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

Recruiting now · Phase 3

Conditions studied: Anatomic Stage I Breast Cancer AJCC v8, Anatomic Stage II Breast Cancer AJCC v8, Anatomic Stage III Breast Cancer AJCC v8, Invasive Breast Carcinoma

In brief

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.

Key facts

Study ID: NCT06763328
Run by: City of Hope Medical Center
People needed: 80
Starts: 2024-12-16
Expected to finish: 2029-06-16
Last updated by the study team: 2026-06-12

Who can join

Age: 18 and older. Sex: female. Healthy volunteers: not accepted.

You may qualify if…

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.

You may not qualify if…

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)

Where it is running

City of Hope Medical Center — Duarte, California, United States (enrolling)
UC San Diego Moores Cancer Center — La Jolla, California, United States
University of California-Riverside — Riverside, California, United States

Full record on ClinicalTrials.gov

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