First-in-Human Phase I Study of Lumretuzumab, a Glycoengineered Humanized Anti-HER3 Monoclonal Antibody, in Patients with Metastatic or Advanced HER3-Positive Solid Tumors

Abstract Purpose: A first-in-human phase I study was conducted to characterize safety, efficacy, and pharmacokinetic (PK) and pharmacodynamic (PD) properties of lumretuzumab, a humanized and glycoengineered anti-HER3 monoclonal antibody, in patients with advanced cancer. Experimental Design: Twenty-five patients with histologically confirmed HER3-expressing tumors received lumretuzumab (100, 200, 400, 800, 1,600, and 2,000 mg) every two weeks (q2w) in 3+3 dose-escalation phase. In addition, 22 patients were enrolled into an extension cohort at 2,000 mg q2w. Results: There were no dose-limiting toxicities. Common adverse events (any grade) included diarrhea (22 patients, 46.8%), fatigue (21 …