Abstract
OBJECTIVE: To compare the effects of preventing radiographic progression (in its 3 components) of tocilizumab (TCZ) monotherapy with those of TCZ and methotrexate (MTX) in combination therapy (TCZ + MTX), and to evaluate possible effect modifiers in this model. METHODS: Randomized trials that compared TCZ monotherapy to TCZ + MTX combination therapy for differences in radiographic progression were analyzed on an individual patient data level using mixed-effects models, and data were collected from 820 subjects with either early rheumatoid arthritis (RA) or established RA. Outcomes were classified as the absence of radiographic progression after 2 years (i.e., preventing radiographic progression) as measured by total Sharp/van der Heijde score (SHS), erosion score, and joint space narrowing (JSN) score. Effect modification by baseline joint damage, disease duration, and Disease Activity Score in 28 joints (DAS28) was studied. RESULTS: Overall, TCZ + MTX combination therapy was more effective in preventing radiographic progression compared to TCZ monotherapy, which was measured by total SHS score. However, in patients with early RA who had more joint damage compared to those with less joint damage at baseline (relative risk [RR] 1.02 versus RR 0.91, respectively) or in patients with a lower DAS28 score compared to those with a higher DAS28 score (RR 1.04 versus RR 0.92, respectively) at baseline, this advantage disappeared. In patients with established RA, the advantage of TCZ + MTX versus TCZ alone in the prevention of radiographic progression disappeared with a longer disease duration at baseline (RR 1.04 versus 0.83). Results of erosion scores as an outcome were in line with these findings, though findings for JSN scores were less clear. CONCLUSION: Combination therapy with TCZ + MTX is more effective in preventing radiographic progression compared to TCZ monotherapy, but the effectiveness of TCZ monotherapy may approximate the effectiveness of TCZ + MTX in patients with early RA who have more joint damage and/or a lower DAS28 at baseline and in patients with established RA who have longer disease duration.