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 Portola Pharmaceuticals (NASDAQ:PTLA), a clinical-stage biopharmaceutical focused on developing therapies to combat thrombosis and other hematologic disorders, dipped 10% today after the company announced a collaboration with Daiichi Sankyo (NASDAQOTH:DSNKY).

So what: According to a midday press release, Portola has entered into a second collaborative phase 3 agreement with Daiichi Sankyo to utilize andexanet alfa, its investigational Factor Xa inhibitor antidote, and Daiichi's Factor Xa inhibitor edoxaban. These studies, which will be known as ANNEXA, are scheduled to begin next year. This collaboration is considered nonexclusive, with Portola receiving an up-front payment, as well as additional development and regulatory milestone payments. Portola will maintain full worldwide rights to its Factor Xa inhibitor antidote.

Now what: Generally speaking, today's announcement is good news, but there some factors to consider. For one, a nonexclusive agreement allows Portola to collaborate with all Factor Xa inhibitors, but it also doesn't lock in a partner that clinical-stage biotech investors would love to see. In addition, since receiving the breakthrough therapy designation, Portola has been on fire; a cooling off period of shareholder profit-taking was expected. Lastly, a lack of definitive up-front payment and royalty figures might be upsetting existing shareholders who are left to ponder how lucrative its nonexclusive partnership with Daiichi Sankyo really is. Ultimately, I believe Portola is worth adding to your watchlist, but with a valuation north of $1 billion and no FDA-approved therapies as of yet, I'm certainly not a buyer here.

Sean Williams has no material interest in any companies mentioned in this article. You can follow him on CAPS under the screen name TMFUltraLong, track every pick he makes under the screen name TrackUltraLong, and check him out on Twitter, where he goes by the handle @TMFUltraLong.

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