Background Rheumatoid arthritis is a chronic autoimmune disease characterized by inflammation of the synovial tissue and destruction of the cartilage and bone. Antirheumatic treatment plays a important role in controlling the inflammation of rheumatoid arthritis and in minimizing joint damage. Rituximab has been successfully used to treat rheumatoid arthritis. It is a chimeric monoclonal antibody that targets the CD20 molecule expressed on the surface of B cells. Noteworhty, clinical and antidestructive effects often did not coincide.
Objectives To study the impact of B-cells depleting therapy (RTM) on joint destruction in correlation with clinical effects and B-cells counts.
Methods The study included 61 RA pts (average disease duration 10,1±7,7 y., mean DAS28 6,3±0,94, RF-positive 87%, ACCP–positive 93%) undergoing RTM therapy. Clinical effect was scored by EULAR criteria, radiographic progression was assessed using Sharp/van der Heijde (SvH) modified scoring method. B-cell level was measured with flow cytometry.
Results By Week 48 after 2 RTM courses good response was documented in 29,7% pts, good and satisfactory in 85,3%; remission was achieved in 14,6% pts. There was no radiographic progression in remission pts., in 83% of pts with low disease activity and in 33% - with moderate disease activity. Of note, further progression in joint space narrowing was more pronounced than bony tissue destruction - in 32% and 25%m respectively. Clinical and anti-destructive effects were often dis-matching: bone destruction was abrogated without any clinical improvement in 54% of pts. There was no significant difference in clinical effects of RTM dosing regimens (1000mg x2 or 500mg x2). More potent anti-destructive effect was documented in pts getting higher RTM dose values. No significant influence of B-cells depletion on radiographic progression of the disease was noticed. Although, in RA pts achieving remission B-cell depletion was more notable (Median, IQR 0% (0–1.133) as compared to pts with active disease (Median, IQR 0.8% (0.2–4.8, p 0.001).
Conclusions Clinical and anti-destructive effects of B-cell depletion therapy are not always equivalent. Therapeutic effect of two dosing regimens was similar, but the anti-destructive one was more pronounced with higher RTM doses. Radiographic progression did not show any correlation with the degree of B-cells depletion. Most pronounced B-cells depletion was documented in pts achieving remission.
Disclosure of Interest None declared