Thiopurines Do Not Induce Remission in Crohn Disease

The efficacy of thiopurines — azathioprine and 6-mercaptopurine — for induction of remission in Crohn disease has been controversial. Now, results of two randomized, controlled trials confirm their lack of efficacy in this setting.

In a double-blind trial, investigators randomized 131 adult patients newly diagnosed with Crohn disease to receive azathioprine (2.5 mg/kg per day) or placebo. Corticosteroids (but no other concomitant medications) were allowed for control of disease activity. After 76 weeks, rates of sustained corticosteroid-free remission were 44.1% in the azathioprine group and 36.5% in the placebo group (P=0.48). Relapse rates and corticosteroid requirements were similar between groups. In a post-hoc analysis, relapse defined as Crohn's Disease Activity Index score ≥220 was lower with azathioprine versus placebo (11.8% vs. 30.2%; P=0.01).

In an open-label study, investigators randomized 132 patients recently diagnosed with Crohn disease (within the previous 6 months) and at high risk for disabling disease to receive azathioprine (2.5 mg/kg per day) or conventional management (involving azathioprine only for select circumstances; e.g., poor response to corticosteroids). The primary end point was the percentage of trimesters in remission (without use of steroids or anti-tumor necrosis factor [TNF] agents) and was similar between the azathioprine and conventional management groups (67% and 56%; P=0.69). Patients in the azathioprine group were less likely to require perianal surgery, but no difference in intestinal surgeries was observed.