264. In Vivo DNA-Monoclonal Antibody (DMAb) Gene Delivery Protects Against Lethal Bacterial and Viral Challenges in Mice

Therapeutic monoclonal antibodies (mAb) are approved for treatment of several diseases including primary immunodeficiencies, cancer, asthma, and graft transplantation. Yet, only 2 mAbs are approved for administration against infectious diseases: palivizumab (respiratory syncytial virus) and raxibacumab (inhalational anthrax). Numerous protective mAbs targeting recurring and emerging bacterial and viral pathogens have been isolated, however, the high dosage (mg/kg) and associated cost of mAb manufacturing are significant hurdles for routine therapeutic delivery. Recently we have described the development of DNA vector-encoded monoclonal antibodies (DMAbs), as a possible alternative technology. This delivery targets skeletal muscle for invivo transfection to transiently produce and secrete mAb. By optimizing gene design protective levels of antibody are produced in vivo by this technology. We show that expression can last a period of weeks. These designed DMAb formulations encoding the mAb heavy and light chain genes are delivered in vivo by intramuscular injection followed by electroporation (IM-EP). Several DMAbs were developed targeting antimicrobial resistant bacteria, a serious global health concern. Additionally, we also designed DMAbs against a range of viral infections including frequent, emerging, and neglected tropical diseases. Through a series of sequence and formulation optimizations, we are able to achieve serum levels u003e5ug/mL and as high as 100ug/mL, depending on the DMAb. DMAb serum levels match the protective trough level range of their purified mAb counterparts and perform on par in functional assays (e.g. killing assays, neutralization). DMAb candidates are protective against bacterial and viral challenges in mice, illustrating functionality in vivo. Data from the challenge studies will be presented. Ongoing studies are investigating DMAb gene delivery in larger animal models including rabbits, guinea pigs, and non-human primates. DNA-delivered mAbs is a flexible platform that transforms mAb delivery, allowing for repeat administration, significantly lower production costs, and expands the utility of DNA vector technology for therapeutic gene therapy. This approach may have benefit for routine DMAb gene delivery to prevent nosocomial and community-acquired infections and can be rapidly deployed during an infectious disease outbreak.