The purpose of this study is to assess the safety and efficacy of oral abiraterone acetate plus oral prednisone and oral abiraterone acetate plus oral prednisone plus oral exemestane, each compared with oral exemestane alone, in postmenopausal women with estrogen receptor-positive (ER+) metastatic (spreading) breast cancer that has relapsed after treatment with letrozole or anastrozole.
This is a randomized (study drug assigned by chance), open-label (all participants will know the identity of the assigned study drug) study divided into three phases, screening, treatment, and follow-up. During screening, potential patients will be assessed for study eligibility after providing signed informed consent. The treatment phase will comprise a series of 28-day cycles with continuous study treatment until breast cancer progression, when an end-of-treatment visit will be completed before the follow-up phase begins. The duration of participation in the study for an individual patient may be up to approximately 7 years, including follow-up evaluations. Patients will be evaluated for the safety and effectiveness of study treatments. During the treatment phase, patients will take the following study drugs by mouth once daily: abiraterone acetate, 1 g/day, as four 250-mg tablets, on an empty stomach, and patients must not eat for at least 1 hour after abiraterone acetate; prednisone (prednisolone when prednisone is not available), 5 mg/day; and exemestane, 25 mg/day, as a single tablet. The treatment phase will consist of a series of 28-day cycles with continuous study treatment until breast cancer progression. At the planned interim analysis, the Data Review Committee has recommended that further randomization to the abiraterone acetate alone group be stopped and that the study is to be continued otherwise.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
NONE
Enrollment
297
Abiraterone acetate, type=equal, unit=mg, number=250, form=tablet, route=oral use, 4 tablets
Prednisone or Prednisolone, type=equal, unit=mg, number=5, form=tablet, route=oral use. All drugs are taken once daily.
Abiraterone acetate, type=equal, unit=mg, number=250, form=tablet, route=oral use, 4 tablets
Unnamed facility
Muscle Shoals, Alabama, United States
Unnamed facility
Fresno, California, United States
Unnamed facility
Los Angeles, California, United States
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Monterey, California, United States
Unnamed facility
Chicago, Illinois, United States
Unnamed facility
Progression-Free Survival (PFS)
Progression-free survival was defined as the time from randomization to first occurrence of disease progression (either radiographic or clinical), or death from any cause. PFS was determined using radiographic progression defined by Response Evaluation Criteria in Solid Tumors (RECIST) on measurable lesions captured by computed tomography (CT) or magnetic resonance imaging (MRI). Clinical disease progression was considered only when disease progression could not be confirmed by CT or MRI, such as when the disease site is skin, bone marrow, or central nervous system.
Time frame: Approximately 2 years
Overall Survival (OS)
OS was calculated as the time from randomization to death from any cause.
Time frame: Approximately 3 years
Overall Response Rate (ORR)
Overall response rate was defined as the percentage of participants with measurable disease achieving a best overall response of either complete response (CR) or partial response (PR) based on RECIST. CR: disappearance of all target lesions and non-target lesions. PR: at least a 30 percent (%) decrease in the sum of longest diameter (LD) of target lesions or persistence of one or more non-target lesion(s) or/and maintenance of tumor marker level above the normal limits.
Time frame: Approximately 2 years
Clinical Benefit Rate
Clinical benefit rate was defined as the percentage of participants with measurable disease achieving a best overall response of a CR, PR, or stable disease (SD) for at least 6 months based on RECIST. Stable disease: neither sufficient shrinkage to qualify for PR nor sufficient increase to qualify for progressive disease (PD), taking as reference the smallest sum diameters while on study and persistence of one or more non-target lesion(s) and/or maintenance of tumour marker level above the normal limits.
Time frame: Approximately 2 years
Duration of Response
Duration of objective response was measured from the first time that the CR or PR was achieved to the first observation of disease progression (either radiographic or clinical) based on the RECIST criteria.
Time frame: Approximately 2 years
Change From Baseline in Serum Endocrine Biomarkers (Estradiol and Estrone) at End of Treatment
Change from baseline in serum endocrine biomarkers (estradiol and estrone) was summarized by treatment at end of treatment.
Time frame: Baseline and End of treatment (approximately 2 years)
Change From Baseline in Serum Endocrine Biomarkers (Progesterone and Testosterone) at End of Treatment
Change from baseline in serum endocrine biomarkers (Progesterone and Testosterone) was summarized by treatment at end of treatment.
Time frame: Baseline and End of treatment (approximately 2 years)
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Waterville, Maine, United States
Unnamed facility
Boston, Massachusetts, United States
Unnamed facility
Ann Arbor, Michigan, United States
Unnamed facility
Henderson, Nevada, United States
Unnamed facility
East Syracuse, New York, United States
...and 71 more locations