Main idea: This study shows that B bifidum HI-MIMBb75 substantially alleviates IBS and its symptoms in a real-life setting. These results indicate that specific beneficial bacterial effects are mediated independently of cell viability.
Bifidobacterium bifidum MIMBb75 is one of a few probiotic strains that have been shown to be effective in the treatment of irritable bowel syndrome (IBS) and its symptoms. Non-viable strains might have advantages over viable bacteria for product stability and standardization, as well as for tolerability because safety concerns have been raised for specific patient groups who are susceptible to infection. We aimed to assess the efficacy of non-viable heat-inactivated (HI) B bifidum MIMBb75 (SYN-HI-001) in the treatment of IBS and its symptoms.
The patients received either two placebo capsules or two capsules with a combined total of 1 × 109 non-viable B bifidum HI-MIMBb75 cells to be taken orally once a day for 8 weeks. Patients were screened between April 15, 2016, and Feb 3, 2017, and 443 patients were allocated to the placebo group (n=222) or the B bifidum HI-MIMBb75 group (n=221). The composite primary endpoint was reached by 74 of 221 patients in the B bifidum HI-MIMBb75 group compared with 43 of 222 in the placebo group. No serious adverse events occurred in the B bifidum HI-MIMBb75 group; seven adverse events suspected to be related to the study product were reported in the B bifidum HI-MIMBb75 group as were eight in the placebo group. No deaths were reported in this study. The most common reported adverse event with a suspected relationship to the study product was abdominal pain, which was reported in two (<1%) patients in the B bifidum HI-MIMBb75 group and one (<1%) in the placebo group. Tolerability was rated as ‘very good’ or ‘good’ by 200 (91%) patients in the B bifidum HI-MIMBb75 group compared with 191 (86%) in the placebo group.