The new anticoagulants on the U.S. market – dabigatran (Pradaxa), apixaban (Eliquis), and rivaroxaban (Xarelto) – are gaining ground and widely acknowledged to be better, safer, and easier to manage. But warfarin clings to the market largely because of familiarity and low price, according to several experts.
Mitchel L. Zoler/Frontline Medical Communications
Dr. Munir Pirmohamed
"There is no doubt that the new anticoagulants look better compared with warfarin, but the clinical fact is that it’s what you know versus what you don’t know, and warfarin has been used for 60 years," Dr. Kimmel said at the press conference.
"The new drugs perform better than warfarin does; they get patients to where they need to be more quickly, but warfarin has been around a long time. We know its interactions and risks, there is the ability to reverse its effect, and the cost to patients is a real issue. If the new anticoagulants were the same price as warfarin then I think you’d see a lot more patients get a new drug," Dr. Ellinor said in an interview.
Data on current U.S. uptake of the new oral anticoagulants came from the 148,320 unique patients with atrial fibrillation included during June to September of 2013 in the PINNACLE Registry database run by the American College of Cardiology. Among these patients, about 83,000 (56%) were on some anticoagulant treatment, and within this subgroup, 72% were on warfarin, 27% on a new anticoagulant, and the remainder on different treatment, said Dr. John Gordon Harold, ACC president and a cardiologist at Cedars-Sinai Heart Institute in Los Angeles.
"In my own practice the new anticoagulants are being used with increasing frequency, mainly driven by direct-to-consumer advertising," Dr. Harold said in an interview. "We have patients who are completely stable on warfarin. (They) come in because of a consumer ad and they ask if they should switch drugs. When patients are stable I don’t encourage them to switch, but we have a shared decision making conversation and go over the pros and cons, the cost, and the outcomes data. A lot of patients prefer to pay the difference" and switch to a new anticoagulant.
Dr. Harold said he also recommends that patients switch off warfarin if they have problems with compliance and variability in their international normalized ratio (INR).
"If you can keep a patient on warfarin in their INR target range 80% or more of the time then I wouldn’t change, but most patients on warfarin have a very hard time maintaining an INR of 2-3," said Dr. Mark S. Link, professor and codirector of the cardiac arrhythmia center at Tufts Medical Center, Boston. But he said cost is a major factor keeping many patients on warfarin.
The new anticoagulants "are better than warfarin, but we are often forced by insurers to start with the cheaper drug," Dr. Link said during the news conference.
The COAG and EU-PACT studies did not receive any direct commercial sponsorship. Dr. Kimmel has been a consultant to Pfizer and Janssen. Dr. Hylek has been a consultant or adviser to Bayer, Boehringer Ingelheim, Bristol-Myers Squibb, Daiichi Sankyo, Johnson & Johnson, and Pfizer. Dr. Pirmohamed, Dr. Ellinor, Dr. Harold, and Dr. Link had no relevant disclosures.
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