A gene editing treatment considered a game-changer for people living with sickle cell disease is under consideration to be approved in the United States before the end of 2023.
The disease is an inherited blood disorder that can be potentially deadly and often represents a lifetime of pain for patients.
An advisory committee to the U.S. Food and Drug Administration (FDA) will decide on Tuesday, October 31, 2023 if a new gene editing treatment's safety data is acceptable, according to a report by the New York Times.
The treatment, developed by Vertex Pharmaceuticals and CRISPR Therapeutics, involves the gene editing tool known as clustered regularly interspaced short palindromic repeats (CRISPR), used to selectively modify the DNA of living organisms.
When applied to a sickle cell patient, the technique activates a gene that can produce normally functioning blood cells. Vertex reported that treated patients during clinical trials stopped seeing symptoms of the disease, and appeared to be cured.
If the data satisfies the committee and it decides additional study is unnecessary, the FDA will decide whether to approve it on December 8.
How does the treatment work?
The treatment starts with the removal of stem cells from the blood — and the cells are sent for treatment. This stage is followed by intense chemotherapy to clear the bone marrow before the treated cells are injected into the patient. The patient is then required to stay at the hospital for at least one month while the treated cells repopulate the bone marrow.
According to the NYT report, there are still questions about how quickly production can scale. Notably, Vertex's sickle cell disease treatment is expensive and expected to cost millions of dollars per patient.
Also, the treatment and care needed for a successful procedure can only be administered by doctors who have expertise in a number of advanced techniques.
Who will get treatment?
The cocktail of problems the new treatment already faces will not come as a relief for millions of patients who live in developing countries and are less likely to be able to afford the treatment.
More than 66% of the 120 million people affected worldwide by sickle cell disease live in Africa, especially Nigeria, according to the World Health Organisation (WHO) in 2022. An estimated 1,000 children are born with the disease every day on the continent, and more than half of them die before they reach the age of five, usually from infection or severe anaemia.
The only other known cure for sickle cell disease currently is a blood and bone marrow transplant — finding a donor can be an impossible task. But the success of the Vertex treatment may open the door for similar treatments.
Another application for sickle cell gene therapy treatment, by Bluebird Bio, will be decided by the FDA on December 20, while two other companies and an academic centre are also testing their own sickle cell gene therapy treatments.
Vertex is also developing another ambitious treatment that would deliver gene editing in a pill.