T04.02.21 LOSS OF RESPONSE AFTER FIRST LINE ANTI-TNF THERAPY IN PATIENTS WITH INFLAMMATORY BOWEL DISEASE: PRATICAL APPROACH AND MANAGEMENT. (1st October 2020) - Guella, S.; Scrivo, B.; Calvaruso, V.; Giuffrida, E.; Busacca, A.; Guida, L.; Carrozza, L.; Cappello, M.