Inovio Pharmaceuticals, Inc. have announced that its SynCon® DNA vaccine containing multiple malaria antigens delivered via its CELLECTRA® electroporation device demonstrated strong and durable antibody and T-cell immune responses in small animals and non-human primates. With these strong preclinical results, Inovio plans to initiate a phase I/IIa clinical trial next year.
These results appear in the American Society for Microbiology’s peer-reviewed journal, Infection & Immunity, in a paper entitled: “Inducing humoral and cellular responses to multiple sporozoite and liver-stage malaria antigens using pDNA,” authored by Inovio researchers and collaborators.
The World Health Organization estimated that in 2010 there were more than 200 million cases of malaria and almost 700,000 deaths due to malaria infection, the majority affecting young children in Africa. To date, the most advanced malaria vaccine candidate RTS,S, an adjuvanted recombinant protein vaccine, has not shown substantial protection in the key trial age group of infants. Scientists believe that a more effective malaria vaccine should generate both strong antibody and potent T-cell immune responses.
In this study, Inovio researchers and collaborators designed a highly optimized DNA vaccine composed of four sporozoite and liver-stage malaria antigens using Inovio’s SynCon technology. These antigens were chosen because of their important role in the control or elimination of malaria infection. Delivered using Inovio’s CELLECTRA delivery system, this malaria vaccine generated robust and long-lasting T-cell responses in both mice and non-human primates. Moreover, these vaccine-produced T-cells exhibited the functional ability to kill and eliminate malaria-infected cells. Researchers also found vaccine-induced CD8+, or “killer T-cells,” in the liver, which is essential for rapid elimination of liver-stage malaria parasites. The Inovio DNA/electroporation platform has demonstrated in prior preclinical and human studies the ability to induce potent immune responses to multiple antigens; in this study, robust and sustained antibody responses to all four malaria antigens were observed, a strong indication for a preventive response in humans.
Inovio plans to initiate a phase I/IIa clinical trial in 2014 to test Inovio’s DNA vaccine and electroporation technology in approximately 30 individuals as part of a “challenge trial” involving controlled human malaria infection. Volunteers will be administered Inovio’s vaccine, then exposed to the malaria parasite through the bite of infected mosquitoes to see whether this approach prevents infection. If deemed successful, this trial would provide valuable information that may further the development of a vaccine against malaria and lead to larger efficacy studies in the field.
Dr. J. Joseph Kim, President and CEO of Inovio, said, “Published data from two clinical studies has demonstrated that Inovio’s products generated best-in-class T-cell immune responses. Using the same synthetic vaccine technology that produced clinical candidates against HPV, HIV, and influenza and achieved potent antibody and T-cell immune responses against these targets, we have now generated strong immunology data with our malaria vaccine in non-human primates. We are excited to advance toward the very important healthcare goal of conquering malaria.”
“Inducing humoral and cellular responses to multiple sporozoite and liver stage malaria antigens using pDNA” Infection & Immunity, Published ahead of print 29 July 2013, doi: 10.1128/IAI.00180-13
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