Chinese biopharmaceutical company Sichuan Kelun-Biotech Biopharmaceutical Co Ltd (HK:6990) announced on Sunday, at the 2025 European Society for Medical Oncology (ESMO) Congress held in Berlin, Germany, results from the Phase 3 OptiTROP-Lung04 trial of its trophoblast cell-surface antigen 2 (TROP2)-directed antibody-drug conjugate (ADC) sacituzumab tirumotecan (sac-TMT) in EGFR-mutated non-small cell lung cancer (NSCLC) following progression on epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs).

Professor Li Zhang from Sun Yat-sen University Cancer Center presented the data, with simultaneous publication in the New England Journal of Medicine.

A total of 376 patients were randomised 1:1 to receive sac-TMT monotherapy or chemotherapy. As at the data cut-off date in July 2025, the median follow-up was 18.9 months. The median Progression-Free Survival (PFS) was 8.3 months in the sac-TMT group and 4.3 months in the chemotherapy group. Sac-TMT significantly improved PFS over chemotherapy with 51% lower risk of disease progression or death.

The company says that as a conclusion, sac-TMT demonstrates highly statistically significant and clinically meaningful improvements in PFS and OS compared to platinum-based chemotherapy and showed a manageable safety profile, with no unexpected safety signals identified. Several global phase 3 studies of sac-TMT monotherapy and in combination with osimertinib in China in EGFR-mutant NSCLC are ongoing.

In May 2022, Kelun-Biotech licensed the exclusive rights to MSD (tradename of Merck & Co Inc) to develop, use, manufacture and commercialise sac-TMT in all territories outside of Greater China (which includes Mainland China, Hong Kong, Macao and Taiwan).

The company has now initiated nine registrational clinical studies in China. MSD has initiated 15 ongoing Phase 3 global clinical studies of sac-TMT as a monotherapy or with pembrolizumab or other anti-cancer agents for several types of cancer. These studies are sponsored and led by MSD.