TABLE 5.
Longitudinal pharmacokinetic–pharmacodynamic model parameters
| Parameter | Variable | Estimate | RSE | Between‐subject variability |
|---|---|---|---|---|
| Placebo response (PASI reduction from baseline) | Pmax | 19% | 7.0% | 199% |
| Maximum tildrakizumab effect (PASI reduction from baseline) | Emax | 100% | ‐ | ‐ |
| Potency (μg mL−1) | EC50 | 0.25 | 4.8% | 183% |
| Healing time (wk) | t1/2 kout | 4.2 | 2.6% | 86% |
| Drug effect onset (wk) | 3 × t1/2 ktr | 1.7 | 4.0% | 98% |
| Placebo response at 131 kg (%) a | ‐ | 23% | ‐ | ‐ |
| Placebo response at 56 kg (%) a | ‐ | 14% | ‐ | ‐ |
EC50, drug concentration needed to achieve 50% of the maximum drug effect; Emax, maximum drug effect; kout, first‐order rate constant for the loss of the response; ktr, transit rate constant; PASI, Psoriasis Area and Severity Index; Pmax, maximum placebo response; RSE, relative standard error; t1/2, half‐life.
a
Body weight levels (56 and 131 kg) represent the 5th and 95th percentiles, respectively.