Folate Receptor Alpha Peptide Vaccine With GM-CSF in Patients With Triple Negative Breast Cancer

This Phase II trial evaluates the safety and immunogenicity of two doses of the Folate Receptor Alpha (FRα) peptide vaccine mixed with GM-CSF as a vaccine adjuvant, with or without a immune priming with cyclophosphamide, as a consolidation therapy after neoadjuvant or adjuvant treatment of patients with Stage IIb-III triple negative breast cancer (TNBC).

Triple negative breast cancers (TNBCs) occur in approximately 20-25% of all patients with breast cancer and are associated with a poor prognosis. Patients with TNBCs derive no benefit from targeted therapies. Excluding those patients who demonstrate a pathologic complete response following neoadjuvant chemotherapy, which is a minor fraction (i.e. 15%), overall survival is only 45% at 7 years. Following standard of care, there are windows of opportunity to further and safely treat patients to prevent recurrence. Stimulating the immune system to produce T cells immunity specific for tumor antigens may significantly delay recurrence and cure patients. The proposed vaccine is intended to induce T cells to survey for the reemergence of TNBCs and to prevent recurrence in the adjuvant setting. The vaccine strategy is antigen-specific and targets the Folate Receptor Alpha (FRα). FRα is an ideal target because of its limited expression in the healthy tissues and it high expression in 86% of TNBCs. Studies have shown that it is a biologically important marker that is associated with poorer clinical outcome and is retained in metastatic lesions. The FRα vaccine include a pool of 5 peptides that are immunogenic epitopes and safely generate tissue-surveying CD4 T cell immune responses in patients tested in a recently completed phase I clinical trial.