OUTLINE: Patients receive pertuzumab intravenously (IV) over 30-60 minutes on day 1, trastuzumab IV over 30-90 minutes and paclitaxel albumin-stabilized nanoparticle formulation IV over 30 minutes on days 1, 8, and 15. Treatment repeats every 21 days in the absence of disease progression or unacceptable toxicity (patients with MBC) or for 6 courses in the absence of disease progression or unacceptable toxicity (patients with LABC).