Evaluation of the effect of systemic corticosteroids for the treatment of immune-related adverse events (irAEs) on the development or maintenance of ipilimumab clinical activity

9037 Background: Ipilimumab, a fully human monoclonal antibody that inhibits cytotoxic T-lymphocyte antigen-4, has clinical activity at 10 mg/kg in patients (pts) with advanced melanoma. Most grade 3/4 immune-related adverse events (irAEs) associated with ipilimumab can be managed with systemic corticosteroids following established treatment guidelines. However, little has been reported about the effects of corticosteroids used to treat irAEs on ipilimumab antitumor responses. Methods: Across 3 phase II studies with 10 mg/kg ipilimumab monotherapy in advanced melanoma (CA184008, 022, and 007; N=283), 83 pts (29.3%) achieved disease control [complete/partial responses (CR/PR), or stable disease (SD) ≥12 weeks] and 43/83 (52%) received steroids for treatment of irAEs. The pts' ability to develop and maintain disease control in the presence and absence of steroids was analyzed. Disease control was assessed by modified World Health Organization (mWHO) criteria and novel immune-related response criteria (irRC)...