SAN ANTONIO — New drug combinations are helping women with early breast cancer. Using two drugs that more precisely target tumors doubled the number of women whose cancer disappeared compared to those who had only one of the drugs, doctors reported Friday.
However, another study added to the controversy over Avastin for breast cancer. Most women who received the drug for a few months before surgery fared no better than those who did not, it found.
The studies were presented Friday at the San Antonio Breast Cancer Symposium.
The good news study was the first test of Herceptin and Tykerb together for early-stage disease. They aim at a protein called HER-2 that is overproduced in about one-fourth of all breast cancers. Herceptin blocks the protein on the cell's surface; Tykerb does it inside the cell.
Dr. Jose Baselga, associate director of the Massachusetts General Hospital Cancer Center, led a study when he previously worked in Barcelona, Spain, that tested these drugs alone and in combination in 455 patients who also were given the chemotherapy drug paclitaxel.
The patients were treated for about four months before surgery to remove their tumors and for nine months afterward. Doctors have been testing drugs in advance of surgery to shrink tumors and make the operation less drastic, and to get an idea quickly if these drugs will help a patient.
Just over half of the women who received Herceptin and Tykerb were discovered to have no signs of invasive cancer when their surgeries were done, versus only 25 to 30 percent of those given just one of these drugs.
Tykerb had more side effects, mostly diarrhea. But the main side effect of combo treatment is to the wallet: Tykerb pills cost $5,000 to $6,000 per month. Herceptin costs more than $4,000 a month plus whatever doctors charge to infuse it.
"The possibility that we have here is to enhance the number of patients that are cured" and avoid more treatment down the line that might cost more, Baselga said.
However, Dr. Neil Spector of the Duke Cancer Institute said cost "is a real consideration."
Yet he called the results "really exciting" and said the future of cancer care is approaches like this that use targeted drugs well matched to patients' tumor profiles.
British-based GlaxoSmithKline PLC makes Tykerb; California-based Genentech, now part of the Swiss company Roche, makes Herceptin. Glaxo helped pay for the study.
A second study in Germany pitted the two drugs against each other in 600 women with early breast cancer also getting standard chemotherapy for six months before surgery. Herceptin won: 31 percent saw their tumors disappear versus 22 percent on Tykerb.
The Avastin study drew high interest because the Food and Drug Administration is considering revoking the drug's approval for breast cancer that has widely spread. Evidence suggests it does not meaningfully improve survival for advanced cases.
The new study tested it in more than 1,900 women with early breast cancer or large tumors that are not the type that Herceptin or Tykerb can help. All were given standard chemotherapy and half also got Avastin for several months before surgery. Tumors disappeared in nearly one in five women regardless of what treatment they got, said study leader Dr. Gunter von Minckwitz of the University of Frankfurt in Germany.
One group did benefit: women with "triple negative" cancers – those not fueled by estrogen, progesterone or the protein that Herceptin targets. In women with these hard-to-treat cancers, Avastin boosted by 40 percent the number whose tumors disappeared.
Four companies that make drugs used in the study paid for the research, and von Minckwitz has been a paid speaker for some of them.
Roche sells Avastin wholesale for $7,700 a month, but infusion charges push the tab to as much as $10,000.
The FDA approved Avastin for breast cancer in 2008 against the advice of outside experts. In July, an advisory panel voted 12-1 to recommend revoking its approval for widely spread breast cancer, and the agency has said it will decide by next Friday.
"There's a subgroup of women for whom I think it could be highly effective," but more studies are needed to figure out who they are, said Dr. Jennifer Litton, a breast cancer specialist at the University of Texas M.D. Anderson Cancer Center.
Dr. Sandra Horning, global development chief of cancer drugs for Roche and Genentech, said results may be better in several other studies under way, including one in women with triple-negative tumors. Nor does the new study affect the drug's current use in other cancers.
"We continue to believe Avastin is an important option for women," Horning said.
Cancer conference: http://www.sabcs.org