Pegram suggested switching AI drugs to cope with bone pain. "For reasons we don't know, it sometimes helps," he said. "If that doesn't work, use tamoxifen instead."
Used when: The cancer is HER2-positive.
How it works: About 20 percent of women have a type of breast cancer cell that makes too much — or over expresses — protein called Human Epidermal growth factor Receptor 2 (HER2), which helps tumor cells grow. HER2-positive breast cancers tend to be more aggressive than other types of cancer, according to the American Cancer Society and are less responsive to hormone treatment. The drug Herceptin (trasatuzumab) reduces the risk of recurrence by targeting the receptors on the HER2-cell surface. It binds to the HER2 receptor and blocks the signals the cancer needs to grow. It can also stimulate immunity against the tumor, said Pegram, who helped develop the treatment that combines standard chemotherapies with Herceptin. "Antibodies can recruit infection infighting cells," he said. "They can release hostile substances that attack and kill the target," he said.
Given by infusion, every one to three weeks for a year, Herceptin is used in combination with chemotherapy for about a quarter of breast cancer patients. This combo has been shown to prolong survival in Stage 4 cancer that has spread throughout the body. It also reduces the risk of mortality by about a third when used in early stage breast cancer, said Pegram.
Side effects: Heart failure, nausea, vomiting, hot flashes and joint pain.
Used when: Researchers are working to develop vaccines that prevent breast cancer or are used after a diagnosis.
How they work: Several studies are looking at vaccines designed to teach the body how to respond to the HER2-based protein fragment so that it would recognize cancer when it recurs and attack it, said Elizabeth Mittendorf, a surgical oncologist at the University of Texas MD Anderson Cancer Center in Houston who specializes in breast cancer immunotherapy.
Data from two trials has shown that one type of a HER2-based vaccine triggered the desired immune response in women with an HER2-positive tumor. The vaccine is still at least five years away from being made widely available, said Mittendorf.
In addition to HER2 vaccines, some researchers are looking at genetically engineered vaccines that prompt the release of a substance to enhance the immune system response.
Others researchers are studying vaccines in combination with drugs. In one small preliminary study of 10 patients, researchers at Penn's Abramson Cancer Center showed a one-time infusion of the drug Zenapax (daclizumab) improved the survival of breast cancer patients given several doses of cancer vaccines by 30 percent, compared to those patients not taking daclizumab.
The combination of a vaccine and Femara increased survival when tested in mice. Mittendorf's research group is looking at vaccines in combination with Herceptin.
Despite an enormous amount of research, with rare exceptions, vaccines haven't yet been proven effective, said Pegram. Because cancer cells originate within the body, the immune system generally doesn't recognize them as foreign and won't mount an attack.
"In many cases, tumors have ways of outsmarting the human defense system and avoiding surveillance. The problem is just starting to be addressed," he said.