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RecruitingPhase 3

Metformin for the Treatment of Insulin Resistance in Women With Stage I-III Breast Cancer Completing Chemotherapy

Metformin (Dimethylbiguanide) and Insulin Resistance in Women Completing Neoadjuvant and/or Adjuvant Cytotoxic Treatment of Stage I-III Breast Cancer

Who can join

As published by the study on ClinicalTrials.gov. "Not stated" means the study hasn't said — ask the study team.

Age
18 Years and older
Sex
Female only
Healthy volunteers
Not accepted
Compensation
Not stated

Other requirements are listed under Eligibility below. Only the study team can confirm whether you can join.

What to expect

No one can promise a trial will help you personally — that is what the research is trying to find out.

What participation involves

  • Time periods mentioned: 12 months
  • Procedures mentioned: Blood draws

Only what the study's summary and detailed description on ClinicalTrials.gov say. Time periods may describe the whole study or a part of it — ask the study team what applies to you.

Show the study's own words
  • "ARM I: Patients receive standard of care healthy diet and exercise handouts and extended release metformin orally (PO) once daily (QD) for 12 months in the absence of disease progression or unacceptable toxicity."
  • "Additionally, patients undergo blood sample collection throughout the study."
Compensation
Not stated
  • Study-related exams and procedures are typically provided at no cost. This is how many trials work in general — confirm the details for this study with the study team.
  • Participants are monitored closely by the research team throughout the study.
  • Some participants may receive access to an investigational treatment, which is still being studied.
  • Your participation helps researchers learn whether this approach could help future patients.

About this study

In plain language

This study tests whether adding metformin to usual care helps prevent or reverse insulin resistance, when the body does not respond well to insulin. It also tracks how often women develop insulin resistance and type 2 diabetes. It is for women with stage I–III breast cancer who have finished chemotherapy and are now cancer-free.

This phase III trial evaluates how often women develop insulin resistance and type-2 diabetes and compares metformin with usual care to usual care alone in treating insulin resistance in women with stage I-III breast cancer after chemotherapy. Insulin resistance occurs when cells stop responding to insulin and is a risk factor for developing diabetes and heart disease. Higher levels of insulin have been shown to be associated with aggressive breast cancer. Metformin hydrochloride decreases the amount of glucose (a type of sugar) released into the bloodstream from the liver and increases the body's use of the glucose. Metformin as well as standard of care diet and exercise education is known to lower blood sugar. However, chemotherapy may accelerate metabolic disorders, such as high blood sugar, and the impact of metformin in these breast cancer survivors is not known. Giving metformin with usual care may be more effective than usual care alone in preventing or reversing insulin resistance in women with stage I-III breast cancer after chemotherapy.

Compensation is read from the study's own description and may be missing — always confirm with the study team.

Eligibility

Who can join

  • Be at least 18 years old and have been assigned female at birth.
  • Have had invasive stage I–III breast cancer, meaning cancer that grew into nearby breast tissue.
  • Have finished treatment given after surgery within the past 5 years and now be cancer-free.
  • Be able to read and understand English or Spanish for questionnaires.
  • You or your legal representative must give written consent to join.
  • Agree to blood tests, including a draw of less than 2 tablespoons, and medical record reviews over 2 years.
  • Weight-loss drugs, such as semaglutide, started before the cancer diagnosis may be continued during the study.

Who can't join

  • Currently taking metformin, another diabetes medicine by mouth, tamoxifen, or an aromatase inhibitor (a hormone treatment for breast cancer). Weight-loss drugs are allowed.
  • Have a metformin allergy or another reason metformin would be unsafe.
  • Have poor kidney function, including a kidney filtering rate below 60, or a bilirubin level above 2.5 mg/dL. Bilirubin is a waste product measured in blood.
  • Have been diagnosed with type 1 or type 2 diabetes.
  • Are pregnant, or are within 1 year of pregnancy and finishing breastfeeding.
  • Have another active cancer, unless its course or treatment would not affect study safety or results.
  • Have another condition that makes joining unsafe, or may not be able to follow all study steps, as judged by the study doctor.
  • Are a study team member or an employee supervised directly or indirectly by the lead study doctor, another study doctor, or the study manager.

Simplified for readability. The official criteria below are what the study team uses.

Official eligibility criteria

Inclusion Criteria: * Documented informed consent of the participant and/or legally authorized representative * Agreement to allow lab draw of approximately 26 mL of blood (less than 2 tablespoons) * To check blood counts, organ function and disease at baseline and 12 months * Review of clinical charts at pre-registration\* (refer to Study Calendar), baseline, 3 months, 6 months,12 months, and 24 months * Research labs at baseline, 6 months,12 months, and 24 months * Age: ≥ 18 years * Female sex assigned at birth * Ability to read and understand English or Spanish for questionnaires * Diagnosis of invasive breast cancer stages I-III * Completed adjuvant treatment for Stage 1-3 breast cancer within 5 years and are disease free. * Women who receive drugs for weight loss - e.g. semaglutide - prior to diagnosis are eligible for this protocol and can continue the drug during the intervention. Exclusion Criteria: * Currently taking metformin or any other oral antidiabetic medications. Weight loss medications are permitted - e.g. semaglutide * Taking tamoxifen or aromatase inhibitor * Contraindication to metformin prevention such as acute hypersensitivity or allergic reaction to metformin * Participants with acute or chronic renal insufficiency (a glomerular filtration rate \[GFR\] \< 60 mL/min/1.73m\^2) or those with acute renal insufficiency of any severity due to hepato-renal syndrome or in the peri-operative liver transplantation period * Bilirubin of \>2.5 mg/dL (normal range 0.1-1.2 mg/dL). * Previously diagnosed type 1 or type 2 diabetes * Patients pregnant or within 1 year of pregnancy and completion of lactation (to be determined at randomization). * Other active malignancy. Patients with a prior or concurrent malignancy whose natural history or treatment does not have the potential to interfere with the safety or efficacy assessment of the investigational regimen are eligible for this trial * Any other condition that would, in the investigator's judgment, contraindicate the patient's participation in the clinical study due to safety concerns with clinical study procedures * An employee who is under the direct/indirect supervision of the principal investigator (PI)/a co-investigator/the study manager and/or a direct study team member * Prospective participants who, in the opinion of the investigator, may not be able to comply with all study procedures (including compliance issues related to feasibility/logistics)

Study sites (3)

CA