Feasibility, safety and tolerability of estrogen and/or probiotics for improving vaginal health in Canadian African, Caribbean, and Black women: A pilot phase 1 clinical trial.

Publisher: Public Library of Science Country of Publication: United States NLM ID: 101285081 Publication Model: eCollection Cited Medium: Internet ISSN: 1932-6203 (Electronic) Linking ISSN: 19326203 NLM ISO Abbreviation: PLoS One Subsets: MEDLINE

Original Publication: San Francisco, CA : Public Library of Science

Probiotics*/administration & dosage ; Probiotics*/adverse effects ; Vagina*/microbiology ; Estrogens*/administration & dosage; Humans ; Female ; Adult ; Middle Aged ; Young Adult ; Adolescent ; Pilot Projects ; Canada ; Black People ; Vaginosis, Bacterial/drug therapy ; Feasibility Studies ; Administration, Intravaginal ; Caribbean Region ; Prospective Studies ; HIV Infections

Background: A dysbiotic vaginal microbiome (VMB) is associated with clinical conditions such as bacterial vaginosis (BV) and an increased risk of human immunodeficiency virus (HIV-1) infection. Considering the high prevalence of BV among African, Caribbean and Black (ACB) women, we conducted a prospective, randomized, open-label phase 1 clinical trial to determine the feasibility, safety and tolerability of administering low-dose estrogen, probiotics or both in combination to improve vaginal health and decrease HIV-1 susceptibility.
Methods: ACB women aged 18-49 from the Greater Toronto Area (GTA) were randomized to one of four study arms: intravaginal estradiol (Estring©; 7.5mg/day); a vaginal probiotic (RepHresh™ Pro-B™) administered twice daily; a combination of Estring© and vaginal RepHresh™ Pro-B™ (twice daily); or the Estring© and oral RepHresh™ Pro-B™ (twice daily), for a duration of 30 days. Feasibility was evaluated through enrolment, retention, and adherence rates, while safety and tolerability were determined by a pre- and post-treatment blood panel and reported adverse events (AEs).
Results: Overall, 63 ACB women were screened, 50 were enrolled and received the intervention while 41 completed the study, resulting in 80% enrollment and 82% retention rates. Overall adherence to the study protocol was high at 93%, with an adherence of 92% for RepHresh™ Pro-B™ and 97% for Estring©. A total of 88 AEs were reported by 29 participants which were mild (66/88; 75%) and largely resolved (82/88;93%) by the end of the study, with no serious AEs (SAEs) noted. In addition, a panel of safety blood markers measured pre- and post-intervention confirmed no clinically significant changes in blood chemistry or blood cell count.
Conclusion: Overall, the administration of intravaginal estrogen and/or probiotics in pre-menopausal ACB women is feasible, safe, and well tolerated.
Trial Registration: The trial was registered with Clinicaltrials.gov (NCT03837015) and CIHR HIV Clinical Trials (CTN308).
Competing Interests: I have read the journal’s policy and the authors of this manuscript have the following competing interests: GR developed the probiotic strains GR-1 and RC-14 but has had no financial interest in them for 15 years. GR consults for Seed, a company producing probiotic strains not used in this study. He was not paid salary for any roles with the company. All the other authors have declared no conflict of interest. This does not alter our adherence to PLOS One policies on sharing materials and data.”
(Copyright: © 2025 Gill et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

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ClinicalTrials.gov NCT03837015

0 (Estrogens)

Date Created: 20250121 Date Completed: 20250121 Latest Revision: 20250129

20250129

PMC11750099

10.1371/journal.pone.0315576

39836666