This phase I trial studies the side effects and the best dose of Z-endoxifen hydrochloride in treating patients with estrogen receptor-positive (ER+) breast cancer that has spread to other places in the body (metastatic) or has come back at or near the same place as the original tumor (locally recurrent). Estrogen can cause the growth of breast cancer cells. Hormone therapy using Z-endoxifen hydrochloride may fight breast cancer by blocking the use of estrogen by tumor cells.
PRIMARY OBJECTIVES: l. To determine either the maximum-tolerated dose (MTD) of Z-endoxifen hydrochloride or the dose level associated with endoxifen steady state concentration (Css) of at least 2 uM in women with metastatic estrogen-receptor positive (ER+) breast cancer. (Dose Escalation Cohort) II. To describe the safety profile of Z-endoxifen (Z-endoxifen hydrochloride) at each of the doses examined. (Dose Escalation Cohort) III. To evaluate changes in vision after 2 cycles of treatment. (Dose Escalation Cohort) IV. To gather preliminary data on the clinical benefit in terms of tumor response rate and progression-free survival. (Dose Escalation Cohort) V. To evaluate the changes in the frequency and severity of hot flashes after 2 cycles of treatment. (Expansion Cohort) VI. Evaluate changes in irritability scale using a validated irritability questionnaire. (Expansion Cohort) VII. To evaluate changes in markers of bone formation and absorption after 2 cycles of treatment. (Expansion Cohort) XIII. To evaluate changes in vision after 2 cycles of treatment. (Expansion Cohort). IX. To further characterize the safety profile of Z-endoxifen. (Expansion Cohort) SECONDARY OBJECTIVES: I. To characterize the plasma pharmacokinetics and urinary excretion of Z-endoxifen at each of the doses examined. II. For patients beginning in dose level 7 as well as the expansion cohorts, we will describe any changes in tumor expression of ER (both full length and truncated forms), progesterone receptor (PR), steroid receptor co-activator (SRC)1, SRC3, as well as the insulin-like growth factor receptor (IGF)1R/phosphatidylinositol 3 kinase (PI3K)/v-akt Murine Thymoma Viral Oncogene Homolog 1 (AKT)/mammalian target of rapamycin (mTOR) pathway and proliferation-related Ki-67 antigen (Ki67) after 1 cycle of treatment (approximately 28 days). III. To determine the frequency of estrogen receptor 1 (ESR1) mutations and the presence of antitumor activity (response rate and progression free survival \[PFS\]) in all patients whose tumors harbor ESR1 alterations. IV. To determine whether the ESR1 mutations identified in pre-treatment tumor biopsies can be detected in matched plasma cell free deoxyribonucleic acid (DNA) from the same patients. OUTLINE: This is a dose-escalation study followed by an expansion cohort study. Patients receive Z-endoxifen hydrochloride orally (PO) on days 1-28. Courses repeat every 28 days in the absence of disease progression or unacceptable toxicity. After completion of study treatment, patients are followed up for 30 days and then at 3 months.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
TREATMENT
Masking
NONE
Enrollment
62
Given PO
Correlative studies
Correlative studies
Ancillary studies
Mayo Clinic in Arizona
Scottsdale, Arizona, United States
Mayo Clinic in Florida
Jacksonville, Florida, United States
Mayo Clinic in Rochester
Rochester, Minnesota, United States
MTD defined as the highest dose level where at most 1 of 6 patients develops a dose limiting toxicity and 2 or more of the 3-6 patients treated at the next higher dose level develop a dose limiting toxicity
Assessed using the National Cancer Institute Common Terminology Criteria for Adverse Events version 4.0. The maximum grade of each type of toxicity will be recorded for each patient. For each toxicity reported by dose level, the percentage of patients developing any degree of that toxicity as well as the percentage of patients developing a severe degree (grade 3 or higher) will be determined.
Time frame: 28 days
Progression-free survival
Time frame: From study entry to the documentation of disease progression, assessed up to 3 months
Overall survival
Time frame: From study entry to death due to any cause, assessed up to 3 months
Change in hot flash scores graded using a hot flash diary and the hot flash interference scale
The number and severity of hot flashes will be examined. Times series plots of hot flash scores will be constructed to visually assess changes across time within a dose level and between dose levels. In particular, for each expansion dose level, a 90% confidence interval will be constructed for the proportion of patients whose hot flash scores increase at least 2 fold from baseline after one course of treatment.
Time frame: Baseline to day 28
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