December 12, 2023
In a groundbreaking move, the U.S. Food and Drug Administration (FDA) has granted approval for two gene-based treatments for sickle cell disease, marking a pivotal moment in the field of genetic medicine. The newly approved therapies, Casgevy and Lyfgenia, signal the advent of a new era in treating genetic conditions and bring renewed hope to the estimated 100,000 people in the U.S. suffering from sickle cell disease, particularly affecting African Americans.
Casgevy, developed by Vertex Pharmaceuticals and Crispr Therapeutics, is the first therapy utilizing the gene-editing technique CRISPR. Lyfgenia, created by bluebird bio, employs an older gene therapy approach. Both treatments have been cleared for individuals aged 12 and older with a history of vaso-occlusive crises, painful events associated with sickle cell disease.
The FDA’s approval has sparked optimism among the sickle cell community, addressing a condition long considered neglected by the pharmaceutical industry. Sickle cell disease, caused by a genetic mutation affecting red blood cells, results in misshapen cells that can cause organ damage and excruciating pain crises. Until now, the only potential cure involved a bone marrow or stem cell transplant, a solution often inaccessible due to the challenge of finding suitable donors.
Casgevy, priced at $2.2 million for a one-time treatment, and Lyfgenia, priced at $3.1 million, have raised concerns about affordability and access. The Institute for Clinical and Economic Review recommended a lower pricing range for cost-effectiveness. Discussions with insurance providers and Medicaid agencies are ongoing, but challenges related to treatment costs and the need for specialized medical infrastructure persist.
The groundbreaking CRISPR technology used in Casgevy enables precise gene editing to re-introduce fetal hemoglobin production, compensating for the defective hemoglobin causing sickle cell. Clinical trials, including that of 15-year-old Johnny Lubin, have shown promising results, with patients experiencing freedom from pain crises for extended periods.
While celebrating the transformative impact of these gene therapies, experts acknowledge the associated challenges, including the need for extensive medical care during treatment. The FDA has issued a black box warning for Lyfgenia, citing a potential risk of blood cancer, and ongoing research aims to improve the conditioning process to minimize side effects.
Despite these challenges, the approval of Casgevy and Lyfgenia represents a significant leap forward in treating sickle cell disease and offers hope for a future where cutting-edge therapies may become more accessible and sustainable for patients worldwide. The quest for continued advancements in gene therapy, including the exploration of pill-based alternatives, holds the potential to revolutionize treatment approaches for genetic disorders globally.