Lessons for rituximab therapy in patients with rheumatoid arthritis

B-cell depletion therapy is an effective option for the treatment of rheumatoid arthritis but often does not result in complete B-cell depletion. Complete B-cell depletion after rituximab treatment is associated with clinical response, and this outcome leads to long-term maintenance of therapy. Low pretreatment plasmablast counts, concomitant treatment with disease-modifying antirheumatic drugs, no smoking exposure, the presence of anticitrullinated protein antibodies or rheumatoid factor, and a low interferon signature are all predictive of complete B-cell depletion and clinical response. Half of patients who initially show complete B-cell depletion and clinical response after rituximab treatment eventually lose responsiveness with further infusions. However three-quarters of these patients regain this outcome in their following treatment cycle, suggesting that loss of response is reversible and that patients can still benefit from rituximab retreatment. The efficacy of reduced doses of rituximab is being investigated, but preliminary results suggest that these strategies are best used for maintenance therapy, particularly in patients who suffer adverse events or who are at a high risk of infection. Infusion-related reactions are the most common adverse events associated with rituximab treatment, and monitoring of IgG concentrations is crucial, as low concentrations are correlated with an increased risk of infection.