title: Population pharmacokinetics and pharmacodynamics of ponesimod, a selective S1P1 receptor modulator.
abstract: Ponesimod (ACT-128800), a reversible, orally active, selective S1P1 receptor modulator, prevents the egress of lymphocytes from the lymph node into the systemic circulation. It is currently in clinical development for the treatment of relapsing multiple sclerosis. Modulation of circulating lymphocytes serves as biomarker of efficacy and safety, such that the quantitative characterization of the pharmacokinetic/pharmacodynamic (PK/PD) relationship guides the clinical development of the compound. The availability of a variety of doses, dosing regimens, and treatment durations permitted estimation of the pharmacokinetics characterized by an absorption lag time followed by a sequential zero/first-order absorption and two compartments with first-order elimination. The PD are modeled as an indirect-effect model with rates of appearance and disappearance of lymphocytes in blood with a circadian rhythm and a drug effect on the rate of appearance. The model suggests a circadian variation of 9% and a maximum inhibition of 86% of total lymphocyte count with high doses at steady state. It was instrumental for the selection of doses for subsequent studies that confirmed the effect plateau in total lymphocyte count at approximately 0.5 × 10(9) counts/L.
authors.affiliation: Department of Clinical Pharmacology, Actelion Pharmaceuticals Ltd, Gewerbestr. 16, 4123, Allschwil, Switzerland, andreas.krause@actelion.com.
authors.forename: Andreas
authors.initials: A
authors.lastname: Krause
authors.forename: Patrick
authors.initials: P
authors.lastname: Brossard
authors.forename: Daniele
authors.initials: D
authors.lastname: D'Ambrosio
authors.forename: Jasper
authors.initials: J
authors.lastname: Dingemanse
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001835:Body Weight / Q000502:physiology; D002940:Circadian Rhythm / Q000502:physiology; D005260:Female; D006801:Humans; D007408:Intestinal Absorption; D018655:Lymphocyte Count; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D009103:Multiple Sclerosis / Q000188:drug therapy / Q000378:metabolism; D011153:Population; D049349:Receptors, Lysosphingolipid / Q000187:drug effects*; D013844:Thiazoles / Q000493:pharmacokinetics* / Q000494:pharmacology*; D055815:Young Adult
chemical_list: D049349:Receptors, Lysosphingolipid; D013844:Thiazoles; C550169:ponesimod