Milder cancer remedies may lie with antibodies

SAN ANTONIO, Texas — New breast cancer findings support the idea that patients in the future may be treated with combinations of new, targeted medications that are kinder and gentler than conventional cancer drugs, researchers reported Friday.

In one small study, women with advanced cancer that had already metastasized, or spread, to other parts of the body were given two synthetic antibodies, Herceptin and Avastin, instead of the usual chemotherapy. More than half saw their tumors shrink dramatically, according to a paper presented at the annual San Antonio Breast Cancer Symposium.

"The response rate was impressive for patients with metastatic breast cancer," said Dr. Mark Pegram of UCLA. "And they didn't lose their hair or develop anemia or suffer from nausea or vomiting."

Pegram said that although most of the side effects were mild, investigators were carefully monitoring cardiac safety after one patient developed heart problems. "It's not clear whether the heart problem is related to this treatment," he said, "but we're being careful."

If the research proves successful, the next step likely will be to test the drug combination in earlier stages of breast cancer. Pegram said the approach could "open the door to all-biological therapies and allow us to get rid of chemo some day."

Herceptin and Avastin are considered biological agents because they are antibodies to disease-causing proteins. Herceptin targets HER2, a protein that encourages cells to multiply out of control. Avastin inhibits VEGF, which stimulates the formation of blood vessels. When those two targets are shut down, tumors that depend on them cannot continue to grow.

"Combining different biological therapies is the wave of the future," said Dr. Harris Spiridonidis of Columbus, Ohio, who is not associated with the study. But he cautioned that the new agents "are not innocent."

With targeted therapies, which home in on cancer cells and spare most normal cells, "side effects are not common," he said, "but they can be devastating. Nausea passes after a few months. A stroke lasts for the rest of your life."

Pegram's trial has included only 42 patients to date, so it's too early to draw firm conclusions. But it was just one of several studies presented at the influential four-day symposium that suggest a trend toward less-toxic treatment options.