With luck, maybe Ms. Ahmed’s son could follow in his aunt’s footsteps and get a stem cell transplant from a compatible family donor. But while little Yusuf Saeed has a twin sister of his own, she wasn’t a match. Without another treatment option, he’d face the prospect of a lifetime not only cut short but burdened by multiple monthly transfusions and severe limitations.
Then came glimpses of hope. One of Yusuf’s physicians at Cohen Children’s Medical Center in Long Island, New York, told Yusuf’s mother about a new kind of gene therapy on the horizon. But it took time to get FDA approval. Yusuf grew older, heading toward his teenage years, when regular transfusions would be a huge burden. “He’s turning 5 and 6, and there’s nothing,” Ms. Ahmed recalled, and the family worried.
Finally, the FDA approved the one-time treatment — betibeglogene autotemcel (beti-cel, Zynteglo) in 2022. By January 2024, the hospital was ready to treat Yusuf. At age 8, he became the first patient in the state of New York to undergo gene therapy for beta thalassemia.
A medical team infused Yusuf with his own stem cells, which had been genetically engineered to boost production of hemoglobin and prevent thalassemia’s devastating effects.
There are caveats about the treatment. It’s an extraordinarily expensive therapy that can be performed at only a few institutions. And it’s so brand new that caveats may not even have appeared yet. Yet, for kids like Yusuf, the gene therapy could transform a life.
“We feel like a weight has been lifted,” Ms. Ahmed said in an interview. “It’s something we’ve been waiting for.”
Anemia Becomes a Lifetime Threat
Among all genetic diseases, thalassemia stands alone. It’s the most common condition caused by a single gene, according to Hanny Al-Samkari, MD, a hematologist/clinical investigator at Massachusetts General Hospital and associate professor of medicine at Harvard Medical School, in Boston, Massachusetts.
Millions of people have the thalassemia trait, especially in southern Europe, the Middle East, southeast Asia, and Africa, Dr. Al-Samkari said. (Yusuf’s parents are from Pakistan.)
The trait, which appears to provide protection against malaria, may cause mild anemia in some cases but is otherwise harmless. However, a child born to parents with the same kind of trait has a high risk of developing alpha thalassemia or beta thalassemia. Like his aunt, Yusuf developed beta thalassemia, which is generally more severe. Yusuf’s bleeding disorder requires him to be transfusion-dependent.
In these patients, the disease disrupts the production of red blood cells in the bone marrow, Dr. Al-Samkari said. Hemoglobin levels can fall to 7 or 8 g/dL, compared with the normal levels of 12-16 g/dL in adults. “They’re chronically anemic, and that low hemoglobin that leads to things you associate with anemia: fatigue, reduced exercise tolerance, mind fog, challenges with work or school, and hypersomnolence.”
In addition, the bones become thinner and more brittle, he said, leading to fractures.
Transfusions are one treatment option, but they’re needed for a lifetime and cause their own problems, such as iron overload. Care of thalassemia patients “becomes quite complex and quite challenging for both families and medical institutions,” Alexis A. Thompson MD, MPH, chief of hematology at Children’s Hospital of Philadelphia, Pennsylvania, said in an interview.
Yusara Ahmed remembers her sister’s endless visits to the hospital after she was diagnosed at age 4. “We were all very traumatized by the hospital environment,” she said. But good news came in 2008, a few years later, when her sister was able to get a stem cell transplant from their brother.
But while stem cell transplants can be curative, most children don’t have a relative who can be a suitable match as a donor, Dr. Thompson said. Now, gene therapy offers another option, by turning a patient into his or her own matched donor.