Trastuzumab pamirtecan (BNT323/DB-1303)
Overview
A HER2-targeted antibody-drug conjugate (third-generation topoisomerase-1 inhibitor payload) co-developed with China's DualityBio - BioNTech's lead candidate for its first-ever cancer-drug regulatory submission, being tested in HER2-expressing endometrial cancer and HER2-positive breast cancer.
Phase 2 data (cutoff October 17, 2025) showed a 47.9% objective response rate in HER2-expressing advanced/recurrent endometrial cancer (exceeding 70% in IHC 3+ patients), with 8.0-month median progression-free survival and 15.0-month median overall survival. A separate Phase 3 trial in HER2-positive metastatic/unresectable breast cancer met its primary endpoint of progression-free survival. BioNTech and DualityBio plan a first US BLA filing (endometrial cancer) in 2026, subject to FDA feedback.