This is a randomized, prospective and multicenter phase III study. Two-hundred-sixty-two (262) patients on each arm will be recruited in the study.

The primary objective is time to disease progression. All patients must be treated with first line chemotherapy, consisting of one of the following regimens: a) ET (epirubicin 90 mg/sqm day 1 plus paclitaxel 200 mg/sqm (3 hour infusion) day 1, or b) AT (doxorubicin 50 mg/sqm day 1 plus paclitaxel 200 mg/sqm (3 hour infusion) day 2, administered on a 3 weekly schedule.

Patients with complete response, partial response or stable disease are eligible for MANTA1 study.

The expected median progression free survival of metastatic breast cancer patients who achieve a disease control after first line chemotherapy was estimated to be 10 months. The minimal improvement, justifying the adoption of maintenance paclitaxel, was estimated to be at least 3 months. With 262 eligible patients on each arm, the trial will have a power of 80% to detect a 30% improvement in median progression free survival, testing at the two-sided .05 significance level.

Inclusion Criteria:

• Written informed consent.
• Patients with metastatic breast cancer in response or stable disease after six to eight courses of first line induction chemotherapy treatment
• Measurable and/or evaluable disease
• Performance status ECOG 0, 1, 2.
• Normal cardiac function, confirmed by left ventricular ejection fraction (LVEF).

Exclusion Criteria:

• Presence of peripheral neuropathy > grade 2 by NCI Common Toxicity Criteria (NCI-CTC) following induction chemotherapy
• Adjuvant taxane-based therapy