Inovio Pharmaceuticals has announced that Inovio’s synthetic vaccine approach using a collection of synthetic DNA antigens generated broad protective antibody responses against all major deadly strains of H1 influenza viruses from the last 100 years including the virus that caused “Spanish Flu” in 1918 in multiple animal models including mice, guinea pigs and non-human primates.

The flu vaccine also affords 100% protection against lethal challenge in the gold standard ferret model, demonstrating the functionality of such broad protective immune responses. Preclinical flu vaccine study results were detailed in a paper published in the journal Vaccine entitled, “Broad cross-protective anti-hemagglutination responses elicited by influenza microconsensus DNA vaccine,” by Inovio scientists and its collaborators.

A broadly protective flu vaccine would be of great value given how rapidly a pandemic strain could emerge.  According to a recent editorial in Science Magazine: “….influenza viruses are moving targets, and a pandemic virus could nevertheless emerge with as little warning in 2018 as in 1918. As evidenced by this current flu season, influenza viruses can rapidly acquire mutations that evade our most recent vaccine formulations. A universal, broadly protective influenza vaccine for seasonal epidemics – a goal of intense research efforts -- would improve our preparedness for subsequent pandemics.”

Dr. Laurent Humeau, Inovio's Sr. VP, Research and Development, said, "Funded by a grant from the NIH, this published work demonstrates that Inovio’s ASPIRE™ (Antigen SPecific Immune REsponses) technology platform could produce a universal flu vaccine that can span seasonal vaccine changes allowing for continued immune protection. We are proud to advance Inovio technology and contribute to advance cutting edge technology for the important global health treats. These studies also showcase the latest CELLECTRA intradermal (skin) delivery system to facilitate optimal antigen production and generation of superior immune responses in animal models.”

Globally influenza remains an important pathogen contributing to significant deaths and illness each year. The CDC estimates that 56,000 Americans died from influenza-associated deaths in the United States during 2012-2013 flu season. Even with the seasonal flu vaccines generating $3.8 billion in global revenue (WHO estimate), the currently approved seasonal influenza vaccines provide protection against only the three or four strains included in their specific formulations and are therefore incapable of addressing the inevitable and frequent shift and drift of influenza viral strains that can occur from season to season. Scientists have long been searching for an influenza vaccine designed to be broadly protective against multiple, unmatched influenza virus strains.

In this published study, Inovio report on a synthetic micro-consensus approach that relies on a small collection of 4 synthetic H1HA DNA antigens which delivered in a single dose generated broadly protective antibody immune responses against several major deadly strains of H1N1 flu viruses from the last 100 years including the strain that caused the 1918 Spanish Flu (which killed over 40 million people) in mice, guinea pigs and non-human primates. The vaccine also protected 100% of immunized ferrets from a lethal virus challenge. These results are encouraging that a limited easy-to-formulate collection of micro-consensus antigens can be developed which can span seasonal vaccine changes allowing for continued immune protection.  All of these protective immune responses were generated using Inovio’s skin delivery system for vaccines. Perhaps most importantly, this novel strategy could also be used to develop broadly protective vaccines against other infectious agents like dengue, RSV and HIV.