Multi‐treatment resistance to biological treatment in patients with psoriasis: Definitions and implications

S. E. Thomas carries out clinical trials for Janssen and Novartis and has received speaking fees from AbbVie and Eli Lilly. All funding is not personal but goes to the independent Research Fund of the Department of Dermatology, Radboud University Medical Centre (Radboudumc), Nijmegen, The Netherlands. J. M. P. A. van den Reek carried out clinical trials for AbbVie, Celgene, Almirall and Janssen and has received speaking fees/attended advisory boards from AbbVie, Janssen, BMS, Almirall, LEO Pharma, Novartis, UCB and Eli Lilly and reimbursement for attending or chairing a symposium from Janssen, Pfizer, Celgene and AbbVie. All funding is not personal but goes to the independent research fund of the Department of Dermatology, Radboud University Medical Centre (Radboudumc), Nijmegen, The Netherlands. E. M. G. J. de Jong has received research grants for the independent research fund of the Department of Dermatology, Radboud University Medical Centre (Radboudumc), Nijmegen, The Netherlands, from AbbVie, BMS, Janssen Pharmaceutica, LEO Pharma, Novartis, and UCB for research on psoriasis. Has acted as consultant and/or paid speaker for and/or participated in research sponsored by companies that manufacture drugs used for the treatment of psoriasis or eczema including AbbVie, Amgen, Almirall, Boehringer Ingelheim, BMS, Celgene, Galapagos, Janssen Pharmaceutica, LEO Pharma, Lilly, Novartis, Sanofi and UCB. All funding is not personal but goes directly to the Department of Dermatology, Radboud University Medical Centre (Radboudumc), Nijmegen, The Netherlands. M. E. Otero has acted as a consultant for Eli Lilly. I. M. Haeck is a consultant, advisory board member and/or speaker for Sanofi Genzyme and Regeneron Pharmaceuticals, Pfizer, LEO Pharma, AbbVie, Janssen and Eli Lilly. S. R. P. Dodemont has attended advisory boards for Abbvie, Janssen and LEO Pharma. R. A. Tupker has attended advisory boards from LEO Pharma and Eli Lilly Netherlands. R. R. M. C. Keijsers has acted as a paid chairman for Janssen Immunology. M. B. A. van Doorn is or recently was a speaker and/or advisor for and/or has received research funding from Novartis, AbbVie, Almirall, LEO Pharma, Sanofi, Janssen, UCB, BMS, outside the submitted work. M. Tjioe has carried out clinical trials for Abbvie, Allmiral, Cellgene, Eli Lilly, Incyte, Leo Pharma, Moonlake, Novartis. All trial funding is not personal but goes to the independent research fund of the Department of Dermatology of Bravis Hospital Bergen op Zoom, the Netherlands. He has received speaking fees/attended advisory boards from Abbvie, Novartis, Pfizer and UCB and reimbursement for attending a symposium from UCB. N. F. T. Henckens, P. P. M. van Lumig, P. M. Ossenkoppele, J. H. J. Hendricksen-Roelofzen, J. E. M. Körver, M. A. M. Berends, R. J. Lindhout, A. M. Oostveen, B. Peters, J. M. Mommers, W. R. Veldkamp, A. L. A. Kuijpers, M. M. Kleinpenning have no conflict of interest. The analyses that support the findings of this study are available on request from the corresponding author. The individual patient data are not publicly available due to privacy or ethical restrictions.