Recommendations for standardizing biopsy acquisition and histological assessment of immune checkpoint inhibitor-associated colitis.

Immune checkpoint inhibitor-associated colitis (ICIC) affects approximately 15% of cancer patients treated with immunotherapy. Although histological evaluation is potentially valuable for both the diagnosis of ICIC and evaluation of disease activity, use in clinical practice is heterogeneous. We aimed to develop expert recommendations to standardize histological assessment of disease activity in patients with ICIC. Using the modified Research and Development/University of California Los Angeles (RAND/UCLA) appropriateness methodology, an international panel of 11 pathologists rated the appropriateness of 99 statements on a 9-point Likert scale during two rounds of anonymous voting. Results were discussed between rounds using moderated videoconferences. There are currently no disease-specific instruments for assessing histological features of ICIC. The panel considered that colonoscopy with at least three biopsies per segment from a total of at least five segments, including both endoscopically normal and inflamed areas, was appropriate for tissue acquisition. They agreed that biopsies should be oriented such that the long axis of the colonic crypts is visualized and should be stained with hematoxylin and eosin. Histological items that the panel voted were appropriate to evaluate in ICIC included the degree of structural/architectural change, chronic inflammatory infiltrate, lamina propria and intraepithelial neutrophils, crypt abscesses and destruction, erosions/ulcerations, apoptosis, surface intraepithelial lymphocytosis, and subepithelial collagen thickness. The appropriateness of routine immunohistochemistry was uncertain. These expert recommendations will help standardize assessment of histological activity in patients with ICIC. The panel also identified the development and validation of an ICIC-specific histological index as a research priority.
Competing Interests: Competing interests: CM has received consulting fees from AbbVie, Alimentiv, Amgen, AVIR Pharma, Bristol Myers Squibb, Ferring, Fresenius Kabi, Janssen, McKesson, Mylan, Takeda, Pfizer, Roche; speaker's fees from AbbVie, Amgen, AVIR Pharma Inc, Alimentiv, Ferring, Janssen, Takeda, and Pfizer; research support from Pfizer. RiKP has received consulting fees from AbbVie, Eli Lilly, Allergan, Genentech, and Alimentiv. DFS has received consulting fees from Merck, Diaceutics, Pfizer, Allakos, and Alimentiv; stock ownership in Satisfai Health. JK has received advisory fees from Clovis Oncology, AstraZeneca, and Tesaro. LG is an employee of Alimentiv. SCM is an employee of Alimentiv. JKM is an employee of Alimentiv. RMF receives consulting fees from Alimentiv and has received fees from Bristol Myers Squibb, Janssen, and Takeda. RK has received consulting fees from Alimentiv. GYL has received consulting fees from Alimentiv. ReKP has received consulting fees from Alimentiv. CR has received consulting fees from Alimentiv. BGF is a scientific advisory board member for AbbVie, Allergan, Amgen, AstraZeneca, Avaxia Biologics Inc., Boehringer-Ingelheim, Bristol-Myers Squibb, Celgene, Elan, Biogen, Ferring, Genentech–Roche, Janssen–Johnson & Johnson, Merck, Millennium, Nestlé, Novo Nordisk, Novartis, Pfizer, Prometheus, Protagonist, Receptos, Salix, Sigmoid Pharma, Takeda, Teva, TiGenix, Tillotts Pharma, and UCB Pharma; consulting fees from AbbVie, Actogenix, Akros, Albireo Pharma, Allergan, Amgen, AstraZeneca, Avaxia Biologics, Avir Pharma, Axcan, Baxter Healthcare, Biogen Idec, Boehringer Ingelheim, Bristol-Myers Squibb, Calypso Biotech, Celgene, Elan–Biogen, EnGene, Ferring, Genentech–Roche, GiCare Pharma, Gilead Sciences, Given Imaging, GlaxoSmithKline, Ironwood, Janssen Biotech–Centocor, Janssen–Johnson & Johnson, Kyowa Hakko Kirin, Eli Lilly, Merck, Mesoblast Pharma, Millennium, Nestlé, Novo Nordisk, Novartis, Pfizer, Prometheus, Protagonist, Receptos Salix, Sanofi, Shire, Sigmoid Pharma, Synergy Pharma, Takeda, Teva, TiGenix, Tillotts Pharma, UCB Pharma, Vertex, VHsquared, Wyeth, Zealand, and Zygenia; lecture fees from AbbVie, Janssen–Johnson & Johnson, Takeda, and UCB Pharma, and grant support from AbbVie, Amgen, AstraZeneca, Bristol-Myers Squibb, Janssen Biotech–Centocor, Janssen–Johnson & Johnson, Pfizer, Receptos, Sanofi, and Takeda, and is the Senior Scientific Officer of Alimentiv Inc. VJ has received has received consulting/advisory board fees from AbbVie, Alimentiv (formerly Robarts Clinical Trials), Arena pharmaceuticals, Asahi Kasei Pharma, Asieris, Bristol Myers Squibb, Celltrion, Eli Lilly, Ferring, Fresenius Kabi, Galapagos, GlaxoSmithKline, Genentech, Gilead, Janssen, Merck, Mylan, Pandion, Pendopharm, Pfizer, Protagonist, Reistone Biopharma, Roche, Sandoz, Second Genome, Takeda, Teva, Topivert; speaker’s fees from, Abbvie, Ferring, Galapagos, Janssen Pfizer Shire, Takeda.
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