The (Fab)ulous Destiny of Idarucizumab: Highlighting Its Interference with Urine Protein Immunofixation.

Héloïse Flament,Nadine Ajzenberg,Sofia Ortuno,Elena Litvinova,Nicolas Gendron,Dorothée Faille

doi:10.1055/s-0039-1697642

Abstract

Idarucizumab is a humanized antigen binding fragment (Fab) of a recombinant anti-dabigatran monoclonal antibody (IgG1-kappa) that allows rapid and sustained reversal of dabigatran-induced anticoagulation in case of bleeding or urgent surgery. Herein, we report a very unusual case of dabigatran reversal by idarucizumab in a 79-year-old woman with acute kidney failure admitted to a hospital in a context of hemoptysis. Three repeated injections were necessary because of massive dabigatran overdose and high rebounds of dabigatran plasma concentration. Idarucizumab was found on urine immunofixation up to 6 days after the last injection where it reacted with anti-kappa light chain antibody, but not with anti-gamma heavy chain antibody. Physicians should be aware of the increased half-life of idarucizumab in this context of acute kidney impairment and of its interference with urine immunofixation because it could lead to false-positive results and misdiagnosis of a paraprotein.

Highlights

Laboratoire d’Hématologie, Hôpital Bichat-Claude Bernard, AP-HP, Paris, France
Idarucizumab is a humanized monoclonal antigen binding fragment (Fab G1-kappa) that neutralizes anticoagulant effect of dabigatran[1,2] and can be used in emergency situations.[3]A 79-year-old woman was admitted to an emergency department for hemoptysis and progressive asthenia
We report a very unusual case of dabigatran reversal by idarucizumab in a 79-year-old woman with acute kidney failure admitted to a hospital in a context of hemoptysis

Summary

Introduction

Laboratoire d’Hématologie, Hôpital Bichat-Claude Bernard, AP-HP, Paris, France Université de Paris, INSERM, U1148, Paris, France 3 Laboratoire d'Immunologie-Hématologie, Hôpital Bichat-Claude Address for correspondence Dorothée Faille, PharmD, PhD, Department of Hematology, Bichat-Claude Bernard Hospital, 46 Rue Henri Huchard, 75877 Paris, France (e-mail: dorothee.faille@aphp.fr).

Results

Conclusion