What happened

Shares of Inovio Pharmaceuticals (NASDAQ:INO), a clinical-stage biotech company focused on the development of DNA-based immunotherapies and vaccines to treat cancer and infectious diseases, leaped higher by 20% during May, according to S&P Global Market Intelligence. Two major events appear to be responsible for Inovio's excellent month.

So what

Easily the biggest catalyst came on May 24, when Inovio announced preliminary results from its HIV study involving Pennvax-GP, which contains four HIV antigens designed to protect against multiple strains and elicit an immune response to treat and prevent HIV.

A biotech lab tech analyzing liquid in a beaker.

Image source: Getty Images.

According to the press release, 93% of the 76 evaluable vaccinated patients demonstrated an immune response to at least one of the vaccine antigens, while 94% of 66 evaluable patients demonstrated a specific antibody response.  Also noteworthy was that administration of Pennvax-GP vaccine and IL-12 with intradermal immunization led to a cellular response in 27 of 28 patients, and demonstrated an antibody response in 27 of 28 patients. Said Inovio's CEO Dr. J. Joseph Kim:

"These results are among the highest ever responses we've seen with an HIV vaccine, and they are remarkably consistent with our recent data reported from our Ebola, Zika and MERS clinical trials in terms of demonstrating nearly 100% vaccine response rates with very favorable safety profile. Furthermore, our newer and more tolerable intradermal vaccine delivery device showed that we can elicit very high immune responses at a much lower dose. We look forward to advancing PENNVAX-GP into later-stage clinical development with our partners and collaborators."

The other major event was Inovio's first-quarter earnings release on May 10. Revenue increased to $10.4 million from $8.1 million in the prior-year period, while net loss exploded higher to $23.1 million, or $0.31 per share, from $8 million, or $0.11 per share, in Q1 2016.  The higher costs were a result of more studies being conducted. But investors were pleased because Inovio's loss was narrower than expected, ending a streak of three straight quarters with wider-than-expected losses.

Dice that read "buy" and "sell" being rolled on a financial newspaper.

Image source: Getty Images.

Now what

The big question, of course, is where will Inovio Pharmaceuticals go from here?

On one hand, the HIV study results are exciting, and do demonstrate the promise of Inovio's proprietary immunotherapy vaccine development platform. Adn given that it has nearly $90 million in cash on hand, Inovio's cash burn also isn't a major concern.

However, that HIV program is also years away from any chance of commercialization. For now, the hopes of Inovio and its shareholders rest with VGX-3100, which is being examined as a treatment for cervical dysplasia. Even though VGX-3100 won't likely have major sales implications for Inovio, it would,  if approved, validate the company's drug-development platform. Even so, we're years away from analyzing late-stage data on VGX-3100.

For now, this Fool would suggest safely monitoring Inovio from the sidelines, and waiting for clear late-stage evidence that its platform can yield positive results in a larger patient pool.

Sean Williams has no position in any stocks mentioned. The Motley Fool has no position in any of the stocks mentioned. The Motley Fool has a disclosure policy.