U.S. health regulators are questioning whether Avastin is really an effective treatment for breast cancer. A Food & Drug Administration (FDA) advisory panel is scheduled to discuss Avastin tomorrow.
Avastin was the first approved therapy designed to inhibit angiogenesis, the process by which new blood vessels develop and carry vital nutrients to a tumor. Avastin was approved by the Food & Drug Administration (FDA) in 2004 to treat metastatic colon cancer, and in 2006, the agency approved it as a treatment for non-small cell lung cancer. In 2008, the FDA also approved Avastin as a metastatic breast cancer treatment in combination with a chemotherapy drug called paclitaxel, and in May 2009, it was approved to treat glioblastoma multiforme, an incurable brain cancer.
According to The Wall Street Journal, Avastin’s breast cancer indication was granted under an accelerated process that is based on initial positive studies. Companies then have to submit additional data to gain full approval. The Avastin approval was granted even though an FDA advisory panel had earlier voted 5-4 against it, the Journal said.
The FDA approval of Avastin for breast cancer was based on a study that didn’t show a statistically significant increase in overall survival. According to the Journal, the study found that patients treated with Avastin and paclitaxel added five-and-a-half months to median progression-free survive.
Roche, at the FDA’s request, then conducted two additional studies and submitted them to the FDA for full approval of Avastin. According to materials posted on the FDA’s Web site in advance of tomorrow’s meeting, those studies “failed to confirm the magnitude” of the benefit seen in the first study that supported Avastin’s approval. In one, the Journal said women treated with Avastin lived less than a month longer without their disease progressing compared with those who did not receive the drug. The other study showed a difference of no more than 2.9 month.
The materials posted on the FDA Web site also raise concerns about Avastin’s side effects, including bleeding, the Journal said.
According to The Wall Street Journal report, the FDA could ultimately decide to rescind the breast-cancer approval for Avastin, although it has not said specifically that it is considering that option.
Avastin has long been a subject of safety concerns. It has been linked to a higher risk of blood clots in the veins. And in December 2008, its maker reported that some Avastin patients had experienced eye inflammation when it was used off-label to treat an eye condition.
This past fall, an Avastin trial was halted after six patients developed clinical congestive heart failure. The late-stage trial, known as E5103, was testing Avastin in combination with chemotherapy for treatment of early-stage breast cancer. The trial was one of eight studying Avastin as a treatment for preventing relapse after surgery, known as adjuvant therapy.
Five of the six cases of congestive heart failure were “resolved” after the patients stopped taking both Avastin and the chemotherapy treatment. No information was available at the time the trial was halted for the sixth patient, but none of those who developed the disorder had died.