Efficacy of rituximab in 164 patients with biopsy-proven lupus nephritis: pooled data from European cohorts.

OBJECTIVE: To present a pooled analysis of the efficacy of rituximab from European cohorts diagnosed with biopsy-proven lupus nephropathy (LN) who were treated with rituximab. METHODS: Consecutive patients with biopsy-proven LN treated with rituximab in European reference centers were included. Complete response (CR) was defined as normal serum creatinine with inactive urinary sediment and 24-hour urinary albumin <0.5 g, and partial response (PR) as a >50% improvement in all renal parameters that were abnormal at baseline, with no deterioration in any parameter. RESULTS: 164 patients were included (145 women and 19 men, with a mean age of 32.3 years). Rituximab was administered in combination with corticosteroids (162 patients, 99%) and immunosuppressive agents in 124 (76%) patients (cyclophosphamide in 58 and mycophenolate in 55). At 6- and 12-months, respectively, response rates were 27% and 30% for CR, 40% and 37% for PR and 33% for no response. Significant improvement in 24-h proteinuria (4.41 g. baseline vs 1.31 g. post-therapy, p=0.006), serum albumin (28.55 g. baseline to 36.46 g. post-therapy, p<0.001) and protein/creatinine ratio (from 421.94 g/mmol baseline to 234.98 post-therapy, p<0.001) at 12 months was observed. A better response (CR+PR) was found in patients with type III LN in comparison with those with type IV and type V (p=0.007 and 0.03, respectively). Nephrotic syndrome and renal failure at the time of rituximab administration predicted a worse response (no achievement of CR at 12 months) (p<0.001 and p=0.024, respectively). CONCLUSION: Rituximab is currently being used to treat refractory systemic autoimmune diseases. Rituximab may be an effective option for patients with lupus nephritis, especially those refractory to standard treatment or who experience a new flare after intensive immunosuppressive treatment.