Tarek Owaidah1, Abdulakareem Almomen2, Ahmed Tarawah3, Ashraf Warsi4, Fawaz Alkasim5, Hazzaa Alzahrani6, Mahassen Saleh7, Ohoud Kashari8, Wasil Jastaniah9,10. 1. Hematology and Transfusion Medicine, Department of Pathology and Laboratory Medicine (MBC 10), King Faisal Specialist Hospital and Research Center Alfaisal University Riyadh, Saudi Arabia. 2. Medicine-Hematology, King Saud University Medical City and Blood and Cancer Center Riyadh, Saudi Arabia. 3. Paediatric Haematology, Madina Maternity and Children Hospital Medina, Saudi Arabia. 4. Adult Haematology, College of Medicine, Umm Al-Qura University, Mecca, Saudi Arabia; Princess Norah Oncology Centre, King Abdelaziz Medical City, Ministry of National Guard Health Affairs-WR Jeddah, Saudi Arabia. 5. Paediatric Haematology, Maternity and Children Hospital Riyadh, Saudi Arabia. 6. Adult Haematology, King Faisal Specialist Hospital and Research Centre Riyadh, Saudi Arabia. 7. Paediatric Haematology, King Faisal Specialist Hospital and Research Centre Riyadh, Saudi Arabia. 8. Paediatric Haematology, East Jeddah General Hospital Jeddah, Saudi Arabia. 9. Pediatrics and Pediatric Hematology/Oncology/BMT, College of Medicine, Umm Al-Qura University Mecca, Saudi Arabia. 10. Princess Norah Oncology Center, King Abdulaziz Medical City, Ministry of National Guard Health Affairs WR Jeddah, Saudi Arabia.
Abstract
INTRODUCTION: Emicizumab is a bispecific monoclonal antibody with the ability to bridge FIXa and FX, mimic FVIII, and restore normal hemostasis in patients with hemophilia A. Moreover, substantial evidence has shown that emicizumab-treated patients do not require monitoring, except before surgery or invasive procedures. However, introducing this novel drug to the market poses some challenges to physicians and clinical laboratories due to its interaction with conventional coagulation tests. METHODS: Given the challenges and laboratory interactions posed by this novel drug, there is an unmet clinical need to develop clear recommendations for emicizumab laboratory monitoring to highlight which laboratory tests should be used, which tests should be avoided, and when these tests should be performed. These expert recommendations are essential to prevent inappropriate testing or misleading interpretations and reduce the extra costs of unnecessary monitoring. RESULTS: A consensus meeting was conducted in December 2019, including top experts on hemophilia from Saudi Arabia, to discuss this issue. CONCLUSION: The experts agreed that, aPTT (activated Partial Thromboplastin Time)-based tests are not suitable for laboratory monitoring patients treated with emicizumab. Only FVIII chromogenic assays based on bovine FIX and FX proteins can be used to measure FVIII levels. They reviewed and recommended the type and time of testing for anti-factor VIII antibodies. Drug levels should be measured using the recommended test only when the anti-drug antibody (ADA) is clinically suspected and after excluding other causes (such as patient non-compliance). AJBR
INTRODUCTION: Emicizumab is a bispecific monoclonal antibody with the ability to bridge FIXa and FX, mimic FVIII, and restore normal hemostasis in patients with hemophilia A. Moreover, substantial evidence has shown that emicizumab-treated patients do not require monitoring, except before surgery or invasive procedures. However, introducing this novel drug to the market poses some challenges to physicians and clinical laboratories due to its interaction with conventional coagulation tests. METHODS: Given the challenges and laboratory interactions posed by this novel drug, there is an unmet clinical need to develop clear recommendations for emicizumab laboratory monitoring to highlight which laboratory tests should be used, which tests should be avoided, and when these tests should be performed. These expert recommendations are essential to prevent inappropriate testing or misleading interpretations and reduce the extra costs of unnecessary monitoring. RESULTS: A consensus meeting was conducted in December 2019, including top experts on hemophilia from Saudi Arabia, to discuss this issue. CONCLUSION: The experts agreed that, aPTT (activated Partial Thromboplastin Time)-based tests are not suitable for laboratory monitoring patients treated with emicizumab. Only FVIII chromogenic assays based on bovine FIX and FX proteins can be used to measure FVIII levels. They reviewed and recommended the type and time of testing for anti-factor VIII antibodies. Drug levels should be measured using the recommended test only when the anti-drug antibody (ADA) is clinically suspected and after excluding other causes (such as patient non-compliance). AJBR
Authors: P Vincent Jenkins; Annette Bowyer; Clive Burgess; Elaine Gray; Steve Kitchen; Paul Murphy; Sean Platton; Anne Riddell; Pratima Chowdary; Will Lester Journal: Haemophilia Date: 2019-12-20 Impact factor: 4.287
Authors: Tarek Owaidah; Abdulkareem Al Momen; Hazzaa Alzahrani; Abdulrahman Almusa; Fawaz Alkasim; Ahmed Tarawah; Randa Al Nouno; Fatima Al Batniji; Fahad Alothman; Ali Alomari; Saud Abu-Herbish; Mahmoud Abu-Riash; Khawar Siddiqui; Mansor Ahmed; S Y Mohamed; Mahasen Saleh Journal: Medicine (Baltimore) Date: 2017-01 Impact factor: 1.889