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.