AVASTIN's MECHANISM OF ACTION IS NOT CLEAR

Study suggests Avastin, similar drugs may not halt tumor growth in patients with deadly form of brain cancer.
Bloomberg News (3/31, Larkin) reports that "Avastin [bevacizumab] and similar drugs being tested on the most deadly form of brain cancer may not halt tumor growth," according to a study appearing in the Journal of Clinical Oncology. Researchers at Harvard Medical School "induced brain tumors in mice and treated them with an experimental AstraZeneca Plc drug," cediranib, "that works the same way as Avastin." They found that "while the therapy prolongs survival by reducing swelling in the brain...it doesn't usually shrink tumors," and "cancer progression didn't slow." Meanwhile, Roche's Genentech unit is expected to "ask a US panel tomorrow to expand approval of Avastin based on preliminary data supporting a benefit for some people with glioblastoma." But, FDA regulators "questioned last week whether brain scans used for Genentech's analysis were sufficient to support approval before a large, randomized study is conducted."