The Package Insert for Leukine® is enclosed in this Protocol as Appendix H. Allow the E75 acetate or control to warm to room temperature and the Leukine® to warm to room temperature. Using aseptic technique with a 1 mL syringe and provided needle, withdraw 0.8 mL from the test drug vial (E75 or control) and inject the syringe containing 0.8 mL of test drug into the reconstituted Leukine. Keeping the vial upright, slowly roll the Leukine/Test Drug vial between your hands. Allow any foaming to dissipate before continuing. Do not invert the vial. This assures the complete mixing of the E75 acetate or control and Leukine® solutions (see detailed guidance in Appendix G for vaccine and DTH preparation). Discard the mixing syringe and needle. Once E75 or the control have been mixed, the four provided 1 mL syringes are used to withdraw equal volumes into each, and thus a total of 1.6 mL of the solution is withdrawn for administration. The syringes are now ready to be used for inoculation and must be used within 6 hours of mixing. If dose reduction of GM-CSF is required based on >100 mm x 100 mm induration, and/or ≥Grade 3 toxicity at the injection site after the previous dose, the liquid Leukine® vial is diluted with an additional 1.0 mL WFI, using aseptic technique, and mixed gently by rolling the Leukine vial between your hands. Allow any foaming to dissipate before continuing. Do not invert the vial. Subsequently, 1 mL is withdrawn and discarded and the remaining 1 mL is used for mixing following the same methodology above to make a 1.6 mL Leukine + E75 mixture. Further dilutions (approximately 1:1) may be required if >10 cm erythema and induration and/or ≥ Grade 3 toxicity are observed on subsequent doses, the details of which will be provided in study instructions. b. Storage For detailed storage instruction of the vaccine and its components (E75 acetate in WFI and GM-CSF) please follow the instructions in the Investigator’s Brochure. Stability data support storage of E75 acetate in WFI and control to E75 acetate in WFI at -20°C (± 5°C) or 5°C (± 3°C). Store study drug (E75 acetate in WFI, control to E75 acetate in WFI, and GM-CSF) as per appropriate storage temperature designated on clinical carton label. 4.3.6 Inoculation Series - administration CONFIDENTIAL Page 29 of 102 Protocol: HERCEPTIN® + E75/GM-CSF Version 3.1 ML25749 05 March 2017 Patients will receive 4 intradermal inoculations on the anterior or medial side of the same thigh. The general area of inoculation will be at a location midway between the inguinal ligament and the knee. The 1.6 mL by volume vaccine (or GM-CSF alone) will be administered intradermally in four equal inoculums at four different sites in a square configuration 5 cm from each other. Inoculations will be given every three weeks and will be administered in the same lymph node draining area (same arm or leg). Timing of the inoculation series with Herceptin treatment will occur as outlined in Section 3.1 (see also Appendix A). The dose will be 1000 mcg of E75 peptide and 250 mcg of GM-CSF. The research nurse coordinator will administer the inoculations sterilely in the vaccine or clinical laboratory facility located at each study site. For female patients with childbearing potential, a urine pregnancy test will be performed before each inoculation. If this test is positive at any time, the patient will be discontinued from the study. 4.3.7 Booster Inoculations After completion of the six-inoculation primary vaccine series, patients will then receive a total of four booster inoculations to be administered, every 6 months x4 for total combination (Herceptin and/or Vaccine) treatment duration of 30 months (Appendix A). As discussed in Section 3.1, the first booster inoculation will occur at the time of the final Herceptin infusion with subsequent boosters timed every 6 months (± 2 weeks) from the first booster and should be administered in the same extremity as the primary series. Booster inoculations will consist of the same intervention as each patient received during their regular inoculation series. Patients enrolled to the E75/GM-CSF vaccine arm of the trial will receive four consecutive booster inoculations of 1000 mcg E75 peptide + 250 mcg GM-CSF, and patients enrolled to the GM-CSF alone arm will receive four consecutive booster inoculations of 250 mcg GM-CSF only. For patients with childbearing potential, a urine pregnancy test will be performed before each booster inoculation.