The efficacy and safety of cemiplimab in locally advanced or metastatic cutaneous squamous cell carcinoma: A comparative analysis of retrospective studies versus prospective studies

Cemiplimab has been widely recommended by international guidelines to treat patients with locally advanced or metastatic cutaneous squamous cell carcinoma (CSCC). In this study, we conducted a comparative analysis to integrate the efficacy and safety data in the published prospective and retrospective studies for better understanding the application of cemiplimab. The online databases (PubMed, Cochrane CENTRAL, Web of Science, and EMBASE) were searched to find out eligible studies from inception to November 4, 2021. The "R" software and the "meta" package were used to synthesize the objective response rates (ORRs), disease control rates (DCRs), and the incidences of treatment-related adverse events (TRAEs). Overall, three retrospective studies with 398 patients and three prospective studies with 219 patients were enrolled. The pooled ORR and DCR were 53% (95% confidence interval [CI] 46-59) and 70% (95% CI 57-82) for retrospective studies versus 45% (95% CI 39-52) and 68% (95% CI 56-79) for prospective studies. In regard of toxicities, prospective studies reported much higher incidences of any grade (99% vs. 47%) and grade 3-4 TRAEs (43% vs. 15%) against retrospective studies. The most reported TRAE was fatigue, followed by diarrhea and pruritus. In addition, nine treatment-related deaths (four in retrospective studies vs. five in prospective studies) were documented. In both retrospective and prospective clinical practices, cemiplimab could be an effective regimen for locally advanced or metastatic CSCC patients, but toxicities during the treatment deserve further attention.