Treatment With PD-1/PD-L1 Inhibitors for Kaposi Sarcoma: A Systematic Review and Meta-Analysis

Summary: Kaposi Sarcoma (KS) is an angioproliferative tumor induced by human gammaherpesvirus 8 (HHV-8). For years, cytotoxic chemotherapy was the primary treatment for advanced KS, despite high toxicity and limited efficacy. Immunotherapy, particularly PD-1/PD-L1 inhibitors, has emerged as a promising option with antitumor activity and a favorable safety profile. We conducted a meta-analysis to evaluate its efficacy and safety in KS. A systematic search in Medline, Embase, Cochrane Library, and Web of Science identified single-arm trials on PD-1/PD-L1 inhibitors in KS. Outcomes were expressed as proportions with 95% CIs, heterogeneity assessed using I ², and significance set at P <0.05. Analyses were performed in RStudio 4.4.1. Five studies with 91 patients were included. Prior treatments included chemotherapy (35.0%), radiotherapy (22.3%), and interferon (9.2%). The pooled objective response rate (ORR) was 61% (95% CI: 49–72; I ²=16%), with 17% achieving complete response (CR) (95% CI: 8–31; I ²=0%), and the disease control rate (DCR) was 91% (95% CI: 81–96; I ²=0%). The most frequent adverse events (AEs) were pruritus (42%; 95% CI: 16–73; I ²=74%), fatigue (27%; 95% CI: 8–60; I ²=67%), and arthralgia (14%; 95% CI: 5–37; I ²=60%). This meta-analysis supports the antitumor activity of PD-1/PD-L1 inhibitors in KS. Despite high AE rates, most were clinically manageable.