Here's the ASCO summary:
New Agent in Breast Cancer Research
The first therapy engineered to target a specific protein defect underlying the malignant progression of cancer has has sailed through phase III clinical testing. Herceptin is awaiting approval as a Fast Track Product by the U.S. Food and Drug Administration, Dennis Slamon, MD, reported Sunday.
Herceptin was tested in a phase III investigational trial of 469 women with tumors that over-expressed HER-2. The trial found a 53% increase in tumor response rate among women with metastatic breast cancer treated with Herceptin plus chemotherapy compared to those treated with chemotherapy alone, reported Dr. Slamon, vice-chair of research, UCLA Department of Medicine. Moreover, median time to disease progression was increased 65% among the Herceptin group. None of the women had received previous chemotherapy for their metastatic disease.
Two of the study participants remain disease-free five and six years after initiation of Herceptin therapy, Dr. Slamon reported. One has needed no further therapy after an initial 18-week course of Herceptin plus chemotherapy. The other continues to receive Herceptin.
Incidence of cardiac dysfunction was higher among patients receiving Herceptin and anthracyclines. However, Dr. Slamon reported that the dysfunction was managed with medication in most cases.
"We have a new agent that is effective," said Dr. Slamon, "That we were able to take this from the lab to the clinic in relatively short order is what has everyone excited."
The HER-2 growth factor receptor was first identified in 1985. Herceptin was submitted for FDA approval at the beginning of the month. Dr. Slamon predicted that Herceptin will be clinically available by the end of the year, and perhaps within a few months.
For now, a National Cancer Institute lottery system makes the drug available to about 100 women per quarter with metastatic disease who have failed two previous treatment regimens.
Nearly a third of women with breast cancer have tumors that over-express HER-2. The acquired gene aberration is associated with more rapid cancer progression and shortened survival.
"Women with HER-2-negative and HER-2-positive breast cancers are different than women with other breast cancers, and should be considered differently," Dr. Slamon said at a morning press conference sponsored by ASCO, "Breast Cancer Treatment Advances."
The success of Herceptin "proves the paradigm that if we understand what's broken in breast cancer, we can target that," he stressed.
Other speakers at the press conference echoed Dr. Slamon's enthusiasm. "I think this is the first step into the future, taking us from poisons to specific anti-cancer therapies," said Craig Henderson, MD, UCSF. "This is science at its best and most elegant."
"This is a critical point in translational research, and is only the tip of the iceberg," commented Lori J. Goldstein, MD, director, Breast Evaluation Center, Fox Chase Cancer Center.
Predicted Laura Hutchins, MD, Arkansas Cancer Research Center: "It's the beginning of a tidal wave. I hope the other [investigational treatments] now in the pipeline turn out to be as successful as this one."
Sounding a note of caution was Eric Winer, MD, associate professor, Dana Farber Cancer Institute, Boston. While acknowledging that Herceptin provides new hope, he emphasized the importance of not raising false hopes among desperate patients. |
