Up to 150 patients will be included in this study. Up to 30 DLT evaluable patients will be enrolled in phase 1a (dose escalation), 40 per-protocol treated patients in phase 1b (dose expansion), and 80 per-protocol treated patients in phase 2.~Phase 1a uses the Bayesian optimal interval (BOIN) design, to investigate the safety and determine the MTD of HLX301. BOIN design combines rule-based and model-based design, allowing for flexibility of dose escalation and de-escalation, and high patient enrollment in doses closest to the target toxicity rate (pre-defined as 30% in this study). This study will also evaluate safety profiles at different dose levels, PK parameters, pharmacodynamic markers, immunogenicity, and the preliminary efficacy of the drug.~Following dose escalation and determination of the MTD, additional patients with NSCLC will be enrolled in phase 1b dose expansion to further evaluate PK and pharmacodynamic characteristics, and preliminary efficacy in order to determine the RP2D.~The phase 2 clinical expansion will include patients with various cancer types, including:~20 per-protocol treated patients with non-small cell lung cancer (NSCLC) 20 per-protocol treated patients with gastric/esophagogastric junction adenocarcinoma (GC/EGJ) 20 per-protocol treated patients with head and neck squamous cell carcinoma (HNSCC) 20 per-protocol treated patients with urothelial carcinoma (UC)
This Phase 1/2, multicenter, first-in-human, open-label, dose-escalation, dose expansion, and clinical expansion study will evaluate the safety, tolerability, pharmacokinetics, and preliminary anti-tumor efficacy of HLX301 administered as a single-agent by IV infusion every 2 weeks to patients with locally advanced or metastatic solid malignancies, who have failed or are intolerant to standard therapy, or for whom no standard therapy is available. This study has three parts: phase 1a dose escalation, phase 1b dose expansion, and phase 2 clinical expansion.