Supplementary Material for: Mycophenolate as Maintenance Therapy for Lupus Nephritis with Impaired Renal Function

Background: Mycophenolate (MF) is effective as a maintenance therapy after induction therapy in patients with lupus nephritis (LN). However, little is known about its role in patients with impaired renal function. The purpose of this study was to evaluate the efficacy and safety of MF as a maintenance therapy for LN and its association with renal function. Methods: Data were obtained for 56 Spanish patients who were receiving MF as a maintenance therapy for LN. Patients were classified into two groups according to renal function at the initiation of MF treatment: group 1 [estimated glomerular filtration rate (eGFR) ≥60 ml/min/1.73 m²] and group 2 (eGFR <60 ml/min/1.73 m²). The primary endpoints of the study were the rates of renal relapse and responses, and their relationship with baseline renal function. Secondary outcomes were the appearance of side effects during treatment. Results: At initiation of MF treatment, the only differences between the groups were for age, hemoglobin levels, anti-DNA antibody titer, proteinuria, and renal function. In group 1 (n = 38), the eGFR was 98 ± 34 ml/min/1.73 m² and in group 2 (n = 18) the eGFR was 43 ± 14 ml/min/1.73 m². Only 3 cases had an eGFR <30 ml/min/1.73 m². No significant differences were observed in the rate of relapse at 6 months (group 1: 20%; group 2: 23%) or at 12 months (group 1: 25%; group 2: 17%). Response rates were also similar in both groups. Side effects were unremarkable. Conclusions: MF is effective and safe as a maintenance therapy for LN both in patients with normal renal function and in those with renal impairment.