Table 1. Characteristics of included trials.

Study	N	Stage	Previous treatment	Interventions	Jadad Score
					Randomization	Blinding	Follow-up
Therapeutic vaccines
Neninger VE 2008	80	IIIB–IV	Four to six cycles of platinum-based chemotherapy	EGF vaccine vs. BSC	2	0	1
Manegold C 2008	112	IIIB–IV	Chemotherapy-naive	Chemotherapy + PF-3512676 vs. chemotherapy	1	0	1
Butts, C 2011	171	IIIB–IV	Stable disease or an objective clinical response after first-line treatment	BLP-25 + BSC vs. BSC	1	0	1
Quoix E 2011	148	IIIB–IV	Absence of systemic therapy	TG4010 + GC vs. GC	2	0	1
Mikhail S 2013	121	IIIB–IV	One chemotherapy regimen	Bavituximab + D vs. P + D	1	1	0
Butts C 2014	1239	IIIA–IIIB	≥2 chemotherapy regimens	BLP-25 vs. P	2	1	1
Alfonso S 2014	176	IIIB–IV	Achieved CR, PR, or SD after the standard first-line therapy	Racotumomab vs. P	1	1	1
Giaccone G 2015	532	IIIA–IV	Stable disease or response following first-line treatment	Belagenpumatucel-L vs. P	2	1	1
Quoix E 2015	222	IV	Untreated before	TG4010 + CP vs. P + CP	1	1	0
Immune checkpoint inhibitors
Lynch TJ 2012	204	IIIB–IV	Absence of systemic therapy	Ipilimumab + CP vs. P + CP	1	1	1
Brahmer J 2015	272	IIIB–IV	Recurrence after one prior platinum-containing regimen	Nivolumab vs. D	2	0	1
Borghaei H 2015	582	IIIB–IV	Recurrence after resection or progression after one prior platinum-based chemotherapy	Nivolumab vs. D	2	0	1
Alexander I 2015	287	IIIB–IV	Recurrence or progression after one prior platinum-containing regimen	MPDL3280A vs. D	1	0	0
Other immunomodulators and cellular therapy
O’Brien 2004	419	IIIA–IV	Chemotherapy-naive	MVP + SRL172 vs. MVP	2	0	1
Digumarti R 2011	110	IIIB–IV	Absence of systemic therapy	TLF + CP vs. CP + P	1	1	1
Ridolfi L 2011	239	IIIB–IV	Untreated before	IL-2 + GC vs. GC	1	0	1
Parikh PM 2011	100	IIIB–IV	≥1 chemotherapy regimens	TLF + BSC vs. BSC + P	2	1	1
Ramalingam S 2013	742	IIIB–IV	≥2 chemotherapy regimens	TLF + BSC vs. BSC + P	2	1	1
Zhong Runbo 2011	28	IIIB–IV	Untreated before	DC/CIK + NP vs. NP	1	0	1
Wu Changping 2008	59	IIIA–IV	Taxanes naive	CIK + TP vs. TP	1	0	1

NP: vinorelbine with platinum chemotherapy; TP: docetaxel 75 mg/m², day 1; cisplatin, 25 mg/m², days 1–4, tri-weekly; CP: carboplatin plus paclitaxel;

GC: cisplatin plus gemcitabine; D: docetaxel; MVP: mitomycin, vinblastine and cisplatin or carboplatin; TLF: talactoferrin; P: placebo.