Here, we describe the first placebo-controlled trial of vaginal microbiota transplantation (VMT) in women with asymptomatic dysbiosis without the use of antibiotic pretreatment. Importantly, we also describe the implementation of a donor program and banking of donor cervicovaginal secretions (CVS) while retaining sample viability, which is crucial to allow for scale-up and confirmatory quality testing. By metagenome sequencing, we demonstrate that VMT provided a significant increase in combined Lactobacillus species in the active arm and strain-level genetic analysis confirmed Lactobacillus engraftment. Moreover, VMT was well tolerated and showed a good safety profile. Furthermore, a shift toward increased Lactobacillus was associated with a change in the expression profile of genes in the complement pathway to a more anti-inflammatory profile. Vaginal microbial and immune profile restoration using VMT may have a positive impact on a wide range of conditions in women’s health.

Elleke F. Bosma, Brynjulf Mortensen, Kevin DeLong, Helene Baek Juel, Amalie M. Axelsen, Marouschka J. Scheeper, Colleen Acosta, Ulrich K. Binne, and Johan E.T. van Hylckama Vlieg are employees of Freya Biosciences, ApS. Randi Rich, Thomas Gundelund Rasmussen, Colleen Acosta, Ulrich K. Binne, Anne Bloch Thomsen, Johan E.T. van Hylckama Vlieg, and Laura M. Ensign are cofounders and shareholders of Freya Biosciences, ApS. Laura M. Ensign is a coinventor on patent filings in the area of microbial transplantation. Laura M. Ensigns arrangements have been reviewed and approved by the Johns Hopkins University in accordance with its conflict of interest policies. Fergus McCarthy received a consulting fee from Atlantia Clinical Trials for his role as acting Clinical Lead on the study. Timothy G. Dinan is Medical Director at Atlantia Clinical Trials. Paul D. Cotter, Marcus O'Brien, Shriram Patel, and Sarita A. Dam are employees at Seqbiome Ltd. All other authors declare that they have no competing interests.

NCT05114031

The study was funded by Freya Biosciences, ApS Fruebjergvej, 2100 Copenhagen, Denmark.

I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.

Yes

The details of the IRB/oversight body that provided approval or exemption for the research described are given below:

The study protocol and related documents describing all study procedures and the donor program were all approved by the Clinical Research Ethics Committee of the Cork Teaching Hospitals (Cork, Ireland) before the study was initiated. The study was registered at ClinicalTrials.gov prior to enrolling participants (NCT05114031).

I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals.

Yes

I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance).

Yes

I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable.

Yes

The datasets generated during and/or analyzed during the current study are available from the corresponding author on reasonable request.