Agnostic evaluation of ipilimumab and nivolumab association: a metanalysis

Background: Ipilimumab and Nivolumab, targeting the molecules CTLA-4, PD-1, respectively,have shown efficacy against several types of cancer. Despite these results, only a small percentage of patients maintains a long-lasting effect. Even Ipilimumab, in combination with nivolumab, has demonstrated a significant clinical benefit in multiple tumor types. However, no trial has been designed with the primary endpoint to compare the efficacy of nivolumab plus ipilimumab combined, compared to nivolumab alone. Hence, the added value of ipilimumab in the combination has not clearly been established yet. The aim of this study was to demonstrate the superiority of the combination strategy compared to the single agent therapy. Materials and methods: We performed a meta-analysis of Phase I-II-III Clinical Trials, published from 2010 up to 2020, in which the combination of ipilimumab plus nivolumab was compared to nivolumab alone. We extracted ORR, OS and PFS HR on the basis of treatment from the subgroup analysis of each trial. Results: A total of 7 trials were included in the present meta-analysis. Overall, 1313 patients were treated with the nivolumab plus ipilimumab combination compared to 1110 patients treated with nivolumabalone. All trials reported the Objective response rate(ORR), no heterogeneity was found among studies and the pooled Odds Ratio was highly in favor of the nivolumab plus ipilimumab combination with respect to nivolumab alone (1.683; 95% CI: 1.407-2.012; P < 0.0001). Three studies were considered for Progression free survival (PFS) analysis, and the pooled Hazard Ratio favored the combination of nivolumab plus ipilimumab with respect to nivolumab alone (0.807; 95% CI: 0.719-0.907; P < 0.0001). The Overall survival(OS) endpoint was considered only in 2 trials, and the pooled HR favored, also in this case, the combination of nivolumab plus ipilimumab with respect to nivolumab alone (0.87; 95% CI: 0.763-0.997; P = 0.045).