BioNTech’s mRNA Cancer Immunotherapy Misses Its First Goal in a Key Head and Neck Cancer Trial

BioNTech, the German company best known for developing the Pfizer Covid-19 vaccine, said its experimental mRNA cancer immunotherapy BNT113 failed to meet the first of two main goals in a late-stage trial in head and neck cancer. At an interim analysis, adding BNT113 to Merck’s immunotherapy Keytruda did not extend progression-free survival compared with Keytruda alone. BioNTech shares fell about 6% on the news on October 13, 2026.

What happened

The trial is testing BNT113 plus Keytruda as a first treatment for people with advanced head and neck squamous cell carcinoma caused by HPV16, a high-risk strain of the human papillomavirus. It has two primary measures of success: whether the combination delays the cancer’s growth or spread (progression-free survival), and whether patients live longer (overall survival). The first was missed. An independent data monitoring committee recommended that the trial continue to assess the second. If the combination ultimately extends survival, BioNTech could still claim success. The company did not release detailed figures.

What BNT113 is

BNT113 is an mRNA immunotherapy, sometimes loosely called a cancer vaccine. Like a Covid vaccine, it delivers genetic instructions that cells use to make specific proteins. Here, the proteins are fragments of two viral proteins, E6 and E7, that HPV16-driven tumors depend on and display. The aim is to train the immune system’s T cells to recognize and attack cells carrying those markers. Unlike a preventive vaccine, it is given to people who already have cancer.

Why HPV-driven head and neck cancer

HPV is best known for causing cervical cancer, but it also causes a growing share of cancers of the throat, particularly the tonsils and the base of the tongue. In several countries, including the US, these have become more common than cervical cancer, and they affect men more often than women. Because the tumor’s cells carry viral proteins that healthy cells lack, HPV-driven cancers looked like an ideal target for a vaccine-style therapy: the immune system has something clearly foreign to aim at.

Why the miss matters

Keytruda, a checkpoint inhibitor that releases a brake on T cells, is the standard first treatment for many patients with this cancer, but most do not respond for long. Combining it with a therapy that directs T cells to a specific target is a logical way to improve results, and BNT113 was one of the most advanced tests of that idea with mRNA. A failure to slow progression suggests the added immune response was not strong enough, or not fast enough, to change the course of the disease in most patients.

Could survival still improve?

It is possible, and not merely wishful. Immunotherapies sometimes improve overall survival without improving progression-free survival, because immune responses can take time to develop and because scans can be misleading: tumors may appear to grow at first as immune cells move in. BioNTech’s chief medical officer, Özlem Türeci, said the early results “support continued evaluation” and show the combination is engaging its intended mechanism. But a missed first endpoint lowers the odds, and investors reacted accordingly.

The skeptics saw it coming

Not everyone was surprised. Analysts at Leerink Partners wrote in August that the evidence supporting BNT113 in head and neck cancer was “sparse” and said they expected a negative result, in part because the patients enrolled had lower levels of PD-L1, a marker that predicts response to drugs like Keytruda. They also noted that BioNTech is “leaning ever more” on a different drug, the bispecific antibody pumitamig, which it is developing with Bristol Myers Squibb in multiple late-stage trials.

The Keytruda problem

BNT113 joins a long list of drugs that have failed to beat Keytruda alone when added to it. Keytruda already produces durable responses in a minority of patients, so a partner drug has to help the majority who do not respond — a much harder task. Trials are also expensive and slow, and many promising early signals from small studies have faded in large randomized ones.

What it means for mRNA cancer vaccines

The result should not be read as a verdict on the whole field. BNT113 is an off-the-shelf product aimed at fixed viral targets and tested in advanced, visible disease. The most encouraging mRNA results so far have come from a different approach: personalized vaccines built from each patient’s own tumor mutations and given after surgery, when little cancer remains, as in melanoma. Whether mRNA immunotherapies can work once a cancer has spread widely remains an open question. For BioNTech, the setback follows an earlier disappointment in colorectal cancer this year, at a time when Covid vaccine sales have fallen sharply and the company is betting its future on oncology.

What patients should know

Nothing changes in current treatment: Keytruda, with or without chemotherapy, remains a standard first option for advanced head and neck cancer, and patients already in the trial continue to be followed. The most effective tool against HPV-driven cancers is still prevention: the HPV vaccine, recommended for adolescents and available to adults in many countries, prevents the infections that cause them. This is research news, not medical advice.