To determine the safety and efficacy of rituximab treatment in patients with active seropositive rheumatoid arthritis (RA) who had experienced an inadequate response to treatment with anti-tumor necrosis factor-alpha agents and/or traditional disease modifying antirheumatic drugs.
Rituximab was administered to 17 patients as weekly infusions for 4 consecutive weeks. Patients continued their baseline therapy and were followed for 28 weeks.
All patients were evaluable for safety, and 13 for efficacy. Profound B cell depletion occurred by 12 weeks and was sustained at 24 weeks, whereas T cell, complement, and immunoglobulin levels remained within normal ranges. Rituximab was well tolerated, with no infusion related reactions and only mild/moderate adverse events. American College of Rheumatology 20% response (ACR20) was achieved in 55% of patients by Week 5, 75% by Week 8, 50% at Week 16, and 67% at Week 28. Corresponding ACR50 and ACR70 responses were achieved in 36% and 18%, 25% and 17%, 42% and 25%, and 33% and 17% of patients at Weeks 5, 8, 16, and 28, respectively. There were significant improvements over baseline in tender and swollen joint counts (p < 0.0001), physician's global assessment of disease activity (p = 0.0001), and patient assessed pain (p = 0.0005) and disability (p = 0.0386). Erythrocyte sedimentation rate (p = 0.0361) and rheumatoid factor titers (p < 0.0001) also decreased significantly.
These results support the hypothesis that B cells play an important role in RA pathophysiology, and suggest that rituximab is effective and well tolerated, with a rapid onset of clinical benefit, in patients with refractory, seropositive active RA.