Core Viewpoint - Sichuan Kelun Pharmaceutical Co., Ltd. announced that its subsidiary, Sichuan Kelun Botai Biopharmaceutical Co., Ltd., received approval from the National Medical Products Administration (NMPA) for the fourth indication of its core product, TROP2 ADC, sac-TMT, for the treatment of 2L+ HR+/HER2- breast cancer [2][6]. Drug Basic Information - The approval is based on positive results from the OptiTROP-Breast02 Phase III clinical study, which was presented at the 2025 European Society for Medical Oncology (ESMO) Congress [2][3]. - The new indication is for adult patients with unresectable or metastatic HR+/HER2- breast cancer who have previously received endocrine therapy and at least one line of chemotherapy [2][3]. Clinical Study Results - The OptiTROP-Breast02 study evaluated the efficacy and safety of sac-TMT compared to investigator's choice of chemotherapy in patients with HR+/HER2- breast cancer [3]. - Among enrolled patients, 95.7% had visceral metastases, and 75.9% had liver metastases [3]. - The study showed a significant improvement in progression-free survival (PFS) for the sac-TMT group compared to the chemotherapy group (8.3 months vs. 4.1 months; hazard ratio (HR): 0.35; 95% confidence interval (CI): 0.26-0.48; p<0.0001) [3]. - The overall survival (OS) benefit trend and objective response rate (ORR) were also significantly higher in the sac-TMT group (41.5% vs. 24.1%) [3]. Product Overview - Sac-TMT is a novel TROP2 ADC developed by Kelun Botai, targeting various advanced solid tumors, including non-small cell lung cancer (NSCLC), breast cancer (BC), gastric cancer (GC), and gynecological tumors [5]. - The drug utilizes a new linker and has a drug-antibody ratio (DAR) of 7.4, delivering a topoisomerase I inhibitor as an effective payload [5]. - Sac-TMT has received six breakthrough therapy designations (BTD) from the NMPA [6]. Ongoing Research - Currently, sac-TMT is involved in nine registration clinical studies in China, with Merck conducting 16 ongoing global Phase III clinical studies for various cancer types [7].