Based on data from a phase III trial showing a median overall survival benefit of 1.4 months, the U.S. Food and Drug Administration approved regorafenib (Stivarga; Bayer) for the treatment of metastatic colorectal cancer that progresses in spite of other therapies.
The U.S. Food and Drug Administration (FDA) has given a green light to Bayer to market the oral drug regorafenib (Stivarga) for the treatment of metastatic colorectal cancer that progresses in spite of other therapies. An inhibitor of multiple kinases that promote cancer growth, including vascular endothelial growth factor receptors 1, 2, and 3, regorafenib received an expedited review because patients with the disease have few treatment options.
FDA approval was based on a single international trial of 760 patients previously treated for metastatic colorectal cancer. Researchers randomly assigned patients to receive either regorafenib or a placebo, in addition to supportive care. The patients continued treatment until they could no longer tolerate it or their disease progressed.
Patients who were treated with regorafenib lived a median of 6.4 months compared with 5 months in patients who received the placebo. Patients taking the drug also experienced a median delay in tumor growth of 2 months compared with 1.7 months in those taking the placebo. Other drugs aren't much more effective. Approved by the FDA in August, the colorectal cancer drug ziv-aflibercept (Zaltrap; Sanofi/Regeneron) improved overall survival by just 1.5 months compared with placebo.
“The impact has been incremental, and we all wish that the benefit of these therapies would be greater,” says Charles Fuchs, MD, MPH, director of the gastrointestinal cancer center at Dana-Farber Cancer Institute in Boston, who was not an investigator for the trials of either drug. “But these studies were done in patients who had already failed multiple therapies.”
“It's incumbent upon us to come up with a much better strategy to develop and test drugs,” he adds.
For example, clinical trials of both drugs assessed safety and efficacy in heterogeneous patient cohorts. If researchers could find biomarkers that define patient populations more likely to respond to these agents, overall survival for those particular subgroups might be higher.
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