Competing interests: CVA-C has received grants from Celgene and Takeda outside the scope of the submitted work. AW reports personal fees outside the submitted work from Ferring Pharmaceuticals, Janssen, and Takeda. ST reports outside the submitted work receipt of grants/research support from AbbVie, Buhlmann, Celgene, IOIBD, Janssen, Lilly, Pfizer, Takeda, UCB, Vifor, and Norman Collisson Foundation; consulting fees from AbbVie, Allergan, Amgen, Arena, Asahi, Astellas, Biocare, Biogen, Boehringer Ingelheim, Bristol-Myers Squibb, Buhlmann, Celgene, Chemocentryx, Cosmo, Enterome, Ferring, Giuliani SpA, GSK, Genentech, Immunocore, Immunometabolism, Indigo, Janssen, Lexicon, Lilly, Merck, MSD, Neovacs, Novartis, NovoNordisk, NPS Pharmaceuticals, Pfizer, Proximagen, Receptos, Roche, Sensyne, Shire, Sigmoid Pharma, SynDermix, Takeda, Theravance, Tillotts, Topivert, UCB, VHsquared, Vifor, and Zeria; speaker fees from AbbVie, Amgen, Biogen, Ferring, Janssen, Lilly, Pfizer, Shire, and Takeda; no stocks or share options. NMC reports research grants outside the submitted from Abbvie, Shire, Takeda, Pfizer, Eli Lilly, Jansenn, 4D Pharma, and lecture fees Abbvie. JS has received lecture fees from Takeda and from the Falk Foundation.