Multicenter phase 1-1b trial of the B7H3 targeting antibody drug conjugate YL201 for advanced solid tumors

YL201 is a novel B7H3-targeting antibody-drug conjugate. A multicenter phase 1/1b trial evaluated YL201 in patients with advanced solid tumors refractory to standard therapies. A total of 312 patients across multiple tumor types were enrolled, including extensive-stage small cell lung cancer, nasopharyngeal carcinoma, non-small cell lung cancer, esophageal squamous cell carcinoma, and other solid tumors. In the dose-escalation part of the study, the maximum tolerated dose was determined to be 2.8 mg/kg every 3 weeks, and the recommended expansion dose was selected as 2.0 and 2.4 mg/kg every 3 weeks. The most common grade 3 or higher treatment –related adverse events were neutropenia (31.7% of patients), leukopenia (29.5%), and anemia (25.0%). Four patients (1.3%) had interstitial lung disease and one patient (0.3%) had infusion reactions. Encouraging antitumor activity was observed. The authors conclude that YL2-1 demonstrated an acceptable safety profile and promising efficacy in heavily pretreated patients with advanced solid tumors.