Avastin can stabilize tumors in ovarian cancer, studies find
Avastin can stabilize tumors in women suffering from advanced-stage ovarian cancer, extending the period before the disease worsens by more than 3.5 months, according to the results of two large, international clinical trials conducted by separate research teams.
The findings, published in Thursday’s edition of the New England Journal of Medicine, come less than a week after the European Commission approved Avastin for treating women newly diagnosed with advanced ovarian cancer. The drug, known generically as bevacizumab, has not yet been approved by the Food and Drug Administration to treat ovarian cancer in the U.S.
Though Avastin has not been shown to prolong the lives of women with ovarian cancer and does come with significant side effects, it offers some hope for treating what remains the deadliest of gynecologic cancers, researchers said.
Ovarian cancer affects an estimated 200,000 women worldwide and causes 125,000 deaths each year, including more than 15,000 in the U.S. The cancer is particularly difficult to treat because it usually found after it has already spread to other organs. Surgery can remove only some of the tumors, and the two chemotherapy drugs most commonly used aren’t very good at killing the cancer cells left behind.
But the study results suggest that treatment for ovarian cancer could improve for the first time in 15 years, said Dr. Robert Burger, a surgical oncologist at Fox Chase Cancer Center and lead author for one of the studies.
“I think we finally have a third component of treatment that works differently and that may greatly complement our therapeutics for ovarian cancers,” he said.
Avastin is a biological antibody that interferes with a growth factor that cancer cells need to grow new blood vessels. When used in concert with chemotherapy, the drug helps keep cancers that have metastasized from growing and spreading. The FDA has approved the drug for use in a number of different cancers, including non-small-cell lung, kidney, brain and colon cancer.
Most recently, its use in treating breast cancer has become a source of controversy, as the FDA last month withdrew its approval of Avastin for patients with advanced breast cancer because the modest benefits were not seen as outweighing the drug’s side effects. Physicians, however, can still prescribe Avastin off-label.
Burger’s team, known as the Gynecologic Oncology Group, looked at what’s called progression-free survival — the length of time before the cancer gets worse — in 1,873 women with newly diagnosed stage III and stage IV ovarian cancers, which typically have 5-year survival rates ranging from 18% to 45%. The investigators found that patients who received Avastin throughout their chemotherapy treatment experienced 14.1 months of progression-free survival, compared with the 10.3 months for patients who received standard chemotherapy plus a placebo. (Patients who received Avastin only during the initial treatments had 11.2 months of progression-free survival.)
The second study, by the International Collaboration on Ovarian Neoplasms, looked at 1,528 ovarian cancer patients and found a smaller difference in progression-free survival — 24.1 months for those who took Avastin versus 22.4 months for those who didn’t.
But when they focused on the 465 patients with the most advanced cancers, they found a bigger benefit — 14.5 months with standard therapy alone and 18.1 months with Avastin added. They also found that overall survival for these patients was better with Avastin, at 28.8 versus 36.6 months.
On the whole, however, the researchers said they would not able to say much about overall survival rates until the patients had been tracked for a few more years.
The studies documented some notable side effects from the drug, including an increased risk of hypertension and gastrointestinal wall disruption, when a hole develops in the gastrointestinal tract. But these problems did not affect patients’ quality of life, both studies found.
Avastin does not come cheap. The drug, made by Genentech Inc., can cost about $50,000 to $100,000 a year, which may be a lot to pay for just a few months more of remission, said Dr. Joanne Mortimer, director of the Women’s Cancers Program at the City of Hope Comprehensive Cancer Center in Duarte. Many insurance companies cover at least some of that cost.
“Is it worth it?” said Mortimer, who served on two of three FDA advisory panels that debated the use of Avastin for breast cancer. “These are positive studies, but are they meaningful differences?”
Though the answer for breast cancer was no, the answer for ovarian cancer may be different, she said. Drugs for breast cancer are held to a higher standard because much more is known about how to treat the disease. The bar is lower for ovarian cancer because the treatment options aren’t as good, Mortimer said.
Dr. Timothy Perren, a medical oncologist at Spire Leeds Hospital in Yorkshire, England, who led the second study, said the trials were promising steps that would “cement the place of Avastin in treating ovarian cancer.” But researchers from both groups noted that more work needed to be done to figure out which patients would benefit the most from the drug and the best way to administer it.
The studies were funded by the National Institutes of Health, the National Institute for Health Research in Britain, Genentech and its parent company, Roche.