Defining difficult-to-treat inflammatory bowel disease: why and how.

Competing Interests: SD has served as a speaker, consultant, and advisory board member for Schering-Plough, AbbVie, Actelion, Alphawasserman, AstraZeneca, Cellerix, Cosmo Pharmaceuticals, Ferring, Genentech, Grunenthal, Johnson and Johnson, Millennium Takeda, Merck Sharp & Dohme, Nikkiso Europe, Novo Nordisk, Nycomed, Pfizer, Pharmacosmos, UCB Pharma, and Vifor. LPB reports personal fees from Galapagos, AbbVie, Janssen, Genentech, Ferring, Tillots, Pharmacosmos, Celltrion, Takeda, Boehringer Ingelheim, Pfizer, Index Pharmaceuticals, Sandoz, Celgene, Biogen, Samsung Bioepis, Alma, Sterna, Nestle, Inotrem, Enterome, Allergan, MSD, Roche, Arena, Gilead, Hikma, Amgen, Bristol Myers Squibb, Vifor, Norgine, Mylan, Lilly, Fresenius Kabi, Oppilan Pharma, Sublimity Therapeutics, Applied Molecular Transport, OSE Immunotherapeutics, Enthera, and Theravance; has received grants from AbbVie, Merck Sharp & Dohme, and Takeda; and has stock options from Clinical Trials Mobile Application. SG is a steering committee member for Pfizer, Janssen, AbbVie, Bristol Myers Squibb, Celgene, and Boehringer Ingelheim and has received speaker honoraria from AbbVie, Janssen, Takeda, Shield, Ferring, and Falk Pharma. TLP declares no competing interests.