FDA Expands Approval of CASGEVY for Beta Thalassemia

On January 16, 2024, Vertex Pharmaceuticals and CRISPR Therapeutics secured yet another approval for CASGEVY, the first FDA-approved gene therapy in the United States. Last month, the companies’ collaboration on CASGEVY (exagamglogene autotemcel [exa-cel]) was approved for patients 12 and older with sickle cell disease who have vaso-occlusive crises. 

CASGEVY is a RISPR/Cas9 genome-editing technology that alters the erythroid-specific enhancer region of the BCL11A gene in CD34+ hematopoietic stem cells (HSCs), triggering an increased production of hemoglobin.

Adding to its approved indications, the FDA approved the companies to use CASGEVY for patients 12 and older with transfusion-dependent beta thalassemia (TDT).

“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, MD, Chief Executive Officer and President of Vertex, in the press release. “TDT patients deserve new, potentially curative treatment options, and we look forward to bringing CASGEVY to eligible patients who are waiting.”

Beta thalassemia is a genetic blood disorder that reduces hemoglobin production and is characterized by various symptoms, including pale skin, poor appetite, recurrent infections, slowed growth, jaundice, fatigue, and weak bones.

According to the press release, TDT is a type of beta thalassemia that requires patients to undergo frequent blood transfusions and iron chelation therapies. As a result, patients have reduced quality of life scores and contribute to up to $5.7 million in healthcare spending in the US annually.

Beyond the symptoms and costs associated with thalassemia, transfusion dependence may reduce life expectancy and contribute to other complications.

However, with a gene therapy like CASGEVY that increases hemoglobin production through gene editing, TDT's side effects and costs can be minimized.

Despite the potential benefits, the company acknowledges some possible side effects of the treatment, including low platelets, low white blood cell count, fever, chills, infections, headaches, prolonged bleeding, and abnormal bruising.

“We are pleased with the approval of CASGEVY in TDT well ahead of the PDUFA date,” said Samarth Kulkarni, PhD, Chairman and Chief Executive Officer of CRISPR Therapeutics, added in the organization’s statement. “The approval is a reflection of the power and versatility of the CRISPR platform to bring a potentially curative treatment option to patients suffering from this devastating disease.”