Portola takes its 'breakthrough' bleeding drug to PhIII with Bayer, J&J in tow

Portola Pharmaceuticals' ($PTLA) promising antidote for blood thinners has attracted a who's who of Big Pharma partners, and now the biotech is advancing its reverser of Factor Xa inhibitors to Phase III with the help of Bayer and Johnson & Johnson ($JNJ).

Under the deal, the three will study how well Portola's andexanet alfa (PRT4445) can undo the anticoagulation effects of Bayer and J&J's Xarelto. Portola gets an undisclosed upfront payment along with potential milestones, the company said, and the biotech will hold onto worldwide commercial rights to its treatment.

Portola's drug essentially works as a Factor Xa decoy, fooling inhibitors like Xarelto into targeting it instead of the body's coagulation-regulating enzymes and thus halting the effect of blood thinners and keeping patients safe in major bleeding events. In Phase II results released last year, the treatment did just that, notching an immediate and dose-dependent reversal of Xarelto's effects. And andexanet alfa picked up an FDA breakthrough therapy designation in November, giving the Bay Area biotech hope for an accelerated approval.

"Through this expedited pathway, we have the potential to advance the investigation of this first-in-class Factor Xa inhibitor reversal agent from IND to BLA in under four years," CEO William Lis said in a statement.

And the treatment's potential as an antidote for a whole class of anticoagulants has drawn the interest of other drugmakers in the space, with Pfizer ($PFE) and Bristol-Myers Squibb ($BMY) partnering up with Portola to test andexanet alfa's effect on their Factor Xa-blocking Eliquis. In that deal, much like the one with Bayer and J&J, Portola is keeping commercial rights while advancing its compound to Phase III in part on its partners' dime, and the biotech expects to kick off both late-stage studies in the first half of this year.

Portola is still riding high off of the $122 million IPO it pulled off in May, and the company is now trading about 75% above its initial pricing. Beyond the promise of andexanet alfa, Portola is developing a Factor Xa inhibitor of its own, going solo on a Phase III trial of betrixaban after ex-partner Merck ($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).

- read the announcement

Special Report: The top 10 biotech IPOs of 2013 - Portola Pharmaceuticals

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