The world’s first gene therapy for sickle cell disease has been approved in Britain

This microscope photo provided on Oct. 25 shows crescent-shaped red blood cells from a sickle cell disease patient in 1972. (Dr. F. Gilbert/CDC via AP, File )
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LONDON — Britain’s medicines regulator has authorized the world’s first gene therapy treatment for sickle cell disease, in a move that could offer relief to thousands of people with the crippling disease in the U.K.

In a statement Thursday, the Medicines and Healthcare Regulatory Agency said it approved Casgevy, the first medicine licensed using the gene editing tool CRISPR, which won its makers a Nobel prize in 2020.

The agency approved the treatment for patients with sickle cell disease and thalassemia who are 12 years old and over. Casgevy is made by Vertex Pharmaceuticals (Europe) Ltd. and CRISPR Therapeutics. To date, bone marrow transplants, extremely arduous procedures that come with very unpleasant side effects, have been the only long-lasting treatment.

“The future of life-changing cures resides in CRISPR based (gene-editing) technology,” said Dr. Helen O’Neill of University College London.

“The use of the word ‘cure’ in relation to sickle cell disease or thalassemia has, up until now, been incompatible,” she said in a statement, calling the MHRA’s approval of gene therapy “a positive moment in history.”

Both sickle cell disease and thalassemia are caused by mistakes in the genes that carry hemoglobin, the protein in red blood cells that carry oxygen.

The new medicine, Casgevy, works by targeting the problematic gene in a patient’s bone marrow stem cells so that the body can make properly functioning hemoglobin.

Patients first receive a course of chemotherapy, before doctors take stem cells from the patient’s bone marrow and use genetic editing techniques in a laboratory to fix the gene. The cells are then infused back into the patient for a permanent treatment. Patients must be hospitalized at least twice — once for the collection of the stem cells and then to receive the altered cells.