E Portola Pharmaceuticals Inc. Is A Stock To Watch With Caution Ahead Of PDUFA

Now, sometimes, these anticoagulants have too much of an impact. They thin blood excessively, and lead to blood loss. This is where Andexanet alfa comes into the picture. It's an antidote for factor Xa inhibitors, designed to render them useless (or at least, incapacitated in terms of efficacy). It does this by mimicking factor Xa, but (by ways we don't really need to go into too much detail here) having a higher affinity to the inhibitors than the natural Xa does. In other words, it looks more like Xa to the inhibitors than Xa does. This means the inhibitors bind to Andexanet alfa, rather than the natural Xa, leaving the natural Xa to go about its coagulating duty. Simple.

Portola has developed both sides of the equation as its two lead candidates. The drug for which data hit markets, and on which the company's market capitalization tanked in March, is a factor Xa inhibitor called Betrixaban. To quickly touch on this, the data did hint at efficacy, but a slightly odd trial design mean that statistically the drug didn’t meet its phase III endpoint. In this author's opinion, the swift decline was a bit harsh, but that's for another discussion.

The candidate we are looking at is the antidote to its Betrixaban, and other factor Xa inhibitors. The trial on which the BLA for the drug is based is a phase III that pitted Andexanet alfa against two already well established factor Xa inhibitors, rivaroxaban and apixaban, in healthy volunteers. The data indicated a certain level of efficacy, and no serious adverse events arose as part of the trial. This bodes well for the drug's chances come PDUFA, as with little to no safety issues, the FDA is often (and increasingly) willing to give a green light on the assumption that it's better to have another safe alternative available to the current SOCs in the space than not.

So what's the market potential, and what would an approval mean for Portola? In the US, every twelve months, around 50,000 patients that have taken a factor Xa inhibitor are admitted to hospital for bleeding issues. Globally, Portola believes there are around 100,000 patients who would right now benefit from its antidote. Based on anticoagulant growth, expectations put this number at 500,000 in G7 countries by 2020. With no current antidotes approved that target factor Xa inhibitors, an approval for Andexanet alfa come PDUFA would be a big deal.

View single page >> |

Disclosure: None

How did you like this article? Let us know so we can better customize your reading experience. Users' ratings are only visible to themselves.


Leave a comment to automatically be entered into our contest to win a free Echo Show.