A Study of Liposomal Doxorubicin+Docetaxel+Trastuzumab+Metformin in Operable and Locally Advanced HER2 Positive Breast Cancer

Multi-center, open-label phase II trial to assess activity of this chemotherapy scheme evaluated by pathologic complete response rate (pCR). Planned treatment are 6 cycles of chemotherapy. At every cycle (every 21 days) will be administered: Day 1: Liposome-encapsulated doxorubicin, 50 mg/m2 IV 1 hour infusion; Day 2 and 9: Docetaxel, 30 mg/m2 IV 1 hour infusion; Day 2, 9 and 16: Trastuzumab 4 mg/kg for the first infusion loading dose, then 2 mg/kg/week for subsequent injections Day -13 to 0: Metformin is administered as single agent. From day -13 to day -11, Metformin 1000 mg will be administered once a day; from day -10 Metformin 1000 mg will be administered twice a day continuously until end of the study treatment. Total duration of the trial: 36 months Enrollment period: 24 months Treatment: maximum of 6 cycles (5 months) per patient Follow-up for recurrence: every six months for 5 years, than once a year until 10 years after surgery.It's necessary to recruit 46 patients for clinical objectives evaluation.