Assaying the Circulating Factor VIII Activity in Hemophilia A Patients Treated with Recombinant Factor VIII Products

2002 ◽  
Vol 28 (3) ◽  
pp. 257-264 ◽  
Author(s):  
Marianne Mikaelsson ◽  
Ulla Oswaldsson
Keyword(s):  
Factor Viii ◽  
Hemophilia A ◽  
Recombinant Factor Viii ◽  
Factor Viii Activity

Quantitative Evaluation of Factor VIII in Factor VIII Products.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 4012-4012
Author(s):  
Saulius Butenas ◽  
Behnaz Parhami-Seren ◽  
Matthew T. Gissel ◽  
Edward D. Gomperts ◽  
Kenneth G. Mann
Keyword(s):  
Factor Viii ◽  
Protein Content ◽  
Quantitative Evaluation ◽  
Hemophilia A ◽  
Specific Activity ◽  
Full Length ◽  
Recombinant Factor Viii ◽  
Factor Viii Activity

Abstract Several factor VIII products, recombinant and natural, have been used for hemophilia A treatment worldwide. Typically, two activity-based assays (factor Xase and aPTT) are used for the assessment of factor VIII concentration in these products. Frequently, the results are dependent upon the assay and its modifications in different laboratories. In this study, we evaluated five pharmacologic factor VIII products (three lots of each) in three activity-based assays and in two immunoassays for the concentration and activity of factor VIII protein. Two factor VIII products were plasma-derived (Immunate and Hemofil M) and three were recombinant; two of these contained full-length factor VIII (Recombinate and Kogenate) and one was B-domainless (ReFacto). Albumin-free full-length recombinant factor VIII was used as a standard in all assays. In the factor Xase assay, all recombinant factor VIII products and Immunate at 1U/ml (indicated by manufacturer) showed activity similar to that of 0.7nM (1U/ml) standard, whereas activity of Hemofil M was 64–68% of the standard. In the aPTT assay both full-length recombinant products and Hemofil M displayed activity similar to the standard, whereas Immunate had increased (142% of standard) and ReFacto decreased (83% of standard) activity. In synthetic plasma, all three recombinant products had standard-like activity, whereas Hemofil M and Immunate were slightly more active than standard. The ELISA immunoassay revealed that the factor VIII protein content in Recombinate, Kogenate and Hemofil M corresponded to the units assigned by manufacturers (1.4–1.6x1012U/mol vs1.4x1012U/mol calculated for standard), whereas the specific activity of Immunate was 50% of that expected (0.7x1012U/mol). In contrast, the specific activity of ReFacto was almost 3-fold that of full-length factor VIII (4.0x1012U/mol). The data of this study indicate that: 1) factor VIII activity estimated in different assays gives dissimilar results; 2) the specific activity of factor VIII in various factor VIII products is different and, as a consequence, administration of an equal factor VIII activity in U/ml means the administration of different amounts of factor VIII protein.

Measurement of factor VIII activity of B-domain deleted recombinant factor VIII

2001 ◽  
Vol 38 (2, Suppl 4) ◽  
pp. 13-23 ◽  
Author(s):  
M. Mikaelsson ◽  
U. Oswaldsson ◽  
M. A. Jankowski
Keyword(s):  
Factor Viii ◽  
Recombinant Factor Viii ◽  
Factor Viii Activity

A Multicenter Pharmacosurveillance Study for the Evaluation of the Efficacy and Safety of Recombinant Factor VIII in the Treatment of Patients with Hemophilia A

1997 ◽  
Vol 78 (05) ◽  
pp. 1352-1356 ◽  
Author(s):  
Emel Aygören-Pürsün ◽  
Inge Scharrer ◽  
Keyword(s):  
Factor Viii ◽  
Hemophilia A ◽  
Parvovirus B19 ◽  
Subjective Evaluation ◽  
Recombinant Factor Viii ◽  
Fviii Inhibitor ◽  
Previously Treated Patients ◽  
Previously Treated ◽  
Bleeding Episodes ◽  
Recombinant Fviii

SummaryIn this open multicenter study the safety and efficacy of recombinant factor VIII (rFVIII) was assessed in 39 previously treated patients with hemophilia A (factor VIII basal activity ≤15%).Recombinant FVIII was administered for prophylaxis and treatment of bleeding episodes and for surgical procedures. A total of 3679 infusions of rFVIII were given. Efficacy of rFVIII as assessed by subjective evaluation of response to infusion and mean annual consumption of rFVIII was comparable to that of plasma derived FVIII concentrates. The incremental recovery of FVIII (2.4 ± 0,83%/IU/kg, 2.12 ± 0.61%/IU/kg, resp.) was within the expected range. No clinical significant FVIII inhibitor was detected in this trial. Five of 16 susceptible patients showed a seroconversion for parvovirus B19. However, the results are ambiguous in two cases and might be explained otherwise in one further case. Thus, in two patients a reliable seroconversion for parvovirus B19 was observed.

MODERN POSSIBILITIES OF SUBSTITUTION THERAPY AND HEMOPHILIA A PREVENTION IN CHILDREN

2021 ◽  
Vol 100 (2) ◽  
pp. 182-187
Author(s):  
P.A. Zharkov ◽  
Keyword(s):  
Factor Viii ◽  
Half Life ◽  
Hemophilia A ◽  
Safety Data ◽  
Residual Activity ◽  
Recombinant Factor Viii ◽  
Substitution Therapy ◽  
Life Effectiveness ◽  
Intravenous Injections ◽  
Prophylactic Use

Currently, the prophylactic use of factor VIII concentrate is the «gold standard» for treatment of an uncomplicated severe hemophilia A without inhibitors. However, there are a number of difficulties associated with frequent intravenous injections to maintain the activity of factor VIII above 1% in children and adolescents, which cannot but affect the adherence of patients to this type of treatment. The article discusses modern approaches to extend the half-life of recombinant factor VIII allowing to reduce the frequency of infusions and increase the residual activity of the deficient factor. On the example of efmoroctocog alpha, the first recombinant factor VIII concentrate registered in our country with a prolonged half-life, effectiveness and safety data of this class of drugs approved for use in children is presented.

Enhanced Half-Life Recombinant Factor VIII Concentrates for Hemophilia A: Final Results from Extension Studies

2021 ◽  
Author(s):  
Matteo Nicola Dario Di Minno ◽  
Alessandro Di Minno ◽  
Ilenia Calcaterra ◽  
Ernesto Cimino ◽  
Francesco Dell'Aquila ◽  
...  
Keyword(s):  
Factor Viii ◽  
Half Life ◽  
Hemophilia A ◽  
Recombinant Factor Viii ◽  
Factor Viii Concentrates

scholarly journals Postpartum Acquired Hemophilia: A Rare Cause of Postpartum Hemorrhage

2013 ◽  
Vol 2013 ◽  
pp. 1-2 ◽  
Author(s):  
Srikanth Seethala ◽  
Sumit Gaur ◽  
Elizabeth Enderton ◽  
Javier Corral
Keyword(s):  
Factor Viii ◽  
Hemophilia A ◽  
Factor Vii ◽  
Normal Vaginal Delivery ◽  
Factor Viii Inhibitor ◽  
Activity Levels ◽  
Factor Viii Activity ◽  
Acquired Hemophilia A ◽  
Acquired Hemophilia ◽  
Viii Inhibitor

A 36-year-old female started having postpartum vaginal bleeding after normal vaginal delivery. She underwent hysterectomy for persistent bleeding and was referred to our institution. An elevation of PTT and normal PT made us suspect postpartum acquired hemophilia (PAH), and it was confirmed by low factor VIII activity levels and an elevated factor VIII inhibitor. Hemostasis was achieved with recombinant factor VII concentrates and desmopressin, and factor eradication was achieved with cytoxan, methylprednisolone, and plasmapheresis.

Sign in / Sign up

Export Citation Format

Share Document