TQB2450 in patients with advanced malignant tumors: results from a phase I dose-escalation and expansion study

Background:Immune checkpoint inhibitor therapy has demonstrated impressive clinical benefits in multiple tumor types. TQB2450, a novel monoclonal antibody targeting programmed cell death ligand 1, has shown safety and efficacy in preclinical studies.Objectives:This first-in-human study aimed to evaluate the safety/tolerability, pharmacokinetics (PK), immunogenicity, and preliminary antitumor activity of TQB2450 in patients with advanced malignant tumors.Design and methods:In this phase I study, eligible patients with advanced malignant tumors received intravenous TQB2450 once every 3 weeks. This study consisted of a 3 + 3 dose-escalation phase (1-30 mg/kg) and a specific dose-expansion phase (1200 mg). The primary endpoints were maximum tolerated dose (MTD), dose-limiting toxicity (DLT), and safety. The secondary endpoints were PK, immunogenicity, and investigator-assessed response rate.Results:Between April 2018 and February 2020, 40 patients were enrolled (22 in the dose-escalation phase and 18 in the dose-expansion phase). No DLT was reported and the MTD was not reached. Grade > 3 or worse treatment-related treatment-emergent adverse events (AEs) occurred in 11 (27.50%) patients, with the most frequent being aspartate aminotransferase increased (5.00%), leukopenia (5.00%), and anemia (5.00%). Treatment-related serious AEs were reported in six patients, the most common of which was decompensated liver function (5.00%). No treatment-related death was reported. The maximum serum concentration of TQB2450 increased in a dose-proportional manner. Treatment-induced anti-drug antibodies were detected in 31.58% (12/38) of patients. The investigator assessed the objective response rate as 5.00% and the disease control rate was 52.50%, including 2 partial responses and 19 stable diseases. The median progression-free survival was 2.69 (95% confidence interval, 2.07-6.14) months.Conclusion:TQB2450 has a manageable safety profile with favorable PK and immunogenicity and has shown early evidence of clinical activity in advanced malignant tumors.ClinicalTrials.gov identifier:NCT03460457.