Portola's 'breakthrough' anti-anticoagulant clears a Phase III hurdle

Portola Pharmaceuticals' ($PTLA) antidote to Big Pharma's latest crop of blockbuster blood thinners hit the mark in its first Phase III trial, clearing the way for an FDA submission next year.

The treatment, andexanet alfa, is designed to reverse the effects of drugs called Factor Xa inhibitors, which thin the blood by inhibiting the enzymes necessary for coagulation. Portola's drug works as a decoy, fooling such drugs into targeting it instead of the body's coagulation-regulating enzymes and thus reversing their effects and keeping patients safe in major bleeding events.

In its first Phase III trial, pitting it against Bristol-Myers Squibb ($BMY) and Pfizer's ($PFE) Eliquis, Portola's drug did just that. In a placebo-controlled study on 33 patients, injected andexanet alfa met its primary endpoint of restoring healthy Factor Xa levels with high statistical significance, the company said, proving it can quickly and effectively reverse the effects of Eliquis.

Now Portola is gearing up to file an FDA application by the end of 2015, counting on the agency's coveted breakthrough-therapy designation, which andexanet alfa received last year, to make for a speedy trip through review.

The biotech's shares are up 15% this morning.

The Eliquis trial is just one arm of Portola's sweeping late-stage effort for andexanet alfa. The company is working through a Phase III trial testing how well the drug can cancel out Bayer and Johnson & Johnson's ($JNJ) Xarelto and planning to test whether it can do the same to Daiichi Sankyo's in-development edoxaban starting next year.

Andexanet alfa's Phase III success sent Portola's shares up about 13% on Wednesday morning, and the biotech is still riding high off of the $122 million IPO it pulled off last year, trading at nearly double its initial price. 

Beyond the promise of its lead candidate, Portola is developing a Factor Xa inhibitor of its own, going it alone on a Phase III trial of betrixaban after ex-partner Merck ($MRK) handed back the rights in 2011. The biotech is also at work on the Phase I leukemia treatment cerdulatinib (PRT2070) and the early-stage asthma drug PRT2607, which is partnered with Biogen Idec ($BIIB).

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