Results from two Phase III clinical trials suggest that the addition of the targeted therapy Avastin® (bevacizumab) to chemotherapy delays the progression of advanced ovarian cancer but may not improve overall survival. These results were published in the New England Journal of Medicine.
Each year in the United States, roughly 22,000 women are diagnosed with ovarian cancer and more than 15,000 die of the disease. Treatment for ovarian cancer commonly involves surgery and/or chemotherapy, but outcomes for women diagnosed with advanced disease remain poor, and researchers continue to evaluate new approaches to treatment.
Avastin is a targeted therapy that blocks a protein known as VEGF. VEGF plays a key role in the development of new blood vessels. By blocking VEGF, Avastin deprives the cancer of nutrients and oxygen and inhibits its growth. Currently, Avastin is used for the treatment of selected patients with lung cancer, colorectal cancer, kidney cancer, or glioblastoma.
The role of Avastin in ovarian cancer was evaluated in two Phase III clinical trials that were recently published in the New England Journal of Medicine. The first study enrolled 1873 women with newly diagnosed Stage III or Stage IV ovarian cancer. After surgery, women were assigned to one of three treatment groups: 1) chemotherapy alone; 2) chemotherapy plus Avastin; and 3) chemotherapy plus Avastin followed by up to 10 months of additional treatment with Avastin alone.
- Avastin delayed cancer progression: survival without cancer progression was 10.3 months among women treated with chemotherapy alone, 11.2 months among women treated with chemotherapy and Avastin, and 14.1 months among women treated with chemotherapy and Avastin followed by additional Avastin.
- Overall survival was similar in the three study groups.
- Side effects that were more common in the Avastin groups included high-blood pressure that required treatment and gastrointestinal perforation.
In a second study, researchers evaluated Avastin among 1,528 women with high-risk or advanced epithelial ovarian, primary peritoneal, or fallopian tube cancer. Study participants were treated with chemotherapy with or without Avastin. Women in the Avastin group continued Avastin treatment after chemotherapy was completed.
- The addition of Avastin delayed cancer progression: survival without cancer progression was 21.8 months among women treated with Avastin and chemotherapy, compared with 20.3 months among women treated with chemotherapy alone.
- The benefit of Avastin appeared to be greater for the subset of women at high risk of progression.
- Final information about overall survival is not yet available.
Taken together, these two studies suggest that Avastin given during chemotherapy and for several months afterwards delays the progression of ovarian cancer compared with chemotherapy alone. Avastin increases side effects, however, and may not improve overall survival. Additional research may clarify whether certain subgroups of ovarian cancer patients are more likely than others to benefit from Avastin.
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