A phase 2/3 clinical trial of BioNTech’s mRNA cancer immunotherapy BNT113 has missed one of its dual primary endpoints. However, immature overall survival (OS) data are providing a glimmer of hope, and the German biotech is continuing to follow patients in the metastatic head and neck cancer study.
Market Expectations Hit a Setback
The excitement for BioNTech’s mRNA cancer therapeutic pipeline surged in August, following phase 3 results from Moderna and Merck & Co. that rejuvenated expectations for the entire therapeutic area. But having seen its share price rise 20% on the strength of external data, BioNTech came back to earth with a bump on Tuesday after it failed to replicate its rivals’ success.
In an open-label study of the efficacy of BNT113 in combination with Keytruda, called the Ahead-Merit study, BioNTech shared data from the phase 3 portion of the trial, which showed that the combination of BNT113 and Keytruda was more effective than Keytruda alone in treating metastatic melanoma. Patients with head and neck squamous cell carcinoma (HNSCC) were included in the study if they tested positive for HPV16.
PFS Endpoint Missed, but OS Assessment Moves Forward
On the BNT113 regimen, the rate of progression-free survival (PFS) was not statistically superior to single-agent Keytruda, and the study failed to meet one of its two co-primary endpoints, the Mainz, Germany-based biopharma said. The independent data monitoring committee did approve continuing the trial as planned to assess OS, the other major endpoint in the study. The statistical design translates into that an OS hit would be a positive trial outcome.
The tumor necrosis factor (TNF) may offer a possible treatment for HNSCC on paper, as it would induce an immune response against the oncogenic proteins of the HPV16 virus (E6 and E7) and strengthen existing T-cell immunity. The mechanism may be able to be used in combination with T-cell responses triggered by Keytruda. The phase 3 data show BNT113 “is engaging its intended therapeutic mechanism,” BioNTech Chief Medical Officer Özlem Türeci, M.D., said in a statement.
Türeci described the trial in the following manner: “Failure on PFS, success on OS. Tumor-killing immune responses can accumulate and intensify over time, the executive said. Meanwhile, BioNTech may demonstrate that BNT113 offers long-lasting benefits to patients with HNSCC.
Analyst Reactions and Mixed Precedents
But it’s reasonable to believe the immune response generated by BNT113 may take some time to develop, which may provide an opportunity for OS improvement, the BMO Capital Markets analysts wrote to investors. But the PFS reduced the analysts’ confidence “significantly” that BNT113 will prolong OS.
There are precedents for cancer immunotherapies that demonstrated clinical benefit in OS following failure to show PFS benefit. A phase 3 trial of Keytruda in HNSCC failed to meet its PFS endpoint, but the checkpoint inhibitor did demonstrate an OS benefit. Keytruda maintained an OS benefit over the course of five years of follow-up. But although these examples illustrate BNT113 still having a chance, numerous trials that fail to achieve PFS in the endpoints go on to fail in OS evaluations.
Stock Impact and Market Comparison
BioNTech’s stock fell 5 percent to $91.32 in pre-market trading Tuesday from a $95.84 close on Monday, and Moderna’s stock price fell 3 percent.
Both biotechs are working on mRNA cancer immunotherapies, but BNT113 is not at the level of publicity as Moderna’s high-profile intismeran autogene, which is based on a variable array of antigens. In contrast, antigens in intismeran autogene are customized based on the mutations in each patient’s tumor.
BioNTech’s mRNA Cancer Vaccine Misses a Key Trial Goal
BioNTech’s experimental mRNA cancer immunotherapy BNT113 has encountered a significant setback after failing to meet the first primary endpoint in the Phase 3 portion of its AHEAD-MERIT clinical trial. Announced on October 13, 2026, the result concerns an investigational treatment for patients with HPV16-positive head and neck squamous cell carcinoma.
BioNTech’s BNT113 is being evaluated in combination with pembrolizumab, an immunotherapy marketed as Keytruda, against pembrolizumab alone. The study aims to determine whether adding the experimental treatment can improve outcomes for patients with recurrent or metastatic disease.
The latest findings represent a setback for BioNTech’s oncology development program. However, the trial has not been declared an overall failure because researchers are continuing to assess its second primary endpoint: overall survival.
What Comes Next for BioNTech’s Cancer Vaccine?
BioNTech’s immediate priority for BNT113 is to continue evaluating overall survival in the AHEAD-MERIT trial. The remaining results will help determine whether the investigational combination provides a meaningful benefit despite the progression-free survival setback.
Until the survival analysis is complete, the treatment’s overall clinical outcome remains unresolved. The candidate is investigational and is not an established standard treatment for this cancer setting.
The results may also inform future research into antigen selection, treatment combinations, and the design of clinical studies involving mRNA-based cancer immunotherapies.
