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Exemestane in Treating Postmenopausal Women With Resected Stage I, Stage II, or Stage IIIA Breast Cancer Who Have Completed 5 Years of Tamoxifen

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details.
ClinicalTrials.gov Identifier: NCT00016432
Recruitment Status : Completed
First Posted : January 27, 2003
Last Update Posted : April 19, 2011
National Cancer Institute (NCI)
Information provided by:
NSABP Foundation Inc

Brief Summary:

RATIONALE: Estrogen can stimulate the growth of breast cancer cells. Hormone therapy using exemestane may fight breast cancer by reducing the production of estrogen by the tumor cells. It is not yet known whether exemestane is effective in preventing the recurrence of breast cancer.

PURPOSE: Randomized phase III trial to study the effectiveness of exemestane in preventing cancer recurrence in postmenopausal women who have resected stage I, stage II, or stage IIIA breast cancer and have completed 5 years of tamoxifen.

Condition or disease Intervention/treatment Phase
Breast Cancer Drug: exemestane Drug: Placebo Phase 3

Detailed Description:


  • Determine whether the administration of 5 years of exemestane after 5 years of tamoxifen therapy is more effective than 5 years of prior tamoxifen therapy alone in prolonging disease-free survival, overall survival, and time to treatment failure in postmenopausal women with resected stage I, II, or IIIA breast cancer.
  • Determine the effect of tamoxifen withdrawal on bone, in terms of height, fractures, and total alkaline phosphatase in these patients and on bone mineral density and bone biochemical markers in a subset of patients.
  • Determine the effect of exemestane on bone loss after tamoxifen withdrawal in these patients.
  • Evaluate the quality of life of a subset of these patients.

OUTLINE: This is a randomized study. Patients are randomized to 1 of 2 treatment arms.

  • Arm I: Patients receive oral exemestane daily for 5 years.
  • Arm II (closed as of 10/15/03): Patients receive an oral placebo daily for 5 years.

Quality of life is assessed at baseline and then every 6 months for 5.5 years.

Patients are followed every 6 months for 6 years and then annually thereafter.

PROJECTED ACCRUAL: A total of 3,000 patients will be accrued for this study within 3 years and 4 months.

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Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 1598 participants
Allocation: Randomized
Intervention Model: Single Group Assignment
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Primary Purpose: Treatment
Official Title: A Randomized Trial Evaluating The Effect Of Exemestane In Clinical Stage T1-3 N0-1 M0 Postmenopausal Breast Cancer Patients Completing At Least Five Years Of Tamoxifen Therapy
Study Start Date : May 2001
Actual Primary Completion Date : October 2003
Actual Study Completion Date : February 2011

Resource links provided by the National Library of Medicine

MedlinePlus related topics: Breast Cancer
Drug Information available for: Exemestane

Arm Intervention/treatment
Experimental: Group 1
Drug: exemestane
25 mg for 5 years

Placebo Comparator: Group 2
Drug: Placebo

Primary Outcome Measures :
  1. Disease-free survival [ Time Frame: Every 12 months until breast cancer recurrence, second primary cancer or death from any cause. ]

Secondary Outcome Measures :
  1. Overall survival [ Time Frame: Death from any cause ]
  2. Time to treatment failure [ Time Frame: time from randomization to recurrence or contralateral second primary cancer ]
  3. Bone measure as measured by total alkaline phosphatase, fracture history, and height measurement [ Time Frame: measurements taken at regular intervals from randomization through 6 years following randomiztion ]

Information from the National Library of Medicine

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Ages Eligible for Study:   18 Years and older   (Adult, Older Adult)
Sexes Eligible for Study:   Female
Accepts Healthy Volunteers:   No


  • Histologically confirmed invasive adenocarcinoma of the breast at time of original diagnosis

    • Tumor confined to the breast and ipsilateral axilla on clinical exam (T1-3, N0-1, M0) (stage I-IIIA)
    • No ipsilateral lymph nodes clinically fixed to one another or to other structures (N2 disease) at time of original diagnosis
  • Prior surgical resection, including 1 of the following:

    • Total mastectomy and axillary dissection (modified radical mastectomy) OR
    • Lumpectomy and axillary dissection

      • Prior post-lumpectomy breast radiotherapy required
    • Prior sentinel node biopsy allowed with the exception of the following:

      • If any sentinel node is histologically positive by hematoxylin and eosin (H & E) OR histologically suspicious on H & E and confirmed positive by immunohistochemistry then the patient must have a complete axillary dissection
    • Previously resected margins must be clear of invasive tumor and ductal carcinoma in situ
  • Currently disease free
  • Previously treated with tamoxifen for 57-66 months

    • Completed tamoxifen within the past 180 days
  • No bilateral malignancy or mass in the opposite breast suspicious for malignancy unless biopsy proven negative
  • No local, regional, or distant recurrence of disease or second primary breast malignancy (including contralateral breast cancer)
  • No advanced disease at time of original diagnosis (e.g., ulceration, erythema, infiltration of the skin or underlying chest wall [complete fixation], peau d'orange, or skin edema of any magnitude)

    • Tethering or dimpling of the skin or nipple inversion allowed
  • Current skeletal pain allowed if a bone scan and/or radiologic exam is negative for metastatic disease
  • Hormone receptor status:

    • Primary tumor estrogen receptor (ER) positive AND/OR
    • Progesterone receptor positive
    • Borderline ER positive tumors allowed if previously treated with tamoxifen



  • Postmenopausal


  • Female

Menopausal status:

  • Postmenopausal, defined as 1 of the following:

    • Prior bilateral oophorectomy
    • Absence of spontaneous menstrual cycle for more than 1 year
    • Follicle-stimulating hormone within the postmenopausal range if under 55 and had a prior hysterectomy without a bilateral oophorectomy

Performance status:

  • Not specified

Life expectancy:

  • At least 10 years


  • Absolute granulocyte count at least 1,500/mm^3
  • Platelet count at least 100,000/mm^3
  • Hemoglobin normal


  • Bilirubin less than 2 times upper limit of normal (ULN)
  • SGOT or SGPT no greater than 2.5 times ULN
  • Alkaline phosphatase less than 2 times ULN
  • No systemic hepatic disease that would preclude study participation


  • Creatinine no greater than 1.5 times ULN
  • No systemic renal disease that would preclude study participation


  • No systemic cardiovascular disease that would preclude study participation


  • No other malignancy within the past 5 years except effectively treated squamous cell or basal cell skin cancer, surgically treated carcinoma in situ of the cervix, or surgically treated lobular carcinoma in situ of the ipsilateral or contralateral breast
  • No nonmalignant systemic disease that would preclude study participation
  • No psychiatric or addictive disorder that would preclude informed consent
  • Not pregnant


Biologic therapy:

  • Not specified


  • Prior adjuvant chemotherapy allowed if administered concurrently with or prior to tamoxifen

Endocrine therapy:

  • See Disease Characteristics
  • No concurrent estrogen, progesterone, clomiphene, testosterone, gonadotropin-releasing hormone, oral contraceptives, selective estrogen-receptor modulators, or dehydroepiandrosterone (DHEA)

    • Estring or estrogen vaginal cream at 0.3 mg or 1/8 of an applicator applied vaginally 3 times a week allowed
  • No other concurrent systemic hormonal therapy (e.g., tamoxifen or raloxifene)


  • See Disease Characteristics
  • Prior post-mastectomy loco-regional radiotherapy or post-lumpectomy regional radiotherapy allowed


  • See Disease Characteristics


  • Prior participation in other adjuvant NSABP study allowed if study was reported in peer-review publication or tamoxifen was not a study drug
  • Concurrent bisphosphonates or calcitonin for prevention or treatment of osteoporosis allowed
  • Concurrent statins (simvastatin, pravastatin, fluvastatin, atorvastatin, or lovastatin) or other drugs to control lipid levels allowed

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT00016432

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Sponsors and Collaborators
NSABP Foundation Inc
National Cancer Institute (NCI)
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Principal Investigator: Norman Wolmark, MD NSABP Foundation Inc
Publications of Results:
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Responsible Party: Norman Wolmark, MD, NSABP Foundation, Inc.
ClinicalTrials.gov Identifier: NCT00016432    
Other Study ID Numbers: NSABP B-33
First Posted: January 27, 2003    Key Record Dates
Last Update Posted: April 19, 2011
Last Verified: April 2011
Keywords provided by NSABP Foundation Inc:
stage I breast cancer
stage II breast cancer
stage IIIA breast cancer
Additional relevant MeSH terms:
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Breast Neoplasms
Neoplasms by Site
Breast Diseases
Skin Diseases
Antineoplastic Agents
Aromatase Inhibitors
Steroid Synthesis Inhibitors
Enzyme Inhibitors
Molecular Mechanisms of Pharmacological Action
Estrogen Antagonists
Hormone Antagonists
Hormones, Hormone Substitutes, and Hormone Antagonists
Physiological Effects of Drugs