Phase Ib Trial of HER2/Neu Peptide (E75) Vaccine in Breast Cancer Patients at Risk for Recurrence After Surgical and Medical Therapies

Breast cancer is the most common malignancy and second most common cause of cancer-specific death among women in the United States. Despite advances in the diagnosis and treatment of breast cancer, one third of the women who develop the disease will die of the disease, accounting for approximately 46,300 deaths/year. While good primary therapies are available to treat early stage breast cancer, there is a substantial failure rate to these therapies in more advanced disease.

Advances in the understanding of the immune response to cancer have lead to the genesis of immunotherapeutic approaches. Specifically, the development of anti-cancer vaccines holds promise as an adjuvant and preventive therapy for patients after both primary surgical and medical treatment for breast cancer, but who are at a high risk for recurrence. Patients with greater than four lymph nodes positive have an 87% chance of recurrence post standard surgical and medical therapies at 10 years. While patients with hormone receptor positive tumors have the option to undergo hormonal therapy, recurrence is especially high among estrogen receptor/progesterone receptor (ER/PR) negative patients. For these patients, currently there is no good treatment option after completion of primary therapy; close surveillance and watchful waiting is the standard.

It is this population of patients that a vaccine strategy to induce cellular immunity would target. We propose to vaccinate these patients with an immunogenic peptide from the HER2/neu protein. If successful, this vaccine strategy could be utilized as an adjuvant to currently accepted first line therapy in future clinical trials.