Vaccine Therapy in Treating Patients With HER2-Negative Stage III-IV Breast Cancer

PRIMARY OBJECTIVES:

I. To determine the safety of intradermal administration of up to 3 escalating doses of
STEMVAC (CD105/Yb-1/SOX2 CDH3/MDM2-polyepitope plasmid DNA vaccine) in patients with
HER2-negative advanced stage breast cancer.

II. To determine the most immunogenic dose of STEMVAC in patients with HER2-negative advanced
stage breast cancer.

SECONDARY OBJECTIVES:

I. To determine whether a STEMVAC T helper 1 cells (Th1) polyepitope plasmid based vaccine
elicits a persistent memory T cell response and whether immunity can be further
enhanced/maintained by two additional STEMVAC vaccines (boosters) given 3 and 9 months after
the priming regimen.

II. To evaluate whether STEMVAC vaccination modulates T regulatory cells and myeloid-derived
suppressor cells (MDSC).

OUTLINE: This is a dose-escalation study.

Patients receive CD105/Yb-1/SOX2/CDH3/MDM2-polyepitope plasmid DNA vaccine with recombinant
human granulocyte-macrophage colony-stimulating factor (rhuGM-CSF) intradermally (ID) every
28 days for 3 months and booster vaccines at 6 and 12 months in the absence of disease
progression or unacceptable toxicity.

After completion of study treatment, patients are followed up twice yearly for 5 years.

Inclusion Criteria:

- Patients with stage III-IV HER2 negative breast cancer treated with primary or salvage
therapy and now have:

- No evidence of disease (NED), or

- Stable bone only disease

- Patients who have completed standard of care and recovered with mild to no residual
toxicity from recent therapy

- Patients must be at least 28 days post cytotoxic chemotherapy, and/or monoclonal
antibody therapy (excluding bone-directed therapy), prior to enrollment

- Patients must be at least 28 days post systemic steroids prior to enrollment

- Patients on bisphosphonates, denosumab, and/or endocrine therapy are eligible

- Patients must have Eastern Cooperative Oncology Group (ECOG) performance status score
of =< 1

- Patients must have recovered from major infections and/or surgical procedures, and in
the opinion of the investigator, not have any significant active concurrent medical
illnesses precluding protocol treatment

- Estimated life expectancy of more than 6 months

- White blood cells (WBC) >= 3000/mm^3

- Lymphocyte count >= 800/mm^3

- Platelet count >= 75000/mm^3

- Hemoglobin (Hgb) >= 10 g/dl

- Serum creatinine =< 1.2 mg/dl when adjusted for body surface area (BSA) or creatinine
clearance > 60 ml/min

- Total bilirubin =< 1.5 mg/dl

- Aspartate aminotransferase (AST)/serum glutamic oxaloacetic transaminase (SGOT) =< 2
times upper limit of normal (ULN)

- Blood glucose < 1.5 ULN

- All patients who are having sex that can lead to pregnancy must agree to contraception
for the duration of study

Exclusion Criteria:

- Patients with any of the following cardiac conditions:

- Symptomatic restrictive cardiomyopathy

- Unstable angina within 4 months prior to enrollment

- New York Heart Association functional class III-IV heart failure on active
treatment

- Symptomatic pericardial effusion

- Patients at risk for gastrointestinal bleeding (example: peptic ulcer disease,
prolonged daily non-steroidal anti-inflammatory use)

- Patients with any seizure disorder

- Patients with any contraindication to receiving rhuGM-CSF based products

- Patients with any clinically significant autoimmune disease uncontrolled with
treatment

- Patients who are simultaneously enrolled in any other treatment study

- Patients who are pregnant or breastfeeding