Novartis and Bristol Myers pause CAR-T studies after fatal immune reactions

Novartis has halted trials of its CD19-directed CAR-T therapy after three patient deaths linked to a severe immune response. Bristol Myers Squibb has also paused a similar program to review safety concerns. The pauses highlight ongoing challenges in managing toxicity from engineered cell therapies.

The clinical holds follow three fatalities attributed to a severe immune reaction in patients receiving Novartis's CD19-directed CAR-T product. Bristol Myers Squibb has also paused its investigational program while investigators examine whether comparable safety signals exist. Both companies are reviewing their respective protocols and patient monitoring procedures.

These pauses underscore a persistent tension in engineered cell therapy: such treatments can be highly effective against blood cancers, yet their potency carries risk of dangerous inflammatory responses. The events serve as a reminder that even well-established targets like CD19 require careful toxicity management as developers push toward broader clinical use.