A Vaccine (STEMVAC) for Improving Survival in Patients With Triple-Negative Breast Cancer and Moderate or Extensive Residual Cancer Burden

Inclusion Criteria: * At least 18 years of age * Eastern Cooperative Oncology Group (ECOG) performance status score of ≤ 2 * Triple-negative breast cancer as determined by the treating oncologist * Completed standard of care neoadjuvant chemotherapy in the opinion of their treating oncologist * Patients whose tumors progress on neoadjuvant therapy may be enrolled * No clinical evidence of local or distant recurrence * Plan to receive standard of care adjuvant directed therapy * Completed standard of care locoregional treatment, including definitive breast and lymph node surgery followed by standard radiation therapy, if recommended * Residual cancer burden (RCB) index 2 or 3 as calculated per routine anatomic pathology clinical standards * Absolute neutrophil count (ANC) ≥ 800/μL (within 30 days of first study vaccine administration) * Hemoglobin (Hgb) ≥ 8 g/dL (within 30 days of first study vaccine administration) * Platelets ≥ 75,000/ μL (within 30 days of first study vaccine administration) * Total bilirubin ≤ 1.5 x institutional upper limit of normal (ULN), except patients with Gilbert's syndrome, in whom total bilirubin must be \< 3.0 mg/dL (within 30 days of first study vaccine administration) * Aspartate aminotransferase (AST)/alanine aminotransferase (ALT) ≤ 1.5 x institutional ULN (within 30 days of first study vaccine administration) * Creatinine ≤ 1.5 x ULN mg/dL or creatinine clearance \> 60 mL/min (within 30 days of first study vaccine administration) * At least…