Detecting Resistance to Endocrine Therapy in Metastatic Lobular Breast Cancer Using Minimally Invasive Biomarkers

What this Trial Is About

Researchers are studying patients with estrogen receptorprogesterone receptor positive ERPR metastatic lobular breast cancer who are starting new endocrine therapy. The study aims to identify biomarkers that show how the cancer responds to this treatment using imaging and blood tests. This Phase 2 study involves patients with advanced or metastatic lobular breast cancer and focuses on how estrogen signaling changes during therapy. Participants will receive an investigational imaging drug called 18F-fluorofuranylnorprogesterone FFNP through a slow intravenous infusion, followed by PETCT scans at the start and after 4 weeks of endocrine therapy. Blood samples will also be taken at these time points to analyze circulating tumor cells and DNA. The study tracks changes in estrogen signaling and correlates these with clinical response and progression-free survival over six months. During the study, participants will have PETCT scans and blood draws at baseline and four weeks after starting treatment. Researchers will monitor imaging results and blood biomarkers to measure response to therapy. They will also observe any adverse events related to the imaging drug infusion. The total observation period for progression-free survival is up to six months, and participants must comply with all study procedures and be available throughout the study duration.

Biomarkers to Detect Endocrine Therapy Resistance