Lookup NU author(s): Dr Chris Lamb,
Dr John Mansfield,
Professor John Kirby
This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND).
BACKGROUND & AIMS: Etrolizumab is a humanized monoclonal antibody against the beta 7 integrin subunit that has shown efficacy vs placebo in patients with moderate to severely active ulcerative colitis (UC). Patients with colon tissues that expressed high levels of the integrin alpha E gene (ITGAE) appeared to have the best response. We compared differences in colonic expression of ITGAE and other genes between patients who achieved clinical remission with etrolizumab vs those who did. METHODS: We performed a retrospective analysis of data collected from 110 patients with UC who participated in a phase 2 placebo-controlled trial of etrolizumab, as well as from 21 patients with UC or without inflammatory bowel disease (controls) enrolled in an observational study at a separate site. Colon biopsies were collected from patients in both studies and analyzed by immunohistochemistry and gene expression profiling. Mononuclear cells were isolated and analyzed by flow cytometry. We identified biomarkers associated with response to etrolizumab. In the placebo-controlled trial, clinical remission was defined as total Mayo Clinic Score <= 2, with no individual subscore > 1, and mucosal healing was defined as endoscopic score <= 1. RESULTS: Colon tissues collected at baseline from patients who had a clinical response to etrolizumab expressed higher levels of T-cell - associated genes than patients who did not respond (P <.05). Colonic CD4(+) integrin alpha E+ cells from patients with UC expressed higher levels of granzyme A messenger RNA (GZMA mRNA) than CD4(+) alpha E- cells (P <.0001); granzyme A and integrin aE protein were detected in the same cells. Of patients receiving 100 mg etrolizumab, a higher proportion of those with high levels of GZMA mRNA (41%) or ITGAE mRNA (38%) than those with low levels of GZMA (6%) or ITGAE mRNA (13%) achieved clinical remission (P <.05) and mucosal healing (41% GZMA(high) vs 19% GZMA(low) and 44% ITGAE(high) vs 19% ITGAE(low)). Compared with ITGAE(low) and GZMA(low) patients, patients with ITGAE(high) and GZMA(high) had higher baseline numbers of epithelial crypt-associated integrin alpha E+ cells (P <.01 for both), but a smaller number of crypt-associated integrin alpha E+ cells after etrolizumab treatment (P <.05 for both). After 10 weeks of etrolizumab treatment, expression of genes associated with T-cell activation and genes encoding inflammatory cytokines decreased by 40% - 80% from baseline (P <.05) in patients with colon tissues expressing high levels of GZMA at baseline. CONCLUSIONS: Levels of GZMA and ITGAE mRNAs in colon tissues can identify patients with UC who are most likely to benefit from etrolizumab; expression levels decrease with etrolizumab administration in biomarkerhigh patients. Larger, prospective studies of markers are needed to assess their clinical value.
Author(s): Tew GW, Hackney JA, Gibbons D, Lamb CA, Luca D, Egen JG, Diehl L, Anderson JE, Vermeire S, Mansfield JC, Feagan BG, Panes J, Baumgart DC, Schreiber S, Dotan I, Sandborn WJ, Kirby JA, Irving PM, De Hertogh G, Van Assche GA, Rutgeerts P, O'Byrne S, Hayday A, Keir ME
Publication type: Article
Publication status: Published
Print publication date: 01/02/2016
Online publication date: 30/10/2015
Acceptance date: 22/10/2015
Date deposited: 08/01/2019
ISSN (print): 0016-5085
ISSN (electronic): 1528-0012
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