Background: Emicizumab is a recombinant, humanized, bispecific monoclonal antibody that substitutes for the function of FVIII by binding to activated factor IX and X. It is currently indicated for routine prophylaxis in adults and children of all ages with hemophilia A, with or without inhibitors. Despite basic guidelines provided by MASAC and the drug package insert, there is significant inter-institutional variability regarding monitoring and follow up in patients on emicizumab.
Objective: To outline our institutional experience in pediatric patients on emicizumab.
Method: Retrospective and prospective chart review of our patients on emicizumab. Information collected included age of patient, hemophilia severity, presence and titer of inhibitors, age when emicizumab was initiated and bleed management.
Results: We have 20 pediatric patients on emicizumab. Three with moderate and seventeen with severe hemophilia A. Age at the time of starting therapy ranged from 11mo-16years. The four youngest patients were started on primary prophylaxis with emicizumab by age 2. Five patients had inhibitors, two with high titer inhibitors. Prophylactic factor therapy was discontinued when emicizumab was initiated.
Labs included chromogenic FVIII activity and inhibitor within a month prior to starting therapy. Repeat levels are done at 3mo and then annually. Initial dose with teaching is done in clinic. Parents have the option to follow up weekly if needed. Scheduled visit are at week 5, 3mo, 6mo and 6 monthly thereafter. PTT is checked at each follow up. An educational checklist is completed by the provider and a nurse at the initial visit. Dose is recalculated at each visit based on weight. FEIBA is noted as a drug allergy in the patient’s chart. Central lines are removed after 3mo of emicizumab therapy. Single dose of factor product at 50 IU/kg or recombinant factor VII at 60-70mcg/kg has provided adequate hemostasis for minor surgical procedures. Most dental procedures have required only antifibrinolytic therapy. Majority of joint and soft tissue injuries are managed with RICE alone or a single dose of factor if there is a bleed. Most patients are on q2 or q4 week dosing for maintenance based on convenience and number of injections needed at a time.
Conclusion: The custom educational check list at our HTC has proven to be the most useful tool for our staff, patients and families. This has ensured adequate teaching and uniform monitoring for all the patients. A multi-institutional collaboration will help establish emicizumab monitoring guidelines for patients across the globe.
Abraham, Shirley; Lisa Jung; Janet Ratte; and Valerie Lowe. "An Institutional Experience With Emicizumab In Pediatric Patients With Heophilia A." (2020). https://digitalrepository.unm.edu/hsc_2020_pediatric_research/4