Merck and Moderna vaccine data leak ahead of ESMO, Merck's sac-TMT cuts endometrial cancer deaths, BMS reports CAR-T death

A data leak of the highly anticipated personalized cancer vaccine being developed by Merck and Moderna surfaced online before the European Society for Medical Oncology (ESMO) meeting. The premature disclosure initially disappointed investors, but the companies later presented the full data at the conference, which helped restore confidence.

At the same conference, Merck disclosed results for its TROP2‑directed antibody‑drug conjugate sac‑TMT, developed with Kelun‑Biotech. The trial in advanced endometrial cancer showed a more than 30% reduction in the risk of death compared with standard therapy, marking a notable efficacy signal.

Bristol Myers Squibb (BMS) also used the forum to report a serious safety event: a patient with multiple sclerosis died during an early‑stage trial of the CAR‑T therapy zola‑cel. The company highlighted the incident as an isolated autoimmune complication.