Rituximab therapy in lupus nephritis: current clinical evidence.

The complexity of the therapeutic approach in lupus nephritis (LN) is increased by the large number of patients who do not respond to first-line therapies and by relapses after initial clinical remission. The emergence of biological agents has increased the therapeutic armamentarium available in these complex situations, but their use is limited by the lack of licensing. We analysed current evidence on the therapeutic use of rituximab in adult LN patients by systematic analysis of seven observational studies published since 2005 (four in 2009), which included 106 LN patients treated with rituximab. A complete or partial therapeutic response was achieved in 73 (69%) patients. The response according to the type of LN was stated in 79 cases: 8 (80%) patients with type III LN had a favourable, 26 (67%) of those with type IV, 4 (57%) of those with type V and 18 (78%) of those with mixed membranous-proliferative LN. The main factors associated with no response were younger age, black race and lack of CD19(+) cell depletion. The lowest rates of complete response were observed in patients with type V LN, especially those with associated proliferative lesions. Although it is not yet possible to make definite recommendations, the global analysis of these cases supports the off-label use of rituximab in severe, refractory LN cases.