Presentation Details
| Real-World Data on Emicizumab Prophylaxis in Older Persons with Hemophilia A: A Retrospective Single Center Cohort Study Shalini Vemuru1, Stacey Fedewa2, 3, Christine Kempton2, 3 . 1Department of Internal Medicine, Emory University School of Medicine, Atlanta, GA, USA.2Department of Hematology and Medical Oncology, Emory University School of Medicine, Atlanta, GA, USA.3Hemophilia of Georgia Center for Bleeding & Clotting Disorders of Emory, Emory University School of Medicine, Atlanta, GA, USA |
Abstract
BACKGROUND: Emicizumab is an effective treatment for hemophilia A. The thrombotic events observed in the phase 3 clinical trials have raised concern of using emicizumab in older populations, particularly those with underlying cardiovascular risk factors. However, real world data on the safety of emicizumab in older populations with hemophilia A, specifically whether these patients are at increased thrombotic risk, is limited. OBJECTIVES: This study aims to provide real-world evidence on the safety of emicizumab use in older patients with hemophilia A by investigating thrombotic events in patients ≥ 50 years old, who have begun emicizumab prophylaxis at a single Hemophilia Treatment Center (HTC). METHODS: This was a retrospective cohort study of patients ≥ 50 years old with severe and moderately severe hemophilia A, defined as baseline factor levels ≤2%, with or without inhibitors that began emicizumab since 2017 and were seen at Emory’s HTC. Demographic, comorbidity, and treatment data were collected from electronic medical records and analyzed with Fisher’s exact tests according to thrombotic events, defined as myocardial infarction, transient ischemic attack (TIA), cerebrovascular accident, deep venous thrombosis, or pulmonary embolism, occurring after emicizumab initiation. RESULTS: Twenty-six patients with hemophilia A, all male, were included in this study. One had a current inhibitor, three had a past inhibitor, and most (76.9 %) had previously received prophylactic factor replacement. The median observational time from initiation of emicizumab to the last date of follow up was 3.47 years [IQR 1.78 years]. Cardiovascular risk factors were common; 18 (69.2%) had hypertension, 11 (42.3 %) had hyperlipidemia, 3 (11.5%) had diabetes, and 14 (53.8%) had a smoking history. Two patients were on antiplatelet therapy during the study period. Prior to initiation of emicizumab, there was one thrombotic event, a TIA, which was followed by carotid endarterectomy. After initiation of emicizumab, three (11.5%) patients had a thrombotic event. One had experienced dysarthria secondary to a TIA. The second had a multifocal punctate bilateral middle cerebral artery infarct, although this was in the setting of simultaneous hemorrhagic stroke. The third had a left thalamic stroke. None of these three patients had prior thrombotic events or underwent surgery while receiving emicizumab. The time from initiation of emicizumab to thrombotic event was 836 days, 879 days, and 273 days, respectively. All these patients continued on emicizumab without a subsequent thrombotic event. Since emicizumab initiation, no significant differences in common cardiovascular risk factors (hypertension (p = 0.471), diabetes (p = 0.778), hyperlipidemia (p = 0.323), smoker (p = 0.111)) were found among patients with thrombotic events versus those without thrombotic events. CONCLUSIONS: In this cohort study of 26 patients seen at a single HTC, three thrombotic events occurred. Among those with a thrombotic event, all took emicizumab for over 200 days prior to their event and continued on emicizumab without a subsequent thrombotic event. In addition, most patients, even those with cardiovascular risk factors, did not have thrombotic events after initiation of emicizumab. This study adds to the small body of literature that supports emicizumab use in older adults with cardiovascular risk factors.
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No part of this publication may be reproduced, distributed, or transmitted in any form or by any means, including photocopying, recording, or other electronic or mechanical methods, without the prior written permission of the author.