Following an investigation announced in November last year, the FDA said on Thursday that it would now require boxed warnings—the highest safety-related caution for medications—for all chimeric antigen receptor (CAR) T-cell therapies.

According to the agency, these blood cancer treatments may pose a risk of secondary cancers.

The health regulator has required related updates to other label sections, such as warnings and precautions, postmarketing experience, patient counseling information, and medication guides.

The agency said patients and clinical trial participants receiving treatment with these products should be monitored lifelong for secondary malignancies and notify the manufacturer in the event of a new malignancy.

In November, the FDA said it received reports of patients developing T-cell malignancies, including chimeric antigen receptor CAR-positive lymphoma, in patients who received treatment with BCMA- or CD19-directed autologous CAR T cell immunotherapies.

The agency said it's weighing "the need for regulatory action" in response to clinical testing and safety monitoring reports tied to commercial use.

In January, the FDA asked drugmakers to add a boxed warning to their CAR-T cancer therapies.

In its January 19 notification letters, the agency stressed that the potential risk applies to all currently approved CAR-T products.

The regulatory body has mandated label updates for all six commercial CAR-T therapies, including Bristol Myers Squibb & Co's (NYSE:BMY) Abecma (partnered with partner 2seventy bio Inc (NASDAQ: TSVT))and Breyanzi, Johnson & Johnson's (NYSE:JNJ) Carvykti (developed in partnership with Legend Biotech Corporation (NASDAQ: LEGN)), Novartis AG's (NYSE:NVS) Kymriah, and Gilead Sciences Inc's (NASDAQ:GILD) Yescarta.

Gilead's Tecartus was also part of the list, but later, it was removed from boxed warning requirements.

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