Her2-BATS and Pembrolizumab in Metastatic Breast Cancer

This proposal uses HER2Bi armed activated T-cells (HER2 BATs) to target breast cancer in combination with pembrolizumab (PBZ) in women with metastatic breast cancer (MBC). Phase I will determine a safe dose of the combination of PBZ and HER2 BATs in 3 to 18 patients. In the phase II portion, an additional 12 patients will be treated at the selected dose to further evaluate the safety and preliminary efficacy. Study treatment includes a combination of 8 infusions of BATs using a previously established schedule and one to three infusions of PBZ (200 mg per dose). PBZ will be added to 8 infusions of BATs in 3 schedules: #1) after the 8th BATs infusion; #2) after the 4th and 8th BATs infusions; and then, #3) before the 1st and after the 4th and 8th BATs infusions.