INNOVANCE Antithrombin

INNOVANCE Antithrombin is a chromogenic assay that automatically measures functionally active antithrombin in blood plasma samples. It is used to diagnose antithrombin deficiency and to monitor antithrombin activity levels to guide dosing of the drug QFITLIA (fitusiran) in hemophilia A or B patients aged 12 years and older.

Both the proposed device and predicate use chromogenic methodology to quantify antithrombin III in human citrated plasma on automated coagulation analyzers. The proposed device is entirely liquid-phase reagents with 48-hour on-board stability, whereas the predicate uses lyophilized components with 24-hour stability. Both measure the same analyte in the same units (% of norm) with comparable linearity and precision performance.

Studies followed CLSI document EP05-A3 for precision evaluation, CLSI EP07 for interference testing, and CLSI EP17-A2:2012 for limit of quantitation determination. Sample storage and handling referenced CLSI document H21-A52.

The proposed device shares the same regulatory classification, intended clinical use (diagnosis and monitoring of antithrombin deficiency), test principle (chromogenic assay at 405 nm), sample type, analyte, measurement units, and comparable analytical performance (precision, linearity, and interference profiles) as the predicate. The differences in physical form, on-board stability, and reagent composition do not alter intended use or safety and efficacy. Clinical validation in the ATLAS-OLE study of 213 hemophilia patients confirmed that INNOVANCE Antithrombin successfully achieved target antithrombin levels for QFITLIA dosing guidance.