Nelipepimut-S Plus GM-CSF Vaccine Therapy in Treating Patients With Breast Cancer

PRIMARY OBJECTIVE: I. Evaluate for nelipepimut-S-specific cytotoxic T lymphocyte (CTL; cluster of differentiation \[CD\]8+ T cell) response in patients receiving NeuVax (nelipepimut-S plus GM-CSF \[sargramostim\]) compared to patients receiving GM-CSF alone (control). SECONDARY OBJECTIVES: I. Toxicity profile and frequency of adverse events in women with ductal carcinoma in situ (DCIS) of the breast receiving nelipepimut-S vaccine as compared to women receiving GM-CSF alone. II. Presence of DCIS at resection. III. Difference in HER2 expression in the biopsy and the surgical specimen excised post-vaccination. IV. Histologic responses: IVa. Degree of lymphocyte infiltration determined on hematoxylin and eosin (H\&E) stained slides and immune infiltration as determined by multiplex immunofluorescence staining for markers including but not limited to CD3, CD4 and CD8. IVb. Immune infiltrates in normal tissue maximally distant from the tumor (in mastectomy samples). OUTLINE: Patients are randomized to 1 of 2 arms. ARM I: Patients receive nelipepimut-S plus GM-CSF vaccine intradermally (ID) on days 0 and 14 and then undergo surgery on day 28. ARM II: Patients receive sargramostim ID on days 0 and 14 and then undergo surgery on day 28. After completion of study treatment, patients are followed up at 1 and 3 months.