Abstract Number: PB1152
Meeting: ISTH 2020 Congress
Background: Adynovi® contains rurioctocog alfa pegol, a novel recombinant factor VIII (rFVIII) indicated for the treatment of haemophilia A. Since Adynovi® structurally strongly differs from other rFVIII proteins, the optimal assay for measurement of Adynovi® must be determined.
Aims: In this study, we compared two one stage clotting assays (OSCA) with two chromogenic assays (CA) for the FVIII activity measurement in patients treated with Adynovi®. Secondly, we investigated the Bethesda assay for the quantification of anti-FVIII against Adynovi®.
Methods: Adynovi® was diluted in FVIII deficient plasma with end concentrations of 2.5%, 5%, 10%,50%, 100% and 200%. FVIII: C was measured in the dilution series and samples of a patient treated with Adynovi® therapy (N=9). Four different methods were tested, including OSCA with C.K. PREST® and PTT-A reagents, and CA with TriniCHROM Factor VIII: C and BIOPHEN FVIII: C on STA-R EVO. In addition, anti-FVIII inhibitor against Adynovi® was measured in samples (N=2) of a patient chronically treated with Adynovi® who developed anti-FVIII (1.3-6.2BE). The classical Bethesda assay was applied using both 100% Unicalibrator and 100% Adynovi® as reference.
Results: For FVIII:C measured with OSCA, an acceptable recovery of -13 to 9% was observed for C.K. PREST and -11 to 8% for PTT-A reagent for Adynovi® concentrations 5-200%. In contrast, we observed a large positive deviation from the expected value with both CA (14-30% with TriniCHROM Factor VIII: C reagent and 28-63% with BIOPHEN FVIII: C reagent). In Adynovi® patient samples, we also report a large difference between OSCA and CA (10-150% for TriniCHROM Factor VIII: C and 22-110% for BIOPHEN FVIII: C reagent). For quantification of anti-FVIII, only a small difference of 0.3% was observed between the application of 100% unicalibrator and 100% Adynovi®as reference for the Bethesda assay.
Conclusions: The OSCA is the preferred method to monitor FVIII:C in patients treated with Adynovi®. The Bethesda assay yields comparable results for quantification of anti-FVIII inhibitor against Adynovi® using 100% Unicalibrator and 100% Adynovi® as reference.
To cite this abstract in AMA style:Heireman L, Devreese K. Determining the Optimal Method for FVIII:C and Anti-FVIII Quantification in a Patient Treated with Adynovi® who Developed Anti-FVIII during Treatment [abstract]. Res Pract Thromb Haemost. 2020; 4 (Suppl 1). https://abstracts.isth.org/abstract/determining-the-optimal-method-for-fviiic-and-anti-fviii-quantification-in-a-patient-treated-with-adynovi-who-developed-anti-fviii-during-treatment/. Accessed December 11, 2023.
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