The U.S. Food and Drug Administration (FDA) has granted approval for two groundbreaking gene therapies targeting sickle cell disease, marking a significant achievement in the field of CRISPR gene editing technology.
Casgevy, developed collaboratively by Vertex Pharmaceuticals and CRISPR Therapeutics, and Bluebird Bio’s Lyfgenia have both been approved for individuals aged 12 and older.
Casgevy, which is based on CRISPR gene editing technology, carries a U.S. list price of $2.2 million, while Bluebird’s Lyfgenia is priced at $3.1 million. Both therapies, positioned as one-time treatments, are scheduled to be available in early 2024.
However, Bluebird’s higher pricing and associated safety warnings are expected to have an impact on its sales compared to Casgevy. Market reactions were apparent, with Bluebird’s shares plummeting by 40%, CRISPR Therapeutics down by 8%, and Vertex falling by 0.5%.
Casgevy utilizes CRISPR, a revolutionary technology pioneered by Jennifer Doudna and CRISPR Therapeutics co-founder Emmanuelle Charpentier. The CRISPR technology acts as molecular “scissors,” trimming faulty gene parts that can be replaced with new strands of normal DNA. In contrast, Bluebird’s gene therapy involves inserting modified genes into the body through disabled viruses.
The FDA’s approval follows thorough evaluations of scientific and clinical data, emphasizing the commitment to facilitating the development of safe and effective treatments for severe health conditions, according to FDA official Peter Marks.
Both therapies demonstrated effectiveness in reducing painful episodes during separate clinical trials. Casgevy showed improvement in 29 of 31 patients, while 28 of 32 patients on Lyfgenia exhibited positive outcomes.
While Vertex’s CRISPR therapy is also under FDA review for another blood disease, transfusion-dependent beta-thalassemia, with a decision expected by March 30, the FDA has added a warning to Lyfgenia’s label regarding the risk of blood cancer.
Ongoing monitoring and a 15-year follow-up study will assess potential long-term safety risks for patients treated with these gene therapies.
Sickle cell disease is an inherited blood disorder characterized by flawed, sickle-shaped hemoglobin, hindering the proper transport of oxygen by red blood cells. With an estimated 100,000 affected individuals in the U.S., predominantly from the Black community, the disease causes pain and can lead to premature death.
Nigeria has the largest population of persons affected with sickle cell disease globally. 90% of the world’s sickle cell disease population lives in Nigeria, India, and the Democratic Republic of Congo.
According to the WHO, the majority of children in the African Region with the most severe form of the disease die before the age of five, usually from an infection or severe blood loss.
