NovoSeven (recombinant factor VIIa) in centeral nervous systems bleeds

Critical appraisal of the role of recombinant activated factor VII in the treatment of hemophilia patients with inhibitors

Hemophilia patients with inhibitors faced the constraint of inadequate treatment for several years before the era of recombinant factor VIIa (rFVII). Initially, rFVIIa was used in the compassionate-use programs. After a worldwide license was issued, more than 1.5 million doses were administered. Bleeding of joints and muscles was controlled effectively by means of an early home treatment program, with either a standard dose of 90 μg/kg every 2 to 3 hours for a few doses or a single dose of 270 μg/kg. For more serious bleeding episodes or minor surgery, an initial dose of 90 μg/kg was given every 2 hours for 24 to 48 hours followed by increased intervals of 3 to 6 hours according to the severity of bleeding and efficacy of bleeding control. In cases of major surgery such as orthopedic procedures, the same regimen can be applied except for a higher initial dose of 120 to 180 μg/kg. However, increasing the dose should be considered if there are unexpected bleeding complications since the half-life and clearance of rFVIIa differ between individuals. In addition, prophylaxis is administered to a small number of patients. Finally, the reported thromboembolic events found in hemophilia patients with inhibitors receiving rFVIIa are extremely low, much less than 1%.

Recombinant activated clotting factor VII (rFVIIa) in the treatment of surgical and spontaneous bleeding episodes in hemophilic patients

Inhibitors against replacement clotting factors occur in approximately 30%–40% of patients with hemophilia A and 1.5%–3% of patients with hemophilia B. In this group of patients, bleeding events are best treated with bypassing agents. Recombinant activated factor VII (rFVIIa) has become the first-line agent in treating surgical and non-surgical bleeding in many centres with efficacy at standard 90 μg/kg doses approaching 90%. The greater efficacy is associated with early initiation of treatment, as well as, possibly larger doses of rFVIIa. A higher concentration appears to be essential in initiating an adequate thrombin burst, which results in a stable clot. Higher dosage regimens, home therapy and continuous infusion regimens are continuously evolving as we strive to define optimal dosing strategies in hemophilia patients. rFVIIa has been a remarkably safe agent for hemophiliacs but with high dosages being advocated and older patients being given such doses outside a trial setting, thromboembolic events remain a concern.

Intracranial haemorrhage in a boy with severe haemophilia A and factor VIII inhibitor

BACKGROUND

This report describes the case of a boy with severe haemophilia A and factor VIII inhibitor who suffered subarachnoid haemorrhage at age 7 years, followed by bleeding in the right cerebellar hemisphere and an epidural haematoma at age 12 years.

METHOD

The patient received intensive replacement treatment leading to reversal of neurological signs and symptoms and resorption of haematomas, as demonstrated by CT scans.

Recombinant Factor VIIa: A Review on Its Clinical Use

Recombinant activated factor VII (rFVIIa) (NovoSeven) is a novel hemostatic agent originally developed to treat bleeding episodes in hemophilic patients with inhibitors against coagulation factors VIII and IX. In recent years, rFVIIa has also been employed for the management of uncontrolled bleeding in a number of congenital and acquired hemostatic abnormalities. Based on a literature search including PubMed, references from reviews, and abstracts from the most important meetings on this topic, this review examines the current knowledge on therapy with rFVIIa, from the now well-standardized uses to the newer and less well-characterized clinical applications.

Congenital factor VII deficiency: therapy with recombinant activated factor VII - a critical appraisal

Congenital factor VII (FVII) deficiency is a rare bleeding disorder with high phenotypic variability, and optimal management has yet to be determined. Treatment has traditionally involved FVII replacement therapy using fresh frozen plasma, prothrombin complex concentrates or plasma-derived FVII concentrates. Recombinant activated FVII (rFVIIa, NovoSeven(R)), the first recombinant treatment option, has recently been approved in the European Union for use in congenital FVII deficiency, but has been available on an emergency and compassionate use basis since 1988. In FVII deficiency, rFVIIa serves as substitution therapy as it provides the physiological ligand (FVIIa) for tissue factor, its receptor exposed at the site of vascular injury. This paper provides an overview of published and unpublished experience with rFVIIa in patients with congenital FVII deficiency from the NovoSeven compassionate and emergency use programmes (1988-99) and of independent reports in the literature. Recombinant FVIIa has been reported to provide effective haemostasis in patients of all ages and in a range of bleeding situations, including acute central nervous system/life-threatening bleeding episodes (15 episodes in 12 patients), non-life-threatening bleeding episodes (>32 episodes in 17 patients), surgery (>40 interventions in 25 patients) and childbirth (three women). Preliminary reports suggest that it may also be effective prophylactically. The risk of thrombosis in FVII-deficient patients treated with rFVIIa is unknown, as is the occurrence of inhibiting antibodies. A postlicensure pharmacovigilance registry (Seven Treatment Evaluation Registry) has been set up to continue to monitor the efficacy and safety (including alloantibody development) of rFVIIa in patients with FVII deficiency.

A prospective pilot study of prophylactic treatment of preterm neonates with recombinant activated factor VII during the first 72 hours of life

OBJECTIVE

Intraventricular hemorrhage (IVH) in the preterm infant is a devastating complication, causing marked mortality and morbidity. A general hemostatic agent such as recombinant activated factor VII (rFVIIa) might have the potential to reduce the extent of severe IVH.

DESIGN

Prospective, single-arm pilot study.

SETTING

Level III neonatal intensive care unit.

PATIENTS

Ten preterm infants between 23 and 28 wks of gestation.

INTERVENTION

Administration of a 100-microg/kg rFVIIa bolus injection within the first 2 hrs of life, followed by 100 microg/kg rFVIIa every 4 hrs, for the first 72 hrs of life.

MEASUREMENTS AND MAIN RESULTS

Cranial ultrasonography and flow studies of the major arteries and the venae cava, aorta, vena portae, and venae renales, was performed at study enrollment and at 12 hrs, 24 hrs, 48 hrs, and 72 hrs. Blood cell counts and coagulation studies were performed. End points of the study were occurrences of adverse events, with an emphasis on thrombotic events or disseminated intravascular coagulation (DIC). Ten preterm infants with a gestational age of 23 wks 1 day to 28 wks 3 days were included. None had venous thrombosis or cerebral infarction during or after the treatment. Neither platelet consumption nor DIC was observed. Two infants with an umbilical artery catheter had a thrombus at the catheter tip (one during infusion of the study drug), which was successfully treated with heparin. One had grade III IVH and died on day 6 of life; in another, grade II IVH progressed to grade III after termination of the drug.

CONCLUSION

One hundred microg/kg rFVIIa does not accumulate if administered prophylactically to preterm infants of <28 wks of gestation every 4 hrs in the first 72 hrs of life. In this population, rFVIIa does not cause DIC. Thrombus formation was observed in two infants with umbilical artery catheters but in none of the infants with venous catheters. Embolic events were not observed. In this pilot study, which did not provide the sample size to assess any effect of rFVIIa on the incidence of IVH, 20% of the neonates went on to have grade III or IV IVH, which is similar to the rate in studies in which rFVIIa was not given.

Clinical use of recombinant FVIIa (rFVIIa)

Haemostasis is initiated by the complex formed by TF and FVIIa present in the blood (1% of the FVII protein). Recombinant FVIIa, which is active only after having formed complex with TF exposed following tissue damage, has been demonstrated to induce haemostasis in haemophilia patients with life- and limb-threatening bleedings with an efficacy rate of 76-84% in patients having failed on other treatment. Several had proven septicaemia but only one patient developed consumption coagulaopathy during extensive surgical manipulation and removal of myonecrotic tissue. No antibody formation against FVII has been seen in haemophilia patients. In 13 major surgical episodes complete intra- and post-operative haemostasis was achieved. rFVIIa has been used successfully in FVII-deficient patients and has been found to normalise the PT in patients with liver disease and in warfarin treated individuals. Single patients with platelet defects and with vWillebrand's disease type 3 achieved haemostasis with rFVIIa.