Ipilimumab versus placebo after complete resection of stage III melanoma: Initial efficacy and safety results from the EORTC 18071 phase III trial.

LBA9008 Background: Ipilimumab (Ipi), a fully human monoclonal antibody that blocks cytotoxic T-lymphocyte antigen-4 to augment antitumor immune responses, is an approved treatment for advanced melanoma. Here, we report the results of a phase III trial designed to evaluate Ipi as an adjuvant therapy for resected stage III melanoma at high risk of recurrence. Methods: In this randomized, double-blind trial, eligible patients (pts) included those ≥18 yrs of age who underwent complete resection of stage III cutaneous melanoma (excluding lymph node metastasis ≤1 mm or in-transit metastasis). 951 pts were randomized (stratified by stage and region) 1:1 to receive Ipi 10 mg/kg (n=475) or placebo (Pbo, n=476) every 3 wks for 4 doses, then every 3 mos for up to 3 yrs until completion, disease recurrence, or unacceptable toxicity. The primary endpoint was recurrence-free survival (RFS), analyzed on the intent-to-treat population. 512 RFS events (recurrence or death) were needed to provide 90% power to detect an Ip...