Kinetics of the interaction between anti‐FVIII antibodies and FVIII from therapeutic concentrates, with and without von Willebrand factor, assessed by surface plasmon resonance

Abstract

The presence of VWF in plasma-derived FVIII (pdFVIII/VWF) products has been pointed out as a key difference with recombinant FVIII (rFVIII) products with regard to immunogenicity. A Surface Plasmon Resonance (SPR) study was designed to characterize in detail the interaction between anti-FVIII (IgGs) from a severe haemophilia A patient, and FVIII from concentrates of different sources. Full-length rFVIII (preincubated or not with purified VWF), B domain-deleted (BDD)-rFVIII and pdFVIII/VWF were analysed. To ensure reproducible conditions for accurate determination of kinetic constants, a capture-based assay format was developed using protein G surfaces for specific and reversible coupling of endogenous anti-FVIII antibodies. Concentration ranges (nm) of FVIII products tested were 9-0.03 (rFVIII) and 6-0.024 (pdFVIII/VWF). The association with antibodies was monitored for 3-5 min, whereas dissociation of the complex was followed for 5-20-240 min. A strong interaction of rFVIII and BDD-rFVIII with patient's IgG was detected with the K (D) values in the low picomolar range (5.9 ± 3.0 and 12.7 ± 6.9 pm, respectively) and very slow dissociation rates, while pdFVIII/VWF showed only marginal binding signals. The VWF complexed rFVIII displayed reduced binding signals compared with uncomplexed rFVIII, but the K (D) was still in the picomolar range (4.1 ± 1.9 pm) indicating insufficient complex formation. rFVIII, alone or bound to exogenously added VWF, showed high affinity for anti-FVIII IgGs from a severe haemophilia A patient whereas pdFVIII/VWF did not. These results are in agreement with those studies that point towards rFVIII concentrates to be more immunogenic than pdFVIII concentrates.

Plasma‐derived FVIII/VWF complex shows higher protection against inhibitors than isolated FVIII after infusion in haemophilic patients: A translational study

“…Our ex vivo studies demonstrated, for the first time in the clinical setting, that plasma from patients who received pdFVIII/VWF consistently showed less inhibitory reactivity regardless of the type of rFVIII product they received. Previous studies performed in vitro on different FVIII‐containing products have shown that the rFVIII concentrates invariably contained a fraction of factor FVIII related antigen (FVIII:Ag) molecules (approximately 20%) which was unable to associate with VWF 28,29 . Results of the present clinically oriented ex vivo study confirmed a high level of correspondence with those of previous in vitro studies 14,30 (refer to Supporting information for indirect comparisons).…”

Novel investigations on the protective role of the FVIII/VWF complex in inhibitor development

“…A recent study used surface plasmon resonance to characterize the interaction between human anti‐FVIII IgG inhibitors and FVIII in concentrates from different sources . Although measuring an antigen–antibody interaction by surface plasmon resonance is a complex process, it has a strong validation method.…”

“…rFVIII , recombinant FVIII; BDD rFVIII , B domain deleted rFVIII ; rFVIII /VWF, rFVIII incubated with von Willebrand factor (VWF); pdFVIII/VWF, plasma‐derived FVIII containing VWF. Adapted from .…”

“…The antigen–antibody reaction with uncomplexed full‐length rFVIII was used as the reference value. Adapted from .…”

The Current Role of Bone Marrow Transplantation in the Treatment of Hemophilia A

“…The high purity concentrates are manufactured using monoclonal antibodies to factor VIII or vWF. These products underwent multiple purification steps including heat treatment to reduce risk of viral transmission [20]. It was revealed in the 1990s, that one lot of pdFVIIIC to be associated with high risk of appearance of factor VIII inhibitor in patients who were extensively under infusion of pdFVIIIC.…”