With the European Crohn ’ s and Colitis Organization:

The advent of biological therapy has revolutionized infl ammatory bowel disease (IBD) care. Nonetheless, not all patients require biological therapy. Selection of patients depends on clinical characteristics, previous response to other medical therapy, and comorbid conditions. Availability, reimbursement guidelines, and patient preferences guide the choice of fi rst-line biological therapy for luminal Crohn ’ s disease (CD). Infl iximab (IFX) has the most extensive clinical trial data, but other biological agents (adalimumab (ADA), certolizumab pegol (CZP), and natalizumab (NAT)) appear to have similar benefi ts in CD. Steroid-refractory, steroid-dependent, or complex fi stulizing CD are indications for starting biological therapy, after surgical drainage of any sepsis. For fi stulizing CD, the effi cacy of IFX for inducing fi stula closure is best documented. Unique risks of NAT account for its labeling as a second-line biological agent in some countries. Patients who respond to induction therapy benefi t from systematic re-treatment. The combination of IFX with azathioprine is better than monotherapy for induction of remission and mucosal healing up to 1 year in patients who are na ï ve to both agents. Whether this applie