A very small study looked at an experimental treatment for HER2-positive breast cancers. This experimental treatment, a vaccine, isn't available yet. Still, the results do seem promising as a way to treat HER2-positive breast cancer in the future.
The experimental vaccine is called NeuVax. Researchers gave the vaccine to 163 women who had been diagnosed with HER2-positive breast cancer. About 2.5 years after receiving the vaccine, the number of women who died from breast cancer was 50% lower compared to a group of women diagnosed with HER2-positive breast cancer who didn't receive the vaccine. The vaccine is given once a month as an injection under the skin.
HER2-positive breast cancers make too much of the HER2 gene or HER2 protein. HER2-positive cancers:
- tend to grow faster
- are harder to treat
- are more likely to come back
compared to breast cancers that are HER2-negative. About 25% to 30% of all breast cancers are HER2-positive. Herceptin (chemical name: trastuzumab) and Tykerb (chemical name: lapatinib) are targeted therapy medicines that treat HER2-positive advanced breast cancers. Herceptin also is used to treat HER2-positive early-stage breast cancer after surgery to reduce the risk of the cancer coming back.
Your immune system helps keep you healthy by preventing and fighting infections. Your immune system also plays a role in preventing and fighting cancer. In a sense, vaccines rev up your immune system so it's better at protecting you against disease. The NeuVax vaccine tells the immune system to target breast cancer cells with HER2 protein.
Because the NeuVax vaccine targets the HER2 protein, the researchers thought that cancers that made a lot of HER2 protein would be most affected by the vaccine. (Cancers classified as HER2-positive can have a range of HER2 protein levels, but all are higher than cancers classified as HER2-negative.) But the results showed that even HER2-positive cancers with lower HER2 protein levels were affected by the vaccine, which is good news. None of the women diagnosed with HER2-positive breast cancers with lower HER2 protein levels who received the NeuVax vaccine died during the 2.5 years after receiving the vaccine. The women diagnosed with HER2-positive breast cancers with lower HER2 protein levels who received the NeuVax vaccine also had lower rates of the cancer coming back.
Because this study was so small, none of the results were statistically significant, which means they could have happened by chance. So we don't know if the NeuVax vaccine will really be an effective treatment for HER2-positive breast cancer. The results are very promising, but much more research is needed before doctors will know whether they can confidently and safely use this treatment.
If you've been diagnosed with breast cancer and think you might be interested in participating in a clinical research trial on a new treatment approach, such as NeuVax, talk to your doctor about whether any studies make sense for your unique situation.
And stay tuned to breastcancer.org for the latest updates on research that may lead to more effective ways to treat breast cancer.