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# Positive Data on New Breast Cancer Drug
- URL: https://www.fdaweb.com/positive-data-on-new-breast-cancer-drug/
- Published: 2025-09-05T12:00:00.000Z
- Updated: 2026-09-14T15:21:00.000Z
- Author: David McFarland
- Tags: Drugs, #legacy-id-D5159819

BioNTech and Duality Biologics say their experimental antibody-drug conjugate, trastuzumab pamirtecan (BNT323/DB-1303), met its primary endpoint in a pivotal Phase 3 trial for patients with HER2-positive metastatic or unresectable breast cancer. The China-based study compared trastuzumab pamirtecan to the approved therapy trastuzumab emtansine (T-DM1) in patients previously treated with trastuzumab and taxane chemotherapy. They say an interim analysis showed the candidate extended progression-free survival, leading the trial’s independent data monitoring committee to confirm success on the trial’s main endpoint.

The therapy, developed using DualityBio’s DITAC platform, is a third-generation HER2-targeted ADC linked to a topoisomerase-1 inhibitor payload, according to the companies. Early data suggested activity across both HER2-positive and HER2-low cancers, as well as other solid tumors such as endometrial cancer, they say, adding that the development program has previously received fast track and breakthrough therapy designations from FDA.