Study of Signatera-Guided CDK46 Inhibitor and Hormone Therapy for Intermediate-Risk Early-Stage HRHER2- Breast Cancer

What this Trial Is About

Researchers are evaluating the use of circulating tumor DNA ctDNA testing to guide the timing of CDK46 inhibitor therapy in people with intermediate-risk, early-stage hormone receptor-positive HR, HER2-negative breast cancer. The study aims to determine if starting CDK46 inhibitor therapy based on ctDNA test results can maintain treatment effectiveness while reducing unnecessary therapy. Participants will be followed for up to nine years to monitor outcomes and quality of life. Participants will have ctDNA testing every three months using the Signatera Genome assay customized for each persons tumor. Those with positive ctDNA results will begin CDK46 inhibitor therapy ribociclib or abemaciclib along with hormone therapy. Participants with negative ctDNA results will continue hormone therapy alone and undergo ongoing ctDNA monitoring. If ctDNA positivity appears during follow-up, further staging will be done before starting CDK46 inhibitors. Treatment continues until disease progression, unacceptable side effects, or study completion. During the study, participants will have regular blood draws for ctDNA testing, hormone therapy, and imaging as needed. Researchers will track invasive disease-free survival for up to nine years after surgery. Outcomes at four years will be compared to a previous trial to assess if ctDNA-guided treatment timing is effective. Participants will also complete quality-of-life assessments and be monitored for safety throughout the study.

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