Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

What: Shares of Dynavax Technologies Corporation (DVAX 1.81%), a clinical-stage biopharmaceutical company developing treatments for infectious and inflammatory diseases, jumped as much as 11% after announcing that data from two of its late-stage trials for heplisav, its investigational hepatitis-B vaccine, were published in the health journal Vaccine.

So what: According to one of the articles and commentaries from various physicians in Vaccine, heplisav "induced significantly higher seroprotection rates in all groups than the licensed comparator hepatitis-B vaccine in a shorter two-dose schedule over one month while maintaining a similar safety profile." In other words, it handily mopped the floor with the current standard of treatment for hepatitis B in safety, convenience, and efficacy.

Now what: But -- and here comes the "but," folks -- heplisav's efficacy has never really been the question, not even for the Food and Drug Administration. The big issue for Dynavax and heplisav is proving the safety of the vaccine. Following an FDA panel meeting in June, the FDA concluded that Dynavax would need to run an additional trial to prove the safety of its vaccine (the result of its meeting with the FDA would have severely limited the number of patients who could have used the vaccine were it to proceed without an additional safety trial). In addition, the FDA also raised manufacturing concerns in their meeting with Dynavax.

The truth of the matter is heplisav is no closer to an approval today with this new data out in Vaccine than it was a week ago. While an approval may still be in the cards, we're not looking at its safety trial being completed until well into next year -- and then it has to resubmit all over again! In sum, I'll gladly keep my distance from this stock for the time being.