title: An investigation of the correlation between blood concentration of mizoribine and its efficacy in treatment of rheumatoid arthritis based on indices of drug survival and improvement in DAS28-CRP.
abstract: OBJECTIVE
  The efficacy of mizoribine (MZR) in treatment of rheumatoid arthritis (RA) was retrospectively investigated in terms of drug survival, improvement in Disease Activity Score-28 (DAS28)-C-reactive protein (CRP), and blood MZR concentration obtained 3 h after dosing (MZR-C3).
  
  
  METHODS
  To compare the efficacy of MZR administered via different regimens, the subjects were divided into 2 groups: those receiving a single dose of MZR at 100-150 mg every other day (group A) and those receiving 2 or 3 divided doses of the drug on consecutive days, which is the usual dosing method of the drug (group B).
  
  
  RESULTS
  Group A had significantly higher MZR-C3 levels compared with group B, as well as significantly greater improvement in DAS28-CRP. Moreover, drug survival was significantly longer in group A. The primary regression equation suggested that the effective blood MZR concentration in RA treatment is MZR-C3 of 1.47 µg/mL or more.
  
  
  CONCLUSIONS
  The results of the present study indicate that it is possible to increase the efficacy of MZR in a blood concentration-dependent manner, and also to control RA over a prolonged period, using single administration of MZR on alternate days at an increased dose.
authors.affiliation: Center for Rheumatic Diseases, Japanese Red Cross Society, Kagoshima, Japan. hide@m2.kufm.kagoshima-u.ac.jp
authors.forename: Hideo
authors.initials: H
authors.lastname: Ohtsubo
authors.forename: Sanae
authors.initials: S
authors.lastname: Ohkura
authors.forename: Masaki
authors.initials: M
authors.lastname: Akimoto
authors.forename: Yoshiya
authors.initials: Y
authors.lastname: Arishima
authors.forename: Nobuhiko
authors.initials: N
authors.lastname: Sunahara
authors.forename: Tomomaro
authors.initials: T
authors.lastname: Izumihara
authors.forename: Nobutaka
authors.initials: N
authors.lastname: Eiraku
authors.forename: Tamami
authors.initials: T
authors.lastname: Yoshitama
authors.forename: Takemasa
authors.initials: T
authors.lastname: Matsuda
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D018501:Antirheumatic Agents / Q000097:blood / Q000627:therapeutic use*; D001172:Arthritis, Rheumatoid / Q000097:blood / Q000188:drug therapy*; D002097:C-Reactive Protein; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012263:Ribonucleosides / Q000097:blood / Q000627:therapeutic use*; D012720:Severity of Illness Index; D016896:Treatment Outcome
chemical_list: D018501:Antirheumatic Agents; D012263:Ribonucleosides; C010052:mizoribine; D002097:C-Reactive Protein