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OP-1250 (Palazestrant) vs. Standard of Care for the Treatment of ER+/HER2- Advanced Breast Cancer (OPERA-01)

A phase 3 randomized, open-label study of OP-1250 monotherapy vs standard of care for the treatment of ER+, HER2– advanced or metastatic breast cancer following endocrine and CDK 4/6 inhibitor therapy (OPERA-01)

Breast cancer, Locally advanced and metastatic breast cancer
All genders
person-wave 18+
Recruiting now
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Principal Investigator: Rachel Buchsbaum, MD

The purpose of this study is to determine whether treatment with OP-1250 as a monotherapy will result in improvement of progression-free survival (PFS) and overall survival (OS) compared to SOC ET and assess the safety of treatment with OP-1250 in participants with ER+, HER2– advanced or MBC with and without estrogen receptor 1 gene (ESR1) activating mutation(-s) whose disease has relapsed or progressed on 1 or 2 prior lines of SOC ET, including a cyclin-dependent kinase (CDK) 4/6 inhibitor.

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Latoya Lashley

Study details

Inclusion Criteria
  • 1. ER+, HER2- locally advanced or metastatic breast cancer that is not amenable to curative therapy.
  • 2. Evaluable disease (measurable disease or bone-only disease).
  • 3. Previously received a CDK4/6 inhibitor in combination with an endocrine therapy in the advanced setting. One additional line of ET as a monotherapy will be allowed.
Exclusion Criteria
  • 1. Symptomatic visceral disease, imminent organ failure, or any disease burden that makes the participant ineligible for endocrine therapy.
  • 2. Have received prior chemotherapy in the advanced/metastatic setting.
  • 3. Have received prior treatment with elacestrant or an investigational estrogen receptor-directed therapy.
Study Requirements

Subjects will either be treated with OP-1250 once daily on a 4 week (28 day) cycle OR Subjects will receive Investigator's choice of one of the Standard of Care drugs (fulvestrant, anastrozole, letrozole, or exemestane). During the study treatment period, you will have visits with your study doctor to see how you are doing and how you are responding to the study treatment. These visits will be more frequent at the beginning of treatment. You will undergo procedures at various times during these visits. Study participation may last about 24 months. How long you will stay in this study depends on how well you tolerate the study treatment and how your cancer responds to the treatment.

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