Trial Outcomes & Findings for Estradiol in Treating Patients With ER Beta Positive, Triple Negative Locally Advanced or Metastatic Breast Cancer (NCT NCT03941730)

Estradiol in Treating Patients With ER Beta Positive, Triple Negative Locally Advanced or Metastatic Breast Cancer

A patient is said to have derived clinical benefit rate at the 6 month time point if the patient's disease meets the Response Evaluation Criteria in Solid Tumors (RECIST) for complete response (CR), partial response (PR), or stable disease (SD) for \> 6 months following initiation of treatment. The 6 month clinical benefit rate is the percentage of patients who are found to meet the criteria for clinical benefit at least 6 months among all the patients who have started estradiol treatment. As the number of patients with discordant ERbeta findings are expected to be small, a 90% exact binomial confidence interval will be constructed for the proportion of patients who were found to have no to weak ERβbeta expressing metastatic triple-negative breast cancer (TNBC) and who derived clinical benefit rate at the 6 month time point.

An adverse event (AE) is any unfavorable and unintended sign (including an abnormal laboratory finding), symptom, or disease temporally associated with the use of a medical treatment or procedure that may or may not be considered related to the medical treatment or procedure. All grade 2, 3, 4 or 5 adverse events will be documented and assigned an attribute by treating clinician as to its relationship to treatment. For a given AE, the proportion of patients who report developing a grade 2-5 of this AE are determined. The number of dose reductions per patient and the reasons for the dose reduction are summarized.

The tumor response rate is defined as the 100% time the number of patients with a CR or PR (as defined by the RECIST criteria) on 2 consecutive evaluations at least 8 weeks apart divided by the total number of eligible patients who began study treatment. A 90% binomial confidence interval is constructed for the true response rate.

PFS is defined as the time from registration to the first of the following events: local, regional, or distant recurrence, second primary disease of death due to any cause. The distribution of PFS times will be estimated using the method of Kaplan-Meier.

OS is defined as the time from registration to death due to any cause. The distribution of survival times are estimated using the method of Kaplan-Meier.

Patients undergo tumor biopsies prior to the start of treatment and at completion of cycle 1 treatment. These specimens will be undergoing immunohistochemistry (IHC) staining with the following antibodies: phosphorylated (phospho)-ERbeta, cystatins 1, 2, 4 and 5, phospho-Smad2/3 and Ki-67. For each of these biomarkers, a times series plot are constructed so that an individual patient's data will be represented using the same color for each of the five graphs. These graphs are visually inspected for trends within each of the graphs (variation between individuals) as well as across the five graphs (profile of biomarker changes within an individual).

Change in cystatin levels following one cycle of treatment are examined using signed rank tests and the difference in the percent change in its level following one cycle of treatment between patients who derived clinical benefit and those who did not will be examined using a two sample Wilcoxon rank sum test.