AACR: HER2/neu E75-Peptide Vaccine Effective
In early-stage breast cancer, vaccination leads to favorable outcomes in high and low expressers
MONDAY, April 14 (HealthDay News) -- In patients with early-stage breast cancer, those with all levels of HER2/neu expression have favorable responses and outcomes after receiving the HER2/neu E75-peptide vaccine, according to research presented this week at the annual meeting of the American Association for Cancer Research in San Diego.
Linda C. Benavides, M.D., of the Brooke Army Medical Center in Ft. Sam Houston, Texas, and colleagues assessed 165 patients based on their level of HER2/neu expression. Of these, 94 were vaccinated (including 30 over-expressers and 64 low-expressers) and 71 served as controls (including 22 over-expressers and 49 low-expressers).
The researchers found immunologic responses to the vaccine were similar in both over-expressers and low-expressers, although over-expressers had a decreased number of E75-specific CD8+ T cells compared to low-expressers. After a median follow-up of 30 months, they found that disease recurrence rates were similar between vaccinated over-expressers and control over-expressers (4.3 percent versus 5.6 percent) but that vaccinated over-expressers with recurrence had a significantly lower mortality rate (25 percent versus 50 percent). They also found that recurrence rates were significantly lower in vaccinated low-expressers than in control low-expressers (6.4 percent versus 11.3 percent).
"Unexpectedly, patients with low-expressing (0 - 2+ on IHC) HER2/neu tumors show better response not only immunologically, but clinically with decreased breast cancer recurrence and 0 percent mortality following E75 peptide vaccination," the authors conclude.