This Phase Ib study will investigate the safety and anti-tumor activity of daily oral doses MEN1611 in combination with Trastuzumab with/without Fulvestrant in female and male patients affected by advanced or metastatic HER2-positive breast cancer. Fulvestrant will be added to the post-menopausal patients with hormone-sensitive disease.~MEN1611 is an investigational drug which blocks a protein called PI3K (phosphoinositide 3-kinase) involved in cancer cells growth. The Maximum Tolerated Dose (MTD) of MEN1611 given as single agent was assessed in a phase I trial in patients with advanced solid tumors.~This Phase IB will start with a dose escalation part (Step 1) to identify the MTD of MEN1611 given in combination with Trastuzumab with/without Fulvestrant.~The study will continue with a cohort expansion (Step 2) to investigate the anti-tumor activity of the selected MEN1611 dose level considered to be tolerable by a Safety Review Committee.
The main purpose of this open-label, dose-escalation, phase Ib study is to identify the appropriate dose of MEN1611 to be used in combination with Trastuzumab with/without Fulvestrant for the treatment of advanced or metastatic HER2-positive breast cancer