Probiotic vs. placebo and metformin: probiotic dietary intervention in polycystic ovary syndrome – A randomized controlled trial

BACKGROUND: Polycystic Ovary Syndrome (PCOS) is a very common endocrine disorder with a variety of symptoms. Current treatment options include the contraceptive pill as well as metformin, however both treatments are limited to specific symptoms and have common side effects. METHODS: This phase IV study is a monocentric, double blinded randomized clinical trial comparing the effects of six months of probiotic intervention to a placebo, with an additional open-label metformin arm as a positive control in a total of 180 participants with PCOS. The first of three visits is the screening visit, where inclusion/exclusion criteria are assessed. At the first visit, they are randomised into one of the three treatment arms equally and receive their study medication. After six months, all assessments from the first two visits are repeated. The primary endpoint is the change in free testosterone levels after the intervention, while secondary endpoints include changes in hormonal and metabolic parameters associated with PCOS as well as the gut microbial composition and diversity after intervention. DISCUSSION: Based on new insights into the role of the gut microbiome in PCOS development, this study is exploring the potential of using probiotics to treat women with PCOS symptoms. If successful, this new therapy approach could open a new realm of possibilities for treating PCOS. To our knowledge, this is the first study comparing probiotic intervention with not only placebo treatment, but also metformin. This study has been approved by the ethics committee of the Medical University of Graz (EC number 32–230 ex 19/20). REGISTRATION: EudraCT number: 2020-000228-20. Clinicaltrials.gov identifier: NCT04593459. PROTOCOL VERSION: Version 1.5 dated 29th November 2021.