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

NCT ID: NCT06016738

Last Updated: 2025-08-29

Study Results

Results pending

The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.

Basic Information

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Recruitment Status

RECRUITING

Clinical Phase

PHASE3

Total Enrollment

510 participants

Study Classification

INTERVENTIONAL

Study Start Date

2023-11-16

Study Completion Date

2027-09-30

Brief Summary

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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.

Detailed Description

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This is an international, multicenter, randomized, open-label, active-controlled, phase 3 clinical trial. The purpose of this trial is to compare the safety and efficacy of palazestrant (OP-1250) as a single agent to the standard of care endocrine therapy: either fulvestrant or an aromatase inhibitor (anastrozole, letrozole, or exemestane).

This trial is seeking adult participants with ER+, HER2- advanced or metastatic breast cancer whose disease has relapsed or progressed on 1 or 2 prior lines of standard-of-care endocrine therapy for metastatic breast cancer. Prior lines of therapy must include one line of endocrine therapy in combination with a CDK 4/6 inhibitor. In the dose-selection part of the trial, approximately 120 participants will be randomized to one of the two doses of palazestrant or to the standard-of-care endocrine therapy. Thereafter, approximately 390 participants will be randomized to palazestrant at the selected dose or to the standard-of-care endocrine therapy.

Conditions

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Breast Cancer Advanced Breast Cancer Metastatic Breast Cancer ER Positive Breast Cancer HER2 Negative Breast Carcinoma

Study Design

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Allocation Method

RANDOMIZED

Intervention Model

PARALLEL

Primary Study Purpose

TREATMENT

Blinding Strategy

NONE

Study Groups

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Palazestrant (OP-1250)

Participants will receive Palazestrant

Group Type EXPERIMENTAL

Palazestrant

Intervention Type DRUG

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.

Standard of Care Endocrine Therapy

Participants will receive Investigator's choice of one of the Standard of Care drugs (fulvestrant, anastrozole, letrozole, or exemestane)

Group Type ACTIVE_COMPARATOR

Fulvestrant

Intervention Type DRUG

Participants will be treated with fulvestrant on C1D1, C1D15, and then on Day 1 of every subsequent 4 week (28 day) cycle

Anastrozole

Intervention Type DRUG

Participants will be treated with anastrozole once daily on a 4 week (28 day) cycle

Letrozole

Intervention Type DRUG

Participants will be treated with letrozole once daily on a 4 week (28 day) cycle

Exemestane

Intervention Type DRUG

Participants will be treated with exemestane once daily on a 4 week (28 day) cycle

Interventions

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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.

Intervention Type DRUG

Fulvestrant

Participants will be treated with fulvestrant on C1D1, C1D15, and then on Day 1 of every subsequent 4 week (28 day) cycle

Intervention Type DRUG

Anastrozole

Participants will be treated with anastrozole once daily on a 4 week (28 day) cycle

Intervention Type DRUG

Letrozole

Participants will be treated with letrozole once daily on a 4 week (28 day) cycle

Intervention Type DRUG

Exemestane

Participants will be treated with exemestane once daily on a 4 week (28 day) cycle

Intervention Type DRUG

Other Intervention Names

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OP-1250

Eligibility Criteria

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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.

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.
Minimum Eligible Age

18 Years

Eligible Sex

ALL

Accepts Healthy Volunteers

No

Sponsors

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Olema Pharmaceuticals, Inc.

INDUSTRY

Sponsor Role lead

Responsible Party

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Responsibility Role SPONSOR

Principal Investigators

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Medical Director, MD

Role: STUDY_DIRECTOR

Olema Pharmaceuticals, Inc.

Locations

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Clinical Trial Site

Tucson, Arizona, United States

Site Status RECRUITING

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Fountain Valley, California, United States

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La Jolla, California, United States

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Los Angeles, California, United States

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Whittier, California, United States

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Aurora, Colorado, United States

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Denver, Colorado, United States

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Golden, Colorado, United States

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Grand Junction, Colorado, United States

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Danbury, Connecticut, United States

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Newark, Delaware, United States

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Jacksonville, Florida, United States

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Margate, Florida, United States

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Orlando, Florida, United States

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Plantation, Florida, United States

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Tamarac, Florida, United States

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Atlanta, Georgia, United States

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Chicago, Illinois, United States

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Chicago, Illinois, United States

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Urbana, Illinois, United States

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Baton Rouge, Louisiana, United States

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New Orleans, Louisiana, United States

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Baltimore, Maryland, United States

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Boston, Massachusetts, United States

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Detroit, Michigan, United States

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Saint Louis Park, Minnesota, United States

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Lincoln, Nebraska, United States

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Farmington, New Mexico, United States

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New York, New York, United States

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Port Jefferson Station, New York, United States

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Dayton, Ohio, United States

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Toledo, Ohio, United States

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Portland, Oregon, United States

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Sayre, Pennsylvania, United States

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Nashville, Tennessee, United States

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Nashville, Tennessee, United States

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Dallas, Texas, United States

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Dallas, Texas, United States

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Houston, Texas, United States

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Ogden, Utah, United States

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Spokane, Washington, United States

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Spokane, Washington, United States

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Bahía Blanca, Buenos Aires, Argentina

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Mar del Plata, Buenos Aires, Argentina

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Mar del Plata, Buenos Aires, Argentina

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Córdoba, Córdoba Province, Argentina

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Córdoba, Córdoba Province, Argentina

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San Salvador de Jujuy, Jujuy Province, Argentina

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La Rioja, La Rioja Province, Argentina

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Viedma, Río Negro Province, Argentina

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Rosario, Santa Fe Province, Argentina

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Rosario, Santa Fe Province, Argentina

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San Miguel de Tucumán, Tucumán Province, Argentina

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Buenos Aires, , Argentina

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Gosford, New South Wales, Australia

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Westmead, New South Wales, Australia

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Adelaide, South Australia, Australia

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Ballarat Central, Victoria, Australia

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Clayton, Victoria, Australia

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Shepparton, Victoria, Australia

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Nedlands, Western Australia, Australia

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Edegem, Antwerpen, Belgium

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Woluwe-Saint-Lambert, Brussels Capital, Belgium

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Charleroi, Hainaut, Belgium

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Leuven, Vlaams Brabant, Belgium

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Salvador, Estado de Bahia, Brazil

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Belo Horizonte, Minas Gerais, Brazil

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Recife, Pernambuco, Brazil

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Porto Alegre, Rio Grande do Sul, Brazil

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Porto Alegre, Rio Grande do Sul, Brazil

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Itajaí, Santa Catarina, Brazil

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Sorocaba, São Paulo, Brazil

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Rio de Janeiro, , Brazil

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Panagyurishte, Pazardzhik, Bulgaria

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Sofia, Sofia-Grad, Bulgaria

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Vratsa, Vratsa, Bulgaria

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Calgary, Alberta, Canada

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London, Ontario, Canada

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Toronto, Ontario, Canada

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Montreal, Quebec, Canada

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Hradec Králové, Královéhradecký kraj, Czechia

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Nový Jičín, Moravskoslezský kraj, Czechia

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Olomouc, Olomoucký kraj, Czechia

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Bourg-en-Bresse, Ain, France

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Besançon, Doubs, France

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Nantes, Loire-Atlantique, France

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Compiègne, Oise, France

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Clermont-Ferrand, Puy-de-Dôme, France

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Le Mans, Sarthe, France

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Villejuif, Val-de-Marne, France

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Montpellier, , France

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Karlsruhe, Baden-Wurttemberg, Germany

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Krefeld, North Rhine-Westphalia, Germany

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Velbert, North Rhine-Westphalia, Germany

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Dresden, Saxony, Germany

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Kiel, Schleswig-Holstein, Germany

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Central, Hong Kong, Hong Kong

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Central, Hong Kong, Hong Kong

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Kowloon, Hong Kong, Hong Kong

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Hong Kong, , Hong Kong

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Hong Kong, , Hong Kong

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Pécs, Baranya, Hungary

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Kecskemét, Bács-Kiskun county, Hungary

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Debrecen, Hajdú-Bihar, Hungary

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Avellino, Campania, Italy

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Bologna, Emilia-Romagna, Italy

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Meldola, Emilia-Romagna, Italy

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Modena, Emilia-Romagna, Italy

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Reggio Emilia, Emilia-Romagna, Italy

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Udine, Friuli Venezia Giulia, Italy

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Rome, Lazio, Italy

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Rome, Lazio, Italy

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Milan, Lombardy, Italy

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Rozzano, Lombardy, Italy

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Alessandria, Piedmont, Italy

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Pavia, , Italy

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Sungai Petani, Kedah, Malaysia

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Kota Bharu, Kelantan, Malaysia

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Ipoh, Perak, Malaysia

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George Town, Pulau Pinang, Malaysia

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Putrajaya, Putramya, Malaysia

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Kuching, Sarawak, Malaysia

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Petaling Jaya, Selangor, Malaysia

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Kuala Lumpur, WP, Malaysia

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Zapopan, Jalisco, Mexico

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Monterrey, , Mexico

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Oaxaca City, , Mexico

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Sinaloa, , Mexico

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Amsterdam, North Holland, Netherlands

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Rotterdam, South Holland, Netherlands

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Skórzewo, Greater Poland Voivodeship, Poland

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Lublin, Lublin Voivodeship, Poland

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Lodz, Lódzkie, Poland

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Otwock, Masovian Voivodeship, Poland

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Brzozów, Podkarpackie Voivodeship, Poland

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Rzeszów, Podkarpackie Voivodeship, Poland

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Gdynia, Pomeranian Voivodeship, Poland

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Krakow, , Poland

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Wroclaw, , Poland

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Coimbra, Coimbra District, Portugal

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Lisbon, Lisbon District, Portugal

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Lisbon, Lisbon District, Portugal

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Matosinhos Municipality, Porto District, Portugal

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Porto, Porto District, Portugal

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Mayagüez, Puerto Rico, Puerto Rico

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Oradea, Bihor County, Romania

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Brasov, Brașov County, Romania

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Bucharest, București, Romania

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Cluj-Napoca, Cluj, Romania

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Craiova, Dolj, Romania

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Iași, Iaşi, Romania

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Timișoara, Timiș County, Romania

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Suwon, Gyeonggi-do, South Korea

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Busan, , South Korea

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Seoul, , South Korea

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Seoul, , South Korea

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Seoul, , South Korea

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Seoul, , South Korea

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Seoul, , South Korea

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Seoul, , South Korea

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Seoul, , South Korea

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Suwon, , South Korea

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Badajoz, Badajoz, Spain

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Girona, Girona, Spain

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León, León, Spain

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Lleida, Lleida, Spain

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Madrid, Madrid, Spain

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Pamplona, Navarre, Spain

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Seville, Sevilla, Spain

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Valencia, Valencia, Spain

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Alicante, , Spain

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Madrid, , Spain

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Santiago de Compostela, , Spain

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Changhua, , Taiwan

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Kaohsiung City, , Taiwan

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Taichung, , Taiwan

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Taichung, , Taiwan

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Tainan City, , Taiwan

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Taipei, , Taiwan

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Taipei, , Taiwan

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Taipei, , Taiwan

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Taipei, , Taiwan

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Bangkok, , Thailand

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Bangkok, , Thailand

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Bangkok, , Thailand

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Chiang Mai, , Thailand

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Samut Sakhon, , Thailand

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Songkhla, , Thailand

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Leicester, Leicestershire, United Kingdom

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Nottingham, Nottingham, United Kingdom

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Taunton, Somerset, United Kingdom

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Bodelwyddan, , United Kingdom

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London, , United Kingdom

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Countries

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United States Argentina Australia Belgium Brazil Bulgaria Canada Czechia France Germany Hong Kong Hungary Italy Malaysia Mexico Netherlands Poland Portugal Puerto Rico Romania South Korea Spain Taiwan Thailand United Kingdom

Central Contacts

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Olema Pharmaceuticals, Inc.

Role: CONTACT

415-651-7206

Related Links

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Other Identifiers

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OPERA-01

Identifier Type: OTHER

Identifier Source: secondary_id

OP-1250-301

Identifier Type: -

Identifier Source: org_study_id

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