Ivermectin in Combination With Balstilimab or Pembrolizumab in Patients With Metastatic Triple Negative Breast Cancer

Inclusion Criteria: * Age: ≥ 18 years * Eastern Cooperative Oncology Group (ECOG) ≤ 1 * Life expectancy \> 3 months * Histologically confirmed metastatic triple negative breast cancer. Triple negative status will be defined as estrogen receptor (ER) and progesterone receptor (PR) ≤ 10% and HER2 negative (by immunohistochemistry \[IHC\] or fluorescence in situ hybridization \[FISH\]), per American Society of Clinical Oncology (ASCO)/College of American Pathologists (CAP) guidelines * Patients must have progressed on 1-2 prior lines of systemic therapy (chemotherapy and/or drug-antibody conjugate) in the metastatic setting * Measurable or evaluable disease by Response Evaluation Criteria in Solid Tumors (RECIST) 1.1. Lesions situated in a previously irradiated area are considered measurable if progression has been demonstrated in such lesions * Fully recovered from the acute toxic effects (except alopecia) to ≤ grade 2 from prior anti-cancer therapy * For Phase 2 expansion only, must be PD-L1 negative. Note: For Phase 1 safety cohort, any PD-L1 status will be allowed to enroll. * Patients must have adequate organ function as defined in the following: * Absolute neutrophil count (ANC) ≥ 1,500/mm\^3 * Platelets ≥ 100,000/mm\^3 * Hemoglobin ≥ 9.0 g/dL or ≥ 5.6 mmol/L. Criteria must be met without erythropoietin dependency and without packed red blood cell (pRBC) transfusion within last 2 weeks * Total serum bilirubin ≤ 1.5 x upper limit of normal (ULN) OR direct bilirubin ≤ ULN f…