The Food and Drug Administration is requiring companies that make specialized cancer therapies known as CAR-T to add a boxed warning that the treatments themselves may cause cancers.
The agency noted that the benefits still outweighed the risks of the therapy, which involves removing a type of white blood cells — T cells — and then genetically engineering them to create proteins called chimeric antigen receptors (CAR). Infused back into a patient’s blood, the engineered cells allow the T cells to attach to cancer cells and kill them.
But the therapies, which mostly treat blood cancers, including multiple myeloma, had already carried a warning for dangerous immune responses and for neurological risks. And the new warning follows reports of about 25 cases of secondary cancers that federal health officials and others have suspected were caused by CAR-T treatments, although more investigation may be needed to establish a definite link. The therapy has been used by at least 27,000 patients since it was first approved by the F.D.A. in 2017, the agency has said.
Cancer patients who receive CAR-T treatments tend to have few options left, and would be unlikely to alter course even with the new warning, said Dr. John DiPersio, an oncologist with Washington University in St. Louis.
