To evaluate the efficacy and safety of human anti-interleukin-6 (IL-6) receptor antibody (tocilizumab) in combination with disease-modifying anti-rheumatoid drugs (DMARDs) for the treatment of rheumatoid arthritis (RA) patients with moderate to severe activity and inadequate response to DMARDs.
The present study was a multi-center, randomized, double-blinded, placebo controlled trial. Eligible patients were randomized (tocilizumab:Placebo = 2:1) to one of two groups: tocilizumab 8 mg/kg group or placebo group. The drug was administered every 4 weeks by infusion along with stable dose of DMARDs. The primary analysis evaluated at week 24 included: the proportion of patients with American College of Rheumatology (ACR)20, ACR50 and ACR70 response; the average changes of ACR core components from baseline; the proportion of patients with disease activity score (DAS28) ≤ 3.2 and DAS28 < 2.6. Patients who completed double-blinded phase could choose to enter 24-week open-label therapy with tocilizumab 8 mg/kg infusion every 4 weeks.
Totally 139 patients from tocilizumab group and 69 patients from placebo group completed the 24-week double-blinded period respectively with comparable baseline characteristics. The proportion of patients with ACR20, ACR50 and ACR70 in tocilizumab group was significantly higher than that in placebo group: 69.8% vs 24.6% (P < 0.05), 38.8% vs 10.1% (P < 0.05) and 12.9% vs 2.9% (P < 0.05) respectively. ACR core components change, proportion of patients with DAS28 ≤ 3.2 and DAS28 < 2.6 were all better in tocilizumab group than those in the placebo group. Decreased level of biomarkers C-terminal crosslinking telopeptide of type I collagen generated by matrix metalloproteinases (ICTP), matrix metalloproteinase 3 (MMP-3) and N-terminal propeptide of type IIA collagen (PIIANP) were observed in patients with tocilizumab treatment, indicating its positive effects on bone metabolism. A total of 202 patients received tocilizumab treatment in the study with the longest duration as 48 weeks, and all the indexes were improved further with the elongation of the treatment time. During the doubled blind phase, 42.4% of patients in the tocilizumab group had ≥ 1 adverse event (AE), compared with 27.9% of patients in the control group. The most common AE was infection, and most of the AEs were mild to moderate. Serious AEs occurred in 0.7% and 5.9% of patients in the tocilizumab and control groups, respectively. More patients in the tocilizumab group had higher percentage of increased alanine transaminase and aspartate transaminase (12.9% and 9.4%) compared to the placebo group (4.4% and 4.4%). Increase of total cholesterol, high density lipoprotein, low density lipoprotein, and triacylglycerol were observed in the tocilizumab group, but no increase of occurrence of cardiac events. No additional safety signals were found during the extension phase.
The study showed that tocilizumab combined with DMARDs was safe and effective in reducing articular and systemic symptoms in patients with an inadequate response to DMARDs.