title: Importance of pharmacokinetic studies in the management of acquired factor X deficiency.
abstract: Up to 14% of individuals with systemic AL amyloidosis develop acquired factor X deficiency, which occurs due to adsorption of factor X onto amyloid fibrils. Although baseline factor X levels are not predictive of bleeding risk in these patients, serious hemorrhagic complications can occur, particularly during invasive procedures. Optimal management strategies to attenuate bleeding risk in these patients are unknown. We describe our experience in the management of acquired factor X deficiency, secondary to systemic AL amyloidosis, in a case series of three patients who received prothrombin complex concentrates (PCCs) for treatment and prevention of bleeding events. We performed a retrospective review extracting information on baseline demographics, laboratory data, pharmacokinetic (PK) studies, and clinically documented bleeding events. Our case series demonstrates that individuals with acquired factor X deficiency secondary to amyloidosis have variable laboratory and clinical responses to PCCs. This is likely due to distinct amyloid loads and fibril sequences, leading to different binding avidities for factor X. Our data emphasize the importance of performing PK testing prior to any invasive procedures to determine the dose and frequency interval to achieve adequate factor X levels for hemostasis, given the variable response between individuals.
authors.affiliation: Department of Medicine, Division of Hematology/Oncology, University of North Carolina, Chapel Hill, NC, USA.
authors.forename: Ming Y
authors.initials: MY
authors.lastname: Lim
authors.affiliation: Department of Medicine, Division of Hematology/Oncology, University of North Carolina, Chapel Hill, NC, USA.
authors.forename: Timothy
authors.initials: T
authors.lastname: McCarthy
authors.affiliation: School of Pharmacy, University of North Carolina, Chapel Hill, NC, USA.
authors.forename: Sheh-Li
authors.initials: SL
authors.lastname: Chen
authors.affiliation: Department of Pathology and Laboratory Medicine, University of North Carolina, Chapel Hill, NC, USA.
authors.forename: Marian A
authors.initials: MA
authors.lastname: Rollins-Raval
authors.affiliation: Department of Medicine, Division of Hematology/Oncology, University of North Carolina, Chapel Hill, NC, USA.
authors.forename: Alice D
authors.initials: AD
authors.lastname: Ma
mesh_terms: D000328:Adult; D000368:Aged; D000686:Amyloidosis / Q000097:blood / Q000150:complications / Q000188:drug therapy; D001779:Blood Coagulation Factors / Q000008:administration & dosage / Q000493:pharmacokinetics; D005171:Factor X Deficiency / Q000097:blood / Q000188:drug therapy / Q000209:etiology; D005260:Female; D006801:Humans; D008297:Male; D012189:Retrospective Studies
chemical_list: D001779:Blood Coagulation Factors; C025667:prothrombin complex concentrates
keywords: acquired factor X deficiency; pharmacokinetic; treatment