As new anticoagulants seek to replace warfarin, hospitalists need to know all the facts before making therapy decisions
by Thomas R. Collins
As director of the hospitalist program at University of Utah Healthcare and the medical director of the University of Utah Health Care Thrombosis Service, Robert Pendleton, MD, closely monitored the progress of the anticoagulant dabigatran as it marched toward regulatory approval in the U.S. Developed by Boehringer Ingelheim and marketed as Pradaxa, the drug is a big deal.
“We were sort of primed and poised and anticipating that dabigatran would be approved,” Dr. Pendleton says. The FDA approved dabigatran in October for stroke prevention in nonvalvular atrial fibrillation patients. It is the first new oral anticoagulant approved in 50 years and the first of three drugs expected to mount a challenge to the longtime standard of care, warfarin (Coumadin).
When Dr. Pendleton’s hospital got ready to add the drug to its formulary, though, the process had to slow down. The hospital wasn’t quite ready for dabigatran.
“The first thing we did is sent out an institution-wide survey to get some understanding of baseline knowledge of practitioners who might be prescribing dabigatran … and found an enormous educational need,” Dr. Pendleton explains, but “most people who we anticipated would have been prescribing dabigatran, such as our cardiologists, had a very poor understanding of the clinical data and the drug itself.”
So University of Utah Healthcare developed an education plan for providers, made resources available so that providers could easily get information about the drug, and developed institutional guidelines on appropriate use, how they would handle off-label uses, and managing urgent situations. The drug was added to the formulary in February, and the change has been working out well, with “an exponential increase in prescribing,” Dr. Pendleton says.
The challenges at University of Utah Healthcare are being experienced—or probably soon will be—by hospitalists around the country as new oral anticoagulants become available for use. Experts say hospitalists need to take a keen interest in the new drugs, given the large number of CVT, VTE, atrial fibrillation, and other patients who are at an increased risk of clotting.
Most hospitalists see anticoagulated patients on a daily or weekly basis, experts say. Dr. Pendleton estimates that if you include patients who are on a preventive dose (e.g. to prevent DVT), as many as 80% or more of HM patients use anticoagulants.
“Anticoagulants are dangerous and they are often a bit tricky to use,” says Gregory Maynard, MD, MSc, SFHM, chief of the Division of Hospital Medicine at the University of California at San Diego, where he has won awards for their DVT prevention program. “If you look at the top three or four adverse drug events that occur, usually warfarin is one of those. … It’s common, it’s a safety issue, it’s tricky to use—all of those things add up to something that hospitalists need to pay attention to.”
Dabigatran, which inhibits thrombin, is part of a new anticoagulant parade, along with rivaroxaban (Xarelto) and apixaban, both of which inhibit Factor Xa. They offer patients attractive anticoagulant options that, unlike warfarin, don’t require blood draws for monitoring every few weeks. The new options also omit the lengthy list of drug and food contraindications of warfarin.
But questions about the ability to reverse bleeds while patients are on the new drugs, as well as concerns about their costs, are forcing hospitalists to evaluate carefully. So far, dabigatran is the only one approved in the U.S., and only for one indication.
The intention in development was to create “drugs that don’t require monitoring, drugs that have very little drug-drug interaction, and drugs that have no food interaction; a drug where you give a fixed dose and the patients get the same effect anticoagulation-wise,” says Geno Merli, MD, FHM, director of the Jefferson Center for Vascular Disease and CMO at Thomas Jefferson University Hospital in Philadelphia. “When you look at the studies, actually they do reasonably well. It’s a pretty big step.” (For a list of major anticoagulant studies, see Figure 1, below.)
Story continues below...
Rivaroxaban, being developed jointly by Bayer Healthcare and Johnson & Johnson, has been submitted to the FDA for approval for stroke prevention in nonvalvular atrial fibrillation patients, which would put it in direct competition with dabigatran. And apixaban, being co-developed by the global alliance of Bristol-Myers Squibb and Pfizer, expects to submit for the same indication approval this year, Bristol-Myers Squibb spokeswoman Christina Trank says. (updated June 16)
All three are under study for other indications, including VTE prevention after hip and knee replacement surgeries, and clot prevention in the acutely ill.
The stakes are high for the companies: Manufacturers and analysts estimate that the market for anticoagulants will top $10 billion by 2015, with some estimates even higher. Dabigatran has been in development by Boehringer for about 15 years and studied in more than 19,000 patients, spokeswoman Anna Moses says.
Bayer Healthcare says rivaroxaban’s development costs amount to more than $1.5 billion.
“I think all of them are promising,” says Shaun Mickus, a Johnson & Johnson spokesman. “We’re looking at meeting unmet medical needs. We have patients who, for one reason or another, are having blood clots in these indicated areas, and some of them are doing fine and getting the help they need, and others may not be.”
Boehringer spokeswoman Anna Moses said dabigatran is on formulary with 70% of the top 1,600 hospitals in the U.S.
“Our current focus is on efforts to educate physicians and payors about the product, including its efficacy, safety, and appropriate use,” Moses said in an email.
Data on Pradaxa for stroke prevention in nonvalvular atrial fibrillation might be encouraging, but to some experts, it’s not automatically going to prove to be a superior alternative to warfarin, says Ian Jenkins, MD, assistant professor in the Division of Hospital Medicine and part of the VTE prevention team at UC San Diego.
“It is, statistically, significantly better than warfarin for nonvalvular atrial fibrillation when you look at the stroke rate, but the number needed to treat is not small—it’s 172 patients a year,” Dr. Jenkins says. “So, as far as looking at an individual patient and saying, ‘Am I going to prevent a stroke in this person by switching them to dabigatran?’ it’s actually unlikely that you would. And depending on the type of institution you’re at and how good they are at managing warfarin, you might be able to get a similar improvement in their stroke risk by, say, improving the quality practices for warfarin use at your hospital.”
“I think a lot of people are reluctant to start it on people who are doing well on warfarin,” Dr. Maynard adds. “There’s a lot of people who have been fine for many years on warfarin, even though it’s a tricky drug.”
At Thomas Jefferson, Pradaxa’s use is restricted to cardiologists, hematologists, and the hospital’s vascular anticoagulation service, and a doctor outside those categories has to get a consult first, Dr. Merli says. At University of Utah Healthcare, off-label uses have to be funneled through the thrombosis service, Dr. Pendleton says.
Story continues below...
“Our concern was that our clinicians may use the drug for off-label indications and not for atrial fibrillation, as approved by the FDA,” says Dr. Merli, whose job as chief medical officer includes overseeing patient safety. “We felt that Pradaxa’s a good drug, has a good track record, but our fear was, how do we control the doctors who may want to use Pradaxa for other indications that have never been studied?”
Pradaxa also is considered for use in especially complicated cases that might be unsuitable for warfarin, he says.
A major consideration for the new drugs is that, unlike warfarin, they have no proven antidote should a patient have a bleeding episode while taking them. Warfarin patients are given vitamin K to ease the bleeding, but it’s not so simple with the new medications.
Dr. Merli expects those concerns will have a “big impact on physician utilization of these new agents.”
Experts say the main option in the event of a bleed on the new agents, at least for now, is to simply wait it out while giving the patient fresh frozen plasma.
“What if you fall down and hit your head and you bleed into your brain?” Dr. Merli asks. “I’m waiting for our first patient to come in, you know, with a massive brain bleed on Pradaxa.” The hospital, he notes, probably would treat with fresh frozen plasma, but then resort to Factor VII, which costs $10,000 to $12,000 per treatment.
Dr. Merli also says that the test recommended by Boehringer for assessing the degree of anticoagulation (the ecarin test) is not widely available. “That test is not available even at our hospital in Philadelphia,” he says. “The companies that make them tell us that in the case of Pradaxa, you can use the [activated] partial thromboplastin time as a measure of the degree of anticoagulation, but in the studies, there was no correlation.”
Then there is the cost hurdle. Warfarin, even with one or two blood tests a month to monitor international normalized ratio (INR) and assess its effectiveness, costs patients a total of $15 to $50 a month out of pocket. Paying cash for dabigatran is about $200 a month.
“Some sites haven’t added it to their formulary because they were concerned that it could get started in the hospital and then the patient might not be able to obtain it outside of the hospital, and then they would end up on no anticoagulation for a period of time,” Dr. Jenkins says.
On the flipside, dabigatran use could shorten hospital stays, saving costs. Patients on warfarin typically have to be weaned off faster-acting IV heparin first, then weaned onto warfarin. It also can take time to make sure anticoagulation is at the proper level, also extending the stay.
Boehringer Ingelheim spokeswoman Moses notes that the company is taking steps to address the cost. “Pradaxa is now included at the lowest branded copay level on formularies that insure about 35 percent of NVAF patients [Irregular heartbeat in a patient without a diseased, repaired, or replaced mitral heart valve] in the U.S.,” she wrote in an email. “For those patients who may not otherwise be able to afford treatment, BIPI [Boehring Ingelheim] offers patients assistance programs to help provide coverage for the cost of their medications.”
Dr. Merli expects the majority of physicians will take a wait-and-see approach to the new anticoagulants.
“I think 20 percent will adopt the drug early,” he says. “Then there’s that big group in the middle, 60 percent, that will wait and see and they’ll start using it. And then there’s that end group of 20 percent that will never use the drug.” TH
Thomas R. Collins is a freelance writer based in Florida.
The Hospitalist newsmagazine reports on issues and trends in hospital medicine. The Hospitalist reaches more than 25,000 hospitalists, physician assistants, nurse practitioners, residents, and medical administrators interested in the practice and business of hospital medicine.