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  • Writer's pictureThe Rare360 Editorial Team

Milestone in Gene Therapy: Casgevy Approved for Transfusion-Dependent Beta Thalassemia

FDA APPROVED text on sticker on the blue background with two silver pens on the left side of the notepad.

The U.S. Food and Drug Administration (FDA) granted approval on January 16, 2024, for CASGEVY™ (exagamglogene autotemcel [exa-cel]), marking a significant milestone in the field of gene therapy. This CRISPR/Cas9 gene-edited cell therapy received regulatory approval for the treatment of transfusion-dependent beta-thalassemia (TDT) in patients aged 12 and above. 


The announcement comes just a month after the FDA approved Casgevy, the first CRISPR gene editing therapy in the US, in December 2023 to treat sickle cell disease. FDA’s decision to expand the use of Casgevy for the treatment of TDT was more than two months ahead of its expected action date of March 30, 2024. Casgevy is now the second FDA-approved gene therapy option for 7TDT. In August 2022, the FDA approved betibeglogene autotemcel or beti-cel as the first gene therapy for people living with TDT. The list price for this one-time treatment is $2.8 million in the United States.

About Transfusion-dependent Beta Thalassemia (TDT)

Transfusion-dependent Beta Thalassemia (TDT) is a serious life-threatening genetic disorder that disrupts the normal production of hemoglobin in the blood. This condition leads to anemia, manifesting in symptoms such as fatigue and shortness of breath among affected individuals. Infants with TDT may develop jaundice, feeding problems, and failure to thrive. 


Complications associated with TDT can also include an enlarged spleen, liver and/or heart, along with misshapen bones and delayed puberty. The management of TDT necessitates lifelong treatment, involving frequent blood transfusions (usually every two to five weeks) and iron chelation therapy, which ultimately takes a toll on life expectancy, quality of life, and lifetime earnings and productivity. In the United States, the median age of death for patients living with TDT is 37 years.


While a stem cell transplant from a matched donor offers a curative option, its availability remains limited to a small fraction of TDT patients due to the scarcity of suitable donors.


Globally, it is estimated that over 100,000 people grapple with transfusion-dependent thalassemia, with at least 1,200 individuals affected by this disorder in the United States alone.

About Casgevy

Casgevy has secured approval as the first treatment utilizing the Nobel Prize-winning CRISPR gene editing technology in the United States. Casgevy, a one-time therapy designed for individuals aged 12 years and older, addresses two critical conditions:

  • Sickle cell disease (SCD) in patients experiencing frequent vaso occlusive crises (VOCs)

  • Beta thalassemia (β-thalassemia) in individuals requiring frequent blood transfusions

Casgevy is custom-made for each patient, utilizing their own edited blood stem cells. This innovative approach enhances the production of a specialized type of hemoglobin known as hemoglobin F (fetal hemoglobin or HbF). Increased levels of HbF have demonstrated improvements in overall hemoglobin levels, enhancing the production and function of red blood cells. This breakthrough can potentially eliminate VOCs in sickle cell disease patients and eliminate the need for regular blood transfusions in individuals with beta-thalassemia. Common side effects include mouth sores, fever due to a low level of white blood cells, and decreased appetite.

As a one-time treatment, Casgevy administration requires expertise in stem cell transplantation. Consequently, the pharmaceutical company is collaborating with experienced hospitals to establish a network of independently operated, authorized treatment centers (ATCs) across the U.S to offer Casbevy to eligible patients. As of now, nine (9) ATCs have been activated, offering Casgevy to eligible patients with TDT and SCD. Approximately 1,000 patients aged 12 and older in the U.S. are now eligible for this transformative treatment.

Casgevy is expected to be made available early this year at a list price of $2.2 million in the United States for both SCD and TDT. TDT patients report health-related quality of life scores below the general population and the lifetime healthcare costs for managing TDT in the U.S. range between $5 and $5.7 million.



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