9022 Background: Ipilimumab is a fully human monoclonal antibody targeting cytotoxic T-lymphocyte antigen-4 (CTLA-4) that gave durable complete/partial responses [CR/PR] and stable disease [SD]) in previously treated patients with advanced melanoma. The current study evaluated the safety and efficacy of ipilimumab and whether adding dacarbazine (DTIC) would improve outcome. In addition to being cytotoxic, DTIC may also increase the release of tumor neo-antigen, ie, act as an immunosupportive (Peggs et al. Cancer Cell.12:192, 2007) agent. Methods: Chemotherapy-naive patients with advanced melanoma were treated in the randomized, phase II, comparative, multicenter, open-label study MDX-010–08 (first patient, first visit September 2002; last patient, last visit August 2004). Patients received 3 mg/kg ipilimumab every 4 weeks (Q4W) X 4 alone or with up to six 5-day courses of DTIC 250 mg/m2 per day. Efficacy was determined using Response Evaluation Criteria for Solid Tumors. Overall survival data was collecte...