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World's first gene therapy for sickle cell approved in the UK

November 20, 2023

Britain's Medicines and Healthcare products Regulatory Agency last week approved Casgevy as the world's first therapy to use CRISPR technology to treat sickle cell disease and β-thalassemia in patients 12 years and older. (Cambell, 2023)

In the U.S., the FDA is evaluating the same treatment and expects to make a decision by December 8. (Hunt, 2023)

Sickle cell disease, which can result in attacks of debilitating pain, is more prevalent in people with an African or Caribbean family background. β-thalassemia mostly affects people of Mediterranean, South Asian, Southeast Asian and Middle Eastern origin (Hunt, 2023).

“Both sickle cell disease and β-thalassemia are painful, life-long conditions that in some cases can be fatal. To date, a bone marrow transplant—which must come from a closely matched donor and carries risk of rejection—has been the only permanent treatment option,” said Julian Beach, the interim executive director of healthcare quality and access at the MHRA. (Hunt, 2023)

In clinical trials, researchers found that Casgevy restored healthy hemoglobin production in the majority of participants with sickle-cell disease and transfusion-dependent β -thalassemia, relieving disease symptoms (Campbell, 2023).

Casgevy, manufactured by Vertex Pharmaceuticals, works by editing the faulty gene in a patient’s bone marrow stem cells allowing for the production of functioning hemoglobin. Stem cells are harvested from bone marrow, then a gene is edited in the cells in a lab. Patients must then undergo a conditioning treatment, which can involve an immunosuppressing drug, radiotherapy or chemotherapy, to prepare the bone marrow before the modified cells are infused back into the patient. After infusion, patients may need to spend at least 30 days in hospital for the treatment to take full effect. (Hunt, 2023; Campbell, 2023)

• In a clinical trial of Casgevy for sickle cell disease, 28 of the 29 patients experienced no episodes of major pain, and averted hospitalization, for at least a year afterwards.
• When the treatment was used for those with β-thalassemia, 39 of the 42 trial participants did not require a red blood cell transfusion for at least 12 months after receiving Casgevy. (Campbell, 2023)

Sources:

Campbell, D. (2023, November 16). The Guardian. UK medicines regulator approves gene therapy for two blood disorders. https://www.theguardian.com/society/2023/nov/16/uk-medicines-regulator-approves-casgevy-gene-therapy-for-two-blood-disorders-sickle-cell

Hunt, K. (2023, November 16). CNN. CRISPR treatment has been greenlit in UK in global first. Here's who it could help. https://www.cnn.com/2023/11/16/health/uk-casgevy-approval-crispr-gene-editing-sickle-cell-scn/index.html