Boehringer Ingelheim has reported full data from the Phase III RE-SPECT ESUS clinical trial of its oral thrombin inhibitor Pradaxa (dabigatran etexilate) to prevent recurrent stroke in people with embolic stroke of undetermined source (ESUS).

The randomised, double-blind trial compared Pradaxa to acetylsalicylic acid (ASA) in a total of 5,390 patients across more than 40 countries.

The primary endpoint of the study was a clinically significant difference between the study drug and ASA on the risk of a recurrent stroke among post-stroke patients suffering with ESUS.

Data showed that the trial failed to meet the primary endpoint. A post-hoc analysis, however, revealed a treatment effect in favour of dabigatran after one year.

Safety analysis showed no significant difference in the risk of major bleeding between the dabigatran etexilate and ASA groups. Moreover, a comparable low risk for the most serious bleeding outcomes was observed.

Boehringer Ingelheim corporate vice-president and CardioMetabolic Medicine head Dr Waheed Jamal said: “The results from RE-SPECT ESUS provide highly interesting information, showing that dabigatran had a similar low risk of major bleeding compared to ASA in this high-risk population of post-stroke patients. This clearly reaffirms the positive risk-benefit profile of dabigatran.”

The company added that data from this trial expands the evidence supporting the safety profile of dabigatran etexilate. Study results were published in the New England Journal of Medicine (NEJM). 

ESUS is a type of cryptogenic stroke that accounts for one in six ischaemic strokes. After ESUS, most patients are treated with anti-platelet therapy, such as ASA, but one in three go on to experience a recurrent stroke within five years.

Pradaxa does not currently hold any regulatory approval for treating ESUS.