FDA Launches New Study into Pradaxa's Safety

On Monday, the U.S. Food and Drug Administration’s Mini-Sentinel program posted a request for the public to submit comments on its protocol for a study on the safety of anticoagulant drug Pradaxa (dabigatran). The assessment will use data in the Mini-Sentinel Distributed Database (MSDD) to study the rates of bleeding in new dabigatran users who have been diagnosed with atrial fibrillation, or an abnormal heartbeat.

The study aims to determine the rates of bleeding and blood vessel blockage in new Pradaxa users compared to new warfarin users with atrial fibrillation.

Pradaxa has been the target of over 1,800 lawsuits filed by patients who suffered strokes and other serious side effects, with plaintiffs claiming that the maker of Pradaxa failed to release an antidote for the blood thinner. Pradaxa users who suffered injuries were subject to dangerous, sometimes life-threatening, bleeding that could have been avoided had the patient been prescribed a different blood thinner with an available antidote, such as warfarin, according to the lawsuits.

The analysis aims to determine the rates of bleeding and blood vessel blockage by blood clots (thromboembolism) in new Pradaxa users, as compared to new warfarin users, who have been diagnosed with atrial fibrillation. According to the protocol, dabigatran was the first oral anticoagulant approved by the agency for use in adults with atrial fibrillation for stroke prevention.

“Questions remain… about the outcomes associated with dabigatran outside of the clinical trial setting and in typical clinical practice populations,” the agency admitted in its protocol.

“A knowledgeable source said that the major purpose of the study will be to identify groups of patients who are at high risk for major bleeding events with dabigatran,” Forbes reported. The Mini-Sentinel noted that age and gender are the two subgroups of interest for the study’s outcome.

The agency will specifically monitor cases of ischemic stroke, intracranial hemorrhage, and episodes of major bleeding in patients over the age of 21 who are considered naïve to the anticoagulant. According to the FDA, this means that patients included in the analysis will have started using the drug less than 180 days prior to the beginning of the study. Warfarin was specifically chosen as a comparator due to the large number of current and potential users of the anticoagulant.

The Mini-Sentinel program uses pre-existing healthcare data from various sources to perform its analyses, collecting data from at least 17 healthcare partners and using more than 100 million patients’ medical records.

The public is encouraged to submit comments on the protocol by January 13, 2014.