Sichuan Kelun-Biotech Biopharmaceutical Co., Ltd. (Kelun-Biotech) announced that the National Medical Products Administration (NMPA) has accepted for review the company’s sixth indication application for its core asset sacituzumab tirumotecan (sac-TMT, SKB264/MK-2870, tradename 佳泰萊®). The submission seeks approval for first-line treatment of unresectable recurrent or metastatic triple-negative breast cancer (TNBC) in patients with a PD-L1 combined positive score (CPS) < 10, or in those who relapse after prior PD-1/PD-L1 inhibitor therapy at the early stage. The file has been placed on the NMPA’s priority review and approval pathway.
The application is supported by positive data from the randomized, open-label, multicenter Phase 3 OptiTROP-Breast03 trial, which compared sac-TMT with investigator’s-choice chemotherapy in systemic therapy-naïve patients with advanced TNBC. The study met its primary efficacy endpoints, delivering statistically significant and clinically meaningful superiority over chemotherapy across key outcome measures. Detailed trial metrics were not disclosed in the announcement.
Sac-TMT, a proprietary TROP2-targeting antibody–drug conjugate (ADC) with a drug-to-antibody ratio of 7.40, combines an anti-TROP2 monoclonal antibody with a belotecan-derived topoisomerase I inhibitor payload via a bifunctional linker designed for enhanced payload delivery and by-stander effect. In May 2022 Kelun-Biotech licensed ex-Greater China rights to Merck & Co. (MSD), which is currently sponsoring 17 global Phase 3 trials of sac-TMT; Kelun-Biotech is conducting nine registrational studies in China.
Four sac-TMT indications are already approved domestically: 1) Third-line and beyond therapy for unresectable or metastatic TNBC; 2) EGFR-mutant non-squamous NSCLC after EGFR-TKI and platinum chemotherapy; 3) EGFR-mutant non-squamous NSCLC post-EGFR-TKI (regardless of prior chemotherapy); and 4) HR-positive/HER2-negative breast cancer after endocrine therapy and at least one chemotherapy line. The first two indications are listed in China’s National Reimbursement Drug List (NRDL).
Alongside the new TNBC filing, another priority review is underway for sac-TMT in combination with pembrolizumab as first-line therapy for PD-L1 TPS ≥ 1%, EGFR-negative/ALK-negative advanced NSCLC. Sac-TMT also holds six Breakthrough Therapy Designations from the NMPA and is the first TROP2 ADC globally approved for lung cancer.
Risk reminder: sac-TMT for unapproved indications remains under clinical development and may ultimately fail to secure regulatory clearance. Investors should exercise caution when dealing in SKB BIO securities.