PD-1/PD-L1 inhibitor monotherapy in recurrent or metastatic squamous cell carcinoma of the head and neck: a meta-analysis

Purpose: To evaluate the efficacy and safety of programmed cell death-1/programmed cell deathligand 1 inhibitor monotherapy compared to the standard of care in the first-line setting for recurrent or metastatic head and neck squamous cell carcinoma. Materials and methods: The PubMed, Embase, and Cochrane Library databases were searched for relevant ran-domized controlled trials. The clinical outcomes of overall survival, progression-free survival, objective response rates, and grade 3 or higher adverse events were analyzed using Stata SE 15 software with a significance level set to 0.05. Results: We identified four randomized controlled trials (1 nivolumab, 2 pembrolizumab, and 1 durvalumab), including a total of 2474 patients. The results of the meta-analysis showed pooled hazard ratios of overall and progression-free survival for programmed cell death-1/programmed cell death-ligand 1 inhibitor monotherapy of 0.82 (95% CI: 0.73-0.91, p < 0.001) and 0.96 (95%CI: 0.84-1.07, p < 0.001) and pooled odds ratios of objective response rates and grade 3 or higher adverse events of 1.04 (95%CI: 0.46-2.37; p = 0.926) and 0.28 (95%CI: 0.22-0.35, p < 0.001), respectively. Subgroup analysis showed that inhibitors for both programmed cell death-1 (nivolumab and pembrolizumab) and programmed cell death-ligand 1 (durvalumab) were associated with significantly longer overall survival (HR = 0.80, 95% CI: 0.70-0.90, p < 0.001 and HR = 0.88, 95%CI: 0.70-1.06, p < 0.001, respectively). Conclusions: Programmed cell death-1/programmed cell deathligand 1 inhibitor monotherapy showed more clinical benefit versus the standard of care in patients with recurrent or metastatic head and neck squamous cell carcinoma, with an acceptable safety profile.