Data obtained at the University of Texas Southwestern Medical Center and funded by a grant from the Cancer Prevention Research Institute of Texas was presented at the American Association for Cancer Research this week in San Diego, California. The presenting author of the poster, Olivier Belzile, detailed the effects of bavituximab from Peregrine Pharmaceuticals, Inc. on non-small cell lung cancer in rats. Bavituximab is Peregrine’s lead immunotherapeutic antibody and is one of only a few first-in-class monoclonal antibodies from the biopharmaceutical company proposed to treat cancer. Specifically, bavituximab targets stressed, phosphatidylserine-expressing tumor vasculature and tumor cells, and it was hypothesized that bavituximab combined with intense irradiation would have “additive or synergistic activity” against lung tumors.
To test this hypothesis, the research team from UT Southwestern injected rats with human non-small cell lung cancer cells and monitored tumor growth. Rats were split into four groups three weeks after tumor implantation: untreated, radiation only, 2aG4 (rodent equivalent antibody to bavituximab) only, or radiation and 2aG4. After 184 days of treatment, the radiation+2aG4 group had a 100% survival rate and a 67% tumor eradication rate. In contrast, only 12.5% of untreated, 33% of 2aG4, and 43% of radiation rats survived, and these rats were tumor-free.
“Data from these studies show a very impressive survival improvement and tumor burden reduction when administering an animal equivalent of bavituximab with radiation therapy compared to radiation alone,” said Jeff T. Hutchins, Ph.D., vice president of preclinical research at Peregrine. “Importantly, the use of lower doses of stereotactic body radiation, a highly targeted therapeutic irradiation technique, demonstrates considerable therapeutic value in combination with bavituximab activity. Based on these results, we believe there is potential for more effective and less toxic combinations of stereotactic body radiation and investigational immunotherapies like bavituximab to work together as a potential treatment modality for patients with lung cancer.” Already, bavituximab is being evaluated in the SUNRISE pivotal phase III clinical trial for the treatment of non-small cell lung cancer.