Slow Rollout for Sickle Cell Gene Therapies

Olaide Adekanbi has been struggling with sickle cell disease all her life. “It’s almost like I’m battling myself,” says Adekanbi, 29, who lives in Boston. “Sort of like a dark, I don’t know if you’d call it like evil within, [but] sometimes it feels like [it].” The rare genetic blood disease is caused by a genetic mutation that causes red blood cells to become deformed, sickle-shaped. These misshapen cells clog blood vessels, damaging vital organs and causing unpredictable, debilitating attacks of pain. “It gets to the point sometimes where you’re like, ‘I cannot continue living this way,’ ” she says. “You feel like you’re losing your mind. Because sometimes I just can’t move. I just lay in one spot and try to distract myself from the pain.” So Adekanbi was thrilled when, in late 2023, the Food and Drug Administration approved the first genetic treatments for sickle cell, a disease that disproportionately affects Black people like her and has long been neglected by medical science. “I’m very excited for the possibilities,” she says. “This is probably the best time in history right now for sickle cell patients.”

But Adekanbi is unsure about whether she wants to proceed with either of the two approved genetic treatments. One big hesitation is over the chemotherapy needed to make room for genetically altered cells in her bone marrow. Those cells have been modified to alleviate the symptoms of the disease. But the chemotherapy would endanger her chances of having kids. “I know I would like to have children in the … future," she says. "And so I’m really nervous about the process your body goes through in order to be able to go through the gene therapy process — how that will affect fertility.” And Adekanbi’s far from alone in wondering what to do. While there’s a lot of excitement about the treatments among sickle cell patients and those suffering from a related disorder known as beta thalassemia, only about 60 of the thousands of patients eligible for the treatment have started the process.

Adekanbi says she would try to freeze some of her eggs if she decides to proceed. But she and other potential patients are concerned about more than their fertility. The treatments also are grueling and complicated in other ways. “You could be in the hospital for months,” says Melissa Creary, who studies sickle cell at the University of Michigan School of Public Health. “Even if you’re not in the hospital, you’ll have to be nearby the hospital, which could or could not be in the state that you live in. And then once therapy is finished, there is a very complex process of follow-up for many, many months, again potentially in a state that you don’t live in.”

The treatments are very expensive, costing between $2.2 million and $3.1 million for each patient. “The cost continues to be a huge barrier ... in terms of getting it to the people who need it the most,” Creary says. And some patients worry about possible long-term risks, according to Dr. Lewis Hsu, chief medical officer of the Sickle Cell Disease Association of America. “What’s going to happen to me 10 to 20 years out? Will I have failure of the gene therapy products? They won’t be persisting in my system for that long? Or will there be some secondary leukemia?” Hsu says. “We don’t have good information right now because nobody’s been out that long.”

For their part, Vertex Pharmaceuticals of Boston and Bluebird Bio of Somerville, Mass., which make the treatments, say both therapies appear safe so far. And while it’s not surprising that it’s taking time to get the treatments widely accepted, given how complicated and expensive they are, both companies say interest is increasing fast. Dozens of hospitals have signed up to provide the treatments, and more are coming online every day, the companies say. In addition, the companies are working to help patients afford the treatments and related care, and more government and private insurers are paying for it. “We do see a lot of traction pretty much on par with what we thought would be the interest level. So we’re very encouraged with what we’re seeing,” says Andrew Obenshain, Bluebird Bio’s chief executive officer. “The hospitals are set up and ready to treat. The payors are paying for it. And the patients are interested.”