CAMRESBRT: Randomized Phase II Trial of Camrelizumab with Stereotactic Body Radiotherapy vs. Camrelizumab Alone in Recurrent or Metastatic Head and Neck Squamous Cell Carcinoma

Purpose/Objective(s) Immune checkpoint inhibitor (ICI) therapy has significantly expanded the therapeutic armamentarium for recurrent or metastatic (R/M) head and neck squamous cell carcinoma (HNSCC). Radiation stimulation of abscopal responses, combined with ICI, has been examined in single-arm trials with various tumor types, but randomized evaluation of nivolumab with stereotactic body radiotherapy (SBRT) in R/M HNSCC was frustrated. We aimed to test whether anti–PD-1 therapy, Camrelizumab, may act synergistically with SBRT to improve response through the abscopal effect. Materials/Methods We conducted a single-center, randomized, phase II trial. Patients older than 18 years of age with R/M HNSCC who have not been treated with ICIs, regardless of PD-L1 status, are eligible for this study. This trial planned to enroll approximately 70 patients. Patients were randomly assigned (1:1), stratified by human papillomavirus status and PD-L1 status, to camrelizumab versus camrelizumab plus SBRT. Patients have at least two metastatic lesions: one that could be safely irradiated and one measurable by RECIST version 1.1. Drug: camrelizumab (200mg intravenously every 2 weeks). Radiation: SBRT (27 Gy over 3 fractions given every other day) to single lesion to start by study day (study day 1 is day of first dose of camrelizumab). The primary end point was objective response rate (ORR) in nonirradiated lesions, which was assessed by RECIST 1.1. The secondary objectives were safety and tolerability (adverse events of grade 3-4 or higher, rate of long-term adverse events), 6-month and 1-year disease control rate (DCR), 6-month and 1-year progression free survival (PFS), overall survival (OS). Results As of January 2022, 31.4% of the planned 70 subjects have been enrolled. Median age was 54.5 years; 17 patients were male. 14 patients received camrelizumab alone and 8 patients received camrelizumab plus SBRT. The PD-L1 status was known in 14 of 18 patients, including 1 patient with PD-L1 CPS (combined positive score) less than 1, 3 patients more than 20, and 10 patients between 1-20. ClinicalTrials.gov Identifier: NCT04830267. Conclusion Clinical trial in progress.