BioNTech Launches 480-Patient ADC Trial and Adds Two Oncology Experts to Board Amid Deepening Losses

BioNTech starts Phase 3 study for ADC BNT323 in endometrial cancer, appoints two oncology veterans to supervisory board, and reports Q1 net loss of €531.9M as vaccine revenue falls.

BioNTech is sending a clear signal that its post-COVID transformation is no longer just a promise. The German biotech has kicked off a pivotal Phase 3 study for its antibody-drug conjugate trastuzumab pamirtecan (BNT323) and simultaneously reshaped its supervisory board with two oncology veterans, moves that come as first-quarter losses widen and vaccine revenue continues to slide.

The FERN-EC-01 trial, registered on May 20, is an open-label, randomized, multicenter study comparing BNT323/DB-1303 against physician’s choice chemotherapy in 480 patients with previously treated, HER2-expressing recurrent endometrial cancer. Enrollment began on June 10, 2025, with primary completion expected in March 2028 and final results by November 2029. The study spans 156 sites across the US, Argentina, and Australia. Patients are stratified by HER2 expression into two cohorts: one tracking progression-free survival following prior immune checkpoint inhibitor therapy, the other measuring objective response rate to BNT323 as a monotherapy.

The ADC, developed jointly with Duality Biologics, represents a key non-mRNA pillar for BioNTech. Management is aiming for a regulatory submission in 2026, contingent on feedback from authorities. A potentially registrational Phase 1/2 cohort in the same indication has already finished enrollment, though no new efficacy or safety data accompanied this latest disclosure.

On the corporate governance front, the annual general meeting on May 15 delivered a strong endorsement of management’s oncology strategy. With 92% of share capital represented, shareholders approved all agenda items, including expanding the supervisory board from six to eight members. Newly elected were Prof. Iris Löw-Friedrich, whose background covers clinical development and global health markets, and Dr. Susanne Schaffert, a specialist in oncology product launches. Helmut Jeggle immediately assumed the chairmanship, while the mandates of Prof. Anja Morawietz and Prof. Rudolf Staudigl were renewed.

The board refresh underscores BioNTech’s ambition to become a multi-product oncology company blending immunomodulators, ADCs, and mRNA immunotherapies. But the financial reality remains sobering. First-quarter revenue slumped to €118.1 million from €182.8 million a year earlier, driven almost entirely by collapsing COVID-19 vaccine sales. The net loss deepened to €531.9 million (or $622.3 million), reflecting stepped-up spending in oncology and ADC research. Diluted loss per share came in at €2.10.

Despite the red ink, BioNTech’s cash position offers a formidable cushion. At the end of March, the company held €16.8 billion in cash, cash equivalents, and securities. Management reiterated full-year revenue guidance of €2.0 billion to €2.3 billion. The AGM also authorized a share buyback program of up to $1 billion over the next twelve months—a move that can absorb some selling pressure, though it can’t substitute for clinical catalysts.

The stock, meanwhile, continues to trade under a cloud. Shares closed in Germany at €77.65 on Wednesday, having shed roughly 17.5% over the past month. They remain about 10% below their 200-day moving average, and the year-to-date performance is negative. A modest intraday gain of around 3% to €78 on the AGM day looked more like a technical bounce than a trend reversal.

With the FERN-EC-01 trial not expected to reach primary completion until March 2028, near-term attention will focus on whether BioNTech can deliver the planned 2026 filing for trastuzumab pamirtecan and keep its oncology pipeline marching toward registration. The board shake-up may strengthen oversight, but it is hard data from late-stage studies that will ultimately write the next chapter for this stock.