title: Pharmacokinetic/pharmacodynamic analyses of chymase inhibitor SUN13834 in NC/Nga mice and prediction of effective dosage for atopic dermatitis patients.
abstract: A chymase inhibitor SUN13834 has been shown to improve skin condition in animal models for atopic dermatitis. In the present study, effective dosages of SUN13834 for atopic dermatitis patients were predicted by pharmacokinetic/pharmacodynamic (PK/PD) analyses of SUN13834 in NC/Nga mice, which spontaneously develop atopic dermatitis-like skin lesions. For the PK/PD analyses, we utilized the minimum effective plasma concentration of unbound SUN13834 in late-phase reaction of trinitrochlorobenzene (TNCB)-induced biphasic dermatitis in mice, based on the assumption that the minimum effective plasma concentrations are the same among the two animal models. In late-phase reaction of biphasic dermatitis, SUN13834 was most effective when its plasma concentration was highest at the elicitation, and the minimum effective plasma concentration of unbound SUN13834 at the elicitation was calculated to be 0.13-0.2 ng/mL. Oral administration of SUN13834 improved dermatitis in NC/Nga mice at 15 mg/kg (twice a day; bid) and 30 mg/kg (once a day; qd), but not at 60 mg/kg (every other day; eod). At the three dosages, the duration times over the plasma level of 0.13-0.2 ng/mL were 16.1-20.3, 10.7-12.2 and 7.8-8.8h, respectively, suggesting an importance of maintenance of the minimum effective plasma concentration for at least about 10-12h. The clinical effective dosage predicted in this paper is also discussed in relation to a recently conducted Phase 2a study.
authors.affiliation: Asubio Pharma Co, Limited 6-4-3, Minatojima-Minamimachi, Chuo-ku, Kobe 650-0047, Japan.
authors.forename: Atsuto
authors.initials: A
authors.lastname: Ogata
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Fujieda
authors.forename: Maki
authors.initials: M
authors.lastname: Terakawa
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Muto
authors.forename: Taisaku
authors.initials: T
authors.lastname: Tanaka
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Maruoka
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Nagahira
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Fukuda
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Tomimori
authors.forename: Naohiro
authors.initials: N
authors.lastname: Watanabe
mesh_terms: D000284:Administration, Oral; D000818:Animals; D001381:Azepines / Q000008:administration & dosage* / Q000493:pharmacokinetics; D053818:Chymases / Q000378:metabolism*; D017322:Clinical Trials, Phase II as Topic; D003876:Dermatitis, Atopic / Q000139:chemically induced / Q000188:drug therapy* / Q000201:enzymology; D004198:Disease Susceptibility; D054796:Drug Dosage Calculations; D004791:Enzyme Inhibitors / Q000008:administration & dosage* / Q000493:pharmacokinetics; D006801:Humans; D051379:Mice; D008815:Mice, Inbred Strains; D010853:Picryl Chloride / Q000008:administration & dosage; D012867:Skin / Q000187:drug effects* / Q000473:pathology
chemical_list: C538783:6-(5-chloro-2-methoxybenzyl)-4-alarkylaminocarbonyl-1,4-diazepane-2,5-dione; D001381:Azepines; D004791:Enzyme Inhibitors; D053818:Chymases; D010853:Picryl Chloride