During the Induction Period, participants received ipilimumab, 10 mg/kg, as tolerated by intravenous (IV) infusion as 1 single dose during Weeks 1 (Day 1), 4, 7, and 10 for a total of 4 separate doses. During the Maintenance Phase, participants received ipilimumab, 10 mg/kg, as tolerated by IV infusion every 12 weeks, beginning at Week 24, until disease progression or unacceptable toxicity occurred or the patient withdrew consent. Participants also received dacarbazine, 850 mg/m^2, by IV infusion over 30 to 60 minutes, starting on Week 1 and repeated every 3 weeks until Week 22. Dacarbazine was dosed on the same day as ipilimumab, when applicable, after the ipilimumab dose.

Survival rate=percentage of participants surviving at 1 year following start of study drug. Every effort was made to collect survival data on all patients, including those withdrawn from treatment for any reason. If the death of a patient was not reported, the patient's last known alive date was recorded. Confidence intervals were computed using the Clopper-Pearson method.

irAEs are adverse events of unknown cause, consistent with an immune phenomenon, and considered to be causally related to drug exposure. Six subcategories of irAE are assessed: gastrointestinal, liver, skin, endocrine, neurologic, and other. The irAEs are programmatically determined from a predefined list of MedDRA terms. irAEs will be measured every 3 weeks in induction phase, every 6 weeks in Maintenance Phase to Week 48, and every 12 weeks until Progressive Disease. Grading criteria: Grade 1=Mild, Grade 2=Moderate, Grade 3=Severe, Grade 4=Life-threatening or disabling, Grade 5=Death.

During the Induction Period, participants received ipilimumab, 10 mg/kg, as tolerated by intravenous (IV) infusion as 1 single dose during Weeks 1 (Day 1), 4, 7, and 10 for a total of 4 separate doses. During the Maintenance Phase, participants received ipilimumab, 10 mg/kg, as tolerated by IV infusion every 12 weeks, beginning at Week 24, until disease progression or unacceptable toxicity occurred or the patient withdrew consent. Participants also received dacarbazine, 850 mg/m^2, by IV infusion over 30 to 60 minutes, starting on Week 1 and repeated every 3 weeks until Week 22. Dacarbazine was dosed on the same day as ipilimumab, when applicable, after the ipilimumab dose.

Survival rate=percentage of participants surviving at 1 year following start of study drug. Every effort was made to collect survival data on all patients, including those withdrawn from treatment for any reason. If the death of a patient was not reported, the patient's last known alive date was recorded. Confidence intervals were computed using the Clopper-Pearson method.

All participants who received at least 1 dose of study drug.

During the Induction Period, participants received ipilimumab, 10 mg/kg, as tolerated by intravenous (IV) infusion as 1 single dose during Weeks 1 (Day 1), 4, 7, and 10 for a total of 4 separate doses. During the Maintenance Phase, participants received ipilimumab, 10 mg/kg, as tolerated by IV infusion every 12 weeks, beginning at Week 24, until disease progression or unacceptable toxicity occurred or the patient withdrew consent. Participants also received dacarbazine, 850 mg/m^2, by IV infusion over 30 to 60 minutes, starting on Week 1 and repeated every 3 weeks until Week 22. Dacarbazine was dosed on the same day as ipilimumab, when applicable, after the ipilimumab dose.