PLYMOUTH MEETING, Pa., July 30, 2020 /PRNewswire/ -- INOVIO (NASDAQ:INO), a biotechnology company focused on rapidly bringing to market precisely designed DNA medicines to treat and protect people from infectious diseases and cancer, today announced that its COVID-19 DNA vaccine INO-4800 targeting SARS-CoV-2 was effective in protecting non-human primates (NHPs; specifically rhesus macaques) from live virus challenge 13 weeks after the last vaccination. These protective results were mediated by memory T and B cell immune responses from INO-4800 vaccination.
These results, submitted to a peer-reviewed journal and also published today on the non-peer reviewed online preprint site bioRxiv, demonstrate that INO-4800 reduced viral load in both the lower lungs and nasal passages in macaques that received two doses of INO-4800 (1 mg) four weeks apart and then were challenged with live virus 13 weeks after the second dose (study week 17). The reduced viral loads following exposure to SARS-CoV-2 infection at this timeframe demonstrate an important durable impact mediated by INO-4800. This is the first time a vaccine protection in non-human primates was reported from memory immune responses as previously reported monkey vaccine challenge studies were conducted at the time near their peak immune responses (1-4 weeks from their last vaccination).
INO-4800-treated animals demonstrated seroconversion after a single vaccination, with protective neutralizing antibodies and T cells lasting in their blood more than four months after the initial dose. The antibody levels were similar to or greater than those seen in patients who have recovered from COVID-19, the infection caused by SARS-CoV-2, and the T cell responses were significantly higher than those from convalescent patients.
Dr. J. Joseph Kim, President and Chief Executive Officer of INOVIO, said, "All other previously reported NHP vaccine protection studies actually challenged the animals at the peak of their immune response. Our study demonstrates that INO-4800 could provide protection in a more real-world setting, where vaccine-generated memory immune responses protected NHPs for more than 3 months (13 weeks) from the last vaccination. Given the importance of protective antibody and T cell responses, this study gives us more confidence as we continue to advance INO-4800 in the clinic. We believe INO-4800 holds significant potential to help address this global public health crisis."
B cells are responsible for producing the antibodies that recognize SARS-CoV-2, while T cells play a role in killing the virally infected cells as well as supporting the B cell response. The published data support that immunization with INO-4800 limits active viral replication and has the potential to reduce severity of disease, as well as reduced viral shedding in the nasal cavity. In the study, researchers assessed the ability of INO-4800 to induce acute and memory T cell and B cell immune responses, including neutralizing antibody responses against both early virus as well as now-dominant G614 mutant variants. To INOVIO's knowledge, this is the first report of vaccine-induced responses driving immunity against G614 variants. A strong anamnestic or memory T and B cell responses were demonstrated following challenge with the live virus.
"As we eagerly anticipate initiating a Phase 2/3 efficacy trials this summer, an animal challenge is currently the closest thing we have to testing a vaccine's efficacy when confronting a live virus. We are very encouraged with the duration of protection that INO-4800 demonstrated in this NHP study and look forward to reassessing its impact on durability of response at 12 months out from our other ongoing non-human primate and animal challenge studies," said Dr. Kate Broderick, Ph.D., INOVIO's Senior Vice President, Research & Development.
"In addition to safety and efficacy, it is essential that any vaccine targeting SARS-CoV-2 generates a relevant durability of response," Dr. Broderick added. "A vaccine that only provides protection for a very short period of time is not going to realistically solve the problem of this pandemic."
A separate NHP study evaluating the durability of INO-4800 at 12 months after vaccination is currently under way. INO-4800 also has been selected by U.S. Operation Warp Speed for its COVID-19 non-human primate challenge study.
In May, the peer-reviewed journal Nature Communications published an INOVIO study ("Immunogenicity of a DNA vaccine candidate for COVID-19") showing that vaccination with INO-4800 generated robust binding and neutralizing antibody and T cell responses in mice and guinea pigs. The study was funded by a grant from the Coalition for Epidemic Preparedness Innovations (CEPI).