The goal of this pilot trial is to learn if a novel non-hormonal treatment, metformin hydrochloride, works to treat pelvic pain in young women with endometriosis. The main questions it aims to answer are: * Is metformin superior to placebo in alleviating pain symptoms in young women with endometriosis? * Does metformin alter systemic inflammatory markers over 6 months in young women with endometriosis? Researchers will compare metformin to a placebo (a look-alike substance that contains no drug) to see if metformin works to treat pelvic pain. Participants will: * Take drug metformin or a placebo every day for 6 months * Visit the clinic three times: once at baseline (pre-treatment), once at 3 months, and once at 6 months * Keep a daily symptom diary to track pain, bleeding, and usage of any pain medications
Endometriosis is a chronic illness defined by the presence of endometrial glands and stroma outside the uterine lining. While prevalence estimates vary depending on the population studied, endometriosis is thought to affect approximately one in ten reproductive aged women, up to 50% of women with infertility, and up to 70% of adolescents with chronic pelvic pain. Over 10 million women in the United States have endometriosis and incur significantly higher direct and indirect healthcare costs than those without. Annual health care costs are estimated at $100 billion in the United States alone. While the majority of patients report the onset of endometriosis symptoms during adolescence, delays in diagnosis are common and range from 7 to 12 years. During these delays, women may suffer from debilitating symptoms interfering with school and social activities, and commonly experience reduced health-related quality of life and work productivity. When left untreated, endometriosis can progress significantly in over 50% of patients and result in a higher stage of disease. Therefore, timely intervention and maintenance of therapy is critical for preventing the progression of disease and patient burden. Therapeutic options for endometriosis include surgical and medical management. Because surgery is not curative, long-term medical therapy is often advised to prevent recurrence of symptoms and retard the progression of disease. Nonsteroidal anti-inflammatory drugs (NSAIDs) are commonly used for endometriosis-related pain but do not remove or decrease deposits of ectopic endometrium. Hormonal therapies are the mainstay of medical therapy as they can inhibit prostaglandin production that contributes to pain, and cause decidualization and atrophy of ectopic endometrial tissue. Unfortunately, hormonal treatments have varied degrees of success and no data support one treatment over another. Additionally, the treatment choice may be limited to medication side effects, availability, costs, and contraceptive needs. Hormonal treatments do not cure endometriosis; 11-19% of women may not experience any relief with medical therapy, and up to a third of women experience recurrence of pain symptoms after treatment cessation. Additionally, as endometriosis is predominantly a disease of young reproductive-aged women, patients may desire a treatment with a different mechanism of action that does not impact ovarian function and fertility. There remains an unmet clinical need among women with endometriosis for effective and well-tolerated medical therapies. Metformin, an insulin-sensitizing oral biguanide, is approved for the treatment of type 2 diabetes. Several published studies using in vitro and animal models have implicated metformin with a regression of endometriotic implants and reduction of inflammatory activity. Yet, the mechanisms of action of metformin remain to be further elucidated. Only one prospective study to date has investigated the use of metformin in humans as monotherapy for endometriosis; this study had substantial limitations. Further investigation will be improved with participant and provider blinding, use of validated pain measures, and inclusion of a broader population of patients affected by endometriosis. A randomized clinical trial is necessary to investigate the mechanisms and efficacy of metformin as an anti-endometriotic drug.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
TRIPLE
Enrollment
14
Metformin dosage titrated from 500 mg/daily for 2 weeks, then 1000 mg/daily for 2 weeks, 1500 mg/daily for 2 weeks, and then achieving 2000 mg/daily for a duration of 6 months of treatment.
1 tablet orally with evening meal for 2 weeks, then 1 tablet twice daily for 2 weeks, then 3 tablets split twice daily for 2 weeks, then 4 tablets split twice daily, for a total of 6 months of treatment.
Boston Children's Hospital
Boston, Massachusetts, United States
Change in pain assessed by the Brief Pain Inventory Interference Scale (BPI) over 6 months
The BPI Interference Scale is a 7-item composite pain measurement. This self-report measure assesses the extent to which pain interferes with various components of physical and emotional functioning and sleep. The items in this scale can be grouped into those that assess physical functioning (general activity; walking ability; normal work, including both work outside the home and housework), those that assess emotional functioning (mood; relations with people; enjoyment of life), and a single item that assess the extent to which pain interferes with sleep. The arithmetic mean of the seven interference items can be used as a measure of pain interference. The BPI is anchored between a scale of zero (no pain/interference) to ten (maximum pain/interference). The magnitude of treatment-associated change in BPI Interference Scale scores in open-label and randomized clinical trials ranges from 1 to 3 points, depending on the specific pain conditions and treatments studied.
Time frame: once at each of the three visits (at baseline, 3 months, 6 months)
Change in pain severity measured by Visual Analog Scale (VAS) over 6 months
VAS: A measurement of pain intensity, assessed by a 0 to 10 numerical rating scale, to rate maximum and average pain intensity over the preceding 7 days. Higher scores indicate more severe pain intensity.
Time frame: once at each of the three visits (at baseline, 3 months, 6 months)
Change in emotional functioning assessed by Beck Depression Inventory-II (BDI) over 6 months
The BDI is a 21-item self-report instrument that provides a rapid assessment of depressive symptoms. BDI has been used in many studies of chronic pain, including chronic pelvic pain and endometriosis. Total scores on the BDI range from 0 to 63. The BDI takes about 5-10 minutes to complete. Scores below 13 should be considered to reflect "minimal or no" depression, with score ranges of 14 to 19, 20 to 28, and 29 to 63 reflect "mild to moderate," "moderate to severe," and "severe" depression, respectively.
Time frame: once at each of the three visits (at baseline, 3 months, 6 months)
Change in ratings of overall improvement assessed by the Patient Global Impression of Change scale (PGIC)
The PGIC is a seven-point single-item scale with options ranging from 'very much worse' to 'very much improved'. There has been widespread use of the PGIC in recent endometriosis clinical trials, as it readily interprets a person's evaluation of the importance of their improvement or worsening.
Time frame: once at each of the three visits (at baseline, 3 months, 6 months)
Change in quality of life, measured via Endometriosis Health Profile-30 (EHP-30)
The EHP-30 is a reliable instrument and recommended by the American Society for Reproductive Medicine and the European Society for Human Reproduction and Embryology. The questionnaire includes 30 questions in five subcategories, with each category addressing specific problem areas of pain, control and powerlessness, emotional wellbeing, social support, and self-image.
Time frame: once at each of the three visits (at baseline, 3 months, 6 months)
Changes in sexual satisfaction for participants who are sexually active measured by the New Sexual Satisfaction Scale
The NSSS is a 20-item measure assessing sexual sensations, sexual presence/awareness, sexual exchange, emotional connection/closeness, and sexual activity. The full scale takes 5 minutes to complete.
Time frame: once at each of the three visits (at baseline, 3 months, 6 months)
Complete health and medication history assessed by the World Endometriosis Research Foundation (WERF) questionnaire
Study participants will complete an expanded version of the WERF questionnaire for a complete health and medication history
Time frame: once at each of the three visits (at baseline, 3 months, 6 months)
Changes in serum angiogenic/inflammatory markers
Serum samples will also be obtained for measures of inflammation, to test the hypothesis that endometriosis-relevant inflammatory markers will decrease over time in patients treated with metformin compared to those receiving placebo. These markers will include IL-6, IL-8, and VEGF based on the results of prior studies in which metformin appeared to reduce these levels in humans with endometriosis and from endometriotic implants in rats. C-reactive protein (CRP) will also be assessed; CRP has been shown to be upregulated, especially when examined with a high sensitivity assay making it possible to detect subclinical inflammation in women with endometriosis.
Time frame: once at each of the three visits (at baseline, 3 months, 6 months)
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