Pepinemab in Combination With Pembrolizumab in Recurrent or Metastatic Squamous Cell Carcinoma of the Head and Neck

The purpose of the study is to evaluate the safety and tolerability of pepinemab in combination with pembrolizumab as first-line treatment and determine a recommended Phase 2 dose (RP2D) in patients with recurrent or metastatic head and neck squamous cell carcinoma (R/M HNSCC). The study will consist of a safety run in phase and a dose expansion phase. The primary objective of the Safety Run-in phase of the study is to evaluate the safety and tolerability of pepinemab in combination with pembrolizumab as first-line treatment and determine a recommended Phase 2 dose (RP2D) for the dose-expansion phase enrolling subjects in patients with recurrent or metastatic head and neck squamous cell carcinoma (R/M HNSCC). The primary objective of the Dose Expansion phase of the study is to evaluate objective response rate (ORR) per Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 of the combination of pepinemab/pembrolizumab in immunotherapy naïve patients with R/M HNSCC. The secondary objectives of the study are to evaluate progression-free survival (PFS) by RECIST 1.1 of the combination of pepinemab/pembrolizumab in immunotherapy naïve patients with R/M HNSCC, to evaluate the overall survival (OS), and to evaluate the duration of response (DOR). The exploratory objectives of the study are to evaluate PFS, ORR, and DOR via the iRECIST criteria, to evaluate the pharmacokinetics (PK), pharmacodynamics (PD), and immunogenicity of the combination, to investigate the relationship between treatment with pepinemab and pembrolizumab and certain biomarkers and the genomic signatures of baseline or archival tumor samples. The Safety Run-in phase will enroll a minimum of 3 subject and a maximum of 18 subjects who will be treated with intravenous pepinemab IV (starting at 20 mg/kg, with potential dose modifications to 15 mg/kg or 10 mg/kg) and pembrolizumab at 200 mg IV, Q3W. The Dose Expansion phase of the study will enroll a maximum of approximately 62 subjects who will be treated with intravenous pepinemab administered IV at the RP2D, plus pembrolizumab 200 mg IV, Q3W. Subjects will undergo evaluation for extent of disease (EOD) at baseline, week 9, every 6 weeks through year 1, and every 9 weeks thereafter. Subjects who discontinue study treatment will continue to be followed for survival every 12 weeks after safety follow-up (for up to approximately 2 years).