BioNTech's Oncology Pivot Gets Real
For three years, BioNTech has been trying to convince investors it is more than a vaccine company that had a very good pandemic. Monday's Phase 2 readout in endometrial cancer is the strongest evidence yet that the pivot is working.
Trastuzumab pamirtecan, the HER2-targeted antibody-drug conjugate the company is developing with China's DualityBio, hit its primary endpoint in a cohort of 145 patients with recurrent endometrial cancer whose disease had progressed after at least one line of chemotherapy. The confirmed objective response rate came in at 49.3% in patients who had also received prior checkpoint inhibitor therapy, and 47.9% across all centrally HER2-tested patients. Median progression-free survival was 8.1 months. The data were presented at the Society of Gynecologic Oncology annual meeting in San Juan, Puerto Rico.
These numbers matter because the population treated was genuinely hard-to-help. Every patient had already failed chemotherapy. Most had also failed a checkpoint inhibitor. The standard-of-care chemotherapy in this setting delivers a 15% response rate. Trastuzumab pamirtecan nearly tripled that, even in patients with lower levels of HER2 expression (IHC1+ and IHC2+), where response rates were 33.9% and 40.4% respectively. In the highest HER2 expressers (IHC3+), the confirmed ORR hit 73.1%.
"Endometrial cancer is one of the few cancers with an increasing mortality rate, and there are very few options for patients with recurrent disease," said Dr. Bhavana Pothuri of NYU Langone, who presented the data.
The safety profile was manageable: nausea, anemia, and fatigue were the most common low-grade adverse events. Grade 3 or higher treatment-related events occurred in 46.9% of patients, and adjudicated cases of interstitial lung disease or pneumonitis of grade 3 or higher showed up in 4.8% of patients — consistent with the known class effect for HER2-targeted ADCs and generally manageable.
The competitive picture centers on Daiichi Sankyo and AstraZeneca's Enhertu, which is approved in HER2-expressing endometrial cancer and has set a high bar. BioNTech is not claiming superiority; the data support a differentiation story around lower HER2 expression levels and the heavily pre-treated real-world population, rather than competing head-to-head in earlier lines. The Phase 3 confirmatory trial, Fern-EC-01, is now enrolling and comparing trastuzumab pamirtecan monotherapy against investigator's choice of chemotherapy. BioNTech and DualityBio are planning to file a biologics license application in 2026, pending FDA feedback.
BioNTech co-founder and CMO Prof. Özlem Türeci called the results "a significant step forward" and noted the company is advancing the ADC both as a monotherapy and in novel combination approaches. The company has also fully enrolled DYNASTY-Breast02, a Phase 3 trial in HR+/HER2-low metastatic breast cancer, with a data readout expected this year.
The broader BioNTech story is one of strategic urgency. COVID vaccine revenues are declining sharply, and the company has guided that its oncology pipeline will not generate commercial revenue in 2026. CEO Ugur Sahin has staked the company's next decade on oncology, targeting ten cancer indication approvals by 2030 starting with launches from 2026 onward. Multiple late-stage readouts are expected this year, making 2026 a pivotal test of whether the pivot can deliver.
Trastuzumab pamirtecan's data are the first major readout of that stack. A 49% response rate in a population with a 15% chemo response rate, in a cancer with rising mortality, is a meaningful signal — not a home run, but enough to keep the pipeline story alive. The BLA filing planned for this year will be the real inflection point.
