Personalized Vaccine Shows Promise in Early HER2-Positive Breast Cancer
While HER2-positive breast cancer survival rates have improved thanks to HER2-targeted therapies, chemotherapy is still a required part of treatment. The standard chemotherapy regimen is associated with high toxicity, which brings many unwanted side effects.
Moffitt Cancer Center launched a study to investigate if a dendritic cell vaccine could enhance immune response and potentially reduce or eliminate the need for chemotherapy in patients with stage 1-3 HER2-positive breast cancer.
The phase 1 trial results, published in JAMA Oncology, show HER2-targeted therapies combined with the HER2 vaccine before deescalated chemotherapy was safe and well tolerated.
Heather Han, MD
“We have always known that immune response is very important for patients who are receiving even standard chemotherapy, but that can’t be achieved for all patients,” said lead study author Heather Han, MD. “Adding high-dose immunotherapy using a dendritic cell vaccine to the tumor could essentially enhance cell infiltration and help patients achieve good responses to treatment, which potentially suggests maybe less intensive chemotherapy will be needed.”
Dendritic cells are a special type of immune cell that boosts immune responses by highlighting foreign cells for the immune system to attack. They are harvested from a patient’s blood and used to create the personalized vaccine. The vaccine is injected directly into a breast tumor under ultrasound guidance.
Twelve patients on the trial received a weekly dendritic cell vaccine injection for six weeks, followed by a deescalated chemotherapy regimen with weekly paclitaxel for 12 weeks. They were also given HER2-targeted therapies (trastuzumab and pertuzumab) every three weeks. Breast MRIs taken throughout the course of treatment showed nine patients had objective responses (six partial responses and three complete responses) and three with stable disease. Seven patients had a complete pathologic response following surgery.
“We added an immune stimulant in the form of our dendritic cells that we injected increasing doses into the breast combined with two antibodies and together they made the tumors shrink, in some cases almost completely,” said Brian Czerniecki, MD, PhD, chair of Moffitt’s Breast Oncology Department.
The dendritic cell vaccine is also being studied in patients with metastatic HER2-positive breast cancer.
The next step is to open a new phase 2 arm of the trial that will study the efficacy of the dendritic cell vaccine with HER2-targeted therapies in a chemotherapy-free regimen.
“We feel that this study data is very encouraging, and this could be the next step: that not all patients will need chemotherapy,” Han said. “This won’t apply to all patients, but for a selective group we can predict will have a greater response to this type of dedicated therapy.”
