Population pharmacokinetics of ponesimod and its primary metabolites in healthy and organ-impaired subjects

Clinical Pharmacokinetics of Ponesimod, a Selective S1P1 Receptor Modulator, in the Treatment of Multiple Sclerosis

Ponesimod, a selective, rapidly reversible, and orally active, sphingosine-1 phosphate receptor (S1P) modulator, is indicated for the treatment of relapsing-remitting multiple sclerosis (RRMS). The clinical pharmacokinetics (PK) and pharmacodynamics (PD) of ponesimod was studied in 16 phase I, one phase II, and one phase III clinical studies. Ponesimod population PK was characterized by an open two-compartment disposition model with a terminal half-life of 33 h (accumulation factor of 2- to 2.6-fold), and fast and almost complete oral absorption (absolute oral bioavailability: 84%), reaching peak plasma and blood concentrations within 2-4 h. Ponesimod is highly metabolized, and the parent compound along with its two major (non-clinically active) metabolites are mainly excreted in the feces (recovery: 57.3-79.6%) and to a lesser extent in the urine (recovery: 10.3-18.4%). Additionally, the population PKPD model characterized the ponesimod effects on heart rate: a transient, dose-dependent decrease in heart rate in the first days of dosing, that is mitigated by administering the first doses of ponesimod treatment using a gradual up-titration schedule, before reaching the daily maintenance dose of 20 mg. This selected maintenance dose has been shown to be superior in reducing annualized relapse rate (ARR) when compared with teriflunomide in a pivotal phase III study. Furthermore, a dose-dependent reduction of peripheral lymphocyte counts that is sustained with continued daily oral dosing of ponesimod and is rapidly (4-7 days) reversible upon drug discontinuation has been characterized with an indirect response model.

Modeling clinical efficacy of the S1P receptor modulator ponesimod in psoriasis

BACKGROUND

Ponesimod is currently the only S1P receptor modulator studied in psoriasis. In a dose-finding study, the active doses showed similar efficacy.

OBJECTIVE

Prediction of efficacy at lower doses to aid clinical phase 3 planning with respect to dose selection, duration of treatment, and patient inclusion criteria based on pharma-co-kinetic/pharmacodynamic (PK/PD) modeling and simulation.

METHODS

The dose-finding study treated 326 patients (67 on placebo, 126 on 20mg, and 133 on 40mg) over 16 weeks. PK/PD modeling of steady-state trough concentrations and longitudinal PASI scores was employed to characterize data and simulate scenarios.

RESULTS

PASI score continually decreased with time on ponesimod treatment, reaching a plateau at 16 weeks. Absolute and relative (percent) PASI score change was larger in patients with higher PASI score at baseline. Doses below 10mg were predicted to show lower efficacy than doses of 10mg and higher.

CONCLUSION

Concentration-response modeling was able to predict the efficacy of doses that were not studied. In psoriasis patients, a dose of 10mg (not administered in the study) was predicted to show efficacy similar to 20mg. Disease status (PASI score at baseline) as study inclusion criterion has pronounced influence on study outcome.