Maxime Verhoeven

87 TCZ vs. TCZ+MTX; prevention of radiographic progression in RA Figure 2 Relative chance of preventing radiographic progression in established RA.* Number of patients in low-level baseline joint damage subgroup; 96 in TCZ vs. 110 in TCZ+MTX, number of patients in high-level baseline joint damage subgroup; 105 in TCZ vs. 106 in TCZ+MTX. Number of patients in low-level baseline disease duration subgroup; 103 in TCZ vs. 105 in TCZ+MTX, number of patients in high-level baseline disease duration subgroup; 99 in TCZ vs. 110 in TCZ+MTX. Number of patients in low-level baseline DAS28 subgroup; 103 in TCZ vs. 104 in TCZ+MTX, number of patients in high-level baseline DAS28 subgroup; 99 in TCZ vs. 111 in TCZ+MTX. *Relative chances (95%CI) are based on stratified analyses, controlling for age, gender and DAS28 at baseline. A RR above 1 is associated with less radiographic progression for TCZ. Low/high levels of baseline joint damage (SvdH score ≤28.5/>28.5), disease duration (≤5.46 years/>5.46 years) or disease activity (DAS28 ≤6.37/>6.37) were based on their respective median values in the data. RA= rheumatoid arthritis; SvdH= Sharp van der Heijde; TCZ= tocilizumab; MTX= methotrexate; RR= relative chance; % Ref= proportion of patients with no progression (i.e., based on raw data) in the reference group, i.e., TCZ+MTX group. DISCUSSION In general, TCZ-monotherapy was found to have less effect on preventing radiographic progression than TCZ+MTX combination therapy, however, this effect was found to vary between patients depending on joint damage, disease duration and disease activity, all at baseline. When analyzing these modifying factors within the subgroups, we found the effectiveness of TCZ-monotherapy approximates that of TCZ+MTX for early RA patients with lower DAS28 (i.e., low-level subgroup) or (more) joint damage (i.e., high-level subgroup) at baseline. The ‘window of opportunity’ hypothesis 11 implies that RA is more susceptible for treatment during the first 6 months after disease onset. When symptoms are mild and slowly progressing (low disease activity), a considerable (unnoticed) delay 5