NEW YORK – The US Food and Drug Administration on Tuesday approved a second indication for Vertex Pharmaceuticals' CRISPR gene-editing therapy Casgevy (exagamglogene autotemcel) in transfusion-dependent beta thalassemia (TDT).
The FDA approved Casgevy, developed by Boston-based Vertex and Zug, Switzerland-based CRISPR Therapeutics, as a sickle cell disease treatment in December. The drug also received conditional marketing authorization from the UK Medicines and Healthcare Products Regulatory Agency (MHRA) in these two disease settings in November.
The FDA was not expected to issue a decision on Casgevy's TDT indication until March 30. "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 [Prescription Drug User Fee Act] date," Vertex President and CEO Reshma Kewalramani said in a statement.
The FDA has approved Casgevy as a one-time and potentially curative treatment for patients at least 12 years old with TDT, a genetic blood disorder in which patients do not produce enough hemoglobin, the protein that carries oxygen throughout the body. Casgevy addresses this issue through ex vivo editing of the BCL11A gene in patients' own CD34-positive hematopoietic stem and progenitor cells with CRISPR-Cas9. The edited genes are designed to increase production of fetal hemoglobin, which, like the adult version, facilitates oxygen delivery.
Vertex previously said it submitted interim data from pivotal trials to the FDA as part of its applications for Casgevy in sickle cell and TDT, demonstrating that 24 out of 27 patients who received the gene-editing therapy for TDT achieved transfusion independence for at least 12 months after treatment. Last month, Vertex presented updated findings at the American Society of Hematology's annual meeting showing that 32 of 35 patients in an ongoing pivotal Phase III trial with at least 16 months of follow-up had achieved transfusion independence after receiving Casgevy.
When announcing the approval of Casgevy for sickle cell in December, Vertex said it had set a wholesale acquisition cost of $2.2 million for the gene-editing therapy in the US.