91 LC-MS/MS-method validation quantifying emicizumab Cross-validation study A total of 77 samples obtained from 41 patients were used for cross-validation (Table 3). Most patients were male with a diagnosis of severe congenital haemophilia A. The mean age at sampling was 28 years (range 0-78 years) and the mean treatment week at sampling was 20 weeks (range 1-133 weeks). The mean plasma concentration of emicizumab measured with LC-MS/MS was 49 µg/mL (range 11−106 µg/mL), and also 49 µg/mL (range 8−104 µg/mL) when measured with mcOSA. Table 3. Patient characteristics from samples in cross validation. Total number of patients = 41 Number of patients Severe congenital HA 38a Male 40 Total number of samples = 77 Number of samples mean min max SD Emicizumab concentration (µg/mL)b 77 49 11 106 23 Age at sampling (year) 77 28 0 79 26 Treatment week of sampling 77 20 1 133 29 Albumin concentration - Measured (g/L) - Not measured 39 38 42.0 32.1 47.8 4.3 aFVIII titer - >0.5 BU/mL - ≤0.5 BU/mL 19 58 549 0.6 2790 951 FVIII in sample - Presentc - Absent 19 58 a Remaining patients: one woman with acquired HA (three samples); two men with moderate HA (two samples). b Measured with LC-MS/MS. c FVIII:C was not quantified in presence of emicizumab. Abbreviations: aFVIII: anti-FVIII antibodies (inhibitors); BU: Bethesda Units; FVIII: coagulation factor VIII; FVIII:C: factor VIII activity; HA: haemophilia A; SD: standard deviation. The correlation between observations of the emicizumab concentrations measured with mcOSA and the LC-MS/MS method, using weighted Deming regression, is depicted in Figure 1. The slope of the regression line was 1.02 (95% CI 0.891−1.144) with an intercept of -1.61 (95% CI -7.18−3.95) (Pearson’s r = 0.986). The line of identity, with a regression slope of 1, lies within the 95% CI of the weighted Deming regression line (Figure 1). 5
RkJQdWJsaXNoZXIy MTk4NDMw