Title: Epigenetic priming for immune therapy in ER-positive breast cancer in biomarker select population

Principal Investigator: Pamela Munster, MD, of the University of California, San Francisco

Description: Researchers are conducting a phase 2 trial to determine the effects of adding vorinostat to treatment with pembrolizumab and tamoxifen in patients with stage IV estrogen receptor-positive breast cancer.

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In arm A, patients will receive pembrolizumab intravenously over 30 minutes on day 1, vorinostat orally once a day for 4 days a week, and tamoxifen orally every day of each 21-day cycle. 

In arm B, patients will receive pembrolizumab and tamoxifen on the same schedule but without vorinostat. Patients in both arms will continue to receive treatment until disease progression or unacceptable toxicity. 

The primary objective of this trial is to define the role of epigenetic immune priming in this patient population on the basis of overall response rate. Secondary outcomes include the duration of response, progression-free survival, and overall survival.

To be eligible for this trial, patients must be 18 years of age or older. They must have a cytologically or histologically confirmed diagnosis of stage IV, estrogen receptor-positive breast cancer. For a complete list of eligibility criteria, please see the reference.

Status: Recruiting

This trial is sponsored by the University of California, San Francisco, in collaboration with Merck Sharp & Dohme LLC.


ClinicalTrials.gov. Pembrolizumab and tamoxifen with or without vorinostat for the treatment of estrogen receptor positive breast cancer. NCT04190056. Accessed March 17, 2023.