FDA Issues Warning of Cancer Risk Tied to CAR-T Therapies

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.

“The risk of not doing this therapy for most patients who get it is rapid progression of their disease or certain death,” he said.

The F.D.A. raised concerns about the adverse effects of the treatments late last year.

In letters dated Jan. 19, the agency outlined the warnings to be included by some of the companies making CAR-T therapies, which had also been ordered to monitor patients for secondary cancers and report any to the F.D.A. The secondary cancers can lead to hospitalizations or death, the agency noted, requiring the drug companies to provide warnings on drug labels that secondary cancers “may present as soon as weeks following infusion, and may include fatal outcomes.”