What's happening

Shares of Portola Pharmaceuticals (NASDAQ:PTLA), a biotechnology company focused on the development of medicines to treat thrombosis and other hematologic disorders, tumbled as much as 10% during Tuesday's trading session. The reason for the tumble relates to a late Friday update to its biologics license application (BLA) for AndexXa, the company's reversal agent for patients taking an oral or injectable Factor Xa inhibitor who experience a serious uncontrolled or life-threatening bleeding event, or who require urgent surgery.

So what

The company update, provided on Dec. 22, notes that the Food and Drug Administration (FDA) is extending its BLA review process by 90 days to May 4, 2018 from Feb. 3, 2018, to allow for more time to review data associated with the Annexa-4 study, as well as discuss labeling and post-marketing commitments. In other words, shareholders are a bit annoyed (and worried) by the delay and what it could mean for AndexXa's chances for approval.

An hourglass on a table.

The waiting game continues for Portola shareholders. Image source: Getty Images.

For those who may not recall, Portola received a complete response letter (essentially a rejection) for AndexXa in August 2016, with the FDA requesting additional data to support the inclusion of edoxaban and enoxaparin in the label. Recently, Portola provided this additional clinical data to the FDA, so it's not entirely surprising that the FDA needs additional time to review it and finalize the drug's label and the company's post-marketing commitments. 

It's worth pointing out that this drug is also under review by the European Medicines Agency, with a final decision expected within the first half of 2018. Therefore, if it were to gain approval, it's possible that a European launch would occur before a U.S. launch. 

Now what

While this isn't the news that shareholders wanted to hear, it's certainly far from a backbreaker for Portola.

The company had Bevyxxa, a treatment for venous thromboembolism in hospitalized patients, approved this past June, and it has a possible path to $1 billion in annual sales by perhaps 2023, according to Wall Street.

The Annexa-4 study also demonstrated positive results that would seem to indicate approval is eventually in the cards. Of the 47 patients tested in the efficacy population, 37 were shown to have had excellent or good hemostasis 12 hours after the AndexXa infusion. 

In short, there remains a clear path to success for Portola, even with this minor hiccup. Keep your share-price appreciation expectations a bit modest considering that the company has yet to prove it can successfully grow its portfolio post-launch, but there's no reason to hit the exit based on the Dec. 22 press release.

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