The US Food and Drug Administration (FDA) achieved a milestone on Friday by approving a groundbreaking gene-editing therapy designed to address sickle cell disease (SCD), marking the inaugural approval of CRISPR gene editing by federal regulators. 

The FDA authorized two novel treatments for SCD: Casgevy and Lyfgenia, The Hill reported.

Casgevy is the outcome of a collaboration between Vertex Pharmaceuticals and CRISPR Therapeutics. The innovative treatment involves utilizing the patient's own stem cells, which are then genetically edited to enhance fetal hemoglobin production before being reintroduced into the individual.

Lyfgenia is another cell-based gene therapy that genetically modifies stem cells to create HbAT87Q, a hemoglobin that prevents sickle-shaped red blood cells.

More Targeted Treatment

Sickle cell disease is an inherited blood disorder characterized by misshapen half-moon red blood cells, causing blockages in blood vessels and triggering excruciating crises.

Casgevy leverages CRISPR technology to edit a person's DNA, activating fetal hemoglobin, a protein that typically declines after birth. In clinical trials, Casgevy demonstrated efficacy by eliminating pain crises in the majority of patients.

Fetal hemoglobin plays a pivotal role in preventing the characteristic sickle shape of red blood cells, which is the root cause of complications and pain associated with SCD. 

Around 100,000 people in the US, predominantly of black descent, grapple with the challenges of SCD. Casgevy has secured FDA approval for SCD patients aged 12 and above.

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Dr. Nicole Verdun, Director of the Office of Therapeutic Products within the FDA's Center for Biologics Evaluation and Research, expressed enthusiasm about advancing treatments for individuals severely affected by SCD. She emphasized that gene therapy holds promise for more targeted and effective treatments, "especially for individuals with rare diseases where the current treatment options are limited," according to CNBC.

While Casgevy is administered only once, the entire process spans months. Blood stem cells are extracted, genetically modified in Vertex's lab, and then reintroduced into patients after chemotherapy. The recovery process involves spending weeks in the hospital.

Pricing Concerns

Vertex estimates that approximately 16,000 people with severe cases of sickle cell disease will be eligible for the treatment. However, despite its potential, analysts express concerns about the treatment's complexity, the risk of infertility, and its potential cost barriers. 

The firm has set the price of the SCD treatment at $2.2 million per patient. Due to the intricate procedure, its administration will be limited to specific health facilities, such as academic medical centers. Nine healthcare facilities are prepared to commence the Casgevy administration, with additional facilities anticipated to join in the coming weeks.

Jennifer Doudna of the University of California, Berkeley, a pivotal figure in the discovery of CRISPR gene editing, is actively working to simplify gene-editing treatments. Biotech companies involved in these treatments are collaborating with private and public insurers to facilitate coverage. Advocates highlight potential cost savings compared to a lifetime of sickle cell complications.

While celebrating the groundbreaking approval, there are concerns about potential long-term effects and "off-target" errors in the DNA. For 15 years, the firms will track all treated individuals to evaluate the gene-editing SCD treatment's durability, lifetime, and long-term problems, as reported by NPR.

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