Abstract Number: PB0345
Meeting: ISTH 2021 Congress
Background: Recombinant FVIIa has been shown to be efficacious for treatment of bleeding in congenital and acquired hemophilia A with inhibitor and in congenital FVII deficiency as well as in Glanzmann’s thrombasthenia. As for other recombinant therapeutic proteins, administration of rFVIIa may induce the development of anti-FVIIa antibody that could be associated with a decrease of the treatment efficacy. Very limited data are available on development of anti-FVIIa antibody. Surveillance of rFVIIa immunogenicity is then required.
Aims: To develop a method for measuring the anti-FVIIa antibody in patients treated with rFVIIa.
Methods: An ELISA bridging method has been developed by using rFVIIa (NovoSeven, Novo Nordisk) for both coating and detection. The best experimental conditions were a high-density of immobilized antigen, acid dissociation and long incubation time with plasma samples.
Commercial (Affinity Biological) FVII deficient plasma and FVII Inhibitor plasma (4.5 and 67.1 BU) have been used as negative and positive controls with sheep anti-human FVII IgG used as a reference standard.
Several experiments have been performed and a significant improvement in IgG recovery has been achieved with FVII depleted plasma containing 1 ug/mL rFVIIa and 1.25 or 0.6 ug/mL of anti-human FVII IgG, by the acid dissociation and the long incubation time (figure 1).
By increasing the concentration of immobilized antigen from 1 to to 5ug/mL further improvement has been achieved in the IgG recovery (figure 2).
Conclusions: Monitoring the patient immune-response to a therapeutic protein is important to assess the drug efficacy and its immunogenicity. However, the antibody detection could be complicated by the presence of the antigen in the plasma sample. Here we describe a novel method unaffected by the presence of rFVIIa that could detect the incidence of the anti-FVIIa antibodies during the treatment with recombinant FVIIa.
To cite this abstract in AMA style:Valsecchi C, Schiavone L, Behrouz H, Ahsani Z, Saadatirad A, Peyvandi F. Development of a New ELISA Method for Anti-FVIIa Antibody Measurement [abstract]. Res Pract Thromb Haemost. 2021; 5 (Suppl 1). https://abstracts.isth.org/abstract/development-of-a-new-elisa-method-for-anti-fviia-antibody-measurement/. Accessed September 24, 2021.
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