Table 2.

Clinical trials of immune checkpoint blockade in EC

Target	Drug	Treatment	Phase	Study ID	Outcome summary
PD-1	Pembrolizumab	Pembrolizumab alone	IB	Keynote-028	ORR 30% in PD-L1+ EC
		Pembrolizumab alone	II	Keynote-180 (NCT02559687)	ORR 14.3% in ESCC and 5.2% in EAC
		Pembrolizumab vs. irinotecan or taxanes	III	Keynote-181 (NCT02564263)	Median OS in ESCCs: 8.2 vs. 7.1 months ORR in ESCCs: 16.7% vs. 7.4%
		Pembrolizumab + cisplatin and 5-fluorouracil vs. placebo	III	Keynote-590 (NCT03189719)	Ongoing
PD-1	Nivolumab	Nivolumab vs. taxanes	III	NCT02569242	Median OS in ESCCs: 10.9 vs. 8.4 months
		Nivolumab alone	II	JapicCTI-142422	17% of ESCC patients had a centrally assessed objective response
		Nivolumab vs. placebo	III	Checkmate-577 (NCT02743494)	Ongoing
		Nivolumab + ipilimumab or nivolumab + fluorouracil + cisplatin vs. fluorouracil + cisplatin	III	Checkmate-648 (NCT03143153)	Ongoing
	SHR-1210	SHR-1210 alone	I	NCT0274293	ORR 30% and median PFS 3.6 months in ESCC
		SHR-1210 vs. docetaxel or irinotecan	III	NCT03099382	N/A
CTLA-4	Ipilimumab	N/A	I	NCT01738139	Ongoing
PD-1/CTLA-4	Nivolumab/ipilimumab	Nivolumab (3 mg/kg) vs. nivolumab (1 mg/kg) + ipilimumab (3 mg/kg) vs. nivolumab (3 mg/kg) + ipilimumab (1 mg/kg)	I/II	CheckMate-032	ORR in patients with gastric, esophageal, or gastroesophageal junction cancer: 12% vs. 24% vs. 8%

N/A not available, ORR objective response rate, EC esophageal cancer, ESCC esophageal squamous cell carcinoma, EAC esophageal adenocarcinoma, OS overall survival, PFS progression-free survival, PD-1 programmed death protein-1, CTLA-4 cytotoxic T lymphocyte-associated protein 4