The New England Journal of Medicine Publishes Results of Phase III OptiTROP-Lung04 Study of Sacituzumab Tirumotecan in Advanced EGFR-TKI-Resistant NSCLC

• After a median follow-up of 18.9 months, the median PFS was 8.3 months in the sac-TMT group and 4.3 months in the chemotherapy group (hazard ratio (HR), 0.49; 95% confidence interval (CI), 0.39 to 0.62; two-sided P<0.0001).
• OS was significantly longer with sac-TMT than with chemotherapy (HR, 0.60; 95% CI, 0.44 to 0.82; two-sided P=0.001); 18-month OS rate was 65.8% and 48.0%, respectively. In the supplementary analysis, in which data were censored at the start date of subsequent ADC, the HR was 0.56 (95% CI, 0.41 to 0.77).
• Sac-TMT was associated with a higher incidence of stomatitis with most cases being mild and with grade 3 or higher cases reported in very few patients (4.8%; all were grade 3). Low incidence of ocular-surface toxic effects, no ILD or pneumonitis, and one infusion-related reaction (grade 2) was reported in the sac-TMT group.

CHENGDU, China, Oct. 20, 2025 /PRNewswire/ -- On October 20, Sichuan Kelun-Biotech Biopharmaceutical Co., Ltd. (the "Company") announced that the results from the Phase III registrational clinical study OptiTROP-Lung04—led by Professor Zhang Li's team from Sun Yat-sen University Cancer Center—were published in the New England Journal of Medicine (Impact Factor = 78.5). The study evaluated the efficacy and safety of the TROP2 antibody-drug conjugate (ADC) sacituzumab tirumotecan (sac-TMT) monotherapy versus pemetrexed plus platinum chemotherapy for the treatment of patients with epidermal growth factor receptor (EGFR)-mutant locally advanced or metastatic non-squamous non-small cell lung cancer (NSCLC) who have progressed failed after treatment with EGFR-tyrosine kinase inhibitor (TKI) therapy. The study was also selected as a Late-Breaking Abstract (LBA) at the 2025 European Society for Medical Oncology (ESMO) Congress and was presented as an oral report in the Presidential Symposium (Presentation # LBA5).   

OptiTROP-Lung04 is a randomized, open-label, multicenter Phase III study designed to evaluate the efficacy and safety of sac-TMT monotherapy versus pemetrexed plus platinum in patients with EGFR-mutated locally advanced or metastatic NSCLC who had progressed on prior EGFR-TKI therapy. Eligible patients were those with histologically and/or cytologically confirmed disease. The primary endpoint was Progression-Free Survival (PFS) assessed by a Blinded Independent Review Committee (BIRC) per RECIST v1.1, and the key secondary endpoint was overall survival (OS). Results showed that compared with platinum-based doublet chemotherapy, sac-TMT monotherapy demonstrated a statistically significant and clinically meaningful improvement in both PFS and OS. Consistent PFS and OS benefits were observed across all prespecified subgroups, including prior EGFR-TKI therapy, presence of liver or brain metastases, and EGFR mutation subtype.

Based on the positive results of the OptiTROP-Lung04 study, sac-TMT has been approved by the National Medical Products Administration (NMPA) in China for the treatment of adult patients with EGFR mutation-positive locally advanced or metastatic non-squamous NSCLC who have progressed after EGFR-TKI therapy. To date, sac-TMT monotherapy remains the only approved treatment option for advanced EGFR-mutant NSCLC patients who have progressed after prior TKI therapy, as well as those who have progressed after prior TKI and platinum-based chemotherapy (either concurrently or sequentially). This achievement provides comprehensive coverage for the entire population of TKI-resistant patients.

Dr. Michael Ge, Chief Executive Officer of Kelun-Biotech, commented: "OptiTROP-Lung04 is a key study that propels sac-TMT from late-line to an earlier-line treatment-setting in lung cancer, achieving a significant improvement in overall survival. We are thrilled that the results have been published in The New England Journal of Medicine, allowing this important finding to be shared widely among medical professionals and providing a reference for future lung cancer research. Together with our partner MSD, we will continue to advance sac-TMT's clinical development and regulatory approvals, covering broader lung cancer and other indications, with the goal of making sac-TMT a cornerstone therapy for the benefit of patients."

Professor Shengxiang Ren from the Department of Oncology at Shanghai Pulmonary Hospital, Tongji University, stated: "The application of third-generation EGFR-TKIs has significantly improved the overall prognosis for patients with advanced EGFR-mutant NSCLC. However, drug resistance is almost inevitable. Traditional treatment after resistance involves platinum-based doublet chemotherapy, which offers limited overall benefit. In recent years, regimens of chemotherapy plus immune checkpoint inhibitors+anti-angiogenic agents, or EGFR/c-Met bsAb, or PD-1/VEGF bsAb, have been successively approved for this indication. However, all these approaches are chemotherapy-based, highlighting an urgent need to explore novel treatment regimens. The OptiTROP-Lung04 study confirms sac-TMT as the first treatment option as a monotherapy to deliver clear dual benefits in both PFS and OS following EGFR-TKI progression. The sequential application of sac-TMT prior to chemotherapy demonstrates strong competence, establishing itself as a new standard of care for patients with advanced EGFR-mutant lung cancer after TKI resistance."

About Sac-TMT

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 NSCLC, breast cancer (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 the payload 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.

In May 2022, the Company licensed the exclusive rights to MSD (the tradename of Merck & Co., Inc., Rahway, NJ, USA) to develop, use, manufacture and commercialize sac-TMT in all territories outside of Greater China (includes Mainland China, Hong Kong, Macau, and Taiwan).

To date, three indications for sac-TMT have been approved and marketed in China for the treatment of adult patients with unresectable locally advanced or metastatic triple negative breast cancer (TNBC) who have received at least two prior systemic therapies (at least one of them for advanced or metastatic setting), EGFR mutation-positive locally advanced or metastatic non-squamous NSCLC following progression on EGFR-TKI therapy and platinum-based chemotherapy and EGFR mutant-positive locally advanced or metastatic non-squamous NSCLC who progressed after treatment with EGFR-TKI therapy. Sac-TMT is the first TROP2 ADC drug approved for marketing in lung cancer globally. In addition, the new indication application for sac-TMT for the treatment of adult patients with unresectable locally advanced, metastatic hormone receptor positive (HR+) and human epidermal growth factor receptor 2-negative (HER2-) BC who have received prior endocrine therapy and other systemic treatments in the advanced or metastatic setting was accepted by the Center for Drug Evaluation of the NMPA, and was included in the priority review and approval process.

As of today, the Company has initiated 9 registrational clinical studies in China. MSD has initiated 15 ongoing Phase Ⅲ global clinical studies of sac-TMT as a monotherapy or with pembrolizumab¹ or other anti-cancer agents for several types of cancer. These studies are sponsored and led by MSD.

About Kelun-Biotech

Kelun-Biotech (6990.HK) is a holding subsidiary of Kelun Pharmaceutical (002422.SZ), which focuses on the R&D, manufacturing, commercialization and global collaboration of innovative biological drugs and small molecule drugs. The company focuses on major disease areas such as solid tumors, autoimmune, inflammatory, and metabolic diseases, and in establishing a globalized drug development and industrialization platform to address the unmet medical needs in China and the rest of world. The Company is committed to becoming a leading global enterprise in the field of innovative drugs. At present, the Company has more than 30 ongoing key innovative drug projects, of which 4 projects have been approved for marketing, 1 project is in the NDA stage and more than 10 projects are in the clinical stage. The company has established one of the world's leading proprietary ADC and novel DC platforms, OptiDC™, and has 2 ADC projects approved for marketing, and multiple ADC and novel DC assets in clinical or preclinical research stage. For more information, please visit https://kelun-biotech.com/.

SOURCE Sichuan Kelun-Biotech Biopharmaceutical Co., Ltd.