A Phase III Randomized Trial of Metformin vs Placebo in Early Stage Breast Cancer
Condition: Breast Cancer
MeSH terms: Breast Neoplasms
Intervention: metformin hydrochloride; placebo
Intervention description: Given orally; Given orally
Intervention MeSH terms: Metformin
Phase: Phase 3
Study type: Interventional
Primary purpose: Treatment
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Triple (Participant, Investigator, Outcomes Assessor)
Enrollment: 3649.0
Sex: All
Minimum age: 18 Years
Maximum age: 74 Years
Healthy volunteers: No
Keywords: stage I breast cancer; stage II breast cancer; stage IIIA breast cancer; stage IIIC breast cancer; male breast cancer; HER2-negative breast cancer; estrogen receptor-positive breast cancer; HER2-positive breast cancer; progesterone receptor-positive breast cancer

Summary:

      This study is looking at whether Metformin, an agent that is commonly used to treat diabetes,
      can decrease or affect the ability of breast cancer cells to grow and whether Metformin will
      work with other therapies to keep cancer from recurring. Health Canada has not approved the
      sale or use of Metformin to treat breast cancer, although they have approved its use in this
      clinical trial. Although Metformin is approved by the FDA for the treatment of diabetes, its
      use in breast cancer is considered investigational.
    

Eligibility criteria:

        Eligibility Criteria:

          -  Subjects must have histologically confirmed invasive breast cancer and be enrolled in
             the trial within 12 months after the first histologic diagnosis of invasive breast
             cancer. A core biopsy interpreted as invasive cancer meets this criterion; otherwise,
             the date of first histologic diagnosis will be the date of first surgical procedure
             that identifies invasive cancer (biopsy, lumpectomy or mastectomy). Neoadjuvant
             subjects should have no evidence of clinical T4 disease prior to chemotherapy and
             surgery. Bilateral breast carcinoma is allowed provided diagnoses are synchronous -
             that is, within 3 months of one another - and at least one of the two breast
             carcinomas meet the eligibility criteria and neither violates the eligibility
             criteria.

          -  All subjects (both adjuvant and neo-adjuvant) must have sentinel lymph node biopsy
             and/or axillary lymph node dissection.

        Sentinel lymph node biopsy alone is allowed in the following instances:

          1. sentinel lymph node biopsy is negative: pN0

          2. sentinel lymph node biopsy is positive for isolated tumour cells only: pN0 (i+)

          3. * clinically node negative, T1-2 tumours with sentinel lymph node biopsy positive in ≤
             2 lymph nodes without extra-capsular extension or matted nodes and undergoing breast
             conserving surgery and tangential whole breast irradiation (* excludes subjects
             treated with neo-adjuvant systemic therapy)

        Definitive surgery and/or chemotherapy have been completed at least 4 weeks prior to
        randomization. Surgical margins must be clear of invasive carcinoma. If there is
        microscopic residual ductal in situ disease present at lumpectomy or total mastectomy
        margins, further excision is highly recommended. If further excision is not undertaken, the
        subject may still be entered on study, provided that in addition to breast or chest wall
        irradiation, a boost to the tumour bed is delivered. In situ lobular disease at the margin
        is acceptable.

        Adjuvant subjects with the following pT pN combinations are eligible:

          -  pT1c, pN0 AND negative estrogen and progesterone receptors AND HER2 negative OR

          -  pT2N0 and at least one of the following tumour characteristics: histologic grade 3,
             lymphovascular invasion, negative estrogen and progesterone receptors, HER2 positive,
             Oncotype Dx recurrence score ≥ 25 (or if Oncotype Dx recurrence score is not
             available, Ki67 > 14%) OR

          -  Subjects with pT3, pN0 OR

          -  Subjects with pT1-3, pN1-3

        The eligibility of neo-adjuvant subjects is assessed on the basis of cTNM. The same
        eligible TNM combinations apply.

          -  HER2 status must be known. (Positive = 3+ over-expression by IHC in > 30% of invasive
             tumour cells OR HER2 gene amplification by FISH/CISH > 6 HER2 gene copies per nucleus,
             OR a FISH/CISH ratio: HER2 gene copies to chromosome 17 signals of ≥ 2.2. All other
             results will be considered negative).

          -  Patients must have had a bilateral mammogram within 12 months prior to randomization,
             unless the initial surgery was a total mastectomy, in which case only a mammogram of
             the remaining breast is required. (Subjects with bilateral total mastectomies and no
             mammogram within 12 months prior to randomization must, instead, have a physical
             examination of the chest wall to ensure there is no residual or recurrent disease at
             the time of randomization. The date of this examination is used in place of the
             mammogram date on the eligibility checklist.)

          -  Investigations, including chest X-ray or CT chest, bone scan (with radiographs of
             suspicious areas) and abdominal ultrasound or liver scan or CT abdomen have been
             performed between the first histologic diagnosis and the time of randomization.

               -  Chest X-Ray, 2 view (or Chest CT) is mandatory

               -  Bone scans (with x-rays of abnormal areas) are required only if there are signs
                  or symptoms of metastatic disease

               -  Abdominal imaging is required only if there are signs or symptoms of metastatic
                  disease

          -  Hematology investigations (WBC, Granulocytes, Platelets, Hemoglobin) have been
             completed within 28 days prior to randomization and results are available.

          -  Biochemistry investigations have been completed within 28 days prior to randomization
             and values are within the parameters required by the protocol.

        AST < 1.8 X ULN; ALT < 1.8 X ULN; Alkaline Phosphatase < 2 X ULN; Serum Creatinine < 115
        μmol/L (1.3mg/dL) Serum Bilirubin < institution ULN (except for subjects with Gilbert's
        Disease who are eligible despite elevated serum bilirubin level)

          -  ECOG Performance Status of 0,1 or 2 (at baseline evaluation visit within 28 days prior
             to randomization).

          -  Age ≥ 18 and < 75 and life expectancy of at least 5 years (18 years of age was used as
             a cut-off due to the lack of data indicating that breast cancer is a health issue in
             the < 18 years age group and metformin safety in pediatric patients has not been
             confirmed. Age > 80 carries increased risk of lactic acidosis and study intervention
             is for 5 years).

          -  Subjects must be accessible for treatment and follow-up. Investigators must assure
             themselves the subjects randomized on this trial will be available for complete
             documentation of the treatment, adverse events, and follow-up.

          -  In accordance with NCIC CTG policy, protocol treatment is to begin within 10 working
             days of patient randomization.

          -  Subject consent must be obtained according to local Institutional and/or University
             Human Experimentation Committee requirements. It will be the responsibility of the
             local participating investigators to obtain the necessary local clearance, and to
             indicate in writing to the NCIC CTG Study Coordinator that such clearance has been
             obtained, before the trial can commence in that centre. Because of differing
             requirements, a standard consent form for the trial will not be provided but a sample
             form is given. A copy of the initial full board REB approval and approved consent form
             must be sent to the central office. The patient must sign the consent form prior to
             randomization or registration. Please note that the consent form for this study must
             contain a statement which gives permission for the NCIC CTG and monitoring agencies to
             review patient records (see Section 16 for further details).

        For the first 888 eligible English or French-speaking subjects only (sub-set enrollment
        completed 2011NOV04):

          -  Subject is able (i.e. sufficiently fluent) and willing to complete the Quality of Life
             (EORTC QLQ C-30 and Trial Specific Checklist) in English or French. The baseline
             assessment must already have been completed at the time of enrollment. Inability
             (illiteracy in English or French, loss of sight or other equivalent reason) to
             complete questionnaires will not make the patient ineligible for the study; however,
             ability but unwillingness to complete the questionnaires will make the patient
             ineligible. (Once the target number of 888 subjects is achieved, this criterion will
             no longer need to be fulfilled.) [See Appendix VI]. Sub-set enrollment completed
             2011NOV04.

          -  English-speaking subjects who have completed the Quality of Life Questionnaire who are
             able (i.e. sufficiently fluent) and willing to complete Nurses Health Study II
             Physical Activity Questionnaire and Block Alive Screener in English. The baseline
             assessment must already have been completed at the time of enrollment. Inability
             (illiteracy in English, loss of sight or other equivalent reason) to complete
             questionnaires will not make the patient ineligible for the study; however, ability
             but unwillingness to complete the questionnaires will make the patient ineligible.
             (This component of the study will close at the same time as the Quality Of Life
             sub-study.) Closed to new patient enrollment as of 2011NOV04.

        Ineligibility Criteria:

          -  Subjects with a history of other malignancies, except: adequately treated non-melanoma
             skin cancer, curatively treated in-situ cancer of the cervix, or other solid tumours
             curatively treated with no evidence of disease for ≥ 5 years.

          -  Subjects with locally recurrent or metastatic breast carcinoma. (Subjects with prior
             invasive breast cancer at any time are not eligible. Subjects with prior DCIS only in
             either breast are eligible provided the DCIS has been curatively treated including
             surgery, radiotherapy and/or Tamoxifen).

          -  Subjects whose axillary node status is unknown.

          -  Known diabetes (type 1 or 2) or baseline fasting glucose > 7.0 mmol/L (126 mg/dL).
             (Sampled and assayed according to local institution's procedures.)

          -  Known hypersensitivity or intolerance to metformin.

          -  Any condition associated with increased risk of metformin-associated lactic acidosis
             (e.g. congestive heart failure defined as New York Heart Association {NYHA} Class III
             or IV functional status [see Appendix IX], history of acidosis of any type; habitual *
             Currently taking metformin, sulfonylureas, thiazolidinediones or insulin for any
             reason.

          -  Current or planned pregnancy or lactation in women of child-bearing potential. Men
             should not father a child. (An effective method of birth control should be used while
             on study treatment which could include abstinence, IUD, condoms or other barrier
             methods of birth control because the safety of metformin in pregnancy or in male
             fertility has not been established).

          -  Concurrent or planned participation in randomized trials of weight loss or exercise
             interventions or trials targeting insulin, IGF-1 or their receptors, or involving P13K
             inhibitors (at the time of randomization)*.

          -  These interventions would interfere with the primary endpoint. (Also, in general,
             double randomizations in breast cancer trials for MA.32 patients are permitted only if
             the patient meets all the eligibility criteria for MA.32 and the sponsor of the
             previous trial has no objection to the patient also being enrolled in MA.32).