Treatment-related adverse events of combination immune checkpoint inhibitors: Systematic review and meta-analysis.

Abstract

e15060 Background: Despite increasing clinical experience with immune checkpoint inhibitors and the recent publication of clinical practice guidelines for managing treatment-related adverse events, precise and nuanced checkpoint inhibitor data in the setting of combination therapy is lacking. Herein we have conducted a systematic review and meta-analysis of treatment-related adverse event data from clinical trials evaluating combination immune checkpoint inhibitors. Methods: Studies published in PubMed, Embase, and Cochrane Database from conception to September 28, 2019 were included in the meta-analysis. Studies were eligible for inclusion if combination immune checkpoint inhibitor therapy was evaluated in advanced unresectable cancer and treatment-related adverse event data were available. For comparison of severity of adverse events in combination versus monotherapy, only the studies containing monotherapy arms as a control population were included, while all were included for calculation of pooled incidence of selected adverse events. Pooled risk ratio (RR) was used for the comparison of combination versus monotherapy and the logit transformed proportion for calculation of pooled incidence. Between-study risk of bias was evaluated using the Begg's funnel plot and Egger's regression test. Subgroup analysis was conducted by combination regimen, cancer type, and dosing regimen. Results: A total of 18 studies comprising 2767 patients across 10 cancer types were included in the final analysis. Combination ICI was associated with a slightly higher risk of all-grade adverse events (RR 1.07 [95% CI 1.03-1.11]) and markedly greater risk of grade 3 or higher adverse events (RR 2.21 [95% CI 1.57-3.10]) compared to monotherapy ICI. Subgroup analyses showed significant differences in risk of grade 3 or higher adverse events between treatment type (PD-1+CTLA-4 and PD-L1+CTLA-4), among cancer types, and among dosing regimens (N1I3, N3I1 and D20T1). Incidence of all-grade adverse events was 0.905 [95% CI 0.842-0.945] and grade 3 or higher events/all-grade adverse events was 0.396 [95% CI 0.315-0.483]. The most common all-grade TRAEs were diarrhea/colitis, fatigue/asthenia, nausea/vomiting, rash, and pruritis. Conclusions: Combination ICI therapy has a significantly different treatment-related adverse event profile compared to monotherapy.