Efficacy and safety of immune checkpoint inhibitors in recurrent or metastatic head and neck squamous cell carcinoma: A systematic review and meta‐analysis of randomized clinical trials

Abstract Background Immune checkpoint inhibitors (ICIs) showed antitumor activity for recurrent or metastatic head and neck squamous cell carcinoma (R/M HNSCC). However, the results from different studies were controversial. Methods Online databases were searched for randomized clinical trials (RCTs) evaluating ICIs for R/M HNSCC. The characteristics of the studies and the results of overall survival (OS), progression‐free survival (PFS), objective response rate (ORR), treatment‐related adverse events (TRAEs) were extracted. Results A total of 4936 patients from eight studies were included. Anti‐PD1/PDL1 monotherapy significantly improved OS in total population (hazard ratio, HR, 0.87, 95% CI, 0.79–0.95, p = 0.003) and PD‐L1 high expression patients (HR, 0.71, 95% CI, 0.55–0.90, p = 0.006) with significant lower incidence of any grade TRAEs (odds ratio, OR, 0.16, 95% CI, 0.07–0.37, p