This phase II trial studies how well pembrolizumab and tamoxifen with or without vorinostat work for the treatment of estrogen receptor positive breast cancer. Immunotherapy with monoclonal antibodies, such as pembrolizumab, may help the body's immune system attack the cancer, and may interfere with the ability of tumor cells to grow and spread. Estrogen can cause the growth of breast cancer cells. Hormone therapy with tamoxifen may may fight breast cancer by blocking the use of estrogen by the tumor cells. Vorinostat may stop the growth of tumor cells by blocking some of the enzymes needed for cell growth. This trial is being done to find a drug combination to better control estrogen receptor positive breast cancer and reduce the number of pills taken.
PRIMARY OBJECTIVE: I. To define the role of epigenetic immune priming in a biomarker enriched estrogen receptor (ER)+ breast cancer population on the basis of overall response rate. SECONDARY OBJECTIVES: I. To assess duration of response (DOR) 24-week landmark progression-free survival (PFS:24). II. Median PFS and overall survival (OS). III. Tumor responses will also be calculated by Immune Related Response-Criteria (irRC). EXPLORATORY OBJECTIVES: I. Evaluation of biomarker target threshold on response rate (retrospective cut off of 20% versus \[vs\] 10%). II. To assess the ratio of effector T cells: regulatory T cells in blood and tumor biopsies pre- and post-therapy. III. To evaluate inflammatory T cell signature changes in blood and tumor biopsies pre- and post-therapy. IV. To evaluate changes in number of myeloid-derived suppressor cells (MDSCs) in peripheral blood and tumor biopsies pre- and posttherapy. V. To evaluate changes in histone acetylation in peripheral blood cells and tumor biopsies pre- and post-therapy. VI. Initial comparison to vorinostat-induced PD-1 in lymphocytes, PD-L1 modulation. VII. Nanostring and 10 x sequencing and single cell immune phenotyping (on stored tissue for successful arms only). VIII. Impact of histone deacetylase (HDAC) inhibition of response to pembrolizumab vs. pembrolizumab in biomarker enriched population. OUTLINE: Patients are randomized to 1 of 2 arms. ARM A: Patients receive pembrolizumab intravenously (IV) over 30 minutes on day 1, vorinostat orally (PO) once daily (QD) for 4 days weekly, and tamoxifen PO QD on days 1-21. Cycles repeat every 21 days in the absence of disease progression of unacceptable toxicity. ARM B: Patients receive pembrolizumab IV over 30 minutes on day 1 and tamoxifen PO QD on days 1-21. Cycles repeat every 21 days in the absence of disease progression of unacceptable toxicity. After completion of study treatment, patients are followed up for 30 days and then every 12 weeks thereafter.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
NONE
Enrollment
1
University of California, San Francisco
San Francisco, California, United States
Overall Response Rate (ORR)
ORR is defined as the proportion of participants randomized to that arm whose status is stable disease (SD) or better (complete response (CR), partial response (PR)). Per Response Evaluation Criteria In Solid Tumors Criteria (RECIST v1.0) for target lesions: CR=Disappearance of all target lesions; PR = \>=30% decrease in the sum of the longest diameter of target lesions, and SD=Neither sufficient shrinkage to qualify for PR nor sufficient increase to qualify for progressive disease,.
Time frame: Up to 24 weeks
Percentage of Participants With Tumor Responses
Tumor responses will be classified using the Immune Related Response-Criteria (irRC)) through study completion.
Time frame: Up to 24 months
Duration of Response (DOR)
The duration of overall response is measured from the time measurement criteria are met for CR or PR (whichever is first recorded) until the first date that recurrent or progressive disease is objectively documented (taking as reference for progressive disease the smallest measurements recorded since the treatment started). The duration of overall CR is measured from the time measurement criteria are first met for CR until the first date that recurrent disease is objectively documented. Duration of stable disease is measured from the start of the treatment until the criteria for progression are met, taking as reference the smallest measurements recorded since the treatment started. Will use median DOR (computed by the Kaplan-Meier estimator) to summarize. The respective confidence intervals will be computed as well.
Time frame: Up to 24 weeks
Median Progression Free Survival (PFS)
Progression-free survival (PFS) is defined as the duration of time from start of treatment to time of progression or death from any cause on study, whichever occurs first. Will use median PFS (computed by the Kaplan-Meier estimator) to summarize. The respective confidence intervals will be computed as well.
Time frame: Up to 27 months
Median Overall Survival (OS)
Will use median OS (computed by the Kaplan-Meier estimator) to summarize from initiation of study treatment to the time of death from any cause on study. The respective confidence intervals will be computed as well.
Time frame: Up to 27 months
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