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) (ZEST)

  • End date
    Aug 28, 2029
  • participants needed
  • sponsor
Updated on 25 October 2022
growth factor
endocrine therapy
hormone therapy
epidermal growth factor
adjuvant chemotherapy
her2/neu-negative breast cancer


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. Participants who have completed definitive therapy at any time in the past are eligible for ctDNA monitoring and potential enrollment onto the trial.

Condition Neoplasms, Breast
Treatment Placebo, Niraparib
Clinical Study IdentifierNCT04915755
Last Modified on25 October 2022


Yes No Not Sure

Inclusion Criteria

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
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

Exclusion Criteria

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 received live vaccine within 30 days of planned start of study randomization
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
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
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
Participants have a known history of myelodysplastic syndrome (MDS) or acute myeloid leukemia (AML)
Participant is immunocompromised. Participants with splenectomy are allowed. Participants with known human immunodeficiency virus (HIV) are allowed if they meet protocol-defined criteria
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