Efficacy and Safety of Iparomlimab, an Anti-PD-1 Antibody, in Patients with Advanced Solid Tumors: A Phase 1c Study

Abstract

Introduction: Iparomlimab (QL1604) is a humanized immunoglobulin G4 mAb against programmed cell death protein 1 (PD-1). Here, we report the preliminary efficacy, safety, pharmacokinetics, and immunogenicity of iparomlimab in patients with advanced solid tumors.

Methods: In this open-label, phase 1c study, patients with advanced or metastatic solid tumors, either failed or had no standard therapies available, were enrolled and received intravenous iparomlimab at 3 mg/kg once every 3 weeks. The primary efficacy endpoint was the objective response rate (ORR) assessed by the investigator per Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1.

Results: Between July 20, 2020, and September 6, 2021, 71 patients were enrolled and received at least one dose of iparomlimab. The ORR was 9.9% (7/71) and disease control rate was 36.6% (26/71). Median duration of response of all responders was 10.7 months [95% confidence interval (CI), 1.4-not estimable]. Additionally, the median time to progression, progression-free survival, and overall survival were 1.4 months (95% CI, 1.4-2.8), 1.4 months (95% CI, 1.4-2.7), and 9.7 months (95% CI, 7.2-15.3), respectively. A total of 52 (73.2%) patients experienced treatment-related adverse events (TRAEs) (grade ≥ 3, 19.7%). The most common TRAE (≥ 10%) was anemia (18.3%). A total of 20 (28.2%) experienced immune-related adverse events (grade ≥ 3, 7.0%). TRAEs leading to discontinuation of study drug occurred in 4 (5.6%) patients, including immune-mediated myocarditis (2 patients), Guillain-Barré syndrome (1 patient), and diarrhea (1 patient).

Conclusions: Iparomlimab showed preliminary clinical activity and had a manageable safety profile in patients with advanced solid tumors. These results support further investigation of iparomlimab as monotherapy or in combination therapy in advanced solid tumors.

Trial registration: ClinicalTrials.gov identifier, NCT05801094. Retrospectively registered in 2023-03-24.

Keywords: Advanced solid tumors; Efficacy; Iparomlimab; Phase 1c; Programmed cell death 1.