Novartis Pauses CAR-T Autoimmune Trials After Three Patient Deaths; Bristol Myers Follows

Novartis (NYSE: NVS) temporarily halted eight clinical trials of rap-cel, its experimental CAR-T cell therapy for autoimmune and neurological disorders, after three patients died from a severe immune response, The Wall Street Journal reported on September 1. Bristol Myers Squibb (NYSE: BMY) paused its own CAR-T trials in autoimmune disease as a precaution, the same report said. NVS closed at $152.06 on August 31, down 1.1% from Friday’s $153.81; BMY closed at $66.81, up 0.3%. The news broke before Tuesday’s open, so the first full market reaction is still ahead.

rap-cel engineers a patient’s own T cells to attack a specific target, and Novartis is testing it in lupus, multiple sclerosis, and other autoimmune and neurological conditions. The three deaths stemmed from a severe immune reaction, a recognized CAR-T risk most often tied to cytokine release syndrome or immune effector cell-associated neurotoxicity. Novartis has not said when the patients died or specified the mechanism. The company told the Journal it is running “a comprehensive review of the observed safety events,” working with the independent safety boards that oversee each paused study and sharing what it knows with regulators.

Why It Matters

CAR-T’s move from oncology into autoimmune disease is one of biotech’s biggest bets. Novartis, Bristol Myers, Kyverna, Cabaletta, and others are racing to prove the technology can reset the immune system in lupus, MS, and other chronic conditions. Novartis itself launched the first approved CAR-T, Kymriah, back in 2017 for blood cancer. But autoimmune patients are generally healthier than the end-stage cancer patients CAR-T was originally built for, which raises the bar: three deaths from a severe immune reaction land differently when baseline mortality is lower. This is the most significant safety signal yet for CAR-T in autoimmune disease and could slow the entire field’s expansion into chronic indications. For how the platform works, see our CAR-T explainer.

What Happens Next

The read-through is sharpest for pure-play CAR-T autoimmune developers. Cabaletta (Nasdaq: CABA) closed at $3.11 on August 31; Kyverna and others run similar programs in lupus. Three things to watch: details on which trials and doses the deaths occurred in, whether the FDA imposes a broader hold beyond the company-initiated pause, and whether other sponsors follow Bristol Myers’ lead. Novartis’s review will set the tone for how the whole field proceeds. We covered the investor setup in our CAR-T stocks piece.