Vaccinating Against HER2 Reappearance

HER2 breast cancer responds to AE37 peptide vaccine being investigated

(RxWiki News) Breast cancers that have high levels of HER2 are particularly aggressive. Not only do they grow rapidly, but they tend to return after treatment. A vaccine currently being investigated appears to be effective in preventing this reappearing act.

A vaccine known as AE37 has been shown to curb the recurrence of breast cancers that contain various levels of human epidermal growth factor receptor 2 (HER2).

"Ask your oncologist about vaccine therapies."

Researchers at The University of Texas MD Anderson Cancer Center conducted the study that finds AE37 makes the immune system see HER2 as an enemy that needs to be attacked and crushed.

HER2 promotes breast tumor growth and appears at some level in 75-80 percent of breast cancers.

"The vaccine educates the immune system to recognize HER2 as an invader," said Elizabeth Mittendorf, MD, assistant professor in the Department of Surgical Oncology at MD Anderson and the national principal investigator of the trial.

"By introducing it into women who have had breast cancer, our goal is to instruct the immune system to immediately recognize any recurring cancer cells and orchestrate an attack," Dr. Mittendorf said.

To help the immune system better recognize AE37, researchers combined the vaccine with an immune stimulant known as granulocyte/macrophage colony stimulating factor (GM-CSF). 

The Phase II randomized clinical trial involved 201 disease-free breast cancer patients. Just over half (103) were given the vaccine after active treatment ended (adjuvantly), along with GM-CSF. The remaining 98 received only GM-CSF. 

Patients who were given the vaccine had a recurrence rate of 10.3 percent, while those who didn't receive the therapy, had an 18 percent rate at a median (right in the middle) follow-up of 22 months. This calculates to a 43 percent decreased recurrence risk.

Short-term side effects were modest and included redness at the injection site, flu-like symptoms and bone pain.

"These results using the AE37 vaccine to decrease breast cancer recurrence are impressive," Patrick D. Maguire, MD, a radiation oncologist in North Carolina, told dailyRx.

The vaccine is given as an injection, like an ordinary shot. This "off the shelf" design makes it easier to produce, distribute and give to patients than other currently available cancer vaccines, which require a complicated and expensive process to administer.

"There is high potential for this 'off the shelf' treatment vaccine targeted at immune recognition of HER2 to be practice changing. Hopefully its use will translate into significant survival improvements for patients with breast cancer," said Dr. Maguire, who is the author of When Cancer Hits Home: An Empowered Patient is the Best Weapon Against Cancer. 

Dr. Mittendorf adds, "The vaccine appears to prevent recurrence and works in women with any level of HER2 expression. Further, the findings draw parallels to other vaccines we now have advanced to later phase trials." 

MD Anderson has three different types of HER2-based peptide vaccines that are currently being tested.

Findings from this research will be presented at the upcoming American Society of Clinical Oncology (ASCO) conference. All research is considered preliminary before it's published in a peer-reviewed journal.

The trial was funded in part by Antigen Express, the company that licenses the vaccine technology. Based on this study, the company plans to apply for a special protocol assessment from the US Food and Drug Administration to continue Phase III research needed on the vaccine.

Review Date: 
May 22, 2012