Impact of Emicizumab on Activated Clotting Time Using the i-STAT Alinity Analyzer

Study Overview
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Brief Summary
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Emicizumab (Hemlibra®) is a subcutaneous hemostatic treatment approved in 2019 for the prophylaxis in severe hemophilia A. Emicizumab is a bispecific monoclonal antibody mimicking factor VIIIa that provides a constant level of coagulation similar to that observed in minor haemophilia A patients whose factor VIII level is 10-15%. Although the correction of plasma coagulation in vivo is only partial, emicizumab strongly shortens the in vitro coagulation times involving the intrinsic pathway such as aPTT(activated partial thromboplastin time). The investigators will evaluate the effect of emicizumab on a coagulation test (Activating clotting time (ACT i-STAT Alinity)) used as a point of care device to monitor heparin therapies during cardiac surgeries (cardiopulmonary bypass) and cardiac catheterizations. Because ACT is activated through the intrinsic pathway, it may also be shortened by emicizumab. Prophylactic treatment with emicizumab would make it impossible to use ACT for heparin therapy in a hemophiliac patient benefiting from this treatment. The aim of this in vitro study is to assess the effect of emicizumab on the in vitro heparin-induced ACT increase in severe hemophilia A patients treated with emicizumab and in healthy volunteers (measurement on the i- STAT Alinity) thanks to in vitro blood spiking experiments. Some data have already been published with other ACT devices (Hemochron..) but never with the i-STAT Alinity device which uses a different technology and other reagents.

Official Title
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Impact of Emicizumab on ACT (Activated Clotting Time) Using the i-STAT Alinity Analyzer: In Vitro Study in Severe Hemophiliacs A and Healthy Volunteers

Conditions
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Hemophilia A

Intervention / Treatment
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* Diagnostic Test: ACT


Participation Criteria
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Eligibility Criteria
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Inclusion criteria: severe hemophiliacs under emicizumab ( > 4 weeks) Exclusion Criteria: infusion of factor VIII < 5 days patients refusing to participate in the study protected persons anticoagulants

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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Male

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Severe hemophiliac patients under emicizumab<br> | Diagnostic Test: ACT<br>* ACT will be measured : after in vitro spiking with unfractionated heparin of blood samples from severe hemophilia A patients already treated with emicizumab after in vitro spiking with unfractionated heparin with or without emicizumab of blood samples from healthy volunteers<br>|
| Healthy volunteers<br> | Diagnostic Test: ACT<br>* ACT will be measured : after in vitro spiking with unfractionated heparin of blood samples from severe hemophilia A patients already treated with emicizumab after in vitro spiking with unfractionated heparin with or without emicizumab of blood samples from healthy volunteers<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Modification of ACT by emicizumab | Modification of the in vitro heparin-induced ACT increase by emicizumab | Day 0 | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Activated Clotting Time, Hemophilia, Emicizumab