Dendritic Cell-Based Treatment Plus Immunotherapy for the Treatment of Metastatic or Unresectable Triple Negative Breast Cancer

This phase II trial tests the safety, side effects, and whether dendritic cell-based treatment and pembrolizumab work in treating patients with triple negative breast cancer that has spread to other places in the body (metastatic) or cannot be removed by surgery (unresectable). The term triple-negative breast cancer refers to the fact that the cancer cells don't have estrogen or progesterone receptors (ER or PR) and also don't make any or too much of the protein called HER2 (the cells test "negative" on all 3 tests). Dendritic cell-based treatment works by boosting the immune system (a system in our bodies that protects us against infection) to recognize and destroy the cancer cells. Pembrolizumab, is an immune checkpoint inhibitor drug, that works by targeting molecules that act as a check and balance system for immune responses. Immune checkpoint inhibitor drugs are designed to either "unleash" or "enhance" the cancer immune responses that already exist by either blocking inhibitory molecules or by activating stimulatory molecules. Giving dendritic cell-based therapy and pembrolizumab may decrease symptoms and improve quality of life in patients with triple negative breast cancer.