Serena-6 / D8534C00001

Topic of Study: Breast Cancer

Sponsor: AstraZeneca

Principal Investigator: David Riseberg, M.D., 410-783-5858

Research Coordinator: Alexandra Cline, RN, 410-951-7956; Meeghan Bey, RN, 410-951-7908

Coordinated Through: Institutional Research

This is a Phase III, Double-blind, Randomized study to assess switching to AZD9833 (a Next Generation, Oral SERD) plus a CDK4/6 Inhibitor (Palbociclib or Abemaciclib) versus continuing an Aromatase Inhibitor (Letrozole or Anastrozole) plus CDK4/6 Inhibitor in patients with Hormone receptor positive (HR+), HER2 negative metastatic breast cancer with a detectable ESR1 Mutation without disease progression during first line treatment. - A ctDNA Guided Early Switch Study (Clinicaltrials.gov ID#: NCT04964934)