Could a common diabetes drug stop breast cancer before it starts?

NCT ID NCT01905046

Prevention Sponsor: Alliance for Clinical Trials in Oncology Source: ClinicalTrials.gov ↗

First seen Jun 25, 2026 · Last updated Jun 27, 2026 · Updated 1 time

Summary

This phase 3 trial tests whether taking metformin for 12 months can reduce abnormal cells in the breast tissue of women at high risk for breast cancer. Participants have conditions like atypical hyperplasia or a strong family history. Researchers compare metformin to a placebo to see if it lowers the chance of developing breast cancer.

What this could mean

Our plain-language read of the trial. This is informational only, not medical advice or a prediction.

Active substance: metformin (a common diabetes drug)
What this could lead to: If it works, this could show that a safe, inexpensive drug like metformin helps prevent breast cancer in women at high risk.
What could go wrong: This is a small, early-phase trial with only 86 participants, so results may not apply to everyone. Metformin can cause side effects like stomach upset, and it may not reduce cancer risk.

This is an AI summary of the original study and may miss details. Read our disclaimer.

Study facts

What this study's own registry entry says, in plain language.

Phase

Phase 3

Large-scale testing in a bigger group. Usually the last step before a treatment can be approved.

Participants

86 people

The number who actually took part.

Started

Nov 2015

Expected to finish

Nov 2026

An estimate. End dates often move.

Lead sponsor

Other sponsor

The registry's catch-all category, for sponsors it does not file as a company, a government agency, or a research network.

Who can take part

This study's own entry requirements. Only the study team can say for certain whether you qualify.

Ages

25 to 55 years

Sex

Female participants only

Healthy volunteers

Not accepted

This study is not open to healthy volunteers. The entry requirements below say who it is open to.

Show the full entry requirements

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

* PRE-REGISTRATION-INCLUSION CRITERIA * Must be at increased risk for breast cancer, defined as at least one of the following four criteria: * Having had a prior biopsy demonstrating atypical hyperplasia, lobular carcinoma in situ (LCIS), or ductal carcinoma in situ (DCIS) * A Gail Model Risk of \>= 1.66% over 5 years * A strong family history of breast and/or ovarian cancer which is defined as at least one of the following: * One first-degree relative with breast cancer before the age of 50 years * One first degree relative with bilateral breast cancer * Two or more first-degree relatives with breast cancer * One first degree relative and two or more second or third degree relatives with breast cancer * One first-degree relative with breast cancer and one or more relatives with ovarian cancer * Two second or third degree relatives with either breast cancer and one or more with ovarian cancer * One second or third degree relative with breast cancer and two or more with ovarian cancer * Three or more second or third degree relatives with breast cancer * Known breast cancer (BRCA)1 or BRCA2 mutation carrier providing that the woman has * Met with a genetic counselor to review genetic testing results, and * Has been offered the opportunity to undergo prophylactic mastectomy and oophorectomy * Pre-menopausal women as defined as four menstrual cycles within the last six months prior to pre-registration; women with less than 4 menses within 6 months prior to pre-registration, or women who have had a hysterectomy with ovaries intact will be considered premenopausal if follicle-stimulating hormone (FSH) level is \< 20; women who are using hormonal contraceptives that cause amenorrhea (e.g. injectable and extended oral contraceptives, hormone containing contraceptive ring, or hormone containing intrauterine device) will be considered eligible if they had a minimum of 4 menstrual cycles within the last six months prior to starting on the contraceptive * Digital mammogram within 365 days prior to pre-registration * Mammograms must be read as not suspicious for breast cancer (American College of Rheumatology \[ACR\] class I-III); subjects with a class IV mammogram may be enrolled once they have been evaluated by a breast surgeon and there is no evidence of invasive malignancy * Must be non-pregnant and non-lactating for at least one year prior to pre-registration * If currently menstruating, subjects must use a reliable method of birth control * Willing to provide RPFNA and blood samples for correlative research purposes * REGISTRATION/RANDOMIZATION INCLUSION CRITERIA: * Qualifying cytological atypia in RPFNA, Masood score of 14-17; the qualifying RPFNA (of one or both breasts) must be send to Dr. Seewaldt's laboratory for cytological scoring and proteomic analysis; score results must be received from Dr. Seewaldt's lab prior to patient registration/randomization; test must be done =\< 90 days prior to registration/randomization \* Note: Only the contralateral breast can be aspirated in women with DCIS and those undergoing surgery for an atypical lesion; the decision to aspirate the contralateral breast is at the discretion of the woman's surgeon * Hemoglobin \>= 9 g/dL * Absolute neutrophil count (ANC) \>= 1500/mm\^3 * Platelet count \>= 75,000/mm\^3 * Creatinine =\< 1.4 mg/dL * Total bilirubin =\< 3.0 mg/dL * Aspartate transaminase (AST) =\< 3 x upper limit of normal (ULN) * Alanine transaminase (ALT) =\< 3 x ULN * Negative pregnancy test done =\< 7 days prior to registration/randomization, for women of childbearing potential only \* A female of childbearing potential is a sexually mature female who: 1) has not undergone a hysterectomy or bilateral oophorectomy; or 2) has not been naturally postmenopausal for at least 12 consecutive months (i.e., has had menses at any time in the preceding 12 consecutive months) * Women eligible to take tamoxifen must be offered tamoxifen prevention as part of their clinical care and have refused tamoxifen treatment Exclusion Criteria * Other active malignancy =\< 5 years prior to pre-registration; EXCEPTIONS: non-melanotic skin cancer or carcinoma-in-situ of the cervix; NOTE: if there is a history or prior malignancy, they must not be receiving other specific treatment, i.e., other hormonal therapy, for their cancer * Body mass index (BMI) \< 25 * Receiving Warfarin * Bilateral breast implants or autologous breast flap reconstruction * Active diagnosis of alcoholism * Contraindication to metformin prevention such as acute hypersensitivity or allergic reaction to metformin * Currently receiving tamoxifen or raloxifene * Administration of any investigational agent =\< 30 days prior to pre-registration * Previous radiation to both breasts * Co-morbid systemic illnesses or other severe concurrent disease which, in the judgment of the investigator, would make the patient inappropriate for entry into this study or interfere significantly with the proper assessment of safety and toxicity of the prescribed regimens * Uncontrolled intercurrent illness including, but not limited to, ongoing or active infection, symptomatic congestive heart failure, unstable angina pectoris, cardiac arrhythmia, or psychiatric illness/social situations that would limit compliance with study requirements * Receiving pyrimethamine, cimetidine, rifampin or cephalexin * Women who have a core biopsy or excisional biopsy containing invasive cancer * Women who have taken metformin within the past 90 days * Patients with hemoglobin a1c \> 6.3 or who are being actively treated for diabetes

Get updates

Get notified about this study

Vår säkerhetsrekommendation!

Genom att skicka in godkänner du våra Användarvillkor

Conditions

The condition(s) this trial relates to.

breast carcinoma in situ ductal breast carcinoma in situ lobular breast carcinoma in situ breast cancer prevention target

As listed by the trial registrant

The condition terms exactly as the trial's registrant entered them.

Atypical ductal breast hyperplasia BRCA1 mutation carrier BRCA2 mutation carrier Ductal breast carcinoma in situ Lobular breast carcinoma in situ

Contacts and locations

Locations

City of Hope Comprehensive Cancer Center

Duarte, California, 91010, United States
City of Hope South Pasadena

South Pasadena, California, 91030, United States
Cotton O'Neil Cancer Center / Stormont Vail Health

Topeka, Kansas, 66606, United States
Doctor's Hospital of Laredo

Laredo, Texas, 78041, United States
Duke University Medical Center

Durham, North Carolina, 27710, United States
Greenville Health System Cancer Institute-Andrews

Greenville, South Carolina, 29601, United States
Los Angeles County-USC Medical Center

Los Angeles, California, 90033, United States
M D Anderson Cancer Center

Houston, Texas, 77030, United States
Mayo Clinic in Rochester

Rochester, Minnesota, 55905, United States
Mount Sinai Hospital

New York, New York, 10029, United States
NYP/Columbia University Medical Center/Herbert Irving Comprehensive Cancer Center

New York, New York, 10032, United States
Ohio State University Comprehensive Cancer Center

Columbus, Ohio, 43210, United States
Prisma Health Cancer Institute - Butternut

Greenville, South Carolina, 29605, United States
Prisma Health Cancer Institute - Easley

Easley, South Carolina, 29640, United States
Prisma Health Cancer Institute - Eastside

Greenville, South Carolina, 29615, United States
Prisma Health Cancer Institute - Faris

Greenville, South Carolina, 29605, United States
Prisma Health Cancer Institute - Greer

Greer, South Carolina, 29650, United States
Prisma Health Cancer Institute - Seneca

Seneca, South Carolina, 29672, United States
Prisma Health Cancer Institute - Spartanburg

Boiling Springs, South Carolina, 29316, United States
Prisma Health Greenville Memorial Hospital

Greenville, South Carolina, 29605, United States
Roswell Park Cancer Institute

Buffalo, New York, 14263, United States
The Christ Hospital

Cincinnati, Ohio, 45219, United States
The Community Hospital

Munster, Indiana, 46321, United States
USC / Norris Comprehensive Cancer Center

Los Angeles, California, 90033, United States
University of Kansas Cancer Center

Kansas City, Kansas, 66160, United States
University of Oklahoma Health Sciences Center

Oklahoma City, Oklahoma, 73104, United States
University of Wisconsin Carbone Cancer Center

Madison, Wisconsin, 53792, United States

More trials for these conditions

Other studies related to the condition(s) this trial covers.