Palazestrant: Participants will be treated with palazestrant once daily on a 4 week (28 day) cycle. Doses evaluated in the dose-selection part will be 120 mg once daily and 90 mg once daily.
Fulvestrant: Participants will be treated with fulvestrant on C1D1, C1D15, and then on Day 1 of every subsequent 4 week (28 day) cycle
Anastrozole: Participants will be treated with anastrozole once daily on a 4 week (28 day) cycle
Letrozole: Participants will be treated with letrozole once daily on a 4 week (28 day) cycle
Exemestane: Participants will be treated with exemestane once daily on a 4 week (28 day) cycle
Study summary
This phase 3 clinical trial compares the safety and efficacy of palazestrant (OP-1250) to the standard-of-care options of fulvestrant or an aromatase inhibitor in women and men with breast cancer whose disease has advanced on one endocrine therapy in combination with a CDK4/6 inhibitor.
Eligibility
Sex
ALL
Min age
18 Years
Max age
—
Healthy volunteers
No
Key inclusion criteria:
* Adult female or male participants.
* ER+, HER2- locally advanced or metastatic breast cancer that is not amenable to curative therapy.
* Evaluable disease (measurable disease or bone-only disease).
* Previously received a CDK4/6 inhibitor in combination with an endocrine therapy in the advanced setting. One additional line of ET as a monotherapy is allowed. Duration of the most recent prior ET must be at least 6 months.
* Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1.
* Adequate hematologic, hepatic, and renal functions.
* Female participants can be pre-, peri- or postmenopausal.
* Male and pre- or peri-menopausal female participants must be willing to take a GnRH (or LHRH) agonist.
Key exclusion criteria:
* Symptomatic visceral disease, imminent organ failure, or any other reason that makes the participant ineligible for endocrine monotherapy.
* Previously received chemotherapy in the advanced/metastatic setting.
* Previously received treatment with elacestrant or an investigational estrogen receptor-directed therapy.
* History of allergic reactions to study treatment.
* Any contraindications to the selected standard-of-care endocrine therapy in the local prescribing information.
* Symptomatic central nervous system metastases, carcinomatous meningitis, leptomeningeal disease, or a spinal cord compression that require immediate treatment.
* Clinically significant comorbidities such as significant cardiac or cerebrovascular disease, gastrointestinal disorders that could affect absorption of study treatment.
Primary outcome measure(s)
Dose-Selection Part: Incidence of adverse events — From Date of Randomization up to 16 weeks To evaluate the number of participants with adverse events
Dose-Selection Part: Incidence of dose reduction — From Date of Randomization up to 16 weeks To evaluate the number of participants reducing the dose of palazestrant
Dose-Selection Part: Incidence of drug discontinuation — From Date of Randomization up to 16 weeks To evaluate the number of participants discontinuing palazestrant
Trial: Progression-Free Survival (PFS) — From Date of Randomization until Disease Progression or Death Due to Any Cause (estimated as up to 2 years) To compare PFS, based on a Blinded Independent Review Committee (BIRC) assessment, between arms of OP-1250 and standard-of-care treatment. This will be assessed separately in populations of ESR1-mutation detected and ESR1-mutation not detected participants.
Trial sites (233)
Facility
City
Region
Status
Clinical Trial Site
Tucson
Arizona
Clinical Trial Site
Fountain Valley
California
Clinical Trial Site
Glendale
California
Clinical Trial Site
La Jolla
California
Clinical Trial Site
Los Alamitos
California
Clinical Trial Site
Los Angeles
California
Clinical Trial Site
Whittier
California
Clinical Trial Site
Aurora
Colorado
Clinical Trial Site
Denver
Colorado
Clinical Trial Site
Golden
Colorado
Clinical Trial Site
Grand Junction
Colorado
Clinical Trial Site
Danbury
Connecticut
Clinical Trial Site
Newark
Delaware
Clinical Trials Site
Jacksonville
Florida
Clinical Trial Site
Margate
Florida
Clinical Trial Site
Orlando
Florida
Clinical Trial Site
Plantation
Florida
Clinical Trial Site
Tamarac
Florida
Clinical Trial Site
Atlanta
Georgia
Clinical Trial Site
Chicago
Illinois
Clinical Trial Site
Chicago
Illinois
Clinical Trial Site
Urbana
Illinois
Clinical Trial Site
Baton Rouge
Louisiana
Clinical Trial Site
New Orleans
Louisiana
Clinical Trial Site
Baltimore
Maryland
Clinical Trial Site
Boston
Massachusetts
Clinical Trial Site
Detroit
Michigan
Clinical Trial Site
Saint Louis Park
Minnesota
Clinical Trial Site
Woodbury
Minnesota
Clinical Trial Site
Lincoln
Nebraska
Clinical Trial Site
Farmington
New Mexico
Clinical Trial Site
New York
New York
Clinical Trial Site
Port Jefferson Station
New York
Clinical Trial Site
Dayton
Ohio
Clinical Trial Site
Toledo
Ohio
Clinical Trial Site
Portland
Oregon
Clinical Trial Site
Sayre
Pennsylvania
Clinical Trial Site
Nashville
Tennessee
Clinical Trial Site
Nashville
Tennessee
Clinical Trial Site
Nashville
Tennessee
+ 193 more sites — see the full list on the official registry below.
This page summarises publicly available registry data for informational purposes — not medical advice. Eligibility is determined by each study team; patients should discuss participation with their clinician.
We use cookies to analyse site traffic and improve your experience. With your consent, we may also use cookies for advertising. You can change your choice at any time on our Cookie Policy page. See also our Privacy Policy.