P342 Adalimumab prevents post-operative Crohn's disease recurrence and is superior to thiopurines: Early results from the prospective POCER study

Postsurgical Prophylaxis in Crohn's Disease: Which Patients, Which Agents?

Crohn's disease (CD) evolution is characterized by increasing proportions of patients developing complications such as strictures, abscesses and fistulas that require surgical management. After resection of a diseased intestinal segment, CD recurrence concerns up to 60% of patients within a year post surgery. The mucosa just above the site of the intestinal anastomosis is at particularly high risk of relapse. Prophylactic medical therapy to prevent recurrence has been shown to be effective with a variety of medications, but the recurrence rate remains high, demanding that a better risk stratification of patients be achieved. Recognized risk factors for postsurgical CD recurrence include young age at diagnosis and at surgery, smoking, need for repeated surgeries and penetrating disease. These patients require full dose immunosuppressive or anti-tumor necrosis factor (anti-TNF) therapy, which should be initiated in the immediate postoperative period, to prevent the onset of an inflammatory activity in the bowel. Systematic follow-up by endoscopy to monitor treatment benefit should also be part of the management, as endoscopic recurrence heralds clinical relapse in these patients. The role of noninvasive markers of mucosal inflammation, such as stool calprotectin levels, show promise to complete this monitoring. Although the efficacy of mesalazine and imidazole antibiotics has been long recognized, more aggressive approaches, such as thiopurines and anti-TNF antibodies, have shown higher efficacies in direct comparison trials. The potential place of anti-homing agents is not yet defined, but these agents should in principle be of interest for this prophylactic indication due to their mode of action and interesting side-effect profile. The current recommendations are based on a step-up approach that includes immunosuppressors and/or imidazole antibiotics, followed by an anti-TNF agent, such as infliximab and adalimumab, both already tested in randomized trials in this indication. When endoscopic recurrence is identified during follow-up, upscaling to anti-TNF or dose escalation is advocated.

Use of thiopurines in inflammatory bowel disease

The use of thiopurines as immunosuppression for the treatment of refractory or chronic active inflammatory bowel disease is established for both Crohn's disease and ulcerative colitis. Nevertheless, many questions remain concerning the optimal treatment regimens of azathioprine, 6-mercaptopurine and thioguanine. We will briefly summarize dose recommendations, indications for thiopurine therapy and side effects which are relevant in clinical practice. We discuss some currently debated topics, including the combination of azathioprine and allopurinol, switching of thiopurine therapy in case of side effects, the use of azathioprine in pregnancy, the infection risk using thiopurines and the evidence when to stop thiopurines. Excellent reviews have been published on the thiopurine metabolic pathway which will not be discussed here in detail.