OUTLINE: This is a randomized, open label, multicenter study. Patients are randomized to one of two treatment arms. Patients receive a loading dose of trastuzumab (Herceptin) IV over 90 minutes followed by paclitaxel IV over 3 hours on day 0. Paclitaxel is repeated every 3 weeks for 6 courses in the absence of disease progression or unacceptable toxicity. Arm I: Patients receive trastuzumab subcutaneously (SC) weekly starting day 7. Arm II: Patients receive trastuzumab SC twice weekly starting day 7. Treatment with trastuzumab SC continues for 48 weeks in the absence of disease progression or unacceptable toxicity.