Study that combined bevacizumab with chemotherapy yields disappointing results
The monoclonal antibody bevacizumab, when added to a standard chemotherapy treatment for mesothelioma, does not extend the lives of patients, according to a study conducted at nearly a dozen of the nation's top cancer centers.
Bevacizumab is an angiogenesis inhibitor that chokes off the supply of blood that tumors need to grow and proliferate. It works by blocking a chemical signal called vascular endothelial growth factor A, or VEGF-A, that stimulates the growth of new blood vessels. Marketed under the name Avastin, bevacizumab is licensed to treat various cancers, including colorectal, lung, kidney and ovarian, often in combination with other cancer drugs.
In a Phase II clinical trial that involved 11 U.S. cancer centers, clinicians gave bevacizumab or a placebo to 118 patients who were receiving a combination of gemcitabine and cisplatin, a common chemotherapy for mesothelioma. All of the patients had advanced malignant mesothelioma, but were physically active based on standard oncology criteria and exhibited no signs of thrombosis, bleeding or major blood vessel invasion.
The results showed no meaningful difference in the outcomes of the two study groups.
The median progression-free survival — the length of time after treatment that the cancer did not worsen — was about the same in both the bevacizumab and placebo groups: 6.9 months versus 6 months. Median overall survival was 15.6 for the bevacizumab group and 14.7 months for patients receiving the placebo. Partial response rates — the percentage of patients whose cancer shrunk — were also similar, 24.5 percent for bevacizumab versus 21.8 percent for placebo.
The results of the study, led by researchers at the University of Chicago Comprehensive Cancer Center, were published online by the Journal of Clinical Oncology.
Research in 2009 that combined bevacizumab with pemetrexed and cisplatin, another popular chemotherapy regimen for mesothelioma, yielded similarly disappointing results. In that study, which involved 43 patients with advanced mesothelioma at four cancer centers, researchers found that the addition of bevacizumab did not extend survival compared to pemetrexed-cisplatin alone.