Recently Inovio Pharmaceuticals (INO) announced positive results for an early stage HIV vaccine study. The vaccine in question, Pennvax - GP, is one that the company has developed. These preliminary results were the work of Inovio’s partners at the HIV Vaccine Trials Network — HVTN — and National Institute of Allergy and Infectious Diseases.

There were 76 patients evaluated for this reported data. Each of these patients were given a four-dose regimen program injected either intramuscular or intradermal. One thing to note is that the Pennvax-GP vaccine was combined with an immune activator by Inovio, known as INO-9012. The data showed that 71 out of 76 patients or 93% obtained a CD4+ or CD8+ cellular immune response to at least one of the four antigens given.

This was a remarkable result; the vaccine produced one of the best immune responses seen to date in a human HIV clinical trial. What one must keep in mind is that this study is early in nature. There are several factors that could change these results. 

First off, the study had a small group of patients. There would have to be a larger trial done to prove that the vaccine provides proper efficacy.

Secondly, the trial only indicated the immune responses observed by patients. A larger trial would have to incorporate the right data. For example, HIV clinical trials typically test what is known as viral load reduction. That means that the next few trials for Inovio will probably have to have a primary endpoint of viral reduction after one week of treatment with Pennvax-GP. This process will solidify positive data, data strong enough to submit to the FDA for approval.

Why did these early stage results move the needle? The answer lies in the fact that the HIV market is large. Currently, there is one major player that has a majority of the market. That player or rather company is known as Gilead Sciences (NASDAQ:GILD). The market is quite large as proven by how much Gilead produces from its HIV franchise. Each year Gilead pulls in $13 billion annually for its HIV drugs, which is a significant amount of revenue for one franchise. If Inovio is ultimately successful, its vaccine will prevent and treat HIV, potentially taking a lot of market share away from Gilead.