vaccine therapy with or without polysaccharide-k in patients with stage iv her2 positive breast cancer receiving her2-targeted monoclonal antibody therapy

Conditions: HER2/Neu Positive; Recurrent Breast Carcinoma; Stage IV Breast Cancer

Summary: this randomized phase i/ii trial studies the side effects of vaccine therapy with or without polysaccharide-k and to see how well it works in treating patients with stage iv human epidermal growth factor receptor 2 (her2) positive breast cancer who are receiving her2-targeted monoclonal antibody therapy. vaccines made from her2 intracellular domain (icd) peptide may help the body build an effective immune response to kill tumor cells that express her2. polysaccharide-k may stimulate the immune system in different ways and stop tumor cells from growing. it is not yet known whether vaccine therapy works better when given with or without polysaccharide-k in treating breast cancer.

primary objectives: i. to evaluate the safety of polysaccharide-k (psk) when given with her2-directed immunotherapy. secondary objectives: i. to evaluate the effect of psk on natural killer (nk) cell functional activity when given with her2-directed immunotherapy. tertiary objectives: i. to investigate the effect of psk when given with her2-directed immunotherapy on: serum levels of pro-inflammatory cytokine and/or chemokines; intermolecular epitope spreading; serum transforming growth factor (tgf)-beta levels; progression free survival (pfs) and overall survival (os). outline: patients are randomized to 1 of 2 treatment arms. arm i: patients receive her2 icd peptide-based vaccine intradermally (id) once monthly for 3 months, trastuzumab (or trastuzumab and pertuzumab) per standard of care, and placebo orally (po) twice daily (bid) for 4 months. arm ii: patients receive her2 icd peptide-based vaccine id and trastuzumab (or trastuzumab and pertuzumab) as in arm i and polysaccharide-k po bid for 4 months. after completion of study treatment, patients are followed up for 9 months and then twice annually for 3 years.

Eligibility criteria:
inclusion criteria: * patients with stage iv her2+ breast cancer treated to: * no evidence of disease (ned), or * stable bone only disease after definitive therapy * her2 overexpression by immunohistochemistry (ihc) of 2+ or 3+ in the primary tumor or metastasis; or documented gene amplification by fluorescent in situ hybridization (fish) analysis; ihc =\< 2+ must have her2 gene amplification documented by fish * patients must continue her2-targeted monoclonal antibody therapy dosing per standard of care through the entire study period (one year) * her2-targeted monoclonal antibody therapy is defined as either trastuzumab monotherapy, or trastuzumab and pertuzumab combination therapy administered per standard of care * patients must be at least 21 days post cytotoxic chemotherapy prior to enrollment * patients must be at least 28 days post immunosuppressants prior to enrollment * patients must be at least 28 days from use of any mushroom supplements (examples: turkey tail, reishi, maitake, shiitake) and agree to withhold them for the entire study period (one year) * patients on bisphosphonates and/or endocrine therapy are eligible * patients who are having sex that could lead to pregnancy must agree to contraceptive use during the entire study period * patients must have zubrod performance status score of =\< 2 * patients must have recovered from major infections and/or surgical procedures, and in the opinion of the investigator, not have significant active concurrent medical illnesses precluding study treatment * white blood cell (wbc) \>= 3000/mm\^3 * hemoglobin (hgb) \>= 10 g/dl * serum creatinine =\ 60 ml/min * total bilirubin =\< 1.5 mg/dl * serum glutamic oxaloacetic transaminase (sgot) =\< 2.5 times the upper limit of normal * patients must have adequate cardiac function as demonstrated by normal left ventricular ejection fraction (lvef) \>= the lower limit of normal for the facility on multi gated acquisition (muga) scan or echocardiogram (echo) within 3 months of enrollment exclusion criteria: * patients with any of the following cardiac conditions: * restrictive cardiomyopathy * unstable angina within 6 months prior to enrollment * new york heart association functional class iii-iv heart failure * symptomatic pericardial effusion * patients with any contraindication to receiving rhu granulocyte macrophage colony stimulating factor (rhugm-csf) based products * patients with any clinically significant autoimmune disease requiring active treatment * patients receiving any concurrent immunosuppressants * patients who are pregnant or breast-feeding * patients who are simultaneously enrolled in other treatment studies * patients who have received a previous her2 breast cancer vaccine * known hypersensitivity reaction to mushroom products