Phase 1b/2 trial of fruquintinib plus sintilimab in treating advanced solid tumours: The dose-escalation and metastatic colorectal cancer cohort in the dose-expansion phases

Background: Fruquintinib (anti-vascular endothelial growth factor 1/2/3) plus sin-tilimab (anti-programmed death-1) demonstrated enhanced anti-tumour effects versus mono -therapy in a preclinical study. We investigated the combination in patients with advanced solid tumours, including metastatic colorectal cancer (mCRC). Methods: In this phase 1b/2, open-label, multi-centre, multi-cohort dose-escalation and dose -expansion study, patients with advanced solid tumours (dose-escalation) or mCRC (one cohort in dose-expansion) received different doses of fruquintinib plus a fixed dose of sintili-mab once every 4 weeks (Q4W) or 3 weeks (Q3W). Primary objectives were safety, tolerability, and the preliminary efficacy. This study is registered at ClinicalTrials.gov, NCT03903705.Findings: By the data cut-off date (30th December 2021), 23 patients were enrolled in the dose -escalation and 37 patients in the mCRC cohort of the dose-expansion; 44 patients with mCRC