This is an open-label, single-arm, multicenter, Phase IIIb study to evaluate the safety and tolerability of Herceptin SC in combination with Perjeta IV plus docetaxel in female patients with HER2-positive metastatic or locally recurrent breast cancer. Enrolled patients are to receive study medication until disease progression, unacceptable toxicity, withdrawal of consent, death, or predefined study end, whichever occurs first. The anticipated time on study treatment is approximately 24 months. The target sample size is 400.