The Food and Drug Administration (FDA) on Friday approved a new therapy for treating sickle cell disease, with this move also marking the first instance of CRISPR gene editing receiving approval from federal regulators.
The FDA approved two new treatments for sickle cell disease (SCD) on Friday, Casgevy and Lyfgenia.
Casgevy, also known as exa-cel, is developed through a partnership between Vertex Pharmaceuticals and CRISPR Therapeutics. The treatment involves taking a sickle cell patient’s own stem cells, editing them to create more fetal hemoglobin and transplanting them back into the individual.
When more fetal hemoglobin is produced, red blood cells don’t become “sickle” shaped, which is what causes the complications and pain associated with SCD. About 100,000 people in the U.S. have SCD, with the disease mostly affecting Black patients.
The FDA has approved the treatment for SCD patients 12 years old and up.
“Sickle cell disease is a rare, debilitating and life-threatening blood disorder with significant unmet need, and we are excited to advance the field especially for individuals whose lives have been severely disrupted by the disease by approving two cell-based gene therapies today,” Nicole Verdun, director of the FDA’s Office of Therapeutic Products, said in a statement.
A bone marrow transplant has long been the only curative treatment for SCD, with an ideal donor usually being a fully related sibling. There is, however, only a 1-in-4 chance that a sibling will be a match and most patients don’t have this option. Casgevy essentially makes a patient their own donor.
Lyfgenia is similarly a cell-based gene therapy in which stem cells are also genetically modified to produce HbAT87Q, a type of hemoglobin that also prevents red blood cells from becoming sickle-shaped.
Peter Marks, director of the FDA’s Center for Biologics Evaluation and Research, said the approval of these treatments marked an “important medical advance” to treat diseases and improve public health.
The safety and effectiveness of both Casgevy and Lyfgenia were demonstrated through months-long studies presented to the FDA. The agency said patients who receive these treatments will also be followed in a long-term study to further determine their safety and effectiveness.
“CASGEVY’s approval by the FDA is momentous: it is the first CRISPR-based gene-editing therapy to be approved in the U.S. As importantly, CASGEVY is a first-in-class treatment that offers the potential of a one-time transformative therapy for eligible patients with sickle cell disease,” Vertex CEO Reshma Kewalramani said in a statement.
Andrew Obenshain, CEO of bluebird bio, said in a statement, “Bringing LYFGENIA to people living with sickle cell disease is a milestone that bluebird has been working toward for almost a decade—and one that members of the sickle cell disease community have been waiting on for much longer.”
Though these treatments have the potential to help thousands of patients who would otherwise not have other curative options, the cost is also projected to be immense. Early estimates have placed the cost of Casgevy as being upwards of $2 million per patient.
And concerns over off-target editing and unintended genetic alterations have long followed CRISPR gene editing. While this has not been observed in any of the trials conducted by Vertex, some FDA advisers did call for more inquiries into this potential issue when reviewing Casgevy earlier this year.
