BioNTech cancer vaccine trial halted after survival imbalance
BioNTech and Genentech have terminated a Phase 2 trial of their personalized mRNA cancer vaccine autogene cevumeran in colorectal cancer after more deaths occurred in the vaccine arm than among patients under observation. The setback comes just days after rival Moderna scored the first Phase 3 success for an individualized mRNA cancer therapy — albeit in combination with a checkpoint inhibitor.
Why it matters: The contrasting results sharpen an emerging lesson for personalized cancer vaccines: stimulating tumor-specific T cells may not be enough on its own, particularly against tumors that are poorly responsive to immunotherapy.
What happened: BioNTech and Roche subsidiary Genentech stopped the BNT122-01 trial after its independent Data Safety Monitoring Board found a numerical imbalance in overall survival and concluded that continuing the study was unlikely to change its efficacy outcome. Genentech confirmed to Fierce Biotech that there had been more deaths in the vaccine arm in this patient population.
Zoom in: The trial was testing autogene cevumeran, also known as BNT122 or RO7198457, as a standalone adjuvant treatment in patients with ctDNA-positive, surgically removed Stage II high-risk or Stage III colorectal cancer. The approximately 200-patient study compared the personalized vaccine with watchful waiting, aiming to see whether the treatment could prevent the cancer from returning after surgery and chemotherapy.
Yes, but: The trial already crossed a predefined futility boundary in October 2025, but the monitoring board considered the data too immature at the time to draw reliable efficacy conclusions. BioNTech continued the study in the absence of safety concerns.
How it works: Autogene cevumeran is made individually for each patient. Tumor sequencing identifies cancer-specific mutations, or neoantigens, which are encoded into an mRNA vaccine intended to teach the immune system’s T cells to recognize the patient’s tumor.
Backstory: The program dates back to BioNTech and Genentech’s 2016 collaboration on individualized mRNA cancer therapies. Genentech committed $310 million in upfront and near-term milestone payments, with the partners agreeing to share development costs and potential profits.
Reality check: Colorectal cancer is generally considered an immunologically “cold” tumor, meaning the immune system has difficulty mounting an effective response against it. BioNTech said the outcome highlights the challenge of using mRNA immunotherapy alone against tumors with immunosuppressive microenvironments. That distinction matters because much of the momentum behind personalized cancer vaccines now comes from combinations.
- Just nine days before BioNTech disclosed the termination, Moderna and Merck reported that their personalized mRNA therapy intismeran autogene combined with Keytruda met its recurrence-free and distant metastasis-free survival endpoints in a 1,137-patient Phase 3 melanoma trial — the first positive Phase 3 result for an individualized neoantigen therapy.
What’s next: BioNTech is not abandoning autogene cevumeran. Its randomized Phase 2 IMcode003 trial in resected pancreatic cancer continues, combining the vaccine with checkpoint inhibition and chemotherapy.
- Earlier Phase 1 research in pancreatic cancer found vaccine-induced T-cell responses in eight of 16 treated patients, providing the rationale for moving into the larger study.
Bottom line: The colorectal failure therefore looks less like a verdict on personalized mRNA cancer vaccines than a setback for using them alone. For BioNTech, the next test is whether combinations can unlock the immune response that the vaccine could not generate by itself.
