Sichuan Kelun-Biotech Biopharmaceutical Co., Ltd. ("Kelun-Biotech" or the "Company," 6990.HK)  announced that its TROP2-directed antibody-drug conjugate (ADC) sacituzumab tirumotecan (sac-TMT, also known as SKB264/MK-2870) (佳泰莱^®) in combination with MSD's anti-PD-1 monoclonal antibody pembrolizumab (KEYTRUDA^®[1]) was granted Breakthrough Therapy Designation (BTD) by the Center for Drug Evaluation (CDE) of the National Medical Products Administration (NMPA) of China for the first-line treatment of patients with locally advanced or metastatic non-small cell lung cancer (NSCLC) who have PD-L1 tumor proportion score (TPS)≥1% and are EGFR-negative and ALK-negative. 

BTD is granted for treatment regimens that provide effective treatment or prevention for conditions with no currently available therapy, or that demonstrate significant clinical advantages over currently available treatments. For drugs included in the breakthrough therapy process, if relevant conditions are met, applications for conditional approval and priority review and approval can be submitted when applying for marketing authorization.

Previously, the company announced that results from the Phase III clinical trial of OptiTROP-Lung05, evaluating sac-TMT in combination with pembrolizumab as first-line treatment for PD-L1-positive NSCLC, demonstrated a statistically significant and clinically meaningful improvement in its primary endpoint of progression-free survival (PFS). A positive trend was also observed in overall survival (OS). OptiTROP-Lung05 is the first Phase III study of an immunotherapy and ADC combination to meet its primary endpoint in the first-line treatment of NSCLC. Granting of BTD for the first-line treatment of PD-L1-positive NSCLC indication offers pathways to expedite the review and potential approval process of sac-TMT for this indication.

To date, sac-TMT has received five BTDs for:

• locally advanced or metastatic triple-negative breast cancer (TNBC) in July 2022;
• locally advanced or metastatic EGFR-mutant NSCLC after progression on EGFR-TKI therapy in January 2023;
• locally advanced or metastatic hormone-receptor positive (HR+) and human epidermal growth factor receptor 2-negative (HER2-) breast cancer (BC) in patients who have previously received at least two lines of systemic chemotherapy in June 2023;
• first-line treatment of unresectable locally advanced, recurrent or metastatic PD-L1 negative TNBC in March 2024;
• In combination with anti-PD-L1 monoclonal antibody tagitanlimab for the first-line treatment of locally advanced or metastatic non-squamous NSCLC without actionable genomic alterations in June 2025.