Off-Label Rituximab for Lupus in Europe: Used Seldom, But Widely

While rituximab (RTX) is not yet approved in Europe for use in systemic lupus erythematosus (SLE) it is being used off-label in many countries, mostly among SLE patients of a somewhat higher age with later stage, more severe disease, according to data presented at the 2013 annual meeting of the European League Against Rheumatism (EULAR) in Madrid.

Data from the International Registry for Biologics in SLE (IRBIS), encompassing 28 centers in 11 European countries, reveals that almost 60% of the SLE patients started on RTX off-label have lupus nephritis.

The overall use of rituximab was estimated at 0.5-1.3% of all SLE patients, mostly in those with more severe and refractory disease, "which is of course also in keeping with the fact that this is an off-label therapy," says Ronald van Vollenhoven MD PhD, a professor in the Unit for Clinical Therapy Research in Inflammatory Diseases at the Karolinska University Hospital in Sweden, who led the study. The researchers analyzed data for 175 SLE patients, 90% of them female Caucasians, and found that 103 (mean age 41) were treated off-label with RTX, mainly to control high disease activity.

Steroid sparing was the main reason for initiating conventional, non-biologic immunosuppressives (ISs), mostly mycophenolate mofetil (43%) or azathioprine (33%), among the 72 SLE patients in the study who did not take rituximab (mean age 36),

Significant differences in mean disease duration were seen in the RTX-treated patients (9.1 years compared to 4.1 for those started on ISs), as well as in SLEDAI scores (12.2 versus 9.4) and SLICC damage index (1.6 compared to 0.57).

There were slight differences in the number of women with lupus nephritis, (58% of those treated with RTX compared with 53% percent for ISs), but no significant differences in the distribution of other organ manifestations such as hematological lupus, musculoskeletal lupus, skin disease or CNS lupus.