Core Viewpoint - Sichuan Kelun Pharmaceutical Co., Ltd. announced that its subsidiary, Sichuan Kelun Botai Biopharmaceutical Co., Ltd., has received acceptance from the National Medical Products Administration (NMPA) for a New Drug Application (NDA) for the RET small molecule kinase inhibitor A400 (also known as EP0031) for the treatment of RET fusion-positive locally advanced or metastatic non-small cell lung cancer (NSCLC) in adult patients [1][2]. Drug Overview - The KL400-I/II-01 study includes two key Phase II cohorts assessing the efficacy and safety of A400/EP0031 at a dosage of 90 mg orally once daily for treating RET fusion-positive locally advanced or metastatic NSCLC patients, both treatment-naive and previously treated [1]. - The primary efficacy endpoints of the two key clinical study cohorts have been met, demonstrating good efficacy of A400/EP0031 in NSCLC patients, including those previously treated with immunotherapy or with brain metastases [1]. - A400 is a next-generation selective RET inhibitor aimed at treating NSCLC, medullary thyroid carcinoma (MTC), and other solid tumors with high prevalence of RET mutations [2]. Clinical Development - Kelun Botai is currently conducting a Phase 1b/2 clinical study in China targeting RET+ MTC and solid tumors [2]. - The Phase I study results for A400/EP0031 in advanced RET-mutant MTC patients were presented at the 2025 ASCO Annual Meeting [2]. - In March 2024, A400/EP0031 received Fast Track designation from the U.S. Food and Drug Administration (FDA) for the treatment of RET fusion-positive NSCLC, and in April 2024, it was approved to enter Phase 2 clinical development, with trials ongoing in the U.S., U.K., EU, and UAE [2].