Arm A: Experimental Arm (n=82) Part I (Week 1-12) Epirubicin 90 mg/m2 by IV infusion on Day 1 every 21 days Cyclophosphamide 600 mg/m2 by IV infusion on Day 1 every 21 days Lapatinib 1000 mg orally once daily continuously Loperamide as required for the proactive management of diarrhoea (see Section 5.13.6)