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

A Phase 2 Study of Poziotinib in Patients With HER2-Positive Metastatic Breast Cancer (MBC) Who Have Received Prior HER2 Regimens for MBC

The purpose of this study is to establish the dose regimen and evaluate the preliminary efficacy and the safety/tolerability of poziotinib in participants with human epidermal growth factor receptor 2 (HER2)-positive metastatic breast cancer who have received at least two prior HER2-directed treatment regimens.

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.

Inclusion Criteria:

1. Histopathologically confirmed primary breast cancer with metastatic lesions.
2. Confirmed HER2 overexpression or gene-amplified tumor
3. At least two prior HER2-directed therapy regimens for breast cancer, including trastuzumab and trastuzumab emtansine
4. Measurable disease per Response Evaluation Criteria for Solid Tumors version 1.1 (RECIST v1.1)
5. Participant is at least 18, and ≤90 years of age.
6. Adequate hematologic, hepatic, and renal function
7. Eastern Cooperative Oncology Group (ECOG) performance status <= 2

Exclusion Criteria:

1. Previous treatment with poziotinib prior to study participation
2. Brain metastases that are symptomatic or require therapy to control symptoms, as well as any history of radiation, surgery, or other therapy, including steroids, to control symptoms from brain metastases within 15 days of enrollment.
3. Anticancer chemotherapy, biologics, immunotherapy, cure-intent radiotherapy, or investigational treatment within 15 days, except for hormone therapy, palliative therapy, or supportive therapy.
4. History of congestive heart failure Class III/IV according to the New York Heart Association (NYHA) Functional Classification or serious cardiac arrhythmias requiring treatment.
5. Cardiac ejection fraction <50%
6. History of other malignancies within the last 5 years
7. Participant is pregnant or breast-feeding.
8. Unable to take drugs orally