The FDA has extended its timeline for reviewing Portola Pharmaceuticals’ AndexXa (andexanet alfa), a reversal agent for Xa inhibitor anticoagulants. The biologics license application (BLA) submitted by Portola revolves around data from the Phase III ANNEXA studies, which revealed AndexXa’s successful reversal of anticoagulant activity for two factor Xa inhibitor novel oral anticoagulants (NOACs): Johnson and Johnson/Bayer’s Xarelto (rivaroxaban) and Bristol-Myers Squibb/Pfizer’s Eliquis (apixaban).
Portola is attempting to expand AndexXa’s label to include approved reversal towards an additional NOAC, Daiichi Sankyo’s Lixiana/Savaysa (edoxaban), and a low molecular weight heparin, Sanofi’s Lovenox (enoxaparin). As such, the FDA has asked for additional data and time to review the BLA, as well as more manufacturing information. Originally, the FDA was set to make a decision by February 2018, but that date has now been pushed back to May 2018.
Despite this being a relatively minor setback to AndexXa’s approval and launch timeline, the lack of marketed factor Xa inhibitor NOAC reversal agents remains an unmet need in the cardiovascular space. If AndexXa is approved, factor Xa inhibitor NOAC developers will gain a significant marketing advantage through the potential increase in prescribing of factor Xa inhibitor NOAC products, as any remaining patient and physician fears surrounding bleeding occurring with their use will be alleviated.
After the launch of the NOACs almost a decade ago, starting with Boehringer Ingelheim’s thrombin inhibitor, Pradaxa (dabigatran), their uptake was initially slower than expected. This has been partially attributed to the lack of an NOAC reversal agent that could be employed in the case of a serious bleeding event. Since then, physician views on NOACs have evolved considerably, despite the fact that reversal agents only started to reach the market in 2015–2016 with Boehringer Ingelheim’s Praxbind (idarucizumab), a reversal agent for Pradaxa.
With encouraging data from multiple NOAC clinical trials and increased experience managing patients taking NOACs, physicians have acknowledged that NOACs offer several benefits, including the fact that they do not require regular monitoring and are known to be safer and non-inferior—if not superior—in efficacy to the historical anticoagulants, warfarin and heparin.
However, there are still no marketed reversal agents specific to factor Xa inhibitor NOACs, such as Xarelto, Eliquis, and Lixiana/Savaysa. Portola is awaiting the FDA’s decision for AndexXa, a first-in-class factor Xa inhibitor reversal agent. NOAC giants Bristol-Myers Squibb/Pfizer, Johnson and Johnson/Bayer, and Daiichi Sankyo have all entered a collaborative agreement with Portola to develop AndexXa. Portola also has a NOAC of its own, Bevyxxa (betrixaban), which is indicated for the prophylaxis of venous thromboembolism medically ill patients, and was approved in mid-2017.