Phase II Trial of Combination Immunotherapy With NeuVax and Trastuzumab in High-risk HER2+ Breast Cancer Patients

At the time of vaccine administration, a frozen solution of E75 acetate (1.5 mg/mL) is thawed and 1000mcg E75 peptide mixed thoroughly with 250mcg GM-CSF. This constitutes the NeuVax vaccine. Patients randomized to this arm will receive vaccinations of nelipepimut-S/GM-CSF administered intradermally every three weeks for six total vaccinations, 30-120 minutes after completion of trastuzumab infusion. The first vaccination will be given with the third dose of maintenance trastuzumab administered as monotherapy optimally, but may be given with later maintenance doses of trastuzumab, provided there are at least six remaining doses of trastuzumab to overlap with the primary vaccine series.

Herceptin will be administered to patients every three weeks as monotherapy for one year, to be given upon completion of standard of care chemotherapy/radiotherapy. The first trastuzumab infusion will be given no sooner than three weeks and no later than 12 weeks after completion of chemotherapy/radiotherapy. Trastuzumab will be dosed at the recommended initial loading dose of 8 mg/kg and at recommended maintenance doses of 6 mg/kg q3wk.

For patients randomized to the GM-CSF alone arm, they will receive inoculations of GM-CSF (250mcg) administered intradermally every three weeks for six total vaccinations, 30-120 minutes after completion of trastuzumab infusion. The first injection will be given with the third dose of maintenance trastuzumab administered as monotherapy optimally, but may be given with later maintenance doses of trastuzumab, provided there are at least six remaining doses of trastuzumab to overlap with the primary vaccine series.