Vaginal DysbiosisPhase 2NCT07453069
Effect of FB301 on Vaginal Bacterial Profile in Women With Asymptomatic Vaginal Dysbiosis Undergoing a Mock Frozen Embryo Transfer Cycle
A Phase 2 study testing FB-301 and Chlorhexidine (0.5%) Vaginal Cleanse in people with Vaginal Dysbiosis, run by Freya Biosciences ApS at 4 sites in United States.
Trial 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 45 years with a prior failed FET and a defined vaginal bacterial imbalance (dysbiosis). Read more about this study
- Who is it for?
- Ages 18 to 45 years, women only
- Conditions the study is for
- Vaginal Dysbiosis
- What is being tested?
- FB-301 and Chlorhexidine (0.5%) Vaginal Cleanse
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 30 participants
- Where
- 4 sitesUnited States
- Study dates
- 22 Jul 2026to 30 Sep 2027
- Phase
- Phase 2
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 45 years
- Women only
- No healthy volunteers
- Adult
Who may be able to join
- Able to understand the study and sign a consent form.
- Is a woman aged 18 to 45 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.
- Willing to take part in mock frozen embryo transfer (FET) cycle and is considered medically suitable to subsequently have a frozen embryo transfer (FET) using one good-quality embryo (grade 3BB or higher).
- Willing to have only one embryo transferred during the study cycle.
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- 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.
- Recent fertility blood tests show FSH less than 12 IU/L (within the last 6 months)
- Recent fertility blood tests show AMH greater than 1 ng/mL (at the time of oocyte retrieval).
- Body mass index (BMI) is between 18 and 42 kg/m².
- 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.
- Willing to answer questions about sexual and reproductive activity during the study.
- Willing to provide vaginal swab samples at the clinic.
- Willing to receive the first study treatment in the clinic and use the study treatment at home as instructed.
- Screening blood tests are negative for hepatitis B, hepatitis C, HIV, and syphilis.
- Willing to attend all study visits and follow-up assessments and provide information about pregnancy and newborn health outcomes.
Who cannot join
- History of five or more failed frozen embryo transfers (FET) in the past 5 years.
- Have a condition that weakens the immune system (such as uncontrolled diabetes, active cancer, or an organ transplant).
- Currently taking medications that suppress the immune system (such as systemic steroids, biologics, chemotherapy, or transplant medications).
- Is already pregnant before completing the mock FET cycle.
- Test positive for a sexually transmitted infection (such as chlamydia, gonorrhea, Mycoplasma genitalium, or Trichomonas vaginalis).
- Current vaginal yeast infection that requires treatment.
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- Cannot safely take the hormone medications required for a frozen embryo transfer (such as estradiol or progesterone).
- Use of intravaginal progesterone gels or solutions.
- Needs regular antibiotics or are likely to require antibiotics during the study.
- Has taken oral, injectable, or vaginal antibiotics within 30 days before screening.
- History of gynecological cancer or other significant gynecological condition that would make participation unsafe.
- Has a medical condition that would make participation unsafe or difficult.
- Has an unstable medical or psychiatric condition that could make it difficult to follow study requirements.
- Has any other condition that could interfere with participation.
Trial locations and contacts
4 sites in 1 country. Contact the study team or a site near you to ask about taking part.
United States4 sites, 4 recruiting
- Recruiting
REACH Fertility
Charlotte, North Carolina, 28207
Patrick McPhillips, 704-343-4440, Patrick.McPhillips@NorthCarolinaFertility.com
- Recruiting
Delta Hy Research LLC / Advanced Fertility Texas
Houston, Texas, 77079
David Leiman, MD, MBA, 713-894-4840, dleiman@dhclinical.com
Harold Minkowitz, MD, 713 480 3028, hminkowitz@dhclinical.com
- Not yet recruiting
Boston IVF
Waltham, Massachusetts, 02451
Kristin Rooney, 781-434-6470, krooney@bostonivf.com
Nina Resetkova, MD, MBA
- Recruiting
Cypress Medical Research Centre
Wichita, Kansas, 67226
Bryan S Baker, RN, MSM, CCRC, 312 214 3690, bryan@cypressmrc.com
About this study
Official title: 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 18-45 Years of Age With Asymptomatic Vaginal Molecular Dysbiosis Planning to Undergo a Frozen Embryo Transfer (FET) Cycle
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 45 years with a prior failed FET and a defined vaginal bacterial imbalance (dysbiosis).
The main question it aims to answer is:
Read more
- 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 may 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
- Subsequently complete a mock FET cycle before proceeding with their planned frozen embryo transfer cycle
Participants who become pregnant will be followed-up until birth.
Read the detailed description
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 may proceed with their planned frozen embryo transfer during a 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
- Being tested
- FB-301, Placebo, Chlorhexidine (0.5%) Vaginal Cleanse, Sham vaginal cleanse (saline)
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
FB-301Drug
FB301 capsule
PlaceboDrug
FB301 Placebo capsule
Chlorhexidine (0.5%) Vaginal CleanseOther
Vaginal cleanse with 0.5% Chlorhexidine solution prior to first IP administration
Sham vaginal cleanse (saline)Other
Vaginal cleanse with saline solution prior to first IP administration.
| Study group | Role | What they receive |
|---|---|---|
| FB301 / Chlorhexidine | Experimental | Not described Receives: Drug: FB-301; Other: Chlorhexidine (0.5%) Vaginal Cleanse |
| FB301 / Sham | Experimental | Not described Receives: Drug: FB-301; Other: Sham vaginal cleanse (saline) |
| Placebo / Sham | Placebo comparator | Not described Receives: Drug: Placebo; Other: Sham vaginal cleanse (saline) |
What is being measured
The primary outcome is the main question the study is designed to answer.
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.
Measured: Baseline to Day 16 (Mock FET cycle)
Secondary outcomes (5)
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.
Measured: Baseline to Day 16 (Mock FET cycle)
Biochemical pregnancy rate following frozen embryo transfer (FET), defined as a positive serum beta-human chorionic gonadotropin (hCG) test.
Measured: 12-14 days after frozen embryo transfer (FET)
Clinical pregnancy rate following frozen embryo transfer (FET), defined as the presence of a fetal heartbeat confirmed by transvaginal ultrasound.
Measured: 5-6 weeks after frozen embryo transfer (FET)
Frequency and intensity of all treatment-emergent adverse events (TEAEs), adverse events (AEs), serious adverse events (SAEs), and adverse events of special interest) AESI
Measured: Baseline to End of Study (up to neonatal follow-up assessment (Visit 11), approximately 10 months after FET)
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)
Measured: 5-6 weeks after FET
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted5 Mar 2026
- Study start22 Jul 2026
- Primary completion31 Oct 2026 (estimated)
- Study completion30 Sep 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Vaginal DysbiosisStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 2
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Triple blind
- Who is masked
- Participant, Investigator, Outcomes assessor
- Enrolment
- 30 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Freya Biosciences ApS
- Sponsor type
- Industry (pharma, biotech, devices)
- Collaborators
- Premier Research
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07453069
- Sponsor's protocol ID
- FRB-005
- Status last verified
- Oct 2026
- First submitted
- 26 Feb 2026
- Last updated
- 15 Oct 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- No: There are no current plans to share individual participant data.
Study at a glance
From the registry record, last updated by the sponsor on 15 Oct 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- 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 18-45 Years of Age With Asymptomatic Vaginal Molecular Dysbiosis Planning to Undergo a Frozen Embryo Transfer (FET) Cycle
- ClinicalTrials.gov ID
- NCT07453069
- Acronym / sponsor ID
- FRB-005
- Conditions
- Vaginal Dysbiosis
- Phase
- Phase 2
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 30 participants (estimated)
- Lead sponsor
- Freya Biosciences ApSIndustry (pharma, biotech, devices)
- Collaborators
- Premier Research
- Study start
- 22 Jul 2026 (actual)
- Primary completion
- 31 Oct 2026 (estimated)
- Study completion
- 30 Sep 2027 (estimated)
- First posted
- 5 Mar 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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 45 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 may 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
- Subsequently complete a mock FET cycle before proceeding with their planned frozen embryo transfer cycle
Participants who become pregnant will be followed-up until birth.
Detailed description
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 may proceed with their planned frozen embryo transfer during a 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.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Triple blind (participant, investigator, outcomes assessor)
- Number of arms
- 3
| Arm | Type | Receives |
|---|---|---|
| FB301 / Chlorhexidine | Experimental | Drug: FB-301, Other: Chlorhexidine (0.5%) Vaginal Cleanse |
| FB301 / Sham | Experimental | Drug: FB-301, Other: Sham vaginal cleanse (saline) |
| Placebo / Sham | Placebo comparator | Drug: Placebo, Other: Sham vaginal cleanse (saline) |
Who may qualify
- Ages
- 18 to 45 years
- Sex
- Female only
- Healthy volunteers
- Not accepted
- Age groups
- Adult
Key inclusion criteria (20 listed)
- Able to understand the study and sign a consent form.
- Is a woman aged 18 to 45 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.
- Willing to take part in mock frozen embryo transfer (FET) cycle and is considered medically suitable to subsequently have a frozen embryo transfer (FET) using one good-quality embryo (grade 3BB or higher).
Key exclusion criteria (14 listed)
- History of five or more failed frozen embryo transfers (FET) in the past 5 years.
- Have a condition that weakens the immune system (such as uncontrolled diabetes, active cancer, or an organ transplant).
- Currently taking medications that suppress the immune system (such as systemic steroids, biologics, chemotherapy, or transplant medications).
- Is already pregnant before completing the mock FET cycle.
- Test positive for a sexually transmitted infection (such as chlamydia, gonorrhea, Mycoplasma genitalium, or Trichomonas vaginalis).
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| FB-301FB301 capsule | Drug | FB301 / Chlorhexidine, FB301 / Sham |
| PlaceboFB301 Placebo capsule | Drug | Placebo / Sham |
| Chlorhexidine (0.5%) Vaginal CleanseVaginal cleanse with 0.5% Chlorhexidine solution prior to first IP administration | Other | FB301 / Chlorhexidine |
| Sham vaginal cleanse (saline)Vaginal cleanse with saline solution prior to first IP administration. | Other | FB301 / Sham, Placebo / Sham |
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.
Time frame: Baseline to Day 16 (Mock FET cycle)
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.
5 secondary outcomes
Percentage change from baseline in relative abundance of Lactobacillus crispatus, L. jensenii, L. mulieris, L. gasseri, and L. paragasseri as measured by metagenomic sequencing.
Time frame: Baseline to Day 16 (Mock FET cycle)
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)
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)
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)
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
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 15 Oct 2026.
- Individual participant dataSharing planned: No. There are no current plans to share individual participant data.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
4 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 2 study testing FB-301 and Chlorhexidine (0.5%) Vaginal Cleanse in people with Vaginal Dysbiosis, run by Freya Biosciences ApS at 4 sites in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 20 inclusion and 14 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 15 Oct 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 4 sites in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Each site lists its own contact: choose the nearest one under Trial locations. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
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. (time frame: Baseline to Day 16 (Mock FET cycle)). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 15 Oct 2026.