Efficacy of two cyclophosphamide regimens for the treatment of lupus nephritis in Puerto Ricans: low vs. standard dose.

INTRODUCTION The clinical outcome and therapeutic response to immunosuppressive agents vary among patients with lupus nephritis of different ethnic populations. Thus, we evaluated the efficacy of two established treatment protocols for lupus nephritis (low-dose versus standard-dose cyclophosphamide) in Puerto Ricans with systemic lupus erythematosus (SLE). METHODS A retrospective cohort of 49 adult patients with SLE treated with intravenous low or standard-dose cyclophosphamide for clinical or biopsy confirmed lupus nephritis was studied. Demographic parameters, clinical manifestations, autoantibodies and pharmacological treatments were determined prior to cyclophosphamide treatment. Renal parameters, disease activity, damage accrual and corticosteroid use were determined before and after treatment. Cyclophosphamide-associated adverse events were also examined. Univariable and bivariable analyses were used to evaluate group differences. RESULTS Thirty-nine SLE patients received the standard-dose treatment and ten patients the low-dose therapy. Prior to cyclophosphamide infusion, demographic parameters, clinical manifestations, autoantibodies profile, disease damage and pharmacologic treatments were similar in both groups. Disease activity was higher in the low-dose group. After cyclophosphamide therapy, significant improvement of renal parameters (increase in the glomerular filtration rate and decrease in hematuria, pyuria, urinary cellular casts, proteinuria and hypertension) were observed only for patients that received the standard-dose therapy. Disease activity and corticosteroids requirement decreased in both groups after treatment. No differences were observed for adverse events associated with cyclophosphamide. CONCLUSIONS The standard-dose cyclophosphamide therapy appears to be more effective, and similar in terms of drug safety, than the low-dose regime for lupus nephritis in Puerto Ricans with SLE.