Incidence of Ipilimumab-Related Serious Adverse Events in Patients with Advanced Cancer: A Meta-Analysis

Background: Little is known about the incidence of ipilimumab-related serious adverse events (SAEs) across various tumor types, drug doses and treatment regimens. Methods: PubMed database was searched up to November, 2017 to identify prospective clinical trials of ipilimumab therapy for adult patients with cancer. Comparisons of the incidence were based on the 2 test in univariate analysis and the logistic regression model in multivariate analysis. Results: Twenty-four studies (4549 patients) with 35 independent study cohorts (21 melanoma, 6 prostate cancer, 5 NSCLC, and 3 SCLC cohorts) of ipilimumab were included in the meta-analysis. The overall incidence of SAEs during ipilimumab mono-therapy was 26.1% (95% CI, 21.1%-31.8%). SAEs were more frequent in the 10 mg/kg groups than in the 3 mg/kg groups (35.9% vs 17.3%; P < 0.001). Combination therapy showed significantly higher incidence than mono-therapy in melanoma (33.8% vs 25.0%; P = 0.002). After adjustment for potential confounders, multivariable analyses demonstrated lower odds of SAEs in NSCLC (odds ratio [OR] 0.52, 95% CI 0.40-0.69, P < 0.001) and SCLC (OR 0.41, 95% CI 0.31-0.54, P < 0.001) compared with melanoma. The 10mg/kg cohort presented significantly higher odds than the 3mg/kg (OR 2.84, 95% CI 2.35-3.43, P < 0.001). The combination therapy showed significantly higher odds than the mono-therapy (OR 1.38, 95% CI 1.11-1.71, P = 0.003).