December 7, 2011 (Rockville, Maryland) — The US Food and Drug Administration (FDA) announced today that it is now investigating postmarketing reports of serious bleeding events in patients taking dabigatran etexilate (Pradaxa, Boehringer Ingelheim) [1].

"FDA is working to determine whether the reports of bleeding in patients taking Pradaxa are occurring more commonly than would be expected, based on observations in the large clinical trial that supported the approval of Pradaxa," according to the drug safety communication issued by the agency.

That large clinical trial is RE-LY. As reported previously by heartwire , rates of fatal bleeding were numerically lower with the higher dose tested in the trial--150 mg twice daily--at 0.23% per year (230 per 100 000 patient-years) compared with warfarin at 0.33% per year (330 per 100 000 patient-years). Life-threatening bleeds were more common, numerically, in the 150-mg group than in the 110-mg group tested in the trial. The 110-mg dose was not approved by the FDA, although it is on other worldwide markets.

Bleeding events with dabigatran have already prompted safety advisories in Japan and Australia and have led to labeling updates in Europe and the US focusing on the need for monitoring renal function. In November, Boehringer Ingelheim confirmed that between March 2008 and October 31, 2011 there were 260 fatal bleeding events worldwide.

The FDA said it will inform the public and clinicians about any new information about bleeding risks when it becomes available. In the meantime, the agency said it believes the anticoagulant provides an important health benefit when used as directed and that patients taking dabigatran should not stop taking the drug without talking to their doctor.

The FDA also noted that physicians should report adverse events or side effects related to dabigatran use to the FDA's MedWatch Safety Information and Adverse Event Reporting Program.