Background:Patients with severe hemophilia A and inhibitors are at risk of bleeding during invasive procedures. The standard of care for preventing perioperative bleeding has been replacement therapy with FVIII concentrates or for patients with high-titer inhibitors, bypassing agents. However, there is no consensus on the appropriate management of surgery in patients receiving the novel agent emicizumab. The aim of this study was to demonstrate a case of a patient on emicizumab undergoing major surgery with bypassing agents with preoperative use of the thrombin generation assay (TGA) and thromboelastography (TEG).Methods:We report a patient with hemophilia A with inhibitors who had undergone a total knee replacement while on emicizumab combined with a bypassing agent. We utilized TEG and TGA to determine which bypassing agent to choose as well as to inform about the ideal dose.Results:We elected to use recombinant FVIIa as a bypassing agent for the surgery based upon the TGA results.Conclusion:The TGA can be utilized to support decision-making in patients on emicizumab undergoing major surgery to both predict efficacy and potentially minimize the risk of thrombotic events.
Hemophilia A is an inherited bleeding disorder characterized by deficiency of the coagulation protein factor VIII. Development of clotting factor concentrates has resulted in an excellent prognosis for this historically fatal disease. However, neutralizing antidrug antibodies to factor concentrates can develop, complicating management and worsening the prognosis, and thus creating an unmet need for novel therapies. One such agent is emicizumab, a bispecific monoclonal antibody which mimics the function of factor VIII. Collectively across the HAVEN clinical trial program, the rate of antidrug antibodies with neutralizing potential was 0.75%. Since its licensure, there have been no further reports of such antibodies, despite its use in thousands of patients. In this report, we describe a patient with severe hemophilia A with inhibitors who developed a neutralizing antidrug antibody to emicizumab, for whom we performed extensive testing in the special coagulation laboratory.
The standard of care in febrile neutropenic children is that they should be hospitalized, especially if high risk, and should be treated urgently with intravenous wide spectrum empiric antibiotics, the spectrum covering P. Aeruginosa. Empiric treatment should be modified according to culture results and clinical situation. Other options for low risk patients are starting with intravenous treatment and continuing with per oral treatment or giving per oral antibiotic treatment from the beginning.
Congenital plasminogen (Plg) deficiency leads to the development of ligneous membranes on mucosal surfaces. Here, we report our experience with local and intravenous fresh frozen plasma (FFP). We retrospectively reviewed medical files of 17 patients and their eight first-degree relatives. Conjunctivitis was the main complaint. Thirteen patients were treated both with intravenous and conjunctival FFP. Venous thrombosis did not develop in any. Genetic evaluation revealed heterogeneous mutations as well as polymorphisms. Diagnosis and treatment of Plg deficiency is challenging; topical and intravenous FFP may be an alternative treatment.
Introduction
Emicizumab is a humanized bispecific monoclonal antibody licensed for patients with severe haemophilia A with and without inhibitors. Management of breakthrough bleeding in patients with inhibitors on emicizumab involves episodic treatment with bypassing agents (BPA), activated prothrombin complex concentrate (aPCC) or recombinant activated factor VII (rFVIIa). Thrombotic events and thrombotic microangiopathy were reported when patients on emicizumab received concomitant aPCC at relatively high doses yet such events were not reported with rFVIIa. We studied the effect of spiking various concentrations of BPA on plasma taken from patients on emicizumab.
Material and Methods
Eleven patients with severe haemophilia A with inhibitors who are on emicizumab were recruited to participate. Blood samples drawn from patients were spiked in vitro with varying concentrations of aPCC and rFVIIa. All samples were tested utilizing global haemostasis assays, thromboelastography and thrombin generation assay.
Results
Thrombin generation increased with higher concentrations of spiked BPA with a normalized endogenous thrombin potential at a concentration of 0.05 IU/ml and 4 mcg/ml for aPCC and rFVIIa, respectively. Concentrations of aPCC in the range of licensed dosing led to excessive thrombin generation. Thromboelastography was not sufficiently sensitive.
Conclusion
Due to the known thrombotic complications when emicizumab is used in conjunction with aPCC, there has been a large‐scale abandonment of the use of aPCC in patients on emicizumab. However, it is possible that aPCC can be used safely with emicizumab albeit with lower doses than are typically prescribed. It would be important to test this hypothesis in a clinical study.
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