Table 1.

Baseline characteristics of included studies comparing immune checkpoint inhibitors to non immune checkpoint inhibitors.

Study	Study type	Treatment arms	Indication	All-grade (grades 1–4) pneumonitis	High-grade (grades 3–4) pneumonitis
1. Ipilimumab studies
Kwon et al. [2014]	Phase III	Arm A: ipilimumab 10 mg/kg (393 pts) Arm B: placebo (396 pts)	Metastatic castration-resistant prostate cancer	5 (1.3%) versus 0	1 (0.3%) versus 0
2. Nivolumab studies
Robert et al. [2015a]	Phase III	Arm A: nivolumab 3 mg/kg of body weight every 2 weeks (206 pts) Arm B: dacarbazine (205 pts)	Stage III or IV unresectable melanoma without a BRAF mutation.	3 (1.5%) versus 0	0 versus 0
Weber et al. [2015]	Phase III	Arm A: nivolumab 3 mg/kg of body weight every 2 weeks (268 pts) Arm B: investigator choice chemotherapy (102 pts)	Patients with advanced melanoma who progressed after anti-CTLA-4 treatment	5 (1.9%) versus 0	0 versus 0
Brahmer et al. [2015]	Phase III	Arm A: nivolumab 3 mg/kg of body weight every 2 weeks (131 pts) Arm B: docetaxel (129 pts)	Advanced squamous cell NSCLC	6 (5%) versus 0	0 versus 0
Borghaei et al. [2015]	Phase III	Arm A: nivolumab 3 mg/kg of body weight every 2 weeks (292 pts) Arm B: docetaxel (290 pts)	Advanced non squamous cell NSCLC	8 (3%) versus 1 (<1%)	3 (1%) versus 1 (<1%)
Motzer et al. [2015]	Phase III	821 patients were randomly assigned (in a 1:1 ratio) to receive 3 mg of nivolumab per kilogram of body weight intravenously every 2 weeks or a 10 mg everolimus tablet orally once daily	Advanced clear-cell renal cell carcinoma for which they had received previous treatment with one or two regimens of antiangiogenic therapy	16 (4%) versus 58 (15%)	6 (1%) versus 11 (3%)
3. Pembrolizumab studies
Ribas et al. [2015]	Randomized phase II	Arm A: pembrolizumab (low dose 2 mg/kg): 179 pts Arm B: pembrolizumab (high dose 10 mg/kg):178 pts Arm C: chemotherapy control: 171 pts	Ipilimumab-refractory advanced melanoma	3 (2%) versus 3(2%) versus 0	0 versus 2(1%) versus 0
Herbst et al. [2015]	Randomized phase II/III study	Arm A: pembrolizumab (low dose 2 mg/kg): 344 pts Arm B: pembrolizumab (high dose3 mg/kg ):346 pts Arm C: Docetaxel: 343 pts	Previously treated NSCLC with PD-L1>1%	16 (5%) versus 15 (4%) versus 6 (2%)	7 (2%) versus 7 (2%) versus 2 (1%)

CTLA-4, cytotoxic T lymphocyte antigen-4; NSCLC, non-small cell lung cancer; PD-L1, programmed death ligand 1; pts, patients.