MedImmune, Inc. and Cerus Corporation have announced preclinical results demonstrating the effectiveness of a novel therapeutic vaccine technology in suppressing the growth of certain tumors.
These results will be presented today at the 95th Annual Meeting of the American Association for Cancer Research (AACR) in Orlando, Florida at 8:00 a.m. eastern time. The associated AACR poster is entitled "Recombinant Listeria monocytogenes-Based Immunotherapy Targeting the Receptor Tyrosine Kinase EphA2." "Previous research has indicated that we may be able to promote selective destruction of tumor cells while minimizing the damage to normal cells using EphA2 antibodies," said Peter Kiener, D.Phil., vice president, research at MedImmune. "These new data reveal that we also may one day apply new bacteria-mediated strategies for treating or preventing the many cancers that express the EphA2 protein, including breast and colon cancer." To evaluate the effects of a Listeria-mediated vaccine technology, MedImmune and Cerus scientists implanted mice with tumors and then treated them with Listeria strains that had been genetically engineered to trigger an immune response directed at the EphA2 protein. Protective immunization with Listeria-huEphA2 significantly suppressed tumor growth in this study and prolonged survival for treated mice. Importantly, 80 percent of the Listeria- huEphA2-treated mice survived for greater than 43 days following tumor implantation whereas untreated controls had a median survival time of approximately 20 days. "This research demonstrates the potential to develop potent therapeutic vaccines utilizing our proprietary Listeria vaccine platform in combination with cancer antigens such as EphA2," said Stephen T. Isaacs, president and chief executive officer, Cerus Corporation. "Our vaccine platform is designed to encourage the stimulation of the patient's immune system to selectively recognize and destroy tumor cells expressing the targeted antigen."