Continuation of thiopurines for more than six months in patients with Crohn’s disease (CD) offered no clear benefit over scheduled adalimumab (ADA) monotherapy maintenance, according to results from the DIAMOND2 study.
“This observation suggests that further consideration of the thiopurine combination in ADA maintenance therapy for CD is necessary from the viewpoints of benefit and risk,” wrote researchers led by Tadakazu Hisamatsu, of Kyorin University School of Medicine, Japan, and colleagues.
DIAMOND2 included 50 patients who were in corticosteroid-free clinical remission for six months or longer and had scheduled maintenance with ADA combined with thiopurines. These patients were randomly assigned to either continue or discontinue thiopurines; all other patients kept receiving their scheduled ADA maintenance for 52 weeks.
Rates of corticosteroid-free remission were not significantly difference between the two groups at week 52 (95.5% for the continue group vs. 92.9% for the discontinue group). Additionally, trough levels of ADA and the proportion of patients with anti-ADA positivity were both similar at week 52 between the two groups of patients.
“At week 52, continuation of thiopurines did not show benefit with regard to serum level of CRP, endoscopic activity, triple remission, or trough level of ADA in serum,” the researchers wrote. “Only a change in the Simple Endoscopic Score for Crohn’s Disease at week 52 from baseline tended to be higher in the discontinue group.” However, this difference was not statistically significant.
None of the patients who continued thiopurine therapy reported adverse effects and two who discontinued thiopurines reported adverse events (common cold). No serious adverse effects were reported.
Based on these results, the researchers wrote that they “believe that all patients who are in clinical remission do not necessarily need long-term use of thiopurines with ADA maintenance.”