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 the developmental-stage biopharma Portola Pharmaceuticals (NASDAQ:PTLA) ripped higher by more than 14% at one point today on the back of positive clinical trial news for its experimental compound Betrixaban. Betrixaban is a specific inhibitor of human factor Xa and is presently being assessed as a potential treatment for the prevention of venous thromboembolism (VTE), or blood clots, in patients hospitalized for heart and lung-related illnesses. 

Turning to the details, the company reported that an Independent Data Monitoring Committee recommended that the drug's ongoing late-stage trial dubbed "APEX" should continue as planned without modification.

What this means in layman's terms is that Betrixaban appears to be showing enough clinical benefit for this indication to allow the study to go on to completion. 

While there is no guarantee that the drug will ultimately meet its primary measures of efficacy in the final analysis, investors are apparently relieved that it at least hasn't flamed out at an early check point for futility. 

So what: According to the Surgeon General, VTE is one of the most preventable causes of in-hospital mortality in the United States. Despite significant reductions in VTE incidence rates using standard therapies, though, a large proportion of patients--especially those hospitalized for long periods of time--still suffer from blood clots after they are discharged, showing the need for new, more effective treatments.

Portola hopes that Betrixaban can become one of the first drugs approved for the prevention of blood clots in high-risk patients.

Now what: Betrixaban's ongoing late-stage study is reportedly more than 65% complete at the current time, with top-line results expected in early 2016. Although there will be about year's time before we know if it does indeed prevent blood clots in high risk patients, the drug's estimated target population of 20 million individuals living in G7 countries strongly suggests that it has blockbuster potential, making this mid-cap biopharma worth keeping tabs on going forward.