietary supplements, and house paint. Although it’s in some topical medications, more research is needed before it could be used in human diagnostics, said Christopher J. Rowlands, PhD, a senior lecturer in the Department of Bioengineering at Imperial College London, England, where he studies biophotonic instrumentation — ways to image structures inside the body more quickly and clearly.
But the finding could prove useful in research. In a commentary published in Science, Dr. Rowlands and his colleague Jon Gorecki, PhD, an experimental optical physicist also at Imperial College London, noted that the dye could be an alternative to other optical clearing agents currently used in lab studies, such as glycerol, fructose, or acetic acid. Advantages are the effect is reversible and works at lower concentrations with fewer side effects. This could broaden the types of studies possible in lab animals, so researchers don’t have to rely on naturally transparent creatures like nematodes and zebrafish.
The dye could also be paired with imaging techniques such as MRI or electron microscopy.
“Imaging techniques all have pros and cons,” Dr. Rowlands said. “MRI can see all the way through the body albeit with limited resolution and contrast. Electron microscopy has excellent resolution but limited compatibility with live tissue and penetration depth. Optical microscopy has subcellular resolution, the ability to label things, excellent biocompatibility but less than 1 millimeter of penetration depth. This clearing method will give a substantial boost to optical imaging for medicine and biology.”
The discovery could improve the depth imaging equipment can achieve by tenfold, according to the commentary.
Brain research especially stands to benefit. “Neurobiology in particular will have great use for combinations of multiphoton, optogenetics, and tissue clearing to record and control neural activity over (potentially) the whole mouse brain,” he said.
Refraction, Absorption, and The Invisible Man
The dye discovery has distant echoes in H.G. Wells’ 1897 novel The Invisible Man, Dr. Rowlands noted. In the book, a serum makes the main character invisible by changing the light scattering — or refractive index (RI) — of his cells to match the air around him.
The Stanford engineers looked to the past for inspiration, but not to fiction. They turned to a concept first described in the 1920s called the Kramers-Kronig relations, a mathematical principle that can be applied to relationships between the way light is refracted and absorbed in different materials. They also read up on Lorentz oscillation, which describes how electrons and atoms inside molecules react to light.
They reasoned that light-absorbing compounds could equalize the differences between the light-scattering properties of proteins, lipids, and water that make skin opaque.
With that, the search was on. The study’s first author, postdoctoral researcher Zihao Ou, PhD, began testing strong dyes to find a candidate. Tartrazine was a front-runner.
“We found that dye molecules are more efficient in raising the refractive index of water than conventional RI-matching agents, thus resulting in transparency at a much lower concentration,” Dr. Hong said. “The underlying physics, explained by the Lorentz oscillator model and Kramers-Kronig relations, reveals that conventional RI matching agents like fructose are not as efficient because they are not ‘colored’ enough.”
What’s Next
Though the dye is already in products that people consume and apply to their skin, medical use is years away. In some people, tartrazine can cause skin or respiratory reactions.
The National Science Foundation (NSF), which helped fund the research, posted a home or classroom activity related to the work on its website. It involves painting a tartrazine solution on a thin slice of raw chicken breast, making it transparent. The experiment should only be done while wearing a mask, eye protection, lab coat, and lab-quality nitrile gloves for protection, according to the NSF.
Meanwhile, Dr. Hong said his lab is looking for new compounds that will improve visibility through transparent skin, removing a red tone seen in the current experiments. And they’re looking for ways to induce cells to make their own “see-through” compounds.
“We are exploring methods for cells to express intensely absorbing molecules endogenously, enabling genetically encoded tissue transparency in live animals,” he said.
A version of this article first appeared on Medscape.com.
Applying the dye to lab mice made their skin temporarily transparent, allowing Stanford University researchers to observe the rodents’ digestive system, muscle fibers, and blood vessels, according to a study published in Science.
“It’s a stunning result,” said senior author Guosong Hong, PhD, who is assistant professor of materials science and engineering at Stanford University in California. “If the same technique could be applied to humans, it could offer a variety of benefits in biology, diagnostics, and even cosmetics.”
The work drew upon optical concepts first described in the early 20th century to form a surprising theory: Applying a light-absorbing substance could render skin transparent by reducing the chaotic scattering of light as it strikes proteins, fats, and water in tissue.
A search for a suitable light absorber led to FD&C Yellow 5, also called tartrazine, a synthetic color additive certified by the Food and Drug Administration (FDA) for use in foods, cosmetics, and medications.
Rubbed on live mice (after areas of fur were removed using a drugstore depilatory cream), tartrazine rendered skin on their bellies, hind legs, and heads transparent within 5 minutes. With the naked eye, the researchers watched a mouse’s intestines, bladder, and liver at work. Using a microscope, they observed muscle fibers and saw blood vessels in a living mouse’s brain — all without making incisions. Transparency faded quickly when the dye was washed off.
Someday, the concept could be used in doctors’ offices and hospitals, Dr. Hong said.
“Instead of relying on invasive biopsies, doctors might be able to diagnose deep-seated tumors by simply examining a person’s tissue without the need for invasive surgical removal,” he said. “This technique could potentially make blood draws less painful by helping phlebotomists easily locate veins under the skin. It could also enhance procedures like laser tattoo removal by allowing more precise targeting of the pigment beneath the skin.”
From Cake Frosting to Groundbreaking Research
Yellow 5 food dye can be found in everything from cereal, soda, spices, and cake frosting to lipstick, mouthwash, shampoo, dietary supplements, and house paint. Although it’s in some topical medications, more research is needed before it could be used in human diagnostics, said Christopher J. Rowlands, PhD, a senior lecturer in the Department of Bioengineering at Imperial College London, England, where he studies biophotonic instrumentation — ways to image structures inside the body more quickly and clearly.
But the finding could prove useful in research. In a commentary published in Science, Dr. Rowlands and his colleague Jon Gorecki, PhD, an experimental optical physicist also at Imperial College London, noted that the dye could be an alternative to other optical clearing agents currently used in lab studies, such as glycerol, fructose, or acetic acid. Advantages are the effect is reversible and works at lower concentrations with fewer side effects. This could broaden the types of studies possible in lab animals, so researchers don’t have to rely on naturally transparent creatures like nematodes and zebrafish.
The dye could also be paired with imaging techniques such as MRI or electron microscopy.
“Imaging techniques all have pros and cons,” Dr. Rowlands said. “MRI can see all the way through the body albeit with limited resolution and contrast. Electron microscopy has excellent resolution but limited compatibility with live tissue and penetration depth. Optical microscopy has subcellular resolution, the ability to label things, excellent biocompatibility but less than 1 millimeter of penetration depth. This clearing method will give a substantial boost to optical imaging for medicine and biology.”
The discovery could improve the depth imaging equipment can achieve by tenfold, according to the commentary.
Brain research especially stands to benefit. “Neurobiology in particular will have great use for combinations of multiphoton, optogenetics, and tissue clearing to record and control neural activity over (potentially) the whole mouse brain,” he said.
Refraction, Absorption, and The Invisible Man
The dye discovery has distant echoes in H.G. Wells’ 1897 novel The Invisible Man, Dr. Rowlands noted. In the book, a serum makes the main character invisible by changing the light scattering — or refractive index (RI) — of his cells to match the air around him.
The Stanford engineers looked to the past for inspiration, but not to fiction. They turned to a concept first described in the 1920s called the Kramers-Kronig relations, a mathematical principle that can be applied to relationships between the way light is refracted and absorbed in different materials. They also read up on Lorentz oscillation, which describes how electrons and atoms inside molecules react to light.
They reasoned that light-absorbing compounds could equalize the differences between the light-scattering properties of proteins, lipids, and water that make skin opaque.
With that, the search was on. The study’s first author, postdoctoral researcher Zihao Ou, PhD, began testing strong dyes to find a candidate. Tartrazine was a front-runner.
“We found that dye molecules are more efficient in raising the refractive index of water than conventional RI-matching agents, thus resulting in transparency at a much lower concentration,” Dr. Hong said. “The underlying physics, explained by the Lorentz oscillator model and Kramers-Kronig relations, reveals that conventional RI matching agents like fructose are not as efficient because they are not ‘colored’ enough.”
What’s Next
Though the dye is already in products that people consume and apply to their skin, medical use is years away. In some people, tartrazine can cause skin or respiratory reactions.
The National Science Foundation (NSF), which helped fund the research, posted a home or classroom activity related to the work on its website. It involves painting a tartrazine solution on a thin slice of raw chicken breast, making it transparent. The experiment should only be done while wearing a mask, eye protection, lab coat, and lab-quality nitrile gloves for protection, according to the NSF.
Meanwhile, Dr. Hong said his lab is looking for new compounds that will improve visibility through transparent skin, removing a red tone seen in the current experiments. And they’re looking for ways to induce cells to make their own “see-through” compounds.
“We are exploring methods for cells to express intensely absorbing molecules endogenously, enabling genetically encoded tissue transparency in live animals,” he said.
A version of this article first appeared on Medscape.com.
Applying the dye to lab mice made their skin temporarily transparent, allowing Stanford University researchers to observe the rodents’ digestive system, muscle fibers, and blood vessels, according to a study published in Science.
“It’s a stunning result,” said senior author Guosong Hong, PhD, who is assistant professor of materials science and engineering at Stanford University in California. “If the same technique could be applied to humans, it could offer a variety of benefits in biology, diagnostics, and even cosmetics.”
The work drew upon optical concepts first described in the early 20th century to form a surprising theory: Applying a light-absorbing substance could render skin transparent by reducing the chaotic scattering of light as it strikes proteins, fats, and water in tissue.
A search for a suitable light absorber led to FD&C Yellow 5, also called tartrazine, a synthetic color additive certified by the Food and Drug Administration (FDA) for use in foods, cosmetics, and medications.
Rubbed on live mice (after areas of fur were removed using a drugstore depilatory cream), tartrazine rendered skin on their bellies, hind legs, and heads transparent within 5 minutes. With the naked eye, the researchers watched a mouse’s intestines, bladder, and liver at work. Using a microscope, they observed muscle fibers and saw blood vessels in a living mouse’s brain — all without making incisions. Transparency faded quickly when the dye was washed off.
Someday, the concept could be used in doctors’ offices and hospitals, Dr. Hong said.
“Instead of relying on invasive biopsies, doctors might be able to diagnose deep-seated tumors by simply examining a person’s tissue without the need for invasive surgical removal,” he said. “This technique could potentially make blood draws less painful by helping phlebotomists easily locate veins under the skin. It could also enhance procedures like laser tattoo removal by allowing more precise targeting of the pigment beneath the skin.”
From Cake Frosting to Groundbreaking Research
Yellow 5 food dye can be found in everything from cereal, soda, spices, and cake frosting to lipstick, mouthwash, shampoo, dietary supplements, and house paint. Although it’s in some topical medications, more research is needed before it could be used in human diagnostics, said Christopher J. Rowlands, PhD, a senior lecturer in the Department of Bioengineering at Imperial College London, England, where he studies biophotonic instrumentation — ways to image structures inside the body more quickly and clearly.
But the finding could prove useful in research. In a commentary published in Science, Dr. Rowlands and his colleague Jon Gorecki, PhD, an experimental optical physicist also at Imperial College London, noted that the dye could be an alternative to other optical clearing agents currently used in lab studies, such as glycerol, fructose, or acetic acid. Advantages are the effect is reversible and works at lower concentrations with fewer side effects. This could broaden the types of studies possible in lab animals, so researchers don’t have to rely on naturally transparent creatures like nematodes and zebrafish.
The dye could also be paired with imaging techniques such as MRI or electron microscopy.
“Imaging techniques all have pros and cons,” Dr. Rowlands said. “MRI can see all the way through the body albeit with limited resolution and contrast. Electron microscopy has excellent resolution but limited compatibility with live tissue and penetration depth. Optical microscopy has subcellular resolution, the ability to label things, excellent biocompatibility but less than 1 millimeter of penetration depth. This clearing method will give a substantial boost to optical imaging for medicine and biology.”
The discovery could improve the depth imaging equipment can achieve by tenfold, according to the commentary.
Brain research especially stands to benefit. “Neurobiology in particular will have great use for combinations of multiphoton, optogenetics, and tissue clearing to record and control neural activity over (potentially) the whole mouse brain,” he said.
Refraction, Absorption, and The Invisible Man
The dye discovery has distant echoes in H.G. Wells’ 1897 novel The Invisible Man, Dr. Rowlands noted. In the book, a serum makes the main character invisible by changing the light scattering — or refractive index (RI) — of his cells to match the air around him.
The Stanford engineers looked to the past for inspiration, but not to fiction. They turned to a concept first described in the 1920s called the Kramers-Kronig relations, a mathematical principle that can be applied to relationships between the way light is refracted and absorbed in different materials. They also read up on Lorentz oscillation, which describes how electrons and atoms inside molecules react to light.
They reasoned that light-absorbing compounds could equalize the differences between the light-scattering properties of proteins, lipids, and water that make skin opaque.
With that, the search was on. The study’s first author, postdoctoral researcher Zihao Ou, PhD, began testing strong dyes to find a candidate. Tartrazine was a front-runner.
“We found that dye molecules are more efficient in raising the refractive index of water than conventional RI-matching agents, thus resulting in transparency at a much lower concentration,” Dr. Hong said. “The underlying physics, explained by the Lorentz oscillator model and Kramers-Kronig relations, reveals that conventional RI matching agents like fructose are not as efficient because they are not ‘colored’ enough.”
What’s Next
Though the dye is already in products that people consume and apply to their skin, medical use is years away. In some people, tartrazine can cause skin or respiratory reactions.
The National Science Foundation (NSF), which helped fund the research, posted a home or classroom activity related to the work on its website. It involves painting a tartrazine solution on a thin slice of raw chicken breast, making it transparent. The experiment should only be done while wearing a mask, eye protection, lab coat, and lab-quality nitrile gloves for protection, according to the NSF.
Meanwhile, Dr. Hong said his lab is looking for new compounds that will improve visibility through transparent skin, removing a red tone seen in the current experiments. And they’re looking for ways to induce cells to make their own “see-through” compounds.
“We are exploring methods for cells to express intensely absorbing molecules endogenously, enabling genetically encoded tissue transparency in live animals,” he said.
A version of this article first appeared on Medscape.com.
FROM SCIENCE
The New Formula for Stronger, Longer-Lasting Vaccines
Vaccines work pretty well. But with a little help, they could work better.
Stanford researchers have developed a new vaccine helper that combines two kinds of adjuvants, ingredients that improve a vaccine’s efficacy, in a novel, customizable system.
In lab tests, the experimental additive improved the effectiveness of COVID-19 and HIV vaccine candidates, though it could be adapted to stimulate immune responses to a variety of pathogens, the researchers said. It could also be used one day to fine-tune vaccines for vulnerable groups like young children, older adults, and those with compromised immune systems.
“Current vaccines are not perfect,” said lead study author Ben Ou, a PhD candidate and researcher in the lab of Eric Appel, PhD, an associate professor of materials science and engineering, at Stanford University in California. “Many fail to generate long-lasting immunity or immunity against closely related strains [such as] flu or COVID vaccines. One way to improve them is to design more potent vaccine adjuvants.”
The study marks an advance in an area of growing scientific interest: Combining different adjuvants to enhance the immune-stimulating effect.
The Stanford scientists developed sphere-shaped nanoparticles, like tiny round cages, made of saponins, immune-stimulating molecules common in adjuvant development. To these nanoparticles, they attached Toll-like receptor (TLR) agonists, molecules that have become a focus in vaccine research because they stimulate a variety of immune responses.
Dr. Ou and the team tested the new adjuvant platform in COVID and HIV vaccines, comparing it to vaccines containing alum, a widely used adjuvant. (Alum is not used in COVID vaccines available in the United States.)
The nanoparticle-adjuvanted vaccines triggered stronger, longer-lasting effects.
Notably, the combination of the new adjuvant system with a SARS-CoV-2 virus vaccine was effective in mice against the original SARS-CoV-2 virus and against Delta, Omicron, and other variants that emerged in the months and years after the initial outbreak.
“Since our nanoparticle adjuvant platform is more potent than traditional/clinical vaccine adjuvants,” Dr. Ou said, “we expected mice to produce broadly neutralizing antibodies and better breadth responses.”
100 Years of Adjuvants
The first vaccine adjuvants were aluminum salts mixed into shots against pertussis, diphtheria, and tetanus in the 1920s. Today, alum is still used in many vaccines, including shots for diphtheria, tetanus, and pertussis; hepatitis A and B; human papillomavirus; and pneumococcal disease.
But since the 1990s, new adjuvants have come on the scene. Saponin-based compounds, harvested from the soapbark tree, are used in the Novavax COVID-19 Vaccine, Adjuvanted; a synthetic DNA adjuvant in the Heplisav-B vaccine against hepatitis B; and oil in water adjuvants using squalene in the Fluad and Fluad Quadrivalent influenza vaccines. Other vaccines, including those for chickenpox, cholera, measles, mumps, rubella, and mRNA-based COVID vaccines from Pfizer-BioNTech and Moderna, don’t contain adjuvants.
TLR agonists have recently become research hotspots in vaccine science.
“TLR agonists activate the innate immune system, putting it on a heightened alert state that can result in a higher antibody production and longer-lasting protection,” said David Burkhart, PhD, a research professor in biomedical and pharmaceutical sciences at the University of Montana in Missoula. He is also the chief operating officer of Inimmune, a biotech company developing vaccines and immunotherapies.
Dr. Burkhart studies TLR agonists in vaccines and other applications. “Different combinations activate different parts of the immune system,” he said. “TLR4 might activate the army, while TLR7 might activate the air force. You might need both in one vaccine.”
TLR agonists have also shown promise against Alzheimer’s disease, allergies, cancer, and even addiction. In immune’s experimental immunotherapy using TLR agonists for advanced solid tumors has just entered human trials, and the company is looking at a TLR agonist therapy for allergic rhinitis.
Combining Forces
In the new study, researchers tested five different combinations of TLR agonists hooked to the saponin nanoparticle framework. Each elicited a slightly different response from the immune cells.
“Our immune systems generate different downstream immune responses based on which TLRs are activated,” Dr. Ou said.
Ultimately, the advance could spur the development of vaccines tuned for stronger immune protection.
“We need different immune responses to fight different types of pathogens,” Dr. Ou said. “Depending on what specific virus/disease the vaccine is formulated for, activation of one specific TLR may confer better protection than another TLR.”
According to Dr. Burkhart, combining a saponin with a TLR agonist has found success before.
Biopharma company GSK (formerly GlaxoSmithKline) used the combination in its AS01 adjuvant, in the vaccine Shingrix against herpes zoster. The live-attenuated yellow fever vaccine, given to more than 600 million people around the world and considered one of the most powerful vaccines ever developed, uses several TLR agonists.
The Stanford paper, Dr. Burkhart said, “is a nice demonstration of the enhanced efficacy [that] adjuvants can provide to vaccines by exploiting the synergy different adjuvants and TLR agonists can provide when used in combination.”
Tailoring Vaccines
The customizable aspect of TLR agonists is important too, Dr. Burkhart said.
“The human immune system changes dramatically from birth to childhood into adulthood into older maturity,” he said. “It’s not a one-size-fits-all. Vaccines need to be tailored to these populations for maximum effectiveness and safety. TLRAs [TLR agonists] are a highly valuable tool in the vaccine toolbox. I think it’s inevitable we’ll have more in the future.”
That’s what the Stanford researchers hope for.
They noted in the study that the nanoparticle platform could easily be used to test different TLR agonist adjuvant combinations in vaccines.
But human studies are still a ways off. Tests in larger animals would likely come next, Dr. Ou said.
“We now have a single nanoparticle adjuvant platform with formulations containing different TLRs,” Dr. Ou said. “Scientists can pick which specific formulation is the most suitable for their needs.”
A version of this article first appeared on Medscape.com.
Vaccines work pretty well. But with a little help, they could work better.
Stanford researchers have developed a new vaccine helper that combines two kinds of adjuvants, ingredients that improve a vaccine’s efficacy, in a novel, customizable system.
In lab tests, the experimental additive improved the effectiveness of COVID-19 and HIV vaccine candidates, though it could be adapted to stimulate immune responses to a variety of pathogens, the researchers said. It could also be used one day to fine-tune vaccines for vulnerable groups like young children, older adults, and those with compromised immune systems.
“Current vaccines are not perfect,” said lead study author Ben Ou, a PhD candidate and researcher in the lab of Eric Appel, PhD, an associate professor of materials science and engineering, at Stanford University in California. “Many fail to generate long-lasting immunity or immunity against closely related strains [such as] flu or COVID vaccines. One way to improve them is to design more potent vaccine adjuvants.”
The study marks an advance in an area of growing scientific interest: Combining different adjuvants to enhance the immune-stimulating effect.
The Stanford scientists developed sphere-shaped nanoparticles, like tiny round cages, made of saponins, immune-stimulating molecules common in adjuvant development. To these nanoparticles, they attached Toll-like receptor (TLR) agonists, molecules that have become a focus in vaccine research because they stimulate a variety of immune responses.
Dr. Ou and the team tested the new adjuvant platform in COVID and HIV vaccines, comparing it to vaccines containing alum, a widely used adjuvant. (Alum is not used in COVID vaccines available in the United States.)
The nanoparticle-adjuvanted vaccines triggered stronger, longer-lasting effects.
Notably, the combination of the new adjuvant system with a SARS-CoV-2 virus vaccine was effective in mice against the original SARS-CoV-2 virus and against Delta, Omicron, and other variants that emerged in the months and years after the initial outbreak.
“Since our nanoparticle adjuvant platform is more potent than traditional/clinical vaccine adjuvants,” Dr. Ou said, “we expected mice to produce broadly neutralizing antibodies and better breadth responses.”
100 Years of Adjuvants
The first vaccine adjuvants were aluminum salts mixed into shots against pertussis, diphtheria, and tetanus in the 1920s. Today, alum is still used in many vaccines, including shots for diphtheria, tetanus, and pertussis; hepatitis A and B; human papillomavirus; and pneumococcal disease.
But since the 1990s, new adjuvants have come on the scene. Saponin-based compounds, harvested from the soapbark tree, are used in the Novavax COVID-19 Vaccine, Adjuvanted; a synthetic DNA adjuvant in the Heplisav-B vaccine against hepatitis B; and oil in water adjuvants using squalene in the Fluad and Fluad Quadrivalent influenza vaccines. Other vaccines, including those for chickenpox, cholera, measles, mumps, rubella, and mRNA-based COVID vaccines from Pfizer-BioNTech and Moderna, don’t contain adjuvants.
TLR agonists have recently become research hotspots in vaccine science.
“TLR agonists activate the innate immune system, putting it on a heightened alert state that can result in a higher antibody production and longer-lasting protection,” said David Burkhart, PhD, a research professor in biomedical and pharmaceutical sciences at the University of Montana in Missoula. He is also the chief operating officer of Inimmune, a biotech company developing vaccines and immunotherapies.
Dr. Burkhart studies TLR agonists in vaccines and other applications. “Different combinations activate different parts of the immune system,” he said. “TLR4 might activate the army, while TLR7 might activate the air force. You might need both in one vaccine.”
TLR agonists have also shown promise against Alzheimer’s disease, allergies, cancer, and even addiction. In immune’s experimental immunotherapy using TLR agonists for advanced solid tumors has just entered human trials, and the company is looking at a TLR agonist therapy for allergic rhinitis.
Combining Forces
In the new study, researchers tested five different combinations of TLR agonists hooked to the saponin nanoparticle framework. Each elicited a slightly different response from the immune cells.
“Our immune systems generate different downstream immune responses based on which TLRs are activated,” Dr. Ou said.
Ultimately, the advance could spur the development of vaccines tuned for stronger immune protection.
“We need different immune responses to fight different types of pathogens,” Dr. Ou said. “Depending on what specific virus/disease the vaccine is formulated for, activation of one specific TLR may confer better protection than another TLR.”
According to Dr. Burkhart, combining a saponin with a TLR agonist has found success before.
Biopharma company GSK (formerly GlaxoSmithKline) used the combination in its AS01 adjuvant, in the vaccine Shingrix against herpes zoster. The live-attenuated yellow fever vaccine, given to more than 600 million people around the world and considered one of the most powerful vaccines ever developed, uses several TLR agonists.
The Stanford paper, Dr. Burkhart said, “is a nice demonstration of the enhanced efficacy [that] adjuvants can provide to vaccines by exploiting the synergy different adjuvants and TLR agonists can provide when used in combination.”
Tailoring Vaccines
The customizable aspect of TLR agonists is important too, Dr. Burkhart said.
“The human immune system changes dramatically from birth to childhood into adulthood into older maturity,” he said. “It’s not a one-size-fits-all. Vaccines need to be tailored to these populations for maximum effectiveness and safety. TLRAs [TLR agonists] are a highly valuable tool in the vaccine toolbox. I think it’s inevitable we’ll have more in the future.”
That’s what the Stanford researchers hope for.
They noted in the study that the nanoparticle platform could easily be used to test different TLR agonist adjuvant combinations in vaccines.
But human studies are still a ways off. Tests in larger animals would likely come next, Dr. Ou said.
“We now have a single nanoparticle adjuvant platform with formulations containing different TLRs,” Dr. Ou said. “Scientists can pick which specific formulation is the most suitable for their needs.”
A version of this article first appeared on Medscape.com.
Vaccines work pretty well. But with a little help, they could work better.
Stanford researchers have developed a new vaccine helper that combines two kinds of adjuvants, ingredients that improve a vaccine’s efficacy, in a novel, customizable system.
In lab tests, the experimental additive improved the effectiveness of COVID-19 and HIV vaccine candidates, though it could be adapted to stimulate immune responses to a variety of pathogens, the researchers said. It could also be used one day to fine-tune vaccines for vulnerable groups like young children, older adults, and those with compromised immune systems.
“Current vaccines are not perfect,” said lead study author Ben Ou, a PhD candidate and researcher in the lab of Eric Appel, PhD, an associate professor of materials science and engineering, at Stanford University in California. “Many fail to generate long-lasting immunity or immunity against closely related strains [such as] flu or COVID vaccines. One way to improve them is to design more potent vaccine adjuvants.”
The study marks an advance in an area of growing scientific interest: Combining different adjuvants to enhance the immune-stimulating effect.
The Stanford scientists developed sphere-shaped nanoparticles, like tiny round cages, made of saponins, immune-stimulating molecules common in adjuvant development. To these nanoparticles, they attached Toll-like receptor (TLR) agonists, molecules that have become a focus in vaccine research because they stimulate a variety of immune responses.
Dr. Ou and the team tested the new adjuvant platform in COVID and HIV vaccines, comparing it to vaccines containing alum, a widely used adjuvant. (Alum is not used in COVID vaccines available in the United States.)
The nanoparticle-adjuvanted vaccines triggered stronger, longer-lasting effects.
Notably, the combination of the new adjuvant system with a SARS-CoV-2 virus vaccine was effective in mice against the original SARS-CoV-2 virus and against Delta, Omicron, and other variants that emerged in the months and years after the initial outbreak.
“Since our nanoparticle adjuvant platform is more potent than traditional/clinical vaccine adjuvants,” Dr. Ou said, “we expected mice to produce broadly neutralizing antibodies and better breadth responses.”
100 Years of Adjuvants
The first vaccine adjuvants were aluminum salts mixed into shots against pertussis, diphtheria, and tetanus in the 1920s. Today, alum is still used in many vaccines, including shots for diphtheria, tetanus, and pertussis; hepatitis A and B; human papillomavirus; and pneumococcal disease.
But since the 1990s, new adjuvants have come on the scene. Saponin-based compounds, harvested from the soapbark tree, are used in the Novavax COVID-19 Vaccine, Adjuvanted; a synthetic DNA adjuvant in the Heplisav-B vaccine against hepatitis B; and oil in water adjuvants using squalene in the Fluad and Fluad Quadrivalent influenza vaccines. Other vaccines, including those for chickenpox, cholera, measles, mumps, rubella, and mRNA-based COVID vaccines from Pfizer-BioNTech and Moderna, don’t contain adjuvants.
TLR agonists have recently become research hotspots in vaccine science.
“TLR agonists activate the innate immune system, putting it on a heightened alert state that can result in a higher antibody production and longer-lasting protection,” said David Burkhart, PhD, a research professor in biomedical and pharmaceutical sciences at the University of Montana in Missoula. He is also the chief operating officer of Inimmune, a biotech company developing vaccines and immunotherapies.
Dr. Burkhart studies TLR agonists in vaccines and other applications. “Different combinations activate different parts of the immune system,” he said. “TLR4 might activate the army, while TLR7 might activate the air force. You might need both in one vaccine.”
TLR agonists have also shown promise against Alzheimer’s disease, allergies, cancer, and even addiction. In immune’s experimental immunotherapy using TLR agonists for advanced solid tumors has just entered human trials, and the company is looking at a TLR agonist therapy for allergic rhinitis.
Combining Forces
In the new study, researchers tested five different combinations of TLR agonists hooked to the saponin nanoparticle framework. Each elicited a slightly different response from the immune cells.
“Our immune systems generate different downstream immune responses based on which TLRs are activated,” Dr. Ou said.
Ultimately, the advance could spur the development of vaccines tuned for stronger immune protection.
“We need different immune responses to fight different types of pathogens,” Dr. Ou said. “Depending on what specific virus/disease the vaccine is formulated for, activation of one specific TLR may confer better protection than another TLR.”
According to Dr. Burkhart, combining a saponin with a TLR agonist has found success before.
Biopharma company GSK (formerly GlaxoSmithKline) used the combination in its AS01 adjuvant, in the vaccine Shingrix against herpes zoster. The live-attenuated yellow fever vaccine, given to more than 600 million people around the world and considered one of the most powerful vaccines ever developed, uses several TLR agonists.
The Stanford paper, Dr. Burkhart said, “is a nice demonstration of the enhanced efficacy [that] adjuvants can provide to vaccines by exploiting the synergy different adjuvants and TLR agonists can provide when used in combination.”
Tailoring Vaccines
The customizable aspect of TLR agonists is important too, Dr. Burkhart said.
“The human immune system changes dramatically from birth to childhood into adulthood into older maturity,” he said. “It’s not a one-size-fits-all. Vaccines need to be tailored to these populations for maximum effectiveness and safety. TLRAs [TLR agonists] are a highly valuable tool in the vaccine toolbox. I think it’s inevitable we’ll have more in the future.”
That’s what the Stanford researchers hope for.
They noted in the study that the nanoparticle platform could easily be used to test different TLR agonist adjuvant combinations in vaccines.
But human studies are still a ways off. Tests in larger animals would likely come next, Dr. Ou said.
“We now have a single nanoparticle adjuvant platform with formulations containing different TLRs,” Dr. Ou said. “Scientists can pick which specific formulation is the most suitable for their needs.”
A version of this article first appeared on Medscape.com.
FROM SCIENCE ADVANCES
Light Therapy, Phototherapy, Photobiomodulation: New Ways to Heal With Light
A surprising therapy is showing promise for chronic pain, vision loss, and muscle recovery, among other conditions.
It’s not a pill, an injection, or surgery.
It’s light.
Yes, light. The thing that appears when you open the curtains, flip a switch, or strike a match.
Light illuminates our world and helps us see. Early human trials suggest it may help us heal in new ways as well.
“Phototherapy is still in its infancy,” said Mohab Ibrahim, MD, PhD, a professor of anesthesiology at the University of Arizona, Tucson, who studies the effects of light on chronic pain. “There are so many questions, a lot of things we do not understand yet. But that’s where it gets interesting. What we can conclude is that different colors of light can influence different biological functions.”
This growing field goes by several names. Light therapy. Phototherapy. Photobiomodulation.
It leverages known effects of light on human health — such as skin exposure to ultraviolet light producing vitamin D or blue light’s power to regulate human body clocks — to take light as medicine in surprising new directions.
New Science, Old Idea
The science is young, but the concept of using light to restore health is thousands of years old.
Hippocrates prescribed sunbathing to patients at his medical center on the Greek island of Kos in 400 BC. Florence Nightingale promoted sunshine, along with fresh air, as prerequisites for recovery in hospitals during the Civil War. A Danish doctor, Niels Finsen, won the Nobel Prize in 1903 for developing ultraviolet lamps to treat a tuberculosis-related skin condition. And worried parents of the 1930s sat their babies in front of mercury arc lamps, bought at the drugstore, to discourage rickets.
Today, light therapy is widely used in medicine for newborn jaundice, psoriasis, and seasonal affective disorder and in light-activated treatments for cancers of the esophagus and lungs, as well as for actinic keratosis, a skin condition that can lead to cancer.
But researchers are finding that light may be capable of far more, particularly in conditions with few treatment options or where available drugs have unwanted side effects.
How Red Light Could Restore Vision
When 100 midlife and older adults, aged 53-91, with the dry form of age-related macular degeneration (AMD) were treated with an experimental red-light therapy or a sham therapy, the light treatment group showed signs of improved vision, as measured on a standard eye chart.
Volunteers received the therapy three times a week for 3-5 weeks, every 4 months for 2 years. By the study’s end, 67% of those treated with light could read an additional five letters on the chart, and 20% could read 10 or more. About 7% developed geographic atrophy — the most advanced, vision-threatening stage of dry AMD — compared with 24% in the sham group.
The study, called LIGHTSITE III, was conducted at 10 ophthalmology centers across the United States. The device they used — the Valeda Light Delivery System from medical device company LumiThera — is available in Europe and now being reviewed by the Food and Drug Administration (FDA).
Exposure to red light at the wavelengths used in the study likely revitalizes failing mitochondria — the power plants inside cells — so they produce more energy, the researchers say.
“This is the first therapy for dry AMD that’s actually shown a benefit in improving vision,” said study coauthor Richard Rosen, MD, chair of ophthalmology at the Icahn School of Medicine at Mount Sinai and chief of Retinal Services at the New York Eye and Ear Infirmary in New York City. “Supplements called AREDS can reduce progression, and in wet AMD we can improve vision loss with injections. But in dry AMD, none of the treatments studied in the past have improved it.”
AMD develops when the eyes can’t break down natural by-products, which glom together as clumps of protein called drusen. Drusen can lodge under the retina, eventually damaging tissue.
“Retinal epithelial cells, a single layer of cells that cares for the photoreceptors in the eyes, are there for life,” Dr. Rosen said. “They have a tremendous capacity to repair themselves, but things [such as aging and smoking] get in the way.”
“I’m proposing,” Dr. Rosen said, “that by boosting energy levels in cells [with red light], we’re improving normal repair mechanisms.”
Lab studies support this idea.
In a 2017 mouse study from the University College London Institute of Ophthalmology in England, retinal function improved by 25% in old mice exposed to red light. And a 2019 study from the Ophthalmological Research Foundation, Oviedo, Spain, found that exposure to blue light harmed the mitochondria in retina cells, while red light somewhat counteracted the losses.
If cleared by the FDA — which the company anticipated could happen in 2024 — LumiThera’s light delivery device will likely be most useful in the beginning stages of dry AMD, Dr. Rosen said. “I think treatment of early dry AMD will be huge.”
Eventually, light therapy may also be valuable in treating or managing glaucoma and diabetic retinopathy.
For now, Dr. Rosen recommended that clinicians and consumers with AMD skip over-the-counter (OTC) red-light therapy devices currently on the market.
“We don’t know what kind of light the devices produce,” he said. “The wavelengths can vary. The eyes are delicate. Experimenting on your own may be hazardous to your vision.”
Green Light for Pain Relief
On his way to the pharmacy to pick up pain relievers for a headache, Dr. Ibrahim passed Gene C. Reid Park in Tucson. Recalling how his brother eased headaches by sitting in his backyard, Dr. Ibrahim pulled over.
“Reid Park is probably one of the greenest areas of Tucson,” said Dr. Ibrahim, who also serves as medical director of the Comprehensive Center for Pain & Addiction at Banner-University Medical Center Phoenix in Arizona. “I spent a half hour or 40 minutes there, and my headache felt better.”
Being outdoors in a green space may be soothing for lots of reasons, like the quiet or the fresh air. But there’s also sunlight reflected off and shining through greenery. The experience inspired Dr. Ibrahim to take a closer look at the effects of green light on chronic pain.
In his 2021 study of 29 people with migraines, participants reported that, after daily exposure to green light for 10 weeks, the number of days per month when they had headaches fell from 7.9 to 2.4 for those who had episodic migraines and from 22.3 to 9.4 for those with chronic migraines. In another 2021 study, 21 people with fibromyalgia who had green light therapy for 10 weeks said their average, self-reported pain intensity fell from 8.4 to 4.9 on a 10-point scale used at the University of Arizona’s pain clinic.
Volunteers in both studies got their light therapy at home, switching on green LED lights while they listened to music, read a book, relaxed, or exercised for 1 or 2 hours daily. The lights were within their field of vision, but they did not look directly at them.
Dr. Ibrahim now has funding from the Department of Defense and Department of Veterans Affairs to find out why green light alters pain perception.
“What we know is that the visual system is connected to certain areas of the brain that also modulate pain,” he said. “We are trying to understand the connection.”
Padma Gulur, MD, a professor of anesthesiology and population health and director of Pain Management Strategy and Opioid Surveillance at Duke University, Durham, North Carolina, saw similar results in a 2023 study of 45 people with fibromyalgia. But instead of using a light source, volunteers wore glasses with clear, green, or blue lenses for 4 hours a day.
After 2 weeks, 33% in the green lens group reduced their use of opioids by 10% or more, compared with 11% in the blue lens group and 8% who wore clear lenses. Previous studies have found green light affects levels of the feel-good brain chemical serotonin and stimulates the body’s own opioid system, the authors noted.
“Green light helps your body control and reduce pain,” Dr. Gulur said. It “seems to help with pain relief by affecting the body’s natural pain management system. This effect appears to play a crucial role in antinociception — reducing the sensation of pain; antiallodynia — preventing normal, nonpainful stimuli from causing pain; and antihyperalgesia — reducing heightened sensitivity to pain.”
Light therapy could help pain patients reduce their dose of opioids or even forgo the drugs altogether, Dr. Gulur said. “It is our hope this will become a useful adjuvant therapy to manage pain.”
In the University of Arizona studies, some patients on green-light therapy stopped their medications completely. Even if they didn’t, other benefits appeared. “They had improved quality of life, decreased depression and anxiety, and improved sleep,” Dr. Ibrahim said.
But not just any green light or green-tinted glasses will work, both researchers said. “We have found there are specific frequencies of green light that give this benefit,” Dr. Gulur said. “OTC products may not be helpful for that reason.”
While Dr. Ibrahim said it could be possible for healthcare practitioners and consumers to consult his studies and put together an inexpensive green-light device at home while carefully following the protocol participants used in the studies , it would first be a good idea for patients to talk with their family doctor or a pain specialist.
“A headache is not always just a headache,” Dr. Ibrahim said. “It could be some other abnormality that needs diagnosis and treatment. If you have long-lasting pain or pain that’s getting worse, it’s always better to discuss it with your physician.”
Helping Muscles Recover With Red Light
Intense exercise — whether it’s a sprint at the end of a morning run, an extra set of biceps curls, or a weekend of all-day DIY home improvement projects — can temporarily damage muscle, causing soreness, inflammation, and even swelling. Phototherapy with red and near-infrared light is widely used by sports trainers, physical therapists, and athletes to aid in recovery. It may even work better than a trendy plunge in an ice bath, according to a 2019 Texas State University review.
But how does it work? Jamie Ghigiarelli, PhD, professor of Allied Health & Kinesiology at Hofstra University in Hempstead, New York, looked closely at signs of inflammation and muscle damage in 12 athletes to find out.
Study participants overtaxed their muscles with rounds of chin-ups, high-speed sprints, and repeated bench presses. Afterward, they relaxed in a full-body red-light therapy bed or in a similar bed without lights.
The results, published in 2020, showed that blood levels of creatine kinase — an enzyme that’s elevated by muscle damage — were 18% lower 1-3 days after exercising for the light-bed group than for the control group.
“Photobiomodulation seems to help with muscle recovery,” Dr. Ghigiarelli said.
Red light at wavelengths from 650 to 820 nm can enter muscle cells, where it is absorbed by mitochondria and boosts their energy production, he said. At the time of his research, some exercise science researchers and athletes thought using light therapy before an event might also increase athletic performance, but according to Dr. Ghigiarelli, that use has not panned out.
Handheld red light and near-infrared light devices for muscle recovery are widely available, but it’s important to do your homework before buying one.
“You want to choose a device with the right energy production — the right wavelength of light, the right power — to be safe and effective,” he said.
For details, he recommends consulting a 2019 paper in The Brazilian Journal of Physical Therapy called “Clinical and scientific recommendations for the use of photobiomodulation therapy in exercise performance enhancement and post-exercise recovery: Current evidence and future directions.”
The paper, from the Laboratory of Phototherapy and Innovative Technologies in Health at the Universidade Nove de Julho in Sao Paulo, Brazil, recommends that for small muscle groups like the biceps or triceps, use red-light lasers or LED devices with a wavelength of 640 nm for red light or 950 nm for infrared light, at a power of 50-200 mW per diode for single-probe device types, at a dose of 20-60 J, given 5-10 minutes after exercise.
A version of this article appeared on Medscape.com.
A surprising therapy is showing promise for chronic pain, vision loss, and muscle recovery, among other conditions.
It’s not a pill, an injection, or surgery.
It’s light.
Yes, light. The thing that appears when you open the curtains, flip a switch, or strike a match.
Light illuminates our world and helps us see. Early human trials suggest it may help us heal in new ways as well.
“Phototherapy is still in its infancy,” said Mohab Ibrahim, MD, PhD, a professor of anesthesiology at the University of Arizona, Tucson, who studies the effects of light on chronic pain. “There are so many questions, a lot of things we do not understand yet. But that’s where it gets interesting. What we can conclude is that different colors of light can influence different biological functions.”
This growing field goes by several names. Light therapy. Phototherapy. Photobiomodulation.
It leverages known effects of light on human health — such as skin exposure to ultraviolet light producing vitamin D or blue light’s power to regulate human body clocks — to take light as medicine in surprising new directions.
New Science, Old Idea
The science is young, but the concept of using light to restore health is thousands of years old.
Hippocrates prescribed sunbathing to patients at his medical center on the Greek island of Kos in 400 BC. Florence Nightingale promoted sunshine, along with fresh air, as prerequisites for recovery in hospitals during the Civil War. A Danish doctor, Niels Finsen, won the Nobel Prize in 1903 for developing ultraviolet lamps to treat a tuberculosis-related skin condition. And worried parents of the 1930s sat their babies in front of mercury arc lamps, bought at the drugstore, to discourage rickets.
Today, light therapy is widely used in medicine for newborn jaundice, psoriasis, and seasonal affective disorder and in light-activated treatments for cancers of the esophagus and lungs, as well as for actinic keratosis, a skin condition that can lead to cancer.
But researchers are finding that light may be capable of far more, particularly in conditions with few treatment options or where available drugs have unwanted side effects.
How Red Light Could Restore Vision
When 100 midlife and older adults, aged 53-91, with the dry form of age-related macular degeneration (AMD) were treated with an experimental red-light therapy or a sham therapy, the light treatment group showed signs of improved vision, as measured on a standard eye chart.
Volunteers received the therapy three times a week for 3-5 weeks, every 4 months for 2 years. By the study’s end, 67% of those treated with light could read an additional five letters on the chart, and 20% could read 10 or more. About 7% developed geographic atrophy — the most advanced, vision-threatening stage of dry AMD — compared with 24% in the sham group.
The study, called LIGHTSITE III, was conducted at 10 ophthalmology centers across the United States. The device they used — the Valeda Light Delivery System from medical device company LumiThera — is available in Europe and now being reviewed by the Food and Drug Administration (FDA).
Exposure to red light at the wavelengths used in the study likely revitalizes failing mitochondria — the power plants inside cells — so they produce more energy, the researchers say.
“This is the first therapy for dry AMD that’s actually shown a benefit in improving vision,” said study coauthor Richard Rosen, MD, chair of ophthalmology at the Icahn School of Medicine at Mount Sinai and chief of Retinal Services at the New York Eye and Ear Infirmary in New York City. “Supplements called AREDS can reduce progression, and in wet AMD we can improve vision loss with injections. But in dry AMD, none of the treatments studied in the past have improved it.”
AMD develops when the eyes can’t break down natural by-products, which glom together as clumps of protein called drusen. Drusen can lodge under the retina, eventually damaging tissue.
“Retinal epithelial cells, a single layer of cells that cares for the photoreceptors in the eyes, are there for life,” Dr. Rosen said. “They have a tremendous capacity to repair themselves, but things [such as aging and smoking] get in the way.”
“I’m proposing,” Dr. Rosen said, “that by boosting energy levels in cells [with red light], we’re improving normal repair mechanisms.”
Lab studies support this idea.
In a 2017 mouse study from the University College London Institute of Ophthalmology in England, retinal function improved by 25% in old mice exposed to red light. And a 2019 study from the Ophthalmological Research Foundation, Oviedo, Spain, found that exposure to blue light harmed the mitochondria in retina cells, while red light somewhat counteracted the losses.
If cleared by the FDA — which the company anticipated could happen in 2024 — LumiThera’s light delivery device will likely be most useful in the beginning stages of dry AMD, Dr. Rosen said. “I think treatment of early dry AMD will be huge.”
Eventually, light therapy may also be valuable in treating or managing glaucoma and diabetic retinopathy.
For now, Dr. Rosen recommended that clinicians and consumers with AMD skip over-the-counter (OTC) red-light therapy devices currently on the market.
“We don’t know what kind of light the devices produce,” he said. “The wavelengths can vary. The eyes are delicate. Experimenting on your own may be hazardous to your vision.”
Green Light for Pain Relief
On his way to the pharmacy to pick up pain relievers for a headache, Dr. Ibrahim passed Gene C. Reid Park in Tucson. Recalling how his brother eased headaches by sitting in his backyard, Dr. Ibrahim pulled over.
“Reid Park is probably one of the greenest areas of Tucson,” said Dr. Ibrahim, who also serves as medical director of the Comprehensive Center for Pain & Addiction at Banner-University Medical Center Phoenix in Arizona. “I spent a half hour or 40 minutes there, and my headache felt better.”
Being outdoors in a green space may be soothing for lots of reasons, like the quiet or the fresh air. But there’s also sunlight reflected off and shining through greenery. The experience inspired Dr. Ibrahim to take a closer look at the effects of green light on chronic pain.
In his 2021 study of 29 people with migraines, participants reported that, after daily exposure to green light for 10 weeks, the number of days per month when they had headaches fell from 7.9 to 2.4 for those who had episodic migraines and from 22.3 to 9.4 for those with chronic migraines. In another 2021 study, 21 people with fibromyalgia who had green light therapy for 10 weeks said their average, self-reported pain intensity fell from 8.4 to 4.9 on a 10-point scale used at the University of Arizona’s pain clinic.
Volunteers in both studies got their light therapy at home, switching on green LED lights while they listened to music, read a book, relaxed, or exercised for 1 or 2 hours daily. The lights were within their field of vision, but they did not look directly at them.
Dr. Ibrahim now has funding from the Department of Defense and Department of Veterans Affairs to find out why green light alters pain perception.
“What we know is that the visual system is connected to certain areas of the brain that also modulate pain,” he said. “We are trying to understand the connection.”
Padma Gulur, MD, a professor of anesthesiology and population health and director of Pain Management Strategy and Opioid Surveillance at Duke University, Durham, North Carolina, saw similar results in a 2023 study of 45 people with fibromyalgia. But instead of using a light source, volunteers wore glasses with clear, green, or blue lenses for 4 hours a day.
After 2 weeks, 33% in the green lens group reduced their use of opioids by 10% or more, compared with 11% in the blue lens group and 8% who wore clear lenses. Previous studies have found green light affects levels of the feel-good brain chemical serotonin and stimulates the body’s own opioid system, the authors noted.
“Green light helps your body control and reduce pain,” Dr. Gulur said. It “seems to help with pain relief by affecting the body’s natural pain management system. This effect appears to play a crucial role in antinociception — reducing the sensation of pain; antiallodynia — preventing normal, nonpainful stimuli from causing pain; and antihyperalgesia — reducing heightened sensitivity to pain.”
Light therapy could help pain patients reduce their dose of opioids or even forgo the drugs altogether, Dr. Gulur said. “It is our hope this will become a useful adjuvant therapy to manage pain.”
In the University of Arizona studies, some patients on green-light therapy stopped their medications completely. Even if they didn’t, other benefits appeared. “They had improved quality of life, decreased depression and anxiety, and improved sleep,” Dr. Ibrahim said.
But not just any green light or green-tinted glasses will work, both researchers said. “We have found there are specific frequencies of green light that give this benefit,” Dr. Gulur said. “OTC products may not be helpful for that reason.”
While Dr. Ibrahim said it could be possible for healthcare practitioners and consumers to consult his studies and put together an inexpensive green-light device at home while carefully following the protocol participants used in the studies , it would first be a good idea for patients to talk with their family doctor or a pain specialist.
“A headache is not always just a headache,” Dr. Ibrahim said. “It could be some other abnormality that needs diagnosis and treatment. If you have long-lasting pain or pain that’s getting worse, it’s always better to discuss it with your physician.”
Helping Muscles Recover With Red Light
Intense exercise — whether it’s a sprint at the end of a morning run, an extra set of biceps curls, or a weekend of all-day DIY home improvement projects — can temporarily damage muscle, causing soreness, inflammation, and even swelling. Phototherapy with red and near-infrared light is widely used by sports trainers, physical therapists, and athletes to aid in recovery. It may even work better than a trendy plunge in an ice bath, according to a 2019 Texas State University review.
But how does it work? Jamie Ghigiarelli, PhD, professor of Allied Health & Kinesiology at Hofstra University in Hempstead, New York, looked closely at signs of inflammation and muscle damage in 12 athletes to find out.
Study participants overtaxed their muscles with rounds of chin-ups, high-speed sprints, and repeated bench presses. Afterward, they relaxed in a full-body red-light therapy bed or in a similar bed without lights.
The results, published in 2020, showed that blood levels of creatine kinase — an enzyme that’s elevated by muscle damage — were 18% lower 1-3 days after exercising for the light-bed group than for the control group.
“Photobiomodulation seems to help with muscle recovery,” Dr. Ghigiarelli said.
Red light at wavelengths from 650 to 820 nm can enter muscle cells, where it is absorbed by mitochondria and boosts their energy production, he said. At the time of his research, some exercise science researchers and athletes thought using light therapy before an event might also increase athletic performance, but according to Dr. Ghigiarelli, that use has not panned out.
Handheld red light and near-infrared light devices for muscle recovery are widely available, but it’s important to do your homework before buying one.
“You want to choose a device with the right energy production — the right wavelength of light, the right power — to be safe and effective,” he said.
For details, he recommends consulting a 2019 paper in The Brazilian Journal of Physical Therapy called “Clinical and scientific recommendations for the use of photobiomodulation therapy in exercise performance enhancement and post-exercise recovery: Current evidence and future directions.”
The paper, from the Laboratory of Phototherapy and Innovative Technologies in Health at the Universidade Nove de Julho in Sao Paulo, Brazil, recommends that for small muscle groups like the biceps or triceps, use red-light lasers or LED devices with a wavelength of 640 nm for red light or 950 nm for infrared light, at a power of 50-200 mW per diode for single-probe device types, at a dose of 20-60 J, given 5-10 minutes after exercise.
A version of this article appeared on Medscape.com.
A surprising therapy is showing promise for chronic pain, vision loss, and muscle recovery, among other conditions.
It’s not a pill, an injection, or surgery.
It’s light.
Yes, light. The thing that appears when you open the curtains, flip a switch, or strike a match.
Light illuminates our world and helps us see. Early human trials suggest it may help us heal in new ways as well.
“Phototherapy is still in its infancy,” said Mohab Ibrahim, MD, PhD, a professor of anesthesiology at the University of Arizona, Tucson, who studies the effects of light on chronic pain. “There are so many questions, a lot of things we do not understand yet. But that’s where it gets interesting. What we can conclude is that different colors of light can influence different biological functions.”
This growing field goes by several names. Light therapy. Phototherapy. Photobiomodulation.
It leverages known effects of light on human health — such as skin exposure to ultraviolet light producing vitamin D or blue light’s power to regulate human body clocks — to take light as medicine in surprising new directions.
New Science, Old Idea
The science is young, but the concept of using light to restore health is thousands of years old.
Hippocrates prescribed sunbathing to patients at his medical center on the Greek island of Kos in 400 BC. Florence Nightingale promoted sunshine, along with fresh air, as prerequisites for recovery in hospitals during the Civil War. A Danish doctor, Niels Finsen, won the Nobel Prize in 1903 for developing ultraviolet lamps to treat a tuberculosis-related skin condition. And worried parents of the 1930s sat their babies in front of mercury arc lamps, bought at the drugstore, to discourage rickets.
Today, light therapy is widely used in medicine for newborn jaundice, psoriasis, and seasonal affective disorder and in light-activated treatments for cancers of the esophagus and lungs, as well as for actinic keratosis, a skin condition that can lead to cancer.
But researchers are finding that light may be capable of far more, particularly in conditions with few treatment options or where available drugs have unwanted side effects.
How Red Light Could Restore Vision
When 100 midlife and older adults, aged 53-91, with the dry form of age-related macular degeneration (AMD) were treated with an experimental red-light therapy or a sham therapy, the light treatment group showed signs of improved vision, as measured on a standard eye chart.
Volunteers received the therapy three times a week for 3-5 weeks, every 4 months for 2 years. By the study’s end, 67% of those treated with light could read an additional five letters on the chart, and 20% could read 10 or more. About 7% developed geographic atrophy — the most advanced, vision-threatening stage of dry AMD — compared with 24% in the sham group.
The study, called LIGHTSITE III, was conducted at 10 ophthalmology centers across the United States. The device they used — the Valeda Light Delivery System from medical device company LumiThera — is available in Europe and now being reviewed by the Food and Drug Administration (FDA).
Exposure to red light at the wavelengths used in the study likely revitalizes failing mitochondria — the power plants inside cells — so they produce more energy, the researchers say.
“This is the first therapy for dry AMD that’s actually shown a benefit in improving vision,” said study coauthor Richard Rosen, MD, chair of ophthalmology at the Icahn School of Medicine at Mount Sinai and chief of Retinal Services at the New York Eye and Ear Infirmary in New York City. “Supplements called AREDS can reduce progression, and in wet AMD we can improve vision loss with injections. But in dry AMD, none of the treatments studied in the past have improved it.”
AMD develops when the eyes can’t break down natural by-products, which glom together as clumps of protein called drusen. Drusen can lodge under the retina, eventually damaging tissue.
“Retinal epithelial cells, a single layer of cells that cares for the photoreceptors in the eyes, are there for life,” Dr. Rosen said. “They have a tremendous capacity to repair themselves, but things [such as aging and smoking] get in the way.”
“I’m proposing,” Dr. Rosen said, “that by boosting energy levels in cells [with red light], we’re improving normal repair mechanisms.”
Lab studies support this idea.
In a 2017 mouse study from the University College London Institute of Ophthalmology in England, retinal function improved by 25% in old mice exposed to red light. And a 2019 study from the Ophthalmological Research Foundation, Oviedo, Spain, found that exposure to blue light harmed the mitochondria in retina cells, while red light somewhat counteracted the losses.
If cleared by the FDA — which the company anticipated could happen in 2024 — LumiThera’s light delivery device will likely be most useful in the beginning stages of dry AMD, Dr. Rosen said. “I think treatment of early dry AMD will be huge.”
Eventually, light therapy may also be valuable in treating or managing glaucoma and diabetic retinopathy.
For now, Dr. Rosen recommended that clinicians and consumers with AMD skip over-the-counter (OTC) red-light therapy devices currently on the market.
“We don’t know what kind of light the devices produce,” he said. “The wavelengths can vary. The eyes are delicate. Experimenting on your own may be hazardous to your vision.”
Green Light for Pain Relief
On his way to the pharmacy to pick up pain relievers for a headache, Dr. Ibrahim passed Gene C. Reid Park in Tucson. Recalling how his brother eased headaches by sitting in his backyard, Dr. Ibrahim pulled over.
“Reid Park is probably one of the greenest areas of Tucson,” said Dr. Ibrahim, who also serves as medical director of the Comprehensive Center for Pain & Addiction at Banner-University Medical Center Phoenix in Arizona. “I spent a half hour or 40 minutes there, and my headache felt better.”
Being outdoors in a green space may be soothing for lots of reasons, like the quiet or the fresh air. But there’s also sunlight reflected off and shining through greenery. The experience inspired Dr. Ibrahim to take a closer look at the effects of green light on chronic pain.
In his 2021 study of 29 people with migraines, participants reported that, after daily exposure to green light for 10 weeks, the number of days per month when they had headaches fell from 7.9 to 2.4 for those who had episodic migraines and from 22.3 to 9.4 for those with chronic migraines. In another 2021 study, 21 people with fibromyalgia who had green light therapy for 10 weeks said their average, self-reported pain intensity fell from 8.4 to 4.9 on a 10-point scale used at the University of Arizona’s pain clinic.
Volunteers in both studies got their light therapy at home, switching on green LED lights while they listened to music, read a book, relaxed, or exercised for 1 or 2 hours daily. The lights were within their field of vision, but they did not look directly at them.
Dr. Ibrahim now has funding from the Department of Defense and Department of Veterans Affairs to find out why green light alters pain perception.
“What we know is that the visual system is connected to certain areas of the brain that also modulate pain,” he said. “We are trying to understand the connection.”
Padma Gulur, MD, a professor of anesthesiology and population health and director of Pain Management Strategy and Opioid Surveillance at Duke University, Durham, North Carolina, saw similar results in a 2023 study of 45 people with fibromyalgia. But instead of using a light source, volunteers wore glasses with clear, green, or blue lenses for 4 hours a day.
After 2 weeks, 33% in the green lens group reduced their use of opioids by 10% or more, compared with 11% in the blue lens group and 8% who wore clear lenses. Previous studies have found green light affects levels of the feel-good brain chemical serotonin and stimulates the body’s own opioid system, the authors noted.
“Green light helps your body control and reduce pain,” Dr. Gulur said. It “seems to help with pain relief by affecting the body’s natural pain management system. This effect appears to play a crucial role in antinociception — reducing the sensation of pain; antiallodynia — preventing normal, nonpainful stimuli from causing pain; and antihyperalgesia — reducing heightened sensitivity to pain.”
Light therapy could help pain patients reduce their dose of opioids or even forgo the drugs altogether, Dr. Gulur said. “It is our hope this will become a useful adjuvant therapy to manage pain.”
In the University of Arizona studies, some patients on green-light therapy stopped their medications completely. Even if they didn’t, other benefits appeared. “They had improved quality of life, decreased depression and anxiety, and improved sleep,” Dr. Ibrahim said.
But not just any green light or green-tinted glasses will work, both researchers said. “We have found there are specific frequencies of green light that give this benefit,” Dr. Gulur said. “OTC products may not be helpful for that reason.”
While Dr. Ibrahim said it could be possible for healthcare practitioners and consumers to consult his studies and put together an inexpensive green-light device at home while carefully following the protocol participants used in the studies , it would first be a good idea for patients to talk with their family doctor or a pain specialist.
“A headache is not always just a headache,” Dr. Ibrahim said. “It could be some other abnormality that needs diagnosis and treatment. If you have long-lasting pain or pain that’s getting worse, it’s always better to discuss it with your physician.”
Helping Muscles Recover With Red Light
Intense exercise — whether it’s a sprint at the end of a morning run, an extra set of biceps curls, or a weekend of all-day DIY home improvement projects — can temporarily damage muscle, causing soreness, inflammation, and even swelling. Phototherapy with red and near-infrared light is widely used by sports trainers, physical therapists, and athletes to aid in recovery. It may even work better than a trendy plunge in an ice bath, according to a 2019 Texas State University review.
But how does it work? Jamie Ghigiarelli, PhD, professor of Allied Health & Kinesiology at Hofstra University in Hempstead, New York, looked closely at signs of inflammation and muscle damage in 12 athletes to find out.
Study participants overtaxed their muscles with rounds of chin-ups, high-speed sprints, and repeated bench presses. Afterward, they relaxed in a full-body red-light therapy bed or in a similar bed without lights.
The results, published in 2020, showed that blood levels of creatine kinase — an enzyme that’s elevated by muscle damage — were 18% lower 1-3 days after exercising for the light-bed group than for the control group.
“Photobiomodulation seems to help with muscle recovery,” Dr. Ghigiarelli said.
Red light at wavelengths from 650 to 820 nm can enter muscle cells, where it is absorbed by mitochondria and boosts their energy production, he said. At the time of his research, some exercise science researchers and athletes thought using light therapy before an event might also increase athletic performance, but according to Dr. Ghigiarelli, that use has not panned out.
Handheld red light and near-infrared light devices for muscle recovery are widely available, but it’s important to do your homework before buying one.
“You want to choose a device with the right energy production — the right wavelength of light, the right power — to be safe and effective,” he said.
For details, he recommends consulting a 2019 paper in The Brazilian Journal of Physical Therapy called “Clinical and scientific recommendations for the use of photobiomodulation therapy in exercise performance enhancement and post-exercise recovery: Current evidence and future directions.”
The paper, from the Laboratory of Phototherapy and Innovative Technologies in Health at the Universidade Nove de Julho in Sao Paulo, Brazil, recommends that for small muscle groups like the biceps or triceps, use red-light lasers or LED devices with a wavelength of 640 nm for red light or 950 nm for infrared light, at a power of 50-200 mW per diode for single-probe device types, at a dose of 20-60 J, given 5-10 minutes after exercise.
A version of this article appeared on Medscape.com.
Chronotherapy: Why Timing Drugs to Our Body Clocks May Work
Do drugs work better if taken by the clock?
A new analysis published in The Lancet journal’s eClinicalMedicine suggests: Yes, they do — if you consider the patient’s individual body clock. The study is the first to find that timing blood pressure drugs to a person’s personal “chronotype” — that is, whether they are a night owl or an early bird — may reduce the risk for a heart attack.
The findings represent a significant advance in the field of circadian medicine or “chronotherapy” — timing drug administration to circadian rhythms. A growing stack of research suggests this approach could reduce side effects and improve the effectiveness of a wide range of therapies, including vaccines, cancer treatments, and drugs for depression, glaucoma, pain, seizures, and other conditions. Still, despite decades of research, time of day is rarely considered in writing prescriptions.
“We are really just at the beginning of an exciting new way of looking at patient care,” said Kenneth A. Dyar, PhD, whose lab at Helmholtz Zentrum München’s Institute for Diabetes and Cancer focuses on metabolic physiology. Dr. Dyar is co-lead author of the new blood pressure analysis.
“Chronotherapy is a rapidly growing field,” he said, “and I suspect we are soon going to see more and more studies focused on ‘personalized chronotherapy,’ not only in hypertension but also potentially in other clinical areas.”
The ‘Missing Piece’ in Chronotherapy Research
Blood pressure drugs have long been chronotherapy’s battleground. After all, blood pressure follows a circadian rhythm, peaking in the morning and dropping at night.
That healthy overnight dip can disappear in people with diabetes, kidney disease, and obstructive sleep apnea. Some physicians have suggested a bed-time dose to restore that dip. But studies have had mixed results, so “take at bedtime” has become a less common recommendation in recent years.
But the debate continued. After a large 2019 Spanish study found that bedtime doses had benefits so big that the results drew questions, an even larger, 2022 randomized, controlled trial from the University of Dundee in Dundee, Scotland — called the TIME study — aimed to settle the question.
Researchers assigned over 21,000 people to take morning or night hypertension drugs for several years and found no difference in cardiovascular outcomes.
“We did this study thinking nocturnal blood pressure tablets might be better,” said Thomas MacDonald, MD, professor emeritus of clinical pharmacology and pharmacoepidemiology at the University of Dundee and principal investigator for the TIME study and the recent chronotype analysis. “But there was no difference for heart attacks, strokes, or vascular death.”
So, the researchers then looked at participants’ chronotypes, sorting outcomes based on whether the participants were late-to-bed, late-to-rise “night owls” or early-to-bed, early-to-rise “morning larks.”
Their analysis of these 5358 TIME participants found the following results: Risk for hospitalization for a heart attack was at least 34% lower for “owls” who took their drugs at bedtime. By contrast, owls’ heart attack risk was at least 62% higher with morning doses. For “larks,” the opposite was true. Morning doses were associated with an 11% lower heart attack risk and night doses with an 11% higher risk, according to supplemental data.
The personalized approach could explain why some previous chronotherapy studies have failed to show a benefit. Those studies did not individualize drug timing as this one did. But personalization could be key to circadian medicine’s success.
“Our ‘internal personal time’ appears to be an important variable to consider when dosing antihypertensives,” said co-lead author Filippo Pigazzani, MD, PhD, clinical senior lecturer and honorary consultant cardiologist at the University of Dundee School of Medicine. “Chronotherapy research has been going on for decades. We knew there was something important with time of day. But researchers haven’t considered the internal time of individual people. I think that is the missing piece.”
The analysis has several important limitations, the researchers said. A total of 95% of participants were White. And it was an observational study, not a true randomized comparison. “We started it late in the original TIME study,” Dr. MacDonald said. “You could argue we were reporting on those who survived long enough to get into the analysis.” More research is needed, they concluded.
Looking Beyond Blood Pressure
What about the rest of the body? “Almost all the cells of our body contain ‘circadian clocks’ that are synchronized by daily environmental cues, including light-dark, activity-rest, and feeding-fasting cycles,” said Dr. Dyar.
An estimated 50% of prescription drugs hit targets in the body that have circadian patterns. So, experts suspect that syncing a drug with a person’s body clock might increase effectiveness of many drugs.
A handful of US Food and Drug Administration–approved drugs already have time-of-day recommendations on the label for effectiveness or to limit side effects, including bedtime or evening for the insomnia drug Ambien, the HIV antiviral Atripla, and cholesterol-lowering Zocor. Others are intended to be taken with or after your last meal of the day, such as the long-acting insulin Levemir and the cardiovascular drug Xarelto. A morning recommendation comes with the proton pump inhibitor Nexium and the attention-deficit/hyperactivity disorder drug Ritalin.
Interest is expanding. About one third of the papers published about chronotherapy in the past 25 years have come out in the past 5 years. The May 2024 meeting of the Society for Research on Biological Rhythms featured a day-long session aimed at bringing clinicians up to speed. An organization called the International Association of Circadian Health Clinics is trying to bring circadian medicine findings to clinicians and their patients and to support research.
Moreover, while recent research suggests minding the clock could have benefits for a wide range of treatments, ignoring it could cause problems.
In a Massachusetts Institute of Technology study published in April in Science Advances, researchers looked at engineered livers made from human donor cells and found more than 300 genes that operate on a circadian schedule, many with roles in drug metabolism. They also found that circadian patterns affected the toxicity of acetaminophen and atorvastatin. Identifying the time of day to take these drugs could maximize effectiveness and minimize adverse effects, the researchers said.
Timing and the Immune System
Circadian rhythms are also seen in immune processes. In a 2023 study in The Journal of Clinical Investigation of vaccine data from 1.5 million people in Israel, researchers found that children and older adults who got their second dose of the Pfizer mRNA COVID vaccine earlier in the day were about 36% less likely to be hospitalized with SARS-CoV-2 infection than those who got an evening shot.
“The sweet spot in our data was somewhere around late morning to late afternoon,” said lead researcher Jeffrey Haspel, MD, PhD, associate professor of medicine in the division of pulmonary and critical care medicine at Washington University School of Medicine in St. Louis.
In a multicenter, 2024 analysis of 13 studies of immunotherapy for advanced cancers in 1663 people, researchers found treatment earlier in the day was associated with longer survival time and longer survival without cancer progression.
“Patients with selected metastatic cancers seemed to largely benefit from early [time of day] infusions, which is consistent with circadian mechanisms in immune-cell functions and trafficking,” the researchers noted. But “retrospective randomized trials are needed to establish recommendations for optimal circadian timing.”
Other research suggests or is investigating possible chronotherapy benefits for depression, glaucoma, respiratory diseases, stroke treatment, epilepsy, and sedatives used in surgery. So why aren’t healthcare providers adding time of day to more prescriptions? “What’s missing is more reliable data,” Dr. Dyar said.
Should You Use Chronotherapy Now?
Experts emphasize that more research is needed before doctors use chronotherapy and before medical organizations include it in treatment recommendations. But for some patients, circadian dosing may be worth a try:
Night owls whose blood pressure isn’t well controlled. Dr. Dyar and Dr. Pigazzani said night-time blood pressure drugs may be helpful for people with a “late chronotype.” Of course, patients shouldn’t change their medication schedule on their own, they said. And doctors may want to consider other concerns, like more overnight bathroom visits with evening diuretics.
In their study, the researchers determined participants’ chronotype with a few questions from the Munich Chronotype Questionnaire about what time they fell asleep and woke up on workdays and days off and whether they considered themselves “morning types” or “evening types.” (The questions can be found in supplementary data for the study.)
If a physician thinks matching the timing of a dose with chronotype would help, they can consider it, Dr. Pigazzani said. “However, I must add that this was an observational study, so I would advise healthcare practitioners to wait for our data to be confirmed in new RCTs of personalized chronotherapy of hypertension.”
Children and older adults getting vaccines. Timing COVID shots and possibly other vaccines from late morning to mid-afternoon could have a small benefit for individuals and a bigger public-health benefit, Dr. Haspel said. But the most important thing is getting vaccinated. “If you can only get one in the evening, it’s still worthwhile. Timing may add oomph at a public-health level for more vulnerable groups.”
A version of this article appeared on Medscape.com.
Do drugs work better if taken by the clock?
A new analysis published in The Lancet journal’s eClinicalMedicine suggests: Yes, they do — if you consider the patient’s individual body clock. The study is the first to find that timing blood pressure drugs to a person’s personal “chronotype” — that is, whether they are a night owl or an early bird — may reduce the risk for a heart attack.
The findings represent a significant advance in the field of circadian medicine or “chronotherapy” — timing drug administration to circadian rhythms. A growing stack of research suggests this approach could reduce side effects and improve the effectiveness of a wide range of therapies, including vaccines, cancer treatments, and drugs for depression, glaucoma, pain, seizures, and other conditions. Still, despite decades of research, time of day is rarely considered in writing prescriptions.
“We are really just at the beginning of an exciting new way of looking at patient care,” said Kenneth A. Dyar, PhD, whose lab at Helmholtz Zentrum München’s Institute for Diabetes and Cancer focuses on metabolic physiology. Dr. Dyar is co-lead author of the new blood pressure analysis.
“Chronotherapy is a rapidly growing field,” he said, “and I suspect we are soon going to see more and more studies focused on ‘personalized chronotherapy,’ not only in hypertension but also potentially in other clinical areas.”
The ‘Missing Piece’ in Chronotherapy Research
Blood pressure drugs have long been chronotherapy’s battleground. After all, blood pressure follows a circadian rhythm, peaking in the morning and dropping at night.
That healthy overnight dip can disappear in people with diabetes, kidney disease, and obstructive sleep apnea. Some physicians have suggested a bed-time dose to restore that dip. But studies have had mixed results, so “take at bedtime” has become a less common recommendation in recent years.
But the debate continued. After a large 2019 Spanish study found that bedtime doses had benefits so big that the results drew questions, an even larger, 2022 randomized, controlled trial from the University of Dundee in Dundee, Scotland — called the TIME study — aimed to settle the question.
Researchers assigned over 21,000 people to take morning or night hypertension drugs for several years and found no difference in cardiovascular outcomes.
“We did this study thinking nocturnal blood pressure tablets might be better,” said Thomas MacDonald, MD, professor emeritus of clinical pharmacology and pharmacoepidemiology at the University of Dundee and principal investigator for the TIME study and the recent chronotype analysis. “But there was no difference for heart attacks, strokes, or vascular death.”
So, the researchers then looked at participants’ chronotypes, sorting outcomes based on whether the participants were late-to-bed, late-to-rise “night owls” or early-to-bed, early-to-rise “morning larks.”
Their analysis of these 5358 TIME participants found the following results: Risk for hospitalization for a heart attack was at least 34% lower for “owls” who took their drugs at bedtime. By contrast, owls’ heart attack risk was at least 62% higher with morning doses. For “larks,” the opposite was true. Morning doses were associated with an 11% lower heart attack risk and night doses with an 11% higher risk, according to supplemental data.
The personalized approach could explain why some previous chronotherapy studies have failed to show a benefit. Those studies did not individualize drug timing as this one did. But personalization could be key to circadian medicine’s success.
“Our ‘internal personal time’ appears to be an important variable to consider when dosing antihypertensives,” said co-lead author Filippo Pigazzani, MD, PhD, clinical senior lecturer and honorary consultant cardiologist at the University of Dundee School of Medicine. “Chronotherapy research has been going on for decades. We knew there was something important with time of day. But researchers haven’t considered the internal time of individual people. I think that is the missing piece.”
The analysis has several important limitations, the researchers said. A total of 95% of participants were White. And it was an observational study, not a true randomized comparison. “We started it late in the original TIME study,” Dr. MacDonald said. “You could argue we were reporting on those who survived long enough to get into the analysis.” More research is needed, they concluded.
Looking Beyond Blood Pressure
What about the rest of the body? “Almost all the cells of our body contain ‘circadian clocks’ that are synchronized by daily environmental cues, including light-dark, activity-rest, and feeding-fasting cycles,” said Dr. Dyar.
An estimated 50% of prescription drugs hit targets in the body that have circadian patterns. So, experts suspect that syncing a drug with a person’s body clock might increase effectiveness of many drugs.
A handful of US Food and Drug Administration–approved drugs already have time-of-day recommendations on the label for effectiveness or to limit side effects, including bedtime or evening for the insomnia drug Ambien, the HIV antiviral Atripla, and cholesterol-lowering Zocor. Others are intended to be taken with or after your last meal of the day, such as the long-acting insulin Levemir and the cardiovascular drug Xarelto. A morning recommendation comes with the proton pump inhibitor Nexium and the attention-deficit/hyperactivity disorder drug Ritalin.
Interest is expanding. About one third of the papers published about chronotherapy in the past 25 years have come out in the past 5 years. The May 2024 meeting of the Society for Research on Biological Rhythms featured a day-long session aimed at bringing clinicians up to speed. An organization called the International Association of Circadian Health Clinics is trying to bring circadian medicine findings to clinicians and their patients and to support research.
Moreover, while recent research suggests minding the clock could have benefits for a wide range of treatments, ignoring it could cause problems.
In a Massachusetts Institute of Technology study published in April in Science Advances, researchers looked at engineered livers made from human donor cells and found more than 300 genes that operate on a circadian schedule, many with roles in drug metabolism. They also found that circadian patterns affected the toxicity of acetaminophen and atorvastatin. Identifying the time of day to take these drugs could maximize effectiveness and minimize adverse effects, the researchers said.
Timing and the Immune System
Circadian rhythms are also seen in immune processes. In a 2023 study in The Journal of Clinical Investigation of vaccine data from 1.5 million people in Israel, researchers found that children and older adults who got their second dose of the Pfizer mRNA COVID vaccine earlier in the day were about 36% less likely to be hospitalized with SARS-CoV-2 infection than those who got an evening shot.
“The sweet spot in our data was somewhere around late morning to late afternoon,” said lead researcher Jeffrey Haspel, MD, PhD, associate professor of medicine in the division of pulmonary and critical care medicine at Washington University School of Medicine in St. Louis.
In a multicenter, 2024 analysis of 13 studies of immunotherapy for advanced cancers in 1663 people, researchers found treatment earlier in the day was associated with longer survival time and longer survival without cancer progression.
“Patients with selected metastatic cancers seemed to largely benefit from early [time of day] infusions, which is consistent with circadian mechanisms in immune-cell functions and trafficking,” the researchers noted. But “retrospective randomized trials are needed to establish recommendations for optimal circadian timing.”
Other research suggests or is investigating possible chronotherapy benefits for depression, glaucoma, respiratory diseases, stroke treatment, epilepsy, and sedatives used in surgery. So why aren’t healthcare providers adding time of day to more prescriptions? “What’s missing is more reliable data,” Dr. Dyar said.
Should You Use Chronotherapy Now?
Experts emphasize that more research is needed before doctors use chronotherapy and before medical organizations include it in treatment recommendations. But for some patients, circadian dosing may be worth a try:
Night owls whose blood pressure isn’t well controlled. Dr. Dyar and Dr. Pigazzani said night-time blood pressure drugs may be helpful for people with a “late chronotype.” Of course, patients shouldn’t change their medication schedule on their own, they said. And doctors may want to consider other concerns, like more overnight bathroom visits with evening diuretics.
In their study, the researchers determined participants’ chronotype with a few questions from the Munich Chronotype Questionnaire about what time they fell asleep and woke up on workdays and days off and whether they considered themselves “morning types” or “evening types.” (The questions can be found in supplementary data for the study.)
If a physician thinks matching the timing of a dose with chronotype would help, they can consider it, Dr. Pigazzani said. “However, I must add that this was an observational study, so I would advise healthcare practitioners to wait for our data to be confirmed in new RCTs of personalized chronotherapy of hypertension.”
Children and older adults getting vaccines. Timing COVID shots and possibly other vaccines from late morning to mid-afternoon could have a small benefit for individuals and a bigger public-health benefit, Dr. Haspel said. But the most important thing is getting vaccinated. “If you can only get one in the evening, it’s still worthwhile. Timing may add oomph at a public-health level for more vulnerable groups.”
A version of this article appeared on Medscape.com.
Do drugs work better if taken by the clock?
A new analysis published in The Lancet journal’s eClinicalMedicine suggests: Yes, they do — if you consider the patient’s individual body clock. The study is the first to find that timing blood pressure drugs to a person’s personal “chronotype” — that is, whether they are a night owl or an early bird — may reduce the risk for a heart attack.
The findings represent a significant advance in the field of circadian medicine or “chronotherapy” — timing drug administration to circadian rhythms. A growing stack of research suggests this approach could reduce side effects and improve the effectiveness of a wide range of therapies, including vaccines, cancer treatments, and drugs for depression, glaucoma, pain, seizures, and other conditions. Still, despite decades of research, time of day is rarely considered in writing prescriptions.
“We are really just at the beginning of an exciting new way of looking at patient care,” said Kenneth A. Dyar, PhD, whose lab at Helmholtz Zentrum München’s Institute for Diabetes and Cancer focuses on metabolic physiology. Dr. Dyar is co-lead author of the new blood pressure analysis.
“Chronotherapy is a rapidly growing field,” he said, “and I suspect we are soon going to see more and more studies focused on ‘personalized chronotherapy,’ not only in hypertension but also potentially in other clinical areas.”
The ‘Missing Piece’ in Chronotherapy Research
Blood pressure drugs have long been chronotherapy’s battleground. After all, blood pressure follows a circadian rhythm, peaking in the morning and dropping at night.
That healthy overnight dip can disappear in people with diabetes, kidney disease, and obstructive sleep apnea. Some physicians have suggested a bed-time dose to restore that dip. But studies have had mixed results, so “take at bedtime” has become a less common recommendation in recent years.
But the debate continued. After a large 2019 Spanish study found that bedtime doses had benefits so big that the results drew questions, an even larger, 2022 randomized, controlled trial from the University of Dundee in Dundee, Scotland — called the TIME study — aimed to settle the question.
Researchers assigned over 21,000 people to take morning or night hypertension drugs for several years and found no difference in cardiovascular outcomes.
“We did this study thinking nocturnal blood pressure tablets might be better,” said Thomas MacDonald, MD, professor emeritus of clinical pharmacology and pharmacoepidemiology at the University of Dundee and principal investigator for the TIME study and the recent chronotype analysis. “But there was no difference for heart attacks, strokes, or vascular death.”
So, the researchers then looked at participants’ chronotypes, sorting outcomes based on whether the participants were late-to-bed, late-to-rise “night owls” or early-to-bed, early-to-rise “morning larks.”
Their analysis of these 5358 TIME participants found the following results: Risk for hospitalization for a heart attack was at least 34% lower for “owls” who took their drugs at bedtime. By contrast, owls’ heart attack risk was at least 62% higher with morning doses. For “larks,” the opposite was true. Morning doses were associated with an 11% lower heart attack risk and night doses with an 11% higher risk, according to supplemental data.
The personalized approach could explain why some previous chronotherapy studies have failed to show a benefit. Those studies did not individualize drug timing as this one did. But personalization could be key to circadian medicine’s success.
“Our ‘internal personal time’ appears to be an important variable to consider when dosing antihypertensives,” said co-lead author Filippo Pigazzani, MD, PhD, clinical senior lecturer and honorary consultant cardiologist at the University of Dundee School of Medicine. “Chronotherapy research has been going on for decades. We knew there was something important with time of day. But researchers haven’t considered the internal time of individual people. I think that is the missing piece.”
The analysis has several important limitations, the researchers said. A total of 95% of participants were White. And it was an observational study, not a true randomized comparison. “We started it late in the original TIME study,” Dr. MacDonald said. “You could argue we were reporting on those who survived long enough to get into the analysis.” More research is needed, they concluded.
Looking Beyond Blood Pressure
What about the rest of the body? “Almost all the cells of our body contain ‘circadian clocks’ that are synchronized by daily environmental cues, including light-dark, activity-rest, and feeding-fasting cycles,” said Dr. Dyar.
An estimated 50% of prescription drugs hit targets in the body that have circadian patterns. So, experts suspect that syncing a drug with a person’s body clock might increase effectiveness of many drugs.
A handful of US Food and Drug Administration–approved drugs already have time-of-day recommendations on the label for effectiveness or to limit side effects, including bedtime or evening for the insomnia drug Ambien, the HIV antiviral Atripla, and cholesterol-lowering Zocor. Others are intended to be taken with or after your last meal of the day, such as the long-acting insulin Levemir and the cardiovascular drug Xarelto. A morning recommendation comes with the proton pump inhibitor Nexium and the attention-deficit/hyperactivity disorder drug Ritalin.
Interest is expanding. About one third of the papers published about chronotherapy in the past 25 years have come out in the past 5 years. The May 2024 meeting of the Society for Research on Biological Rhythms featured a day-long session aimed at bringing clinicians up to speed. An organization called the International Association of Circadian Health Clinics is trying to bring circadian medicine findings to clinicians and their patients and to support research.
Moreover, while recent research suggests minding the clock could have benefits for a wide range of treatments, ignoring it could cause problems.
In a Massachusetts Institute of Technology study published in April in Science Advances, researchers looked at engineered livers made from human donor cells and found more than 300 genes that operate on a circadian schedule, many with roles in drug metabolism. They also found that circadian patterns affected the toxicity of acetaminophen and atorvastatin. Identifying the time of day to take these drugs could maximize effectiveness and minimize adverse effects, the researchers said.
Timing and the Immune System
Circadian rhythms are also seen in immune processes. In a 2023 study in The Journal of Clinical Investigation of vaccine data from 1.5 million people in Israel, researchers found that children and older adults who got their second dose of the Pfizer mRNA COVID vaccine earlier in the day were about 36% less likely to be hospitalized with SARS-CoV-2 infection than those who got an evening shot.
“The sweet spot in our data was somewhere around late morning to late afternoon,” said lead researcher Jeffrey Haspel, MD, PhD, associate professor of medicine in the division of pulmonary and critical care medicine at Washington University School of Medicine in St. Louis.
In a multicenter, 2024 analysis of 13 studies of immunotherapy for advanced cancers in 1663 people, researchers found treatment earlier in the day was associated with longer survival time and longer survival without cancer progression.
“Patients with selected metastatic cancers seemed to largely benefit from early [time of day] infusions, which is consistent with circadian mechanisms in immune-cell functions and trafficking,” the researchers noted. But “retrospective randomized trials are needed to establish recommendations for optimal circadian timing.”
Other research suggests or is investigating possible chronotherapy benefits for depression, glaucoma, respiratory diseases, stroke treatment, epilepsy, and sedatives used in surgery. So why aren’t healthcare providers adding time of day to more prescriptions? “What’s missing is more reliable data,” Dr. Dyar said.
Should You Use Chronotherapy Now?
Experts emphasize that more research is needed before doctors use chronotherapy and before medical organizations include it in treatment recommendations. But for some patients, circadian dosing may be worth a try:
Night owls whose blood pressure isn’t well controlled. Dr. Dyar and Dr. Pigazzani said night-time blood pressure drugs may be helpful for people with a “late chronotype.” Of course, patients shouldn’t change their medication schedule on their own, they said. And doctors may want to consider other concerns, like more overnight bathroom visits with evening diuretics.
In their study, the researchers determined participants’ chronotype with a few questions from the Munich Chronotype Questionnaire about what time they fell asleep and woke up on workdays and days off and whether they considered themselves “morning types” or “evening types.” (The questions can be found in supplementary data for the study.)
If a physician thinks matching the timing of a dose with chronotype would help, they can consider it, Dr. Pigazzani said. “However, I must add that this was an observational study, so I would advise healthcare practitioners to wait for our data to be confirmed in new RCTs of personalized chronotherapy of hypertension.”
Children and older adults getting vaccines. Timing COVID shots and possibly other vaccines from late morning to mid-afternoon could have a small benefit for individuals and a bigger public-health benefit, Dr. Haspel said. But the most important thing is getting vaccinated. “If you can only get one in the evening, it’s still worthwhile. Timing may add oomph at a public-health level for more vulnerable groups.”
A version of this article appeared on Medscape.com.
New Era? ‘Double Selective’ Antibiotic Spares the Microbiome
A new antibiotic uses a never-before-seen mechanism to deliver a direct hit on tough-to-treat infections while leaving beneficial microbes alone. The strategy could lead to a new class of antibiotics that attack dangerous bacteria in a powerful new way, overcoming current drug resistance while sparing the gut microbiome.
“The biggest takeaway is the double-selective component,” said co-lead author Kristen A. Muñoz, PhD, who performed the research as a doctoral student at University of Illinois at Urbana-Champaign (UIUC). “We were able to develop a drug that not only targets problematic pathogens, but because it is selective for these pathogens only, we can spare the good bacteria and preserve the integrity of the microbiome.”
The drug goes after Gram-negative bacteria — pathogens responsible for debilitating and even fatal infections like gastroenteritis, urinary tract infections, pneumonia, sepsis, and cholera. The arsenal of antibiotics against them is old, with no new classes specifically targeting these bacteria coming on the market since 1968.
Many of these bugs have become resistant to one or more antibiotics, with deadly consequences. And antibiotics against them can also wipe out beneficial gut bacteria, allowing serious secondary infections to flare up.
In a study published in Nature, the drug lolamicin knocked out or reduced 130 strains of antibiotic-resistant Gram-negative bacteria in cell cultures. It also successfully treated drug-resistant bloodstream infections and pneumonia in mice while sparing their gut microbiome.
With their microbiomes intact, the mice then fought off secondary infection with Clostridioides difficile (a leading cause of opportunistic and sometimes fatal infections in US health care facilities), while mice treated with other compounds that damaged their microbiome succumbed.
How It Works
Like a well-built medieval castle, Gram-negative bacteria are encased in two protective walls, or membranes. Dr. Muñoz and her team at UIUC set out to breach this defense by finding compounds that hinder the “Lol system,” which ferries lipoproteins between them.
From one compound they constructed lolamicin, which can stop Gram-negative pathogens — with little effect on Gram-negative beneficial bacteria and no effect on Gram-positive bacteria.
“Gram-positive bacteria do not have an outer membrane, so they do not possess the Lol system,” Dr. Muñoz said. “When we compared the sequences of the Lol system in certain Gram-negative pathogens to Gram-negative commensal [beneficial] gut bacteria, we saw that the Lol systems were pretty different.”
Tossing a monkey wrench into the Lol system may be the study’s biggest contribution to future antibiotic development, said Kim Lewis, PhD, professor of Biology and director of Antimicrobial Discovery Center at Northeastern University, Boston, who has discovered several antibiotics now in preclinical research. One, darobactin, targets Gram-negative bugs without affecting the gut microbiome. Another, teixobactin, takes down Gram-positive bacteria without causing drug resistance.
“Lolamicin hits a novel target. I would say that’s the most significant study finding,” said Dr. Lewis, who was not involved in the study. “That is rare. If you look at antibiotics introduced since 1968, they have been modifications of existing antibiotics or, rarely, new chemically but hitting the same proven targets. This one hits something properly new, and [that’s] what I found perhaps the most original and interesting.”
Kirk E. Hevener, PharmD, PhD, associate professor of Pharmaceutical Sciences at the University of Tennessee Health Science Center, Memphis, Tennessee, agreed. (Dr. Hevener also was not involved in the study.) “Lolamicin works by targeting a unique Gram-negative transport system. No currently approved antibacterials work in this way, meaning it potentially represents the first of a new class of antibacterials with narrow-spectrum Gram-negative activity and low gastrointestinal disturbance,” said Dr. Hevener, whose research looks at new antimicrobial drug targets.
The UIUC researchers noted that lolamicin has one drawback: Bacteria frequently developed resistance to it. But in future work, it could be tweaked, combined with other antibiotics, or used as a template for finding other Lol system attackers, they said.
“There is still a good amount of work cut out for us in terms of assessing the clinical translatability of lolamicin, but we are hopeful for the future of this drug,” Dr. Muñoz said.
Addressing a Dire Need
Bringing such a drug to market — from discovery to Food and Drug Administration approval — could take more than a decade, said Dr. Hevener. And new agents, especially for Gram-negative bugs, are sorely needed.
Not only do these bacteria shield themselves with a double membrane but they also “have more complex resistance mechanisms including special pumps that can remove antibacterial drugs from the cell before they can be effective,” Dr. Hevener said.
As a result, drug-resistant Gram-negative bacteria are making treatment of severe infections such as sepsis and pneumonia in health care settings difficult.
Bloodstream infections with drug-resistant Klebsiella pneumoniae have a 40% mortality rate, Dr. Lewis said. And microbiome damage caused by antibiotics is also widespread and deadly, wiping out communities of helpful, protective gut bacteria. That contributes to over half of the C. difficile infections that affect 500,000 people and kill 30,000 a year in the United States.
“Our arsenal of antibacterials that can be used to treat Gram-negative infections is dangerously low,” Dr. Hevener said. “Research will always be needed to develop new antibacterials with novel mechanisms of activity that can bypass bacterial resistance mechanisms.”
A version of this article appeared on Medscape.com.
A new antibiotic uses a never-before-seen mechanism to deliver a direct hit on tough-to-treat infections while leaving beneficial microbes alone. The strategy could lead to a new class of antibiotics that attack dangerous bacteria in a powerful new way, overcoming current drug resistance while sparing the gut microbiome.
“The biggest takeaway is the double-selective component,” said co-lead author Kristen A. Muñoz, PhD, who performed the research as a doctoral student at University of Illinois at Urbana-Champaign (UIUC). “We were able to develop a drug that not only targets problematic pathogens, but because it is selective for these pathogens only, we can spare the good bacteria and preserve the integrity of the microbiome.”
The drug goes after Gram-negative bacteria — pathogens responsible for debilitating and even fatal infections like gastroenteritis, urinary tract infections, pneumonia, sepsis, and cholera. The arsenal of antibiotics against them is old, with no new classes specifically targeting these bacteria coming on the market since 1968.
Many of these bugs have become resistant to one or more antibiotics, with deadly consequences. And antibiotics against them can also wipe out beneficial gut bacteria, allowing serious secondary infections to flare up.
In a study published in Nature, the drug lolamicin knocked out or reduced 130 strains of antibiotic-resistant Gram-negative bacteria in cell cultures. It also successfully treated drug-resistant bloodstream infections and pneumonia in mice while sparing their gut microbiome.
With their microbiomes intact, the mice then fought off secondary infection with Clostridioides difficile (a leading cause of opportunistic and sometimes fatal infections in US health care facilities), while mice treated with other compounds that damaged their microbiome succumbed.
How It Works
Like a well-built medieval castle, Gram-negative bacteria are encased in two protective walls, or membranes. Dr. Muñoz and her team at UIUC set out to breach this defense by finding compounds that hinder the “Lol system,” which ferries lipoproteins between them.
From one compound they constructed lolamicin, which can stop Gram-negative pathogens — with little effect on Gram-negative beneficial bacteria and no effect on Gram-positive bacteria.
“Gram-positive bacteria do not have an outer membrane, so they do not possess the Lol system,” Dr. Muñoz said. “When we compared the sequences of the Lol system in certain Gram-negative pathogens to Gram-negative commensal [beneficial] gut bacteria, we saw that the Lol systems were pretty different.”
Tossing a monkey wrench into the Lol system may be the study’s biggest contribution to future antibiotic development, said Kim Lewis, PhD, professor of Biology and director of Antimicrobial Discovery Center at Northeastern University, Boston, who has discovered several antibiotics now in preclinical research. One, darobactin, targets Gram-negative bugs without affecting the gut microbiome. Another, teixobactin, takes down Gram-positive bacteria without causing drug resistance.
“Lolamicin hits a novel target. I would say that’s the most significant study finding,” said Dr. Lewis, who was not involved in the study. “That is rare. If you look at antibiotics introduced since 1968, they have been modifications of existing antibiotics or, rarely, new chemically but hitting the same proven targets. This one hits something properly new, and [that’s] what I found perhaps the most original and interesting.”
Kirk E. Hevener, PharmD, PhD, associate professor of Pharmaceutical Sciences at the University of Tennessee Health Science Center, Memphis, Tennessee, agreed. (Dr. Hevener also was not involved in the study.) “Lolamicin works by targeting a unique Gram-negative transport system. No currently approved antibacterials work in this way, meaning it potentially represents the first of a new class of antibacterials with narrow-spectrum Gram-negative activity and low gastrointestinal disturbance,” said Dr. Hevener, whose research looks at new antimicrobial drug targets.
The UIUC researchers noted that lolamicin has one drawback: Bacteria frequently developed resistance to it. But in future work, it could be tweaked, combined with other antibiotics, or used as a template for finding other Lol system attackers, they said.
“There is still a good amount of work cut out for us in terms of assessing the clinical translatability of lolamicin, but we are hopeful for the future of this drug,” Dr. Muñoz said.
Addressing a Dire Need
Bringing such a drug to market — from discovery to Food and Drug Administration approval — could take more than a decade, said Dr. Hevener. And new agents, especially for Gram-negative bugs, are sorely needed.
Not only do these bacteria shield themselves with a double membrane but they also “have more complex resistance mechanisms including special pumps that can remove antibacterial drugs from the cell before they can be effective,” Dr. Hevener said.
As a result, drug-resistant Gram-negative bacteria are making treatment of severe infections such as sepsis and pneumonia in health care settings difficult.
Bloodstream infections with drug-resistant Klebsiella pneumoniae have a 40% mortality rate, Dr. Lewis said. And microbiome damage caused by antibiotics is also widespread and deadly, wiping out communities of helpful, protective gut bacteria. That contributes to over half of the C. difficile infections that affect 500,000 people and kill 30,000 a year in the United States.
“Our arsenal of antibacterials that can be used to treat Gram-negative infections is dangerously low,” Dr. Hevener said. “Research will always be needed to develop new antibacterials with novel mechanisms of activity that can bypass bacterial resistance mechanisms.”
A version of this article appeared on Medscape.com.
A new antibiotic uses a never-before-seen mechanism to deliver a direct hit on tough-to-treat infections while leaving beneficial microbes alone. The strategy could lead to a new class of antibiotics that attack dangerous bacteria in a powerful new way, overcoming current drug resistance while sparing the gut microbiome.
“The biggest takeaway is the double-selective component,” said co-lead author Kristen A. Muñoz, PhD, who performed the research as a doctoral student at University of Illinois at Urbana-Champaign (UIUC). “We were able to develop a drug that not only targets problematic pathogens, but because it is selective for these pathogens only, we can spare the good bacteria and preserve the integrity of the microbiome.”
The drug goes after Gram-negative bacteria — pathogens responsible for debilitating and even fatal infections like gastroenteritis, urinary tract infections, pneumonia, sepsis, and cholera. The arsenal of antibiotics against them is old, with no new classes specifically targeting these bacteria coming on the market since 1968.
Many of these bugs have become resistant to one or more antibiotics, with deadly consequences. And antibiotics against them can also wipe out beneficial gut bacteria, allowing serious secondary infections to flare up.
In a study published in Nature, the drug lolamicin knocked out or reduced 130 strains of antibiotic-resistant Gram-negative bacteria in cell cultures. It also successfully treated drug-resistant bloodstream infections and pneumonia in mice while sparing their gut microbiome.
With their microbiomes intact, the mice then fought off secondary infection with Clostridioides difficile (a leading cause of opportunistic and sometimes fatal infections in US health care facilities), while mice treated with other compounds that damaged their microbiome succumbed.
How It Works
Like a well-built medieval castle, Gram-negative bacteria are encased in two protective walls, or membranes. Dr. Muñoz and her team at UIUC set out to breach this defense by finding compounds that hinder the “Lol system,” which ferries lipoproteins between them.
From one compound they constructed lolamicin, which can stop Gram-negative pathogens — with little effect on Gram-negative beneficial bacteria and no effect on Gram-positive bacteria.
“Gram-positive bacteria do not have an outer membrane, so they do not possess the Lol system,” Dr. Muñoz said. “When we compared the sequences of the Lol system in certain Gram-negative pathogens to Gram-negative commensal [beneficial] gut bacteria, we saw that the Lol systems were pretty different.”
Tossing a monkey wrench into the Lol system may be the study’s biggest contribution to future antibiotic development, said Kim Lewis, PhD, professor of Biology and director of Antimicrobial Discovery Center at Northeastern University, Boston, who has discovered several antibiotics now in preclinical research. One, darobactin, targets Gram-negative bugs without affecting the gut microbiome. Another, teixobactin, takes down Gram-positive bacteria without causing drug resistance.
“Lolamicin hits a novel target. I would say that’s the most significant study finding,” said Dr. Lewis, who was not involved in the study. “That is rare. If you look at antibiotics introduced since 1968, they have been modifications of existing antibiotics or, rarely, new chemically but hitting the same proven targets. This one hits something properly new, and [that’s] what I found perhaps the most original and interesting.”
Kirk E. Hevener, PharmD, PhD, associate professor of Pharmaceutical Sciences at the University of Tennessee Health Science Center, Memphis, Tennessee, agreed. (Dr. Hevener also was not involved in the study.) “Lolamicin works by targeting a unique Gram-negative transport system. No currently approved antibacterials work in this way, meaning it potentially represents the first of a new class of antibacterials with narrow-spectrum Gram-negative activity and low gastrointestinal disturbance,” said Dr. Hevener, whose research looks at new antimicrobial drug targets.
The UIUC researchers noted that lolamicin has one drawback: Bacteria frequently developed resistance to it. But in future work, it could be tweaked, combined with other antibiotics, or used as a template for finding other Lol system attackers, they said.
“There is still a good amount of work cut out for us in terms of assessing the clinical translatability of lolamicin, but we are hopeful for the future of this drug,” Dr. Muñoz said.
Addressing a Dire Need
Bringing such a drug to market — from discovery to Food and Drug Administration approval — could take more than a decade, said Dr. Hevener. And new agents, especially for Gram-negative bugs, are sorely needed.
Not only do these bacteria shield themselves with a double membrane but they also “have more complex resistance mechanisms including special pumps that can remove antibacterial drugs from the cell before they can be effective,” Dr. Hevener said.
As a result, drug-resistant Gram-negative bacteria are making treatment of severe infections such as sepsis and pneumonia in health care settings difficult.
Bloodstream infections with drug-resistant Klebsiella pneumoniae have a 40% mortality rate, Dr. Lewis said. And microbiome damage caused by antibiotics is also widespread and deadly, wiping out communities of helpful, protective gut bacteria. That contributes to over half of the C. difficile infections that affect 500,000 people and kill 30,000 a year in the United States.
“Our arsenal of antibacterials that can be used to treat Gram-negative infections is dangerously low,” Dr. Hevener said. “Research will always be needed to develop new antibacterials with novel mechanisms of activity that can bypass bacterial resistance mechanisms.”
A version of this article appeared on Medscape.com.
Gene Tests Could Predict if a Drug Will Work for a Patient
What if there were tests that could tell you whether the following drugs were a good match for your patients: Antidepressants, statins, painkillers, anticlotting medicines, chemotherapy agents, HIV treatments, organ transplant antirejection drugs, proton pump inhibitors for heartburn, and more?
That’s quite a list. And that’s pharmacogenetics, testing patients for genetic differences that affect how well a given drug will work for them and what kind of side effects to expect.
“About 9 out of 10 people will have a genetic difference in their DNA that can impact how they respond to common medications,” said Emily J. Cicali, PharmD, a clinical associate at the University of Florida College of Pharmacy, Gainesville.
Dr. Cicali is the clinical director of UF Health’s MyRx, a virtual program that gives Florida and New Jersey residents access to pharmacogenetic (PGx) tests plus expert interpretation by the health system’s pharmacists. Genetic factors are thought to contribute to about 25% or more of inappropriate drug responses or adverse events, said Kristin Wiisanen, PharmD, dean of the College of Pharmacy at Rosalind Franklin University of Medicine and Science in North Chicago.
Dr. Cicali said.
Through a cheek swab or blood sample, the MyRx program — and a growing number of health system programs, doctors’ offices, and home tests available across the United States — gives consumers a window on inherited gene variants that can affect how their body activates, metabolizes, and clears away medications from a long list of widely used drugs.
Why PGx Tests Can Have a Big Impact
These tests work by looking for genes that control drug metabolism.
“You have several different drug-metabolizing enzymes in your liver,” Dr. Cicali explained. “Pharmacogenetic tests look for gene variants that encode for these enzymes. If you’re an ultrarapid metabolizer, you have more of the enzymes that metabolize certain drugs, and there could be a risk the drug won’t work well because it doesn’t stay in the body long enough. On the other end of the spectrum, poor metabolizers have low levels of enzymes that affect certain drugs, so the drugs hang around longer and cause side effects.”
While pharmacogenetics is still considered an emerging science, it’s becoming more mainstream as test prices drop, insurance coverage expands, and an explosion of new research boosts understanding of gene-drug interactions, Dr. Wiisanen said.
Politicians are trying to extend its reach, too. The Right Drug Dose Now Act of 2024, introduced in Congress in late March, aims to accelerate the use of PGx by boosting public awareness and by inserting PGx test results into consumers’ electronic health records. (Though a similar bill died in a US House subcommittee in 2023.)
“The use of pharmacogenetic data to guide prescribing is growing rapidly,” Dr. Wiisanen said. “It’s becoming a routine part of drug therapy for many medications.”
What the Research Shows
When researchers sequenced the DNA of more than 10,000 Mayo Clinic patients, they made a discovery that might surprise many Americans: Gene variants that affect the effectiveness and safety of widely used drugs are not rare glitches. More than 99% of study participants had at least one. And 79% had three or more.
The Mayo-Baylor RIGHT 10K Study — one of the largest PGx studies ever conducted in the United States — looked at 77 gene variants, most involved with drug metabolism in the liver. Researchers focused closely on 13 with extensively studied, gene-based prescribing recommendations for 21 drugs including antidepressants, statins, pain killers, anticlotting medications for heart conditions, HIV treatments, chemotherapy agents, and antirejection drugs for organ transplants.
When researchers added participants’ genetic data to their electronic health records, they also sent semi-urgent alerts, which are alerts with the potential for severe harm, to the clinicians of 61 study volunteers. Over half changed patients’ drugs or doses.
The changes made a difference. One participant taking the pain drug tramadol turned out to be a poor metabolizer and was having dizzy spells because blood levels of the drug stayed high for long periods. Stopping tramadol stopped the dizziness. A participant taking escitalopram plus bupropion for major depression found out that the combo was likely ineffective because they metabolized escitalopram rapidly. A switch to a higher dose of bupropion alone put their depression into full remission.
“So many factors play into how you respond to medications,” said Mayo Clinic pharmacogenomics pharmacist Jessica Wright, PharmD, BCACP, one of the study authors. “Genetics is one of those pieces. Pharmacogenetic testing can reveal things that clinicians may not have been aware of or could help explain a patient’s exaggerated side effect.”
Pharmacogenetics is also called pharmacogenomics. The terms are often used interchangeably, even among PGx pharmacists, though the first refers to how individual genes influence drug response and the second to the effects of multiple genes, said Kelly E. Caudle, PharmD, PhD, an associate member of the Department of Pharmacy and Pharmaceutical Sciences at St. Jude Children’s Research Hospital in Memphis, Tennessee. Dr. Caudle is also co-principal investigator and director of the National Institutes of Health (NIH)-funded Clinical Pharmacogenetics Implementation Consortium (CPIC). The group creates, publishes, and posts evidence-based clinical practice guidelines for drugs with well-researched PGx influences.
By any name, PGx may help explain, predict, and sidestep unpredictable responses to a variety of drugs:
- In a 2023 multicenter study of 6944 people from seven European countries in The Lancet, those given customized drug treatments based on a 12-gene PGx panel had 30% fewer side effects than those who didn’t get this personalized prescribing. People in the study were being treated for cancer, heart disease, and mental health issues, among other conditions.
- In a 2023 from China’s Tongji University, Shanghai, of 650 survivors of strokes and transient ischemic attacks, those whose antiplatelet drugs (such as clopidogrel) were customized based on PGx testing had a lower risk for stroke and other vascular events in the next 90 days. The study was published in Frontiers in Pharmacology.
- In a University of Pennsylvania of 1944 adults with major depression, published in the Journal of the American Medical Association, those whose antidepressants were guided by PGx test results were 28% more likely to go into remission during the first 24 weeks of treatment than those in a control group. But by 24 weeks, equal numbers were in remission. A 2023 Chinese of 11 depression studies, published in BMC Psychiatry, came to a similar conclusion: PGx-guided antidepressant prescriptions may help people feel better quicker, perhaps by avoiding some of the usual trial-and-error of different depression drugs.
PGx checks are already strongly recommended or considered routine before some medications are prescribed. These include abacavir (Ziagen), an antiviral treatment for HIV that can have severe side effects in people with one gene variant.
The US Food and Drug Administration (FDA) recommends genetic testing for people with colon cancer before starting the drug irinotecan (Camptosar), which can cause severe diarrhea and raise infection risk in people with a gene variant that slows the drug’s elimination from the body.
Genetic testing is also recommended by the FDA for people with acute lymphoblastic leukemia before receiving the chemotherapy drug mercaptopurine (Purinethol) because a gene variant that affects drug processing can trigger serious side effects and raise the risk for infection at standard dosages.
“One of the key benefits of pharmacogenomic testing is in preventing adverse drug reactions,” Dr. Wiisanen said. “Testing of the thiopurine methyltransferase enzyme to guide dosing with 6-mercaptopurine or azathioprine can help prevent myelosuppression, a serious adverse drug reaction caused by lower production of blood cells in bone marrow.”
When, Why, and How to Test
“A family doctor should consider a PGx test if a patient is planning on taking a medication for which there is a CPIC guideline with a dosing recommendation,” said Teri Klein, PhD, professor of biomedical data science at Stanford University in California, and principal investigator at PharmGKB, an online resource funded by the NIH that provides information for healthcare practitioners, researchers, and consumers about PGx. Affiliated with CPIC, it’s based at Stanford University.
You might also consider it for patients already on a drug who are “not responding or experiencing side effects,” Dr. Caudle said.
Here’s how four PGx experts suggest consumers and physicians approach this option.
Find a Test
More than a dozen PGx tests are on the market — some only a provider can order, others a consumer can order after a review by their provider or by a provider from the testing company. Some of the tests (using saliva) may be administered at home, while blood tests are done in a doctor’s office or laboratory. Companies that offer the tests include ARUP Laboratories, Genomind, Labcorp, Mayo Clinic Laboratories, Myriad Neuroscience, Precision Sciences Inc., Tempus, and OneOme, but there are many others online. (Keep in mind that many laboratories offer “lab-developed tests” — created for use in a single laboratory — but these can be harder to verify. “The FDA regulates pharmacogenomic testing in laboratories,” Dr. Wiisanen said, “but many of the regulatory parameters are still being defined.”)
Because PGx is so new, there is no official list of recommended tests. So you’ll have to do a little homework. You can check that the laboratory is accredited by searching for it in the NIH Genetic Testing Laboratory Registry database. Beyond that, you’ll have to consult other evidence-based resources to confirm that the drug you’re interested in has research-backed data about specific gene variants (alleles) that affect metabolism as well as research-based clinical guidelines for using PGx results to make prescribing decisions.
The CPIC’s guidelines include dosing and alternate drug recommendations for more than 100 antidepressants, chemotherapy drugs, the antiplatelet and anticlotting drugs clopidogrel and warfarin, local anesthetics, antivirals and antibacterials, pain killers and anti-inflammatory drugs, and some cholesterol-lowering statins such as lovastatin and fluvastatin.
For help figuring out if a test looks for the right gene variants, Dr. Caudle and Dr. Wright recommended checking with the Association for Molecular Pathology’s website. The group published a brief list of best practices for pharmacogenomic testing in 2019. And it keeps a list of gene variants (alleles) that should be included in tests. Clinical guidelines from the CPIC and other groups, available on PharmGKB’s website, also list gene variants that affect the metabolism of the drug.
Consider Cost
The price tag for a test is typically several hundred dollars — but it can run as high as $1000-$2500. And health insurance doesn’t always pick up the tab.
In a 2023 University of Florida study of more than 1000 insurance claims for PGx testing, the number reimbursed varied from 72% for a pain diagnosis to 52% for cardiology to 46% for psychiatry.
Medicare covers some PGx testing when a consumer and their providers meet certain criteria, including whether a drug being considered has a significant gene-drug interaction. California’s Medi-Cal health insurance program covers PGx as do Medicaid programs in some states, including Arkansas and Rhode Island. You can find state-by-state coverage information on the Genetics Policy Hub’s website.
Understand the Results
As more insurers cover PGx, Dr. Klein and Dr. Wiisanen say the field will grow and more providers will use it to inform prescribing. But some health systems aren’t waiting.
In addition to UF Health’s MyRx, PGx is part of personalized medicine programs at the University of Pennsylvania in Philadelphia, Endeavor Health in Chicago, the Mayo Clinic, the University of California, San Francisco, Sanford Health in Sioux Falls, South Dakota, and St. Jude Children’s Research Hospital in Memphis, Tennessee.
Beyond testing, they offer a very useful service: A consult with a pharmacogenetics pharmacist to review the results and explain what they mean for a consumer’s current and future medications.
Physicians and curious consumers can also consult CPIC’s guidelines, which give recommendations about how to interpret the results of a PGx test, said Dr. Klein, a co-principal investigator at CPIC. CPIC has a grading system for both the evidence that supports the recommendation (high, moderate, or weak) and the recommendation itself (strong, moderate, or optional).
Currently, labeling for 456 prescription drugs sold in the United States includes some type of PGx information, according to the FDA’s Table of Pharmacogenomic Biomarkers in Drug Labeling and an annotated guide from PharmGKB.
Just 108 drug labels currently tell doctors and patients what to do with the information — such as requiring or suggesting testing or offering prescribing recommendations, according to PharmGKB. In contrast, PharmGKB’s online resources include evidence-based clinical guidelines for 201 drugs from CPIC and from professional PGx societies in the Netherlands, Canada, France, and elsewhere.
Consumers and physicians can also look for a pharmacist with pharmacogenetics training in their area or through a nearby medical center to learn more, Dr. Wright suggested. And while consumers can test without working with their own physician, the experts advise against it. Don’t stop or change the dose of medications you already take on your own, they say . And do work with your primary care practitioner or specialist to get tested and understand how the results fit into the bigger picture of how your body responds to your medications.
A version of this article appeared on Medscape.com.
What if there were tests that could tell you whether the following drugs were a good match for your patients: Antidepressants, statins, painkillers, anticlotting medicines, chemotherapy agents, HIV treatments, organ transplant antirejection drugs, proton pump inhibitors for heartburn, and more?
That’s quite a list. And that’s pharmacogenetics, testing patients for genetic differences that affect how well a given drug will work for them and what kind of side effects to expect.
“About 9 out of 10 people will have a genetic difference in their DNA that can impact how they respond to common medications,” said Emily J. Cicali, PharmD, a clinical associate at the University of Florida College of Pharmacy, Gainesville.
Dr. Cicali is the clinical director of UF Health’s MyRx, a virtual program that gives Florida and New Jersey residents access to pharmacogenetic (PGx) tests plus expert interpretation by the health system’s pharmacists. Genetic factors are thought to contribute to about 25% or more of inappropriate drug responses or adverse events, said Kristin Wiisanen, PharmD, dean of the College of Pharmacy at Rosalind Franklin University of Medicine and Science in North Chicago.
Dr. Cicali said.
Through a cheek swab or blood sample, the MyRx program — and a growing number of health system programs, doctors’ offices, and home tests available across the United States — gives consumers a window on inherited gene variants that can affect how their body activates, metabolizes, and clears away medications from a long list of widely used drugs.
Why PGx Tests Can Have a Big Impact
These tests work by looking for genes that control drug metabolism.
“You have several different drug-metabolizing enzymes in your liver,” Dr. Cicali explained. “Pharmacogenetic tests look for gene variants that encode for these enzymes. If you’re an ultrarapid metabolizer, you have more of the enzymes that metabolize certain drugs, and there could be a risk the drug won’t work well because it doesn’t stay in the body long enough. On the other end of the spectrum, poor metabolizers have low levels of enzymes that affect certain drugs, so the drugs hang around longer and cause side effects.”
While pharmacogenetics is still considered an emerging science, it’s becoming more mainstream as test prices drop, insurance coverage expands, and an explosion of new research boosts understanding of gene-drug interactions, Dr. Wiisanen said.
Politicians are trying to extend its reach, too. The Right Drug Dose Now Act of 2024, introduced in Congress in late March, aims to accelerate the use of PGx by boosting public awareness and by inserting PGx test results into consumers’ electronic health records. (Though a similar bill died in a US House subcommittee in 2023.)
“The use of pharmacogenetic data to guide prescribing is growing rapidly,” Dr. Wiisanen said. “It’s becoming a routine part of drug therapy for many medications.”
What the Research Shows
When researchers sequenced the DNA of more than 10,000 Mayo Clinic patients, they made a discovery that might surprise many Americans: Gene variants that affect the effectiveness and safety of widely used drugs are not rare glitches. More than 99% of study participants had at least one. And 79% had three or more.
The Mayo-Baylor RIGHT 10K Study — one of the largest PGx studies ever conducted in the United States — looked at 77 gene variants, most involved with drug metabolism in the liver. Researchers focused closely on 13 with extensively studied, gene-based prescribing recommendations for 21 drugs including antidepressants, statins, pain killers, anticlotting medications for heart conditions, HIV treatments, chemotherapy agents, and antirejection drugs for organ transplants.
When researchers added participants’ genetic data to their electronic health records, they also sent semi-urgent alerts, which are alerts with the potential for severe harm, to the clinicians of 61 study volunteers. Over half changed patients’ drugs or doses.
The changes made a difference. One participant taking the pain drug tramadol turned out to be a poor metabolizer and was having dizzy spells because blood levels of the drug stayed high for long periods. Stopping tramadol stopped the dizziness. A participant taking escitalopram plus bupropion for major depression found out that the combo was likely ineffective because they metabolized escitalopram rapidly. A switch to a higher dose of bupropion alone put their depression into full remission.
“So many factors play into how you respond to medications,” said Mayo Clinic pharmacogenomics pharmacist Jessica Wright, PharmD, BCACP, one of the study authors. “Genetics is one of those pieces. Pharmacogenetic testing can reveal things that clinicians may not have been aware of or could help explain a patient’s exaggerated side effect.”
Pharmacogenetics is also called pharmacogenomics. The terms are often used interchangeably, even among PGx pharmacists, though the first refers to how individual genes influence drug response and the second to the effects of multiple genes, said Kelly E. Caudle, PharmD, PhD, an associate member of the Department of Pharmacy and Pharmaceutical Sciences at St. Jude Children’s Research Hospital in Memphis, Tennessee. Dr. Caudle is also co-principal investigator and director of the National Institutes of Health (NIH)-funded Clinical Pharmacogenetics Implementation Consortium (CPIC). The group creates, publishes, and posts evidence-based clinical practice guidelines for drugs with well-researched PGx influences.
By any name, PGx may help explain, predict, and sidestep unpredictable responses to a variety of drugs:
- In a 2023 multicenter study of 6944 people from seven European countries in The Lancet, those given customized drug treatments based on a 12-gene PGx panel had 30% fewer side effects than those who didn’t get this personalized prescribing. People in the study were being treated for cancer, heart disease, and mental health issues, among other conditions.
- In a 2023 from China’s Tongji University, Shanghai, of 650 survivors of strokes and transient ischemic attacks, those whose antiplatelet drugs (such as clopidogrel) were customized based on PGx testing had a lower risk for stroke and other vascular events in the next 90 days. The study was published in Frontiers in Pharmacology.
- In a University of Pennsylvania of 1944 adults with major depression, published in the Journal of the American Medical Association, those whose antidepressants were guided by PGx test results were 28% more likely to go into remission during the first 24 weeks of treatment than those in a control group. But by 24 weeks, equal numbers were in remission. A 2023 Chinese of 11 depression studies, published in BMC Psychiatry, came to a similar conclusion: PGx-guided antidepressant prescriptions may help people feel better quicker, perhaps by avoiding some of the usual trial-and-error of different depression drugs.
PGx checks are already strongly recommended or considered routine before some medications are prescribed. These include abacavir (Ziagen), an antiviral treatment for HIV that can have severe side effects in people with one gene variant.
The US Food and Drug Administration (FDA) recommends genetic testing for people with colon cancer before starting the drug irinotecan (Camptosar), which can cause severe diarrhea and raise infection risk in people with a gene variant that slows the drug’s elimination from the body.
Genetic testing is also recommended by the FDA for people with acute lymphoblastic leukemia before receiving the chemotherapy drug mercaptopurine (Purinethol) because a gene variant that affects drug processing can trigger serious side effects and raise the risk for infection at standard dosages.
“One of the key benefits of pharmacogenomic testing is in preventing adverse drug reactions,” Dr. Wiisanen said. “Testing of the thiopurine methyltransferase enzyme to guide dosing with 6-mercaptopurine or azathioprine can help prevent myelosuppression, a serious adverse drug reaction caused by lower production of blood cells in bone marrow.”
When, Why, and How to Test
“A family doctor should consider a PGx test if a patient is planning on taking a medication for which there is a CPIC guideline with a dosing recommendation,” said Teri Klein, PhD, professor of biomedical data science at Stanford University in California, and principal investigator at PharmGKB, an online resource funded by the NIH that provides information for healthcare practitioners, researchers, and consumers about PGx. Affiliated with CPIC, it’s based at Stanford University.
You might also consider it for patients already on a drug who are “not responding or experiencing side effects,” Dr. Caudle said.
Here’s how four PGx experts suggest consumers and physicians approach this option.
Find a Test
More than a dozen PGx tests are on the market — some only a provider can order, others a consumer can order after a review by their provider or by a provider from the testing company. Some of the tests (using saliva) may be administered at home, while blood tests are done in a doctor’s office or laboratory. Companies that offer the tests include ARUP Laboratories, Genomind, Labcorp, Mayo Clinic Laboratories, Myriad Neuroscience, Precision Sciences Inc., Tempus, and OneOme, but there are many others online. (Keep in mind that many laboratories offer “lab-developed tests” — created for use in a single laboratory — but these can be harder to verify. “The FDA regulates pharmacogenomic testing in laboratories,” Dr. Wiisanen said, “but many of the regulatory parameters are still being defined.”)
Because PGx is so new, there is no official list of recommended tests. So you’ll have to do a little homework. You can check that the laboratory is accredited by searching for it in the NIH Genetic Testing Laboratory Registry database. Beyond that, you’ll have to consult other evidence-based resources to confirm that the drug you’re interested in has research-backed data about specific gene variants (alleles) that affect metabolism as well as research-based clinical guidelines for using PGx results to make prescribing decisions.
The CPIC’s guidelines include dosing and alternate drug recommendations for more than 100 antidepressants, chemotherapy drugs, the antiplatelet and anticlotting drugs clopidogrel and warfarin, local anesthetics, antivirals and antibacterials, pain killers and anti-inflammatory drugs, and some cholesterol-lowering statins such as lovastatin and fluvastatin.
For help figuring out if a test looks for the right gene variants, Dr. Caudle and Dr. Wright recommended checking with the Association for Molecular Pathology’s website. The group published a brief list of best practices for pharmacogenomic testing in 2019. And it keeps a list of gene variants (alleles) that should be included in tests. Clinical guidelines from the CPIC and other groups, available on PharmGKB’s website, also list gene variants that affect the metabolism of the drug.
Consider Cost
The price tag for a test is typically several hundred dollars — but it can run as high as $1000-$2500. And health insurance doesn’t always pick up the tab.
In a 2023 University of Florida study of more than 1000 insurance claims for PGx testing, the number reimbursed varied from 72% for a pain diagnosis to 52% for cardiology to 46% for psychiatry.
Medicare covers some PGx testing when a consumer and their providers meet certain criteria, including whether a drug being considered has a significant gene-drug interaction. California’s Medi-Cal health insurance program covers PGx as do Medicaid programs in some states, including Arkansas and Rhode Island. You can find state-by-state coverage information on the Genetics Policy Hub’s website.
Understand the Results
As more insurers cover PGx, Dr. Klein and Dr. Wiisanen say the field will grow and more providers will use it to inform prescribing. But some health systems aren’t waiting.
In addition to UF Health’s MyRx, PGx is part of personalized medicine programs at the University of Pennsylvania in Philadelphia, Endeavor Health in Chicago, the Mayo Clinic, the University of California, San Francisco, Sanford Health in Sioux Falls, South Dakota, and St. Jude Children’s Research Hospital in Memphis, Tennessee.
Beyond testing, they offer a very useful service: A consult with a pharmacogenetics pharmacist to review the results and explain what they mean for a consumer’s current and future medications.
Physicians and curious consumers can also consult CPIC’s guidelines, which give recommendations about how to interpret the results of a PGx test, said Dr. Klein, a co-principal investigator at CPIC. CPIC has a grading system for both the evidence that supports the recommendation (high, moderate, or weak) and the recommendation itself (strong, moderate, or optional).
Currently, labeling for 456 prescription drugs sold in the United States includes some type of PGx information, according to the FDA’s Table of Pharmacogenomic Biomarkers in Drug Labeling and an annotated guide from PharmGKB.
Just 108 drug labels currently tell doctors and patients what to do with the information — such as requiring or suggesting testing or offering prescribing recommendations, according to PharmGKB. In contrast, PharmGKB’s online resources include evidence-based clinical guidelines for 201 drugs from CPIC and from professional PGx societies in the Netherlands, Canada, France, and elsewhere.
Consumers and physicians can also look for a pharmacist with pharmacogenetics training in their area or through a nearby medical center to learn more, Dr. Wright suggested. And while consumers can test without working with their own physician, the experts advise against it. Don’t stop or change the dose of medications you already take on your own, they say . And do work with your primary care practitioner or specialist to get tested and understand how the results fit into the bigger picture of how your body responds to your medications.
A version of this article appeared on Medscape.com.
What if there were tests that could tell you whether the following drugs were a good match for your patients: Antidepressants, statins, painkillers, anticlotting medicines, chemotherapy agents, HIV treatments, organ transplant antirejection drugs, proton pump inhibitors for heartburn, and more?
That’s quite a list. And that’s pharmacogenetics, testing patients for genetic differences that affect how well a given drug will work for them and what kind of side effects to expect.
“About 9 out of 10 people will have a genetic difference in their DNA that can impact how they respond to common medications,” said Emily J. Cicali, PharmD, a clinical associate at the University of Florida College of Pharmacy, Gainesville.
Dr. Cicali is the clinical director of UF Health’s MyRx, a virtual program that gives Florida and New Jersey residents access to pharmacogenetic (PGx) tests plus expert interpretation by the health system’s pharmacists. Genetic factors are thought to contribute to about 25% or more of inappropriate drug responses or adverse events, said Kristin Wiisanen, PharmD, dean of the College of Pharmacy at Rosalind Franklin University of Medicine and Science in North Chicago.
Dr. Cicali said.
Through a cheek swab or blood sample, the MyRx program — and a growing number of health system programs, doctors’ offices, and home tests available across the United States — gives consumers a window on inherited gene variants that can affect how their body activates, metabolizes, and clears away medications from a long list of widely used drugs.
Why PGx Tests Can Have a Big Impact
These tests work by looking for genes that control drug metabolism.
“You have several different drug-metabolizing enzymes in your liver,” Dr. Cicali explained. “Pharmacogenetic tests look for gene variants that encode for these enzymes. If you’re an ultrarapid metabolizer, you have more of the enzymes that metabolize certain drugs, and there could be a risk the drug won’t work well because it doesn’t stay in the body long enough. On the other end of the spectrum, poor metabolizers have low levels of enzymes that affect certain drugs, so the drugs hang around longer and cause side effects.”
While pharmacogenetics is still considered an emerging science, it’s becoming more mainstream as test prices drop, insurance coverage expands, and an explosion of new research boosts understanding of gene-drug interactions, Dr. Wiisanen said.
Politicians are trying to extend its reach, too. The Right Drug Dose Now Act of 2024, introduced in Congress in late March, aims to accelerate the use of PGx by boosting public awareness and by inserting PGx test results into consumers’ electronic health records. (Though a similar bill died in a US House subcommittee in 2023.)
“The use of pharmacogenetic data to guide prescribing is growing rapidly,” Dr. Wiisanen said. “It’s becoming a routine part of drug therapy for many medications.”
What the Research Shows
When researchers sequenced the DNA of more than 10,000 Mayo Clinic patients, they made a discovery that might surprise many Americans: Gene variants that affect the effectiveness and safety of widely used drugs are not rare glitches. More than 99% of study participants had at least one. And 79% had three or more.
The Mayo-Baylor RIGHT 10K Study — one of the largest PGx studies ever conducted in the United States — looked at 77 gene variants, most involved with drug metabolism in the liver. Researchers focused closely on 13 with extensively studied, gene-based prescribing recommendations for 21 drugs including antidepressants, statins, pain killers, anticlotting medications for heart conditions, HIV treatments, chemotherapy agents, and antirejection drugs for organ transplants.
When researchers added participants’ genetic data to their electronic health records, they also sent semi-urgent alerts, which are alerts with the potential for severe harm, to the clinicians of 61 study volunteers. Over half changed patients’ drugs or doses.
The changes made a difference. One participant taking the pain drug tramadol turned out to be a poor metabolizer and was having dizzy spells because blood levels of the drug stayed high for long periods. Stopping tramadol stopped the dizziness. A participant taking escitalopram plus bupropion for major depression found out that the combo was likely ineffective because they metabolized escitalopram rapidly. A switch to a higher dose of bupropion alone put their depression into full remission.
“So many factors play into how you respond to medications,” said Mayo Clinic pharmacogenomics pharmacist Jessica Wright, PharmD, BCACP, one of the study authors. “Genetics is one of those pieces. Pharmacogenetic testing can reveal things that clinicians may not have been aware of or could help explain a patient’s exaggerated side effect.”
Pharmacogenetics is also called pharmacogenomics. The terms are often used interchangeably, even among PGx pharmacists, though the first refers to how individual genes influence drug response and the second to the effects of multiple genes, said Kelly E. Caudle, PharmD, PhD, an associate member of the Department of Pharmacy and Pharmaceutical Sciences at St. Jude Children’s Research Hospital in Memphis, Tennessee. Dr. Caudle is also co-principal investigator and director of the National Institutes of Health (NIH)-funded Clinical Pharmacogenetics Implementation Consortium (CPIC). The group creates, publishes, and posts evidence-based clinical practice guidelines for drugs with well-researched PGx influences.
By any name, PGx may help explain, predict, and sidestep unpredictable responses to a variety of drugs:
- In a 2023 multicenter study of 6944 people from seven European countries in The Lancet, those given customized drug treatments based on a 12-gene PGx panel had 30% fewer side effects than those who didn’t get this personalized prescribing. People in the study were being treated for cancer, heart disease, and mental health issues, among other conditions.
- In a 2023 from China’s Tongji University, Shanghai, of 650 survivors of strokes and transient ischemic attacks, those whose antiplatelet drugs (such as clopidogrel) were customized based on PGx testing had a lower risk for stroke and other vascular events in the next 90 days. The study was published in Frontiers in Pharmacology.
- In a University of Pennsylvania of 1944 adults with major depression, published in the Journal of the American Medical Association, those whose antidepressants were guided by PGx test results were 28% more likely to go into remission during the first 24 weeks of treatment than those in a control group. But by 24 weeks, equal numbers were in remission. A 2023 Chinese of 11 depression studies, published in BMC Psychiatry, came to a similar conclusion: PGx-guided antidepressant prescriptions may help people feel better quicker, perhaps by avoiding some of the usual trial-and-error of different depression drugs.
PGx checks are already strongly recommended or considered routine before some medications are prescribed. These include abacavir (Ziagen), an antiviral treatment for HIV that can have severe side effects in people with one gene variant.
The US Food and Drug Administration (FDA) recommends genetic testing for people with colon cancer before starting the drug irinotecan (Camptosar), which can cause severe diarrhea and raise infection risk in people with a gene variant that slows the drug’s elimination from the body.
Genetic testing is also recommended by the FDA for people with acute lymphoblastic leukemia before receiving the chemotherapy drug mercaptopurine (Purinethol) because a gene variant that affects drug processing can trigger serious side effects and raise the risk for infection at standard dosages.
“One of the key benefits of pharmacogenomic testing is in preventing adverse drug reactions,” Dr. Wiisanen said. “Testing of the thiopurine methyltransferase enzyme to guide dosing with 6-mercaptopurine or azathioprine can help prevent myelosuppression, a serious adverse drug reaction caused by lower production of blood cells in bone marrow.”
When, Why, and How to Test
“A family doctor should consider a PGx test if a patient is planning on taking a medication for which there is a CPIC guideline with a dosing recommendation,” said Teri Klein, PhD, professor of biomedical data science at Stanford University in California, and principal investigator at PharmGKB, an online resource funded by the NIH that provides information for healthcare practitioners, researchers, and consumers about PGx. Affiliated with CPIC, it’s based at Stanford University.
You might also consider it for patients already on a drug who are “not responding or experiencing side effects,” Dr. Caudle said.
Here’s how four PGx experts suggest consumers and physicians approach this option.
Find a Test
More than a dozen PGx tests are on the market — some only a provider can order, others a consumer can order after a review by their provider or by a provider from the testing company. Some of the tests (using saliva) may be administered at home, while blood tests are done in a doctor’s office or laboratory. Companies that offer the tests include ARUP Laboratories, Genomind, Labcorp, Mayo Clinic Laboratories, Myriad Neuroscience, Precision Sciences Inc., Tempus, and OneOme, but there are many others online. (Keep in mind that many laboratories offer “lab-developed tests” — created for use in a single laboratory — but these can be harder to verify. “The FDA regulates pharmacogenomic testing in laboratories,” Dr. Wiisanen said, “but many of the regulatory parameters are still being defined.”)
Because PGx is so new, there is no official list of recommended tests. So you’ll have to do a little homework. You can check that the laboratory is accredited by searching for it in the NIH Genetic Testing Laboratory Registry database. Beyond that, you’ll have to consult other evidence-based resources to confirm that the drug you’re interested in has research-backed data about specific gene variants (alleles) that affect metabolism as well as research-based clinical guidelines for using PGx results to make prescribing decisions.
The CPIC’s guidelines include dosing and alternate drug recommendations for more than 100 antidepressants, chemotherapy drugs, the antiplatelet and anticlotting drugs clopidogrel and warfarin, local anesthetics, antivirals and antibacterials, pain killers and anti-inflammatory drugs, and some cholesterol-lowering statins such as lovastatin and fluvastatin.
For help figuring out if a test looks for the right gene variants, Dr. Caudle and Dr. Wright recommended checking with the Association for Molecular Pathology’s website. The group published a brief list of best practices for pharmacogenomic testing in 2019. And it keeps a list of gene variants (alleles) that should be included in tests. Clinical guidelines from the CPIC and other groups, available on PharmGKB’s website, also list gene variants that affect the metabolism of the drug.
Consider Cost
The price tag for a test is typically several hundred dollars — but it can run as high as $1000-$2500. And health insurance doesn’t always pick up the tab.
In a 2023 University of Florida study of more than 1000 insurance claims for PGx testing, the number reimbursed varied from 72% for a pain diagnosis to 52% for cardiology to 46% for psychiatry.
Medicare covers some PGx testing when a consumer and their providers meet certain criteria, including whether a drug being considered has a significant gene-drug interaction. California’s Medi-Cal health insurance program covers PGx as do Medicaid programs in some states, including Arkansas and Rhode Island. You can find state-by-state coverage information on the Genetics Policy Hub’s website.
Understand the Results
As more insurers cover PGx, Dr. Klein and Dr. Wiisanen say the field will grow and more providers will use it to inform prescribing. But some health systems aren’t waiting.
In addition to UF Health’s MyRx, PGx is part of personalized medicine programs at the University of Pennsylvania in Philadelphia, Endeavor Health in Chicago, the Mayo Clinic, the University of California, San Francisco, Sanford Health in Sioux Falls, South Dakota, and St. Jude Children’s Research Hospital in Memphis, Tennessee.
Beyond testing, they offer a very useful service: A consult with a pharmacogenetics pharmacist to review the results and explain what they mean for a consumer’s current and future medications.
Physicians and curious consumers can also consult CPIC’s guidelines, which give recommendations about how to interpret the results of a PGx test, said Dr. Klein, a co-principal investigator at CPIC. CPIC has a grading system for both the evidence that supports the recommendation (high, moderate, or weak) and the recommendation itself (strong, moderate, or optional).
Currently, labeling for 456 prescription drugs sold in the United States includes some type of PGx information, according to the FDA’s Table of Pharmacogenomic Biomarkers in Drug Labeling and an annotated guide from PharmGKB.
Just 108 drug labels currently tell doctors and patients what to do with the information — such as requiring or suggesting testing or offering prescribing recommendations, according to PharmGKB. In contrast, PharmGKB’s online resources include evidence-based clinical guidelines for 201 drugs from CPIC and from professional PGx societies in the Netherlands, Canada, France, and elsewhere.
Consumers and physicians can also look for a pharmacist with pharmacogenetics training in their area or through a nearby medical center to learn more, Dr. Wright suggested. And while consumers can test without working with their own physician, the experts advise against it. Don’t stop or change the dose of medications you already take on your own, they say . And do work with your primary care practitioner or specialist to get tested and understand how the results fit into the bigger picture of how your body responds to your medications.
A version of this article appeared on Medscape.com.
Why a New Inhalable Lung Cancer Treatment Is So Promising
Cells in the human body chat with each other all the time. One major way they communicate is by releasing tiny spheres called exosomes. These carry fats, proteins, and genetic material that help regulate everything from pregnancy and immune responses to heart health and kidney function.
“Exosomes work like text messages between cells , sending and receiving information,” said lead researcher Ke Cheng, PhD, professor of biomedical engineering at Columbia. “The significance of this study is that exosomes can bring mRNA-based treatment to lung cancer cells locally, unlike systemic chemotherapy that can have side effects throughout the body. And inhalation is totally noninvasive. You don’t need a nurse to use an IV needle to pierce your skin.”
Dr. Cheng expects a human trial could launch within 5 years. For now, his study is attracting attention because it marks an advance in three areas of intense interest by researchers and biotech companies alike: Therapeutic uses of exosomes, inhalable treatments for lung conditions, and the safe delivery of powerful interleukin-12 (IL-12) immunotherapy.
Inside the Study
Dr. Cheng, who has been developing exosome and stem cell therapies for more than 15 years, and his lab team focused on lung cancer because the disease, often detected in later stages, “has a huge mortality rate,” he said. “Therapies have been suboptimal and leave the organ so damaged.”
He wanted to explore new alternatives to systemic treatments. Most are given intravenously, but Dr. Cheng thinks exosomes — also called extracellular vesicles (EVs) — could change that.
“One of the advantages of exosomes is that they are naturally secreted by the body or cultured cells,” he noted. “They have low toxicity and have multiple ways of getting their message into cells.”
The scientists borrowed an approach that captured public attention during the pandemic: Using messenger RNA, which directs cells to make proteins for tasks — including boosting immune response.
IL-12 has shown promise against cancer for decades, but early human trials triggered serious side effects and several deaths. Researchers are now trying new delivery methods that target tumor cells without affecting healthy tissue. Dr. Cheng’s team took a new approach, inserting mRNA for IL-12 into exosomes.
One aim of the study was to compare the effectiveness of inhaled exosomes vs inhaled liposomes, engineered fat droplets also under investigation as drug carriers. The team’s question: Which would work better at introducing IL-12 to the lungs to affect cancer, without triggering side effects?
After lab mice inhaled the particles through the nose, the researchers found that exosomes delivered more mRNA into cancer cells in the lungs and fought lung cancer with few side effects. Three days after treatment, researchers saw an influx of cancer-fighting T cells within tumors — with higher levels for exosome-based treatment. Plus, the exosomes led to more cancer-destroying nature killer cells and more monocytes, a sign of immune-system activation.
Researchers also found the treatment acted as a vaccine, training the immune system to battle newly introduced cancers. Little of the exosome-delivered drug escaped into the bloodstream, and the study found minimal side effects. Inhalation didn’t affect normal breathing, Dr. Cheng added.
The study’s use of inhaled exosomes makes it significant, said Raghu Kalluri, MD, PhD, professor and chair of the Department of Cancer Biology at MD Anderson Cancer Center. “This is an interesting study that explores the inhalable delivery of engineered EVs for the treatment of lung cancer and offers insights into focused delivery of EV-based drugs…with implications for diseases beyond cancer,” he said. Dr. Kalluri is also an exosome researcher.
New Frontiers
Once seen as a “quirky biological phenomenon” or just cellular trash, exosomes are now the subject of intense medical research for their potential as drug carriers, as treatments in their own right for everything from wound healing and pneumonia to heart attacks and bowel disorders, and as measurable biological markers that could lead to new tests for cancer and other conditions. One exosome-based prostate cancer test, the ExoDx Prostate Test, is already on the market.
The explosion in exosome research — the number of published studies has grown from just a handful in the early 1980s to more than 9000 — spotlights a particular focus on cancer. According to a 2021 paper in Annals of Oncology, clinical trials for exosomes in cancer treatments and tests far out-paces those for diabetes, heart disease, or neurologic conditions. Currently, 52 clinical trials using exosomes in cancer diagnosis or treatment have been completed, are underway, or are looking for participants, according to clinicaltrials.gov.
Dr. Cheng’s approach could also be used to deliver other drugs to the lungs and other organs via inhalation. “We’re testing inhalation for a different type of lung disease, acute lung injury,” Dr. Cheng said. Other potential targets include lung disorders like pulmonary hypertension. Inhaled exosomes could potentially reach the brain via the olfactory bulb or the heart as it receives oxygenated blood from the lungs.
Breathing in Medicine
So far, inhalable cancer treatments are not available outside research studies in the United States or Europe , said Remi Rosiere, PhD, a lecturer at the Université libre de Bruxelles in Brussels, Belgium, and chief scientific officer of InhaTarget Therapeutics, a company developing its own inhaled treatments for severe respiratory diseases. “Oncologists are very interested,” he said. “If you concentrate the drug on the tumor site, you can avoid distribution to the body.”
Early research into inhalable chemotherapy began in the 1960s but was unsuccessful because breathing equipment dispersed toxic cancer drugs into the air or delivered only small amounts to the lungs, he said.
New delivery techniques aim to change that. Dr. Rosiere’s company is starting a human trial of a dry powder inhaler with the chemotherapy drug cisplatin for lung cancer. Also in the pipeline is an immunotherapy treatment for lung cancer inserted in lipid nanoparticles, which are tiny fat particles similar to liposomes.
He said Dr. Cheng’s study shows the advantages of sending in exosomes. “The data are very persuasive,” Dr. Rosier said of the study. “Exosomes have a good safety profile and are able to remain in the lung for quite a long time. This prolongs exposure to the drug for greater effectiveness, without causing toxicities.”
Getting from a mouse study to a human trial will take time. “You need to understand this is very early stage,” Dr. Rosiere added. “There will be many challenges to overcome.”
One is purely practical: If the drug approaches human trials, he said, regulators will ask whether the exosomes can be produced in large quantities to meet the huge demand for new lung cancer treatments. “Lung cancer is the number one fatal cancer in the world,” Dr. Rosiere said.
A New Route for ‘Powerful’ Cancer Treatment
Meanwhile, the Columbia University study showed that inhalable exosomes are a unique delivery method for IL-12 — and could help solve a major problem that’s plagued this promising cancer treatment for decades.
Called “one of the most powerful immunotherapy agents ever discovered” in a 2022 literature review, IL-12 showed serious side effects that stalled research in the 1980s , sparking an ongoing search for new delivery methods that continues today. In 2022 and 2023, Big Pharma companies including AstraZenca, Moderna, and Bristol Myers Squib reduced their involvement with IL-12 treatment research, leaving the field open to smaller biotech companies working on a variety of drug-delivery approaches that could make IL-12 safe and effective in humans.
These include injecting it directly into tumors, encasing it in various types of particles, masking the drug so it is activated only in cancer cells, and using IL-12 mRNA, which essentially turns tumor cells into IL-12–producing factories. Another IL-12 mRNA drug, from Pittsburgh-based Krystal Biotech, received a fast-track designation from the US Food and Drug Administration in February 2024 for an inhaled lung cancer treatment that packages mRNA for IL-12 and IL-2 inside an engineered virus.
And of course, there is Dr. Cheng’s inhalable treatment, culminating decades of work across three burgeoning fields.
A version of this article appeared on Medscape.com.
Cells in the human body chat with each other all the time. One major way they communicate is by releasing tiny spheres called exosomes. These carry fats, proteins, and genetic material that help regulate everything from pregnancy and immune responses to heart health and kidney function.
“Exosomes work like text messages between cells , sending and receiving information,” said lead researcher Ke Cheng, PhD, professor of biomedical engineering at Columbia. “The significance of this study is that exosomes can bring mRNA-based treatment to lung cancer cells locally, unlike systemic chemotherapy that can have side effects throughout the body. And inhalation is totally noninvasive. You don’t need a nurse to use an IV needle to pierce your skin.”
Dr. Cheng expects a human trial could launch within 5 years. For now, his study is attracting attention because it marks an advance in three areas of intense interest by researchers and biotech companies alike: Therapeutic uses of exosomes, inhalable treatments for lung conditions, and the safe delivery of powerful interleukin-12 (IL-12) immunotherapy.
Inside the Study
Dr. Cheng, who has been developing exosome and stem cell therapies for more than 15 years, and his lab team focused on lung cancer because the disease, often detected in later stages, “has a huge mortality rate,” he said. “Therapies have been suboptimal and leave the organ so damaged.”
He wanted to explore new alternatives to systemic treatments. Most are given intravenously, but Dr. Cheng thinks exosomes — also called extracellular vesicles (EVs) — could change that.
“One of the advantages of exosomes is that they are naturally secreted by the body or cultured cells,” he noted. “They have low toxicity and have multiple ways of getting their message into cells.”
The scientists borrowed an approach that captured public attention during the pandemic: Using messenger RNA, which directs cells to make proteins for tasks — including boosting immune response.
IL-12 has shown promise against cancer for decades, but early human trials triggered serious side effects and several deaths. Researchers are now trying new delivery methods that target tumor cells without affecting healthy tissue. Dr. Cheng’s team took a new approach, inserting mRNA for IL-12 into exosomes.
One aim of the study was to compare the effectiveness of inhaled exosomes vs inhaled liposomes, engineered fat droplets also under investigation as drug carriers. The team’s question: Which would work better at introducing IL-12 to the lungs to affect cancer, without triggering side effects?
After lab mice inhaled the particles through the nose, the researchers found that exosomes delivered more mRNA into cancer cells in the lungs and fought lung cancer with few side effects. Three days after treatment, researchers saw an influx of cancer-fighting T cells within tumors — with higher levels for exosome-based treatment. Plus, the exosomes led to more cancer-destroying nature killer cells and more monocytes, a sign of immune-system activation.
Researchers also found the treatment acted as a vaccine, training the immune system to battle newly introduced cancers. Little of the exosome-delivered drug escaped into the bloodstream, and the study found minimal side effects. Inhalation didn’t affect normal breathing, Dr. Cheng added.
The study’s use of inhaled exosomes makes it significant, said Raghu Kalluri, MD, PhD, professor and chair of the Department of Cancer Biology at MD Anderson Cancer Center. “This is an interesting study that explores the inhalable delivery of engineered EVs for the treatment of lung cancer and offers insights into focused delivery of EV-based drugs…with implications for diseases beyond cancer,” he said. Dr. Kalluri is also an exosome researcher.
New Frontiers
Once seen as a “quirky biological phenomenon” or just cellular trash, exosomes are now the subject of intense medical research for their potential as drug carriers, as treatments in their own right for everything from wound healing and pneumonia to heart attacks and bowel disorders, and as measurable biological markers that could lead to new tests for cancer and other conditions. One exosome-based prostate cancer test, the ExoDx Prostate Test, is already on the market.
The explosion in exosome research — the number of published studies has grown from just a handful in the early 1980s to more than 9000 — spotlights a particular focus on cancer. According to a 2021 paper in Annals of Oncology, clinical trials for exosomes in cancer treatments and tests far out-paces those for diabetes, heart disease, or neurologic conditions. Currently, 52 clinical trials using exosomes in cancer diagnosis or treatment have been completed, are underway, or are looking for participants, according to clinicaltrials.gov.
Dr. Cheng’s approach could also be used to deliver other drugs to the lungs and other organs via inhalation. “We’re testing inhalation for a different type of lung disease, acute lung injury,” Dr. Cheng said. Other potential targets include lung disorders like pulmonary hypertension. Inhaled exosomes could potentially reach the brain via the olfactory bulb or the heart as it receives oxygenated blood from the lungs.
Breathing in Medicine
So far, inhalable cancer treatments are not available outside research studies in the United States or Europe , said Remi Rosiere, PhD, a lecturer at the Université libre de Bruxelles in Brussels, Belgium, and chief scientific officer of InhaTarget Therapeutics, a company developing its own inhaled treatments for severe respiratory diseases. “Oncologists are very interested,” he said. “If you concentrate the drug on the tumor site, you can avoid distribution to the body.”
Early research into inhalable chemotherapy began in the 1960s but was unsuccessful because breathing equipment dispersed toxic cancer drugs into the air or delivered only small amounts to the lungs, he said.
New delivery techniques aim to change that. Dr. Rosiere’s company is starting a human trial of a dry powder inhaler with the chemotherapy drug cisplatin for lung cancer. Also in the pipeline is an immunotherapy treatment for lung cancer inserted in lipid nanoparticles, which are tiny fat particles similar to liposomes.
He said Dr. Cheng’s study shows the advantages of sending in exosomes. “The data are very persuasive,” Dr. Rosier said of the study. “Exosomes have a good safety profile and are able to remain in the lung for quite a long time. This prolongs exposure to the drug for greater effectiveness, without causing toxicities.”
Getting from a mouse study to a human trial will take time. “You need to understand this is very early stage,” Dr. Rosiere added. “There will be many challenges to overcome.”
One is purely practical: If the drug approaches human trials, he said, regulators will ask whether the exosomes can be produced in large quantities to meet the huge demand for new lung cancer treatments. “Lung cancer is the number one fatal cancer in the world,” Dr. Rosiere said.
A New Route for ‘Powerful’ Cancer Treatment
Meanwhile, the Columbia University study showed that inhalable exosomes are a unique delivery method for IL-12 — and could help solve a major problem that’s plagued this promising cancer treatment for decades.
Called “one of the most powerful immunotherapy agents ever discovered” in a 2022 literature review, IL-12 showed serious side effects that stalled research in the 1980s , sparking an ongoing search for new delivery methods that continues today. In 2022 and 2023, Big Pharma companies including AstraZenca, Moderna, and Bristol Myers Squib reduced their involvement with IL-12 treatment research, leaving the field open to smaller biotech companies working on a variety of drug-delivery approaches that could make IL-12 safe and effective in humans.
These include injecting it directly into tumors, encasing it in various types of particles, masking the drug so it is activated only in cancer cells, and using IL-12 mRNA, which essentially turns tumor cells into IL-12–producing factories. Another IL-12 mRNA drug, from Pittsburgh-based Krystal Biotech, received a fast-track designation from the US Food and Drug Administration in February 2024 for an inhaled lung cancer treatment that packages mRNA for IL-12 and IL-2 inside an engineered virus.
And of course, there is Dr. Cheng’s inhalable treatment, culminating decades of work across three burgeoning fields.
A version of this article appeared on Medscape.com.
Cells in the human body chat with each other all the time. One major way they communicate is by releasing tiny spheres called exosomes. These carry fats, proteins, and genetic material that help regulate everything from pregnancy and immune responses to heart health and kidney function.
“Exosomes work like text messages between cells , sending and receiving information,” said lead researcher Ke Cheng, PhD, professor of biomedical engineering at Columbia. “The significance of this study is that exosomes can bring mRNA-based treatment to lung cancer cells locally, unlike systemic chemotherapy that can have side effects throughout the body. And inhalation is totally noninvasive. You don’t need a nurse to use an IV needle to pierce your skin.”
Dr. Cheng expects a human trial could launch within 5 years. For now, his study is attracting attention because it marks an advance in three areas of intense interest by researchers and biotech companies alike: Therapeutic uses of exosomes, inhalable treatments for lung conditions, and the safe delivery of powerful interleukin-12 (IL-12) immunotherapy.
Inside the Study
Dr. Cheng, who has been developing exosome and stem cell therapies for more than 15 years, and his lab team focused on lung cancer because the disease, often detected in later stages, “has a huge mortality rate,” he said. “Therapies have been suboptimal and leave the organ so damaged.”
He wanted to explore new alternatives to systemic treatments. Most are given intravenously, but Dr. Cheng thinks exosomes — also called extracellular vesicles (EVs) — could change that.
“One of the advantages of exosomes is that they are naturally secreted by the body or cultured cells,” he noted. “They have low toxicity and have multiple ways of getting their message into cells.”
The scientists borrowed an approach that captured public attention during the pandemic: Using messenger RNA, which directs cells to make proteins for tasks — including boosting immune response.
IL-12 has shown promise against cancer for decades, but early human trials triggered serious side effects and several deaths. Researchers are now trying new delivery methods that target tumor cells without affecting healthy tissue. Dr. Cheng’s team took a new approach, inserting mRNA for IL-12 into exosomes.
One aim of the study was to compare the effectiveness of inhaled exosomes vs inhaled liposomes, engineered fat droplets also under investigation as drug carriers. The team’s question: Which would work better at introducing IL-12 to the lungs to affect cancer, without triggering side effects?
After lab mice inhaled the particles through the nose, the researchers found that exosomes delivered more mRNA into cancer cells in the lungs and fought lung cancer with few side effects. Three days after treatment, researchers saw an influx of cancer-fighting T cells within tumors — with higher levels for exosome-based treatment. Plus, the exosomes led to more cancer-destroying nature killer cells and more monocytes, a sign of immune-system activation.
Researchers also found the treatment acted as a vaccine, training the immune system to battle newly introduced cancers. Little of the exosome-delivered drug escaped into the bloodstream, and the study found minimal side effects. Inhalation didn’t affect normal breathing, Dr. Cheng added.
The study’s use of inhaled exosomes makes it significant, said Raghu Kalluri, MD, PhD, professor and chair of the Department of Cancer Biology at MD Anderson Cancer Center. “This is an interesting study that explores the inhalable delivery of engineered EVs for the treatment of lung cancer and offers insights into focused delivery of EV-based drugs…with implications for diseases beyond cancer,” he said. Dr. Kalluri is also an exosome researcher.
New Frontiers
Once seen as a “quirky biological phenomenon” or just cellular trash, exosomes are now the subject of intense medical research for their potential as drug carriers, as treatments in their own right for everything from wound healing and pneumonia to heart attacks and bowel disorders, and as measurable biological markers that could lead to new tests for cancer and other conditions. One exosome-based prostate cancer test, the ExoDx Prostate Test, is already on the market.
The explosion in exosome research — the number of published studies has grown from just a handful in the early 1980s to more than 9000 — spotlights a particular focus on cancer. According to a 2021 paper in Annals of Oncology, clinical trials for exosomes in cancer treatments and tests far out-paces those for diabetes, heart disease, or neurologic conditions. Currently, 52 clinical trials using exosomes in cancer diagnosis or treatment have been completed, are underway, or are looking for participants, according to clinicaltrials.gov.
Dr. Cheng’s approach could also be used to deliver other drugs to the lungs and other organs via inhalation. “We’re testing inhalation for a different type of lung disease, acute lung injury,” Dr. Cheng said. Other potential targets include lung disorders like pulmonary hypertension. Inhaled exosomes could potentially reach the brain via the olfactory bulb or the heart as it receives oxygenated blood from the lungs.
Breathing in Medicine
So far, inhalable cancer treatments are not available outside research studies in the United States or Europe , said Remi Rosiere, PhD, a lecturer at the Université libre de Bruxelles in Brussels, Belgium, and chief scientific officer of InhaTarget Therapeutics, a company developing its own inhaled treatments for severe respiratory diseases. “Oncologists are very interested,” he said. “If you concentrate the drug on the tumor site, you can avoid distribution to the body.”
Early research into inhalable chemotherapy began in the 1960s but was unsuccessful because breathing equipment dispersed toxic cancer drugs into the air or delivered only small amounts to the lungs, he said.
New delivery techniques aim to change that. Dr. Rosiere’s company is starting a human trial of a dry powder inhaler with the chemotherapy drug cisplatin for lung cancer. Also in the pipeline is an immunotherapy treatment for lung cancer inserted in lipid nanoparticles, which are tiny fat particles similar to liposomes.
He said Dr. Cheng’s study shows the advantages of sending in exosomes. “The data are very persuasive,” Dr. Rosier said of the study. “Exosomes have a good safety profile and are able to remain in the lung for quite a long time. This prolongs exposure to the drug for greater effectiveness, without causing toxicities.”
Getting from a mouse study to a human trial will take time. “You need to understand this is very early stage,” Dr. Rosiere added. “There will be many challenges to overcome.”
One is purely practical: If the drug approaches human trials, he said, regulators will ask whether the exosomes can be produced in large quantities to meet the huge demand for new lung cancer treatments. “Lung cancer is the number one fatal cancer in the world,” Dr. Rosiere said.
A New Route for ‘Powerful’ Cancer Treatment
Meanwhile, the Columbia University study showed that inhalable exosomes are a unique delivery method for IL-12 — and could help solve a major problem that’s plagued this promising cancer treatment for decades.
Called “one of the most powerful immunotherapy agents ever discovered” in a 2022 literature review, IL-12 showed serious side effects that stalled research in the 1980s , sparking an ongoing search for new delivery methods that continues today. In 2022 and 2023, Big Pharma companies including AstraZenca, Moderna, and Bristol Myers Squib reduced their involvement with IL-12 treatment research, leaving the field open to smaller biotech companies working on a variety of drug-delivery approaches that could make IL-12 safe and effective in humans.
These include injecting it directly into tumors, encasing it in various types of particles, masking the drug so it is activated only in cancer cells, and using IL-12 mRNA, which essentially turns tumor cells into IL-12–producing factories. Another IL-12 mRNA drug, from Pittsburgh-based Krystal Biotech, received a fast-track designation from the US Food and Drug Administration in February 2024 for an inhaled lung cancer treatment that packages mRNA for IL-12 and IL-2 inside an engineered virus.
And of course, there is Dr. Cheng’s inhalable treatment, culminating decades of work across three burgeoning fields.
A version of this article appeared on Medscape.com.
FROM NATURE NANOTECHNOLOGY
Diet and Exercise in a Pill Are Real: How Mimetics Work
If couch-potato lab mice had beach-body dreams and if they could speak, they might tell you they’re thrilled by advances in the science of exercise and calorie-restriction (CR) mimetics.
In recent studies conducted at research centers across the United States, mice have chowed down, fattened up, exercised only if they felt like it, and still managed to lose body fat, improve their blood lipids, increase muscle power, avoid blood sugar problems, and boost heart function.
How did these mice get so lucky? They were given mimetics, experimental drugs that “mimic” the effects of exercise and calorie reduction in the body without the need to break a sweat or eat less.
“The mice looked like they’d done endurance training,” said Thomas Burris, PhD, chair of the Department of Pharmacodynamics at the University of Florida, Gainesville, Florida, and coauthor of a September 2023 study of the exercise mimetic SLU-PP-332, published in The Journal of Pharmacology and Experimental Therapeutics.
Meanwhile, the CR mimetic mannoheptulose (MH) “was incredibly effective at stopping the negative effects of a high-fat diet in mice,” said Donald K. Ingram, PhD, an adjunct professor at Louisiana State University’s Pennington Biomedical Research Center, Baton Rouge, Louisiana, who began studying CR mimetics at the National Institute on Aging in the 1980s. In a 2022 study published in Nutrients, MH also increased insulin sensitivity.
These “have your cake and eat it, too” drugs aren’t on the market for human use — but they’re edging closer. Several have moved into human trials with encouraging results. The National Institutes of Health and the pharmaceutical industry are taking notice, anteing up big research dollars. At the earliest, one could win US Food and Drug Administration (FDA) approval in 4-5 years, Dr. Burris said.
The medical appeal is clear: Mimetics could one day prevent and treat serious conditions such as age- and disease-related muscle loss, diabetes, heart failure, and even neurodegenerative disorders like Parkinson’s disease and Alzheimer’s disease, said the scientists studying them.
The commercial appeal is unavoidable: Mimetics have the potential to help nondieters avoid weight gain and allow dieters to build and/or preserve more calorie-burning muscle — a boon because losing weight can reduce muscle, especially with rapid loss.
How do these drugs work? What’s their downside? Like the “miracle” glucagon-like peptide 1 (GLP-1) weight-loss drugs that are now ubiquitous, are mimetics an effective pharmaceutical way to replicate two of society’s biggest lifestyle sticking points — diet and exercise?
It’s possible…
CR Mimetics: The Healthspan Drug?
From nematodes and fruit flies to yeast, Labrador Retrievers, and people, plenty of research shows that reducing calorie intake may improve health and prolong life. By how much? Cutting calories by 25% for 2 years slowed the pace of aging 2%-3% in the landmark CALERIE study of 197 adults, according to a 2023 study in Nature Aging. Sounds small, but the researchers said that equals a 10%-15% lower risk for an early death — on par with the longevity bonus you’d get from quitting smoking.
Trouble is low-cal living isn’t easy. “Diets work,” said George Roth, PhD, of GeroScience, Inc., in Pylesville, MD, who began studying CR at the National Institute on Aging in the 1980s with Ingram. “But it’s hard to sustain.”
That’s where CR mimetics come in. They activate the same health-promoting genes switched on by dieting, fasting, and extended periods of hunger, Dr. Roth said. The end result isn’t big weight loss. Instead, CR mimetics may keep us healthier and younger as we age. “Calorie restriction shifts metabolic processes in the body to protect against damage and stress,” he said.
Dr. Roth and Dr. Ingram are currently focused on the CR mimetic mannoheptulose (MH), a sugar found in unripe avocados. “It works at the first step in carbohydrate metabolism in cells throughout the body, so less energy goes through that pathway,” he said. “Glucose metabolism is reduced by 10%-15%. It’s the closest thing to actually eating less food.”
Their 2022 study found that while mice on an all-you-can-eat high-fat diet gained weight and body fat and saw blood lipids increase while insulin sensitivity decreased, mice that also got MH avoided these problems. A 2023 human study in Nutrients coauthored by Dr. Roth and Dr. Ingram found that a group consuming freeze-dried avocado had lower insulin levels than a placebo group.
Other researchers are looking at ways to stimulate the CR target nicotinamide adenine dinucleotide (NAD+). NAD+ assists sirtuins — a group of seven enzymes central to the beneficial effects of CR on aging — but levels drop with age. University of Colorado researchers are studying the effects of nicotinamide riboside (NR), an NAD+ precursor, in older adults with a $2.5 million National Institute on Aging grant. Small, preliminary human studies have found the compound reduced indicators of insulin resistance in the brain, in a January 2023 study in Aging Cell, and reduced blood pressure and arterial stiffness in a 2018 study published in Nature Communications.
Another NAD+ precursor, nicotinamide mononucleotide, reduced low-density lipoprotein cholesterol, diastolic blood pressure, and body weight in a Harvard Medical School study of 30 midlife and older adults with overweight and obesity, published in August 2023 in The Journal of Clinical Endocrinology & Metabolism. And in an April 2022 study published in Hepatology of people with nonalcoholic fatty liver disease, a proprietary supplement that included NR didn’t reduce liver fat but had a significant (vs placebo) reduction in ceramide and the liver enzyme alanine aminotransferase, a marker of inflammation.
“I think it was a pretty interesting result,” said lead researcher Leonard Guarente, PhD, professor of biology at Massachusetts Institute of Technology and founder of the supplement company Elysium. “Fatty liver progressively damages the liver. This has the potential to slow that down.”
Exercise Mimetics: Fitness in a Pill?
Physical activity builds muscle and fitness, helps keeps bones strong, sharpens thinking and memory, guards against depression, and helps discourage a slew of health concerns from weight gain and high blood pressure to diabetes and heart disease. Muscle becomes more dense, more powerful and may even burn more calories, said Dr. Burris. The problem: That pesky part about actually moving. Fewer than half of American adults get recommended amounts of aerobic exercise and fewer than a quarter fit in strength training, according to the Centers for Disease Control and Prevention.
Enter the exercise mimetics. Unlike CR mimetics, exercise mimetics affect mitochondria — the tiny power plants in muscle and every other cell in the body. They switch on genes that encourage the growth of more mitochondria and encourage them to burn fatty acids, not just glucose, for fuel.
In mice, this can keep them from gaining weight, increase insulin sensitivity, and boost exercise endurance. “We can use a drug to activate the same networks that are activated by physical activity,” said Ronald Evans, PhD, professor and director of the Gene Expression Laboratory at the Salk Institute for Biological Studies in La Jolla, California.
Among notable mimetics moving into human studies is ASP0367, a drug in a class called PPAR delta modulators first developed in Evans’ lab. ASP0367 was licensed to the pharmaceutical company Mitobridge, later acquired by Astellas. Astellas is currently running a phase 2/3 human trial of the investigational drug in people with the rare genetic disorder primary mitochondrial myopathy.
At the University of Florida, Dr. Burris and team hope to soon move the exercise mimetic SLU-PP-332 into human studies. “It targets a receptor called ERR that I’ve been working on since the 1980s,” Dr. Burris said. “We knew from genetic studies that ERR has a role in exercise’s effects on mitochondrial function in muscle.” The calorie mimetics he’s studying also activate genes for making more mitochondria and driving them to burn fatty acids. “This generates a lot of energy,” he said. In a January 2024 study in Circulation, Dr. Burris found the drug restores heart function in mice experiencing heart failure. “Very little heart function was lost,” he said. It’s had no serious side effects.
The Future of Exercise and CR Pills
The field has hit some bumps. Some feel inevitable — such as otherwise healthy people misusing the drugs. GW1516, an early experimental exercise mimetic studied by Dr. Evans and abandoned because it triggered tumor growth in lab studies, is used illegally by elite athletes as a performance-enhancing drug despite warnings from the US Anti-Doping Agency. Dr. Burris worries that future CR mimetics could be misused the same way.
But he and others see plenty of benefits in future, FDA-approved drugs. Exercise mimetics like SLU-PP-332 might one day be given to people alongside weight-loss drugs, such as Mounjaro (tirzepatide) or Ozempic (semaglutide) to prevent muscle loss. “SLU-PP-332 doesn’t affect hunger or food intake the way those drugs do,” he said. “It changes muscle.”
Mimetics may one day help older adults and people with muscle disorders rebuild muscle even when they cannot exercise and to delay a range of age-related diseases without onerous dieting. “The chance to intervene and provide a longer healthspan and lifespan — that’s been the moon shot,” Dr. Roth said.
Dr. Guarente noted that CR mimetics may work best for people who aren’t carrying extra pounds but want the health benefits of slashing calories without sacrificing meals and snacks. “Fat is still going to be a problem for joints, cholesterol, inflammation,” he said. “Calorie mimetics are not a panacea for obesity but could help preserve overall health and vitality.”
And what about the billion-dollar question: What happens when these drugs become available to a general public that has issues with actual exercise and healthy diet?
Evans sees only positives. “Our environment is designed to keep people sitting down and consuming high-calorie foods,” he said. “In the absence of people getting motivated to exercise — and there’s no evidence the country is moving in that direction on its own — a pill is an important option to have.”
A version of this article appeared on Medscape.com.
If couch-potato lab mice had beach-body dreams and if they could speak, they might tell you they’re thrilled by advances in the science of exercise and calorie-restriction (CR) mimetics.
In recent studies conducted at research centers across the United States, mice have chowed down, fattened up, exercised only if they felt like it, and still managed to lose body fat, improve their blood lipids, increase muscle power, avoid blood sugar problems, and boost heart function.
How did these mice get so lucky? They were given mimetics, experimental drugs that “mimic” the effects of exercise and calorie reduction in the body without the need to break a sweat or eat less.
“The mice looked like they’d done endurance training,” said Thomas Burris, PhD, chair of the Department of Pharmacodynamics at the University of Florida, Gainesville, Florida, and coauthor of a September 2023 study of the exercise mimetic SLU-PP-332, published in The Journal of Pharmacology and Experimental Therapeutics.
Meanwhile, the CR mimetic mannoheptulose (MH) “was incredibly effective at stopping the negative effects of a high-fat diet in mice,” said Donald K. Ingram, PhD, an adjunct professor at Louisiana State University’s Pennington Biomedical Research Center, Baton Rouge, Louisiana, who began studying CR mimetics at the National Institute on Aging in the 1980s. In a 2022 study published in Nutrients, MH also increased insulin sensitivity.
These “have your cake and eat it, too” drugs aren’t on the market for human use — but they’re edging closer. Several have moved into human trials with encouraging results. The National Institutes of Health and the pharmaceutical industry are taking notice, anteing up big research dollars. At the earliest, one could win US Food and Drug Administration (FDA) approval in 4-5 years, Dr. Burris said.
The medical appeal is clear: Mimetics could one day prevent and treat serious conditions such as age- and disease-related muscle loss, diabetes, heart failure, and even neurodegenerative disorders like Parkinson’s disease and Alzheimer’s disease, said the scientists studying them.
The commercial appeal is unavoidable: Mimetics have the potential to help nondieters avoid weight gain and allow dieters to build and/or preserve more calorie-burning muscle — a boon because losing weight can reduce muscle, especially with rapid loss.
How do these drugs work? What’s their downside? Like the “miracle” glucagon-like peptide 1 (GLP-1) weight-loss drugs that are now ubiquitous, are mimetics an effective pharmaceutical way to replicate two of society’s biggest lifestyle sticking points — diet and exercise?
It’s possible…
CR Mimetics: The Healthspan Drug?
From nematodes and fruit flies to yeast, Labrador Retrievers, and people, plenty of research shows that reducing calorie intake may improve health and prolong life. By how much? Cutting calories by 25% for 2 years slowed the pace of aging 2%-3% in the landmark CALERIE study of 197 adults, according to a 2023 study in Nature Aging. Sounds small, but the researchers said that equals a 10%-15% lower risk for an early death — on par with the longevity bonus you’d get from quitting smoking.
Trouble is low-cal living isn’t easy. “Diets work,” said George Roth, PhD, of GeroScience, Inc., in Pylesville, MD, who began studying CR at the National Institute on Aging in the 1980s with Ingram. “But it’s hard to sustain.”
That’s where CR mimetics come in. They activate the same health-promoting genes switched on by dieting, fasting, and extended periods of hunger, Dr. Roth said. The end result isn’t big weight loss. Instead, CR mimetics may keep us healthier and younger as we age. “Calorie restriction shifts metabolic processes in the body to protect against damage and stress,” he said.
Dr. Roth and Dr. Ingram are currently focused on the CR mimetic mannoheptulose (MH), a sugar found in unripe avocados. “It works at the first step in carbohydrate metabolism in cells throughout the body, so less energy goes through that pathway,” he said. “Glucose metabolism is reduced by 10%-15%. It’s the closest thing to actually eating less food.”
Their 2022 study found that while mice on an all-you-can-eat high-fat diet gained weight and body fat and saw blood lipids increase while insulin sensitivity decreased, mice that also got MH avoided these problems. A 2023 human study in Nutrients coauthored by Dr. Roth and Dr. Ingram found that a group consuming freeze-dried avocado had lower insulin levels than a placebo group.
Other researchers are looking at ways to stimulate the CR target nicotinamide adenine dinucleotide (NAD+). NAD+ assists sirtuins — a group of seven enzymes central to the beneficial effects of CR on aging — but levels drop with age. University of Colorado researchers are studying the effects of nicotinamide riboside (NR), an NAD+ precursor, in older adults with a $2.5 million National Institute on Aging grant. Small, preliminary human studies have found the compound reduced indicators of insulin resistance in the brain, in a January 2023 study in Aging Cell, and reduced blood pressure and arterial stiffness in a 2018 study published in Nature Communications.
Another NAD+ precursor, nicotinamide mononucleotide, reduced low-density lipoprotein cholesterol, diastolic blood pressure, and body weight in a Harvard Medical School study of 30 midlife and older adults with overweight and obesity, published in August 2023 in The Journal of Clinical Endocrinology & Metabolism. And in an April 2022 study published in Hepatology of people with nonalcoholic fatty liver disease, a proprietary supplement that included NR didn’t reduce liver fat but had a significant (vs placebo) reduction in ceramide and the liver enzyme alanine aminotransferase, a marker of inflammation.
“I think it was a pretty interesting result,” said lead researcher Leonard Guarente, PhD, professor of biology at Massachusetts Institute of Technology and founder of the supplement company Elysium. “Fatty liver progressively damages the liver. This has the potential to slow that down.”
Exercise Mimetics: Fitness in a Pill?
Physical activity builds muscle and fitness, helps keeps bones strong, sharpens thinking and memory, guards against depression, and helps discourage a slew of health concerns from weight gain and high blood pressure to diabetes and heart disease. Muscle becomes more dense, more powerful and may even burn more calories, said Dr. Burris. The problem: That pesky part about actually moving. Fewer than half of American adults get recommended amounts of aerobic exercise and fewer than a quarter fit in strength training, according to the Centers for Disease Control and Prevention.
Enter the exercise mimetics. Unlike CR mimetics, exercise mimetics affect mitochondria — the tiny power plants in muscle and every other cell in the body. They switch on genes that encourage the growth of more mitochondria and encourage them to burn fatty acids, not just glucose, for fuel.
In mice, this can keep them from gaining weight, increase insulin sensitivity, and boost exercise endurance. “We can use a drug to activate the same networks that are activated by physical activity,” said Ronald Evans, PhD, professor and director of the Gene Expression Laboratory at the Salk Institute for Biological Studies in La Jolla, California.
Among notable mimetics moving into human studies is ASP0367, a drug in a class called PPAR delta modulators first developed in Evans’ lab. ASP0367 was licensed to the pharmaceutical company Mitobridge, later acquired by Astellas. Astellas is currently running a phase 2/3 human trial of the investigational drug in people with the rare genetic disorder primary mitochondrial myopathy.
At the University of Florida, Dr. Burris and team hope to soon move the exercise mimetic SLU-PP-332 into human studies. “It targets a receptor called ERR that I’ve been working on since the 1980s,” Dr. Burris said. “We knew from genetic studies that ERR has a role in exercise’s effects on mitochondrial function in muscle.” The calorie mimetics he’s studying also activate genes for making more mitochondria and driving them to burn fatty acids. “This generates a lot of energy,” he said. In a January 2024 study in Circulation, Dr. Burris found the drug restores heart function in mice experiencing heart failure. “Very little heart function was lost,” he said. It’s had no serious side effects.
The Future of Exercise and CR Pills
The field has hit some bumps. Some feel inevitable — such as otherwise healthy people misusing the drugs. GW1516, an early experimental exercise mimetic studied by Dr. Evans and abandoned because it triggered tumor growth in lab studies, is used illegally by elite athletes as a performance-enhancing drug despite warnings from the US Anti-Doping Agency. Dr. Burris worries that future CR mimetics could be misused the same way.
But he and others see plenty of benefits in future, FDA-approved drugs. Exercise mimetics like SLU-PP-332 might one day be given to people alongside weight-loss drugs, such as Mounjaro (tirzepatide) or Ozempic (semaglutide) to prevent muscle loss. “SLU-PP-332 doesn’t affect hunger or food intake the way those drugs do,” he said. “It changes muscle.”
Mimetics may one day help older adults and people with muscle disorders rebuild muscle even when they cannot exercise and to delay a range of age-related diseases without onerous dieting. “The chance to intervene and provide a longer healthspan and lifespan — that’s been the moon shot,” Dr. Roth said.
Dr. Guarente noted that CR mimetics may work best for people who aren’t carrying extra pounds but want the health benefits of slashing calories without sacrificing meals and snacks. “Fat is still going to be a problem for joints, cholesterol, inflammation,” he said. “Calorie mimetics are not a panacea for obesity but could help preserve overall health and vitality.”
And what about the billion-dollar question: What happens when these drugs become available to a general public that has issues with actual exercise and healthy diet?
Evans sees only positives. “Our environment is designed to keep people sitting down and consuming high-calorie foods,” he said. “In the absence of people getting motivated to exercise — and there’s no evidence the country is moving in that direction on its own — a pill is an important option to have.”
A version of this article appeared on Medscape.com.
If couch-potato lab mice had beach-body dreams and if they could speak, they might tell you they’re thrilled by advances in the science of exercise and calorie-restriction (CR) mimetics.
In recent studies conducted at research centers across the United States, mice have chowed down, fattened up, exercised only if they felt like it, and still managed to lose body fat, improve their blood lipids, increase muscle power, avoid blood sugar problems, and boost heart function.
How did these mice get so lucky? They were given mimetics, experimental drugs that “mimic” the effects of exercise and calorie reduction in the body without the need to break a sweat or eat less.
“The mice looked like they’d done endurance training,” said Thomas Burris, PhD, chair of the Department of Pharmacodynamics at the University of Florida, Gainesville, Florida, and coauthor of a September 2023 study of the exercise mimetic SLU-PP-332, published in The Journal of Pharmacology and Experimental Therapeutics.
Meanwhile, the CR mimetic mannoheptulose (MH) “was incredibly effective at stopping the negative effects of a high-fat diet in mice,” said Donald K. Ingram, PhD, an adjunct professor at Louisiana State University’s Pennington Biomedical Research Center, Baton Rouge, Louisiana, who began studying CR mimetics at the National Institute on Aging in the 1980s. In a 2022 study published in Nutrients, MH also increased insulin sensitivity.
These “have your cake and eat it, too” drugs aren’t on the market for human use — but they’re edging closer. Several have moved into human trials with encouraging results. The National Institutes of Health and the pharmaceutical industry are taking notice, anteing up big research dollars. At the earliest, one could win US Food and Drug Administration (FDA) approval in 4-5 years, Dr. Burris said.
The medical appeal is clear: Mimetics could one day prevent and treat serious conditions such as age- and disease-related muscle loss, diabetes, heart failure, and even neurodegenerative disorders like Parkinson’s disease and Alzheimer’s disease, said the scientists studying them.
The commercial appeal is unavoidable: Mimetics have the potential to help nondieters avoid weight gain and allow dieters to build and/or preserve more calorie-burning muscle — a boon because losing weight can reduce muscle, especially with rapid loss.
How do these drugs work? What’s their downside? Like the “miracle” glucagon-like peptide 1 (GLP-1) weight-loss drugs that are now ubiquitous, are mimetics an effective pharmaceutical way to replicate two of society’s biggest lifestyle sticking points — diet and exercise?
It’s possible…
CR Mimetics: The Healthspan Drug?
From nematodes and fruit flies to yeast, Labrador Retrievers, and people, plenty of research shows that reducing calorie intake may improve health and prolong life. By how much? Cutting calories by 25% for 2 years slowed the pace of aging 2%-3% in the landmark CALERIE study of 197 adults, according to a 2023 study in Nature Aging. Sounds small, but the researchers said that equals a 10%-15% lower risk for an early death — on par with the longevity bonus you’d get from quitting smoking.
Trouble is low-cal living isn’t easy. “Diets work,” said George Roth, PhD, of GeroScience, Inc., in Pylesville, MD, who began studying CR at the National Institute on Aging in the 1980s with Ingram. “But it’s hard to sustain.”
That’s where CR mimetics come in. They activate the same health-promoting genes switched on by dieting, fasting, and extended periods of hunger, Dr. Roth said. The end result isn’t big weight loss. Instead, CR mimetics may keep us healthier and younger as we age. “Calorie restriction shifts metabolic processes in the body to protect against damage and stress,” he said.
Dr. Roth and Dr. Ingram are currently focused on the CR mimetic mannoheptulose (MH), a sugar found in unripe avocados. “It works at the first step in carbohydrate metabolism in cells throughout the body, so less energy goes through that pathway,” he said. “Glucose metabolism is reduced by 10%-15%. It’s the closest thing to actually eating less food.”
Their 2022 study found that while mice on an all-you-can-eat high-fat diet gained weight and body fat and saw blood lipids increase while insulin sensitivity decreased, mice that also got MH avoided these problems. A 2023 human study in Nutrients coauthored by Dr. Roth and Dr. Ingram found that a group consuming freeze-dried avocado had lower insulin levels than a placebo group.
Other researchers are looking at ways to stimulate the CR target nicotinamide adenine dinucleotide (NAD+). NAD+ assists sirtuins — a group of seven enzymes central to the beneficial effects of CR on aging — but levels drop with age. University of Colorado researchers are studying the effects of nicotinamide riboside (NR), an NAD+ precursor, in older adults with a $2.5 million National Institute on Aging grant. Small, preliminary human studies have found the compound reduced indicators of insulin resistance in the brain, in a January 2023 study in Aging Cell, and reduced blood pressure and arterial stiffness in a 2018 study published in Nature Communications.
Another NAD+ precursor, nicotinamide mononucleotide, reduced low-density lipoprotein cholesterol, diastolic blood pressure, and body weight in a Harvard Medical School study of 30 midlife and older adults with overweight and obesity, published in August 2023 in The Journal of Clinical Endocrinology & Metabolism. And in an April 2022 study published in Hepatology of people with nonalcoholic fatty liver disease, a proprietary supplement that included NR didn’t reduce liver fat but had a significant (vs placebo) reduction in ceramide and the liver enzyme alanine aminotransferase, a marker of inflammation.
“I think it was a pretty interesting result,” said lead researcher Leonard Guarente, PhD, professor of biology at Massachusetts Institute of Technology and founder of the supplement company Elysium. “Fatty liver progressively damages the liver. This has the potential to slow that down.”
Exercise Mimetics: Fitness in a Pill?
Physical activity builds muscle and fitness, helps keeps bones strong, sharpens thinking and memory, guards against depression, and helps discourage a slew of health concerns from weight gain and high blood pressure to diabetes and heart disease. Muscle becomes more dense, more powerful and may even burn more calories, said Dr. Burris. The problem: That pesky part about actually moving. Fewer than half of American adults get recommended amounts of aerobic exercise and fewer than a quarter fit in strength training, according to the Centers for Disease Control and Prevention.
Enter the exercise mimetics. Unlike CR mimetics, exercise mimetics affect mitochondria — the tiny power plants in muscle and every other cell in the body. They switch on genes that encourage the growth of more mitochondria and encourage them to burn fatty acids, not just glucose, for fuel.
In mice, this can keep them from gaining weight, increase insulin sensitivity, and boost exercise endurance. “We can use a drug to activate the same networks that are activated by physical activity,” said Ronald Evans, PhD, professor and director of the Gene Expression Laboratory at the Salk Institute for Biological Studies in La Jolla, California.
Among notable mimetics moving into human studies is ASP0367, a drug in a class called PPAR delta modulators first developed in Evans’ lab. ASP0367 was licensed to the pharmaceutical company Mitobridge, later acquired by Astellas. Astellas is currently running a phase 2/3 human trial of the investigational drug in people with the rare genetic disorder primary mitochondrial myopathy.
At the University of Florida, Dr. Burris and team hope to soon move the exercise mimetic SLU-PP-332 into human studies. “It targets a receptor called ERR that I’ve been working on since the 1980s,” Dr. Burris said. “We knew from genetic studies that ERR has a role in exercise’s effects on mitochondrial function in muscle.” The calorie mimetics he’s studying also activate genes for making more mitochondria and driving them to burn fatty acids. “This generates a lot of energy,” he said. In a January 2024 study in Circulation, Dr. Burris found the drug restores heart function in mice experiencing heart failure. “Very little heart function was lost,” he said. It’s had no serious side effects.
The Future of Exercise and CR Pills
The field has hit some bumps. Some feel inevitable — such as otherwise healthy people misusing the drugs. GW1516, an early experimental exercise mimetic studied by Dr. Evans and abandoned because it triggered tumor growth in lab studies, is used illegally by elite athletes as a performance-enhancing drug despite warnings from the US Anti-Doping Agency. Dr. Burris worries that future CR mimetics could be misused the same way.
But he and others see plenty of benefits in future, FDA-approved drugs. Exercise mimetics like SLU-PP-332 might one day be given to people alongside weight-loss drugs, such as Mounjaro (tirzepatide) or Ozempic (semaglutide) to prevent muscle loss. “SLU-PP-332 doesn’t affect hunger or food intake the way those drugs do,” he said. “It changes muscle.”
Mimetics may one day help older adults and people with muscle disorders rebuild muscle even when they cannot exercise and to delay a range of age-related diseases without onerous dieting. “The chance to intervene and provide a longer healthspan and lifespan — that’s been the moon shot,” Dr. Roth said.
Dr. Guarente noted that CR mimetics may work best for people who aren’t carrying extra pounds but want the health benefits of slashing calories without sacrificing meals and snacks. “Fat is still going to be a problem for joints, cholesterol, inflammation,” he said. “Calorie mimetics are not a panacea for obesity but could help preserve overall health and vitality.”
And what about the billion-dollar question: What happens when these drugs become available to a general public that has issues with actual exercise and healthy diet?
Evans sees only positives. “Our environment is designed to keep people sitting down and consuming high-calorie foods,” he said. “In the absence of people getting motivated to exercise — and there’s no evidence the country is moving in that direction on its own — a pill is an important option to have.”
A version of this article appeared on Medscape.com.