VIENNA — Rituximab successfully induced remission of severe extrarenal systemic lupus erythematosus previously unresponsive to cyclophosphamide and/or mycophenolate in five of six treated patients in a small series, Constantine K. Saadeh, M.D., reported at the annual European congress of rheumatology.
Previous studies of rituximab in SLE have focused on the agent's utility in patients with refractory lupus nephritis. But in Dr. Saadeh's six-patient series, the anti-CD20 chimeric monoclonal antibody targeting mature B cells induced remission in patients with lupus skin, lung, and synovial disease.
All five responders to two 500-mg doses of rituximab given a week apart experienced disease remissions lasting at least 3 months. All five experienced a transient 2- to 3-week drop in their globulin fraction beginning roughly a week after treatment.
The sole rituximab nonresponder had mixed lupus nephritis and chronic glomerulonephritis that continued to deteriorate, requiring hemodialysis, added Dr. Saadeh, an Amarillo, Tex., rheumatologist.
The rituximab nonresponder was also the only one of the six patients who did not have depressed complement levels at baseline. It's possible that this agent requires depressed complement levels in order to be effective in SLE, although that hypothesis will require further investigation, the physician noted at the meeting, which was sponsored by the European League Against Rheumatism.