Randomized, Placebo-controlled, Double-blind Trial of Boswellia serrata in Maintaining Remission of Crohn's Disease: Good Safety Profile but Lack of Efficacy

Background: Complementary therapies are frequently used by patients with inflammatory bowel disease (IBD). The aim of this study was to evaluate the efficacy and safety of long-term therapy with a new Boswellia serrata extract (Boswelan, PS0201Bo) in maintaining remission in patients with Crohn's disease (CD). Methods: In 22 German centers a double-blind, placebo-controlled, randomized, parallel study was performed. In all, 108 outpatients with CD in clinical remission were included. Patients were randomized to Boswelan (3x2 capsules/day; 400 mg each) or placebo for 52 weeks. The primary endpoint was the proportion of patients in whom remission was maintained throughout the 52 weeks. Secondary endpoints were time to relapse, changes of Crohn's Disease Activity Index (CDAI), and IBD Questionnaire (IBDQ) scores. Results: The trial was prematurely terminated due to insufficient discrimination of drug and placebo with regard to the primary efficacy endpoint. A total of 82 patients were randomized to Boswelan (n = 42) or placebo (n = 40). Sixty-six patients could be analyzed for efficacy. 59.9% of the actively treated patients and 55.3% of the placebo group stayed in remission (P = 0.85). The mean time to diagnosis of relapse was 171 days for the active group and 185 days for the placebo group (P = 0.69). With respect to CDAI, IBDQ, and laboratory measurements of inflammation, no advantages in favor of active treatment were detected. Regarding safety concerns, no disadvantages of taking the drug compared to placebo were observed. Conclusions: The trial confirmed good tolerability of a new Boswellia serrata extract, Boswelan, in long-term treatment of CD. However, superiority versus placebo in maintenance therapy of remission could not be demonstrated.