User login
The Food and Drug Administration’s approval of leflunomide in September 1998 as a treatment for rheumatoid arthritis was sandwiched between the debuts of infliximab (Remicade and biosimilars) and etanercept (Enbrel) in August and November of that year, the latter of which was so exciting that “within 2 months you couldn’t get [it],” recalled Eric M. Ruderman, MD. And “like every middle child, [leflunomide] was underloved, underappreciated, and largely dismissed.”
Yet should it have been? Is it worth another look today?
At the 2024 Rheumatology Winter Clinical Symposium, Dr. Ruderman reflected on some of the clinical trial data published after leflunomide’s approval that “got lost in the shuffle” of the rightful embrace of biologics in United States practice, and urged reconsideration of the loading strategy still advised in the drug’s labeling.
“I’m not telling you that you should be using [leflunomide] in place of biologics, instead of biologics, or before biologics … but it should be in your toolkit,” said Dr. Ruderman, professor of medicine and associate chief of clinical affairs in the division of rheumatology at Northwestern University Feinberg School of Medicine, Chicago. The drug “still has a role in RA, including in combination with methotrexate, and a potential role in other rheumatic diseases.”
“In our PsA clinic,” he noted, “we’ve actually not infrequently added leflunomide to some of the other agents we’ve been using.”
Key Findings Over the Years in RA
Leflunomide showed efficacy similar to that of sulfasalazine in a randomized trial published in 1999 that used primary endpoints of tender/swollen joints and physician and patient global scores. Then, against methotrexate, it proved just as efficacious in achieving at least 20% improvement in American College of Rheumatology composite response criteria (ACR20) over 52 weeks, and in meeting endpoints similar to those of the sulfasalazine trial, in two trials, one published in 1999 and another in 2000.
“So here were two big trials [comparing it with methotrexate] that suggested the drug was just as good as what had become our standard of care by that point,” Dr. Ruderman said.
Each of these three trials used a loading dose of 100 mg leflunomide for 3 days, followed by 20 mg daily. Sulfasalazine was initiated at 2 g and escalated over 4 weeks. Methotrexate was initiated in one of the trials at a dose of 7.5 mg, then increased to 15 mg in almost two-thirds of patients; in the other methotrexate trial the initial dose was 15 mg escalated over 3 months.
Side effects of leflunomide — GI issues, rash, alopecia (reversible), and elevated liver function tests — were similar across the trials, and represented “about the same toxicities as methotrexate,” he said.
Researchers then tested leflunomide as an add-on to methotrexate in patients who had inadequate response, which “was a little bit daunting since we were still concerned about the toxicity of methotrexate at this point,” Dr. Ruderman said. “The idea that we’d take another drug with similar toxicities and add it on to the methotrexate was a little scary.”
But it worked. Patients on a mean background dose of 16.5 mg methotrexate were randomized to placebo or to a 2-day leflunomide loading dose followed by 10 mg/day that could be escalated at 8 weeks to 20 mg if needed. At 6 months, 19.5% and 46.2%, respectively, met ACR20 (P < .001), and “interestingly,” he said, “adverse events were pretty similar” between combination therapy and methotrexate monotherapy.
“This was very much like all the studies we’ve seen over the years with new biologics — they were all added to background methotrexate,” he said. “And the truth is, the [46%] response seen when adding leflunomide to background methotrexate wasn’t very different from the 50% [ACR20] response you tend to see when you add a biologic.”
However, despite the study’s conclusion that combination therapy provided significant benefit to patients with inadequate response to methotrexate alone, “the drug got lost, because everyone was prescribing the biologics,” Dr. Ruderman said.
He said he found only one study comparing leflunomide with a biologic. In a notably small but well-designed study from Sri Lanka published in 2017, 40 patients with an inadequate response to methotrexate were randomized to low-dose rituximab (500 mg x 2) or 20 mg/day leflunomide (no loading dose). At week 24, ACR20 was nearly identical (85% vs 84%), with a similar rate of adverse events.
The researchers pointed out “that there’s a potential cost benefit in developing countries where biologics aren’t as accessible,” he said, agreeing that “the big opportunity for a drug like leflunomide is outside the US, where you don’t have access to the drugs we take advantage of all the time.”
A meeting participant from Canada pointed out that rheumatologists there are “mandated to use it for PsA in combination with methotrexate before we can get a biologic, and for RA we can use it with Plaquenil [hydroxychloroquine] and methotrexate before we get a biologic, so we’re using it all the time.”
Asked about efficacy, the physician said the combination with methotrexate is “absolutely” efficacious. “It works really well” he said. “The problem is, you really have to watch the white cell count and liver function … and the half-life is long.”
Indeed, Dr. Ruderman said during his talk, the plasma half-life of teriflunomide, its active metabolite, is 15.5 days, which is challenging when adverse events occur. “And it’s a terrible drug in young women thinking about pregnancy because it’s teratogenic and stays around,” he said.
Leflunomide, which, notably, was “developed specifically for RA from the get-go” and not borrowed from another specialty, works by blocking de novo pyrimidine synthesis, Dr. Ruderman said. T-cell activation requires the upregulation of pyrimidine production (salvage pathways are insufficient); the “drug prevents that” by inhibiting an enzyme that catalyzes conversion of dihydroorotate to orotate, which, in turn, is converted to pyrimidine ribonucleotides, he explained.
Other potential mechanisms of action have been proposed — mainly, inhibition of tumor necrosis factor signaling and inhibition of kinase activity, including the JAK/STAT pathway — but “there’s not great data for any of them,” he said.
Loading vs Not Loading, and Its Role in PsA and Other Diseases
“We stopped loading years ago because at 100 mg for 3 days in a row, everyone has GI issues,” Dr. Ruderman said. “It may have made sense from a pharmacokinetic standpoint because [based on the long half-life] you could get to a higher drug level quicker, but not a practical standpoint, because patients would stop the drug — they couldn’t take it.” The first study to examine the necessity of loading leflunomide in a “prospective, careful way” was published in 2013. It randomized 120 patients to 100 mg or 20 mg for 3 days, followed by a 3-month open-label period of 20 mg, and found no clinical benefit with loading but more diarrhea and elevated liver enzymes.
“It tells us something about how we need to think about half-lives,” he said. “Maybe [loading is] not necessary because the biological effects are different than the drug levels.”
In the PsA space, in 2004, researchers reported a double-blind randomized trial in which 190 patients with active PsA and cutaneous psoriasis with at least 3% body surface area involvement were randomized to receive leflunomide (a loading dose followed by 20 mg/day) or placebo for 24 weeks. Almost 60% of leflunomide-treated patients, compared with 30% of placebo-treated patients, were classified as responders by the Psoriatic Arthritis Response criteria (P < .0001), “which is a soft endpoint” but was utilized at the time, Dr. Ruderman said. The researchers noted improvements in ACR20 and skin responses as well, and toxicity was similar to that reported in the RA studies.
However, approval was never sought, and the drug was infrequently prescribed, “because etanercept came out for this disease, and then adalimumab … and then the world changed,” he said.
More recently, a single-center, double-blind, randomized trial that included 78 Dutch patients with PsA tested leflunomide plus methotrexate vs methotrexate monotherapy and was published in The Lancet Rheumatology. After 16 weeks, mean Psoriatic Arthritis Disease Activity Score (PASDAS) had improved for patients in the combination therapy group in comparison with the monotherapy group (3.1 [standard deviation (SD), 1.4] vs 3.7 [SD, 1.3]; treatment difference, -0.6; 90% CI, -1.0 to -0.1; P = .025). The combination therapy group also achieved PASDAS low disease activity at a higher rate (59%) than that of the monotherapy group (34%; P = .019). Three patients in the combination therapy group experienced serious adverse events, two of which were deemed unrelated to leflunomide. The most frequently occurring adverse events were nausea or vomiting, tiredness, and elevated alanine aminotransferase. Mild adverse events were more common in the methotrexate plus leflunomide group.
In an interview after the meeting, Dr. Ruderman explained that in his practice, about 15 years ago, leflunomide was sometimes prescribed as an alternative to a biologic change for patients whose skin disease improved significantly with ustekinumab (Stelara) but who “suddenly had more joint symptoms that they didn’t have before.”
And “we’ve found ourselves a bit recently with the same sort of story, where patients are prescribed IL-23 inhibitors like Skyrizi [risankizumab] and Tremfya [guselkumab] and their skin does really well but now they’re having more joint symptoms than previously,” he said. “Our choices are to switch to a whole different biologic, or to think about adding something as an adjunct — and maybe leflunomide is a reasonable option.”
In the last 5 years, Dr. Ruderman noted, randomized trial data has been published on leflunomide in lupus nephritis induction, and in lupus nephritis maintenance, as well as in IgG4-related disease.
Dr. Ruderman disclosed consulting and/or drug safety monitoring board work for AbbVie, Amgen, Bristol-Myers Squibb, Janssen, Lilly, Merck, Novartis, NS Pharma, and UCB.
The Food and Drug Administration’s approval of leflunomide in September 1998 as a treatment for rheumatoid arthritis was sandwiched between the debuts of infliximab (Remicade and biosimilars) and etanercept (Enbrel) in August and November of that year, the latter of which was so exciting that “within 2 months you couldn’t get [it],” recalled Eric M. Ruderman, MD. And “like every middle child, [leflunomide] was underloved, underappreciated, and largely dismissed.”
Yet should it have been? Is it worth another look today?
At the 2024 Rheumatology Winter Clinical Symposium, Dr. Ruderman reflected on some of the clinical trial data published after leflunomide’s approval that “got lost in the shuffle” of the rightful embrace of biologics in United States practice, and urged reconsideration of the loading strategy still advised in the drug’s labeling.
“I’m not telling you that you should be using [leflunomide] in place of biologics, instead of biologics, or before biologics … but it should be in your toolkit,” said Dr. Ruderman, professor of medicine and associate chief of clinical affairs in the division of rheumatology at Northwestern University Feinberg School of Medicine, Chicago. The drug “still has a role in RA, including in combination with methotrexate, and a potential role in other rheumatic diseases.”
“In our PsA clinic,” he noted, “we’ve actually not infrequently added leflunomide to some of the other agents we’ve been using.”
Key Findings Over the Years in RA
Leflunomide showed efficacy similar to that of sulfasalazine in a randomized trial published in 1999 that used primary endpoints of tender/swollen joints and physician and patient global scores. Then, against methotrexate, it proved just as efficacious in achieving at least 20% improvement in American College of Rheumatology composite response criteria (ACR20) over 52 weeks, and in meeting endpoints similar to those of the sulfasalazine trial, in two trials, one published in 1999 and another in 2000.
“So here were two big trials [comparing it with methotrexate] that suggested the drug was just as good as what had become our standard of care by that point,” Dr. Ruderman said.
Each of these three trials used a loading dose of 100 mg leflunomide for 3 days, followed by 20 mg daily. Sulfasalazine was initiated at 2 g and escalated over 4 weeks. Methotrexate was initiated in one of the trials at a dose of 7.5 mg, then increased to 15 mg in almost two-thirds of patients; in the other methotrexate trial the initial dose was 15 mg escalated over 3 months.
Side effects of leflunomide — GI issues, rash, alopecia (reversible), and elevated liver function tests — were similar across the trials, and represented “about the same toxicities as methotrexate,” he said.
Researchers then tested leflunomide as an add-on to methotrexate in patients who had inadequate response, which “was a little bit daunting since we were still concerned about the toxicity of methotrexate at this point,” Dr. Ruderman said. “The idea that we’d take another drug with similar toxicities and add it on to the methotrexate was a little scary.”
But it worked. Patients on a mean background dose of 16.5 mg methotrexate were randomized to placebo or to a 2-day leflunomide loading dose followed by 10 mg/day that could be escalated at 8 weeks to 20 mg if needed. At 6 months, 19.5% and 46.2%, respectively, met ACR20 (P < .001), and “interestingly,” he said, “adverse events were pretty similar” between combination therapy and methotrexate monotherapy.
“This was very much like all the studies we’ve seen over the years with new biologics — they were all added to background methotrexate,” he said. “And the truth is, the [46%] response seen when adding leflunomide to background methotrexate wasn’t very different from the 50% [ACR20] response you tend to see when you add a biologic.”
However, despite the study’s conclusion that combination therapy provided significant benefit to patients with inadequate response to methotrexate alone, “the drug got lost, because everyone was prescribing the biologics,” Dr. Ruderman said.
He said he found only one study comparing leflunomide with a biologic. In a notably small but well-designed study from Sri Lanka published in 2017, 40 patients with an inadequate response to methotrexate were randomized to low-dose rituximab (500 mg x 2) or 20 mg/day leflunomide (no loading dose). At week 24, ACR20 was nearly identical (85% vs 84%), with a similar rate of adverse events.
The researchers pointed out “that there’s a potential cost benefit in developing countries where biologics aren’t as accessible,” he said, agreeing that “the big opportunity for a drug like leflunomide is outside the US, where you don’t have access to the drugs we take advantage of all the time.”
A meeting participant from Canada pointed out that rheumatologists there are “mandated to use it for PsA in combination with methotrexate before we can get a biologic, and for RA we can use it with Plaquenil [hydroxychloroquine] and methotrexate before we get a biologic, so we’re using it all the time.”
Asked about efficacy, the physician said the combination with methotrexate is “absolutely” efficacious. “It works really well” he said. “The problem is, you really have to watch the white cell count and liver function … and the half-life is long.”
Indeed, Dr. Ruderman said during his talk, the plasma half-life of teriflunomide, its active metabolite, is 15.5 days, which is challenging when adverse events occur. “And it’s a terrible drug in young women thinking about pregnancy because it’s teratogenic and stays around,” he said.
Leflunomide, which, notably, was “developed specifically for RA from the get-go” and not borrowed from another specialty, works by blocking de novo pyrimidine synthesis, Dr. Ruderman said. T-cell activation requires the upregulation of pyrimidine production (salvage pathways are insufficient); the “drug prevents that” by inhibiting an enzyme that catalyzes conversion of dihydroorotate to orotate, which, in turn, is converted to pyrimidine ribonucleotides, he explained.
Other potential mechanisms of action have been proposed — mainly, inhibition of tumor necrosis factor signaling and inhibition of kinase activity, including the JAK/STAT pathway — but “there’s not great data for any of them,” he said.
Loading vs Not Loading, and Its Role in PsA and Other Diseases
“We stopped loading years ago because at 100 mg for 3 days in a row, everyone has GI issues,” Dr. Ruderman said. “It may have made sense from a pharmacokinetic standpoint because [based on the long half-life] you could get to a higher drug level quicker, but not a practical standpoint, because patients would stop the drug — they couldn’t take it.” The first study to examine the necessity of loading leflunomide in a “prospective, careful way” was published in 2013. It randomized 120 patients to 100 mg or 20 mg for 3 days, followed by a 3-month open-label period of 20 mg, and found no clinical benefit with loading but more diarrhea and elevated liver enzymes.
“It tells us something about how we need to think about half-lives,” he said. “Maybe [loading is] not necessary because the biological effects are different than the drug levels.”
In the PsA space, in 2004, researchers reported a double-blind randomized trial in which 190 patients with active PsA and cutaneous psoriasis with at least 3% body surface area involvement were randomized to receive leflunomide (a loading dose followed by 20 mg/day) or placebo for 24 weeks. Almost 60% of leflunomide-treated patients, compared with 30% of placebo-treated patients, were classified as responders by the Psoriatic Arthritis Response criteria (P < .0001), “which is a soft endpoint” but was utilized at the time, Dr. Ruderman said. The researchers noted improvements in ACR20 and skin responses as well, and toxicity was similar to that reported in the RA studies.
However, approval was never sought, and the drug was infrequently prescribed, “because etanercept came out for this disease, and then adalimumab … and then the world changed,” he said.
More recently, a single-center, double-blind, randomized trial that included 78 Dutch patients with PsA tested leflunomide plus methotrexate vs methotrexate monotherapy and was published in The Lancet Rheumatology. After 16 weeks, mean Psoriatic Arthritis Disease Activity Score (PASDAS) had improved for patients in the combination therapy group in comparison with the monotherapy group (3.1 [standard deviation (SD), 1.4] vs 3.7 [SD, 1.3]; treatment difference, -0.6; 90% CI, -1.0 to -0.1; P = .025). The combination therapy group also achieved PASDAS low disease activity at a higher rate (59%) than that of the monotherapy group (34%; P = .019). Three patients in the combination therapy group experienced serious adverse events, two of which were deemed unrelated to leflunomide. The most frequently occurring adverse events were nausea or vomiting, tiredness, and elevated alanine aminotransferase. Mild adverse events were more common in the methotrexate plus leflunomide group.
In an interview after the meeting, Dr. Ruderman explained that in his practice, about 15 years ago, leflunomide was sometimes prescribed as an alternative to a biologic change for patients whose skin disease improved significantly with ustekinumab (Stelara) but who “suddenly had more joint symptoms that they didn’t have before.”
And “we’ve found ourselves a bit recently with the same sort of story, where patients are prescribed IL-23 inhibitors like Skyrizi [risankizumab] and Tremfya [guselkumab] and their skin does really well but now they’re having more joint symptoms than previously,” he said. “Our choices are to switch to a whole different biologic, or to think about adding something as an adjunct — and maybe leflunomide is a reasonable option.”
In the last 5 years, Dr. Ruderman noted, randomized trial data has been published on leflunomide in lupus nephritis induction, and in lupus nephritis maintenance, as well as in IgG4-related disease.
Dr. Ruderman disclosed consulting and/or drug safety monitoring board work for AbbVie, Amgen, Bristol-Myers Squibb, Janssen, Lilly, Merck, Novartis, NS Pharma, and UCB.
The Food and Drug Administration’s approval of leflunomide in September 1998 as a treatment for rheumatoid arthritis was sandwiched between the debuts of infliximab (Remicade and biosimilars) and etanercept (Enbrel) in August and November of that year, the latter of which was so exciting that “within 2 months you couldn’t get [it],” recalled Eric M. Ruderman, MD. And “like every middle child, [leflunomide] was underloved, underappreciated, and largely dismissed.”
Yet should it have been? Is it worth another look today?
At the 2024 Rheumatology Winter Clinical Symposium, Dr. Ruderman reflected on some of the clinical trial data published after leflunomide’s approval that “got lost in the shuffle” of the rightful embrace of biologics in United States practice, and urged reconsideration of the loading strategy still advised in the drug’s labeling.
“I’m not telling you that you should be using [leflunomide] in place of biologics, instead of biologics, or before biologics … but it should be in your toolkit,” said Dr. Ruderman, professor of medicine and associate chief of clinical affairs in the division of rheumatology at Northwestern University Feinberg School of Medicine, Chicago. The drug “still has a role in RA, including in combination with methotrexate, and a potential role in other rheumatic diseases.”
“In our PsA clinic,” he noted, “we’ve actually not infrequently added leflunomide to some of the other agents we’ve been using.”
Key Findings Over the Years in RA
Leflunomide showed efficacy similar to that of sulfasalazine in a randomized trial published in 1999 that used primary endpoints of tender/swollen joints and physician and patient global scores. Then, against methotrexate, it proved just as efficacious in achieving at least 20% improvement in American College of Rheumatology composite response criteria (ACR20) over 52 weeks, and in meeting endpoints similar to those of the sulfasalazine trial, in two trials, one published in 1999 and another in 2000.
“So here were two big trials [comparing it with methotrexate] that suggested the drug was just as good as what had become our standard of care by that point,” Dr. Ruderman said.
Each of these three trials used a loading dose of 100 mg leflunomide for 3 days, followed by 20 mg daily. Sulfasalazine was initiated at 2 g and escalated over 4 weeks. Methotrexate was initiated in one of the trials at a dose of 7.5 mg, then increased to 15 mg in almost two-thirds of patients; in the other methotrexate trial the initial dose was 15 mg escalated over 3 months.
Side effects of leflunomide — GI issues, rash, alopecia (reversible), and elevated liver function tests — were similar across the trials, and represented “about the same toxicities as methotrexate,” he said.
Researchers then tested leflunomide as an add-on to methotrexate in patients who had inadequate response, which “was a little bit daunting since we were still concerned about the toxicity of methotrexate at this point,” Dr. Ruderman said. “The idea that we’d take another drug with similar toxicities and add it on to the methotrexate was a little scary.”
But it worked. Patients on a mean background dose of 16.5 mg methotrexate were randomized to placebo or to a 2-day leflunomide loading dose followed by 10 mg/day that could be escalated at 8 weeks to 20 mg if needed. At 6 months, 19.5% and 46.2%, respectively, met ACR20 (P < .001), and “interestingly,” he said, “adverse events were pretty similar” between combination therapy and methotrexate monotherapy.
“This was very much like all the studies we’ve seen over the years with new biologics — they were all added to background methotrexate,” he said. “And the truth is, the [46%] response seen when adding leflunomide to background methotrexate wasn’t very different from the 50% [ACR20] response you tend to see when you add a biologic.”
However, despite the study’s conclusion that combination therapy provided significant benefit to patients with inadequate response to methotrexate alone, “the drug got lost, because everyone was prescribing the biologics,” Dr. Ruderman said.
He said he found only one study comparing leflunomide with a biologic. In a notably small but well-designed study from Sri Lanka published in 2017, 40 patients with an inadequate response to methotrexate were randomized to low-dose rituximab (500 mg x 2) or 20 mg/day leflunomide (no loading dose). At week 24, ACR20 was nearly identical (85% vs 84%), with a similar rate of adverse events.
The researchers pointed out “that there’s a potential cost benefit in developing countries where biologics aren’t as accessible,” he said, agreeing that “the big opportunity for a drug like leflunomide is outside the US, where you don’t have access to the drugs we take advantage of all the time.”
A meeting participant from Canada pointed out that rheumatologists there are “mandated to use it for PsA in combination with methotrexate before we can get a biologic, and for RA we can use it with Plaquenil [hydroxychloroquine] and methotrexate before we get a biologic, so we’re using it all the time.”
Asked about efficacy, the physician said the combination with methotrexate is “absolutely” efficacious. “It works really well” he said. “The problem is, you really have to watch the white cell count and liver function … and the half-life is long.”
Indeed, Dr. Ruderman said during his talk, the plasma half-life of teriflunomide, its active metabolite, is 15.5 days, which is challenging when adverse events occur. “And it’s a terrible drug in young women thinking about pregnancy because it’s teratogenic and stays around,” he said.
Leflunomide, which, notably, was “developed specifically for RA from the get-go” and not borrowed from another specialty, works by blocking de novo pyrimidine synthesis, Dr. Ruderman said. T-cell activation requires the upregulation of pyrimidine production (salvage pathways are insufficient); the “drug prevents that” by inhibiting an enzyme that catalyzes conversion of dihydroorotate to orotate, which, in turn, is converted to pyrimidine ribonucleotides, he explained.
Other potential mechanisms of action have been proposed — mainly, inhibition of tumor necrosis factor signaling and inhibition of kinase activity, including the JAK/STAT pathway — but “there’s not great data for any of them,” he said.
Loading vs Not Loading, and Its Role in PsA and Other Diseases
“We stopped loading years ago because at 100 mg for 3 days in a row, everyone has GI issues,” Dr. Ruderman said. “It may have made sense from a pharmacokinetic standpoint because [based on the long half-life] you could get to a higher drug level quicker, but not a practical standpoint, because patients would stop the drug — they couldn’t take it.” The first study to examine the necessity of loading leflunomide in a “prospective, careful way” was published in 2013. It randomized 120 patients to 100 mg or 20 mg for 3 days, followed by a 3-month open-label period of 20 mg, and found no clinical benefit with loading but more diarrhea and elevated liver enzymes.
“It tells us something about how we need to think about half-lives,” he said. “Maybe [loading is] not necessary because the biological effects are different than the drug levels.”
In the PsA space, in 2004, researchers reported a double-blind randomized trial in which 190 patients with active PsA and cutaneous psoriasis with at least 3% body surface area involvement were randomized to receive leflunomide (a loading dose followed by 20 mg/day) or placebo for 24 weeks. Almost 60% of leflunomide-treated patients, compared with 30% of placebo-treated patients, were classified as responders by the Psoriatic Arthritis Response criteria (P < .0001), “which is a soft endpoint” but was utilized at the time, Dr. Ruderman said. The researchers noted improvements in ACR20 and skin responses as well, and toxicity was similar to that reported in the RA studies.
However, approval was never sought, and the drug was infrequently prescribed, “because etanercept came out for this disease, and then adalimumab … and then the world changed,” he said.
More recently, a single-center, double-blind, randomized trial that included 78 Dutch patients with PsA tested leflunomide plus methotrexate vs methotrexate monotherapy and was published in The Lancet Rheumatology. After 16 weeks, mean Psoriatic Arthritis Disease Activity Score (PASDAS) had improved for patients in the combination therapy group in comparison with the monotherapy group (3.1 [standard deviation (SD), 1.4] vs 3.7 [SD, 1.3]; treatment difference, -0.6; 90% CI, -1.0 to -0.1; P = .025). The combination therapy group also achieved PASDAS low disease activity at a higher rate (59%) than that of the monotherapy group (34%; P = .019). Three patients in the combination therapy group experienced serious adverse events, two of which were deemed unrelated to leflunomide. The most frequently occurring adverse events were nausea or vomiting, tiredness, and elevated alanine aminotransferase. Mild adverse events were more common in the methotrexate plus leflunomide group.
In an interview after the meeting, Dr. Ruderman explained that in his practice, about 15 years ago, leflunomide was sometimes prescribed as an alternative to a biologic change for patients whose skin disease improved significantly with ustekinumab (Stelara) but who “suddenly had more joint symptoms that they didn’t have before.”
And “we’ve found ourselves a bit recently with the same sort of story, where patients are prescribed IL-23 inhibitors like Skyrizi [risankizumab] and Tremfya [guselkumab] and their skin does really well but now they’re having more joint symptoms than previously,” he said. “Our choices are to switch to a whole different biologic, or to think about adding something as an adjunct — and maybe leflunomide is a reasonable option.”
In the last 5 years, Dr. Ruderman noted, randomized trial data has been published on leflunomide in lupus nephritis induction, and in lupus nephritis maintenance, as well as in IgG4-related disease.
Dr. Ruderman disclosed consulting and/or drug safety monitoring board work for AbbVie, Amgen, Bristol-Myers Squibb, Janssen, Lilly, Merck, Novartis, NS Pharma, and UCB.
<!--$RCSfile: InCopy_agile.xsl,v $ $Revision: 1.35 $-->
<!--$RCSfile: drupal.xsl,v $ $Revision: 1.7 $-->
<root generator="drupal.xsl" gversion="1.7"> <header> <fileName>167164</fileName> <TBEID>0C04EDA3.SIG</TBEID> <TBUniqueIdentifier>MD_0C04EDA3</TBUniqueIdentifier> <newsOrJournal>News</newsOrJournal> <publisherName>Frontline Medical Communications</publisherName> <storyname>Leflunomide</storyname> <articleType>2</articleType> <TBLocation>QC Done-All Pubs</TBLocation> <QCDate>20240308T121854</QCDate> <firstPublished>20240308T123012</firstPublished> <LastPublished>20240308T123012</LastPublished> <pubStatus qcode="stat:"/> <embargoDate/> <killDate/> <CMSDate>20240308T123012</CMSDate> <articleSource>FROM RWCS 2024</articleSource> <facebookInfo/> <meetingNumber>4660-24</meetingNumber> <byline>Christine Kilgore</byline> <bylineText>CHRISTINE KILGORE</bylineText> <bylineFull>CHRISTINE KILGORE</bylineFull> <bylineTitleText>MDedge News</bylineTitleText> <USOrGlobal/> <wireDocType/> <newsDocType>News</newsDocType> <journalDocType/> <linkLabel/> <pageRange/> <citation/> <quizID/> <indexIssueDate/> <itemClass qcode="ninat:text"/> <provider qcode="provider:imng"> <name>IMNG Medical Media</name> <rightsInfo> <copyrightHolder> <name>Frontline Medical News</name> </copyrightHolder> <copyrightNotice>Copyright (c) 2015 Frontline Medical News, a Frontline Medical Communications Inc. company. All rights reserved. This material may not be published, broadcast, copied, or otherwise reproduced or distributed without the prior written permission of Frontline Medical Communications Inc.</copyrightNotice> </rightsInfo> </provider> <abstract/> <metaDescription>The Food and Drug Administration’s approval of leflunomide in September 1998 as a treatment for rheumatoid arthritis was sandwiched between the debuts of inflix</metaDescription> <articlePDF/> <teaserImage>300641</teaserImage> <teaser>Overlooked in the biologic era, it still has a place.</teaser> <title>Leflunomide: A Fresh Look at an Old Drug</title> <deck/> <disclaimer/> <AuthorList/> <articleURL/> <doi/> <pubMedID/> <publishXMLStatus/> <publishXMLVersion>1</publishXMLVersion> <useEISSN>0</useEISSN> <urgency/> <pubPubdateYear/> <pubPubdateMonth/> <pubPubdateDay/> <pubVolume/> <pubNumber/> <wireChannels/> <primaryCMSID/> <CMSIDs/> <keywords/> <seeAlsos/> <publications_g> <publicationData> <publicationCode>rn</publicationCode> <pubIssueName/> <pubArticleType/> <pubTopics/> <pubCategories/> <pubSections/> </publicationData> <publicationData> <publicationCode>im</publicationCode> <pubIssueName/> <pubArticleType/> <pubTopics/> <pubCategories/> <pubSections/> </publicationData> </publications_g> <publications> <term canonical="true">26</term> <term>21</term> </publications> <sections> <term canonical="true">53</term> <term>39313</term> </sections> <topics> <term canonical="true">289</term> <term>282</term> <term>241</term> <term>290</term> </topics> <links> <link> <itemClass qcode="ninat:picture"/> <altRep contenttype="image/jpeg">images/24012700.jpg</altRep> <description role="drol:caption">Dr. Eric M. Ruderman</description> <description role="drol:credit">Courtesy Michael Pollard</description> </link> </links> </header> <itemSet> <newsItem> <itemMeta> <itemRole>Main</itemRole> <itemClass>text</itemClass> <title>Leflunomide: A Fresh Look at an Old Drug</title> <deck/> </itemMeta> <itemContent> <p>The Food and Drug Administration’s approval of leflunomide in September 1998 as a treatment for rheumatoid arthritis was sandwiched between the debuts of infliximab (Remicade and biosimilars) and etanercept (Enbrel) in August and November of that year, the latter of which was so exciting that “within 2 months you couldn’t get [it],” recalled Eric M. Ruderman, MD. And “like every middle child, [leflunomide] was underloved, underappreciated, and largely dismissed.”</p> <p>Yet should it have been? Is it worth another look today? <br/><br/>[[{"fid":"300641","view_mode":"medstat_image_flush_left","fields":{"format":"medstat_image_flush_left","field_file_image_alt_text[und][0][value]":"Dr. Eric M. Ruderman of Northwestern University, Chicago","field_file_image_credit[und][0][value]":"Courtesy Michael Pollard","field_file_image_caption[und][0][value]":"Dr. Eric M. Ruderman"},"type":"media","attributes":{"class":"media-element file-medstat_image_flush_left"}}]]At the 2024 Rheumatology Winter Clinical Symposium, Dr. Ruderman reflected on some of the clinical trial data published after leflunomide’s approval that “got lost in the shuffle” of the rightful embrace of biologics in United States practice, and urged reconsideration of the loading strategy still advised in the drug’s labeling. <br/><br/>“I’m not telling you that you should be using [leflunomide] in place of biologics, instead of biologics, or before biologics … but it should be in your toolkit,” said Dr. Ruderman, professor of medicine and associate chief of clinical affairs in the division of rheumatology at Northwestern University Feinberg School of Medicine, Chicago. The drug “still has a role in RA, including in combination with methotrexate, and a potential role in other rheumatic diseases.”<br/><br/>“In our PsA clinic,” he noted, “we’ve actually not infrequently added leflunomide to some of the other agents we’ve been using.”<br/><br/></p> <h2>Key Findings Over the Years in RA</h2> <p>Leflunomide showed efficacy similar to that of sulfasalazine in a <span class="Hyperlink"><a href="https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(98)09403-3/abstract">randomized trial published in 1999</a></span> that used primary endpoints of tender/swollen joints and physician and patient global scores. Then, against methotrexate, it proved just as efficacious in achieving at least 20% improvement in American College of Rheumatology composite response criteria (ACR20) over 52 weeks, and in meeting endpoints similar to those of the sulfasalazine trial, in two trials, <span class="Hyperlink"><a href="https://jamanetwork.com/journals/jamainternalmedicine/fullarticle/485189">one published in 1999</a></span> and <span class="Hyperlink"><a href="https://academic.oup.com/rheumatology/article/39/6/655/1783994">another in 2000</a></span>. </p> <p>“So here were two big trials [comparing it with methotrexate] that suggested the drug was just as good as what had become our standard of care by that point,” Dr. Ruderman said. <br/><br/>Each of these three trials used a loading dose of 100 mg leflunomide for 3 days, followed by 20 mg daily. Sulfasalazine was initiated at 2 g and escalated over 4 weeks. Methotrexate was initiated in one of the trials at a dose of 7.5 mg, then increased to 15 mg in almost two-thirds of patients; in the other methotrexate trial the initial dose was 15 mg escalated over 3 months. <br/><br/>Side effects of leflunomide — GI issues, rash, alopecia (reversible), and elevated liver function tests — were similar across the trials, and represented “about the same toxicities as methotrexate,” he said. <br/><br/>Researchers then <span class="Hyperlink"><a href="https://www.acpjournals.org/doi/10.7326/0003-4819-137-9-200211050-00007">tested leflunomide as an add-on</a></span> to methotrexate in patients who had inadequate response, which “was a little bit daunting since we were still concerned about the toxicity of methotrexate at this point,” Dr. Ruderman said. “The idea that we’d take another drug with similar toxicities and add it on to the methotrexate was a little scary.”<br/><br/>But it worked. Patients on a mean background dose of 16.5 mg methotrexate were randomized to placebo or to a 2-day leflunomide loading dose followed by 10 mg/day that could be escalated at 8 weeks to 20 mg if needed. At 6 months, 19.5% and 46.2%, respectively, met ACR20 (<em>P</em> < .001), and “interestingly,” he said, “adverse events were pretty similar” between combination therapy and methotrexate monotherapy. <br/><br/>“This was very much like all the studies we’ve seen over the years with new biologics — they were all added to background methotrexate,” he said. “And the truth is, the [46%] response seen when adding leflunomide to background methotrexate wasn’t very different from the 50% [ACR20] response you tend to see when you add a biologic.”<br/><br/>However, despite the study’s conclusion that combination therapy provided significant benefit to patients with inadequate response to methotrexate alone, “the drug got lost, because everyone was prescribing the biologics,” Dr. Ruderman said. <br/><br/>He said he found only one study comparing leflunomide with a biologic. In a notably small but well-designed <span class="Hyperlink"><a href="https://bmcmusculoskeletdisord.biomedcentral.com/articles/10.1186/s12891-017-1673-3">study from Sri Lanka</a></span> published in 2017, 40 patients with an inadequate response to methotrexate were randomized to low-dose rituximab (500 mg x 2) or 20 mg/day leflunomide (no loading dose). At week 24, ACR20 was nearly identical (85% vs 84%), with a similar rate of adverse events.<br/><br/>The researchers pointed out “that there’s a potential cost benefit in developing countries where biologics aren’t as accessible,” he said, agreeing that “the big opportunity for a drug like leflunomide is outside the US, where you don’t have access to the drugs we take advantage of all the time.”<br/><br/>A meeting participant from Canada pointed out that rheumatologists there are “mandated to use it for PsA in combination with methotrexate before we can get a biologic, and for RA we can use it with Plaquenil [hydroxychloroquine] and methotrexate before we get a biologic, so we’re using it all the time.” <br/><br/>Asked about efficacy, the physician said the combination with methotrexate is “absolutely” efficacious. “It works really well” he said. “The problem is, you really have to watch the white cell count and liver function … and the half-life is long.”<br/><br/>Indeed, Dr. Ruderman said during his talk, the plasma half-life of teriflunomide, its active metabolite, is 15.5 days, which is challenging when adverse events occur. “And it’s a terrible drug in young women thinking about pregnancy because it’s teratogenic and stays around,” he said. <br/><br/>Leflunomide, which, notably, was “developed specifically for RA from the get-go” and not borrowed from another specialty, works by blocking de novo pyrimidine synthesis, Dr. Ruderman said. T-cell activation requires the upregulation of pyrimidine production (salvage pathways are insufficient); the “drug prevents that” by inhibiting an enzyme that catalyzes conversion of dihydroorotate to orotate, which, in turn, is converted to pyrimidine ribonucleotides, he explained. <br/><br/>Other potential mechanisms of action have been proposed — mainly, inhibition of tumor necrosis factor signaling and inhibition of kinase activity, including the JAK/STAT pathway — but “there’s not great data for any of them,” he said.<br/><br/></p> <h2>Loading vs Not Loading, and Its Role in PsA and Other Diseases</h2> <p>“We stopped loading years ago because at 100 mg for 3 days in a row, everyone has GI issues,” Dr. Ruderman said. “It may have made sense from a pharmacokinetic standpoint because [based on the long half-life] you could get to a higher drug level quicker, but not a practical standpoint, because patients would stop the drug — they couldn’t take it.” The first study to examine the necessity of loading leflunomide in a “prospective, careful way” was <span class="Hyperlink"><a href="https://academic.oup.com/rheumatology/article/52/6/1132/1835956">published in 2013</a></span>. It randomized 120 patients to 100 mg or 20 mg for 3 days, followed by a 3-month open-label period of 20 mg, and found no clinical benefit with loading but more diarrhea and elevated liver enzymes.</p> <p>“It tells us something about how we need to think about half-lives,” he said. “Maybe [loading is] not necessary because the biological effects are different than the drug levels.” <br/><br/>In the PsA space, in 2004, <span class="Hyperlink"><a href="https://onlinelibrary.wiley.com/doi/10.1002/art.20253">researchers reported</a></span> a double-blind randomized trial in which 190 patients with active PsA and cutaneous psoriasis with at least 3% body surface area involvement were randomized to receive leflunomide (a loading dose followed by 20 mg/day) or placebo for 24 weeks. Almost 60% of leflunomide-treated patients, compared with 30% of placebo-treated patients, were classified as responders by the Psoriatic Arthritis Response criteria (<em>P</em> < .0001), “which is a soft endpoint” but was utilized at the time, Dr. Ruderman said. The researchers noted improvements in ACR20 and skin responses as well, and toxicity was similar to that reported in the RA studies. <br/><br/>However, approval was never sought, and the drug was infrequently prescribed, “because etanercept came out for this disease, and then adalimumab … and then the world changed,” he said. <br/><br/>More recently, a single-center, double-blind, <span class="Hyperlink"><a href="https://www.thelancet.com/journals/lanrhe/article/PIIS2665-9913(22)00028-5/abstract#%20">randomized trial</a></span> that included 78 Dutch patients with PsA tested leflunomide plus methotrexate vs methotrexate monotherapy and was <span class="Hyperlink">published in </span><em>The Lancet Rheumatology</em>. After 16 weeks, mean Psoriatic Arthritis Disease Activity Score (PASDAS) had improved for patients in the combination therapy group in comparison with the monotherapy group (3.1 [standard deviation (SD), 1.4] vs 3.7 [SD, 1.3]; treatment difference, -0.6; 90% CI, -1.0 to -0.1; <em>P</em> = .025). The combination therapy group also achieved PASDAS low disease activity at a higher rate (59%) than that of the monotherapy group (34%; <em>P</em> = .019). Three patients in the combination therapy group experienced serious adverse events, two of which were deemed unrelated to leflunomide. The most frequently occurring adverse events were nausea or vomiting, tiredness, and elevated alanine aminotransferase. Mild adverse events more common in the methotrexate plus leflunomide group.<br/><br/>In an interview after the meeting, Dr. Ruderman explained that in his practice, about 15 years ago, leflunomide was sometimes prescribed as an alternative to a biologic change for patients whose skin disease improved significantly with ustekinumab (Stelara) but who “suddenly had more joint symptoms that they didn’t have before.” <br/><br/>And “we’ve found ourselves a bit recently with the same sort of story, where patients are prescribed IL-23 inhibitors like Skyrizi [risankizumab] and Tremfya [guselkumab] and their skin does really well but now they’re having more joint symptoms than previously,” he said. “Our choices are to switch to a whole different biologic, or to think about adding something as an adjunct — and maybe leflunomide is a reasonable option.”<br/><br/>In the last 5 years, Dr. Ruderman noted, randomized trial data has been published on leflunomide in <span class="Hyperlink"><a href="https://link.springer.com/article/10.1007/s10067-018-4348-z">lupus nephritis induction</a></span>, and in <span class="Hyperlink"><a href="https://ard.bmj.com/content/81/11/1549">lupus nephritis maintenance</a></span>, as well as in <span class="Hyperlink"><a href="https://www.sciencedirect.com/science/article/abs/pii/S004901722030010X?via%3Dihub">IgG4-related disease</a></span>.<br/><br/>Dr. Ruderman disclosed consulting and/or drug safety monitoring board work for AbbVie, Amgen, Bristol-Myers Squibb, Janssen, Lilly, Merck, Novartis, NS Pharma, and UCB.</p> </itemContent> </newsItem> <newsItem> <itemMeta> <itemRole>teaser</itemRole> <itemClass>text</itemClass> <title/> <deck/> </itemMeta> <itemContent> </itemContent> </newsItem> </itemSet></root>
FROM RWCS 2024
