Inovio hopeful about potential MERS vaccine

BLUE BELL, Pa.—If history teaches us anything in the life sciences, it’s that there’s always a more vicious pathogen around the corner. Several years ago, the SARS virus made the news after infecting some 8,000 people—now, a similar virus called Middle East Respiratory Syndrome coronavirus (MERS), apparently less contagious but far more lethal, has begun to catch some attention.

Fortunately, Inovio Pharmaceuticals Inc. already has the disease on its radar and has a preclinical candidate vaccine using the company’s SynCon vaccine platform.

There is currently no vaccine for MERS, which was first identified in 2012 in Saudi Arabia and has resulted in 153 known infections since then, with 42 percent of those cases being fatal, compared to the 10-percent fatality rate of SARS.

In Inovio’s preclinical study, DNA vaccine constructs targeting multiple MERS antigens were generated using the SynCon platform, with that SynCon vaccine subsequently administered via Inovio’s CELLECTRA electroporation-based delivery technology. According to the company, the vaccine constructs were observed to induce strong neutralizing antibodies and broad CD8+ T cells in mice.

These findings are vital, the company said, “given the importance of neutralizing antibodies in preventing infection and the role T cells play in clearing infection by killing cells that harbor the virus.”

“Our SynCon platform has again generated a synthetic vaccine candidate that shows promise for providing a treatment where there is none,” said Dr. J. Joseph Kim, Inovio’s president and CEO in a news release. “With human data showing the powerful killing effect of T cells generated by our vaccine for HIV and our therapy for HPV-associated cervical dysplasia and various cancers, we look forward to providing Inovio’s answer to MERS, a deadly infectious disease that has unknown pandemic potential.”

What’s even more impressive about the MERS vaccine candidate, Kim added, “is that it is designed with the goal to universally protect against multiple strains of MERS, which has been shown to have diverse genetic variants. With appropriate external funding, this product could become an effective shield against this deadly virus.”

In beginning the preclinical study, a consensus MERS “spike” protein vaccine construct was created based on multiple strains of the MERS virus. Inovio’s MERS DNA vaccine was immunogenic in mice and seroconversion was observed in all animals. Furthermore, the antibodies generated by the vaccine in 100 percent of the mice were able to neutralize or completely block actual infection of MERS virus in the cells. In contrast, none of the unvaccinated mice in the control group generated neutralizing antibodies.

Researchers also observed that vaccination was highly T-cell immunogenic, generating robust and broad T cell responses as extensively analyzed by the standardized T cell ELISPOT assay. The vaccine produced robust CD8+ and CD4+ T cell responses against multiple epitopes of the MERS spike protein.

This increased diversity and magnitude of cellular responses may be critical for effectively mitigating MERS infection, the company says.