NCT06016738

Brief 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.

Trial Health

88
On Track

Trial Health Score

Automated assessment based on enrollment pace, timeline, and geographic reach

Strong global presence with extensive site network
Enrollment
510

participants targeted

Target at P50-P75 for phase_3 breast-cancer

Timeline
17mo left

Started Nov 2023

Geographic Reach
25 countries

231 active sites

Status
recruiting

Health score is calculated from publicly available data and should be used for screening purposes only.

Trial Relationships

Click on a node to explore related trials.

Study Timeline

Key milestones and dates

Study Progress64%
Nov 2023Sep 2027

First Submitted

Initial submission to the registry

August 17, 2023

Completed
13 days until next milestone

First Posted

Study publicly available on registry

August 30, 2023

Completed
3 months until next milestone

Study Start

First participant enrolled

November 16, 2023

Completed
2.6 years until next milestone

Primary Completion

Last participant's last visit for primary outcome

June 30, 2026

Expected
1.3 years until next milestone

Study Completion

Last participant's last visit for all outcomes

September 30, 2027

Last Updated

March 13, 2026

Status Verified

August 1, 2025

Enrollment Period

2.6 years

First QC Date

August 17, 2023

Last Update Submit

March 11, 2026

Conditions

Outcome Measures

Primary Outcomes (4)

  • Dose-Selection Part: Incidence of adverse events

    To evaluate the number of participants with adverse events

    From Date of Randomization up to 16 weeks

  • Dose-Selection Part: Incidence of dose reduction

    To evaluate the number of participants reducing the dose of palazestrant

    From Date of Randomization up to 16 weeks

  • Dose-Selection Part: Incidence of drug discontinuation

    To evaluate the number of participants discontinuing palazestrant

    From Date of Randomization up to 16 weeks

  • Trial: Progression-Free Survival (PFS)

    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.

    From Date of Randomization until Disease Progression or Death Due to Any Cause (estimated as up to 2 years)

Secondary Outcomes (1)

  • Trial: Overall Survival (OS)

    From Date of Randomization until Death Due to Any Cause (estimated as up to 4 years)

Study Arms (2)

Palazestrant (OP-1250)

EXPERIMENTAL

Participants will receive Palazestrant

Drug: Palazestrant

Standard of Care Endocrine Therapy

ACTIVE COMPARATOR

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

Drug: FulvestrantDrug: AnastrozoleDrug: LetrozoleDrug: Exemestane

Interventions

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

Standard of Care Endocrine Therapy

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

Standard of Care Endocrine Therapy

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

Standard of Care Endocrine Therapy

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

Standard of Care Endocrine Therapy

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.

Also known as: OP-1250
Palazestrant (OP-1250)

Eligibility Criteria

Age18 Years+
Sexall
Healthy VolunteersNo
Age GroupsAdult (18-64), Older Adult (65+)

You may qualify if:

  • 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.

You may not qualify if:

  • 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.

Contact the study team to confirm eligibility.

Sponsors & Collaborators

Study Sites (233)

Clinical Trial Site

Tucson, Arizona, 85719, United States

RECRUITING

Clinical Trial Site

Fountain Valley, California, 92708, United States

NOT YET RECRUITING

Clinical Trial Site

Glendale, California, 91204, United States

NOT YET RECRUITING

Clinical Trial Site

La Jolla, California, 92093, United States

COMPLETED

Clinical Trial Site

Los Alamitos, California, 90720, United States

RECRUITING

Clinical Trial Site

Los Angeles, California, 90027, United States

RECRUITING

Clinical Trial Site

Whittier, California, 90602, United States

RECRUITING

Clinical Trial Site

Aurora, Colorado, 80045, United States

RECRUITING

Clinical Trial Site

Denver, Colorado, 80218, United States

RECRUITING

Clinical Trial Site

Golden, Colorado, 80401, United States

RECRUITING

Clinical Trial Site

Grand Junction, Colorado, 81505, United States

ACTIVE NOT RECRUITING

Clinical Trial Site

Danbury, Connecticut, 06810, United States

RECRUITING

Clinical Trial Site

Newark, Delaware, 19713, United States

RECRUITING

Clinical Trials Site

Jacksonville, Florida, 32223, United States

WITHDRAWN

Clinical Trial Site

Margate, Florida, 33063, United States

RECRUITING

Clinical Trial Site

Orlando, Florida, 32804, United States

RECRUITING

Clinical Trial Site

Plantation, Florida, 33324, United States

RECRUITING

Clinical Trial Site

Tamarac, Florida, 33321, United States

RECRUITING

Clinical Trial Site

Atlanta, Georgia, 30322, United States

RECRUITING

Clinical Trial Site

Chicago, Illinois, 60616-2315, United States

RECRUITING

Clinical Trial Site

Chicago, Illinois, 60637, United States

RECRUITING

Clinical Trial Site

Urbana, Illinois, 61801, United States

RECRUITING

Clinical Trial Site

Baton Rouge, Louisiana, 70809, United States

WITHDRAWN

Clinical Trial Site

New Orleans, Louisiana, 70112, United States

RECRUITING

Clinical Trial Site

Baltimore, Maryland, 21201, United States

RECRUITING

Clinical Trial Site

Boston, Massachusetts, 02111, United States

RECRUITING

Clinical Trial Site

Detroit, Michigan, 48202, United States

RECRUITING

Clinical Trial Site

Saint Louis Park, Minnesota, 55426, United States

RECRUITING

Clinical Trial Site

Woodbury, Minnesota, 55125, United States

RECRUITING

Clinical Trial Site

Lincoln, Nebraska, 68516, United States

RECRUITING

Clinical Trial Site

Farmington, New Mexico, 87401, United States

RECRUITING

Clinical Trial Site

New York, New York, 10032, United States

RECRUITING

Clinical Trial Site

Port Jefferson Station, New York, 11776, United States

WITHDRAWN

Clinical Trial Site

Dayton, Ohio, 45415, United States

RECRUITING

Clinical Trial Site

Toledo, Ohio, 43623, United States

WITHDRAWN

Clinical Trial Site

Portland, Oregon, 97239, United States

RECRUITING

Clinical Trial Site

Sayre, Pennsylvania, 18840, United States

RECRUITING

Clinical Trial Site

Nashville, Tennessee, 37203, United States

RECRUITING

Clinical Trial Site

Nashville, Tennessee, 37208, United States

RECRUITING

Clinical Trial Site

Nashville, Tennessee, 37232, United States

RECRUITING

Clinical Trial Site

Dallas, Texas, 75246, United States

RECRUITING

Clinical Trial Site

Dallas, Texas, 75390, United States

RECRUITING

Clinical Trial Site

Houston, Texas, 77054, United States

RECRUITING

Clinical Trial Site

Webster, Texas, 77598, United States

RECRUITING

Clinical Trial Site

Ogden, Utah, 84405, United States

RECRUITING

Clinical Trial Site

Spokane, Washington, 99204, United States

WITHDRAWN

Clinical Trial Site

Spokane, Washington, 99208, United States

RECRUITING

Clinical Trial Site

Bahía Blanca, Buenos Aires, B8000HXM, Argentina

ACTIVE NOT RECRUITING

Clinical Trial Site

Mar del Plata, Buenos Aires, B7600FZN, Argentina

ACTIVE NOT RECRUITING

Clinical Trial Site

Mar del Plata, Buenos Aires, Argentina

ACTIVE NOT RECRUITING

Clinical Trial Site

Córdoba, Córdoba Province, X5000HHW, Argentina

ACTIVE NOT RECRUITING

Clinical Trial Site

Córdoba, Córdoba Province, X5008HHW, Argentina

ACTIVE NOT RECRUITING

Clinical Trial Site

San Salvador de Jujuy, Jujuy Province, 4600, Argentina

ACTIVE NOT RECRUITING

Clinical Trial Site

La Rioja, La Rioja Province, 5300, Argentina

ACTIVE NOT RECRUITING

Clinical Trial Site

Viedma, Río Negro Province, R8500ACE, Argentina

ACTIVE NOT RECRUITING

Clinical Trial Site

Rosario, Santa Fe Province, S2013DTC, Argentina

ACTIVE NOT RECRUITING

Clinical Trial Site

Rosario, Santa Fe Province, S2013KDS, Argentina

ACTIVE NOT RECRUITING

Clinical Trial Site

San Miguel de Tucumán, Tucumán Province, 4000, Argentina

ACTIVE NOT RECRUITING

Clinical Trial Site

Buenos Aires, C14626ABP, Argentina

ACTIVE NOT RECRUITING

Clinical Trial Site

Gosford, New South Wales, 2250, Australia

RECRUITING

Clinical Trial Site

Westmead, New South Wales, 2145, Australia

RECRUITING

Clinical Trial Site

Adelaide, South Australia, 5000, Australia

RECRUITING

Clinical Trial Site

Ballarat Central, Victoria, 3355, Australia

RECRUITING

Clinical Trial Site

Clayton, Victoria, 3168, Australia

RECRUITING

Clinical Trial Site

Shepparton, Victoria, 3630, Australia

RECRUITING

Clinical Trial Site

Nedlands, Western Australia, 6009, Australia

RECRUITING

Clinical Trial Site

Wels, 4600, Austria

RECRUITING

Clinical Trial Site

Wiener Neustadt, 2700, Austria

RECRUITING

Clinical Trial Site

Edegem, Antwerpen, 2650, Belgium

RECRUITING

Clinical Trial Site

Wilrijk, Antwerpen, 2610, Belgium

RECRUITING

Clinical Trial Site

Woluwe-Saint-Lambert, Brussels Capital, 1200, Belgium

RECRUITING

Clinical Trial Site

Charleroi, Hainaut, 6060, Belgium

RECRUITING

Clinical Trial Site

Leuven, Vlaams Brabant, Belgium

WITHDRAWN

Clinical Trial Site

Salvador, Estado de Bahia, 41253-190, Brazil

RECRUITING

Clinical Trial Site

Brasília, Federal District, 70.390-140, Brazil

RECRUITING

Clinical Trial Site

São Luís, Maranhão, 65.060-645, Brazil

RECRUITING

Clinical Trial Site

Belo Horizonte, Minas Gerais, 30150-221, Brazil

RECRUITING

Clinical Trial Site

Curitiba, Paraná, 81520-060, Brazil

RECRUITING

Clinical Trial Site

Recife, Pernambuco, 50070-480, Brazil

RECRUITING

Clinical Trial Site

Porto Alegre, Rio Grande do Sul, 90035-903, Brazil

RECRUITING

Clinical Trial Site

Porto Alegre, Rio Grande do Sul, 90050-170, Brazil

RECRUITING

Clinical Trial Site

Porto Alegre, Rio Grande do Sul, 91350-200, Brazil

RECRUITING

Clinical Trial Site

Itajaí, Santa Catarina, 88301-220, Brazil

RECRUITING

Clinical Trial Site

Jaú, São Paulo, 17210-080, Brazil

RECRUITING

Clinical Trial Site

Sorocaba, São Paulo, 18052-775, Brazil

RECRUITING

Clinical Trial Site

Porto Alegre, 90470-340, Brazil

NOT YET RECRUITING

Clinical Trial Site

Rio de Janeiro, 22281-100, Brazil

RECRUITING

Clinical Trial Site

Panagyurishte, Pazardzhik, 4500, Bulgaria

RECRUITING

Clinical Trial Site

Sofia, Sofia-Grad, 1407, Bulgaria

RECRUITING

Clinical Trial Site

Vratsa, Vratsa, 3000, Bulgaria

WITHDRAWN

Clinical Trial Site

Calgary, Alberta, T2N 5G2, Canada

RECRUITING

Clinical Trial Site

London, Ontario, N6A 5W9, Canada

RECRUITING

Clinical Trial Site

Toronto, Ontario, M5G 1X5, Canada

RECRUITING

Clinical Trial Site

Montreal, Quebec, H4A 3J1, Canada

RECRUITING

Clinical Trial Site

Hradec Králové, Královéhradecký kraj, 500 12, Czechia

WITHDRAWN

Clinical Trial Site

Nový Jičín, Moravskoslezský kraj, 741 01, Czechia

RECRUITING

Clinical Trial Site

Olomouc, Olomoucký kraj, 779 00, Czechia

RECRUITING

Clinical Trial Site

Brno, 625 00, Czechia

RECRUITING

Clinical Trial Site

Prague, 140 59, Czechia

RECRUITING

Clinical Trial Site

Bourg-en-Bresse, Ain, 01000, France

RECRUITING

Clinical Trial Site

Besançon, Doubs, 25030, France

RECRUITING

Clinical Trial Site

Nantes, Loire-Atlantique, 44277, France

RECRUITING

Clinical Trial Site

Nantes, Loire-Atlantique, 44805, France

RECRUITING

Clinical Trial Site

Compiègne, Oise, 60200, France

RECRUITING

Clinical Trial Site

Clermont-Ferrand, Puy-de-Dôme, 63011, France

RECRUITING

Clinical Trial Site

Le Mans, Sarthe, 7200, France

RECRUITING

Clinical Trial Site

Villejuif, Val-de-Marne, 94805, France

RECRUITING

Clinical Trial Site

Caen, 14000, France

RECRUITING

Clinical Trial Site

Montpellier, 34070, France

RECRUITING

Clinical Trial Site

Paris, 75014, France

NOT YET RECRUITING

Clinical Trial Site

Karlsruhe, Baden-Wurttemberg, 76135, Germany

RECRUITING

Clinical Trial Site

Krefeld, North Rhine-Westphalia, 47805, Germany

RECRUITING

Clinical Trial Site

Velbert, North Rhine-Westphalia, 42551, Germany

RECRUITING

Clinical Trial Site

Dresden, Saxony, 01307, Germany

RECRUITING

Clinical Trial Site

Kiel, Schleswig-Holstein, 24105, Germany

RECRUITING

Clinical Trial Site

Central, Hong Kong, 100176, Hong Kong

WITHDRAWN

Clinical Trial Site

Hong Kong, Hong Kong, 999077, Hong Kong

RECRUITING

Clinical Trial Site

Kowloon, Hong Kong, 999077, Hong Kong

RECRUITING

Clinical Trial Site

Hong Kong, 999077, Hong Kong

RECRUITING

Clinical Trials Site

Hong Kong, 999077, Hong Kong

RECRUITING

Clinical Trial Site

Pécs, Baranya, 7624, Hungary

RECRUITING

Clinical Trial Site

Kecskemét, Bács-Kiskun county, 6000, Hungary

RECRUITING

Clinical Trial Site

Debrecen, Hajdú-Bihar, 4032, Hungary

RECRUITING

Clinical Trial Site

Avellino, Campania, 83100, Italy

RECRUITING

Clinical Trial Site

Bologna, Emilia-Romagna, 40138, Italy

RECRUITING

Clinical Trial Site

Meldola, Emilia-Romagna, 47014, Italy

RECRUITING

Clinical Trial Site

Modena, Emilia-Romagna, 41124, Italy

RECRUITING

Clinical Trial Site

Reggio Emilia, Emilia-Romagna, 42100, Italy

RECRUITING

Clinical Trial Site

Udine, Friuli Venezia Giulia, 33100, Italy

WITHDRAWN

Clinical Trial Site

Rome, Lazio, 00144, Italy

RECRUITING

Clinical Trial Site

Rome, Lazio, 00168, Italy

RECRUITING

Clinical Trial Site

Milan, Lombardy, 20141, Italy

RECRUITING

Clinical Trial Site

Rozzano, Lombardy, 20089, Italy

RECRUITING

Clinical Trial Site

Piacenza, Piacenza, 29121, Italy

NOT YET RECRUITING

Clinical Trial Site

Alessandria, Piedmont, 15121, Italy

RECRUITING

Clinical Trial Site

Aviano, Pordenone, 33081, Italy

RECRUITING

Clinical Trial Site

Ancona, 60126, Italy

NOT YET RECRUITING

Clinical Trial Site

Genova, 16132, Italy

RECRUITING

Clinical Trial Site

Naples, 80131, Italy

NOT YET RECRUITING

Clinical Trial Site

Padua, 35128, Italy

RECRUITING

Clinical Trial Site

Pavia, 27100, Italy

RECRUITING

Clinical Trials Site

Sungai Petani, Kedah, 8000, Malaysia

RECRUITING

Clinical Trial Site

Kota Bharu, Kelantan, 16150, Malaysia

RECRUITING

Clinical Trial Site

Ipoh, Perak, 30450, Malaysia

RECRUITING

Clinical Trial Site

George Town, Pulau Pinang, 10450, Malaysia

RECRUITING

Clinical Trial Site

Putrajaya, Putramya, 62250, Malaysia

RECRUITING

Clinical Trial Site

Kuching, Sarawak, 93586, Malaysia

RECRUITING

Clinical Trial Site

Petaling Jaya, Selangor, 46050, Malaysia

RECRUITING

Clinical Trial Site

Kuala Lumpur, WP, 59100, Malaysia

RECRUITING

Clinical Trial Site

Guadalajara, Jalisco, 44670, Mexico

RECRUITING

Clinical Trial Site

Mexico City, Mexico City, 06760, Mexico

NOT YET RECRUITING

Clinical Trial Site

Puebla City, Puebla, 72530, Mexico

WITHDRAWN

Clinical Trial Site

San Luis Potosí City, San Luis Potosí, 78209, Mexico

RECRUITING

Clinical Trial Site

Monterrey, 64460, Mexico

RECRUITING

Clinical Trial Site

Oaxaca City, 68020, Mexico

RECRUITING

Clinical Trial Site

Sinaloa, 80020, Mexico

RECRUITING

Clinical Trial Site

Amsterdam, North Holland, 1081 HV, Netherlands

RECRUITING

Clinical Trial Site

Rotterdam, South Holland, 3083 AN, Netherlands

RECRUITING

Clinical Trial Site

Lublin, Lublin Voivodeship, 20-090, Poland

RECRUITING

Clinical Trial Site

Lodz, Lódzkie, 93-513, Poland

RECRUITING

Clinical Trial Site

Otwock, Masovian Voivodeship, 05-400, Poland

RECRUITING

Clinical Trial Site

Brzozów, Podkarpackie Voivodeship, 36-200, Poland

RECRUITING

Clinical Trial Site

Rzeszów, Podkarpackie Voivodeship, 35-021, Poland

RECRUITING

Clinical Trial Site

Gdynia, Pomeranian Voivodeship, 81-519, Poland

RECRUITING

Clinical Trial Site

Gdansk, 80-214, Poland

NOT YET RECRUITING

Clinical Trial Site

Krakow, 31-115, Poland

RECRUITING

Clinical Trial Site

Krakow, 31-501, Poland

RECRUITING

Clinical Trial Site

Poznan, 60-192, Poland

RECRUITING

Clinical Trial Site

Wroclaw, 50-450, Poland

WITHDRAWN

Clinical Trial Site

Coimbra, Coimbra District, 3000-075, Portugal

RECRUITING

Clinical Trial Site

Lisbon, Lisbon District, 1099-023, Portugal

RECRUITING

Clinical Trial Site

Lisbon, Lisbon District, 1500-458, Portugal

RECRUITING

Clinical Trial Site

Porto, Porto District, 4200-072, Portugal

RECRUITING

Clinical Trial Site

Senhora da Hora, Porto District, 4464-513, Portugal

RECRUITING

Clinical Trial Site

Mayagüez, Puerto Rico, 00682-6391, Puerto Rico

RECRUITING

Clinical Trial Site

Oradea, Bihor County, 410469, Romania

RECRUITING

Clinical Trial Site

Brasov, Brașov County, 500152, Romania

RECRUITING

Clinical Trial Site

Bucharest, București, 014146, Romania

RECRUITING

Clinical Trial Site

Cluj-Napoca, Cluj, 400015, Romania

RECRUITING

Clinical Trial Site

Cluj-Napoca, Cluj, 400132, Romania

NOT YET RECRUITING

Clinical Trial Site

Craiova, Dolj, 200542, Romania

RECRUITING

Clinical Trial Site

Iași, Iaşi, 700106, Romania

RECRUITING

Clinical Trial Site

Timișoara, Timiș County, 300239, Romania

RECRUITING

Clinical Trial Site

Bucharest, 030171, Romania

NOT YET RECRUITING

Clinical Trial Site

Iași, 700451, Romania

NOT YET RECRUITING

Clinical Trial Site

Suwon, Gyeonggi-do, 16247, South Korea

RECRUITING

Clinical Trial Site

Busan, 49201, South Korea

RECRUITING

Clinical Trial Site

Seoul, 02841, South Korea

RECRUITING

Clinical Trial Site

Seoul, 03080, South Korea

RECRUITING

Clinical Trial Site

Seoul, 03722, South Korea

RECRUITING

Clinical Trial Site

Seoul, 05505, South Korea

RECRUITING

Clinical Trial Site

Seoul, 06273, South Korea

RECRUITING

Clinical Trial Site

Seoul, 06591, South Korea

RECRUITING

Clinical Trial Site

Seoul, 08308, South Korea

RECRUITING

Clinical Trial Site

Suwon, 16499, South Korea

RECRUITING

Clinical Trial Site

Badajoz, Badajoz, 06080, Spain

RECRUITING

Clinical Trial Site

Badalona, Barcelona, 08916, Spain

NOT YET RECRUITING

Clinical Trial Site

Manresa, Barcelona, 08243, Spain

NOT YET RECRUITING

Clinical Trial Site

Girona, Girona, 17007, Spain

RECRUITING

Clinical Trial Site

León, León, 24071, Spain

RECRUITING

Clinical Trial Site

Lleida, Lleida, 25198, Spain

RECRUITING

Clinical Trial Site

Madrid, Madrid, 28050, Spain

RECRUITING

Clinical Trial Site

Pamplona, Navarre, 31008, Spain

RECRUITING

Clinical Trial Site

Seville, Sevilla, 41009, Spain

RECRUITING

Clinical Trial Site

Reus, Tarragona, 43204, Spain

NOT YET RECRUITING

Clinical Trial Site

Valencia, Valencia, 46010, Spain

RECRUITING

Clinical Trial Site

Alicante, 03010, Spain

RECRUITING

Clinical Trial Site

Barcelona, 08023, Spain

NOT YET RECRUITING

Clinical Trial Site

Fuenlabrada, 28942, Spain

RECRUITING

Clinical Trial Site

Madrid, 28033, Spain

RECRUITING

Clinical Trial Site

Murcia, 30120, Spain

NOT YET RECRUITING

Clinical Trial site

Santa Cruz de Tenerife, 38320, Spain

RECRUITING

Clinical Trial Site

Santiago de Compostela, 15706, Spain

RECRUITING

Clinical Trial Site

Changhua, 500, Taiwan

RECRUITING

Clinical Trial Site

Kaohsiung City, 80756, Taiwan

RECRUITING

Clinical Trial Site

Taichung, 40447, Taiwan

RECRUITING

Clinical Trial Site

Taichung, 433, Taiwan

RECRUITING

Clinical Trial Site

Tainan, 736, Taiwan

RECRUITING

Clinical Trial Site

Taipei, 100, Taiwan

RECRUITING

Clinical Trial Site

Taipei, 111, Taiwan

RECRUITING

Clinical Trial Site

Taipei, 11217, Taiwan

RECRUITING

Clinical Trial Site

Taipei, 114, Taiwan

RECRUITING

Clinical Trial Site

Bangkok, 10300, Thailand

RECRUITING

Clinical Trial Site

Bangkok, 10330, Thailand

RECRUITING

Clinical Trial Site

Bangkok, 10700, Thailand

RECRUITING

Clinical Trial Site

Chiang Mai, 50180, Thailand

RECRUITING

Clinical Trial Site

Samut Sakhon, 74120, Thailand

RECRUITING

Clinical Trial Site

Songkhla, 90110, Thailand

RECRUITING

Clinical Trial Site

Leicester, Leicestershire, LE1 5WW, United Kingdom

RECRUITING

Clinical Trial Site

Nottingham, Nottingham, NG5 1PB, United Kingdom

RECRUITING

Clinical Trial Site

Taunton, Somerset, TA1 5DA, United Kingdom

RECRUITING

Clinical Trial Site

Bodelwyddan, LL18 5UJ, United Kingdom

RECRUITING

Clinical Trial Site

London, EC1A 7BE, United Kingdom

RECRUITING

Related Publications (1)

  • Pistilli B, Bellet Ezquerra M, Del Mastro L, Sohn J, Schmid P, Meisel J, Chan A, Zheng L, de Kermadec E, McArthur H. OPERA-01: a phase III study of palazestrant for ER+, HER2- advanced breast cancer after CDK4/6 inhibitor therapy. Future Oncol. 2026 Jan;22(2):157-166. doi: 10.1080/14796694.2025.2608863. Epub 2025 Dec 29.

Related Links

MeSH Terms

Conditions

Breast Neoplasms

Interventions

FulvestrantAnastrozoleLetrozoleexemestane

Condition Hierarchy (Ancestors)

Neoplasms by SiteNeoplasmsBreast DiseasesSkin DiseasesSkin and Connective Tissue Diseases

Intervention Hierarchy (Ancestors)

EstradiolEstrenesEstranesSteroidsFused-Ring CompoundsPolycyclic CompoundsEstradiol CongenersGonadal Steroid HormonesGonadal HormonesHormonesHormones, Hormone Substitutes, and Hormone AntagonistsNitrilesOrganic ChemicalsTriazolesAzolesHeterocyclic Compounds, 1-RingHeterocyclic Compounds

Study Officials

  • Medical Director, MD

    Olema Pharmaceuticals, Inc.

    STUDY DIRECTOR

Central Study Contacts

Olema Pharmaceuticals, Inc.

CONTACT

Study Design

Study Type
interventional
Phase
phase 3
Allocation
RANDOMIZED
Masking
NONE
Purpose
TREATMENT
Intervention Model
PARALLEL
Sponsor Type
INDUSTRY
Responsible Party
SPONSOR

Study Record Dates

First Submitted

August 17, 2023

First Posted

August 30, 2023

Study Start

November 16, 2023

Primary Completion (Estimated)

June 30, 2026

Study Completion (Estimated)

September 30, 2027

Last Updated

March 13, 2026

Record last verified: 2025-08

Data Sharing

IPD Sharing
Will not share

Locations