The U.S. Food and Drug Administration made a landmark decision on Friday by greenlighting the first-ever treatment in the nation that employs the revolutionary Crispr gene-editing technology.
The newly approved therapy, named Casgevy, harnesses Crispr to combat sickle cell disease, a hereditary blood disorder caused by a genetic mutation. This mutation alters the protein in red blood cells that carries oxygen throughout the body, leading these cells to assume a “sickle” shape. This abnormal shape can trigger blood clots, oxygen deficiency, and various other complications. Nicole Verdun, the director of the Office of Therapeutic Products at the FDA’s Center for Biologics Evaluation and Research, expressed enthusiasm about the approval. She highlighted the significant unmet needs in treating sickle cell disease, a rare and potentially life-threatening condition, and the approval of two cell-based gene therapies, including Casgevy.
Verdun emphasized the potential of gene therapy to offer more precise and effective treatments, particularly for rare diseases with limited existing treatment options.
Sickle cell disease predominantly affects African Americans, though it is also found in Hispanic populations. The disease impacts the production of adult hemoglobin protein, causing the distinctive sickle shape of the blood cells. Humans have two genetic blueprints for hemoglobin production – one for fetal hemoglobin and one for adult hemoglobin. After birth, the body typically switches from producing fetal hemoglobin to adult hemoglobin.
Casgevy, the Crispr-based treatment for sickle cell disease, edits the genes responsible for fetal hemoglobin production, reactivating its production. This approach represents a major advancement in medical technology, as noted by Lewis Hsu, the chief medical officer of the Sickle Cell Disease Association of America, in a conversation with CNN. Hsu described the anticipation for such a breakthrough since the discovery of DNA.
In clinical trials, Casgevy demonstrated about a 90% effectiveness in preventing severe pain and organ damage associated with sickle cell disease for at least a year. Out of 44 patients treated with Casgevy, 29 out of 31 patients with sufficient follow-up showed positive outcomes. All treated patients experienced successful engraftment without any cases of graft failure or rejection, according to the FDA.
While the pricing for Casgevy is yet to be determined, preliminary estimates suggest it could be in the millions. The Institute for Clinical and Economic Review, advising insurers and pharmaceutical companies on therapy pricing, proposed a fair price range between $1.35 million and $2.05 million per patient, as reported by The Wall Street Journal. Additionally, the FDA also approved another cell-based gene therapy for sickle cell, named Lyfgenia, which modifies a patient’s cells to produce a substitute for the defective hemoglobin protein.