Pradaxa Health Risks Halt Mechanical Heart Valves Study

Problems associated with the use of Pradaxa among patients with mechanical heart valves were so severe that a clinical trial had to be aborted due to the danger posed for the participants.  

According to findings reported this week in the New England Journal of Medicine, patients with mechanical heart valves who were treated with Pradaxa suffered more instances of strokes, heart attacks and bleeding problems.

The clinical trial, known as RE-ALIGN, compared the effectiveness of Boehringer Ingelheim’s new blood thinner with warfarin, an older blood thinner that has been the standard anticoagulant used with mechanical heart valves. The drug maker had hoped to establish that Pradaxa may be safer and more effective than warfarin, but the results appeared to show just the opposite.

The trials looked at 252 patients. Out of 162 who were given Pradaxa, nine suffered strokes, and three suffered Myocardial Infarctions. There were none of either of those adverse events experienced among those given warfarin.

Researchers also found that four percent of the patients given Pradaxa suffered major bleeding events. Only two percent of the warfarin patients had bleeding problems. However, 27% of Pradaxa recipients had some kind of bleeding episode, compared with only 12% of those given warfarin.

The findings not only appear to disqualify Pradaxa use for patients with mechanical heart valves, but raise questions about earlier studies claiming to show that Pradaxa bleeding events and safety was about equivalent with warfarin. In addition, bleeding events caused by warfarin can be addressed with vitamin K, which acts as a reversal agent against the drug’s anticoagulant effects. There is no such reversal agent for Pradaxa, which can make bleeding events far more dangerous in some cases.

According to the researchers, during the course of the clinical trial about one-third of the patients given Pradaxa stopped using it altogether due to the risks or required their dose to be adjusted.

One of the researchers, Elaine M. Hylek, wrote an editorial to go along with the study’s findings. She called the results of the clinical trial disappointing.

“The Food and Drug Administration and the European Medicines Agency have recommended against the use of [Pradaxa] in patients with mechanical heart valves,” Hylek points out. “Off-label use will place patients at undue risk and is rightfully prohibited.”

Pradaxa Side Effects Raise Concerns

Pradaxa (dabigatran) was the first member of a  new class of anticoagulants, which was introduced in October 2010 as a stroke prevention alternative to warfarin, which is more commonly known as Coumadin.

Boehringer Ingelheim has aggressively promoted Pradaxa as superior to warfarin, because it requires less monitoring. However, a concerning number of reports involving uncontrollable bleeding problems with Pradaxa have surfaced since the medication hit the market.

This latest study comes less than two months after other studies raised concerns over the risks of Pradaxa heart attacks. While Pradaxa performed well against warfarin in the study, the authors wrote a letter to the journal pointing out that Pradaxa may increase the risk of heart attack by 48% when compared to controls.

A growing number of Pradaxa lawsuits are currently pending against Boehringer Ingelheim, which were brought by individuals who allege that the drug maker failed to adequately warn about the bleeding risk or the lack of a reversal agent for Pradaxa. Plaintiffs allege that they suffered severe and sometimes fatal injuries from hemorrhaging, which doctors were unable to control or stop.