The Food and Drug Administration on Friday approved a gene-editing therapy that's seen success in treating the most severe form of the disease.
Casgevy, manufactured by Vertex Pharmaceuticals and CRISPR Therapeutics, is the first approved therapy based on CRISPR, the gene editing tool that won its inventors the Nobel Prize in 2020. Also approved was another gene therapy made by Bluebird Bio that works differently.
Casgevy was approved in the United Kingdom last month after seeing a successful global trial in which 28 out of 29 patients reported being free of severe pain.
The gene therapy is a breakthrough against sickle cell — which previously had only one known permanent cure: a bone marrow transplant from a matched donor — and could make a difference for many lives in Florida.
The Sunshine State boasts a yearly average of about 7,000 new cases a year, twice that of the national average, according to a 2023 report by the Florida Agency for Health Care Administration.
South Florida and Central Florida lead the state's average diagnosis per year, according to the report.
Sickle cell is most common among Black people and 1 in 365 Black babies are born with the disease nationally. Scientists believe being a carrier of the sickle cell trait helps protect against severe malaria, so the disease occurs more often in mosquito-prone regions such as Africa or in people whose ancestors lived in those places.
"Sickle cell disease is a common genetic disorder in certain ethnicities. The African American population is No. 1, but we are seeing a lot of other ethnicities such as Asian and patients from Iran and Iraq," said Dr. Asad Sheikh, medical director at the Orlando Heath Cancer Institute. "Florida is quite a hodgepodge of all these ethnicities."
The disease causes a shortage of red blood cells and a lack of hemoglobin, which grabs oxygen molecules and binds them to cells. As a result, those with sickle cell experience chronic pain.
No donor is required for the gene therapies, which permanently change DNA in the patient’s blood cells.
"What Casgevy does is increase the amount of fetal hemoglobin in the body," Sheikh said.
The fetal form of hemoglobin is present at birth. It’s the adult form that’s defective in people with sickle cell. CRISPR is used to knock out a gene in stem cells collected from the patient.
While impactful, the treatment may not have an immediate impact in the Central Florida area and its large pool of patients, Sheihk said.
“It's going to take up to several years for the average sickle cell patient to have access to this type of highly advanced therapy," he said.
The first limitation is the expense. Casgevy is going for $2.2 million.
Experts also warned that cost could be a hurdle. The list price for Bluebird Bio is $3.1 million and for Vertex, $2.2 million. What patients might pay will depend on insurance coverage and other factors. To help cover the cost, the U.S. Centers for Medicare and Medicaid Services announced a plan that aims to establish partnerships with state Medicaid agencies and drug companies.
According to a report by the American Medical Association, 70% of patients identify themselves as disabled. Additionally, low employment rates have also been reported along with that disabled status. The report concludes these patients are likely to have lower earnings.
Additionally, a transplant center is required to administer Casgevy. Only five in the state as listed by the National Alliance of Sickle Cell Centers. Orlando Health is not listed but has a transplant center, Sheihk said, but far more will be necessary to make the treatment accessible.
"We need to create more transplant centers in Central Florida. And on top of that, we need to employ a lot of manpower for this type of gene editing therapy,” Sheikh said.
What patients might pay will depend on insurance coverage and other factors. To help cover the cost, the U.S. Centers for Medicare and Medicaid Services announced a plan that aims to establish partnerships with state Medicaid agencies and drug companies.
Even with the limitations Casgevy has in accessibility, Sheikh still sees the FDA approval as a huge first step in eradicating sickle cell.
The FDA’s approval is the first for Bluebird’s treatment, called Lyfgeni. It aims to add copies of a modified gene, which helps red blood cells produce “anti-sickling” hemoglobin that prevents or reverses misshapen cells.
When patients get the Lyfgeni treatments, stem cells are removed from their blood and sent to a lab. Before getting the altered cells back, they must undergo chemotherapy. The process requires at least two hospitalizations, one lasting four to six weeks.
The list price for Lyfgeni is about $3.3 million.
Information from the Associated Press was used in this report.
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