Levels of Circulating Tumor DNA as a Predictive Marker for Early Switch in Treatment for Patients With Metastatic (Stage IV) Breast Cancer

Study Summary

The majority of patients (pts) with breast cancer have hormone receptor positive (HR+) disease, and this holds true for pts with advanced breast cancer (ABC). Currently frontline therapy for pts with HR+ ABC is antihormonal therapy with an aromatase inhibitor or selective estrogen receptor degrader plus a CDK4/6i. The proposed trial is a randomized study to further evaluate the potential benefit of switching a frontline regimen at the time that a molecular signal, ctDNA, suggests progression prior to detection of clinical progression using standard methods. The purpose of this study is to determine whether switching treatment earlier in the disease process, based on molecular progression, will increase the amount of time that a patient's metastatic breast cancer is controlled compared to patients with metastatic breast cancer who receive treatment later based on diagnostic imaging results or other methods currently used in medical practice.

Primary Outcome

PFS1 is defined as the elapsed time in months from the date of randomization (at time a rise in ctDNA ratio \> 1 is detected prior to clinical progression) to the date of first clinical progression or death as determined by standard clinical methods or death in randomized participants.

Conditions Studied

Interventions

• DRUG AI+CDK4/6i
• DRUG SERD+CDK4/6i
• DRUG mTOR inhibitor + AI
• DRUG mTOR inhibitor + SERD
• DRUG mTOR inhibitor + Selective estrogen receptor modulator

Study Locations (1)