Table 1.

Major classes of immune checkpoint inhibitors indicated for gastrointestinal cancers.

Target	Generic Name	Disease Category	FDA Indications
			Required Biomarker	Required Prior Therapy	Monotherapy 1	Combination 1
PD-1	Nivolumab	CRC	MSI-H/dMMR	Fluoropyrimidine, oxaliplatin and irinotecan	√	With/without ipilimumab
		HCC	None	Sorafenib	√	With/without ipilimumab
PD-1	Pembrolizumab	Solid tumor	MSI-H/dMMR or TMB-H 2	Previously treated with no satisfactory alternative treatment options	√	×
		CRC	MSI-H/dMMR	None or fluoropyrimidine, oxaliplatin and irinotecan	√	×
		HCC	None	Sorafenib	√	×
		GC	PD-L1 CPS ≥ 1	At least two prior lines of therapy including fluoropyrimidine- and platinum-containing chemotherapy and if appropriate, HER2 targeted therapy	√	×
PD-L1	Atezolizumab	HCC	None	None	×	With bevacizumab
CTLA-4	Ipilimumab	CRC	MSI-H/dMMR	Fluoropyrimidine, oxaliplatin and irinotecan	×	With nivolumab
		HCC	None	Sorafenib	×	With nivolumab

Abbreviations: CRC, colorectal cancer; HCC, hepatocellular carcinoma; GC, gastric cancer; MSI-H, microsatellite instability-high; dMMR, deficient DNA mismatch repair; TMB, tumor mutational burden. ¹ √ indicates FDA approval of therapy and × indicates lack of FDA approval. ² TMB-H is defined as TMB greater or equal to 10 mutations/megabases.