Effects of Pembrolizumab in Recurrent/Metastatic Squamous Cell Head and Neck Carcinoma: A Multicenter Retrospective Study.

BACKGROUND/AIM:Pembrolizumab exhibits anticancer efficacy in platinum-sensitive or platinum-unfit patients with recurrent/metastatic squamous cell carcinoma of the head and neck (R/M SCCHN). However, no large-scale retrospective real-world data are available. This retrospective study aimed to examine the efficacy and safety of pembrolizumab in multiple facilities. PATIENTS AND METHODS:Data of 167 patients with R/M SCCHN treated with pembrolizumab between December 2019 and February 2022 were analyzed. The endpoint was overall survival (OS), progression-free survival (PFS), and immune-related adverse events (irAEs). OS and PFS were analyzed comparatively with and without irAEs, and complete response (CR) or partial response (PR), and stable disease (SD) or progressive disease (PD) were compared. RESULTS:One hundred thirty-five patients received pembrolizumab alone, whereas the others received pembrolizumab with chemotherapy. For the pembrolizumab only group, the median OS and PFS were 22.7 and 5.1 months, respectively. There were significant differences in OS and PFS between CR or PR and SD or PD (p<0.01, p<0.01, respectively). For pembrolizumab with chemotherapy, the OS was not reached and median PFS was 7.0 months. There was a significant difference in PFS between CR or PR and SD or PD (p<0.01). There was a significant difference in PFS between patients with and without irAEs (p=0.02). CONCLUSION:The real-world therapeutic effect of pembrolizumab for R/M SCCHN was comparable to that observed in the KEYNOTE048 trial. In addition, irAEs and best overall response were considered as prognostic factors.