Ipilimumab With or Without Sargramostim in Treating Patients With Stage III or Stage IV Melanoma That Cannot Be Removed by Surgery

PRIMARY OBJECTIVES: I. To evaluate the overall survival for the combination of sargramostim (GM-CSF) plus ipilimumab and ipilimumab alone in patients with advanced melanoma. SECONDARY OBJECTIVES: I. To evaluate the progression-free survival, response rate, safety and tolerability for the combination of GM-CSF plus ipilimumab and ipilimumab alone in patients with advanced melanoma. II. To explore the utility of immune related response criteria (irRC) prospectively in patients receiving ipilimumab. OUTLINE: Patients are randomized to 1 of 2 treatment arms. ARM A: Patients receive induction therapy comprising ipilimumab intravenously (IV) over 90 minutes on day 1 and sargramostim subcutaneously (SC) once daily on days 1-14. Treatment repeats every 21 days for 4 cycles. After 12 weeks of induction treatment, anti-tumor response is assessed and patients then receive maintenance therapy comprising ipilimumab IV over 90 minutes on day 1 and sargramostim SC once daily on days 1-14. Treatment with ipilimumab repeats every 12 weeks and treatment with sargramostim repeats every 21 days. After 12 weeks of maintenance therapy, anti-tumor response is reassessed and patients with responsive or stable disease then continue maintenance therapy until disease progression or unacceptable toxicity. ARM B: Patients receive induction therapy comprising ipilimumab IV over 90 minutes on day 1. Treatment repeats every 21 days for 4 cycles. After 12 weeks of induction treatment, anti-tumor response is assessed and patients then receive maintenance therapy of ipilimumab IV over 90 minutes on day 1. Treatment with ipilimumab repeats every 12 weeks. After 12 weeks of maintenance therapy, anti-tumor response is reassessed and cycles repeat every 12 weeks in the absence of disease progression or unacceptable toxicity. After completion of study therapy, patients are followed up every 3 months for 2 years and then every 6 months for 3 years.