A recent study shows that the administration of a short vaccination regimen with an anti-HER2 dendritic cell vaccine consisting partly of their own cells led to complete tumor destruction in nearly 20% of women with ductal carcinoma in situ (DCIS). Moreover, more than 85% of women treated appeared to develop a long-lasting immune response following vaccination, which may reduce the risk of a more invasive cancer forming in the future.
The results of the study by researchers at the Perelman School of Medicine and the Abramson Cancer Center at the University of Pennsylvania were published online in Cancer and in the January issue of the Journal of Immunotherapy.
“I think these data more than prove that vaccination works in situations where the target is right,” says the study’s leader, Brian Czerniecki, MD, PhD, surgical director of the Rena Rowan Breast Center and surgical director of the Immunotherapy Program for the Abramson Cancer Center. “Previous vaccines targeted tissue antigens that were expressed on the cancer cells, but were not necessary for tumor survival. So a vaccine response would cause the tumor to just stop expressing the antigen and the tumor would be fine. Here we’re going after HER2/neu, which is critical for survival of early breast cancers. If we knock it out with the immune response, we cripple the tumor cells.”
The study included 27 women with HER2-positive DCIS. Each patient received 4 shots of their personalized anti-HER2 vaccine, administered 1 week apart. Two weeks after completion of the vaccine therapy, patients had surgery to remove any remaining disease.
When pre-vaccination biopsy samples were compared with post-vaccination surgical samples, researchers observed remarkable changes:
- At the time of surgery, 5 patients had no visible disease, indicating their immune system had eliminated the tumor
- Of the remaining 22 patients, HER2 expression was nonexistent in half (11 patients)
- HER2 expression was reduced by 20% or more in 2 patients
“We are continuing to see this pattern in our second, ongoing trial,” Czerniecki says.
When immune responses were examined, Czerniecki and team found HER2-reactive CD4 and CD8 T cells in 85% of patients, suggesting the development of strong and relatively complete immune responses following vaccination. Importantly, some patients sustained their immune responses as long as 52 months.
The vaccine is safe, according to study results. The most common reported side effects were malaise (72%), injection site soreness (59%), chills or rigors (38%), fever (28%), and headache (24%).
Source: Penn Medicine.