Long-Term Prophylaxis with Activated Recombinant FVII in Children with Hemophilia a and Inhibitor, Receiving Treatment with ITI Protocol

Background:

Recent studies have shown that addition of bypassing agents to immuno-tolerance induction (ITI) protocol for patients with hemophilia A and inhibitor results in better control of bleeding episodes and improves quality of life. Few publications have addressed prophylactic usage of recombinant factors VIIa in these settings. Due to relatively low infusion volume, convenience of administration and high efficacy rFVIIa - Coagil-VII seems to be especially reasonable for ITI protocol.

Aim: To assess the efficacy and safety of rFVIIa - Coagil-VII (SJC "GENERIUM", Russia) for prophylactic use during ITI protocol in patients with hemophilia A and inhibitor.

Methods:

Seven patients aged between 2 to 7 years with severe hemophilia A and inhibitor have been treated with ITI protocol using plasma derived factor VIII with von Willebrand factor. Seven of them simultaneously received treatment with Coagil-VII in individual doses (100-250 mkg/kg) and regimens (every 12 - 48 hours). When inhibitor reached level of 3 BU (Bethesda Unit) either dose or frequency of Coagil-VII administration were gradually reduced. After 1 BU the patients were given factor VIII only. Number and severity of bleeding events were assessed.

Results:

Five patients with high responding inhibitors and poor prognosis (history of high titer of factor VIII inhibitor, prolonged time between first inhibitor appearance and the beginning of ITI) received Coagil-VII in high doses 150 - 250 mkg/kg every 12-24 hours in 1-4 years. At time of booster effect titer of inhibitors reached 92 -16 000 BU. One of patients had ITI failure because of interruption of protocol, while 4 patients continue treatment. Level of 3 BU was reached by 4 patients at 40, 12, 35, and 3 months of treatment. Level of 1 BU was reached by 2 patients at 6 and 42 months of treatment. Significant clinical effect was achieved after 6 months of treatment. Time of bleeding episode was decreased from 7 (±2) to 2 (±1) days. Total number of hemorrhagic events, including hemarthrosis, hematomas and bleedings decreased by 3,7 fold (3,7 events per patient-month during first 6 months versus 1,0 events per patient-month). Only 1 hospital admission with bone fracture was recorded. All children have an active lifestyle and attend school.

Two patients with low responding inhibitor and good prognosis received Coagil-VII in low doses 90 - 170 mkg/kg every 24-48 hours. Maximal titer of inhibitor was 1.3 - 1.9 BU. Both patients completed treatment with Coagil-VII in 2 and 4 months and continue ITI protocol and both achieved undetectable level of inhibitor. No bleeding episodes were recorded in these patients since the beginning of treatment. There was no clinical or laboratory evidence of thrombosis, thrombocytopenia, or disseminated intravascular coagulation.

Conclusion:

We report our experience of prolonged (2 months - 4 years) prophylactic treatment with recombinant activated factor VII (rFVIIa) - Coagil-VII in patients with hemophilia A and inhibitor. This prophylaxis is efficacious when doses and treatment regimens are individually determined. This approach results in reduction of bleeding episodes in all patients, as well as increase of quality of life. No any adverse events (AE and SAE) with prolonged use of Coagil-VII have been registered so far.