Table 1.
Parameter estimates of the final population PK model and bootstrap (95% non-parametric confidence interval) for SV, SVA, HMSV, HMSVA, and DHSV
| Drug | Parameters | Structural model | Between subject variability (BSVb) | ||
|---|---|---|---|---|---|
| Estimatea | Bootstrap | Estimate [shrinkage(%)] | Bootstrap | ||
| SV | D1 (h−1) | 0.069 | 0.064–0.073 | – | – |
| D2 (h−1) | 0.39 | 0.34–0.42 | 2.07 [17] | 1.75–2.27 | |
| ka1 (h−1) | 0.030 | 0.027–0.032 | – | – | |
| ka2 (h−1) | 0.41 | 0.38–0.46 | 0.41 [0.5] | 0.38–0.45 | |
| BA* | 0.78 | 0.70 – 0.89 | – | – | |
| ALAG (h) | 0.18 | 0.17–0.21 | 1.70 [13] | 1.40–2.09 | |
| CLSLe/F (L/h) | 1300 | 1210–1450 | 0.63 [3] | 0.53–0.71 | |
| VSL/F (L) | 110 | 98.7–114 | 2.17 [27] | 1.59–2.25 | |
| SVA | CLLA/VSVA (h−1) | 0.043 | 0.04–0.046 | 0.96 [9] | 0.76–1.02 |
| CLSVAe/VSVA (h−1) | 0.13 | 0.11–0.14 | 0.79 [25] | 0.60–0.81 | |
| θ561: c.521T>C on VSVA | − 0.37 | − 0.38 to − 0.35 | – | – | |
| θ562: c.521T>C on CLLA | 0.93 | 0.86–1.04 | – | – | |
| HMSV | CLLH/VHSV (h−1) | 16.1 | 15–21.5 | 0.26 [32] | 0.23–0.28 |
| CLEmax/VHSV (nM/h) | 660 | 637–967 | – | – | |
| CLEC50 (nM) | 20 | 17.8–22.8 | 0.67 [6] | 0.58–0.74 | |
| γ | 0.86 | 0.83–0.87 | – | – | |
| HMSVA | CLAH/VHSVA (h−1) | 0.48 | 0.39–0.5 | 0.33 [60] | 0.27–0.36 |
| CLHSVAe/VHSVA (h−1) | 4.91 | 4.6–5.1 | 0.18 [47] | 0.12–0.19 | |
| CLHSVHSVA/VHSVA (h−1) | 0.55 | 0.52–0.62 | 0.51 [4] | 0.45–0.56 | |
| θAGE1: age (Fra) on CLHSVAe | 1 (fixed) | – | – | – | |
| θAGE2: age (50%) on CLHSVAe (year) | 5.34 | 4.9–5.5 | – | – | |
| DHSV | CLLD/VDHSV (h−1) | 4.11 | 3.8–5.0 | 0.29 [34] | 0.23–0.29 |
| CLDHSe/VDHSV (h−1) | 12.9 | 12.3–14.2 | 0.28 [42] | 0.22–0.29 | |
| θAGE3: age (Fra) on CLDHSe | 0.90 | 0.83–0.94 | – | – | |
| θAGE4: age (50%) on CLDHSe (year) | 6.3 | 5.9–6.6 | – | – | |
| Residual Variabilityc | |||||
| SV | eps1SV | – | – | 0.38 | 0.33–0.44 |
| eps2SV | 0.32 | 0.28–0.35 | |||
| eps3SV | 0.30 | 0.29–0.33 | |||
| mSV | 0.012 | 0.011–0.012 | |||
| SVA | eps1SVA | 0.26 | 0.23–0.29 | ||
| eps2SVA | 0.16 | 0.13–0.16 | |||
| mSVA | 0.22 | 0.19–0.24 | |||
| HMSV | eps1HMSV | 0.29 | 0.27–0.34 | ||
| eps2HMSV | 0.24 | 0.22–0.28 | |||
| eps3HMSV | 0.12 | 0.11–0.28 | |||
| mHMSV | 0.0001 (fixed) | – | |||
| HMSVA | eps1HMSVA | 0.18 | 0.16–0.20 | ||
| eps2HMSVA | 0.1 | 0.095–0.11 | |||
| mHMSVA | 0.0001 (fixed) | – | |||
| DHSV | eps1DHSV | 0.24 | 0.21–0.27 | ||
| eps2 DHSV | 0.21 | 0.19–0.23 | |||
| eps3 DHSV | 0.086 | 0.08–0.09 | |||
| mDHSV | 0.0001 (fixed) | – | |||
*F1 = 1/(1 + BA), F2 = BA/(1 + BA)
aPopulation parameter estimates for a typical individual in the study, 14 years old, 80 kg and homozygous variant CC genotype for the rs4149056
bBSV is expressed as CV (coefficient of variation) calculated as
cResidual error variability for the analytes were based on the double exponential error model for log-transformed data with time dependency for some analytes. ln(y) = ln(f + m) + (f/(f + m)ε1 + (m/(m + f))ε2 where y is the observed concentration, f is the model prediction, m is a positively constrained parameter, and ε1 and ε2 are random errors, assumed to be normally distributed with means of zero and variance of eps1 and eps2, respectively. m is estimated or fixed to an estimate around or lower than the LLOQ in order to minimise bias
SV—eps1SV and eps2SV correspond to 0–2 h and 2–8 h for ε1 and eps3SV and mSV to ε2 and m, respectively. SVA—eps1SVA, eps2SVA, and mSVA correspond to ε1, ε2, and m respectively. HMSV—eps1HMSV and eps2HMSV correspond to 0–2 h and 2–8 h for ε1 and eps3HMSV and mHMSV to ε2 and m, respectively. HMSVA—eps1HMSVA, eps2HMSVA, and mHMSVA correspond to ε1, ε2, and m, respectively. DHSV—eps1DHSV and eps2DHSV correspond to 0–2 h and 2–8 h for ε1 and eps3DHSV and mDHSV to ε2 and m, respectively