Hodi 2010a.

Study characteristics
Methods	Phase III parallel‐group RCT. Double‐blind study
Participants	HLA‐A*0201–positive metastatic melanoma which had progressed during systemic treatment . Participants randomised: 676.
Interventions	Three‐arm trial: Ipilimumab 3 mg/kg + gp100 peptide vaccine every 3 weeks for 4 treatments (N = 403); Ipilimumab 3 mg/kg every 3 weeks for 4 treatments (N = 137); gp100 peptide vaccine for four treatments (N = 136).
Outcomes	Overall survival. Progression‐free survival. Tumour response. Toxicity.
Notes	Cross‐over: not allowed. Quality of life: Ipilimumab did not have a detrimental effect on QoL during the treatment induction phase (Revicki 2012). Participants with brain metastasis: participants with active, untreated metastases in the central nervous were excluded. Median follow‐up: 21 months.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "Patients were randomly assigned". Comment: Risk was likely low because this was a multicentre trial with centralised randomisation.
Allocation concealment (selection bias)	Low risk	Risk was likely low because this was a multicentre trial with centralised randomisation.
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Quote: “Double‐blind”. Comment: This method ensured low risk of performance bias.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Quote: “Double‐blind”. Comment: This method ensured low risk of detection bias.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Missing outcome data were balanced across intervention groups, with similar reasons for missing data across groups.
Selective reporting (reporting bias)	Low risk	No differences between protocol and published report.
Other bias	Low risk	The study appeared to be free of other sources of bias.