Abstract Number: PB0537
Meeting: ISTH 2020 Congress
Background: Factor VIII (FVIII) levels are measured by one-stage clotting assay (OSA) and FVIII OSA is based on APTT method using activator and factor VIII-deficient plasma (F8DP). A variation of the reagents and their combination has been an issue but was not fully evaluated for potency testing of FVIII products.
Aims: We aimed to evaluate the variation of OSA results in FVIII product-spiked plasma using various kinds of combination of activator and F8DPs.
Methods: FVIII OSAs were performed using following reagent combinations: two immunodepleted F8DP (F8DP-1/-2) and one of congenital F8DP (F8DP-3) was used in combination with APTT reagents; Actin (ACT), Actin FSL (FSL), Thrombocheck APTT-SLA (SLA) and Pathromtin SL (PSL). The combination of ACT/F8DP-3 and PSL/F8DP-3 showed poor internal control results and exclude in this study. Total of eleven combinations were evaluated. Octocog alpha, octocog beta (Bayer), rurioctocog alpha (Takeda), turoctocog alpha (Novo Nordisk), efraloctocog alpha (Sanofi)and rurioctocog alpha pegol (Takeda) were spiked into congenital FVIII-deficient plasma (George King Bio-Medical) to reach 0.80, 0.20 and 0.05 IU/mL based on the labelled vial potency.
Results: The mean FVIII activity (FVIII:C) and coefficient of variations (CVs) of spike recoveries were shown in Table 1. In all reagent combinations, higher CVs were shown in lower concentration of 0.05 IU/mL. The FVIII:C and CVs were similar in octocog alpha/beta, turoctocog alpha, and rurioctocog alpha pegol. The minimal CV was observed in turoctocog alpha-spiked plasma. Meanwhile, for comparison of APTT reagents, ACT and FSL showed higher FVIII:C than SLA and PSL. FSL/F8DP-1 showed the highest CV of 27.8% among FVIII products whereas the other reagent combinations resulted in CVs < 20%.
| FVIII products | Nominal concentration (IU/mL) | ||
| 0.80 | 0.20 | 0.05 | |
| Ocotocog alpha | 1.17±0.21 (18.2) | 0.31±0.05 (17.4) | 0.09±0.02 (21.9) |
| Ocotocog beta | 1.17±0.17 (14.4) | 0.31±0.04 (14.2) | 0.09±0.02 (19.2) |
| Rurioctocog alpha | 0.96±0.14 (14.8) | 0.25±0.03 (13.5) | 0.07±0.01 (18.6) |
| Turoctocog alpha | 1.10±0.13 (12.1) | 0.29±0.03 (9.7) | 0.08±0.01 (15.2) |
| Efraloctocog alpha | 1.59±0.28 (17.9) | 0.42±0.05 (12.8) | 0.12±0.02 (16.7) |
| Rurioctocog alpha pegol | 1.19±0.17 (14.4) | 0.31±0.05 (17.2) | 0.09±0.02 (22.2) |
[The mean FVIII activity and CVs of each product measured by eleven kinds of OSA. The FVIII:C (IU/mL) results were shown as mean±SD (CV%).]
Conclusions: The CVs of spike recovery were within 25%. The FVIII:C variation due to OSA reagents was significant in lower FVIII concentration. The potency of FVIII depended on a combination of APTT reagent and F8DP.
To cite this abstract in AMA style:
Suzuki A, Suzuki N, Kanematsu T, Okamoto S, Tamura S, Kojima T, Matsushita T. Impact of Combination of Factor VIII-Deficient Plasma and Activator in One-Stage Clotting Assay on Potency Testing of Factor VIII Products [abstract]. Res Pract Thromb Haemost. 2020; 4 (Suppl 1). https://abstracts.isth.org/abstract/impact-of-combination-of-factor-viii-deficient-plasma-and-activator-in-one-stage-clotting-assay-on-potency-testing-of-factor-viii-products/. Accessed September 29, 2023.« Back to ISTH 2020 Congress
ISTH Congress Abstracts - https://abstracts.isth.org/abstract/impact-of-combination-of-factor-viii-deficient-plasma-and-activator-in-one-stage-clotting-assay-on-potency-testing-of-factor-viii-products/