Sichuan Kelun-Biotech Publishes Phase 3 HER2-Targeted Antibody-Drug Conjugate Trastuzumab Botidotin vs T-DM1 Data in Journal of Clinical Oncology: 11.1 vs 4.4 Months Median Progression-Free Survival
Sichuan Kelun-Biotech Biopharmaceutical (HKEX: 6990) announced Monday September 14, 2026 that Phase 3 registrational study results for trastuzumab botidotin — a novel HER2-targeted antibody-drug conjugate — versus T-DM1 (Roche's Kadcyla, trastuzumab emtansine) in HER2-positive unresectable or metastatic breast cancer have been published in the Journal of Clinical Oncology. Trastuzumab botidotin produced 11.1 months median progression-free survival versus 4.4 months on T-DM1, a hazard ratio of 0.39 (61% reduction in risk of progression or death). Co-senior authors: Professors Xichun Hu and Hongxia Wang of Fudan University Shanghai Cancer Center, and Dr. Junyou Ge. The NMPA approved trastuzumab botidotin in October 2025 for adults with unresectable or metastatic HER2-positive breast cancer who had received at least one prior anti-HER2 therapy. The T-DM1 comparator (approved 2013) has historically been the standard of care in this second-line setting, though Daiichi Sankyo/AstraZeneca's Enhertu (trastuzumab deruxtecan) has since taken market share on stronger DESTINY-Breast trial data. Kelun-Biotech has opened a Phase 2 study of trastuzumab botidotin in patients who previously received a topoisomerase inhibitor payload ADC (which includes Enhertu-treated patients). The Phase 3 result strengthens the case for global development beyond China.