Biopsy-verified response of severe lupus nephritis to treatment with rituximab (anti-CD20 monoclonal antibody) plus cyclophosphamide after biopsy-documented failure to respond to cyclophosphamide alone.

BACKGROUND: The monoclonal anti-B cell antibody rituximab (Rituxin, Mabthera) may be of benefit in antibody-driven diseases, including systemic lupus erythematosus (SLE) nephritis.

PATIENTS AND TREATMENT: Two female patients with biopsy-confirmed severe and active SLE nephritis despite treatment with cyclophosphamide (CyX) were given four rituximab infusions plus two additional CyX infusions.

RESULTS: Both patients tolerated the treatment well and SLE activity improved. On repeat kidney biopsy after the combined treatment, Patient 1 showed a profound reduction of nephritis activity, and she was maintained on low-dose prednisolone only. A repeat biopsy after 1 year confirmed the sustained reduction of lupus nephritis activity. In Patient 2, rebiopsy after combined treatment also showed a significant reduction in disease activity.

CONCLUSION: These cases provide histopathological documentation of a significant treatment benefit from rituximab plus CyX in two patients refractory to CyX alone. This combination is being explored further as salvage therapy for such CyX-resistant patients.