To evaluate the efficacy and safety of increasing the dose interval of subcutaneous tocilizumab (TCZ-SC) in patients with rheumatoid arthritis (RA) who are in clinical remission.
RA patients with active disease and an inadequate response to conventional synthetic disease-modifying antirheumatic drugs (csDMARDs) or to a biologic agent were entered into a single-arm treatment phase with 162 mg of TCZ-SC administered once weekly (TCZ-SC 162 mg qw) as monotherapy or in combination with a csDMARD for 24 weeks. Patients who achieved clinical remission at weeks 20 and 24 were randomized to continue with the same regimen or to switch to 162 mg TCZ-SC administered every 2 weeks (TCZ-SC 162 mg q2w) for 24 weeks (open-label). Patients with a Disease Activity Score in 28 joints (DAS28) of <2.6 were considered to be in clinical remission.
In total, 179 (45%) of 401 patients in the single-arm phase achieved clinical remission and were randomized to continue to receive TCZ-SC 162 mg qw (n = 89) or to switch to TCZ-SC 162 mg q2w (n = 90) for 24 weeks. At week 48, significantly more patients treated with TCZ-SC 162 mg qw remained in clinical remission compared to patients who received TCZ-SC 162 mg q2w (90% versus 73%; P = 0.004). The results of other efficacy measures revealed greater efficacy with TCZ-SC 162 mg qw, but none of the efficacy outcomes in this group were significantly different from those in patients treated with TCZ-SC 162 mg q2w, except for the mean change from baseline in the DAS28 score at week 48 (mean change -4.07 points [SD 1.29] versus -3.65 points [SD 1.35]; P = 0.034). Tolerability and safety parameters were similar between the treatment groups.
Increasing the dose interval of TCZ-SC in patients with RA was associated with a lower likelihood of maintaining remission after 24 weeks and was not associated with better tolerability. However, most patients were able to sustain remission with a half-dose of TCZ-SC, and therefore this strategy deserves further investigation.