NCT07453069ClinicalTrials.gov

Effect of FB301 on Vaginal Bacterial Profile in Women With Asymptomatic Vaginal Dysbiosis Undergoing a Mock Frozen Embryo Transfer Cycle

A Randomized, Double-blind, Three Arm, Multi-center Phase 2 Study to Investigate the Molecular Efficacy and Safety of FB301/Chlorhexidine Compared With FB301/Sham and Placebo/Sham in a Mock FET Cycle in Female Participants 18-40 Years of Age With Asymptomatic Vaginal Molecular Dysbiosis Planning to Undergo a Frozen Embryo Transfer (FET) Cycle

RecruitingTaking participants now, according to the registry record.

Contact this study

In brief

Phase 230 participants sought4 sites1 country

Registered in 1 registry

ClinicalTrials.govNCT07453069Open this record at ClinicalTrials.govSynced 2 weeks ago

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Trial information is shown as published by the registry, in its original language.

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How this study is set up

The points below are drawn from the public registry record for this study. Each one cites the field or sentence it came from. A dash (—) means the record does not state something — not that it is missing or wrong. Many well-run studies, especially small ones, leave some of these blank.

Present: Registered before enrolment beganFirst posted 2026-03-05; recorded start 2026-07-22
Present: Has a defined primary outcomeA primary outcome measure is listed in the record
Present: The primary outcome states a time frameThe primary outcome measure records a time frame
Present: Participants are randomly assignedAllocation is recorded as randomised
Present: Has a comparison groupThe record lists a placebo or comparator arm, or more than one study arm
Present: Uses blinding (masking)A masking level is recorded in the record
Not stated: An ethics committee is not stated in the registry recordThis registry's ingested record has no ethics-committee field
Not stated: Regulatory oversight (such as an IND or IDE) is not stated in the registry recordThis registry's ingested record has no regulatory-authorisation field
Not stated: A data monitoring committee is not stated in the registry recordThis registry's ingested record has no data-monitoring-committee fieldA data monitoring committee is not required for many smaller studies, and its absence here is not unusual.
Present: No cost to participants is mentioned in the recordChecked the summary, description and eligibility text; no cost-to-participant phrase found
Present: Sponsor has 3 other studies in this databaseCounted from the lead sponsor named in the record (Freya Biosciences ApS)
Not stated: No posted results from this sponsor are in this database yetBased on the sponsor’s studies in this database

The record lists 1 condition.
Lead sponsor type recorded as: industry.
Intervention regulatory context: investigational, within a phased regulatory pathway.

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What these facts mean, and what to ask · ruleset v1

Trial stature

Three independent measures of this study, described from its registry record — not a recommendation about it. A rigorous study by investigators nobody has heard of is better evidence than a weak study led by a famous one. How these are scored.

Methodological rigourSTRONG

A strong methodological design for a phase 2 study, judged from its ClinicalTrials.gov record.

How this score is built

Randomised allocation20/20
Participants are randomly allocated between arms
Blinding16/20
Triple-blind
Control arm13/15
Placebo / sham control arm
Primary-outcome specificity10/10
Named primary outcome with a defined time frame
Endpoint type3/10
Surrogate or intermediate endpoint (conservative default)
Multi-centre0/8
Single site, or site count not stated
Data monitoring committee7/7
A data monitoring committee is in place
Prospective registration5/5
Registered before the study start date
Protocol / SAP posted0/5
No protocol or SAP posted to the registry

ScaleSMALL

A small study: 30 participants (target), run at 4 sites.

How this score is built

Enrolment12/40
30 participants (target)
Site count0/25
1 sites
Country count0/15
Single country
Planned duration6/10
Planned over about 18 months
Sponsor scale2/10
Freya Biosciences ApS has led 4 trials in our corpus

Investigator standingUNKNOWN

We have no verifiable track record for the investigator named on this trial. That is common for early-career investigators and for records held outside ClinicalTrials.gov — it is not a negative signal.

How this score is built

Investigator standing0/100
No investigator recorded in the registry for this trial

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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.

Vaginal dysbiosis characterized by reduced relative abundance of Lactobacillus species has been associated with reproductive outcomes in women undergoing frozen embryo transfer (FET). This study evaluates the safety, tolerability, and molecular effects of FB301 in women undergoing FET who have no known underlying clinical gynecological conditions but are identified as having molecular dysbiosis by metagenomic sequencing of a vaginal swab collected at screening. Participants will be randomized to one of three arms: (1) FB301 following a single initial vaginal cleansing with chlorhexidine (an antiseptic solution), (2) FB301 following a single sham cleansing with saline, or (3) placebo following sham cleansing. Cleansing occurs once prior to initiation of study treatment. Participants will then receive 15 days of study treatment during a mock frozen embryo transfer (FET) cycle in which participants receive hormonal preparation of the endometrium but no embryo is transferred. Following completion of the mock cycle, participants will proceed with their planned frozen embryo transfer during the subsequent menstrual cycle, in accordance with standard clinical practice. Participants who become pregnant will be followed until birth. The primary objective is to evaluate whether treatment increases the proportion of participants achieving a predefined Lactobacillus-dominant vaginal bacterial profile following therapy. Secondary objectives include evaluation of biochemical pregnancy (confirmed by serum beta-hCG testing) and clinical pregnancy (confirmed by transvaginal ultrasound) following the subsequent planned FET cycle.

Conditions

Vaginal Dysbiosis

Eligibility

Eligibility
Sex	Female
Ages	18 Years – 40 Years
Healthy volunteers	No

Eligibility as written in the registry

Inclusion Criteria: 1. Able to understand the study and sign a consent form. 2. Is a woman aged 18 to 40 years. 3. Still has regular menstrual periods (pre-menopausal). 4. 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. 5. Planning to have a frozen embryo transfer (FET) using one good-quality embryo (grade 3BB or higher) and are considered medically suitable to proceed. 6. Willing to have only one embryo transferred during the study cycle. 7. A vaginal swab taken at the first study visit shows a specific vaginal microbiome imbalance required for this study (vaginal molecular dysbiosis). 8. An ultrasound scan shows no problems with uterus or pelvis that would prevent pregnancy or greatly reduce the chance of pregnancy. 9. Recent fertility blood tests (within the last 6 months) show: * FSH less than 12 IU/L * AMH greater than 1 ng/mL 10. Body mass index (BMI) is between 18 and 38 kg/m². 11. From the first study treatment until the mock FET cycle, agrees to: * Avoid vaginal intercourse or use condoms (without spermicide or lubricant), * Avoid swimming or hot tubs, * Avoid using tampons, menstrual cups, sex toys, vaginal cleansers, lubricants, or other vaginal products unless approved by the study team. 12. Willing to answer questions about sexual and reproductive activity during the study. 13. Willing to provide vaginal swab samples at the clinic. 14. Willing to receive the first study treatment in the clinic and use the study treatment at home as instructed. 15. Screening blood tests are negative for hepatitis B, hepatitis C, HIV, and syphilis. 16. Willing to attend all study visits and follow-up assessments and provide information about pregnancy and newborn health outcomes. Exclusion Criteria: 1. History of three or more failed frozen embryo transfers (FET) in the past 3 years. 2. Have a condition that weakens the immune system (such as uncontrolled diabetes, active cancer, or an organ transplant). 3. Currently taking medications that suppress the immune system (such as systemic steroids, biologics, chemotherapy, or transplant medications). 4. Is already pregnant before completing the mock FET cycle. 5. Test positive for a sexually transmitted infection (such as chlamydia, gonorrhea, Mycoplasma genitalium, or Trichomonas vaginalis). 6. Current vaginal yeast infection that requires treatment. 7. YCannot safely take the hormone medications required for a frozen embryo transfer (such as estradiol or progesterone). 8. Use of intravaginal progesterone gels or solutions. 9. Needs regular antibiotics or are likely to require antibiotics during the study. 10. Has taken oral, injectable, or vaginal antibiotics within 30 days before screening. 11. History of gynecological cancer or other significant gynecological condition that would make participation unsafe. 12. Has a medical condition that would make participation unsafe or difficult. 13. Has an unstable medical or psychiatric condition that could make it difficult to follow study requirements. 14. Has any other condition that could interfere with participation.

Eligibility in plain statements

This record's criteria have not been broken into separate statements yet. The registry text above is complete and is the authoritative version.

Study design

Study design
Study type	Interventional
Phase	Phase 2
Allocation	Randomised
Intervention model	PARALLEL
Primary purpose	TREATMENT
Masking	TRIPLE (3)
Enrolment	30 participants sought

Sponsor and collaborators

Freya Biosciences ApS Sponsor
Premier Research Collaborators

Arms and interventions

FB301 / ChlorhexidineEXPERIMENTAL
FB301 / ShamEXPERIMENTAL
Placebo / ShamPLACEBO_COMPARATOR

Interventions

Other Chlorhexidine (0.5%) Vaginal Cleanse
Vaginal cleanse with 0.5% Chlorhexidine solution prior to first IP administration
Drug FB-301
FB301 capsule
Drug Placebo
FB301 Placebo capsule
Other Sham vaginal cleanse (saline)
Vaginal cleanse with saline solution prior to first IP administration.

Outcome measures

Primary outcome
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.
Metagenomic sequencing is performed on cervical vaginal swab samples. Relative abundance is expressed as a percentage of bacterial sequencing reads that are assigned to a specific bacterial species.
Time frame Baseline to Day 16 (Mock FET cycle)
Secondary outcome
Percentage change from baseline in relative abundance of Lactobacillus crispatus, L. jensenii, L. mulieris, L. gasseri, and L. paragasseri as measured by metagenomic sequencing.
Metagenomic sequencing is performed on cervical vaginal swab samples. Relative abundance is expressed as a percentage of bacterial sequencing reads that are assigned to a specific bacterial species.
Time frame Baseline to Day 16 (Mock FET cycle)
Secondary outcome
Biochemical pregnancy rate following frozen embryo transfer (FET), defined as a positive serum beta-human chorionic gonadotropin (hCG) test.
Time frame 12-14 days after frozen embryo transfer (FET)
Secondary outcome
Clinical pregnancy rate following frozen embryo transfer (FET), defined as the presence of a fetal heartbeat confirmed by transvaginal ultrasound.
Time frame 5-6 weeks after frozen embryo transfer (FET)
Secondary outcome
Frequency and intensity of all treatment-emergent adverse events (TEAEs), adverse events (AEs), serious adverse events (SAEs), and adverse events of special interest) AESI
Time frame Baseline to End of Study (up to neonatal follow-up assessment (Visit 11), approximately 10 months after FET)
Secondary outcome
The incidence of early pregnancy loss, defined as a positive beta-hCG test (biochemical pregnancy) at 12-14 days after FET but no transvaginal ultrasound-confirmed fetal heartbeat at 5-6 weeks after FET (Visit 7)
Time frame 5-6 weeks after FET

Dates

Dates
Start date	July 22, 2026 (actual)
Primary completion	October 31, 2026 (estimated)
Completion	September 30, 2027 (estimated)
First posted	March 5, 2026 (actual)
Last updated	September 3, 2026
Results posted	Not stated in the registry record
Status last verified	September 2026

Actual means the event happened. Estimated means the sponsor expects it. The two mean different things.

Locations

2 sites are recruiting

United States

United States
Facility	City	State or region	Status
REACH Fertility	Charlotte	North Carolina	Not yet recruiting
Delta Hy Research LLC / Advanced Fertility Texas	Houston	Texas	Recruiting
Boston IVF	Waltham	Massachusetts	Not yet recruiting
Cypress Medical Research Centre	Wichita	Kansas	Recruiting

Study documents

No documents are linked in this registry record.

Changes over time

September 3, 2026
Status changed
Status changed from Not yet recruiting to Recruiting
NOT_YET_RECRUITINGRECRUITING
September 3, 2026
Recruitment opened
Recruitment opened
NOT_YET_RECRUITINGRECRUITING
September 3, 2026
Site added
3 sites added (4 total)
14

Registry: ClinicalTrials.gov · NCT########

https://xmedica.io/trials/ctgov/NCT07453069

Categories

Registered in 1 registry

Interested in this study?

How this study is set up

Summary

Conditions

Eligibility

Eligibility as written in the registry

Eligibility in plain statements

Study design

Sponsor and collaborators

Arms and interventions

Interventions

Outcome measures

Dates

Locations

United States

Study documents

Changes over time