A Phase II, Open-Label, Randomized, Parallel-Group Multicenter Trial Comparing Two Schedules of GW572016 as First-Line Monotherapy in Patients With Advanced or Metastatic Breast Cancer

Study start date: June 1, 2004

Inclusion criteria: * Histologically confirmed invasive breast cancer with incurable stage IIIB, IIIC with T4 lesion or stage IV disease at primary diagnosis or at relapse after curative intent surgery. * Eastern Cooperative Oncology Group (ECOG) performance status 0 or 1. * Documented amplification of ErbB2 by Fluorescence in situ hybridization (FISH) * Measurable disease by Response Evaluation Criteria In Solid Tumors (RECIST) * Adequate renal, hepatic and cardiac function Exclusion criteria: * Prior chemotherapy, immunotherapy, biologic therapy or anti-ErbB1/ErbB2 therapy other than adjuvant therapy. \[Prior neo-adjuvant or adjuvant therapy (including trastuzumab) will be allowed provided it was stopped at least 12 months before study entry. * Patients with active brain metastases * Patients with bilateral breast cancer, bone metastases as the only disease site or metastases to more than 30% of the hepatic parenchyma.