The London Position Statement of the World Congress of Gastroenterology on Biological Therapy for IBD with the European Crohn's and Colitis Organization: when to start, when to sto... by D'Haens, G, Panaccione, R, Higgins, P, Vermeire, S, Gassull, M, Chowers, Y, Hanauer, S, Herfarth, H, Hommes, D, Kamm, M, Löfberg, R, Quary, A, Sands, B, Sood, A, Watermeyer, G, Watermayer, G, Lashner, B, Lémann, M, Plevy, S, Reinisch, W, Schreiber, S, Siegel, C, Targan, S, Watanabe, M, Feagan, B