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Feature Anticoagulants

Dabigatran: how the drug company withheld important analyses

BMJ 2014; 349 doi: (Published 23 July 2014) Cite this as: BMJ 2014;349:g4670
  1. Deborah Cohen, investigations editor, The BMJ
  1. dcohen{at}

In an investigation by The BMJ Deborah Cohen finds that recommendations for use of new generation oral anticoagulants may be flawed because regulators did not see evidence showing that monitoring drug plasma levels could improve safety

An investigation by The BMJ shows how the manufacturers of a blockbuster anticoagulant stroke drug withheld from the regulators important analyses regarding how to use the drug as safely and effectively as possible.

Dabigatran is one of a new generation of oral anticoagulants for stroke prevention in patients with non-valvular atrial fibrillation recently recommended in guidelines from the National Institute for Health and Care Excellence for England and Wales.1 Guidelines in the US, Europe, and Canada have similarly recommended these drugs, in part because they don’t require monitoring of plasma levels or anticoagulant activity and subsequent dose adjustment, unlike older treatments such as warfarin.2 3 4

Yet information about dabigatran disclosed through previously confidential internal company documents released during litigation in the US—which they have settled for $650m (£380m; €480m)—and as a result of an investigation by The BMJ, show that the evidence on which these guidelines were based is incomplete.

In fact, Boehringer Ingelheim, the maker of dabigatran, has failed to share with regulators information about the potential benefits of monitoring anticoagulant activity and adjusting the dose to make sure the drug is working as safely and effectively as possible. The company also withheld analyses that calculated how many major bleeds dose adjustment could prevent. The company says that this information was not shared because the analysis did not provide a reliable prediction of patient outcomes.

Anticoagulation is a risky procedure. In the UK, warfarin is one of the drugs most commonly implicated in emergency hospital admissions as a result of major bleeds5 and the drug’s anticoagulant activity is …

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