Mizoribine therapy for patients with lupus nephritis: the association between peak mizoribine concentration and clinical efficacy

Abstract

The clinical efficacy of mizoribine (MZR; 4-carbamoyl-1-b-d-ribofuranosylimidazolium) in patients with lupus nephritis was investigated. Thirteen Japanese patients with biopsy-proved lupus nephritis were enrolled in this study. A change in global assessments score, total protein (TP) of serum, serum creatinine, creatinine clearance (Ccr), proteinuria, titers of serum anti-ds DNA antibody, C3, C4, and hemolytic complement activity (CH50) were examined. Following MZR treatment, the level of urinary protein decreased (P < 0.05), whereas the level of Ccr increased (P < 0.05). Moreover, the level of TP significantly increased from 5.5?g/dl to 6.3?g/dl (P < 0.01) and the level of C3 increased significantly (P < 0.01). However, there was no change in the levels of both C4 and CH50. The titer of anti-ds DNA antibody significantly decreased (P < 0.05). The dosage of prednisolone could be tapered from 24.8?mg to 14.9?mg daily during the period. The clinical effects associated with MZR concentration in the blood revealed that there was a significant correlation between the peak MZR blood concentration of more than 0.66?µg/ml and clinical improvement (P = 0.021). Our results suggest that an optimal MZR blood concentration was important for the treatment of lupus nephritis.