Table 1. Descriptive summary of the included patients and randomized trials.

Study	ClinicalTrials.gov number	Recruitment period	Median duration of follow-up (months)	Median age (range)	Patient sex (M/F)	Disease stage	First-line therapy	Intervention		Overall response rate (%)		Median progression-free survival (mo.)
								PD-1 group	Control group	PD-1 group	Control group	PD-1 group	Control group
Larkin J 2015 [19]	NCT01844505	2013–2014	12.2–12.5	60(18–90)	404/227	stage III or IV	Yes	Nivolumab 3 mg/kg IV every 2 weeks	Ipilimumab 3 mg/kg every 3 weeks; 4 doses	43.7	19.0	6.9	2.9
Ribas A 2015 [17]	KEYNOTE-002	2012–2013	6–14	62(18–89)	327/213	stage III or IV	No (ipilimumab-refractory)	Pembrolizumab 2 mg/kg or 10 mg/kg IV every 3 weeks	Investigator-choice chemotherapy	23.3	4.5	3.7 (2 mg/kg group) 5.4 (10 mg/kg group)	2.6
Robert C 2015 [18]	NCT01721772	2013–2014	5.2–16.7	65(18–87)	246/172	stage III or IV	Yes	Nivolumab 3 mg/kg IV every 2 weeks	Dacarbazine 1000 mg/m2 every 3 weeks	40.0	13.9	5.1	2.2
Robert C 2015 [19]	NCT01866319	2013–2014	6.1–11.5	62(18–88)	497/337	stage III or IV	Y/N (received no more than one previous systemic therapy)	Pembrolizumab 10 mg/kg either every 2 or 3 weeks	Ipilimumab 3 mg/kg every 3 weeks; 4 doses	33.2	11.9	5.5 (2-week group) 4.6 (3-week group)	2.8
Weber J 2015 [20]	CheckMate 037	2012–2014	5.6–11.2	59(23–88)	261/144	stage IIIC or IV	No (progression after anti-CTLA4 treatment)	Nivolumab 3 mg/kg IV every 2 weeks	Investigator-choice chemotherapy	31.6	10.6	4.7	4.2