Efficacy and Safety of the Anti–PD-L1 mAb Socazolimab for Recurrent or Metastatic Cervical Cancer: a Phase I Dose-Escalation and Expansion Study

PURPOSE: This study (ClinicalTrials.gov identifier, NCT03676959) is an open, phase I dose-escalation and expansion study investigating the safety and efficacy of the recombinant, fully human anti-programmed death ligand 1 (PD-L1) mAb socazolimab in patients diagnosed with recurrent or metastatic cervical cancer. PATIENTS AND METHODS: Patients received socazolimab every 2 weeks until disease progression. The study was divided into a dose-escalation phase and a dose-expansion phase. Safety and tolerability were primary endpoints of the dose-escalation phase. The primary endpoints of the dose-expansion phase were safety and the objective response rate (ORR) of the 5 mg/kg dose. Efficacy was assessed by the third-party independent review committee (IRC) using the Response Evaluation Criteria in Solid Tumors version 1.1 (RECIST 1.1). RESULTS: 104 patients were successfully enrolled into the study. Twelve patients were included in the dose-escalation phase, with one complete response and two partial responses in the 5 mg/kg treatment group. Ninety-two patients (5 mg/kg) were enrolled in the dose-expansion phase. Fifty-four patients (59.3%) had baseline PD-L1-positive tumor expression (combined positive score ≥1). ORR was 15.4% [95% confidence interval (CI), 8.7%-24.5%]. Median PFS was 4.44 months (95% CI, 2.37-5.75 months), and the median OS was 14.72 months (95% CI, 9.59-NE months). ORR of PD-L1-positive patients was 16.7%, and the ORR of PD-L1-negative patients was 17.9%. No treatment-related deaths occurred. CONCLUSIONS: Our study demonstrates that socazolimab has durable safety and efficacy for the treatment of recurrent or metastatic cervical cancer and exhibits a safety profile similar to other anti-PD-1/PD-L1 mAbs.