Those zany Food and Drug Administration staffers are at it again. The advisory panel decision about Heplisav, the hepatitis B vaccine from Dynavax (DVAX -0.79%), will be announced tomorrow. FDA staff, though, released a report on Tuesday that stated Heplisav works with fewer doses than GlaxoSmithKline's (GSK -0.83%) Engerix-B vaccine and has a similar safety profile.

Is that a wee little hint of what the panel's decision might be? Mr. Market apparently thought so. Dynavax shares soared 13% that day, and intra-day trading carried share prices as much as 20% higher. I predicted in early October that investors could possibly more than double their money in 2013 by buying Dynavax. Is everything now full steam ahead?

Playing devil's advocate
Allow me to play devil's advocate first. An FDA staff report is a totally separate animal from an advisory panel decision. There's no way to know for sure what the panel might decide.

Furthermore, even if the advisory panel recommends Heplisav, that doesn't mean the FDA will necessarily approve the vaccine in February. It could find a flaw in the late-stage study and require Dynavax to perform more testing.

Mr. Market even might be having some doubts. Shares of Dynavax drifted lower in intraday trading today, the day leading up to the advisory panel decision.

Flame out
But even clergy would agree in saying to hell with the devil. Quite honestly, I doubt the panel will decide to recommend against Heplisav moving forward. And I strongly suspect that the FDA will approve the vaccine on Feb. 24 and that the European Medicines Agency will follow suit.

The staff report isn't the first potential harbinger of good news from the FDA. Earlier this year, it allowed Dynavax to expand the age range of adults to be included in the Biologics License Application for Heplisav. Dynavax initially planned to submit the BLA for healthy adults ages 40 and over, but the FDA gave the go-ahead to include healthy adults ages 18 through 70.

It even looks like the American Medical Association might be preparing for Heplisav's approval. In July, the AMA's Current Procedural Terminology panel included a new CPT code for adult two-dose hepatitis B vaccination schedules. Interestingly, the currently available vaccines -- Glaxo's Engerix-B and Twinrix and Merck's (MRK -0.11%) Recombivax -- have standard three-dose schedules for adults. Heplisav allows a two-dose adult schedule. 

Fired up
Investors in Dynavax have reason to be fired up about the stock. Shares are up nearly 70% over the past year. Most of that enthusiasm stems from the prospects for Heplisav.

The company has other products in the pipeline, too. It recently agreed with partner AstraZeneca (AZN -0.25%) to move forward with phase 1 trials for an asthma drug.

For now, the primary focus is justifiably on Heplisav.  I stand by my earlier prediction that the vaccine will gain FDA approval. I also still think that Dynavax shares will more than double between now and late 2013. It that doesn't happen, feel free to bring out your pitchforks.