BioNTech–Genentech Halt Personalized Cancer Vaccine Trial After Survival Imbalance

BioNTech and Genentech have terminated a Phase 2 trial of autogene cevumeran (BNT122), a personalized mRNA cancer vaccine, in patients with surgically removed, high-risk stage II or III colorectal cancer.

An independent Data Safety Monitoring Board found a numerical imbalance in overall survival between the vaccine and control groups and concluded that continuing the study was unlikely to demonstrate benefit.

Genentech confirmed that more deaths occurred in the vaccine arm in this specific patient population. However, the companies have not publicly disclosed the number of deaths in each group, so the size and statistical significance of the difference remain unclear.

The monitoring board reported no new safety signal specifically linked to autogene cevumeran. The decision was based on the unfavorable survival imbalance and lack of expected efficacy, rather than a formally established cause of death.

The halted study tested the vaccine as an adjuvant monotherapy after surgery and chemotherapy in patients who still had detectable circulating tumor DNA. A separate Phase 2 pancreatic-cancer study testing the vaccine alongside checkpoint inhibition and chemotherapy is continuing.

The news pressured BioNTech shares, which fell roughly 7%–9% in reports, and represents a setback for personalized mRNA cancer vaccines—particularly the strategy of using the vaccine alone.