BioNTech

Trastuzumab pamirtecan (BNT323/DB-1303)

In Development

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.

Latest update Oct 29, 2026

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Current status

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; additional ESMO Gynaecological Cancers Congress 2026 data (June 2026) confirmed durable activity and a manageable safety profile, and the registrational endometrial-cancer cohort is now fully recruited. A separate pivotal Phase 3 trial (DB-1303-O-3001) in HER2-positive metastatic/unresectable breast cancer met its primary endpoint of progression-free survival versus trastuzumab emtansine (T-DM1); on that data, partner DualityBio's China BLA for the breast-cancer indication was accepted for review by the NMPA on April 9, 2026 - the first regulatory filing acceptance anywhere for the asset. The endometrial-cancer indication has not yet been filed anywhere; BioNTech and DualityBio are still determining the optimal US regulatory path across both indications, with a US BLA filing still planned for 2026. On Oct. 26, 2026 a different Phase 3, DYNASTY-Breast02 in chemotherapy-naive HR-positive HER2-low metastatic breast cancer, met PFS with a statistically significant but modest improvement. The release gives no median, hazard ratio, confidence interval, or event count, says overall survival is immature, and says the companies will discuss next steps. They did not name a new trial or filing for that setting.

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Specifications3

Endometrial Cancer ORR
47.9% (>70% in IHC 3+ patients)
Breast Cancer Phase 3
Met primary endpoint

(PFS) in HER2+ mBC vs. T-DM1

China BLA Status

Breast-cancer indication accepted for review by NMPA (Apr 9, 2026); endometrial not yet filed

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