Genentech Inc. said Tuesday that its Avastin cancer drug had failed to meet its primary goal of prolonging survival in a mid-stage trial of patients with metastatic colorectal cancer, but the company still expects U.S. approval of the drug next year.
Genentech, which in September asked U.S. regulators to approve Avastin as a first-line treatment for metastatic colorectal cancer in combination with chemotherapy, said it expected approval by the end of the first quarter of 2004 despite Tuesday's setback.
The biotech firm, based in South San Francisco, said the Phase II trial involved 209 patients who had not been previously treated for metastatic colorectal cancer, meaning tumors that have spread to other parts of the body. They took Avastin along with commonly used chemotherapy drugs 5-FU and Leucovorin.
Although patients taking the combination treatment saw a 29% improvement in overall survival, compared with those who took 5-FU and Leucovorin alone, Genentech said the increase was not statistically significant.
The study also showed that patients taking Avastin, on average, took 67% longer to develop a worsening of their condition -- a result that was highly statistically significant, although it was not a primary goal of the study.
The company's U.S. marketing application for Avastin was based on a separate 900-patient Phase III trial in which the drug also was used in combination with chemotherapy. The combo therapy prolonged median survival of patients about five months, or more than 30% longer than patients treated with chemotherapy alone.
The drug blocks a protein called vascular endothelial growth factor that promotes the growth of blood vessels to tumors.
Bear Stearns analyst Hayley Xuereb said patients in the successful Phase III trial also had taken Avastin in combination with 5-FU and Leucovorin, as well as a very toxic third chemotherapy drug called Irinotecan that was not used in the smaller Phase II trial.
She said the failed trial's results should not hurt Avastin's chances of approval because they were independent of the data being submitted to the FDA. Xuereb said Avastin performed as well as expected when used with all three chemotherapy drugs in the larger trial.
The trial results were released after the stock market closed. Genentech shares subsequently fell to $83 in after-hours trading, down from a close of $84.37, off 72 cents, on the New York Stock Exchange.