Efficacy and Safety Comparison of Niraparib to Placebo in Participants With Human Epidermal Growth Factor 2 Negative (HER2-) Breast Cancer Susceptibility Gene Mutation (BRCAmut) or Triple-Negative Breast Cancer (TNBC) With Molecular Disease
ZEST
A Randomized Phase 3 Double-Blinded Study Comparing the Efficacy and Safety of Niraparib to Placebo in Participants With Either HER2-Negative BRCA-Mutated or Triple-Negative Breast Cancer With Molecular Disease Based on Presence of Circulating Tumor DNA After Definitive Therapy (ZEST)
2 other identifiers
interventional
40
26 countries
194
Brief Summary
This study will assess the efficacy and safety of Niraparib in participants with either tumor mutation in the BRCA gene (tBRCAmut) HER2- breast cancer (Independent of hormone receptor \[HR\] status, including HR positive \[+\] and TNBC) or tumor BRCA wild type (tBRCAwt) TNBC with molecular disease based on the presence of circulating tumor Deoxyribonucleic acid (ctDNA) following surgery or completion of adjuvant therapy.
Trial Health
Trial Health Score
Automated assessment based on enrollment pace, timeline, and geographic reach
participants targeted
Target at below P25 for phase_3
Started Jun 2021
Typical duration for phase_3
194 active sites
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
First Submitted
Initial submission to the registry
June 1, 2021
CompletedFirst Posted
Study publicly available on registry
June 7, 2021
CompletedStudy Start
First participant enrolled
June 28, 2021
CompletedPrimary Completion
Last participant's last visit for primary outcome
June 28, 2024
CompletedResults Posted
Study results publicly available
July 16, 2025
CompletedStudy Completion
Last participant's last visit for all outcomes
December 31, 2025
CompletedJuly 16, 2025
June 1, 2025
3 years
June 1, 2021
June 27, 2025
June 27, 2025
Conditions
Keywords
Outcome Measures
Primary Outcomes (8)
Number of Participants With Treatment Emergent Adverse Event (TEAEs), Serious Adverse Events (SAEs) and Adverse Events of Special Interest (AESIs)
An AE is any untoward medical occurrence in a participant or clinical investigation participant, temporally associated with the use of a medicinal product, whether or not considered related to the medicinal product. SAE is defined as any untoward medical occurrence that, at any dose resulted in death, is life threatening, required hospitalization or prolongation of existing hospitalization, resulted in disability/incapacity, is a congenital anomaly/birth defect, other situations and is associated with liver injury or impaired liver function. SAEs are subsets of AEs. TEAE is an event that emerged during treatment having been absent pretreatment or worsened relative to the pretreatment state. AESI is any AE (serious or nonserious) that is of scientific and medical concern specific to niraparib for which ongoing monitoring and rapid communication by the Investigator to the Sponsor is warranted. AEs were coded using the Medical Dictionary for Regulatory Activities (MedDRA) coding system.
Up to approximately 125 weeks
Number of Participants With TEAEs Leading to Death
An AE is any untoward medical occurrence in a participant or clinical investigation participant, temporally associated with the use of a medicinal product, whether or not considered related to the medicinal product. TEAE is an event that emerged during treatment having been absent pretreatment or worsened relative to the pretreatment state.Number of participants with TEAEs leading to death were reported.
Up to approximately 125 weeks
Number of Participants With TEAEs Leading to Dose Modifications and Discontinuation of Study Treatment
An AE is any untoward medical occurrence in a participant or clinical investigation participant, temporally associated with the use of a medicinal product, whether or not considered related to the medicinal product. TEAE is an event that emerged during treatment having been absent pretreatment or worsened relative to the pretreatment state. Number of participants with TEAEs leading to dose modifications (reduction and interruption/delay) and permanent discontinuation of study treatment were reported.
Up to approximately 125 weeks
Number of Participants With Eastern Cooperative Oncology Group (ECOG) Performance Status
Number of participants with ECOG Performance Status was reported and was measured on 6-point grade scale 0: Fully active, able to carry on all pre-disease performance without restriction. Grade 1: Restricted in physically strenuous activity but ambulatory \& able to carry out work of light or sedentary nature; Grade 2 - Ambulatory \& capable of all self-care but unable to carry out any work activities. Up and about more than (\>) 50% of waking hours; Grade 3 -Capable of only limited self-care, confined to bed or chair \> 50% of waking hours; Grade 4 -Completely disabled. Cannot carry on any self-care. Totally confined to bed or chair; Grade 5 -Dead. Data is presented as baseline grade, best case on-therapy, and worst-case on-therapy for the available participants.
Up to approximately 125 weeks
Number of Participants With Worst-Case Post-Baseline (WCPB) Hematology Results Relative to Baseline
Blood samples were collected for the analysis of hematology parameters. The summaries of worst-case change from baseline with respect to normal range was analyzed for only those laboratory tests that were not gradable by Common Terminology Criteria for Adverse Events (CTCAE) version (v) 5. The number of participants with decreases to low from baseline, changes to normal or no changes from baseline, and increases to high values have been presented. Baseline is defined as the latest non-missing pre-dose value, including those from unscheduled visits.
Up to approximately 125 weeks
Number of Participants With Worst-Case Post-Baseline (WCPB) Clinical Chemistry Results Relative to Baseline
Blood samples were collected for evaluation of clinical chemistry parameters. The summaries of worst case change from Baseline with respect to normal range have been presented for only those laboratory tests that are gradable by CTCAE v5.0. The number of participants with decreases to low, changes to normal or no changes from Baseline, and increases to high values have been presented. Baseline is defined as the latest non-missing pre-dose value, including those from unscheduled visits.
Up to approximately 125 weeks
Number of Participants With Worst-Case Post-Baseline (WCPB) Vital Signs Results Relative to Baseline
The abnormal vital sign ranges are: Pulse Rate (PR): Low \[\<60 beats per minute (bpm)\], Normal (60 bpm to 100 bpm), High (\>100 bpm); Temperature: Low (\<35 degree Celsius (°C)), Normal (35 C and 38 C), High (\>38 C); Systolic Blood Pressure (SBP): Low (\<90 millimeter of mercury (mmHg)), Normal (\>90 mmHg to \<120 mmHg), High (\>120 mmHg); Diastolic Blood Pressure (DBP): Low (\<60 mmHg), Normal (60 mmHg to 79 mmHg), High (\>80 mmHg). Participants were counted in the maximum worst case increase category that their value changes to (low, normal or high), unless there is no change in their category. Participants whose value category was unchanged (e.g., High to High), or whose value became normal, are recorded in the "To Normal or No Change" category.
Up to approximately 125 weeks
Number of Participants With Use of Concomitant Medications
Number of participants who used concomitant medications is presented.
Up to approximately 125 weeks
Study Arms (2)
Cohort1:Participants with tBRCAmut HER2-breast cancer(Independent of HR status,including HR+andTNBC)
EXPERIMENTALEligible participants will receive either Niraparib or Placebo.
Cohort 2: Participants with tBRCAwt TNBC
EXPERIMENTALEligible participants will receive either Niraparib or Placebo.
Interventions
Niraparib will be administered.
Matching placebo will be administered
Eligibility Criteria
You may qualify if:
- Stage I to III breast cancer with surgical resection of the primary tumor that is confirmed to be either: TNBC, irrespective of BRCA status or HR+/HER2- breast cancer with a known and documented deleterious or suspected deleterious tBRCA mutation.
- Estrogen receptor (ER) and/or progesterone receptor (PgR) negativity is defined as immunohistochemistry (IHC) nuclear staining less than (\<) 1 percentage (%), or by Allred scoring system where TNBC is defined to be 0 out of 8 or 2 out of 8, or staining in \<1 % of cancer cells.
- Completed prior standard therapy for curative intent.
- Participants with HR+ breast cancer must be on a stable regimen of endocrine therapy.
- Detectable ctDNA as measured by central testing.
- An archival tumor tissue specimen of the primary tumor sufficient in quality and quantity for ctDNA assay design and tBRCA and Homologous recombination deficiency (HRD) testing is required.
- An Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1.
You may not qualify if:
- Prior treatment with a Poly Adenosine-diphosphate Ribose Polymerase (PARP) inhibitor.
- Current treatment with a Cyclin-dependent kinase (CDK)4/6 inhibitor or endocrine therapy other than anastrozole, letrozole, exemestane, and tamoxifen with or without ovarian suppression.
- Participants have any sign of metastasis or local recurrence after comprehensive assessment conducted per protocol.
- Participants have shown no definitive response to preoperative chemotherapy by pathologic, radiographic or clinical evaluation, in cases where preoperative chemotherapy was administered.
- Participants have inadequately treated or controlled hypertension.
- Participants have received live vaccine within 30 days of planned start of study randomization.
- Participants have a second primary malignancy.
- Exceptions are the following: (a) Adequately treated non-melanoma skin cancer, curatively treated in situ cancer of the cervix, Ductal carcinoma in situ (DCIS) of the breast, Stage I Grade 1 endometrial carcinoma. (b) Other solid tumors and lymphomas (without bone marrow involvement) diagnosed \>=5 years prior to randomization and treated with no evidence of disease recurrence and for whom no more than 1 line of chemotherapy was applied.
- Participant is pregnant, breastfeeding, or expecting to conceive children while receiving study treatment and/or for up to 180 days after the last dose of study treatment (except France).
- Participant is immunocompromised. Participants with splenectomy are allowed. Participants with known human immunodeficiency virus (HIV) are allowed if they meet protocol-defined criteria.
- Participants have a known history of myelodysplastic syndrome (MDS) or acute myeloid leukemia (AML).
Contact the study team to confirm eligibility.
Sponsors & Collaborators
- GlaxoSmithKlinelead
Study Sites (198)
GSK Investigational Site
Burbank, California, 91505, United States
GSK Investigational Site
Duarte, California, 91010, United States
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Palo Alto, California, 94304, United States
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San Francisco, California, 94158, United States
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Aurora, Colorado, 80045, United States
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Highlands Ranch, Colorado, 80045, United States
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Chicago, Illinois, 60612, United States
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Skokie, Illinois, 60076, United States
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Ann Arbor, Michigan, 48109, United States
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Albuquerque, New Mexico, 87106, United States
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New York, New York, 10032, United States
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Fargo, North Dakota, 58122, United States
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Philadelphia, Pennsylvania, 19111, United States
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Pittsburgh, Pennsylvania, 15213, United States
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Sioux Falls, South Dakota, 57104, United States
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Austin, Texas, 78731, United States
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Dallas, Texas, 75231, United States
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Dallas, Texas, 75246, United States
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Fort Worth, Texas, 76104, United States
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Houston, Texas, 77024, United States
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San Antonio, Texas, 78240, United States
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Tyler, Texas, 75702, United States
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Norfolk, Virginia, 23502, United States
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Everett, Washington, 98201, United States
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Buenos Aires, C1017 AAS, Argentina
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Buenos Aires, C1125ABD, Argentina
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Buenos Aires, C1426ABP, Argentina
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Capital Federal, C1426ANZ, Argentina
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Cipoletti Rio Negro, R8324CVE, Argentina
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Ciudad Autonoma Buenos Aires, C1430EGF, Argentina
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Ciudad AutOnoma de Buenos Aire, C1015ABO, Argentina
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Ciudad Autonoma de Buenos Aire, C1426AGE, Argentina
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Ciudad de Buenos Aires, C1118AAT, Argentina
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Entre Ríos, 2822, Argentina
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Camperdown, New South Wales, 2050, Australia
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Macquarie Park, New South Wales, 2109, Australia
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North Sydney, New South Wales, 2060, Australia
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Feldkirch, A-6830, Austria
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Innsbruck, 6020, Austria
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Steyr, 4400, Austria
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Vienna, A-1090, Austria
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Brussels, 1070, Belgium
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Brussels, 1200, Belgium
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Charleroi, 6000, Belgium
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Ghent, 9000, Belgium
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Leuven, 3000, Belgium
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Belo Horizonte, 30130-100, Brazil
GSK Investigational Site
Florianópolis, 88034-000, Brazil
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Porto Alegre, 90020-090, Brazil
GSK Investigational Site
Porto Alegre, 90610000, Brazil
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Rio de Janeiro, 20560-120, Brazil
GSK Investigational Site
Rio Grande, 95070-560, Brazil
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Salvador, 40170-110, Brazil
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São Paulo, 01317000, Brazil
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São Paulo, 04312903, Brazil
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Vitória, 29043-260, Brazil
GSK Investigational Site
Calgary, Alberta, T2N 4N2, Canada
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Toronto, Ontario, M4N 3M5, Canada
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Toronto, Ontario, M5G 2M9, Canada
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Montreal, Quebec, H3T 1E2, Canada
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Québec, Quebec, G1S 4L8, Canada
GSK Investigational Site
Santiago, 7500653, Chile
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Santiago, 7500836, Chile
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Temuco, 5360000, Chile
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Helsinki, 00180, Finland
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Helsinki, HUS 00029, Finland
GSK Investigational Site
Turku, 20520, Finland
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Avignon, 84918, France
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Bordeaux, 33076, France
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Caen, 14000, France
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Dijon, 21000, France
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Marseille, 13915, France
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Montpellier, 34070, France
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Pierre-Bénite, 69495, France
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Rouen, 76000, France
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Saint-Cloud, 92210, France
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Berlin, 13125, Germany
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Cologne, 50935, Germany
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Erlangen, 91054, Germany
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Essen, 45136, Germany
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Mannheim, 68167, Germany
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München, 81377, Germany
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Ulm, 89075, Germany
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Debrecen, 4032, Hungary
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Dublin, 8, Ireland
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Dublin, 9, Ireland
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Beersheba, 84101, Israel
GSK Investigational Site
Haifa, 31096, Israel
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Jerusalem, 91031, Israel
GSK Investigational Site
Jerusalem, 91120, Israel
GSK Investigational Site
Petah Tikva, 49100, Israel
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Rehovot, 76100, Israel
GSK Investigational Site
Tel Aviv, 64239, Israel
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Ancona, 60126, Italy
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Ancona, 62100, Italy
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Bologna, 40138, Italy
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Brindisi, 72100, Italy
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Candiolo to, 10060, Italy
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Catania, 95122, Italy
GSK Investigational Site
Genova, 16132, Italy
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Meldola FC, 47014, Italy
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Milan, 20141, Italy
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Milan, 20157, Italy
GSK Investigational Site
Monza, 20900, Italy
GSK Investigational Site
Napoli, 80131, Italy
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Negrar Verona, 37024, Italy
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Padua, 35128, Italy
GSK Investigational Site
Aichi, 464-8681, Japan
GSK Investigational Site
Chiba, 277-8577, Japan
GSK Investigational Site
Ehime, 791-0280, Japan
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Fukuoka, 811-1395, Japan
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Hiroshima, 730-8518, Japan
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Hokkaido, 003-0804, Japan
GSK Investigational Site
Kagoshima, 892-0833, Japan
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Kanagawa, 216-8511, Japan
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Kanagawa, 241-8515, Japan
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Kanagawa, 259-1143, Japan
GSK Investigational Site
Okayama, 700-8558, Japan
GSK Investigational Site
Osaka, 541-8567, Japan
GSK Investigational Site
Osaka, 589-8511, Japan
GSK Investigational Site
Saitama, 350-1298, Japan
GSK Investigational Site
Saitama, 350-8550, Japan
GSK Investigational Site
Saitama, 362-0806, Japan
GSK Investigational Site
Tokyo, 104-0045, Japan
GSK Investigational Site
Tokyo, 113-8431, Japan
GSK Investigational Site
Tokyo, 135-8550, Japan
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Tokyo, 142-8666, Japan
GSK Investigational Site
León, 37178, Mexico
GSK Investigational Site
Mexico City, 04980, Mexico
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Monterrey, 64460, Mexico
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Monterrey, 66278, Mexico
GSK Investigational Site
Alkmaar, 1815 JD, Netherlands
GSK Investigational Site
Leeuwarden, 8934 AD, Netherlands
GSK Investigational Site
Maastricht, 6229 HX, Netherlands
GSK Investigational Site
Rotterdam, 3083 AN, Netherlands
GSK Investigational Site
The Hague, 2545 AA, Netherlands
GSK Investigational Site
Zwolle, 8025 AB, Netherlands
GSK Investigational Site
Drammen, N-3004, Norway
GSK Investigational Site
Stavanger, 4011, Norway
GSK Investigational Site
Katowice, 40-514, Poland
GSK Investigational Site
Krakow, 31-115, Poland
GSK Investigational Site
Krakow, 31-501, Poland
GSK Investigational Site
Olsztyn, 10-228, Poland
GSK Investigational Site
Poznan, 61-866, Poland
GSK Investigational Site
Rzeszów, 35-021, Poland
GSK Investigational Site
Siedlce, 08-110, Poland
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Szczecin, 70-707, Poland
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Warsaw, 02-781, Poland
GSK Investigational Site
Wroclaw, 53-413, Poland
GSK Investigational Site
Lisbon, 1649-035, Portugal
GSK Investigational Site
Loures, 2674-514, Portugal
GSK Investigational Site
Bucharest, 011171, Romania
GSK Investigational Site
Bucharest, 020142, Romania
GSK Investigational Site
Bucharest, 021389, Romania
GSK Investigational Site
Bucharest, 022343, Romania
GSK Investigational Site
Cluj-Napoca, 400015, Romania
GSK Investigational Site
Craiova, 200347, Romania
GSK Investigational Site
Otopeni, 075100, Romania
GSK Investigational Site
Timișoara, 300239, Romania
GSK Investigational Site
Chelyabinsk, 454048, Russia
GSK Investigational Site
Moscow, 111123, Russia
GSK Investigational Site
Moscow, 121309, Russia
GSK Investigational Site
Moscow, 143422, Russia
GSK Investigational Site
Omsk, 644013, Russia
GSK Investigational Site
Pushkin, 196603, Russia
GSK Investigational Site
Saint Petersburg, 197110, Russia
GSK Investigational Site
Saint Petersburg, 197758, Russia
GSK Investigational Site
StPetersburg, 197022, Russia
GSK Investigational Site
Cape Town, 7700, South Africa
GSK Investigational Site
Port Elizabeth, 6045, South Africa
GSK Investigational Site
Pretoria, 0041, South Africa
GSK Investigational Site
Barcelona, 08003, Spain
GSK Investigational Site
Barcelona, 08028, Spain
GSK Investigational Site
Barcelona, 08035, Spain
GSK Investigational Site
Cáceres, 10003, Spain
GSK Investigational Site
Córdoba, 14004, Spain
GSK Investigational Site
Granada, 18016, Spain
GSK Investigational Site
Madrid, 28034, Spain
GSK Investigational Site
Madrid, 28041, Spain
GSK Investigational Site
Madrid, 28046, Spain
GSK Investigational Site
Madrid, 28050, Spain
GSK Investigational Site
Málaga, 29010, Spain
GSK Investigational Site
Santiago de Compostela, 15706, Spain
GSK Investigational Site
Valencia, 46010, Spain
GSK Investigational Site
Zaragoza, 50009, Spain
GSK Investigational Site
Basel, 4031, Switzerland
GSK Investigational Site
Bath, BA1 3NG, United Kingdom
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Brighton, BN2 5BE, United Kingdom
GSK Investigational Site
Cardiff, CF14 2TL, United Kingdom
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Coventry, CV2 2DX, United Kingdom
GSK Investigational Site
Edinburgh, EH4 2XU, United Kingdom
GSK Investigational Site
Leeds, LS9 7TF, United Kingdom
GSK Investigational Site
London, SE1 9RT, United Kingdom
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London, SW3 6JJ, United Kingdom
GSK Investigational Site
Maidstone, ME16 9QQ, United Kingdom
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Manchester, M20 4BX, United Kingdom
GSK Investigational Site
Sutton, SM2 5PT, United Kingdom
GSK Investigational Site
Wigan, WN1 2NN, United Kingdom
MeSH Terms
Conditions
Interventions
Condition Hierarchy (Ancestors)
Results Point of Contact
- Title
- GSK Response Center
- Organization
- GlaxoSmithKline
Study Officials
- STUDY DIRECTOR
GSK Clinical Trials
GlaxoSmithKline
Publication Agreements
- PI is Sponsor Employee
- No
- Restriction Type
- OTHER
- Restrictive Agreement
- Yes
Study Design
- Study Type
- interventional
- Phase
- phase 3
- Allocation
- RANDOMIZED
- Masking
- DOUBLE
- Who Masked
- PARTICIPANT, INVESTIGATOR
- Masking Details
- This is a double-blind study
- Purpose
- TREATMENT
- Intervention Model
- PARALLEL
- Sponsor Type
- INDUSTRY
- Responsible Party
- SPONSOR
Study Record Dates
First Submitted
June 1, 2021
First Posted
June 7, 2021
Study Start
June 28, 2021
Primary Completion
June 28, 2024
Study Completion
December 31, 2025
Last Updated
July 16, 2025
Results First Posted
July 16, 2025
Record last verified: 2025-06
Data Sharing
- IPD Sharing
- Will share
- Shared Documents
- STUDY PROTOCOL, SAP, ICF, CSR
- Time Frame
- Anonymized IPD will be made available within 6 months of publication of primary, key secondary and safety results for studies in product with approved indication(s) or terminated asset(s) across all indications.
- Access Criteria
- Anonymized IPD is shared with researchers whose proposals are approved by an Independent Review Panel and after a Data Sharing Agreement is in place. Access is provided for an initial period of 12 months but an extension may be granted, when justified, for up to 6 months.
Qualified researchers may request access to anonymized individual patient-level data (IPD) and related study documents of the eligible studies via the Data Sharing Portal. Details on GSK's data sharing criteria can be found at: https://www.gsk.com/en-gb/innovation/trials/data-transparency/