FDA backs Pradaxa safety as docs lament lack of antidote

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FDA has sifted the data on Pradaxa, the blood thinner that's attracted some controversy of late. And despite an onslaught of adverse-event reports--and hundreds of deaths--the agency says rates of gastrointestinal bleeding and intracranial hemorrhage were no higher in Pradaxa patients than in those using the older drug it was designed to replace.

FDA staffers reviewed insurance claims and other data from its early version of Sentinel, a safety-monitoring system the agency is developing. That assessment turned up bleeding at about the same rate for Pradaxa and warfarin as that found in late-stage research used to support the drug's approval. Conclusion? "Pradaxa provides an important health benefit when used as directed."

And therein lies the difficulty, or at least one of the difficulties, some cardiologists say. Pradaxa's label cautions its use in patients with substandard kidney function, but some doctors aren't testing their patients' kidneys before prescribing the drug.

The more dramatic difficulty is this: Pradaxa has no antidote. With warfarin, doctors can administer Vitamin K if patients start bleeding uncontrollably, to reverse the drug's effects. Pradaxa has no such failsafe. So, some patients have died from falls when doctors couldn't stop the bleeding.

Critics say that Pradaxa's use should be limited--or its risks better publicized--unless and until an antidote can be found, The New York Times reports.

Meanwhile, Boehringer Ingelheim is preparing to release new long-term safety data on Pradaxa, along with additional studies that examine, among other things, attempts to identify treatments for bleeding. And a "hypothesis-generating" study just published in the British Medical Journal actually found that stroke, major bleeding and intracranial bleeding were less common in patients taking Pradaxa for stroke prevention than with patients on a rival drug.

Pradaxa is a blockbuster. Its only head-to-head competitor in the warfarin-alternative market is Johnson & Johnson ($JNJ) and Bayer's Xarelto. That drug hasn't been tagged with so many safety reports, but to be fair, it hasn't been on the market nearly as long. Another potential competitor, Pfizer ($PFE) and Bristol-Myers Squibb's ($BMY) Eliquis, is still awaiting FDA approval. And meanwhile, FDA says it's planning to look at other data on Pradaxa's safety risks.

- get the FDA release
- read the NYT story
- see the BMJ study

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EMA supports Pradaxa but seeks sharper warnings for bleeding
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