An important breakthrough for the treatment of ovarian cancer has been announced.  A Phase III clinical trial has shown that adding the antiangiogenic agent bevacizumab (Avastin) to standard chemotherapy, and then continuing treatment with a maintenance dose of Avastin, can significantly extend the time women with previously untreated advanced ovarian cancer live without their disease getting worse. Women who received the new combined treatment regimen had no worsening of their disease for 14.1 months, compared to 10.3 months for women who got standard therapy—this translates to a 28% reduction in the risk of cancer progression.

Continuing the Avastin as maintenance therapy appears to be important, since women who received Avastin plus chemotherapy but did not receive the maintenance Avastin did not experience a greater survival advantage. The results of this clinical trial were presented at the 46th Annual Meeting of the American Society of Clinical Oncology (ASCO), held June 4-8 in Chicago.

The study marked the first time that an antiangiogenic agent has been proven to improve outcomes for advanced ovarian cancer. It was also the first time a maintenance dosing approach involving any therapy has been outlined for this disease. Ongoing analysis of the trial data may offer insights into whether genetically defined subgroups of patients who benefited more than others, and point to the possibility of more individualized treatment for ovarian cancer in the future.

“Ovarian cancer remains one of the most deadly cancers in women, so this clinical advance is particularly welcome,” says Robert A. Burger, M.D., lead investigator on the trial and director of the Women’s Cancer Center at Fox Chase Cancer Center. “Before this, we could treat ovarian cancer patients only with surgery and chemotherapy involving relatively toxic agents. Now, we have a third type of more targeted therapy to offer these patients, potentially opening the way to even greater progress in years to come.”

According to the American Cancer Society, approximately 22,000 new cases of ovarian cancer will be diagnosed this year, and about 15,000 women will die from their disease. Ovarian cancer is the eighth most common cancer among women, excluding non-melanoma skin cancers. It ranks fifth in cancer deaths among women, accounting for more deaths than any other cancer of the female reproductive system.

The trial (GOG-0218) enrolled 1,873 previously untreated women with advanced disease from 336 sites in four countries (U.S., Canada, South Korea, and Japan). The women were randomly assigned to one of three treatment protocols: standard chemotherapy (carboplatin and paclitaxel) plus placebo, followed by placebo maintenance for up to 10 additional months; standard chemotherapy plus Avastin followed by placebo maintenance; or standard chemotherapy plus Avastin followed by Avastin maintenance. The type and frequency of Avastin-related side effects were similar to those seen in previous cancer studies involving the drug.