Objective To compare the efficacy of tacrolimus (TAC) and mycophenolate mofetil (MMF) for the initial therapy of lupus nephritis (LN).

Study design This is an open randomised controlled parallel group study.

Methods Adult patients with biopsy-confirmed active LN (class III/IV/V) were randomised to receive prednisolone (0.6 mg/kg/day for 6 weeks and tapered) in combination with either TAC (0.06–0.1 mg/kg/day) or MMF (2–3 g/day) for 6 months. Good responders were shifted to azathioprine for maintenance. The primary outcome was the rate of complete renal response (CR) at 6 months and the secondary outcomes included partial renal response, renal flares and decline of renal function over time.

Results 150 patients (92% women; aged 35.5±12.8 years; 81% class III/IV) were randomised (76 MMF, 74 TAC). At month 6, the rate of CR was 59% in the MMF and 62% in the TAC group (treatment difference: 3.0% (−12%, 18%); p=0.71). Major infective episodes occurred in 9.2% patients treated with MMF and in 5.4% patients treated with TAC (p=0.53). Maintenance therapy with azathioprine was given to 79% patients. After 60.8±26 months, proteinuric and nephritic renal flares developed in 24% and 18% of patients in the MMF group and 35% (p=0.12) and 27% (p=0.21) in the TAC group, respectively. The cumulative incidence of a composite outcome of decline of creatinine clearance by ≥30%, development of chronic kidney disease stage 4/5 or death was 21% in the MMF and 22% in the TAC group of patients (p=0.35).

Conclusions TAC is non-inferior to MMF, when combined with prednisolone, for induction therapy of active LN. With azathioprine maintenance for 5 years, a non-significant trend of higher incidence of renal flares and renal function decline is observed with the TAC regimen.

Trial registration number Hospital Authority Research Ethics Committee Clinical Trial Registry (HARECCTR0500018; Hong Kong) and US ClinicalTrials.gov (NCT00371319).