Precision medicine in inflammatory bowel disease: Individualizing the use of biologics and small molecule therapies

Table 1 Selected list of biomarkers in inflammatory bowel disease

Biomarker class	Biomarker	Clinical utility
Prognostic biomarkers	Anti-ompC, ASCA, ANCA, anti-CBir1, flagellin	Prediction of more severe CD phenotype- particularly stricturing and need for surgery
	CD 8+ T cell clonal signature	Prediction of more severe disease course and relapse in CD and UC
Surveillance of disease activity	Fecal calprotectin	Predictor of endoscopic disease activity as well as histologic inflammation, and relapse in asymptomatic patients with IBD
	MMP-9	Associated with disease activity in UC
	IL-22	Associated with disease activity in CD
Pharmacogenomics and prediction of safety	TPMT	Risk of thiopurine adverse reaction
	NUDT15	Risk of thiopurine adverse reaction, more common in East Asian/Asian populations
	Thiopurine metabolites (6TG, 6MMP)	Levels associated with adverse drug reaction: myelosuppression, hepatotoxicity. 6TG range also associated with therapy response
Prediction of response to therapy	Oncostatin M	Higher levels predictor of non-response to anti-TNF
	TREM-1	Low levels predictor of non-response to anti-TNF
	HLA-DQA1*05	Expression associated with risk of antibody formation to anti-TNF
	IL-22	Higher level associated with response to anti-IL23p19 (brazikumab)

ANCA: Anti-neutrophil cytoplasmic antibody; ASCA: Anti-Saccharomyces cerevisiae antibody; CD: Crohn’s disease; IBD: Inflammatory bowel disease; IL: Interleukin; MMP: Matrix metalloproteinase; NUDT15: Nudix hydrolase 15; ompC: Outer membrane protein C; TG: Thioguanine; TNF: Tumor necrosis factor; TPMT: Thiopurine methyltransferase; TREM: Triggering receptor expressed on myeloid cells; UC: Ulcerative colitis.