Using ctDNA Blood Test to Screen for Cancer DNA after Treatment for Early-Stage TNBC and/or an Inherited or Tumor BRCA Mutation; Followed by Study Comparing Niraparib with Placebo for People with Cancer DNA found in their Blood (ZEST) identifier:
NCT04915755 (

Early-stage TNBC or early-stage breast cancer with a BRCA mutation

Study Contact Information:

Contact: US GSK Clinical Trials Call Center at: 877-379-3718 or by email at: [email protected]  

About the Study

The ZEST study has two parts, a screening portion that will look for evidence of cancer cell DNA in the bloodstream, and an intervention portion that is open to people who test positive for cancer cell DNA in their bloodstream. 

ZEST will enroll people with early-stage triple negative breast cancer or people with an inherited or acquired BRCA1 or BRCA2 mutation who have completed treatment (or are still in treatment with hormone therapy) for monitoring using a blood test known as circulating tumor DNA (ctDNA). Individuals who test positive for ctDNA will be able to participate in a randomized study to receive the PARP inhibitor, niraparib or a placebo and undergo close monitoring with imaging (CT scans). The study will look at the safety and efficacy of niraparib plus monitoring compared with placebo plus monitoring for people who test positive for cancer cells in their blood but who have no evidence of cancer recurrence.

Currently, monitoring for circulating tumor DNA in people who have completed treatment for early-stage breast cancer is not standard-of-care. For this reason there is currently no standard-of-care treatment recommendations for people who test positive for circulating tumor DNA in the absence of other signs of recurrence.  Note: This study is no longer enrolling. 

This Study is Open To:

NOTE: This study is closed.

This Study is Not Open To:

NOTE: This study is closed.


FORCE is a national nonprofit organization, established in 1999. Our mission is to improve the lives of individuals and families affected by adult hereditary cancers.