The US Food and Drug Administration has granted breakthrough therapy designation to Boehringer Ingelheim’s antidote to its blockbuster bloodthinner Pradaxa.

Idarucizumab is a fully humanised antibody fragment designed specifically to reverse the anticoagulant effects of Pradaxa (dabigatran etexilate). Data from a Phase I study have shown the drug is able to achieve “immediate, complete and sustained reversal of dabigatran-induced anticoagulation in healthy humans”, BI stated. The German group is now  conducting a Phase III trial is underway in patients taking Pradaxa who have uncontrolled bleeding or require emergency surgery or procedures.

Breakthrough designation differs from the FDA's other fast-track programmes as it involves more intensive guidance from the agency on putting together an efficient drug development programme. The criteria require preliminary clinical evidence that demonstrates the drug may have substantial improvement on at least one clinically significant endpoint over available therapy, and BI said it is planning to pursue an ‘accelerated approval pathway’ for idarucizumab.

The news comes a month after the company reluctantly agreed to settle 4,000 lawsuits in the USA filed over claims about the extent of bleeding risks associated with Pradaxa. BI has consistently backed the drug's positive benefit-risk profile, when used as directed, as has the FDA.

Sabine Luik, head of the firm’s medicine and regulatory affairs, said “we are confident in Pradaxa’s benefits and safety profile”, established in five pivotal trials including more than 27,000 patients. These studies were conducted without the use of an antidote and there are no specific antidotes for rival oral anticoagulants such as Bristol-Myers Squibb/Pfizer's anticoagulant Eliquis (apixaban) and Bayer/Johnson & Johnson's Xarelto (rivaroxaban), both Factor Xa inhibitors; the latter two firms are, however, are working with Portola Pharmaceuticals’ PRT4445 as an antidote to Factor Xa inhibitor blood thinners.