Skip to content
Clinical Trials – home
Recruiting

Study of chlorhexidine, metronidazole, and FB301 for the treatment of women with bacterial vaginosis

Verified siteRegistered drug
Clinical Trials Concierge

Prefer not to search? Our Concierge searches the trials for you.

What is this trial about?

A plain-language summary of the goals, design and what participants do

This study is being conducted to evaluate the effect of certain treatments on the vaginal microbiome, which is the community of tiny organisms living in the vagina, in women diagnosed with Bacterial vaginosis. This condition occurs when there is an imbalance of the natural bacteria in the vagina. The research focuses on how different combinations of medications can help restore a healthy balance of beneficial bacteria.

The treatments involved include chlorhexidine, which is applied as a liquid solution, and metronidazole, which is taken as a pill. Following these initial treatments, the study uses a product known as FB301, which is provided in the form of a capsule. The goal is to see if using these medications together can increase the presence of healthy bacteria like Lactobacillus species.

During the study, participants will follow a specific sequence of using the different medications. Over several weeks, the changes in the vaginal environment will be monitored to determine if the treatments successfully restore a healthy microbial balance and resolve symptoms associated with the condition.

The research process

The trial runs in 3 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Initial treatment phase

    During the first stage, chlorhexidine (a liquid for vaginal use) or metronidazole (a tablet taken by mouth) is used as a pre-treatment.

    The metronidazole dosage is 1000 mg administered orally.

    The chlorhexidine dosage is 30 ml administered for vaginal use.

  2. Step 2

    Fb301 administration

    After the pre-treatment, fb301 is administered via hard vaginal capsules.

    Each capsule contains 10 million colony forming units, which is a measurement of the number of live bacteria in the medicine.

  3. Step 3

    Monitoring and follow-up

    vaginal samples are collected at week 3, week 5, week 7, and week 10 to monitor changes in the vaginal microbiome, which refers to the collection of microorganisms living in the vagina.

    The vaginal samples are used to check for microbiological cure and clinical cure, which involves assessing the resolution of abnormal discharge and checking the ph level and the presence of clue cells (cells that indicate bacterial vaginosis).

Who can join the trial?

13 criteria

  • Women between the ages of 18 and 45 who have not yet gone through menopause, which is the natural end of monthly menstrual periods.
  • Women who have bacterial vaginosis, an imbalance of the natural bacteria in the vagina, which must be confirmed by a doctor using a Gram stain (a test that looks at bacteria under a microscope) showing a Nugent Score (a specific measurement of bacterial imbalance) of 7 or higher.
  • Symptoms must include vaginal discharge or a fishy odor.
  • Women must be willing to follow all study steps, including cleaning the vagina, taking the study medicine, and attending all scheduled appointments.
  • Women must agree to avoid vaginal intercourse (sexual activity involving the vagina) and the use of products like tampons, menstrual cups, sex toys, spermicides (substances that kill sperm), or lubricants from the first treatment until 17 days after the treatment starts.
  • Women must be in good physical and mental health as decided by the doctor.
  • A Body Mass Index (BMI), which is a measure of body fat based on height and weight, must be 37 or less.
  • Women must have regular periods or have not had a period for at least 3 months due to specific types of birth control.
  • Women must agree to follow strict rules regarding contraception (methods used to prevent pregnancy). This means if you use birth control like pills, patches, or injections, you cannot change your method during the study. If you do not use birth control, you cannot start a new method during the study, but you must use condoms after the initial 17-day period.
  • Women must be willing to answer questions about their sexual activity and products used in the vagina.
  • Women must be able and willing to collect their own vaginal samples at home or at the clinic for testing.
  • Women must be able to sign a legal document called informed consent, which means they understand and agree to all the rules and details of the study.
  • There must be no recent changes in your medical health or other treatments you are receiving.

Who cannot join the trial?

25 criteria

  • Having a known immunodeficiency, which is a condition where the body's immune system cannot protect the body properly from infection.
  • Taking any prescription drugs, over-the-counter medicines, vitamins, or herbal supplements within a specific timeframe before the study begins, unless the study doctor decides they are safe to use.
  • Using any investigational drugs, which are medicines currently being studied in clinical trials, unless the previous study ended at least 30 days ago.
  • Using antibiotics (medicines that fight bacteria) through a pill or a vaginal application within the last 30 days.
  • Receiving any current antibacterial therapy (treatment to kill bacteria) that is not related to bacterial vaginosis.
  • Having clinical laboratory test results that are not considered healthy or acceptable, such as abnormal urinalysis (urine test), chemistry (blood tests that measure substances like sugar or salt), or hematology (tests that look at blood cells).
  • Testing positive for HBsAg (a marker for Hepatitis B), HCV (Hepatitis C virus), or HIV (a virus that attacks the immune system).
  • Testing positive for Treponema pallidum, which is the bacteria that causes syphilis (a sexually transmitted infection).
  • Having blood pressure or pulse rate (heart rate) levels that are considered abnormal by the study doctor.
  • Having an aural body temperature (temperature taken through the ear) that is lower than 35.5°C or higher than 37.6°C.
  • Being pregnant, breastfeeding, having been pregnant within the last 2 months, or planning to become pregnant within the next 6 months.
  • Participating in egg donation during the study.
  • Having an allergy or a medical reason why you cannot use metronidazole or chlorhexidine.
  • Using a copper IUD (a small device placed in the uterus for birth control) within the last 12 weeks.
  • Using probiotics, prebiotics, or symbiotics (products used to add healthy bacteria to the body) orally or vaginally within the last 30 days, though eating yogurt with live cultures is allowed.
  • Donating whole blood or plasma (the liquid part of blood) within specific time limits before or during the study.
  • Having a history of alcohol or substance dependency, which means a regular and uncontrollable need to use alcohol or drugs.
  • Being an employee of the companies or organizations conducting the study.
  • Any other health or social condition that the doctor believes would make it difficult to follow the study rules or interfere with the results.
  • Testing positive for alcohol or drugs of abuse on the first day of receiving the study treatment.
  • Having a medical condition that requires you to take antibiotics on a regular basis.
  • Having a history of gynecological cancers (cancers of the female reproductive system) or other reproductive health issues that prevent participation.
  • Having abnormal findings during a physical examination or gynecological examination (a check-up of the reproductive organs).
  • Having other types of infections like candidiasis (a yeast infection), Trichomonas vaginalis, Chlamydia, Gonorrhea, or active Herpes.
  • Having any other vaginal or vulvar (the area around the vagina) conditions that might make it hard to see if the study treatment is working.
Clinical Trials Concierge

Prefer not to search? Our Concierge searches the trials for you.

Tell us about your condition – we search every trial in Europe and connect you with the right site.

We usually reply within a few days

Verified sites

All sites with verified contact details – recruitment status may not be available; ask directly

Trial locations

Where you can join this trial

Countries are shaded by recruitment status. Click a recruiting country to ask about joining there.

Recruiting
Not finding your country?

Not sure what to do next?

Joining a clinical trial can seem overwhelming. We guide you step by step, so you know exactly what to expect and how we support you through the process.

See the full process and FAQ

Investigated drugs

  • Chlorhexidine

    is a liquid applied to the vaginal area to help clean and kill harmful bacteria.

  • Metronidazole

    is a pill taken by mouth to fight the bacteria that cause infections.

  • FB301

    is a vaginal capsule containing beneficial bacteria used to help restore a healthy balance of natural bacteria in the vagina.

What is already known about the treatment

  • Chlorhexidine gluconate

    This antiseptic is applied as a liquid solution directly to the vaginal area. It is a well-established medication widely used in medical settings to kill various types of germs. It works by breaking down the outer layer of bacteria, which causes them to die. It is classified as an antiseptic agent.

  • Metronidazole

    This medication is taken by mouth in the form of a swallowed tablet. It is a commonly used antibiotic frequently prescribed to treat infections caused by specific bacteria and parasites. It works at a molecular level by damaging the DNA of the germs, preventing them from growing and multiplying. It is classified as an antibiotic.

  • FB301

    This product is administered as a hard capsule inserted into the vagina. It is a specialized treatment consisting of beneficial live bacteria, currently being studied for its ability to restore healthy balance to the vaginal environment. It works by introducing helpful microorganisms that compete with harmful bacteria to maintain a healthy ecosystem. It is classified as a probiotic.

Investigated diseases

Bacterial vaginosis - This condition occurs when there is an imbalance of the natural bacteria found in the vagina. It happens when the healthy bacteria that maintain a stable environment are replaced by an overgrowth of other types of bacteria. This shift causes a change in the vaginal microbiome and its chemical balance. The condition is characterized by a decrease in beneficial bacteria and an increase in various other microorganisms. As it progresses, the microbial community becomes increasingly dominated by different bacterial species.
Trial detailsLast updated 2 Oct 2026
Age18+ yearsPhasePhase IITrial ID2025-524362-20-00Protocol codeFRB-004Estimated enrolment120 patientsSponsorFreya Biosciences ApS

sourced from the EU Clinical Trials Register and site verification

Want to learn more about this trial or check if you can participate?

Clinical Trials Concierge

Prefer not to search? Our Concierge searches the trials for you.

Tell us about your condition – we search every trial in Europe and connect you with the right site.

Legal notice · Published by CTIN POLAND sp. z o.o., ul. rtm. Witolda Pileckiego 67/109, 02-781 Warsaw, Poland · KRS 0001111334 · REGON 528919042 · NIP 9512598637

© 2026 Clinical Trials EU – European Clinical Trials Information Network

GDPR compliance, ISO 9001 and ISO 27001 certified (LL-C Certification)

On this site, “treatment” means an investigational medicine being studied in a clinical trial. Its safety and efficacy for the use being studied have not yet been confirmed, some participants may receive a placebo or a comparator medicine, and taking part does not guarantee any health benefit. The decision to take part is made by the doctor at the research site. This site is for information only and does not replace medical advice.

This service is not affiliated with the European Commission, the EMA, or the official CTIS system. Most information comes from publicly available international clinical-trial registries, supplemented by data from academic sites, national regulators and commercial sponsors. On this site, “treatment” and “therapy” mean a medicine being tested in a clinical trial. Its safety and effectiveness in the use being studied are not yet confirmed, some participants may receive a placebo or a comparator, and taking part does not guarantee a health benefit. The doctor at the research site decides who can take part. This site provides information, not medical advice. Certain content and visual elements on this website have been generated or enhanced using artificial intelligence (AI).