Sichuan Kelun-Biotech Biopharmaceutical Co., Ltd. (the "Company") announced that a new indication application (the "Application") for the Company's trophoblast cell-surface antigen 2 (TROP2)-directed antibody-drug conjugate (ADC) sacituzumab tirumotecan (sac-TMT, also known as SKB264/MK-2870) was accepted by the Center for Drug Evaluation (CDE) of the National Medical Products Administration (NMPA) of China for the treatment of adult patients with unresectable locally advanced, metastatic hormone-receptor positive (HR+) and human epidermal growth factor receptor 2-negative (HER2-) breast cancer (BC) who have received prior endocrine therapy and other systemic treatments in the advanced or metastatic setting. This acceptance is based on the positive results from the registrational phase 3 OptiTROP-Breast02 study, and the Application is the fourth indication application for sac-TMT that has been accepted by the NMPA.

OptiTROP-Breast02 is a randomized, open-label, multi-center, Phase 3 clinical study that evaluates the efficacy and safety results of sac-TMT monotherapy 5mg/kg every other week (Q2W) versus chemotherapy treatment of physician's choice for the treatment of patients with unresectable locally advanced or metastatic HR+/HER2- (Immunohistochemistry [IHC] 0, IHC 1+ or IHC 2+/ In Situ Hybridization [ISH]-) BC. Primary efficacy endpoint of this Phase 3 clinical study was reached according to a pre-specified interim analysis, where sac-TMT monotherapy demonstrated a statistically significant and clinically meaningful improvement in the primary endpoint of progression-free survival (PFS) as assessed by the blinded independent review committee (BIRC) compared with chemotherapy treatment of physician's choice and the risk of disease progression or death was significantly reduced. Sac-TMT also demonstrated the beneficial trend for overall survival (OS).

On May 16, 2024, the CDE's official website announced that the Application would be reviewed via the priority review and approval process. This marks the fourth sac-TMT indication to go through the CDE's priority review and approval process, with three previous sat-TMT indications approved following priority review.

Dr. Michael Ge, CEO of Kelun-Biotech said, "We are very pleased that the NDA application for the fourth indication of our core product, sac-TMT, has been accepted by the CDE of NMPA, which is another breakthrough for the breast cancer treatment field. This not only verifies the clinical value and innovative nature of sac-TMT, but also highlights the 'patient-centered' mission of Kelun-Biotech. We look forward to the OS results of sac-TMT with longer follow-up. In the future, we will continue to explore sac-TMT as an oncology therapeutic agent, aiming to address new indications with unmet clinical needs, so as to benefit more oncology patients globally."