BioNTech stock fell about 8% on Friday after the company and Genentech terminated a Phase 2 clinical trial of their mRNA cancer vaccine in colorectal cancer. The shares were trading around $104 before the announcement.

The trial was evaluating autogene cevumeran as an add-on treatment for patients with high-risk Stage II or Stage III colorectal cancer after surgery. Autogene cevumeran, developed under the code BNT122, is an individualized neoantigen therapy — a vaccine tailored to the unique mutation profile of each patient’s tumor — and it is the centerpiece of a cancer-vaccine collaboration between BioNTech and Genentech that dates to 2016. The vaccine was being tested on top of standard post-surgery care, which for high-risk Stage II and Stage III disease typically involves chemotherapy.

An independent data safety monitoring board found an imbalance in overall survival between the two treatment arms. The board concluded that continuing the study would be futile and unlikely to change the outcome.

The trial had already crossed its futility boundary in October 2025. At that time, however, the board said the data was not mature enough to draw firm conclusions about efficacy.

This is the second setback for autogene cevumeran in 2026. In March, BioNTech and Genentech halted a bladder cancer trial of the same vaccine, citing changes in the standard-of-care landscape.

A contrast with last week’s mRNA rally

The timing was stark. Just last week, BioNTech stock rose to its best session in six years after Moderna and Merck reported a successful Phase 3 trial for their mRNA melanoma vaccine combined with Keytruda.

That result sent Moderna shares up about 177% and lifted the broader mRNA sector. Friday’s announcement underscored that success in one cancer type does not necessarily translate to another.

The difference also reflects tumor biology. Melanoma is considered an immunologically “hot” cancer with a high mutation rate and a tendency to respond to immune-based therapies. Colorectal cancer is generally considered “cold” and has historically been more resistant to immunotherapy. The main exception is the minority of colorectal tumors that are microsatellite-instability-high, which do respond to checkpoint inhibitors such as Keytruda; most colorectal cancers are microsatellite-stable and have proven largely refractory to immune approaches.

There was also a design difference between the studies. Moderna combined its vaccine with Keytruda, a checkpoint inhibitor with established clinical activity. BioNTech tested autogene cevumeran as a standalone monotherapy, which created a much higher clinical bar.

BioNTech points to scientific lessons

BioNTech Chief Medical Officer Prof. Özlem Türeci said the results were disappointing, but added that they provided scientific insight into why immune-suppressive tumors resist treatment. She said the findings would help inform future mRNA-based cancer therapies.

Despite the setback, BioNTech’s financial position remains strong. The company reported €16.6 billion in cash and securities in Q2 2026, even as it posted a net loss of €820.8 million for the quarter. That cushion was built largely on profits from Comirnaty, the COVID-19 vaccine BioNTech developed with Pfizer, and it is now funding the company’s pivot into oncology.

One study remains active. BioNTech’s Phase 2 pancreatic cancer trial is evaluating autogene cevumeran in combination with checkpoint inhibition and chemotherapy, and it is continuing as planned. That study builds on an earlier small Phase 1 trial, published in Nature in 2023, in which about half of the 16 vaccinated patients mounted vaccine-induced T-cell responses and those responders remained recurrence-free longer at follow-up — a suggestive, though not definitive, signal that kept the program advancing.

Investors are now looking ahead to the ESMO Congress in October 2026, where data from BioNTech and Moderna could be presented side by side.

BioNTech also has an interim analysis pending for its BNT113 trial in head and neck cancer. BNT113 targets HPV16-associated disease, and that cancer type is considered more immunotherapy-sensitive, which could make it a more favorable setting for the vaccine.

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