Table 2.
Parameter estimates
| Parameter (units) | Estimate | RSE (%) |
|---|---|---|
| V/F (l) | 10.8 | 20 |
| CL/F (l day−1) | 0.32 | 5 |
| SX_CL | 0.32 | 34 |
| WT_CL | 0.81 | 28 |
| ka (day−1) | 0.28 | 4 |
| kin (mg l−1 day−1) | 22 | 15 |
| kout (day−1) | 0.875 | (Fixed) |
| C50 (mg l−1) | 3.6 | 26 |
| DAS280 | 5.5 | 3 |
| IC50 (mg l−1) | 11.0 | 16 |
| ωVd (%) | 92 | 16 |
| ωCL (%) | 17 | 27 |
| ωKin (%) | 65 | 18 |
| ωKout (%) | – | – |
| ωC50 (%) | 88 | 27 |
| ωImax (%) | 11 | 32 |
| ωIC50 (%) | 71 | 17 |
| σprop_PK (%) | 24 | 9 |
| σadd_CRP (mg l−1) | 1.6 | 29 |
| σprop_CRP (%) | 52 | 10 |
| σadd_DAS | 68 | 8 |
The value of kout was fixed, and no interindividual variability was estimated for this parameter.
The RSE (%) was obtained as follows:RSE = (estimate/standard error) × 100. Abbreviations are as follows: C50, adalimumab concentration leading to a 50% decrease of kin; CL/F, apparent clearance; CRP, C-reactive protein; DAS280, estimated baseline disease activity score in 28 joints; IC50, adalimumab concentration leading to a decrease in DAS280 of 50%; ka, first-order absorption rate constant; kin, zero-order CRP input; kout, first-order CRP output; PK, pharmacokinetics; RSE, relative standard error; SX, sex; Vd/F, apparent volume of distribution; WT, bodyweight; σadd, additive error standard deviation; σprop, proportional error standard deviation; ω, interindividual standard deviation.