SAN ANTONIO, Dec. 14 (UPI) -- An experimental vaccine to prevent recurrence of breast cancer performed well enough in preliminary studies for investigators to seek government approval to pursue its development.
In the preliminary trial, the vaccine appears to reduce the risk of recurrence by about 50 percent, researchers said Thursday at the 29th annual San Antonio Breast Cancer Symposium.
"Patients who received the vaccine had a recurrence rate of 8.3 percent after 24 months, compared with patients who did not receive the vaccine, who recurred at the rate of 16 percent," said Col. George Peoples, a surgeon at Brooke Army Medical Center, Fort Sam Houston, who conducted the study while at Walter Reed Army Medical Center in Washington.
Because the numbers of women enrolled in the study was small -- 101 women were vaccinated and 85 other women acted as controls -- the difference in outcomes did not reach statistical significance, technically meaning that the study failed to show the vaccine worked.
However, the phase 1/2 study appeared to be biased against the vaccine, and yet missed is primary goal because one woman recurred within the last four months. Peoples told United Press International that the overall outcome was substantial enough for researchers to approach the Food and Drug Administration for a major vaccine trial that could result in approval for the treatment. Meetings to write protocols for that trial will begin early next year.
"It's possible that we could begin recruitment for the trial in late summer of 2007," he said.
The E75 vaccine targets a gene called HER2, a molecule found in abundance in certain aggressive breast cancers, but also found to some degree in most breast cancers. A fragment of the HER2 gene is incorporated into the vaccine as an immune-system stimulant.
Under an optimal schedule, women who were clinically free of breast cancer following surgery and post-surgery chemotherapy or radiation would receive one injection of the vaccine into the skin every month for six months.
Peoples said that, because researchers were working to achieve the best schedule and dose of E75 -- 1,000 micrograms in a milliliter injection into the skin -- only one-third of the women getting the vaccine received the optimal dose, a factor that may have played against the vaccine.
One of the women who received the vaccine, Cynthia Gilman, 46, an attorney from Alexandria, Va., said, "I wanted to take the vaccine because I wanted to do every thing I could to prevent any breast-cancer recurrence."
Gilman, a high-risk breast-cancer patient, was first diagnosed in 2003. Identified as a high-risk patient, and the mother of a 4-month-old adopted child, she said she chose an aggressive treatment regimen to enhance her survival chances. She underwent double mastectomy, took six months of chemotherapy instead of four and opted to receive radiation. When she heard about the work on the vaccine, she asked to be included in that group as well.
"I am excited about the vaccine and about participating in the program," she told UPI. She said she was recently contacted by the vaccine program to receive a booster of E75. She has remained cancer-free.
"These results are extremely preliminary," Eric Winer, director of the breast oncology program at Dana-Farber Cancer Institute in Boston, told UPI. "It certainly is worthwhile doing a clinical trial. Everyone wants a vaccine for breast cancer."
Despite numerous attempts at vaccines to treat or prevent breast cancer, there has never been a successful breast-cancer vaccine.
Peoples said the vaccine is still years from commercial development even if it successfully hurdles regulatory obstacles. Peoples said the vaccine will be developed further by Apthera Inc. in Scottsdale, Ariz. The company has named the vaccine NeuVax.
The initial trials were sponsored by grants from the Department of Defense's congressionally mandated breast-cancer program.
