A Phase 3 interventional study of Anastrozole and Exemestane in Breast Cancer, sponsored by Institute of Cancer Research, United Kingdom. Completed at 2 sites in United Kingdom. Open to female participants aged 18 Years to 120 Years. Per ClinicalTrials.gov, last updated 2025-06-04.
Sponsored by Institute of Cancer Research, United Kingdom · Phase 3, Interventional, and Treatment
RATIONALE: Estrogen can cause the growth of breast cancer cells. Hormone therapy using fulvestrant, anastrozole, or exemestane may fight breast cancer by blocking the use of estrogen by the tumor cells or by lowering the amount of estrogen the body makes. It is not yet known whether giving fulvestrant together with anastrozole is more effective than giving fulvestrant together with a placebo or exemestane alone in treating breast cancer.
PURPOSE: This randomized phase III trial is studying fulvestrant and anastrozole to see how well they work compared to fulvestrant and a placebo or exemestane alone in treating postmenopausal women with locally advanced or metastatic breast cancer.
OBJECTIVES:
Primary
Secondary
OUTLINE: This is a randomized, partially double-blind and placebo-controlled, multicenter study. Patients are stratified according to the setting in which prior nonsteroidal aromatase-inhibitor therapy was given (adjuvant therapy vs first-line therapy) and participating center. Patients are randomized to 1 of 3 treatment arms.
After completion of study treatment, patients are followed periodically for survival.
PROJECTED ACCRUAL: A total of 750 patients (250 per treatment arm) will be accrued for this study.
12,544 studies on the registry are indexed under Breast Neoplasms; 2,892 are open to participants now.
This study's enrollment of 698 is above the median of 72 across 9,303 interventional studies indexed under Breast Neoplasms.
Browse Breast Neoplasms studies →Institute of Cancer Research, United Kingdom is the lead sponsor of 111 studies on the registry; 27 are open to participants now.
Counted across the registry records on this site, refreshed daily.
DISEASE CHARACTERISTICS:
Histologically or cytologically confirmed adenocarcinoma of the breast
Metastatic disease must be measurable or evaluable
Relapsed or progressed during prior treatment with single-agent nonsteroidal aromatase inhibitor (NSAI)*, meeting either of the following criteria:
Achieved an objective complete response, partial response, or stable disease that lasted ≥ 6 months after prior first-line therapy with NSAI for locally advanced or metastatic disease
Hormone receptor status:
PATIENT CHARACTERISTICS:
Sex
Menopausal status
Postmenopausal, as defined by 1 of the following criteria:
Performance status
Life expectancy
Hematopoietic
Platelet count ≥ 100,000/mm\^3
Hepatic
Renal
Other
PRIOR CONCURRENT THERAPY:
Chemotherapy
Endocrine therapy
Other
Concurrent bisphosphonates for bone metastases allowed provided bisphosphonate therapy has been established for ≥ 6 months
Arimidex/placebo comparator is blinded Faslodex (fulvestrant) IM on day 1,15,29 and monthly thereafter Placebo orally once a day
Drug: Anastrozole · Drug: Fulvestrant
Arimidex/placebo comparator is blinded Faslodex (fulvestrant) IM on day 1,15,29 and monthly thereafter Arimidex (anastrozole) orally once a day
Drug: Anastrozole · Drug: Fulvestrant
exemestane orally once a day
Drug: Exemestane
This may be Anastrazole OR a placebo
Also known as: Arimidex (or placebo)
Also known as: Faslodex
Progression-free Survival
defined as time from randomisation to progression of existing disease, new sites of disease, second primary cancer if change in systemic treatment was necessary, or death from any cause. Progression is defined using Response Evaluation Criteria In Solid Tumors Criteria (RECIST v1.0), as a 20% increase in the sum of the longest diameter of target lesions, or a measurable increase in a non-target lesion, or the appearance of new lesions.
Time frame: Assessed up to 190 months
Objective Response Rate
The proportion of patients identified as having a complete response (CR) or partial response (PR) at any time whilst on study treatment. Response is defined using Response Evaluation Criteria In Solid Tumors Criteria (RECIST v1.0), as either disappearance of all lesions or a \>=30% decrease in the sum of the longest diameter of target lesions with no progressing non-target lesions and no new lesions. Objective Response (OR) = CR + PR
Time frame: From start of treatment, every 3 months to treatment discontinuation and/or up to 190 months
Duration of Response
time from first assessment of response to progression or death. Response is defined using Response Evaluation Criteria In Solid Tumors Criteria (RECIST v1.0), as either disappearance of all lesions or a \>=30% decrease in the sum of the longest diameter of target lesions with no progressing non-target lesions and no new lesions. Progression is defined using Response Evaluation Criteria In Solid Tumors Criteria (RECIST v1.0), as a 20% increase in the sum of the longest diameter of target lesions, or a measurable increase in a non-target lesion, or the appearance of new lesions.
Time frame: Assessed up to 190 months
Clinical Benefit Rate
Complete or partial response or stable disease for at least six months prior to progression. Response is defined using Response Evaluation Criteria In Solid Tumors Criteria (RECIST v1.0), as either disappearance of all lesions or a \>=30% decrease in the sum of the longest diameter of target lesions with no progressing non-target lesions and no new lesions. Stable disease is neither responding or progressing. Progression is defined using Response Evaluation Criteria In Solid Tumors Criteria (RECIST v1.0), as a 20% increase in the sum of the longest diameter of target lesions, or a measurable increase in a non-target lesion, or the appearance of new lesions.
Time frame: Assessed up to 190 months
Duration of Clinical Benefit
Time from first assessment of clinical benefit to progression or death. Response is defined using Response Evaluation Criteria In Solid Tumors Criteria (RECIST v1.0), as either disappearance of all lesions or a \>=30% decrease in the sum of the longest diameter of target lesions with no progressing non-target lesions and no new lesions. Stable disease is neither responding or progressing. Progression is defined using Response Evaluation Criteria In Solid Tumors Criteria (RECIST v1.0), as a 20% increase in the sum of the longest diameter of target lesions, or a measurable increase in a non-target lesion, or the appearance of new lesions. Clinical benefit = (CR+PR)+(SD\>=6months).
Time frame: Assessed up to 190 months
Time to Treatment Failure
Time from randomisation to discontinuation of protocol treatment for any reason, or progression of disease
Time frame: To discontinuation of protocol treatment for any reason, or progression of disease assessed up to 190 months
Overall Survival
Time from randomisation until death from any cause.
Time frame: To death assessed up to 190 months.
Tolerability of Treatment
To evaluate the overall safety and tolerability. The number of patients experiencing at least one adverse event. Refer to adverse event section for more details.
Time frame: From start of treatment to discontinuation of treatment/progression assessed up to 190 months
Patients were recruited between 26 March 2004 and 6 August 2010 from 82 hospitals in the UK.
| Milestone | Faslodex + Placebo | Faslodex + Arimidex | Exemestane |
|---|---|---|---|
| Started | 226 | 233 | 239 |
| Completed | 226 | 233 | 238 |
| Not completed | 0 | 0 | 1 |
defined as time from randomisation to progression of existing disease, new sites of disease, second primary cancer if change in systemic treatment was necessary, or death from any cause. Progression is defined using Response Evaluation Criteria In Solid Tumors Criteria (RECIST v1.0), as a 20% increase in the sum of the longest diameter of target lesions, or a measurable increase in a non-target lesion, or the appearance of new lesions.
| Months | Faslodex + Placebo | Faslodex + Arimidex | Exemestane |
|---|---|---|---|
| Progression-free Survival | 4.8 (3.5 to 5.6) | 4.1 (3.2 to 5.3) | 3.5 (3.0 to 4.9) |
The proportion of patients identified as having a complete response (CR) or partial response (PR) at any time whilst on study treatment. Response is defined using Response Evaluation Criteria In Solid Tumors Criteria (RECIST v1.0), as either disappearance of all lesions or a \>=30% decrease in the sum of the longest diameter of target lesions with no progressing non-target lesions and no new lesions. Objective Response (OR) = CR + PR
| Participants | Faslodex + Placebo | Faslodex + Arimidex | Exemestane |
|---|---|---|---|
| Objective Response Rate | 16 | 17 | 10 |
time from first assessment of response to progression or death. Response is defined using Response Evaluation Criteria In Solid Tumors Criteria (RECIST v1.0), as either disappearance of all lesions or a \>=30% decrease in the sum of the longest diameter of target lesions with no progressing non-target lesions and no new lesions. Progression is defined using Response Evaluation Criteria In Solid Tumors Criteria (RECIST v1.0), as a 20% increase in the sum of the longest diameter of target lesions, or a measurable increase in a non-target lesion, or the appearance of new lesions.
| Months | Faslodex + Placebo | Faslodex + Arimidex | Exemestane |
|---|---|---|---|
| Duration of Response | 10.2 (2.6 to 18.4) | 8.7 (3.0 to 12.2) | 12.8 (6.2 to 33.4) |
Complete or partial response or stable disease for at least six months prior to progression. Response is defined using Response Evaluation Criteria In Solid Tumors Criteria (RECIST v1.0), as either disappearance of all lesions or a \>=30% decrease in the sum of the longest diameter of target lesions with no progressing non-target lesions and no new lesions. Stable disease is neither responding or progressing. Progression is defined using Response Evaluation Criteria In Solid Tumors Criteria (RECIST v1.0), as a 20% increase in the sum of the longest diameter of target lesions, or a measurable increase in a non-target lesion, or the appearance of new lesions.
| Participants | Faslodex + Placebo | Faslodex + Arimidex | Exemestane |
|---|---|---|---|
| Clinical Benefit Rate | 55 | 66 | 57 |
Time from first assessment of clinical benefit to progression or death. Response is defined using Response Evaluation Criteria In Solid Tumors Criteria (RECIST v1.0), as either disappearance of all lesions or a \>=30% decrease in the sum of the longest diameter of target lesions with no progressing non-target lesions and no new lesions. Stable disease is neither responding or progressing. Progression is defined using Response Evaluation Criteria In Solid Tumors Criteria (RECIST v1.0), as a 20% increase in the sum of the longest diameter of target lesions, or a measurable increase in a non-target lesion, or the appearance of new lesions. Clinical benefit = (CR+PR)+(SD\>=6months).
| months | Faslodex + Placebo | Faslodex + Arimidex | Exemestane |
|---|---|---|---|
| Duration of Clinical Benefit | 11.2 (8.2 to 16.9) | 11.5 (8.0 to 16.3) | 12.2 (8.9 to 23.8) |
Time from randomisation to discontinuation of protocol treatment for any reason, or progression of disease
| Months | Faslodex + Placebo | Faslodex + Arimidex | Exemestane |
|---|---|---|---|
| Time to Treatment Failure | 3.8 (3.1 to 5.4) | 3.9 (3.0 to 4.7) | 3.4 (3.1 to 4.5) |
Time from randomisation until death from any cause.
| Months | Faslodex + Placebo | Faslodex + Arimidex | Exemestane |
|---|---|---|---|
| Overall Survival | 20.1 (17.8 to 23.3) | 20.2 (17.0 to 22.6) | 22.5 (20.1 to 24.6) |
To evaluate the overall safety and tolerability. The number of patients experiencing at least one adverse event. Refer to adverse event section for more details.
| Participants | Faslodex + Placebo | Faslodex + Arimidex | Exemestane |
|---|---|---|---|
| Tolerability of Treatment | 221 | 227 | 230 |
Collected over Collected from the date each patient commenced treatment. AEs were collected every month for the first six months of the protocol and then every three months until disease progression/treatment discontinuation (assessed up to 190 months).. Non-serious events are listed at a 5% frequency threshold.
| Group | Deaths | Serious | Other |
|---|---|---|---|
| Faslodex + Placebo | 221/226 (97.8%) | 31/225 (13.8%) | 221/225 (98.2%) |
| Faslodex + Arimidex | 225/233 (96.6%) | 39/231 (16.9%) | 227/231 (98.3%) |
| Exemestane | 227/239 (95%) | 37/237 (15.6%) | 230/237 (97%) |
| Event | Faslodex + Placebo | Faslodex + Arimidex | Exemestane |
|---|---|---|---|
| DyspnoeaRespiratory, thoracic and mediastinal disorders | 7/225 | 2/231 | 3/237 |
| nauseaGastrointestinal disorders | 2/225 | 4/231 | 2/237 |
| Pulmonary embolismRespiratory, thoracic and mediastinal disorders | 1/225 | 4/231 | 1/237 |
| VomitingGastrointestinal disorders | 3/225 | 3/231 | 2/237 |
| FatigueGeneral disorders | 3/225 | 0/231 | 1/237 |
| PneumoniaInfections and infestations | 3/225 | 0/231 | 3/237 |
| Confusional statePsychiatric disorders | 3/225 | 1/231 | 0/237 |
| PalpitationsCardiac disorders | 0/225 | 3/231 | 0/237 |
| HypercalcaemiaMetabolism and nutrition disorders | 0/225 | 3/231 | 0/237 |
| Chest painGeneral disorders | 1/225 | 0/231 | 3/237 |
| Event | Faslodex + Placebo | Faslodex + Arimidex | Exemestane |
|---|---|---|---|
| LethargyGeneral disorders | 145/225 | 149/231 | 133/237 |
| ArthralgiaMusculoskeletal and connective tissue disorders | 98/225 | 97/231 | 110/237 |
| VomitingGastrointestinal disorders | 101/225 | 81/231 | 91/237 |
| Hot FlushReproductive system and breast disorders | 81/225 | 86/231 | 79/237 |
| InsomniaPsychiatric disorders | 64/225 | 76/231 | 70/237 |
| decreased appetiteMetabolism and nutrition disorders | 67/225 | 72/231 | 68/237 |
| DyspepsiaGastrointestinal disorders | 59/225 | 51/231 | 70/237 |
| HeadacheNervous system disorders | 65/225 | 51/231 | 51/237 |
| ConstipationGastrointestinal disorders | 57/225 | 64/231 | 57/237 |
| Mood alteredPsychiatric disorders | 59/225 | 55/231 | 59/237 |
ITT
| Age, Continuous(years) | Faslodex + Placebo | Faslodex + Arimidex | Exemestane | Total |
|---|---|---|---|---|
| Median | 63.2 (57.0 to 73.6) | 64.1 (57.6 to 72.3) | 66.1 (59.2 to 75.3) | 64.7 (58.0 to 73.5) |
| Age, Customized(Participants) | Faslodex + Placebo | Faslodex + Arimidex | Exemestane | Total |
|---|---|---|---|---|
| <50 years | 17 | 21 | 7 | 45 |
| 50 to 64 years | 102 | 104 | 100 | 306 |
| 65 to 74 years | 61 | 65 | 70 | 196 |
| >=75 years | 46 | 43 | 62 | 151 |
| Sex: Female, Male(Participants) | Faslodex + Placebo | Faslodex + Arimidex | Exemestane | Total |
|---|---|---|---|---|
| Female | 226 | 233 | 239 | 698 |
| Male | 0 | 0 | 0 | 0 |
| Race and Ethnicity Not Collected(Participants) | Faslodex + Placebo | Faslodex + Arimidex | Exemestane | Total |
|---|---|---|---|---|
| Count of participants | — | — | — | 0 |
| Region of Enrollment(participants) | Faslodex + Placebo | Faslodex + Arimidex | Exemestane | Total |
|---|---|---|---|---|
| United Kingdom | 226 | 233 | 239 | 698 |
| Hormone Receptor Status of primary disease(Participants) | Faslodex + Placebo | Faslodex + Arimidex | Exemestane | Total |
|---|---|---|---|---|
| ER+ve PR+ve | 121 | 111 | 123 | 355 |
| ER+ve PR -ve | 31 | 38 | 22 | 91 |
| ER+ve PR unknown | 71 | 83 | 91 | 245 |
| ER-ve/unknown PR+ve | 0 | 1 | 2 | 3 |
| ER unknown PR unknown | 2 | 0 | 1 | 3 |
| ER-ve PR-ve | 1 | 0 | 0 | 1 |
| HER2 Status of primary disease(Participants) | Faslodex + Placebo | Faslodex + Arimidex | Exemestane | Total |
|---|---|---|---|---|
| HER2 +ve | 14 | 15 | 15 | 44 |
| HER2 -ve | 136 | 117 | 134 | 387 |
| HER2 unknown | 76 | 101 | 90 | 267 |
| Time from primary diagnosis to first relapse(years) | Faslodex + Placebo | Faslodex + Arimidex | Exemestane | Total |
|---|---|---|---|---|
| Median | 5.1 (2.3 to 9.6) | 5.0 (2.0 to 10.0) | 5.2 (1.9 to 10.3) | 5.1 (2.1 to 10.0) |
Documents are hosted by the registry — open the source record to download them.
Plan to share: Yes — De-identified individual participant data, together with a data dictionary defining each field in the set, will be made available to other researchers on request, subject to the approval of a formal data access request in accordance with the ICR-CTSU data and sample access policy. Trial documentation including the protocol are available on request by contacting Formal requests for data sharing are considered in line with ICR-CTSU procedures. Requests are via a standard proforma describing the nature of the proposed research and extent of data requirements. Contact sofea-icrctsu@icr.ac.uk or visit the link below for further information.
Supporting information: Study protocol, Sap, Icf
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Institute of Cancer Research, United Kingdom