The Food and Drug Administration has approved the first gene therapy in the United States to treat sickle cell disease — a historic move that could change the lives of more than 100,000 Americans living with the inherited blood disorder. The decision, announced on , clears the way for Vertex Pharmaceuticals and CRISPR Therapeutics to begin offering the treatment, called Casgevy, to eligible patients as early as next month. What makes this so remarkable isn’t just the science — it’s the fact that this therapy targets the root cause of a disease that has haunted Black communities for generations, often with little more than painkillers and blood transfusions as options.
How the Therapy Works
Unlike traditional treatments that manage symptoms, Casgevy rewrites a patient’s own blood stem cells to produce fetal hemoglobin — the kind babies naturally make before switching to adult hemoglobin. In people with sickle cell, a genetic mutation causes red blood cells to twist into rigid, sickle shapes, clogging vessels and triggering excruciating pain episodes, organ damage, and early death. The therapy uses CRISPR-Cas9 gene editing to disable a gene called BCL11A, which normally shuts off fetal hemoglobin production after birth. Let that sink in: scientists are turning back a biological clock inside a patient’s body.
The process begins with harvesting bone marrow stem cells from the patient. Those cells are edited in a lab, then infused back into the patient after they’ve undergone intensive chemotherapy to clear out their existing bone marrow. It’s not simple. It’s not cheap — the treatment costs $2.2 million per patient. But for many, it’s the first real shot at freedom from the cycle of hospitalizations and chronic pain.
A Long Road to Approval
The path to this approval wasn’t smooth. Clinical trials involving 31 patients showed that 29 of them — nearly 94% — went at least a year without a severe pain crisis, compared to just 16% in the control group. That’s not just statistically significant; it’s life-altering. One participant, 23-year-old Shanice Jones from Atlanta, described her life before treatment: "I missed three years of college because I was in the hospital. I lost jobs. I stopped making plans." After receiving Casgevy in 2021, she’s now working full-time and planning to go back to school.
But access is going to be a huge hurdle. The therapy requires specialized centers with expertise in stem cell transplants and gene editing — fewer than 50 such facilities exist in the U.S. And insurance coverage remains uncertain. Medicaid programs in states like Mississippi and Alabama, where sickle cell is most prevalent, are already scrambling to figure out how to pay for it.
Who Gets Left Behind?
Here’s the uncomfortable truth: sickle cell disease disproportionately affects Black Americans, yet funding for research and care has lagged behind other genetic disorders with similar prevalence. Cystic fibrosis, which affects mostly white patients, received over $100 million in federal research funding in 2022. Sickle cell got about $20 million. That disparity isn’t just historical — it’s systemic.
"This therapy is a triumph of science," said Dr. Linda Okafor, a hematologist at Johns Hopkins Hospital. "But if we don’t build the infrastructure to deliver it equitably, we’re just replacing one kind of suffering with another — the suffering of being denied access because of where you live or how much you earn."
What Comes Next?
Another gene therapy for sickle cell, developed by Bluebird Bio and called Lyfgenia, is expected to receive FDA approval in early 2024. That means competition — and possibly lower prices. Meanwhile, researchers are already exploring whether similar gene-editing techniques could treat thalassemia, another inherited blood disorder.
But the biggest question isn’t scientific. It’s moral. Can the U.S. health system afford to treat 100,000 people with a $2.2 million therapy? And if not, who decides who gets treated first?
Historical Context: A Disease Long Ignored
Sickle cell disease was first described in 1910 by Dr. James Herrick, a Chicago physician who noted the "sickle-shaped" red blood cells in a dental student from Grenada. For decades, it was dismissed as a "Black disease" — a term that carried racist assumptions and led to neglect. Even in the 1970s, when newborn screening programs began, many states refused to fund them. It wasn’t until 1972 that Congress passed the Sickle Cell Anemia Control Act, after years of activism by Black patient advocates.
Today, the average life expectancy for someone with sickle cell in the U.S. is just 54 years — 20 years shorter than the national average. Children still die from stroke or infection because they lack access to penicillin prophylaxis or hydroxyurea, a cheap, decades-old drug that reduces crises by 50%.
So while Casgevy is a scientific milestone, it’s also a mirror. It forces us to ask: Why did it take this long? And why did it take gene editing — a billion-dollar technology — to finally treat a disease that’s been here since the transatlantic slave trade?
Frequently Asked Questions
Who is eligible for Casgevy?
Patients must be 12 years or older with a history of severe vaso-occlusive crises — typically three or more hospitalizations in the past two years. They must also be in good enough health to withstand the chemotherapy required before the gene therapy infusion. Not everyone qualifies, and doctors will evaluate each case individually based on organ function and prior treatments.
How long does the treatment take, and what’s the recovery like?
The entire process takes about six weeks. Patients spend 10–14 days in the hospital for the chemotherapy and infusion, then remain nearby for another four to six weeks for monitoring. Side effects include infertility (nearly universal due to chemo), low blood counts, and infection risk. Recovery is slow, and patients need lifelong follow-up to monitor for potential long-term gene-editing side effects — which are still unknown.
Will insurance cover Casgevy?
Some private insurers have already signaled they’ll cover it, but Medicaid programs in high-prevalence states are still negotiating. The Centers for Medicare & Medicaid Services (CMS) has not yet made a national determination. States may need to apply for waivers or use special funding streams. Without federal guidance, access could vary wildly by zip code — creating a two-tiered system.
Are there alternatives to gene therapy?
Yes. Hydroxyurea, a daily pill, reduces pain crises by up to 50% and is widely available. Blood transfusions and newer drugs like crizanlizumab and voxelotor also help. Bone marrow transplants from matched siblings can cure the disease but are only an option for about 15% of patients. Gene therapy offers hope to the rest — but at a steep price, both financially and physically.
What does this mean for global health?
Sickle cell affects 300,000 babies annually worldwide — 80% of them in sub-Saharan Africa. The $2.2 million price tag makes Casgevy inaccessible there. Researchers are working on cheaper, injectable versions using different delivery systems, but those are still years away. This approval highlights a global inequity: life-saving gene therapies may be available in wealthy nations while children in Nigeria or the Democratic Republic of Congo still die from preventable complications.
Could this lead to gene editing for other conditions?
Absolutely. Casgevy’s approval sets a regulatory precedent for other gene therapies targeting monogenic diseases — like Duchenne muscular dystrophy, Huntington’s, or certain forms of inherited blindness. The FDA’s review process for this therapy will shape how future gene edits are evaluated. But experts warn: we must proceed carefully. Editing human DNA carries risks we don’t fully understand, especially when applied to embryos or non-life-threatening conditions.