Chinese biopharmaceutical company Sichuan Kelun-Biotech Biopharmaceutical Co Ltd (Kelun-Biotech) (HKG:6990) announced on Sunday the presentation at the 2026 European Society for Medical Oncology (ESMO) Congress in Madrid, Spain, of the prespecified final overall survival (OS) analysis results of the Phase III OptiTROP-Lung04 study of sacituzumab tirumotecan (sac-TMT, also known as SKB264/MK-2870).

The results showed that in patients with epidermal growth factor receptor (EGFR)-mutant locally advanced or metastatic non-squamous non-small cell lung cancer (NSCLC) who have progressed after treatment with EGFR-tyrosine kinase inhibitor (EGFR-TKI) therapy, sac-TMT monotherapy demonstrated a sustained OS benefit compared with platinum-based doublet chemotherapy.

Median OS was extended by 8.5 months compared with platinum-based doublet chemotherapy (25.9 vs 17.4 months), with a 31% reduction in the risk of death. The 2-year OS rate was 54.1% vs 37.2%, an improvement of 16.9%; with a median follow-up of 32.3 months, the survival benefit was sustained.

The adjusted median OS differed by 9.3 months (25.9 vs 16.6 months). After adjusting for the subsequent therapy with an antibody-drug conjugate (ADC) using the prespecified RPSFT model, the risk of death was reduced by 43%.

The results of the final progression-free survival (PFS) analysis and interim OS analysis of the study were published online in The New England Journal of Medicine in 2025. The final PFS analysis assessed by blinded independent central review (BICR) showed a 51% reduction in the risk of disease progression or death. Based on these results, sac-TMT was approved by the National Medical Products Administration (NMPA) of China in September 2025 for the treatment of adult patients with EGFR mutant-positive locally advanced or metastatic non-squamous NSCLC who progressed after treatment with EGFR-TKI therapy.

Sac-TMT, a core product of Kelun-Biotech, is a novel trophoblast cell-surface antigen 2 (TROP2)-targeting ADC in which the company has proprietary intellectual property rights, targeting advanced solid tumours such as NSCLC, breast cancer, gastric cancer, gynaecological tumours and genitourinary tumours, among others.