The blockbuster cancer drug Avastin extends progression-free survival by 39 percent in ovarian cancer patients, a significant improvement in a cancer that has proved extremely difficult to treat.
Some oncologists are already using Avastin — which is widely and successfully used to treat lung, colon and breast tumors — to treat ovarian cancer that has recurred, but such use has never been formally studied. The new study, reported Sunday at a Chicago meeting of the American Society of Clinical Oncology, is also the first to use the drug as first-line therapy for ovarian cancer.
Ovarian cancer is the eighth-most common cancer among American women, striking an estimated 22,000 each year, and the fifth-most deadly, killing 15,000 a year. Conventional chemotherapy uses the powerful drugs carboplatin and paclitaxel, which can have severe side effects.
Avastin, in contrast, is targeted at a naturally occurring protein called vascular endothelial growth factor, which is overproduced in many cancers and stimulates the growth of new blood vessels that nourish the tumor. That targeting means it has fewer potential side effects and thus represents a major improvement in therapy for ovarian cancer, said Dr. Robert A. Burger of the Fox Chase Cancer Center in Philadelphia, who led the new study.
Burger and his colleagues studied 1,873 women with previously untreated ovarian cancer that had metastasized to the stomach and other organs. A third received conventional chemotherapy plus Avastin at the time of chemotherapy and in maintenance doses throughout the followup; a third received conventional chemotherapy plus Avastin and maintenance doses of a placebo; and a third received only conventional chemotherapy plus placebos.
Burger reported that during the 17 months of followup, conventional chemotherapy held the women's tumors in check for 10.3 months before they started progressing again, while chemotherapy plus Avastin and maintenance doses increased that period to 14.1 months. Using Avastin during the initial chemotherapy period without maintenance doses provided no statistically significant increase in progression-free survival. The study is ongoing, so the researchers do not know how the drug affected overall survival.
The principal side effects were increases in blood pressure and gastrointestinal problems. All those side effects are similar to those observed in treating other types of cancer.
Genentech, a Roche subsidiary that developed the drug, said it would apply to the Food and Drug Administration for permission to market it against ovarian cancer.