As mentioned in a previous post, the fourth novel oral anticoagulant (NOAC) has entered the market with the launch of Savaysa (edoxaban). Savaysa joins Pradaxa (dabigatran), Xarelto (rivaroxaban), and Eliquis (apixaban); all agents have indications for atrial fibrillation (AF) and deep vein thrombosis (DVT). However, this new class of drug has not made the expected inroads versus the long standing competitor warfarin or Coumadin. This has been a surprise to many, since it was assumed that warfarin with all its challenges would be defeated by these new, more convenient agents.
Warfarin still maintains ~80% of the market with the other agents fighting for the 20%. While these newer agents come with an increased price tag, the belief has been that safety benefits and the lack of required INR monitoring would easily displace warfarin. What is the challenge for these agents? These can be listed as follows:
- Some patients do well on warfarin, especially in areas with anticoagulation clinics
- Anticoagulation clinics drive income for the institutions that have them; these institutions do not want to see the clinics disappear
- Physicians have 50 years of experience in using warfarin
- Warfarin costs the patient pennies a day; a benefit to these older patients who are on a fixed income
- INR testing can be a social experience for older patients
- There is no reversal agent on the market for the NOACs, which means if a patient experiences a bleed, there is no FDA approved method to address this
Physicians and payers alike have stated that the last point, a reversal agent, is probably the most significant reason that the NOACs have not gained more than a small share of the market. While warfarin may be less safe and cause bleeds, there is a proven and approved reversal agent in vitamin K.
Portola Pharmaceuticals is currently developing andexanet alfa (PRT4445) for the reversal of FxA inhibition. This agent has received a breakthrough therapy designation by the FDA and, in addition, received orphan drug status on February 26. If this agent is approved and comes to the market, it may be the game changer that is needed to help the NOACs gain market share.
Stay tuned for more on how the market landscape takes shape in the coming months!