Efficacy and safety of MHB088C, a novel B7-H3-targeted ADC, in patients with relapsed extensive-stage small cell lung cancer (ES-SCLC): Subgroup analysis from a phase 1/2 multicenter study.

作者：Lin Shen, Caicun Zhou, Yan Yu, Xinmin Yu, Xue Meng, Yuping Sun, Yuanyuan Ji, Yinghua Ji, Fangling Ning, Yuming Jia, Haihua Yang, Meili Sun, Qing Wen, Runxiang Yang, Yanqiu Zhao, Liang Han, Zhiye Zhang, Shiyu Zhou, Junwei Shi, Guoqing Cao · 发表于：Journal of Clinical Oncology · 年份：2025 · DOI：10.1200/jco.2025.43.16_suppl.8510 · 被引用次数：6 · 研究领域：Lung Cancer Research Studies、Peptidase Inhibition and Analysis、Cancer therapeutics and mechanisms

8510 Background: MHB088C is a novel B7-H3-targeted antibody-drug conjugate (ADC) containing the potent SuperTopoi payload that is 5 to 10 times more potent than Dxd. Initial findings from an ongoing phase 1/2 study indicated that MHB088C was generally well tolerated, with early signs of clinical activity (ASCO 2024, abstract #3012). This analysis presents efficacy and safety results for the subset of pts with ES-SCLC. Methods: This study consisted of 2 parts: dose-escalation (part 1) and expansion (part 2). Part 1 evaluated the safety and tolerability of MHB088C at doses ranging from 0.8 to 4.0 mg/kg, administered intravenously every 2 (Q2W) or 3 weeks (Q3W). Doses of 1.6 mg/kg Q2W, 2.0 mg/kg Q2W, and 2.4 mg/kg Q3W were selected for part 2. Part 2 focused on assessing safety and prospective efficacy of MHB088C in selected tumor types, including SCLC. Results: At data cutoff (January 3, 2025), a total of 91 pts with relapsed ES-SCLC had received ≥ 1 dose of MHB088C (1.6 mg/kg Q2W, n=28; 2.0 mg/kg Q2W, n=33; 2.4 mg/kg Q3W, n=30). MHB088C showed encouraging efficacy in relapsed ES-SCLC (Table). The objective response rates were 42.9%, 57.6%, and 46.7% in the 1.6, 2.0, and 2.4 mg/kg cohorts, respectively, with median progression-free survival (PFS) of 5.5, 5.9, 5.5 months. Safety data were consistent with previous reports. The most common grade≥3 treatment-related adverse events were neutropenia, platelet count decreased and anemia. The 1.6 and 2.0 mg/kg cohorts exhibited favorab...