Table 2. Mepolizumab population pharmacokinetic parameter estimates from the intravenous and subcutaneous population pharmacokinetic analyses.
| Parameters (IV) | Estimate (95% CI) | BSV |
|---|---|---|
| CL (L/day) | 0.210 (0.189 – 0.232) | 23.3% |
| Vc (L) | 3.60 (3.19 – 4.05) | 17.2% |
| Vp (L) | 3.56 | NA |
| Kcp (/day) | 0.280 (0.214 – 0.367) | 60.6% |
| Kpc (/day) | 0.283 (0.233 – 0.344) | NA |
| RESIDUAL | 0.214 (0.142 – 0.286) | WSB (95% CI) 21.6% (14.3 – 29.2) |
| Parameters (SC) | ||
| CL/F (L/day) | 0.310 (0.275 – 0.349) | 57.7% |
| Vc/F (L) | 4.57 (4.02 – 5.20) | 59.3% |
| Vp/F (L) | 4.53 | NA |
| Kcp (/day) | 0.280 (fixed) | NA |
| Kpc (/day) | 0.283 (fixed) | NA |
| KA (/day) | 0.194 (0.155 – 0.242) | 87.2% |
| RESIDUAL | 0.333 (0.279 – 0.387) | WSB (95% CI) 34.2% (28.5 – 40.1) |
CL = plasma clearance; Vc = volume of the central compartment; Vp = volume of the peripheral compartment; Kcp = rate constant (from central to peripheral compartment); Kpc = rate constant (from peripheral to central compartment); CL/F = apparent clearance; Vc/F = apparent volume of the central compartment; Vp/F= apparent volume of the peripheral compartment; KA = absorption rate constant; NA = not applicable; CI = confidence interval; BSV = between-subject variability; WSB = within-subject variability. Vp, Vp/F and WSB (95% CI) were calculated post-hoc. Vp and Vp/F estimates are derived from their composite parameters. Residual error model: Y = F+F×θi×(εi) with εi = 1; 95% CI = estimate ± 1.96 × SE; SE = standard error; %CV = 100 × SQRT(exp(x)-1) with x = ETA or x = (θi×(εi))2; ETA = variance.