Bristol Myers Squibb and Novartis delayed public disclosure of serious safety developments in CAR-T trials for autoimmune diseases. Bristol Myers halted enrollment in its zola-cel study in June after cases of immune effector cell-associated neurotoxicity syndrome, or ICANS, but waited three months to announce the pause publicly after notifying federal regulators. Novartis suspended trials of competing therapy rap-cel after three patients died from a rare immune reaction, confirming the deaths only after William Blair analyst scrutiny of database changes and subsequent reporting by Endpoints News. Both therapies modify patients' immune cells to treat conditions including lupus and rheumatoid arthritis, while their different manufacturing processes have raised questions about toxicity. Federal rules require rapid safety reporting to regulators but generally do not mandate public disclosure unless a trial materially affects a company's bottom line. Novartis shares were down 1.58% at $160.52 and Bristol Myers shares fell 1.73% to $66.91 on Friday at publication.