Study of Poziotinib in Participants With HER2-Positive Metastatic Breast Cancer

This is a phase 2, open-label, multicenter study to establish the dose regimen and evaluate the preliminary efficacy and the safety/tolerability of poziotinib in participants with HER2-positive metastatic breast cancer who have received at least two prior HER2-directed treatment regimens. Each treatment cycle will be 21 days in duration. During each 21-day cycle, participants who are eligible for participation will receive poziotinib orally once daily. All treated participants will be followed up until disease progression, death, intolerable adverse events or up to a maximum of 24 months whichever comes earlier.