New hope for advanced breast cancer: OP-1250 faces off against standard care

NCT ID NCT06016738

Disease control Sponsor: Olema Pharmaceuticals, Inc. Source: ClinicalTrials.gov ↗

First seen Jun 27, 2026 · Last updated Aug 14, 2026 · Updated 2 times

Summary

This study tests a new drug called OP-1250 (palazestrant) against the usual treatments (fulvestrant or an aromatase inhibitor) in people with a certain type of advanced breast cancer (ER+, HER2-). The goal is to see if OP-1250 can slow cancer growth better than standard care. The study includes 510 adults whose cancer has worsened after previous hormone therapy and a CDK4/6 inhibitor.

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Study facts

What this study's own registry entry says, in plain language.

Phase

Phase 3

Large-scale testing in a bigger group. Usually the last step before a treatment can be approved.

Participants

About 510 people

The number the study aims to enrol. It can still change while the study runs.

Started

Nov 2023

Expected to finish

Feb 2028

An estimate. End dates often move.

Lead sponsor

A company

The lead sponsor is a pharmaceutical, biotech, or medical-device company.

Who can take part

This study's own entry requirements. Only the study team can say for certain whether you qualify.

Ages

18 years and older

Sex

Anyone

Healthy volunteers

Not accepted

This study is not open to healthy volunteers. The entry requirements below say who it is open to.

Show the full entry requirements

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

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.

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Conditions

The condition(s) this trial relates to.

breast cancer breast neoplasm estrogen-receptor positive breast cancer Her2-receptor negative breast cancer hormone receptor-positive breast cancer

As listed by the trial registrant

The condition terms exactly as the trial's registrant entered them.

Advanced breast cancer Breast cancer ER-positive breast cancer HER2-negative breast carcinoma Metastatic breast cancer

Contacts and locations

Locations

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Tucson, Arizona, 85719, United States
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Fountain Valley, California, 92708, United States
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Glendale, California, 91204, United States
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La Jolla, California, 92093, United States
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Los Alamitos, California, 90720, United States
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Los Angeles, California, 90027, United States
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Whittier, California, 90602, United States
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Aurora, Colorado, 80045, United States
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Denver, Colorado, 80218, United States
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Golden, Colorado, 80401, United States
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Grand Junction, Colorado, 81505, United States
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Danbury, Connecticut, 06810, United States
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Newark, Delaware, 19713, United States
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Margate, Florida, 33063, United States
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Orlando, Florida, 32804, United States
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Plantation, Florida, 33324, United States
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Tamarac, Florida, 33321, United States
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Atlanta, Georgia, 30322, United States
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Chicago, Illinois, 60616-2315, United States
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Chicago, Illinois, 60637, United States
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Urbana, Illinois, 61801, United States
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Baton Rouge, Louisiana, 70809, United States
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New Orleans, Louisiana, 70112, United States
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Baltimore, Maryland, 21201, United States
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Boston, Massachusetts, 02111, United States
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Detroit, Michigan, 48202, United States
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Saint Louis Park, Minnesota, 55426, United States
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Woodbury, Minnesota, 55125, United States
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Lincoln, Nebraska, 68516, United States
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Farmington, New Mexico, 87401, United States
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New York, New York, 10032, United States
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Port Jefferson Station, New York, 11776, United States
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Dayton, Ohio, 45415, United States
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Toledo, Ohio, 43623, United States
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Portland, Oregon, 97239, United States
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Sayre, Pennsylvania, 18840, United States
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Nashville, Tennessee, 37203, United States
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Nashville, Tennessee, 37208, United States
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Nashville, Tennessee, 37232, United States
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Dallas, Texas, 75246, United States
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Dallas, Texas, 75390, United States
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Houston, Texas, 77054, United States
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Webster, Texas, 77598, United States
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Ogden, Utah, 84405, United States
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Spokane, Washington, 99204, United States
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Spokane, Washington, 99208, United States
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Bahía Blanca, Buenos Aires, B8000HXM, Argentina
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Mar del Plata, Buenos Aires, B7600FZN, Argentina
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Mar del Plata, Buenos Aires, Argentina
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Córdoba, Córdoba Province, X5000HHW, Argentina
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Córdoba, Córdoba Province, X5008HHW, Argentina
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San Salvador de Jujuy, Jujuy Province, 4600, Argentina
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La Rioja, La Rioja Province, 5300, Argentina
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Viedma, Río Negro Province, R8500ACE, Argentina
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Rosario, Santa Fe Province, S2013DTC, Argentina
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Rosario, Santa Fe Province, S2013KDS, Argentina
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San Miguel de Tucumán, Tucumán Province, 4000, Argentina
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Buenos Aires, C14626ABP, Argentina
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Gosford, New South Wales, 2250, Australia
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Westmead, New South Wales, 2145, Australia
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Adelaide, South Australia, 5000, Australia
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Ballarat Central, Victoria, 3355, Australia
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Clayton, Victoria, 3168, Australia
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Shepparton, Victoria, 3630, Australia
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Nedlands, Western Australia, 6009, Australia
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Wels, 4600, Austria
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Wiener Neustadt, 2700, Austria
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Edegem, Antwerpen, 2650, Belgium
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Wilrijk, Antwerpen, 2610, Belgium
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Woluwe-Saint-Lambert, Brussels Capital, 1200, Belgium
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Charleroi, Hainaut, 6060, Belgium
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Leuven, Vlaams Brabant, Belgium
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Salvador, Estado de Bahia, 41253-190, Brazil
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Brasília, Federal District, 70.390-140, Brazil
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São Luís, Maranhão, 65.060-645, Brazil
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Belo Horizonte, Minas Gerais, 30150-221, Brazil
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Curitiba, Paraná, 81520-060, Brazil
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Recife, Pernambuco, 50070-480, Brazil
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Porto Alegre, Rio Grande do Sul, 90035-903, Brazil
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Porto Alegre, Rio Grande do Sul, 90050-170, Brazil
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Porto Alegre, Rio Grande do Sul, 91350-200, Brazil
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Itajaí, Santa Catarina, 88301-220, Brazil
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Jaú, São Paulo, 17210-080, Brazil
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Sorocaba, São Paulo, 18052-775, Brazil
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Porto Alegre, 90470-340, Brazil
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Rio de Janeiro, 22281-100, Brazil
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Panagyurishte, Pazardzhik, 4500, Bulgaria
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Sofia, Sofia-Grad, 1407, Bulgaria
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Vratsa, Vratsa, 3000, Bulgaria
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Calgary, Alberta, T2N 5G2, Canada
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London, Ontario, N6A 5W9, Canada
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Toronto, Ontario, M5G 1X5, Canada
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Montreal, Quebec, H4A 3J1, Canada
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Hradec Králové, Hradec Králové Region, 500 12, Czechia
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Nový Jičín, Moravian-Silesian Region, 741 01, Czechia
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Olomouc, Olomouc Region, 779 00, Czechia
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Brno, 625 00, Czechia
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Prague, 140 59, Czechia
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Bourg-en-Bresse, Ain, 01000, France
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Besançon, Doubs, 25030, France
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Nantes, Loire-Atlantique, 44277, France
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Nantes, Loire-Atlantique, 44805, France
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Compiègne, Oise, 60200, France
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Clermont-Ferrand, Puy-de-Dôme, 63011, France
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Le Mans, Sarthe, 7200, France
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Villejuif, Val-de-Marne, 94805, France
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Caen, 14000, France
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Montpellier, 34070, France
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Paris, 75014, France
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Karlsruhe, Baden-Wurttemberg, 76135, Germany
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Krefeld, North Rhine-Westphalia, 47805, Germany
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Velbert, North Rhine-Westphalia, 42551, Germany
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Dresden, Saxony, 01307, Germany
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Kiel, Schleswig-Holstein, 24105, Germany
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Central, Hong Kong, 100176, Hong Kong
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Hong Kong, Hong Kong, 999077, Hong Kong
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Kowloon, Hong Kong, 999077, Hong Kong
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Hong Kong, 999077, Hong Kong
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Pécs, Baranya, 7624, Hungary
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Kecskemét, Bács-Kiskun county, 6000, Hungary
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Debrecen, Hajdú-Bihar, 4032, Hungary
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Avellino, Campania, 83100, Italy
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Bologna, Emilia-Romagna, 40138, Italy
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Meldola, Emilia-Romagna, 47014, Italy
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Modena, Emilia-Romagna, 41124, Italy
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Reggio Emilia, Emilia-Romagna, 42100, Italy
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Udine, Friuli Venezia Giulia, 33100, Italy
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Rome, Lazio, 00144, Italy
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Rome, Lazio, 00168, Italy
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Milan, Lombardy, 20141, Italy
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Rozzano, Lombardy, 20089, Italy
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Piacenza, Piacenza, 29121, Italy
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Alessandria, Piedmont, 15121, Italy
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Aviano, Pordenone, 33081, Italy
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Ancona, 60126, Italy
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Genova, 16132, Italy
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Naples, 80131, Italy
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Padova, 35128, Italy
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Pavia, 27100, Italy
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Kota Bharu, Kelantan, 16150, Malaysia
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Ipoh, Perak, 30450, Malaysia
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George Town, Pulau Pinang, 10450, Malaysia
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Putrajaya, Putramya, 62250, Malaysia
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Kuching, Sarawak, 93586, Malaysia
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Petaling Jaya, Selangor, 46050, Malaysia
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Kuala Lumpur, WP, 59100, Malaysia
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Guadalajara, Jalisco, 44670, Mexico
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Mexico City, Mexico City, 06760, Mexico
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Puebla City, Puebla, 72530, Mexico
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San Luis Potosí City, San Luis Potosí, 78209, Mexico
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Monterrey, 64460, Mexico
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Oaxaca City, 68020, Mexico
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Sinaloa, 80020, Mexico
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Amsterdam, North Holland, 1081 HV, Netherlands
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Rotterdam, South Holland, 3083 AN, Netherlands
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Lublin, Lublin Voivodeship, 20-090, Poland
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Lodz, Lódzkie, 93-513, Poland
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Otwock, Masovian Voivodeship, 05-400, Poland
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Brzozów, Podkarpackie Voivodeship, 36-200, Poland
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Rzeszów, Podkarpackie Voivodeship, 35-021, Poland
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Gdynia, Pomeranian Voivodeship, 81-519, Poland
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Gdansk, 80-214, Poland
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Krakow, 31-115, Poland
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Krakow, 31-501, Poland
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Poznan, 60-192, Poland
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Wroclaw, 50-450, Poland
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Coimbra, Coimbra District, 3000-075, Portugal
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Lisbon, Lisbon District, 1099-023, Portugal
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Lisbon, Lisbon District, 1500-458, Portugal
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Porto, Porto District, 4200-072, Portugal
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Senhora da Hora, Porto District, 4464-513, Portugal
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Mayagüez, Puerto Rico, 00682-6391, Puerto Rico
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Oradea, Bihor County, 410469, Romania
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Brasov, Brașov County, 500152, Romania
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Bucharest, Bucharest, 014146, Romania
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Cluj-Napoca, Cluj, 400015, Romania
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Cluj-Napoca, Cluj, 400132, Romania
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Craiova, Dolj, 200542, Romania
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Iași, Iaşi, 700106, Romania
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Timișoara, Timiș County, 300239, Romania
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Bucharest, 030171, Romania
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Iași, 700451, Romania
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Suwon, Gyeonggi-do, 16247, South Korea
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Busan, 49201, South Korea
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Seoul, 02841, South Korea
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Seoul, 03080, South Korea
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Seoul, 03722, South Korea
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Seoul, 05505, South Korea
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Seoul, 06273, South Korea
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Seoul, 06591, South Korea
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Seoul, 08308, South Korea
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Suwon, 16499, South Korea
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Badajoz, Badajoz, 06080, Spain
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Badalona, Barcelona, 08916, Spain
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Manresa, Barcelona, 08243, Spain
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Girona, Girona, 17007, Spain
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León, León, 24071, Spain
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Lleida, Lleida, 25198, Spain
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Madrid, Madrid, 28050, Spain
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Pamplona, Navarre, 31008, Spain
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Seville, Sevilla, 41009, Spain
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Reus, Tarragona, 43204, Spain
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Valencia, Valencia, 46010, Spain
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Alicante, 03010, Spain
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Barcelona, 08023, Spain
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Fuenlabrada, 28942, Spain
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Madrid, 28033, Spain
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Murcia, 30120, Spain
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Santiago de Compostela, 15706, Spain
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Changhua, 500, Taiwan
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Kaohsiung City, 80756, Taiwan
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Taichung, 40447, Taiwan
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Taichung, 433, Taiwan
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Tainan, 736, Taiwan
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Taipei, 100, Taiwan
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Taipei, 111, Taiwan
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Taipei, 11217, Taiwan
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Taipei, 114, Taiwan
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Bangkok, 10300, Thailand
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Bangkok, 10330, Thailand
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Bangkok, 10700, Thailand
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Chiang Mai, 50180, Thailand
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Samut Sakhon, 74120, Thailand
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Songkhla, 90110, Thailand
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Leicester, Leicestershire, LE1 5WW, United Kingdom
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Nottingham, Nottingham, NG5 1PB, United Kingdom
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Taunton, Somerset, TA1 5DA, United Kingdom
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Bodelwyddan, LL18 5UJ, United Kingdom
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London, EC1A 7BE, United Kingdom
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Santa Cruz de Tenerife, 38320, Spain
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Jacksonville, Florida, 32223, United States
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Hong Kong, 999077, Hong Kong
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Sungai Petani, Kedah, 8000, Malaysia

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