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Published on: February 27, 2026
International comparative field study of N8 evaluating factor VIII assay performance
D Viuff1, Tw Barrowcliffe, T Saugstrup
1Novo Nordisk A/S, Medical and Science, Haemophilia, Søborg, Denmark. dviu@novonordisk.com
Summary
This study compared N8, a truncated Factor VIII (FVIII) product, with Advate® using different assays. N8 demonstrated reliable measurement in plasma, similar to Advate®, across various concentrations without needing a specific N8 standard.
Area of Science:
- Pharmacology
- Biotechnology
- Clinical Diagnostics
Background:
- Discrepancies in clotting assays pose challenges for B-domain deleted Factor VIII (FVIII) products.
- N8 is a novel B-domain truncated FVIII product developed by Novo Nordisk.
Purpose of the Study:
- To compare the performance of N8 and Advate® in simulated postinfusion samples using one-stage and chromogenic assays.
- To assess the reliability of measuring N8 in plasma without a specific standard.
Main Methods:
- An international, multicentre, randomized, and blinded field study.
- Comparison of N8 and Advate® using one-stage clotting assays and chromogenic assays.
- Analysis of FVIII levels at target concentrations of 0.03, 0.2, 0.6, and 0.9 IU mL(-1).
Main Results:
- Both N8 and Advate® performed similarly in the one-stage assay across all tested concentrations.
- Chromogenic assays showed a tendency towards higher N8 values compared to Advate®.
- The ratio of chromogenic/one-stage potencies was concentration-dependent, ranging from 0.66 to 1.30.
- Assay variability was similar for both FVIII products.
Conclusions:
- N8 can be reliably measured in plasma using standard assays without requiring a dedicated N8 standard.
- The study validates the use of existing assay methodologies for N8 monitoring.
- Findings support the clinical utility of N8 as a therapeutic option.
