Kelun-Biotech Presents Pivotal Phase II Data for Lunbotinib Fumarate (A400/EP0031) in RET Fusion-Positive NSCLC at 2026 ASCO
Sichuan Kelun-Biotech Biopharmaceutical Co., Ltd. has announced the presentation of results from a pivotal Phase II study of its next-generation selective RET inhibitor, lunbotinib fumarate, at the 2026 American Society of Clinical Oncology (ASCO) Annual Meeting in Chicago. The study focused on patients with advanced rearranged during transfection (RET) fusion-positive non-small cell lung cancer (NSCLC) and was presented as an oral report by Professor Qing Zhou from Guangdong Provincial People's Hospital. Based on the study results, a New Drug Application (NDA) for lunbotinib fumarate has been accepted by the National Medical Products Administration (NMPA) of China for adult patients with locally advanced or metastatic RET fusion-positive NSCLC.
The Phase II study enrolled 163 patients, including 71 who had previously received platinum-based chemotherapy and immunotherapy, and 92 who had not undergone any prior systemic therapy. As of the data cutoff date of October 29, 2025, the median follow-up for treatment-naïve and pre-treated patients was reported to be 22.6 months and 20.7 months, respectively.
The confirmed objective response rate (ORR) was assessed by the Independent Review Committee (IRC) and showed 81.3% in treatment-naïve patients and 87.1% in pre-treated patients. In terms of clinical outcomes, the median duration of response (mDOR) and median progression-free survival (mPFS) were not reached for treatment-naïve patients, while for pre-treated patients, mDOR was 25.7 months, and mPFS was 27.5 months. Among patients with central nervous system (CNS) metastases, the intracranial complete response (CR) rate was 30%, and the disease control rate (DCR) was 92.5%.
Lunbotinib fumarate was noted for its tolerability, with treatment-related adverse events (TRAEs) primarily classified as Grade 1-2 and a low rate of permanent discontinuation due to TRAEs at 1.2%. No treatment-related deaths were reported. The study suggests that lunbotinib fumarate provides significant clinical activity in RET fusion-positive NSCLC patients, including favorable efficacy in those with CNS metastases, with a manageable safety profile.
Professor Qing Zhou commented on the progression of lunbotinib fumarate from early exploration to confirmatory studies, stating that the data reflects robust responses in both treatment-naïve and pre-treated patients, highlighting its potential as a new treatment option for individuals with RET fusion-positive NSCLC. The company is also conducting a Phase Ib/II clinical study for RET-positive solid tumors and has granted Ellipses Pharma Limited an exclusive license for commercialization outside Greater China.