Breast Cancer Vaccine Cuts Death Risk

Breast Cancer Vaccine Cut Death Risk for Patients (Update1)

By Luke Timmerman

April 13 (Bloomberg) -- An experimental treatment to stimulate the immune system against breast cancer appeared to cut the risk of death in half for women with a gene mutation in a small clinical trial conducted by the U.S. military.

The vaccine, made of a protein snippet, was designed to mimic the HER2 protein that raises the risk of tumor growth and death, and train the immune system to fight it. A study of women with the type of breast cancer fueled by excess HER2 proteins found the death rate dropped by half after 30 months for those on the vaccine, though the finding may have been due to chance, scientists said today at a cancer research meeting.

About one-fourth of breast cancer patients have the gene mutation that leads to excess HER2 proteins, researchers said. Those patients are eligible to take Genentech Inc.'s Herceptin. In a subgroup of women with lower levels of HER2, who aren't candidates for Herceptin, the vaccine also appeared to cut the risk of death, though that also may have been due to chance, researchers said. If proven in further trials, the vaccine could offer a new option to keep cancer from coming back.

``This is a potential way to immunize patients to lower the risk of recurrence,'' said Linda Benavides, a resident in general surgery at Brooke Army Medical Center at Fort Sam Houston in San Antonio, in an interview. Benavides was the study's lead author.

Based on the results, the vaccine was licensed from the U.S. military to Apthera Inc., a closely held biotechnology company in Scottsdale, Arizona. The product, now called NeuVax, is being prepared for the last stage of clinical trials, which intend to enroll 700 to 1,000 patients, Benavides said. The study plans to concentrate on women who aren't eligible for Herceptin, she said.

About 182,000 women in the U.S. will be diagnosed with breast cancer this year, according to the Atlanta-based American Cancer Society.

The findings were presented at the American Association for Cancer Research meeting in San Diego.

The results weren't completely consistent. Researchers found that among patients with high amounts of HER2 proteins, the relapse rate after 30 months was similar for those on the vaccine and those who didn't get treatment. Even though their cancer came back, patients on the vaccine appeared to have the 50 percent lower death rate, researchers said.

The vaccine also appeared to be effective among women with lower amounts of HER2 protein in their tumors, who aren't eligible for Herceptin, Benavides said. None of the women in that group on the vaccine died, while 6.8 percent of women died if they didn't get the vaccine, Benavides said. The difference may also have been due to statistical chance, she said.

It's possible the vaccine may work for women with lower amounts of HER2 because their immune systems aren't fully sensitized to detect the proteins already, Benavides said.

``The difficulty in interpreting the data is that patients with lower amounts of HER2 have a better prognosis to begin with,'' said William Hait, president of the American Association for Cancer Research and senior vice president for worldwide hematology and oncology research for Johnson & Johnson. ``I'm cautiously optimistic.''

The study was conducted among 163 female active-duty soldiers, spouses of soldiers and retirees with early stage breast cancer, Benavides said. They had standard surgery to remove their tumors, followed by chemotherapy and radiation to keep it from coming back, she said.

Herceptin generated $1.29 billion in U.S. sales in 2007, Genentech said. It's the company's third-biggest product behind Avastin and Rituxan.

Source: Bloomberg.com