Pradaxa Study Finds New Blood Thinner Hasn’t Had Much Effect on Treatment of Atrial Fibrillation

A new Pradaxa study conducted by U.S. researchers has found that Pradaxa hasn’t really changed the way doctors treat atrial fibrillation, its approved indication.  According to a report from the UPI, the same study also found that a growing number of doctors are using the Pradaxa for blood clots and other off-label indications.

The study, which was conducted by researchers at the Johns Hopkins Bloomberg School of Public Health, found that while doctors rapidly adopted Pradaxa to reduce the risk of stroke in patients with atrial fibrillation, the majority of patients with the condition (2 in 5) still aren’t receiving any anti-coagulant therapy at all.  According to the UPI, the study drew data from the IMS National Disease and Therapeutic Index, and quantified pharmacy expenditures for Pradaxa and warfarin from 2007 to 2011.

While most doctors who did prescribe Pradaxa did so for the treatment of atrial fibrillation, a growing number are using the drug for off-label uses, the authors said. Other key findings of the study, which is published in the journal Circulation: Cardiovascular Quality and Outcomes, include:

• Between 2007 and 2011, warfarin treatment visits declined from ≈2.1 million (M) quarterly visits to ≈1.6M visits.
• Pradaxa use increased from 0.062M quarterly visits (2010Q4) to 0.363M visits (2011Q4), reflecting its increasing share of oral anticoagulant visits from 3.1% to 18.9%.
• While the majority of Pradaxa visits have been for atrial fibrillation, though this proportion decreased from 92% (2010Q4) to 63% (2011Q4), corresponding increases in Pradaxa’s off-label use.
• Among atrial fibrillation visits, warfarin use decreased from 55.8% visits (2010Q4) to 44.4% (2011Q4), while Pradaxa use increased from 4.0% to 16.9%.
• Expenditures related to Pradaxa increased rapidly from $16M in 2010Q4 to $166M in 2011Q4, exceeding expenditures on warfarin ($144M) in 2011Q4.

Pradaxa was approved by the U.S. Food & Drug Administration (FDA) in October 2010 to prevent strokes in patients with an irregular heartbeat called non-valvular atrial fibrillation as a warfarin replacement. The FDA launched a review of Pradaxa this past December over reports of bleeding-related side effects, while regulators in Europe and Japan have directed Boehringer Ingelheim to strengthen warnings for the drug.  According to the Institute for Safe Medicine Practices’ (ISMP) latest QuarterWatch report, the FDA received 3,781 adverse event reports associated with Pradaxa in 2011.  These included 541 deaths, 2,367 reports of hemorrhage, 291 reports of kidney failure and 644 reports of stroke.  Pradaxa was also a suspect in more than 15 cases of liver failure reported to the FDA.

Both Pradaxa and warfarin can cause internal bleeding, but there are readily available antidotes for warfarin bleeding.  A growing number of Pradaxa bleeding lawsuits allege the drug caused serious, uncontrollable bleeding side effects, including gastrointestinal bleeding and cerebral hemorrhaging for which there is no reversal agent.