Magazine article Drug Topics

Factor Xa Reversai Agent Receives Breakthrough Therapy Designation

Magazine article Drug Topics

Factor Xa Reversai Agent Receives Breakthrough Therapy Designation

Article excerpt


Portola Pharmaceuticals announced in late November 2013 that andexanet alfa, its investigational Factor Xa inhibitor antidote, has received breakthrough therapy designation from the FDA. The designation of breakthrough therapy expedites the development and review of drugs for serious or life-threatening conditions. Portola is pursuing accelerated approval for andexanet alfa and plans to initiate studies on a larger scale in 2014.

Recently presented study findings showed that andexanet alfa reversed the effects of apixaban by >90% within two minutes of an initial IV bolus and maintained that level throughout a two-hour infusion. These results came from a comparison of six volunteers given the agent and three controls who received placebo. They were part of a double-blind phase 2 study that randomized 54 volunteers to receive 5 mg apixaban twice daily followed by andexanet alfa at any of several dosages and infusion times. The reported results were for the highest tested bolus dose, 420 mg. No safety issues were identified.

The andexanet alfa molecule largely resembles factor Xa itself and competitively blocks the factor Xa-inhibiting effects of apixaban, rivaroxaban, enoxaparin, edoxaban, and the investigational betrixaban. If approved, andexanet alfa would be the first approved reversal agent for Factor Xa inhibitors.

Source: Stiles S. Portola antidote to Factor Xa inhibitors advances in dosing, safety studies. October 17,2013. http://www.medscape. com/viewarticle/812766. Accessed November 28,2013.

Medication persistence higher for dabigatran than for warfarin

A retrospective data analysis of 1,745 patients in a Department of Defense database suggests that patients with atrial fibrillation (AF) treated with dabigatran do a better job of taking their medication than do patients treated with warfarin.

The study showed that 63% of patients prescribed dabigatran were taking their medication after one year vs. 39% of patients who were prescribed warfarin. Medication persistence (defined as the duration of time from the initiation of treatment to discontinuation of therapy) was increased in older patients and those with highest stroke risk. It decreased with increasing risk of hemorrhage.

If patients failed to refill a prescription for either drug within an appropriate period (60 days), they were considered to have stopped treatment. …

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