Efficacy and Safety of Anthocyanin-Rich Extract in Patients with Ulcerative Colitis: A Randomized Controlled Trial.

Bilberries are effective in inducing clinical, endoscopic, and biochemical improvement in ulcerative colitis (UC) patients. The aim of this study was to investigate the efficacy of anthocyanin-rich extract (ACRE), the bioactive ingredient of bilberries, in a controlled clinical trial in moderate-to-severe UC. A multi-center, randomized, placebo-controlled, double-blind study with a parallel group was conducted. Initially, the study was planned for 100 patients; nevertheless, it prematurely ended due to COVID-19. Patients had moderate-to-severe active UC at screening (a Mayo score of 6-12, an endoscopic sub-score ≥ 2) and were randomized at baseline. The primary endpoint was a clinical response (week 8, a total Mayo score reduction ≥ 3 points). Fecal calprotectin (FC) and a centrally read endoscopic response were among the secondary endpoints. Out of 48 patients (6 Swiss centers), 34 were randomized. Eighteen ACRE and eight placebo patients could be analyzed (per protocol set). Half (9/18) of ACRE patients and 3/8 of placebo patients responded clinically ( = 0.278). An improvement in the Mayo score was observed in the ACRE arm (77.8% vs. 62.5% placebo). FC dropped from 1049 ± 1139 to 557 ± 756 μg/g for ACRE but not for the placebo group (947 ± 1039 to 1040 ± 1179; = 0.035). Serious adverse events were rare. ACRE treatment did not yield significant superiority to the placebo. Furthermore, the placebo response was unusually high. Moreover, there was a significant calprotectin decrease at the end of treatment, indicative of ACRE efficacy in UC.