Competing interests: CWL has received research support from Abbvie and Gilead, acted as a consultant to Abbvie, Janssen, Takeda, Pfizer, MSD, Hospira, Pharmacosmos, GSK, Gilead, Topivert, Vifor Pharma, Dr Falk, Oshi Health, Trellus Health and Iterative Scopes; he has received speaking fees and travel support from Pfizer, Janssen, Abbvie, MSD, Takeda, Shire, Ferring, Hospira, Warner-Chilcott and Dr Falk. PMI has received fees for speaking on the behalf of or acting in an advisory capacity for AbbVie, Arena, Biogen, Celgene, Ferring, Prometheus, Shire, Warner Chilcott, Takeda, MSD, Vifor Pharma, Pharmacosmos, Topivert, Genentech, Hospira, Samsung Bioepis, VH2, Janssen, Sandoz, Lilly and Roche and has received financial support for research from MSD, Pfizer and Takeda. LB has received consulting fees from Janssen and Pfizer, lecture fees from Abbvie, Janssen, MSD, Ferring Pharmaceuticals, Mayoly-Spendler, Takeda and Tillots, and research support from Abbott, Ferring Pharmaceuticals, Hospira-Pfizer, Janssen, MSD, Takeda and Tillots.