# 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

Source: https://onco.cc/trials/nct04915755/  
OnCo record `nct04915755` (Trial). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

A phase 3 trial of Niraparib in triple-negative breast cancer, run by GlaxoSmithKline, active and no longer recruiting.

## Summary

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 is a phase 3 interventional study registered as NCT04915755 by GlaxoSmithKline, with 40 participants enrolled, started 2021-06-28 and due to reach its primary completion in 2024-06-28. Interventions recorded: Niraparib and Placebo. Results have been posted on the registry.

## Fields

- Kind: Trial
- Status: active
- Last checked: 2026-09-22
- Also known as: ZEST
- Tags: pipeline; ctgov-ingest
- Registry id: NCT04915755
- Phase: 3
- Setting: 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)
- Sponsor: GlaxoSmithKline
- Enrolled: 40
- Outcomes: Number of Participants With TEAEs Leading to Death: Niraparib 0 participants vs Placebo 0 participants

## Notes

- ZEST (NCT04915755, GlaxoSmithKline): randomised double-blind phase 3 of niraparib versus placebo for HER2-negative BRCA-mutated or triple-negative breast cancer with ctDNA detected after definitive therapy; the registry records only 40 participants randomised (actual) against the design, primary completion June 2024 and results posted July 2025 as safety outcomes, because too few screened patients were ctDNA-positive and free of recurrence at detection, the same problem c-TRAK TN met in the UK. Twelve UK sites (Bath, Brighton, Cardiff, Coventry, Edinburgh, Leeds, London, Maidstone, Manchester, Sutton, Wigan) took part.

## Sources

- ClinicalTrials.gov NCT04915755: https://clinicaltrials.gov/study/NCT04915755

## Connected records

- cancers: [Early triple-negative breast cancer](https://onco.cc/cancers/tnbc-early/), [Triple-negative breast cancer (TNBC)](https://onco.cc/cancers/tnbc/)
- technologies: [MRD / molecular residual disease testing](https://onco.cc/technologies/mrd-testing/), [PARP inhibitors](https://onco.cc/technologies/parp-inhibitor/)
- drugs: [Niraparib](https://onco.cc/drugs/niraparib/)
- companies: [GSK](https://onco.cc/companies/gsk/)
- terms: [Circulating tumour DNA (ctDNA)](https://onco.cc/terms/ctdna/), [Germline BRCA mutation (gBRCA)](https://onco.cc/terms/gbrca-mutation/), [Residual disease after neoadjuvant therapy in triple-negative breast cancer: the decision point](https://onco.cc/terms/tnbc-residual-disease-decision/)
- trials: [BRE12-158 (Hoosier Oncology Group)](https://onco.cc/trials/bre12-158/), [c-TRAK TN](https://onco.cc/trials/c-trak-tn/), [OlympiA](https://onco.cc/trials/olympia/)

---
JSON: https://onco.cc/api/v1/entities/nct04915755.json