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 χ(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). Conclusions: The incidence of ipilimumab-related SAEs was higher in melanoma, the 10mg/kg group and during combination therapy. Clinicians should enhance awareness of these risk factors in clinical practice and carefully monitor patients.