• PFS was significantly prolonged: as assessed by BICR, the risk of disease progression or death was reduced by 51% (HR 0.49; 95% CI 0.36-0.65; P<0.0001 ), and median PFS was 15.0 months (95% CI 9.9-NE) and 5.7 months (95% CI 5.5-7.4) in the two groups, respectively.
• Responses were more durable: median duration of response was 13.6 months and 6.8 months in the two groups, respectively (HR 0.47; 95% CI 0.29-0.77).
• OS showed a trend of improvement: at this PFS interim analysis, the OS HR was 0.58 (95% CI 0.38-0.88), and median OS was not reached in both groups.

CHENGDU, China, Oct. 25, 2026 /PRNewswire/ -- Sichuan Kelun-Biotech Biopharmaceutical Co., Ltd. ("Kelun-Biotech" or the "Company", 6990.HK) announced that at the 2026 European Society for Medical Oncology (ESMO) Congress in Madrid, Spain, the results of the Phase III OptiTROP-Lung06 study of sacituzumab tirumotecan (sac-TMT, also known as SKB264/MK-2870) (佳泰莱^®) were presented as an oral presentation by Professor Caicun Zhou from the Shanghai East Hospital, Tongji University (LBA66; Proffered paper | NSCLC, Metastatic).

The findings of OptiTROP-Lung06 have also been simultaneously published in the medical journal The New England Journal of Medicine (Impact Factor=84.5).

The interim analysis showed that sacituzumab tirumotecan (sac-TMT) plus MSD^[1]'s anti-programmed cell death protein 1 (PD-1) monoclonal antibody pembrolizumab (KEYTRUDA^®[2]) demonstrated significant improvement in progression-free survival (PFS) compared with platinum-based doublet chemotherapy plus pembrolizumab in first-line treatment of patients with programmed cell death ligand 1 (PD-L1) tumor proportion score (TPS) <1%, epidermal growth factor receptor (EGFR) mutation-negative and anaplastic lymphoma kinase (ALK)-negative advanced non-squamous non-small cell lung cancer (NSCLC). A trend toward benefit in overall survival (OS) was also observed.

As assessed by blinded independent central review (BICR), the objective response rate was 50.2% and 47.3% in the two groups, respectively; the deep response rate was 28.8% and 17.3%, respectively. Deep response was defined as achieving complete or partial response with at least a 50% reduction in the sum of target lesion diameters from baseline.

In terms of safety, the safety profile of sac-TMT plus pembrolizumab was generally consistent with those known to individual agents. No new safety signals were observed. Compared with the platinum-based doublet chemotherapy plus pembrolizumab group, the sac-TMT combination treatment group had lower incidences of Grade ≥3 treatment-emergent adverse events (TEAEs), and lower incidences of TEAEs leading to dose reduction or permanent discontinuation. The incidence of interstitial lung disease/pneumonitis was similar between the two groups.

Professor Caicun Zhou from the Shanghai East Hospital, Tongji University said: "With the readout of the OptiTROP-Lung06 study results, we have further seen the clinical value of sac-TMT plus pembrolizumab regimen in the first-line treatment of PD-L1-negative, EGFR/ALK-negative advanced non-squamous NSCLC. Together with the OptiTROP-Lung05 results previously presented at 2026 ASCO, this combination regimen has shown PFS benefit in patients with NSCLC without actionable genomic alterations, regardless of PD-L1 expression, providing new Phase III evidence as first-line treatment.

OptiTROP-Lung06 Study

OptiTROP-Lung06 (NCT06711900) is a randomized, multicenter, open-label Phase III study. A total of 455 patients were enrolled and randomized 1:1 to receive sac-TMT plus pembrolizumab or platinum-based doublet chemotherapy (pemetrexed plus cisplatin or carboplatin) plus pembrolizumab. The primary endpoint is PFS assessed by BICR, and secondary endpoints include OS. As of the data cut-off date of June 9, 2026, the median follow-up was 9.7 months. This is the world's first Phase III clinical study of an ADC combined with an immune checkpoint inhibitor to meet its primary endpoint in the first-line treatment of driver gene-negative, PD-L1-negative non-squamous NSCLC.

About sac-TMT(佳泰莱^®)

Sac-TMT, a core product of the Company, is a novel 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 and genitourinary tumors, among others. Sac-TMT is developed with a unique, bifunctional linker that maximizes payload delivery to tumor cells both through its irreversible connection with the anti-TROP2 monoclonal antibody sacituzumab and its pH-sensitive cleavage from a belotecan-derivative topoisomerase I inhibitor payload (KL610023) in the lysosome, 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 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 (which includes Mainland China, Hong Kong, Macao and Taiwan).

To date, four indications for sac-TMT have been approved and marketed in China for: 1) 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); 2) EGFR mutant-positive locally advanced or metastatic non-squamous NSCLC following progression on EGFR-tyrosine kinase inhibitor (TKI) therapy and platinum-based chemotherapy; 3) EGFR mutant-positive locally advanced or metastatic non-squamous NSCLC who progressed after treatment with EGFR-TKI therapy; 4) unresectable or metastatic hormone receptor-positive (HR+)/human epidermal growth factor receptor 2-negative (HER2-) (Immunohistochemistry (IHC) 0, IHC 1+ or IHC 2+/In Situ Hybridization (ISH)-) BC who have received prior endocrine therapy and at least one line of chemotherapy in advanced setting. The first two indications above have been included in China's National Reimbursement Drug List (NRDL). This inclusion is expected to bring clinically meaningful benefits to a greater number of patients with BC and NSCLC. Additionally, sac-TMT has been granted six Breakthrough Therapy Designations by the NMPA.

Sac-TMT is the world's first TROP2 ADC drug approved for marketing in lung cancer. Two new indication applications have been accepted for review by the NMPA: 1) sac-TMT in combination with pembrolizumab as first‑line treatment for locally advanced or metastatic NSCLC who have PD-L1 TPS ≥1% and are EGFR-negative and ALK-negative; 2) sac‑TMT as first‑line treatment for patients with recurrent or metastatic TNBC who have a PD‑L1 combined positive score (CPS) <10 or have recurred after prior PD‑1/PD‑L1 inhibitor therapy in the early stage, both of the above two applications have been included in the priority review and approval process. As of today, the Company has initiated 9 registrational clinical studies in China. MSD has initiated 18 ongoing global Phase III clinical studies of sac-TMT as a monotherapy or in combination with pembrolizumab 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, which focuses on the R&D, manufacturing, commercialization and global collaboration of innovative biological drugs and small molecule drugs. Kelun-Biotech focuses on major disease areas such as solid tumors, autoimmune, 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. Kelun-Biotech is committed to becoming a leading global enterprise in the field of innovative drugs. At present, Kelun-Biotech has more than 30 ongoing key innovative drug projects, of which 4 projects with 8 indications have been approved for marketing, 2 projects with 3 indications are in the NDA stage and more than 10 projects are in the clinical stage. Kelun-Biotech has established one of the world's leading proprietary ADC and novel DC platforms, OptiDC™, and has 2 ADC projects with 5 indications approved for marketing, and multiple ADC and novel DC assets in clinical or preclinical research stage. For more information, please visit: https://en.kelun-biotech.com/.

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