January 3, 2017

Promising Clinical Activity for HER2-Targeted Vaccine in Early-Stage Breast Cancer

TAMPA, Fla -- January 3, 2017 -- A dendritic cell vaccine that targets the human epidermal growth factor receptor 2 (HER2) protein on breast cancer cells is safe and effectively stimulates the immune system leading to regression of early-stage breast cancer, according to a study published in the journal Clinical Cancer Research.

Researchers have previously shown that immune cells are less able to recognise and target cancer cells that express HER2 as breast cancer progresses into a more advanced and invasive stage. This suggests that strategies that can restimulate the immune system to recognise and target HER2 early during cancer development may be effective treatment options.

Researchers at the Moffitt Cancer Center, Tampa, Florida, previously developed a vaccine that helps the immune system recognise the HER2 protein on breast cancer cells. Their approach involves creating the vaccine from immune cells called dendritic cells that are harvested from each individual patient to create a personalised vaccine.

In order to determine if the HER2-dendritic cell vaccine is safe and effective, the researchers performed a clinical trial in 54 women who have HER2-expressing early-stage breast cancer. The dendritic cell vaccines were prepared by isolating dendritic cells from each patient’s blood and exposing them to fragments of the HER2 protein. Patients were injected with a dose of their personal dendritic cell vaccine once a week for 6 weeks into either a lymph node, the breast tumour, or into both sites.

The researchers report that the dendritic cell vaccines were well-tolerated and patients only experienced low-grade toxicities. The most common adverse events were fatigue, injection site reactions, and chills.

The vaccine was able to stimulate an immune response in the majority of the patients. Approximately 80% of evaluable patients had a detectable immune response in their peripheral blood and/or in their sentinel lymph node wherein their cancer is most likely to spread to first. Importantly, the immune responses among the patients were similar, regardless of the route of vaccine administration.

A total of 13 patients achieved a pathological complete response (pCR) and patients who had early non-invasive disease called ductal carcinoma in situ (DCIS) achieved a higher rate of pCR than patients who had early-stage invasive disease. Interestingly, patients who achieved a pCR had a higher immune response within their local sentinel lymph nodes.

“These results suggest that vaccines are more effective in DCIS, thereby warranting further evaluation in DCIS or other minimal disease settings, and the local regional sentinel lymph node may serve as a more meaningful immunologic endpoint,” said Brian J. Czerniecki, MD, Moffitt Cancer Center.

SOURCE: Moffitt Cancer Center

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