SKB BIO (06990.HK): seventh sac-TMT indication filing accepted, first-line PD-L1-negative non-squamous NSCLC

NewTimeSpace News: SKB BIO (06990.HK) released a voluntary announcement that a new indication application of its trophoblast cell-surface antigen 2 (TROP2)-directed antibody drug conjugate (ADC) sacituzumab tirumotecan (sac-TMT, also known as SKB264/MK-2870) has been accepted for review by the Center for Drug Evaluation (CDE) of the National Medical Products Administration (NMPA) of China, in combination with MSD's anti-programmed cell death protein 1 (PD-1) monoclonal antibody pembrolizumab (KEYTRUDA®) as first-line treatment for adult patients with locally advanced or metastatic non-squamous non-small cell lung cancer (NSCLC) whose tumours have a programmed cell death ligand 1 (PD-L1) tumour proportion score (TPS) <1% and are epidermal growth factor receptor (EGFR)-negative and anaplastic lymphoma kinase (ALK)-negative. This marks the seventh indication application for sac-TMT accepted for review by the NMPA.

According to the announcement, the application is based on positive results from the Phase 3 registrational OptiTROP-Lung06 study, which evaluated sac-TMT in combination with pembrolizumab against pembrolizumab plus chemotherapy as first-line treatment for patients with PD-L1-negative locally advanced or metastatic non-squamous NSCLC, directly comparing two treatment strategies - "ADC plus immunotherapy" versus "immunotherapy plus chemotherapy". At a prespecified interim analysis, sac-TMT plus pembrolizumab demonstrated a statistically significant and clinically meaningful improvement in the primary endpoint of progression-free survival (PFS) as assessed by blinded independent central review (BICR) compared with pembrolizumab plus pemetrexed and platinum-based chemotherapy, and a positive trend was also observed in the secondary endpoint of overall survival (OS); the safety profile of the combination was consistent with previous studies, with no new safety signals observed. The study has been selected as a late-breaking abstract (LBA) at the 2026 European Society for Medical Oncology (ESMO) Congress, with detailed results presented as an oral report.

Sac-TMT is a novel TROP2 ADC in which the Company holds proprietary intellectual property rights, developed with a unique bifunctional linker and a drug-to-antibody ratio (DAR) of 7.4 that also enables a bystander effect. In May 2022, the Company granted MSD the exclusive rights to develop, use, manufacture and commercialise sac-TMT in all territories outside Greater China. To date, four indications of sac-TMT have been approved for marketing in China, the first two of which have been included in the national medical insurance scheme, and the drug has received six breakthrough therapy designations from the NMPA, making it the world's first TROP2 ADC approved for a lung cancer indication.

Including the current application, three new indication applications for sac-TMT have been accepted by the NMPA, with the first two included in the priority review process. The Company is currently conducting nine registrational clinical studies in China, while MSD has initiated 18 ongoing global Phase 3 clinical studies. The Company cautioned that sac-TMT, which has not yet been approved for other indications, may not ultimately be successfully developed and commercialised, and shareholders and potential investors are advised to exercise caution when dealing in the securities of the Company.