Breast Cancer Vaccine Can Induce Long-term Immunity

Laurie Barclay, MD

October 24, 2003

Oct. 24, 2003 — A breast cancer vaccine can induce long-term immunity, according to a presentation on Oct. 22 at the 89th Clinical Congress of the American College of Surgeons. This vaccine, targeting peptide E75 of the HER2/neu protein, which is present in one third of women with breast cancer, induced durable immune response in 12 of 14 high-risk patients.

"In our study, most, but not all, patients responded well to this treatment," senior author Craig Shriver, MD, FACS, director of the Clinical Breast Care Project at Walter Reed Army Medical Center in Washington, D.C., told Medscape.

This study enrolled 39 breast cancer patients without evidence of disease after surgery, radiotherapy, or chemotherapy, but who were at high risk for recurrence because they initially had positive lymph nodes. Of 34 who were eligible for treatment, 14 had tumors that expressed the E75 peptide on cell surfaces. These patients each received six vaccinations with E75 and granulocyte-macrophage colony stimulation as a general immunostimulant, at doses of 100 µg, 500 µg, or 1,000 µg. The remaining 20 patients served as controls.

Evidence of enhanced immunity in the vaccinated patients included increased numbers of CD8+ T-lymphocyte cells and E75-specific interferon-gamma secreting cells in the peripheral blood. Grade II toxicity occurred in two patients.

Of the 14 patients who were vaccinated, 12 generated a durable immune response to the peptide. These 12 women have had no recurrences during an average follow-up of 18 months. At five years, the expected rate of recurrence in node-positive women is 30% to 40%.

Both women who were vaccinated but did not have a durable response had recurrences, but these occurred at a median of 10 months, later than in women in the control group and in women with comparable disease. In the control group, three of 20 women had a recurrence of cancer at a median of six months.

"Based on these encouraging results from our first study in high-risk patients with positive nodes, we are now involved in a vaccination trial in node-negative women," Dr. Shriver said. "We're trying to increase eligibility for more women and to get a positive response to vaccination in patients who are not as high risk."

The Clinical Breast Care Project supported this study. The authors report no financial disclosures.

J Am Coll Surg. 2003;197:s81-s82.

Reviewed by Gary D. Vogin, MD


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