Inovio’s COVID-19 Vaccine Suggests Overall Immune Responses in Phase I Trial


Biotech company Inovio released positive interim data from its Phase I clinical trial of INO-4800, its experimental vaccine against COVID-19.

INO-4800 is one of the experimental vaccines included in the U.S. government’s Operation Warp Speed that has a goal of having a vaccine available by January 2021. The vaccine was designed using the company’s proprietary DNA medicine platform. Inovio claims it is the only nucleic acid-based vaccine that is stable at room temperature for more than a year and doesn’t need to be frozen in transport or storage.

In the interim data in 40 healthy volunteers, 94% of the recipients demonstrated an overall immune response at Week 6 after two doses of the vaccine. At Week 8, the vaccine appeared to be both safe and well-tolerated with no serious adverse events. All of the adverse events were mild, grade 1 in severity. Most were redness at the injection site.


In addition, in preclinical studies in animals, the vaccine provided full protection against the virus replicating in the lungs of mice that were vaccinated, then dosed with the virus.

“Inovio would like to thank all of the trial participants and the investigator staff who have made this trial possible,” said J. Joseph Kim, president and chief executive officer of Inovio. “We are very encouraged by the positive interim safety and preliminary cellular and humoral immune response results to date as well as the inclusion of INO-4800 in Operation Warp Speed.”

Kim added, “We are also pleased that INO-4800 vaccination abrogated viral replication in the lungs of mice challenged with SARS-CoV-2. We look forward to urgently advancing INO-4800.”

The trial initially enrolled 40 healthy adults between the ages of 18 to 50 at two sites in the U.S. They received funding from the Coalition for Epidemic Preparedness Innovations (CEPI). The patients received either 1.0 mg or 2.0 mg of the vaccine four weeks apart. Each dose was given by way of Inovio’s CELLECTRA 2000 intradermal injection device. Then an independent Data Safety Monitoring Board reviewed the safety data.

Slightly puzzling, Inovio shares dropped 11.8% at the news. Although the data is positive, analysts and investors seem to think the company did not disclose enough information to be meaningful about the efficacy of the vaccine.

The key may be the company did not provide details about neutralizing antibodies, which would prevent infection by the virus.

Keith Speights, an analyst with The Motley Fool, wrote, “It even seemed that Inovio could be attempting to downplay the importance of neutralizing antibodies. In the company’s press release announcing the interim Phase I results for INO-4800, Inovio referenced two studies published earlier this year that found between 33% and 40% of individuals who recovered from COVID-19 had low levels of neutralizing antibodies.”

When Moderna released information about the interim Phase I data from its own COVID-19 vaccine, the company did provide at least some data about the number of patients that produced binding antibodies and neutralizing antibodies. That didn’t stop experts from criticizing the general lack of detail in the company’s data.

Kim, however, in an interview with the Philadelphia Inquirer, dismissed the stock drop. “We don’t pay a whole lot of attention to short-term stock movements,” he said. “This is really good data. We’re excited. It’s safe and very immunogenic and we look forward to advancing it.”

Inovio expects to begin a Phase II/III clinical trial of the vaccine this summer, pending approval from the U.S. Food and Drug Administration (FDA). One of the selling points of Inovio’s vaccine, should it make it to the market as an approved vaccine or under an Emergency Use Authorization, is that it can be shipped and stored at room temperature. When in the context of a global pandemic, this could simplify some of the supply chain logistics of delivering a vaccine to hundreds of millions, potentially billions of people around the world.

“While the pathophysiologic profile of SARS-CoV-2 is not completely understood, research and clinical studies suggest that both T-cell and antibody immune responses will be important for protection in both mild and serious infections,” said Kate Broderick, senior vice president of R&D at Inovio. “Leveraging our previous expertise in MERS with INO-4700, where we demonstrated significant antibody and cellular responses, the breadth and profile of the responses observed to date with INO-4800 targeting SARS-CoV-2 provide a promising read towards further development and addressing the existing public health threat.”

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