Shares of BioNTech fell about 8% on Friday after the biotechnology company and its partner Genentech announced the termination of a Phase 2 clinical study evaluating their mRNA-based cancer vaccine for colorectal cancer.

Before the announcement, the stock was trading near $104.

The trial was testing autogene cevumeran as an adjunctive treatment for patients with high-risk Stage II or Stage III colorectal cancer who had already undergone surgery. An independent data safety monitoring committee found differences in overall survival between the treatment groups. The committee concluded that continuing the study would be futile, with little chance of changing the final outcome.

The study had already met its futility threshold in October 2025, but at that time the monitoring committee said the data were not mature enough to draw firm conclusions about effectiveness.

This is the second setback this year for autogene cevumeran. In March, BioNTech and Genentech ended a bladder cancer study involving the same vaccine, citing changes in the treatment standard for that indication.

Contrasting developments in mRNA oncology

The timing of Friday’s announcement was especially notable. Just one week earlier, BioNTech shares had posted their strongest trading day in six years after Moderna and Merck reported positive Phase 3 results for their mRNA melanoma vaccine given alongside Keytruda.

That news sent Moderna shares up about 177% and lifted sentiment across the mRNA sector. Friday’s decline highlighted how quickly investor expectations can shift when clinical results diverge across programs, even within the same therapeutic class.

The difference may be tied in part to tumor biology. Melanoma is considered an immunologically “hot” cancer with a high mutation burden, which generally makes it more responsive to immune-based therapies. Colorectal cancer, by contrast, is often described as “cold” and has historically been more resistant to immunotherapy.

The trial designs also differed. Moderna’s study paired its vaccine with Keytruda, a checkpoint inhibitor already used in cancer treatment. BioNTech evaluated autogene cevumeran as a monotherapy, which placed a much stricter burden on the vaccine to show efficacy on its own.

BioNTech’s next steps

BioNTech Chief Medical Officer Prof. Özlem Türeci said the results were disappointing, but noted that the study still provided scientific insights into immune-suppressive tumor resistance mechanisms. She said those findings would help guide the development of future mRNA-based cancer therapies.

Despite the setback, BioNTech continues to hold a strong financial position. The company reported €16.6 billion in cash and marketable securities in Q2 2026, even as it posted a quarterly net loss of €820.8 million.

One program remains active: BioNTech’s Phase 2 pancreatic cancer trial, which is testing autogene cevumeran alongside checkpoint inhibition therapy and chemotherapy, is continuing as planned.

Investors are now looking ahead to the ESMO Congress in October 2026, where comparative data from BioNTech and Moderna programs may be presented. BioNTech is also expecting interim data from its BNT113 study in head and neck cancer. Those cancers are generally considered more responsive to immunotherapy, which could make the upcoming readouts an important test of whether the company can translate early scientific promise into clearer clinical progress.

Roche, Genentech’s parent company, saw its U.S.-traded shares fall about 1.2% on Friday after the announcement.