Yet the relative risk compared to placebo was almost five times as high in Avastin patients. No differences emerged between high and low doses of the drug.
By contrast, some 25 percent to 30 percent of patients taking Avastin develop high blood pressure, 5 percent of them severe hypertension, Abraham said. And about 4 percent to 5 percent develop blood clots, he added.
"From the heart failure standpoint, Avastin is certainly no worse and in many instances better than some other chemotherapy agents that are used to treat cancer in general or breast cancer in particular," Abraham said. "But if you look at totality of data, hypertension, severe hypertension and thromboembolic [blood-clotting] events, there seems to be overall increase in cardiac deaths in these patients. When you take all of that together, it really raises the red flag."
The issue of harm vs. benefit weighs heavily on the minds of cancer experts, they added.
"When we have drugs that have small values, which is what Avastin is in the therapeutic setting, we really better be sure that these drugs are helping our patients and not doing some harm," said Dr. Jay Brooks, chairman of hematology/oncology with Ochsner Health System in Baton Rouge, La.
"Unfortunately, Avastin has proved to be not as good as we thought it would be," he added. "It was put on the market on accelerated approval and when we do things quickly sometimes, when there's a huge push to get it out to the public, sometimes it backfires."
Avastin's approval for treating breast cancer in 2008 was based on one clinical trial in patients with metastatic HER2-negative breast cancer that found a benefit in terms of cancer recurrence -- but not overall survival -- and was contingent on further data to confirm the results. Follow-up studies failed to confirm a survival benefit, which led to t
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