A Phase II Single-arm Study of Palbociclib in Patients With HER2-positive Breast Cancer With Brain Metastases and Analysis of ctDNA in Patients With Active Brain Metastases

Ami N. Shah, Cesar A. Santa‐Maria, Dhruvika Mukhija, Nikita Shah, Anthony K. Kang, Priya Kumthekar, Kirsten B. Burdett, Shruti Chandra, Jenny C. Chang, Dean Tsarwhas, Jill Woodman, Borko Jovanovic, Lorenzo Gerratana, William J. Gradishar, Massimo Cristofanilli