FDA Approves CRISPR Gene Therapy to Treat Blood Disorder

The U.S. Food and Drug Administration (FDA) has approved CRISPR gene editing cell therapy to treat a rare inherited blood disorder called transfusion-dependent beta-thalassemia (TDT).

CRISPR Therapeutics and Vertex Pharmaceuticals’ gene editing cell therapy, branded as Casgevy, has officially been approved to treat TDT — a rare inherited blood disorder that requires regular blood transfusions — in patients 12 and over.

Vertex announced Tuesday that it had been given FDA approval more than two months ahead of its original expected action date, and just over a month after the same treatment to treat sickle cell disease was approved.

The treatment is a groundbreaking, Nobel prize-winning therapy that allows for DNA to be cut in specific places so sequences can be added, deleted, or replaced with healthy DNA.

Approximately 1,000 people aged 12 and older suffer from TDT in the United States and are now eligible for this treatment. TDT is a serious, life-threatening condition that is typically treated through frequent blood transfusions and iron chelation therapy throughout a person’s life. While stem cell transplant from a matched donor can cure the disorder, it is not accessible to many people due to a lack of available donors.

Many people living with TDT experience fatigue and shortness of breath due to anemia, and complications also include an enlarged spleen, liver and/or heart, misshapen bones, and delayed puberty. The disorder requires lifelong treatment and ultimately results in shortened life expectancy and decreased quality of life.

In the U.S., the median age of death for patients living with TDT is just 37 years-old, and the lifetime healthcare costs of managing TDT in the U.S. are estimated between $5 and $5.7 million.

Each Casgevy treatment is made specifically for individual patients using their own edited blood stem cells, and it works to increase the production of a special type of hemoglobin called hemoglobin F (fetal hemoglobin or HbF). Having more HbF, according to the company, increases overall hemoglobin levels and has been shown to improve the production and function of red blood cells. This can eliminate the need for regular blood transfusions in people with TDT.

Administering the new treatment requires stem cell transplantation experience, and Vortex said it is working with experienced hospitals to establish a network of independently operated, authorized treatment centers throughout the U.S. to offer the therapy.

Nine treatment centers are currently able to offer the treatment to eligible patients with TDT and sickle cell disease (SCD) across the U.S., and Vortex said additional centers will be activated in the coming weeks.

While Vertex has not yet announced the cost of the treatment, some estimate it could come with a hefty price tag of $2 million.

“On the heels of the historic FDA approval of CASGEVY for sickle cell disease, it is exciting to now secure approval for TDT well ahead of the PDUFA date,” said Reshma Kewalramani, M.D., the chief executive officer and president of Vertex, in a news release. “

“TDT patients deserve new, potentially curative treatment options, and we look forward to bringing CASGEVY to eligible patients who are waiting.”


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