Dataset from A Phase II Study of Lapatinib for Brain Metastases in Subjects With ErbB2-Positive Breast Cancer Following Trastuzumab-based Systemic Therapy and Cranial Radiotherapy

Determine how safe and effective lapatinib is when used to treat patients with ErbB2 overexpressing breast cancer that has spread to the brain and is still progressing there even after radiation treatment using WBRT (whole brain radiotherapy) or SRS (stereotactic radiosurgery) to the brain. Lapatinib is an oral drug that will be taken every day. Tests for safety and efficacy will be performed every 4 weeks or 8 weeks (depending on the test) during the course of the study.