PD-1 inhibitors for cutaneous squamous cell carcinoma: A meta-analysis

PD-1 inhibitors are immunotherapeutic agents used in the treatment of advanced cutaneous squamous cell carcinoma (cSCC). This study aimed to determine the pooled objective response and disease control rates of patients with advanced cSCC treated with PD-1 inhibitors. Pubmed, Cochrane Library and EMBASE databases were searched up to 1 January 2021 to include eligible articles. Objective response rate (ORR) and disease control rate (DCR) were pooled and analysed. Subgroup analysis of the odds ratio (OR) for ORR for patients by PD-L1 tumour proportion score (TPS) was performed. Seven articles including a total of 453 patients were identified and included. Pooled estimate of ORR was 44% (95% CI: 39-49%, I²  = 23.7%) and of DCR was 66% (95% CI: 57-74%, I²  = 68.2%). Pooled odds ratio of ORR for patients by PD-L1 TPS was 2.81 (95% CI: 1.22-6.51, I²  = 0.0%). These results were derived from single-arm studies, some of which were retrospective. No head-to-head trials comparing PD-1 inhibitors have been reported. We present aggregate estimates of ORR and DCR for patients with advanced cSCC treated with PD-1 inhibitors, as well as subgroup analysis for ORR for patients by PD-L1 TPS.