Idarucizumab for Emergency Reversal of the Anticoagulant Effects of Dabigatran: Final Results of a Japanese Postmarketing Surveillance Study.

Abstract

Idarucizumab, a monoclonal antibody fragment that rapidly reverses the anticoagulant effects of dabigatran, was approved in Japan in September 2016, at which time an all-case, postmarketing surveillance (PMS) study was initiated to collect data on idarucizumab in Japanese patients. Interim results were published previously, and the final results are reported herein. This multicenter, open-label, uncontrolled, non-interventional PMS study was conducted in Japanese patients who received idarucizumab at the approved dose (2 × 2.5g/50ml) and had uncontrolled bleeding (group A) or required an emergency procedure (group B). The primary endpoint was the frequency of adverse drug reactions (ADRs). The secondary endpoint was the maximum extent of reversal of the anticoagulant effects of dabigatran, within 4h of idarucizumab administration, based on activated partial thromboplastin time (aPTT). The final analysis included 804 patients. ADRs during the idarucizumab treatment and post-treatment periods were reported in 17 of 542 patients (3.1%) in group A and 12 of 240 patients (5.0%) in group B. Thrombotic events were reported in 22 patients (4.1%) in group A and 15 patients (6.3%) in group B, and hypersensitivity occurred in four (0.7%) and five patients (2.1%), respectively. Among 793 patients evaluated for effectiveness, 78 in group A and 26 in group B had aPTT data at baseline (immediately before idarucizumab administration) and within 4h of idarucizumab administration; in these patients, median maximum percentage reversal within 4h of idarucizumab administration was 100%. The final analysis from the PMS study confirms previous findings suggesting that idarucizumab can safely and effectively reverse the anticoagulant effects of dabigatran in Japanese patients in clinical practice. The results support the continued use of idarucizumab in Japan. This study is registered with ClinicalTrials.gov (NCT02946931).