#1 Clinical Trials Search in Europe

Estriol

This article examines the use of estriol, a form of estrogen, in various clinical trials. Estriol is being studied for its potential benefits in treating vaginal atrophy, improving vaginal health, and addressing other conditions in postmenopausal women and women with certain medical conditions. The trials explore different formulations, dosages, and applications of estriol to determine its efficacy and safety.

Table of Contents

What is Estriol?

Estriol, also known as E3, is a type of estrogen hormone. It is one of the three main estrogens produced naturally in the body, alongside estradiol and estrone. Estriol is particularly important during pregnancy, as it is produced in large amounts by the placenta[1]. In medical treatments, estriol is often used as a synthetic hormone therapy, especially for postmenopausal women[2].

Estriol is sometimes referred to by its chemical names, including 16α-hydroxyestradiol or estra-1,3,5(10)-triene-3,16α,17β-triol[3]. These technical names describe its molecular structure, but for most patients, it’s simply known as estriol.

Medical Uses of Estriol

Estriol is primarily used to treat various conditions related to estrogen deficiency. Its main applications include:

  • Vaginal Atrophy: This is a condition where the vaginal walls become thin, dry, and inflamed due to a lack of estrogen. Estriol helps to improve the health and function of vaginal tissues[2][4].
  • Vulvovaginal Atrophy: Similar to vaginal atrophy, this condition affects both the vagina and vulva. Estriol can help alleviate symptoms such as dryness, itching, and pain during intercourse[2].
  • Urogenital Symptoms: Estriol may help with urinary symptoms like frequent urination or urinary tract infections that can occur after menopause[5].
  • Pelvic Organ Prolapse: Some studies are investigating whether estriol can help improve outcomes in surgeries for pelvic organ prolapse[6].
  • Multiple Sclerosis: Research is ongoing to determine if estriol might have beneficial effects for people with relapsing-remitting multiple sclerosis[5][7].

How is Estriol Administered?

Estriol is typically administered in the following ways:

  • Vaginal Gel or Cream: This is the most common form for treating vaginal atrophy. The gel or cream is inserted into the vagina using an applicator[2][4].
  • Oral Tablets: In some cases, estriol may be given as pills to be taken by mouth[7].
  • Vaginal Suppositories: These are solid forms of the medication that are inserted into the vagina where they melt and release the drug[8].

The dosage and frequency of application can vary depending on the specific condition being treated and the form of estriol being used. For vaginal treatments, a common regimen involves daily application for the first few weeks, followed by a reduced frequency (such as twice weekly) for maintenance[4][2].

Effectiveness of Estriol

Clinical trials have shown that estriol can be effective in treating various conditions:

  • Vaginal Health: Estriol has been shown to improve vaginal health by increasing the maturation of vaginal cells, lowering vaginal pH (making it more acidic, which is healthier), and reducing symptoms like dryness and irritation[2][4][2].
  • Sexual Function: By improving vaginal health, estriol can help reduce pain during intercourse (dyspareunia) and improve overall sexual function in postmenopausal women[8].
  • Urinary Symptoms: Some studies suggest that estriol may help with urinary symptoms associated with menopause[5].
  • Multiple Sclerosis: Research is ongoing, but some studies have shown promising results in using estriol to reduce relapse rates in multiple sclerosis[5][7].

Potential Side Effects and Safety Considerations

While estriol is generally considered to have a good safety profile, especially when used vaginally, there are some potential side effects and considerations:

  • Local Irritation: Some women may experience local irritation or discomfort when using vaginal estriol products[4].
  • Hormonal Effects: Although less potent than other forms of estrogen, estriol can still have systemic effects. This is particularly important for women with a history of certain cancers[2].
  • Endometrial Safety: In some cases, estrogen therapy may increase the risk of endometrial hyperplasia (overgrowth of the uterine lining). However, vaginal estriol appears to have a lower risk compared to other forms of estrogen[2].
  • Breast Cancer Considerations: The safety of estriol in women with a history of breast cancer is still being studied. Some research is looking at very low doses of estriol for these patients[1].

It’s important to discuss any potential risks with your healthcare provider before starting estriol treatment.

Ongoing Research and Future Potential

Estriol continues to be the subject of ongoing research:

  • Multiple Sclerosis: Studies are investigating whether estriol, when combined with other MS treatments, can reduce relapse rates and slow disease progression[5][7].
  • Low-Dose Formulations: Researchers are exploring the effectiveness of very low-dose estriol formulations, which may provide benefits while minimizing potential risks[4][2].
  • Pelvic Floor Disorders: Some studies are looking at whether estriol treatment before pelvic floor surgery can improve outcomes[6].
  • Vaginal Health in Cancer Survivors: Research is ongoing to determine safe and effective ways to use estriol in women with a history of hormone-sensitive cancers[1].

As research continues, our understanding of estriol’s potential uses and effects may expand, potentially leading to new treatments and applications in the future.

Aspect Details
Primary Uses Treatment of vaginal atrophy, improving vaginal health in postmenopausal women
Formulations Vaginal gels, creams, suppositories
Dosages Concentrations ranging from 0.0008% to 0.005%, typically applied daily or 2-3 times per week
Duration of Trials Most trials last 12 weeks, some extending to 6 months or longer
Key Outcomes Measured Vaginal pH, cell maturation, symptom severity, quality of life, hormone levels
Special Populations Postmenopausal women, breast cancer patients on aromatase inhibitors, women with pelvic organ prolapse
Safety Considerations Monitoring of systemic absorption, endometrial effects, use in women with history of breast cancer
Additional Applications Potential benefits in multiple sclerosis, preparation for vaginal surgery

FAQ

  • What is estriol and what is it being studied for? Estriol is a form of estrogen that is being studied in clinical trials for treating vaginal atrophy, improving vaginal health, and addressing symptoms like vaginal dryness and pain during intercourse in postmenopausal women. It's also being explored for potential benefits in conditions like multiple sclerosis and pelvic organ prolapse.
  • How is estriol typically administered in these trials? In most trials, estriol is administered vaginally as a gel, cream, or suppository. Common dosages range from 0.0008% to 0.005% concentration, applied daily or a few times per week depending on the study protocol.
  • What are some of the main outcomes being measured in estriol trials? Key outcomes include changes in vaginal pH, maturation of vaginal cells, severity of vaginal dryness and other symptoms, changes in vaginal health indexes, quality of life measures, and safety assessments including monitoring hormone levels.
  • Are there any safety concerns with using estriol vaginally? While generally considered safer than systemic hormone therapy, researchers are still evaluating the safety of vaginal estriol, particularly in women with a history of breast cancer. Some trials are specifically looking at hormone levels and endometrial effects to assess safety.
  • How long do most of the estriol clinical trials last? The duration of estriol trials varies, but many last around 12 weeks, with some extending to 6 months or longer to assess longer-term effects and safety. Some trials also include follow-up periods after treatment ends.

Ongoing Clinical Trials on Estriol

  • Study on Improving Sexual Health and Quality of Life in Cervical Cancer Patients Using Estriol, Estradiol Hemihydrate, and Promestriene

    Recruiting

    1 1 1 1
    Investigated drugs:
    Spain

  • Study on the Effectiveness of Platelet-Rich Plasma and Hyaluronic Acid vs. Estriol for Women with Menopausal Genitourinary Syndrome

    Recruiting

    1 1 1 1
    Investigated diseases:
    Investigated drugs:
    Spain

  • Study on Estriol Vaginal Ring for Treating Vaginal Atrophy in Postmenopausal Women

    Not recruiting

    1
    Investigated drugs:
    Germany

  • Comparison of estriol, prasterone and estriol with lactobacillus for vulvovaginal atrophy in breast cancer patients on endocrine therapy

    Not recruiting

    1 1 1 1
    Investigated diseases:
    Investigated drugs:
    Belgium

Glossary

  • Estriol: A form of estrogen that is weaker than estradiol and estrone. It is being studied for its potential benefits in treating vaginal atrophy and other conditions.
  • Vaginal atrophy: Thinning, drying and inflammation of the vaginal walls due to lower estrogen levels, typically occurring after menopause.
  • Maturation Value (MV): A cytologic parameter indicative of the degree of maturation of the vaginal mucosa, calculated based on the proportion of different cell types.
  • Dyspareunia: Pain during sexual intercourse, often a symptom of vaginal atrophy in postmenopausal women.
  • Aromatase inhibitors: A class of drugs used in breast cancer treatment that lower estrogen levels in the body.
  • Vaginal Health Index (VHI): A clinical assessment tool used to evaluate vaginal health based on factors like elasticity, fluid volume, pH, and epithelial integrity.
  • Pelvic organ prolapse: A condition where one or more pelvic organs drop from their normal position, often treated with surgery in severe cases.
  • Follicle Stimulating Hormone (FSH): A hormone that stimulates the growth of ovarian follicles. Its levels are often measured to assess menopausal status and ovarian function.
  • Vulvovaginal atrophy: Changes in the vagina and vulva due to decreased estrogen, leading to symptoms like dryness, burning, and irritation.
  • Topical estrogen therapy: The application of estrogen directly to the vagina in the form of creams, gels, or suppositories to treat local symptoms.

References

  1. https://clinicaltrials.gov/study/NCT02413008
  2. https://clinicaltrials.gov/study/NCT02967510
  3. https://clinicaltrials.gov/study/NCT04574999
  4. https://clinicaltrials.gov/study/NCT04159493
  5. https://clinicaltrials.gov/study/NCT03774407
  6. https://clinicaltrials.gov/study/NCT06391372
  7. https://clinicaltrials.gov/study/NCT00451204
  8. https://clinicaltrials.gov/study/NCT03116022