BNTX · BioNTech SE

BioNTech's trastuzumab pamirtecan (BNT323/DB-1303), developed with DualityBio, demonstrated clinically meaningful efficacy in a Phase 2 cohort of 145 heavily pre-treated patients with HER2-expressing advanced endometrial cancer. The trial met its primary endpoint of confirmed ORR in patients with prior checkpoint inhibitor therapy and central HER2 confirmation, achieving 49.3% (95% CI: 37.4-61.3). Across all 96 centrally tested patients, ORR was 47.9% (95% CI: 37.6-58.4) with mPFS of 8.1 months (95% CI: 5.5-11.8), and activity was consistent across IHC1+, IHC2+, and IHC3+ expression levels, including 33.9% ORR in IHC1+ by local testing. mDoR reached 10.3 months, and mPFS was 8.0 months overall. Safety was manageable for a HER2-ADC, with common low-grade TRAEs like nausea and anemia; Grade ≥3 TRAEs in 46.9%, and low 4.8% incidence of severe ILD/pneumonitis, aligning with class expectations. These results from the largest HER2-ADC trial in endometrial cancer highlight potential in real-world populations with lower HER2 expression and prior immunotherapy, addressing high unmet need where standard chemotherapy yields only 15% response. The FDA granted Fast Track and Breakthrough Therapy designations in 2023. A confirmatory Phase 3 trial (Fern-EC-01, NCT06340568) is enrolling versus chemotherapy, supporting planned 2026 BLA submission pending FDA feedback. Additional Phase 3 DYNASTY-Breast02 in HR+/HER2-low breast cancer is fully enrolled with readout expected this year. Chief Medical Officer Özlem Türeci emphasized advancing the asset in HER2-driven tumors, including combinations, underscoring pipeline momentum for BioNTech's ADC portfolio.