Rituximab infusion-related adverse event rates are lower in patients with systemic lupus erythematosus than in those with rheumatoid arthritis.

Rituximab (RTX) is a therapeutic option for patients with SLE or RA. We conducted a prospective, longitudinal, observational study to compare rates of RTX-related adverse events (AEs) in these two patient groups. RTX was used in 23 patients with SLE that was refractory to conventional therapy and in 31 patients with RA that had been unsuccessfully treated with TNF-α inhibitors. Infusion-related and infectious AE rates were calculated for each group. Seven (22.5%) RA patients experienced an infusion-related reaction. These AEs involved 7/91 (7.7%) infusions administered in the RA group. None of the 102 infusions administered to SLE patients was associated with infusion-related AEs (P = 0.038 vs RA group). The mean daily glucocorticoid dose administered during the week preceding RTX treatment in the SLE group was higher than that for the RA group [0.25 (0.2) vs 0.18 (0.14) mg/kg, P = not significant] and significantly higher than that received by the subgroup of the seven RA patients who experienced infusion-related AEs [0.10 (0.02) mg/kg; P = 0.0017]. Infectious AE rates were also lower (but not significantly so) in the SLE group (8.7 vs 12.9% in RA). Repeated cycles of RTX in combination with different immunosuppressants is a safe therapeutic option for SLE and RA patients. The lower incidence of infusion-related AEs in the SLE patients might reflect the higher dosage glucocorticoid therapy they received during the week before RTX infusion.