On May 22, 2025, Kelun Bio announced that the application for a new indication of its trophoblast cell surface antigen 2 (TROP2)-directed antibody-drug conjugate (ADC) sacituzumab tirumotecan (sac-TMT, also known as SKB264/MK – 2870) (®) had been accepted by the Center for Drug Evaluation (CDE) of the National Medical Products Administration (NMPA) of China. This new indication is for the treatment of adult patients with unresectable locally advanced or 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 therapies in the advanced or metastatic setting. This acceptance was based on the positive results of the registration Phase 3 OptiTROP – Breast02 study. This application is the fourth indication application for sac – TMT accepted by the NMPA.
OptiTROP – Breast02 is a randomized, open-label, multicenter, Phase 3 clinical study that evaluated the efficacy and safety of sacituzumab tirumotecan monotherapy at a dose of 5 mg/kg every two weeks (Q2W) compared with physician’s choice of chemotherapy in patients with unresectable locally advanced or metastatic HR+/HER2- (immunohistochemistry [IHC] 0, IHC 1+, or IHC 2+/in situ hybridization [ISH]-) breast cancer. Based on the pre-specified interim analysis, the primary efficacy endpoint of this Phase 3 clinical study was met. Compared with physician’s choice of chemotherapy, sac – TMT monotherapy showed 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), with a significantly reduced risk of disease progression or death. Sac – TMT also showed a favorable trend in 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.
About sac-TMT (佳泰莱®)
Sac-TMT, a core product of the Company, is a novel human TROP2 ADC in which the Company has proprietary intellectual property rights, targeting advanced solid tumors such as non-small cell lung cancer (NSCLC), BC, gastric cancer (GC), gynecological tumors, among others. Sac-TMT is developed with a novel linker to conjugate the payload, a belotecan-derivative topoisomerase I inhibitor with a drug-to-antibody-ratio (DAR) of 7.4. Sac-TMT specifically recognizes TROP2 on the surface of tumor cells by recombinant anti-TROP2 humanized monoclonal antibodies, which is then endocytosed by tumor cells and releases KL610023 intracellularly. KL610023, as a topoisomerase I inhibitor, induces DNA damage to tumor cells, which in turn leads to cell-cycle arrest and apoptosis. In addition, it also releases KL610023 in the tumor microenvironment. Given that KL610023 is membrane permeable, it can enable a bystander effect, or in other words kill adjacent tumor cells.
At present, there are still many clinical trials of new anti-cancer technologies in China seeking patients. Consultation on new drugs and technologies, you can contact Beijing South Region Oncology Hospital International Department.
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Post time: May-27-2025