Skip to content

Anastrozole and Letrozole After Surgery for the Treatment of Stage I-III Breast Cancer

Pharmacodynamic Study of Estrogen Suppression Threshold-Directed Therapy (ESTDT) of Anastrozole as Adjuvant Therapy for Early Stage Breast Cancer

Status
Completed
Phases
Phase 2
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT04294225
Enrollment
161
Registered
2020-03-04
Start date
2020-04-28
Completion date
2022-12-12
Last updated
2025-01-28

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Anatomic Stage IA Breast Cancer AJCC v8, Anatomic Stage IB Breast Cancer AJCC v8, Anatomic Stage I Breast Cancer AJCC v8, Anatomic Stage IIA Breast Cancer AJCC v8, Anatomic Stage IIB Breast Cancer AJCC v8, Anatomic Stage II Breast Cancer AJCC v8, Anatomic Stage IIIA Breast Cancer AJCC v8, Anatomic Stage IIIB Breast Cancer AJCC v8, Anatomic Stage III Breast Cancer AJCC v8, Anatomic Stage IIIC Breast Cancer AJCC v8, Early-Stage Breast Carcinoma, Invasive Breast Carcinoma, Prognostic Stage IA Breast Cancer AJCC v8, Prognostic Stage IB Breast Cancer AJCC v8, Prognostic Stage I Breast Cancer AJCC v8, Prognostic Stage IIA Breast Cancer AJCC v8, Prognostic Stage IIB Breast Cancer AJCC v8, Prognostic Stage II Breast Cancer AJCC v8, Prognostic Stage IIIA Breast Cancer AJCC v8, Prognostic Stage IIIB Breast Cancer AJCC v8, Prognostic Stage III Breast Cancer AJCC v8, Prognostic Stage IIIC Breast Cancer AJCC v8

Brief summary

This phase II trial studies how well anastrozole and letrozole after surgery work in treating patients with stage I-III breast cancer. Drugs, such as anastrozole and letrozole, may stop the growth of tumor cells by decreasing the amount of estrogen made by the body. Giving anastrozole and letrozole after surgery may prevent breast cancer from coming back (recurrence).

Detailed description

PRIMARY OBJECTIVE: I. To estimate the proportion of women who have adequate estrone (E1) and estradiol (E2) suppression after 8-10 weeks of adjuvant anastrozole 10 mg once daily (ANA10) having had inadequate E1 and E2 suppression after 8-10 weeks of standard dose anastrozole 1 mg once daily (ANA1). SECONDARY OBJECTIVES: I. To estimate the proportion of women with elevated E1 and E2 levels after 8-10 weeks of adjuvant ANA1. II. To estimate the proportion of women with elevated E1 and E2 levels after 8-10 weeks of adjuvant ANA1 whose E1 and E2 levels remain elevated after 8-10 weeks of adjuvant ANA10. III. To examine the toxicity profile of ANA1 over the 8-10 weeks of treatment, ANA10 over the 8-10 weeks of treatment, and letrozole over the 8-10 weeks of treatment. IV. To examine concentrations of anastrozole at both the ANA1 and ANA10 dose levels. V. To examine E1 and E2 concentrations, as well as letrozole drug levels, in patients receiving letrozole (following ANA10). VI. To bank deoxyribonucleic acid (DNA) for examination of single-nucleotide polymorphism (SNP)-set(s) determined in the ongoing Mayo Clinic Breast Cancer Specialized Program of Research Excellence (SPORE) Project 4. EXPLORATORY OBJECTIVE: I. To examine association between clinical variables such as age, age at menopause, body mass index (BMI), receipt of chemotherapy, chemotherapy regimen, and dose on E1 and E2 levels after 8-10 weeks of ANA10. OUTLINE: Patients receive anastrozole orally (PO) once daily (QD) for 56-70 days (8-10 weeks). Patients with E1 \>= 1.3 pg/ml and E2 \>= 0.5 pg/ml continue to receive anastrozole PO QD for another 56-70 days (8-10 weeks). Patients then receive letrozole PO QD for 8-10 weeks. Treatment continues in the absence of disease progression or unacceptable toxicity.

Interventions

DRUGAnastrozole

Given PO

DRUGLetrozole

Given PO

Sponsors

National Cancer Institute (NCI)
CollaboratorNIH
Mayo Clinic
Lead SponsorOTHER

Study design

Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
TREATMENT
Masking
NONE

Eligibility

Sex/Gender
FEMALE
Age
18 Years to No maximum
Healthy volunteers
No

Inclusion criteria

* REGISTRATION-INCLUSION CRITERIA * Disease characteristics: * Histological confirmation of invasive breast carcinoma * Stage I-III breast cancer * Estrogen receptor (ER) positive disease according to American Society of Clinical Oncology (ASCO)/College of American Pathologists (CAP) guidelines as ER \>= 1% positive nuclear staining * Completion of all planned cancer treatments prior to registration: * Surgical resection of breast and nodal surgery; (NOTE: Reconstructive surgery does not have to be completed) * Adjuvant radiation therapy, if needed * Neoadjuvant and/or adjuvant chemotherapy, if needed * Post-menopausal defined as * Age \>= 60 and amenorrhea \> 12 consecutive months OR * Previous bilateral oophorectomy OR * Age \< 60 and amenorrhea \> 12 consecutive months and documented follicle stimulating hormone (FSH) level within post-menopausal range according to institutional standard * NOTE: Patients who did not meet these criteria at time of diagnosis and received pre-operative (neoadjuvant) or post-operative (adjuvant) chemotherapy will not be allowed to participate * Eastern Cooperative Oncology Group (ECOG) performance status (PS) 0, 1, or 2 * Hemoglobin \>= 8.0 g/dL (obtained =\< 14 days prior to registration) * Absolute neutrophil count (ANC) \>= 1500/mm\^3 (obtained =\< 14 days prior to registration) * Platelet count \>= 70,000/mm\^3 (obtained =\< 14 days prior to registration) * Total bilirubin =\< 1.5 x upper limit of normal (ULN) (obtained =\< 14 days prior to registration) * Alanine aminotransferase (ALT) and aspartate transaminase (AST) =\< 3 x ULN (obtained =\< 14 days prior to registration) * Ability to swallow oral medication * Provide written informed consent * Willingness to provide mandatory blood specimens for correlative research * Willing to return to enrolling institution for follow-up (during the Active Monitoring Phase of the study) * RE-REGISTRATION-INCLUSION CRITERIA * Confirmation that baseline blood sample was drawn and submitted * Blood estrogen levels after cycle 1 anastrozole (ANA1) must meet the following criteria: * E1 \>= 1.3 pg/ml, AND * E2 \>= 0.5 pg/ml

Exclusion criteria

* REGISTRATION-

Design outcomes

Primary

MeasureTime frameDescription
Percentage of Participants With Adequate Estrogen Suppression After 8 Weeks of Adjuvant Anastrozole 10 mg Daily24 weeksPercentage of women who have adequate E1 and E2 suppression (E1 \< 1.3 pg/ml and/or E2 \< 0.5) after 8-10 weeks of adjuvant anastrozole 10 mg daily having had inadequate E1 and E2 (E1 \>= 1.3 pg/ml and E2 \>= 0.5) after 8-10 weeks of adjuvant anastrozole 1 mg daily.

Secondary

MeasureTime frameDescription
Number of Participants Experiencing a Grade 3 or Greater Adverse Event24 weeksPatients will be assessed by National Cancer Institute Common Terminology Criteria for Adverse Events version 5.0. Patients were to receive anastrozole 1 mg daily for 8 weeks (ANA1). After 8 weeks of ANA1, patients with E1 \< 1.3 pg/ml and/or E2 \< 0.5 pg/ml completed study and patients with E1 \>= 1.3 pg/ml and E2 \>= 0.5 pg/ml were to switch to anastrozole 10 mg daily (ANA10) for 8 weeks. After 8 weeks of ANA10, patients were to switch to letrozole 2.5 mg daily for 8 weeks. E1 and E2 levels were measured after this 8 week period. Patients were then go off study
Percent Change in Estrone (E1) and Estradiol (E2) Concentrations24 weeksDescriptive statistics will be used. The median percent change in E1 and E2 concentrations from pre-AI levels will be presented.

Countries

United States

Participant flow

Participants by arm

ArmCount
Treatment (Anastrozole, Letrozole)
Patients were to receive anastrozole 1 mg daily for 8 weeks (ANA1). After 8 weeks of ANA1, patients with E1 \< 1.3 pg/ml and/or E2 \< 0.5 pg/ml completed study and patients with E1 \>= 1.3 pg/ml and E2 \>= 0.5 pg/ml were to switch to anastrozole 10 mg daily (ANA10) for 8 weeks. After 8 weeks of ANA10, patients were to switch to letrozole 2.5 mg daily for 8 weeks. E1 and E2 levels were measured after this 8 week period. Patients were then go off study
156
Total156

Withdrawals & dropouts

PeriodReasonFG000
Anastrozole 10 mg/DayWithdrawal by Subject1
Anastrozole 1 mg/DayDiscontinued due to adverse events3
Anastrozole 1 mg/DayDiscontinued due to COVID1
Anastrozole 1 mg/DayIneligible2
Anastrozole 1 mg/DayWithdrawal by Subject5

Baseline characteristics

CharacteristicTreatment (Anastrozole, Letrozole)
Age, Customized
Age at registration (years)
40-49
5 Participants
Age, Customized
Age at registration (years)
50-59
46 Participants
Age, Customized
Age at registration (years)
60-69
62 Participants
Age, Customized
Age at registration (years)
70-79
35 Participants
Age, Customized
Age at registration (years)
80-89
8 Participants
BMI
Obese
62 Participants
BMI
Overweight
54 Participants
BMI
Underweight/Normal
36 Participants
BMI
Unknown
4 Participants
ECOG Performance Status
0
148 Participants
ECOG Performance Status
1
8 Participants
Ethnicity (NIH/OMB)
Hispanic or Latino
5 Participants
Ethnicity (NIH/OMB)
Not Hispanic or Latino
149 Participants
Ethnicity (NIH/OMB)
Unknown or Not Reported
2 Participants
Race (NIH/OMB)
American Indian or Alaska Native
3 Participants
Race (NIH/OMB)
Asian
3 Participants
Race (NIH/OMB)
Black or African American
4 Participants
Race (NIH/OMB)
More than one race
0 Participants
Race (NIH/OMB)
Native Hawaiian or Other Pacific Islander
0 Participants
Race (NIH/OMB)
Unknown or Not Reported
0 Participants
Race (NIH/OMB)
White
146 Participants
Region of Enrollment
United States
156 participants
Sex: Female, Male
Female
156 Participants
Sex: Female, Male
Male
0 Participants

Adverse events

Event typeEG000
affected / at risk
EG001
affected / at risk
EG002
affected / at risk
deaths
Total, all-cause mortality
0 / 1560 / 330 / 24
other
Total, other adverse events
120 / 15626 / 3320 / 24
serious
Total, serious adverse events
4 / 1561 / 330 / 24

Outcome results

Primary

Percentage of Participants With Adequate Estrogen Suppression After 8 Weeks of Adjuvant Anastrozole 10 mg Daily

Percentage of women who have adequate E1 and E2 suppression (E1 \< 1.3 pg/ml and/or E2 \< 0.5) after 8-10 weeks of adjuvant anastrozole 10 mg daily having had inadequate E1 and E2 (E1 \>= 1.3 pg/ml and E2 \>= 0.5) after 8-10 weeks of adjuvant anastrozole 1 mg daily.

Time frame: 24 weeks

Population: Only participants that received anastrozole 10 mg daily (ANA10) and were adherent (reported taking ANA10 for 45-84 days) to treatment were analyzed

ArmMeasureValue (NUMBER)
Treatment (Anastrozole, Letrozole)Percentage of Participants With Adequate Estrogen Suppression After 8 Weeks of Adjuvant Anastrozole 10 mg Daily76.0 percentage of participants
Secondary

Number of Participants Experiencing a Grade 3 or Greater Adverse Event

Patients will be assessed by National Cancer Institute Common Terminology Criteria for Adverse Events version 5.0. Patients were to receive anastrozole 1 mg daily for 8 weeks (ANA1). After 8 weeks of ANA1, patients with E1 \< 1.3 pg/ml and/or E2 \< 0.5 pg/ml completed study and patients with E1 \>= 1.3 pg/ml and E2 \>= 0.5 pg/ml were to switch to anastrozole 10 mg daily (ANA10) for 8 weeks. After 8 weeks of ANA10, patients were to switch to letrozole 2.5 mg daily for 8 weeks. E1 and E2 levels were measured after this 8 week period. Patients were then go off study

Time frame: 24 weeks

Population: Only participants that received treatment and were eligible were analyzed

ArmMeasureValue (COUNT_OF_PARTICIPANTS)
Treatment (Anastrozole, Letrozole)Number of Participants Experiencing a Grade 3 or Greater Adverse Event6 Participants
Anastrozolem10mg DailyNumber of Participants Experiencing a Grade 3 or Greater Adverse Event0 Participants
Letrozole 2.5 mg DailyNumber of Participants Experiencing a Grade 3 or Greater Adverse Event0 Participants
Secondary

Percent Change in Estrone (E1) and Estradiol (E2) Concentrations

Descriptive statistics will be used. The median percent change in E1 and E2 concentrations from pre-AI levels will be presented.

Time frame: 24 weeks

Population: Patients that received anastrozole 10 mg daily (ANA10) and were adherent to treatment were analyzed.

ArmMeasureGroupValue (MEDIAN)
Treatment (Anastrozole, Letrozole)Percent Change in Estrone (E1) and Estradiol (E2) ConcentrationsE1 levels-97.0 percent change
Treatment (Anastrozole, Letrozole)Percent Change in Estrone (E1) and Estradiol (E2) ConcentrationsE2 levels-94.6 percent change

Source: ClinicalTrials.gov · Data processed: Feb 4, 2026