Low serum trough levels are associated with post-surgical recurrence in Crohn's disease patients undergoing prophylaxis with adalimumab

Background: Whether therapeutic drug monitoring of biologic therapy can predict the efficacy of adalimumab to prevent postoperative Crohn's disease recurrence is unknown. Aim: To investigate whether adalimumab trough levels and anti-adalimumab antibodies correlate with endoscopic and clinical outcomes in a series of patients treated with prophylactic adalimumab monotherapy after resective surgery. Methods: Post hoc analysis of a randomized, mesalamine-controlled trial. Adalimumab trough levels and antibodies were analysed every 8 weeks for 2 years using an homogeneous mobility shift assay. Results: At two years, 1/6 patient had clinical recurrence and 1/6 patient had endoscopic and clinical recurrence. At baseline (9.5 vs. 14.4 mcg/mL) and during follow-up [7.5 (4.4-9.8) vs. 13.9 (8.9-23.6) mcg/mL, p < 0.01], median adalimumab trough levels in patients with clinical or endoscopic recurrence were lower than in those who maintained remission. Persistent antibodies-against-adalimumab were detected in the patient with both endoscopic and clinical recurrence. Conclusion: Measurement of adalimumab trough levels and anti-adalimumab antibodies after surgery could be useful to further reduce postoperative recurrence. (C) 2014 Editrice Gastroenterologica Italiana S.r.l. Published by Elsevier Ltd. All rights reserved.