Inovio Pharmaceuticals' Zika Vaccine Takes a Big Step Forward

Inovio Pharmaceuticals is steadily advancing its development of a potential Zika virus vaccine.

In February, the biotech announced positive results from testing of its Zika vaccine in mice. On May 16, Inovio took one step further in its quest to make it to market. The company reported that testing of its GLS-5700 vaccine for the Zika virus induced "robust" antibody and T cell responses in monkeys. This is probably the most important step for Inovio yet in its effort to develop the world's first Zika vaccine.

It's in the DNA

Make no mistake -- Inovio's earlier testing with mice was a big deal. The protein-coding portions of mouse and human genomes are around 85% identical. Especially because GLS-5700 is a DNA-based vaccine, the good results from testing with mice were meaningful.

But testing with non-human primates like monkeys is an even bigger deal. Humans and monkeys share around 93% of DNA. In Inovio's test, two doses of the Zika vaccine were administered to monkeys. All of the vaccinated monkeys showed specific antibodies in their blood. In addition, researchers found robust T cell responses in the animals.

What does all of this really mean? The results suggested that GLS-5700 could indeed prevent infection by the Zika virus. Antibodies are key in preventing infection. T cells can kill cells that harbor the Zika virus. The presence of both antibodies and broad T cell responses shows promise that Inovio's vaccine could ultimately prove to be effective.

Top banana

The important thing for investors to take away from Inovio's latest announcement is that the small biotech remains in the driver's seat in the race to develop a Zika virus vaccine. Inovio will now be able to move forward with testing in humans later this year. No other company appears to be that far along.

Sanofi announced in February that it plans to develop a Zika virus vaccine. The French drugmaker already has vaccines on the market forYellow Fever, Japanese Encephalitis, and Dengue. The company hopes that its Dengue vaccine could be leveraged quickly to also tackle Zika, because the two viruses belong to the same family. Unlike Inovio, though, Sanofi has not yet announced any pre-clinical testing results.

Another large pharmaceutical company could also be in the hunt. GlaxoSmithKline announced in January that it was evaluating whether its vaccine technology could be used to prevent infection by the Zika virus. Glaxo indicated that it planned to rapidly finish feasibility studies to determine if its vaccines might be effective for the Zika virus. However, the big drugmaker hasn't provided any updates since the January announcement.

The World Health Organization lists several other organizations working on Zika virus vaccines. Only two of them -- Inovio and Indian biotech Bharat -- had pre-clinical work in progress as of March. Bharat chairman Krishna Ella stated earlier this year that it would probably be 10 years before his company's Zika vaccine made it to market.

More bars to clear

Inovio's latest news is encouraging, but there's still a long way to go. The company will begin phase 1 human clinical testing this year. If all goes well, Inovio could then proceed to phase 2 testing. It's possible that the company could seek regulatory approval following phase 2 instead of after phase 3, as is usually the case. Either way, though, we're still at least several years away from seeing GLS-5700 hit the market.

The article Inovio Pharmaceuticals' Zika Vaccine Takes a Big Step Forward originally appeared on

Keith Speights has no position in any stocks mentioned. The Motley Fool has no position in any of the stocks mentioned. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.

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