FDA weighs risks and benefits of CRISPR therapy for sickle cell disease

A panel of advisors of the Food and Drug Administration on Tuesday (Oct 31) held a day-long meeting grappling with potential risks posed by a novel therapy for sickle cell disease, a rare blood disorder that affects a significant population globally.

If green-lit by the FDA, it could be a groundbreaking solution for many individuals battling severe forms of the rare blood disorder.

A novel therapy

Add WION as a Preferred Source

The therapy called exa-cel, which has been developed by Vertex Pharmaceuticals, harnesses CRISPR gene editing technology to potentially cure sickle cell disease.

As per a press release by Vertes, the FDA is expected to decide on exa-cel by December 8.

Documents released before Tuesday's meeting show that the FDA concurred with the company's portrayal of the therapy's trials, acknowledging the "strongly positive results".

Speaking at the meeting, Dr Nicole Verdun, head of the FDA's Office of Therapeutics Products, said: "It is an exciting time in cell and gene therapy that we are beginning to address some of this unmet need in a variety of diseases. Exa-cel has been studied for treatment of sickle cell disease with severe vaso-occlusive crises and has shown efficacy and safety."

Throughout the discussion, the FDA, as per CBS News, emphasised the importance of minimising unintended gene alterations, raising concerns about potential off-target editing and the associated risks.

"If the gene happens to play an essential role in cell function, then such unintended edits can be deleterious. These edits can also increase the risk of cancer," said the FDA's Komudi Singh, a bioinformatics reviewer for the agency.

However, experts underscored the absence of concrete evidence indicating adverse effects from unintended changes.

As per Dr Daniel Bauer, a researcher at Boston Children's Hospital, "Theoretically, could it? Yes. Is there evidence to suggest that it does? I would say no. But this hasn't really been done very much. We need to be humble and open to learning from these brave patients who are participating."

Largely supporting the treatment, committee members advocated for continued vigilance and long-term monitoring to fully grasp the treatment's impact.

Sickle cell disease

In the USA alone, around 100,000 people, predominantly from Black communities, are affected by sickle cell disease, according to estimates by the CDC.

Currently, blood and bone marrow transplants are the only available cures for this disease.

These too, are accessible to only a small fraction of patients as they depend on finding close genetic matches to them.

Sickle cell disease causes a range of debilitating complications, including agonising vaso-occlusive crises — where blood flow is blocked in the body — described as "bone-crushing pain" by one patient.

(With inputs from agencies)