Allison Gandey
                                                                                                                    December 18, 2006 (San Antonio) –- A new vaccine aimed at reducing recurrence in high-risk breast cancer patients rather than treating metastatic disease is sparking interest. Researchers presenting here at the 29th Annual San Antonio Breast Cancer (SABC) Symposium say the vaccine showed a consistent 50% reduction in recurrence in disease-free, conventionally treated patients. But the finding lost statistical significance in its most recent analysis, the researchers say, because of small trial numbers. “This was a small, nonrandomized phase 2 study, but the results are intriguing, and we have applied to proceed to the next phase of testing,” lead investigator Col. George Peoples, MD, from the Cancer Vaccine Development Laboratory, in Bethesda, Maryland, told reporters at the meeting.
Under development by Apthera in Scottsdale, Arizona, the HER2/neu vaccine is known as E75 after its immunogenic peptide. HER2/neu is a proto-oncogene in the epidermal growth factor receptor family and is overexpressed in an estimated 25% of breast cancer patients. The researchers conducted 2 overlapping sequential trials of the vaccine in node-positive breast cancer patients enrolled in a safety study and node-negative patients enrolled in a dose-optimization study. They report the vaccine demonstrated promising immunologic responses and can be administered safely with minimal local or systemic toxicity.
E75 Vaccine Trial Findings at a Median of 24 Months

Commenting on the trial for Medscape, Gary Chamness, PhD, from the Baylor College of Medicine, in Houston, Texas, said that vaccines have been a difficult area of study. “The fact that this group was able to show an immunologic response is very positive,” said Dr. Chamness, who was not involved in the study. “Now, this is a long way from saying this is something we’re going to be giving everybody next week or next month, but this is certainly something to keep an eye on.”
Dr. Chamness critiqued the lead investigator’s repeated use of the word “prevention” in his presentation. “Usually when we talk about prevention, we mean people who may be at risk but who haven’t had cancer, and we seek to prevent disease. In his trial, that’s not what the researchers were doing — it’s more of an adjuvant trial for people who’ve had breast cancer, had surgery, and had no other evidence of disease.”
Tapping Into the Body’s Naturally Occurring Immunity
During a news conference, Dr. Peoples told reporters that vaccines are typically initiated in patients with metastatic disease because these patients are generally more willing to try experimental therapies. But, he notes, testing vaccines in this setting is far from ideal. “You don’t take the flu shot when you have the flu — it’s best when your immune system is intact so that the body can detect it.”
The work, which was initially sponsored by the US Department of Defense and conducted at the Brooke Army Medical Center in Fort Sam Houston, Texas, aims to target the body’s naturally occurring immunity and source of immunogenic peptides. The vaccine consists of the E75 peptide mixed with granulocyte-macrophage colony-stimulating factor and was administered in monthly intradermal injections.
“It’s a very basic vaccine,” Dr. Peoples said. “No one really believed that a simple vaccine like this could work — not even me, at first.”
29th Annual SABC Symposium: Abstract 4. Presented December 14, 2006.