Haemophilia therapies

[Mild hemophilia A fortuitously discovered during Henoch-Schönlein purpura]

Henoch-Schönlein purpura is a common form of immunological vasculitis in children. Hemophilia A is a genetic disorder, inherited in a X-linked recessive pattern, and characterized by spontaneous hemorrhage or prolonged bleeding due to factor VIII deficiency. The clinical signs depend on the severity of factor VIII deficiency. We herein report the case of a 4-year-old boy admitted to the emergency room for typical rheumatoid purpura, associated with a lengthening of aPTT, whose exploration had uncovered mild hemophilia A. Laboratory assays should explore lengthening of aPTT: firstly the presence of lupus anticoagulant without bleeding risk, in an inflammatory context; secondly a deficiency of VWF and one of the factors involved in the extrinsic coagulation pathway associated with bleeding risk.

Novel, high incidence exercise-induced muscle bleeding model in hemophilia B mice: rationale, development and prophylactic intervention

INTRODUCTION

Muscle hematomas are the second most common complication of hemophilia and insufficient treatment may result in serious and even life-threatening complications. Hemophilic dogs and rats do experience spontaneous muscle bleeding, but currently, no experimental animal model is available specifically investigating spontaneous muscle bleeds in a hemophilic setting.

AIM

The objective of this study was to develop a model of spontaneous muscle bleeds in hemophilia B mice. We hypothesized that treadmill exercise would induce muscle bleeds in hemophilia B mice but not in normal non-hemophilic mice and that treatment with recombinant factor IX (rFIX) before treadmill exercise could prevent the occurrence of pathology.

METHODS

A total of 203 mice (123 F9-KO and 80 C57BL/6NTac) were included in three separate studies: (i) the model implementation study investigating the bleeding pattern in hemophilia B mice after treadmill exercise; (ii) a study evaluating the pharmacokinetics of recombinant FIX (rFIX) in hemophilia B mice and based on these data; (iii) the treatment study, which tested therapeutic intervention with rFIX. At termination of the treadmill studies the presence of bleeds was evaluated.

RESULTS

Treadmill exercise resulted in a high incidence of muscle bleeds in F9-KO mice but not in C57BL/6NTac mice. Treating hemophilia B mice with rFIX before treadmill exercise prevented muscle bleeds.

CONCLUSION

A novel model of muscle bleeds in hemophilia B mice, responsive to rFIX, has been developed.

[Use of rFVIIa in intractable hemorrhage in patients on central veno-arterial ECMO]

OBJECTIVE

The purpose of our study is to describe the use of recombinant factor VIIa (rFVIIa) in patients on central veno-arterial ECMO with a particular attention on associated thrombotic complications.

STUDY DESIGN

Monocentric retrospective study.

PATIENTS AND METHODS

We examined 91 files of patients on ECMO between 2005 and 2010. During this period, eight patients presented refractory bleeding and benefited from rFVIIa treatment.

RESULTS

In six of the eight patients, the bleeding stopped. A decrease of the bleeding was noticed after the treatment of rFVIIa (before rFVIIa: 40.1±33.1mL/kg per 3 hours after rFVIIa: 5.4±3.2mL/kg per 3 hours (P=0.01). The transfusional needs were decreased after administration of rFVIIa. No thrombotic event was detected. Fibrinogen, d-dimers, platelet count and lactate were not modified by the treatment. Two patients were weaned from ECMO. One patient died 17 days after the weaning. The other patient survived without neurological damages.

CONCLUSION

The rFVIIa is a treatment of exception for patients on central veno-arterial ECMO and could be a last-resort treatment in the presence of a not curable massive bleeding.

Integrated analysis of safety and efficacy of a plasma- and albumin-free recombinant factor VIII (rAHF-PFM) from six clinical studies in patients with hemophilia A

BACKGROUND

Hemophilia A is an X-linked bleeding disorder that results from insufficient levels of factor VIII (FVIII) coagulant activity.

OBJECTIVE

To evaluate the efficacy and safety of ADVATE rAHF-PFM (Baxter Healthcare Corporation), a recombinant FVIII concentrate manufactured without human or bovine blood-derived additives, and to assess the effect of compliance with prophylactic use in preventing bleeding episodes (BEs).

METHODS

Clinical data were integrated from six prospective studies. Two hundred thirty-four hemophilia A subjects (FVIII levels < or = 2%) (median age 14.7 (range: 0.02 - 72.7) years) were included.

RESULTS

BEs were managed with one or two infusions and nearly all (1953/1956) responded to treatment. Compliance with a prophylactic treatment regimen significantly reduced the incidence of BEs (p = 0.0061) and prevented non-traumatic joint BEs (median annualized BE rate was 0). One previously treated subject developed an inhibitor; no other safety concerns were observed.

CONCLUSIONS

These results reinforce the efficacy and safety of rAHF-PFM and suggest that compliance is an essential contributor to the effectiveness of prophylaxis in the treatment of hemophilia A.

Evidence-based use of recombinant FVIIa (NovoSeven, NiaStase) for the treatment of hemophilia with inhibitors in children and adolescents

Children and adolescents comprise a significant proportion of the hemophilia population, including those patients who have developed inhibitors to factor VIII or FIX. We examine the use of rFVIIa for the treatment of bleeding episodes and the prevention of bleeding in children and adolescents with hemophilia A and B with inhibitors, focusing on registry data and recent clinical trial results. Based on this review of the literature, we conclude that recombinant FVIIa is safe and effective for use in controlling bleeding in these patient populations.

Factor VIII inhibitor bypassing activity (FEIBA) - addressing safety issues

Bypassing therapy is usually necessary to control or prevent bleeding episodes in patients with haemophilia A or B and high-titre inhibitors. Factor VIII inhibitor bypassing activity (FEIBA) has a long history of successful use in the acute, surgical and prophylactic treatment settings, but safety concerns have made some reluctant to administer this bypassing agent. A review of the literature and clinical trial data show that FEIBA has a low prevalence of thrombosis, a low prevalence of anamnesis that does not impact haemostatic efficacy and an excellent record of pathogen safety and clinical tolerability.