Effect of FB301 on Vaginal Bacterial Profile in Women With Asymptomatic Vaginal Dysbiosis Undergo… (NCT07453069) | Clinical Trial Compass
Not Yet RecruitingPhase 2
Effect of FB301 on Vaginal Bacterial Profile in Women With Asymptomatic Vaginal Dysbiosis Undergoing a Mock Frozen Embryo Transfer Cycle
United States30 participantsStarted 2026-04-15
Plain-language summary
The goal of this clinical trial is to evaluate FB301 during a mock frozen embryo transfer (FET) cycle in pre-menopausal women aged 18 to 40 years with a prior failed FET and a defined vaginal bacterial imbalance (dysbiosis).
The main question it aims to answer is:
• Does treatment with FB301 during a mock FET cycle change the proportion of participants who meet the predefined vaginal bacterial threshold compared with placebo?
Researchers will compare:
* FB301 given after an initial vaginal cleansing with chlorhexidine (an antiseptic solution),
* FB301 given after an initial vaginal cleansing with saline (saltwater), and
* A placebo capsule given after an initial vaginal cleansing with saline to determine whether these approaches affect vaginal bacterial composition and pregnancy outcomes.
Participants will take study treatment for 15 days during a "mock" FET cycle. In a mock cycle, participants receive the hormones needed to prepare the uterus for embryo transfer, but no embryo is transferred. After completing the mock cycle, participants will proceed with their planned frozen embryo transfer and will be followed during pregnancy until birth.
Participants will:
* Undergo a vaginal cleansing before receiving the first dose of FB301 or placebo
* Provide vaginal swab samples at up to 5 study visits
* Attend the study centre for up to 8 visits and participate in up to 4 follow-up phone calls
* Complete a mock FET cycle before proceeding with their planned frozen embryo transfer cycle
Participants who become pregnant will be followed until birth.
Who can participate
Age range18 Years – 40 Years
SexFEMALE
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Inclusion criteria
✓. Able to understand the study and sign a consent form.
✓. Is a woman aged 18 to 40 years.
✓. Still has regular menstrual periods (pre-menopausal).
✓. Has had at least one previous frozen embryo transfer (FET) that did not result in pregnancy within the past 3 years, and this was not due to either male infertility or blocked /damaged fallopian tubes.
✓. Planning to have a frozen embryo transfer (FET) using one good-quality embryo (grade 3BB or higher) and are considered medically suitable to proceed.
✓. Willing to have only one embryo transferred during the study cycle.
✓. A vaginal swab taken at the first study visit shows a specific vaginal microbiome imbalance required for this study (vaginal molecular dysbiosis).
✓. An ultrasound scan shows no problems with uterus or pelvis that would prevent pregnancy or greatly reduce the chance of pregnancy.
Exclusion criteria
What they're measuring
1
Proportion of participants with ≥90% combined relative abundance of Lactobacillus crispatus, L. jensenii, L. mulieris, L. gasseri, and L. paragasseri as measured by metagenomic sequencing.