Good news for breast cancer patients: A post-treatment vaccine currently in its second phase of clinical trial at Houston's M.D. Anderson Cancer Center has proven to prevent disease recurrence by a significant margin.

Patients on the vaccine were 43 percent less likely to have a cancer recurrence. The secret weapon is AE37, a peptide vaccine that helps the body to raise immunity against HER2, the growth-promoting oncoprotein present in nearly 80 percent of breast cancer tumors.

Dr. Elizabeth Mittendorf, assistant professor in the Department of Surgical Oncology at M.D. Anderson and principal investigator for the nation-wide study, told CultureMap that preliminary results suggest the AE37 vaccine may benefit patients with low levels of HER2 expression as well, when used in conjunction with other adjuvant treatments.

"The vaccination has been met with enthusiasm by the researchers and the patients," Mittendorf tells CultureMap.

After completing treatment from an oncologist, the patient begins receiving the primary vaccination series — monthly inoculations for six months. To increase efficacy, booster shots are given to the patient every six months over the next three years (the window of time that patients see the greatest risk of recurrence). Side effects are typically minimal.

Such is the case with Ann Cassady, an M.D. Anderson patient from Knoxville, Tenn., who underwent a double mastectomy, one lymphadenectomy, six months of chemotherapy and a month and a half of radiation before signing up for the study in February.

"I just had a treatment this morning," Cassady says. "I've experienced no side effects whatsoever."

Cassady flies to Houston once a month, receives two AE37 shots in her leg, then stays for 48 hours to check up with the doctors. Cassady said the after-effects of the inoculation are comparable to a mosquito bite itch.

The study finds that, at a 22-month follow up, former breast cancer patients had a 10.3 percent recurrence rate (compared to 18 percent in a control group). Those conclusions will be presented on June 4 at the annual meeting of the American Society of Clinical Oncology.

A third phase of the study will follow after Antigen Express, the company that licenses the AE37 technology, applies for a special protocol assessment from the FDA.