Vol.22 No.6

Original Article

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

Authors

Hideo Ohtsubo1 , Sanae Ohkura1 , Masaki Akimoto1 , Yoshiya Arishima1 , Nobuhiko Sunahara1 , Tomomaro Izumihara2 , Nobutaka Eiraku3 , Tamami Yoshitama4 , Takemasa Matsuda1

  • Center for Rheumatic Diseases, Japanese Red Cross Society Kagoshima Hospital, 2545 Hirakawa, Kagoshima, 891-0133, Japan
  • Izumihara Rheumatoid Arthritis and Internal Medicine Clinic, Kagoshima, Japan
  • Eiraku Internal Medicine Clinic, Kagoshima, Japan
  • Yoshitama Rheumatoid Arthritis and Internal Medicine Clinic, Kagoshima, Japan
Received:

1 November 2011

Accepted:

1 February 2012

Published online:

6 March 2012

Full Text

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Abstract

Objectives 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 lg/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.

Key words

Disease Activity Score - Drug survival - Mizoribine - Rheumatoid arthritis - Single dose