CHENGDU, China, May 30, 2026 /PRNewswire/ -- Sichuan Kelun-Biotech Biopharmaceutical Co., Ltd. (the "Company", 6990.HK) announced that at the 2026 American Society of Clinical Oncology (ASCO) Annual Meeting held in Chicago, USA, results from the pivotal Phase II study of the Company's next-generation selective RET inhibitor, lunbotinib fumarate (A400/EP0031, 宁泰莱^®[1]), in advanced rearranged during transfection (RET) fusion-positive non-small cell lung cancer (NSCLC) were presented as an oral report by Professor Qing Zhou from Guangdong Provincial People's Hospital (Abstract #8505, Lung Cancer—Metastatic Non-Small Cell). Based on these results, a New Drug Application (NDA) for lunbotinib fumarate for the treatment of adult patients with locally advanced or metastatic RET fusion-positive NSCLC has been accepted by the National Medical Products Administration (NMPA) of China.

The study enrolled 71 patients who had previously received platinum-based chemotherapy and immunotherapy (pre-treated patients) and 92 patients who had not received prior systemic therapy (treatment-naïve patients). As of the data cutoff date of October 29, 2025, the median follow-up was 22.6 months and 20.7 months, respectively.

The confirmed objective response rate (ORR) assessed by Independent Review Committee (IRC) was 81.3% (95% CI: 71.8–88.7) in treatment-naïve patients and 87.1% (95% CI: 77.0–93.9) in pre-treated patients.

In treatment-naïve patients, median duration of response (mDOR) and median progression-free survival (mPFS) were not reached. In pre-treated patients, mDOR was 25.7 months, and mPFS was 27.5 months.

Among 40 patients with central nervous system (CNS) metastases at baseline (assessed by IRC per response assessment in neuro-oncology brain metastases (RANO-BM) criteria), the intracranial complete response (CR) rate was 30%, and the disease control rate (DCR) was 92.5% (95% CI: 79.6–98.4).

Lunbotinib fumarate was well tolerated, with treatment-related adverse events (TRAEs) being predominantly Grade 1–2. The rate of permanent discontinuation due to TRAEs was 1.2%, and no treatment-related deaths were reported.

The study shows that lunbotinib fumarate demonstrated robust and durable clinical activity in RET fusion-positive NSCLC, regardless of line of therapy, in a largely poor-prognostic patient population. Favorable CNS efficacy was observed in patients with measurable baseline CNS metastases. The safety profile was manageable, with no unexpected safety signals.

Professor Qing Zhou, principal investigator from Guangdong Provincial People's Hospital, said: "From the first presentation of Phase I data at ASCO 2023 to today's pivotal Phase II results, we have witnessed the progression of lunbotinib fumarate from early exploration to a confirmatory study. These data show that lunbotinib fumarate delivers robust and durable responses in both treatment-naïve and pre-treated patients with RET fusion-positive NSCLC, with particularly remarkable intracranial efficacy in patients with CNS metastases at baseline. As a next-generation selective RET inhibitor, it will offer an important new treatment option for patients."

About lunbotinib fumarate (A400/EP0031, 宁泰莱^®)

Lunbotinib fumarate is a novel, next-generation selective RET inhibitor for NSCLC, medullary thyroid cancer (MTC) and other solid tumors with a high prevalence of RET alterations. The NDA of lunbotinib fumarate has been accepted for review by the NMPA of China for the treatment of adult patients with RET-fusion positive locally advanced or metastatic NSCLC. The Company is also conducting a Phase Ib/II clinical study in China for the treatment of RET-positive solid tumors.

In March 2021, the Company granted Ellipses Pharma Limited, a U.K.-based international oncology drug development company, an exclusive license to develop, manufacture and commercialize this agent outside Greater China and certain Asian countries. In April 2024, lunbotinib fumarate was cleared by the Food and Drug Administration (FDA) to progress into a Phase II clinical trial (NCT05443126) which is currently recruiting in the United States, United Kingdom, Europe and United Arab Emirates, where it is being evaluated as a monotherapy and in combination with chemotherapy in RET fusion positive advanced NSCLC.

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, 1 project is 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/.