CHENGDU, China, 21 May 2026
Sichuan Kelun-Biotech Biopharmaceutical Co., Ltd. announced that two registrational studies involving its lead oncology assets, sacituzumab tirumotecan (sac-TMT) and lunbotinib fumarate, will be featured in oral presentation sessions at the ASCO Annual Meeting 2026 in Chicago. The presentations focus on advanced non-small cell lung cancer (NSCLC) and showcase promising efficacy results for both the company’s TROP2-targeting antibody-drug conjugate (ADC) and its next-generation selective RET inhibitor. The data further strengthen Kelun-Biotech’s expanding oncology pipeline and reinforce its growing position in the global ADC and targeted therapy market..
Sac-TMT Combination Shows Strong Phase III NSCLC Results
The Phase III OptiTROP-Lung05 study evaluated sac-TMT plus pembrolizumab versus pembrolizumab monotherapy as first-line treatment for patients with PD-L1 positive advanced NSCLC lacking EGFR or ALK alterations. The trial enrolled 413 patients with both squamous and non-squamous NSCLC histologies. Results demonstrated a highly significant improvement in progression-free survival (PFS), with median PFS not reached in the combination arm compared with 5.7 months in the pembrolizumab-alone group. The study achieved a hazard ratio of 0.35, indicating a substantial reduction in disease progression risk.
The objective response rate (ORR) reached 70.2% in patients receiving the sac-TMT combination versus 42.0% with pembrolizumab alone. Early overall survival trends were also favorable, with a hazard ratio of 0.55 despite immature data. Benefits were consistently observed across major patient subgroups, including patients with PD-L1 TPS 1–49% and ≥50%, as well as both squamous and non-squamous disease. Safety findings showed higher rates of grade 3 or greater treatment-emergent adverse events in the combination arm, although discontinuation rates remained relatively low.
Kelun-Biotech stated that this is the first Phase III study to demonstrate significant PFS improvement using an ADC combined with pembrolizumab in first-line PD-L1 positive advanced NSCLC. Based on the results, China’s National Medical Products Administration has accepted the supplemental NDA for priority review.
Lunbotinib Delivers High Response Rates in RET-Positive NSCLC
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The company will also present registrational Phase II data for lunbotinib fumarate (A400/EP0031), a next-generation selective RET inhibitor targeting RET fusion-positive advanced NSCLC. The study enrolled both treatment-naïve patients and patients previously treated with platinum chemotherapy and immunotherapy.
Among pre-treated patients, the confirmed ORR reached 87.1%, while treatment-naïve patients achieved an ORR of 81.3%. Median progression-free survival reached 27.5 months in previously treated patients and was not yet reached in treatment-naïve patients. Notably, the drug also demonstrated strong intracranial activity in patients with baseline brain metastases, with several patients achieving complete intracranial responses.
Safety results were manageable, with no fatal treatment-related adverse events reported and only two patients discontinuing treatment due to toxicity. The company confirmed that the NDA for lunbotinib in RET fusion-positive NSCLC has already been accepted for review in China.
Kelun-Biotech Expands Global Oncology Presence
Sac-TMT is one of Kelun-Biotech’s core ADC products and has already secured multiple approvals in China across NSCLC and breast cancer indications. The therapy is notable for becoming the world’s first approved TROP2 ADC for lung cancer. The company previously licensed global rights outside Greater China to Merck & Co., known as MSD outside the United States and Canada, in a multibillion-dollar collaboration announced in 2022.
Kelun-Biotech currently has nine registrational clinical studies underway for sac-TMT in China, while MSD is conducting 17 global Phase III studies involving the therapy either as monotherapy or in combination with pembrolizumab. The company also continues advancing its proprietary OptiDCâ„¢ ADC platform, which supports a growing portfolio of oncology assets targeting major unmet medical needs worldwide.
Source: Kelun-Biotech press release
