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The United States has given its approval for two gene therapies to be used in the treatment of sickle cell disease.
Science & Health

The United States has given its approval for two gene therapies to be used in the treatment of sickle cell disease.

On Friday, the U.S. Food and Drug Administration (FDA) granted approval for two gene therapies to treat sickle cell disease. This includes the first-ever treatment that utilizes CRISPR gene editing technology, which has been a major breakthrough in the field.

The organization gave the green light for Lyfgenia, developed by bluebird bio, as well as a distinct therapy known as Casgevy from the collaboration of Vertex Pharmaceuticals and CRISPR Therapeutics.

Both treatments were authorized for individuals 12 years and older.

The Vertex/CRISPR genetic therapy utilizes an innovative gene editing technique, which earned its creators the 2020 Nobel Prize.

Sickle cell disease is an inherited blood disorder that causes pain and can be disabling, potentially resulting in early death. It is estimated that 100,000 individuals in the United States have this disease, with the majority being of Black ethnicity.

Sickle cell disease causes the production of defective, crescent-shaped hemoglobin, which hinders the red blood cells’ ability to effectively transport oxygen to the body’s tissues.

The sickle cells have a tendency to clump together, potentially obstructing small blood vessels and resulting in severe pain. This can also increase the risk of strokes and organ dysfunction.

The shares of CRISPR therapeutics listed in the U.S. increased by 1.6%, while the stock of Vertex Pharmaceuticals decreased by 1.4%. Trading for bluebird bio shares was paused before the announcement.

The creators of both therapies have marketed them as single-use remedies, yet there is limited information on the duration of their effectiveness. The sole extended treatment option for sickle cell disease is a bone marrow transplant.

Dr. Sharl Azar, the medical director of the Comprehensive Sickle Cell Disease Treatment Center at Massachusetts General Hospital, stated that he is hesitant to refer to them as a cure. He instead prefers to call them transformative therapy because even after undergoing gene therapy, patients will still have sickle cell disease.

Bluebird bio has developed a treatment for sickle cell disease that involves using altered genes to restore normal hemoglobin production in red blood cells. This is achieved by introducing these modified genes into the body using disabled viruses.

For Vertex’s therapy, patients must have stem cells harvested from their bone marrow. The cells are then sent to manufacturing facilities where they are edited using CRISPR/Cas9 technology. Once the cells are incubated, they are infused back into the patient during a month-long hospital stay.

Both gene treatments may require multiple months and include a strong chemotherapy regimen, which carries the potential risk of causing infertility.

According to Dr. Azar, while not everyone who receives chemotherapy will experience infertility, the majority of patients will.

According to Dr. Azar, fertility preservation techniques such as freezing eggs and sperm banking can help mitigate the risks. However, insurance coverage for these methods is only available to cancer patients undergoing chemotherapy, not those receiving gene therapy.

He stated that the cost out-of-pocket could reach up to $40,000.

According to documents released prior to an October meeting of an expert panel, FDA staff have expressed concerns about unintended changes to the genome as a result of Vertex’s therapy.

The company intends to evaluate any potential long-term safety hazards by conducting a follow-up study lasting 15 years after receiving approval.

The use of CRISPR technology by Vertex is currently being reviewed by the FDA for a different blood disorder, transfusion-dependent beta thalassemia. A decision is anticipated by March 30.