Rituximab in psoriatic arthritis: an exploratory evaluation

Current therapies for psoriatic arthritis (PsA) comprise synthetic drugs and tumour necrosis factor inhibitors. In contrast, other biologicals including rituximab (RTX) are available for treating rheumatoid arthritis (RA). RTX is effective in autoantibody positive RA patients, although some efficacy has been reported in seronegative individuals. RTX has not yet been assessed in PsA. Therefore, an open label study of RTX in PsA was performed.

Nine patients with PsA and 14 with RA received RTX at 1000 mg twice within 14 days and were evaluated over 6 months.

A PsA response criteria response was attained in 56% of patients. DAS28 improved from 6.2 to 4.9 (medians) in PsA and 6.4 to 5.2 in RA, and Health Assessment Questionnaire from 1.5 to 1.0 and from 2.1 to 1.4, respectively (all p≤0.05). Disease Activity index for PSoriatic Arthritis changed from 52.0 to 32.5 (p<0.05); C reactive protein and Psoriasis Area and Severity Index did not change significantly. RTX was tolerated well.

In this exploratory open study, RTX exhibited significant efficacy in PsA patients with long-standing disease. Thus, RTX may have efficacy in PsA warranting a randomised controlled clinical trial.