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Biguanide

Metformin for Breast Cancer Prevention

Phase 3

Waitlist Available

Research Sponsored by Alliance for Clinical Trials in Oncology

Eligibility Criteria Checklist

Specific guidelines that determine who can or cannot participate in a clinical trial

Must have

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

Women eligible to take tamoxifen must be offered tamoxifen prevention as part of their clinical care and have refused tamoxifen treatment

Must not have

Receiving Warfarin

Currently receiving tamoxifen or raloxifene

Timeline

Screening 3 weeks

Treatment Varies

Follow Up up to 5 years

Awards & highlights

Pivotal Trial

Summary

This trial compares metformin to placebo to see if it can prevent breast cancer.

Who is the study for?

This trial is for women at high risk for breast cancer due to factors like a history of certain breast conditions, a strong family history of breast or ovarian cancer, or known BRCA1/2 mutations. Participants must have normal blood counts and organ function, not be pregnant or breastfeeding, and willing to use birth control if menstruating. They should not have had metformin recently, no other active cancers (with some exceptions), and cannot be on specific medications like Warfarin.

What is being tested?

The study is testing whether metformin hydrochloride can prevent the development of breast cancer in patients with atypical hyperplasia or in situ breast cancer compared to a placebo. It's a phase III trial where participants are randomly assigned to either the drug group or the placebo group.

What are the potential side effects?

Potential side effects from metformin may include digestive issues such as nausea and diarrhea, potential vitamin B12 deficiency with long-term use, and rarely lactic acidosis—a serious metabolic complication.

Eligibility Criteria

Inclusion Criteria

You may be eligible if you check “Yes” for the criteria below

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I carry a BRCA1 or BRCA2 mutation and have discussed my options with a genetic counselor.

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I am eligible for tamoxifen but have chosen not to take it.

Exclusion Criteria

You may be eligible for the trial if you check “No” for criteria below:

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I am currently taking Warfarin.

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I am currently taking tamoxifen or raloxifene.

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I have had breast reconstruction with implants or my own tissue.

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I am allergic to metformin.

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I have had radiation therapy on both breasts.

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I am currently taking pyrimethamine, cimetidine, rifampin, or cephalexin.

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My hemoglobin A1c is above 6.3 or I am being treated for diabetes.

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I do not have any severe illnesses or social situations that would stop me from following the study's requirements.

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I have had a biopsy showing invasive cancer.

Timeline

Screening ~ 3 weeks3 visits

Treatment ~ Varies

Follow Up ~ up to 5 years

Screening ~ 3 weeks

Treatment ~ Varies

Follow Up ~up to 5 years

This trial's timeline: 3 weeks for screening, Varies for treatment, and up to 5 years for reporting.

Treatment Details

Side effects data

From 2023 Phase 3 trial • 3649 Patients • NCT01101438

45%

Diarrhea

45%

Fatigue

39%

Hot flashes

31%

Nausea

27%

Peripheral sensory neuropathy

23%

Insomnia

21%

Arthralgia

18%

Pain in extremity

17%

Headache

16%

Constipation

14%

Pain

14%

Anxiety

13%

Depression

12%

Back pain

12%

Myalgia

11%

Abdominal pain

11%

Hypertension

11%

Alopecia

10%

Anorexia

10%

Dyspepsia

10%

Bloating

Weight loss

Flatulence

Lymphedema

Cough

Dyspnea

Vomiting

Edema limbs

Dizziness

Gastroesophageal reflux disease

Dermatitis radiation

Breast pain

Weight gain

Arthritis

Bone pain

Dysgeusia

Vaginal dryness

Hyperglycemia

100%

80%

60%

40%

20%

Study treatment Arm

Metformin

Placebo

Awards & Highlights

Pivotal Trial

The final step before approval, pivotal trials feature drugs that have already shown basic safety & efficacy.

Trial Design

2Treatment groups

Experimental Treatment

Placebo Group

Group I: Arm I: metformin hydrochlorideExperimental Treatment1 Intervention

Patients receive metformin hydrochloride PO QD or BID for 24 months. Patients will continue metformin 850 mg PO BID for months 13-24. Patients will undergo RPFNA at 24 months. Follow up visits will be performed at 36 and 48 months after the start of treatment.

Group II: Arm II: placeboPlacebo Group1 Intervention

Patients receive placebo PO QD or BID for 12 months. Patients may crossover to Arm I for months 13-24.

Treatment

First Studied

Drug Approval Stage

How many patients have taken this drug

metformin hydrochloride

2010

Completed Phase 3

~5940

0 / 11Eligibility criteria met