A double-blind, double-dummy, randomized controlled, multicenter trial of 99Tc-methylene diphosphonate in patients with moderate to severe rheumatoid arthritis.

Background Clinical observational studies revealed that 99Tc-methylene diphosphonate (99Tc-MDP) could reduce joint pain and swollenness in rheumatoid arthritis (RA) patients. This multicenter, randomized, double-blind, double-dummy study aimed to evaluate the effects of 99Tc-MDP plus methotrexate (MTX) vs. MTX alone or 99Tc-MDP alone on disease activity and structural damage in MTX-naive Chinese patients with moderate to severe RA. Methods Eligible patients with moderate to severely active RA were randomized to receive 99Tc-MDP plus MTX (n = 59) vs. MTX (n = 59) alone or 99Tc-MDP (n = 59) alone for 48 weeks from six study sites across four provinces in China. The primary outcomes were the American College of Rheumatology 20% improvement (ACR20) response rates at week 24 and changes in modified total Sharp score at week 48. Results At week 24, the proportion of participants achieving ACR20 was significantly higher in the MTX + 99Tc-MDP combination group (69.5%) than that in the MTX group (50.8%) or 99Tc-MDP group (47.5%) (P = 0.03 for MTX + 99Tc-MDP vs. MTX, and MTX + 99Tc-MDP vs.99Tc-MDP, respectively). The participants in the MTX + 99Tc-MDP group and the 99Tc-MDP group had significantly less important radiographic progression than the participants in the MTX group over the 48 weeks (MTX + 99Tc-MDP vs. MTX: P = 0.03, 99Tc-MDP vs. MTX: P = 0.03, respectively). There was no significant difference in terms of adverse events (AEs) among the groups. No serious AEs were observed. Conclusions This study demonstrated that the combination of 99Tc-MDP with MTX inhibited structural damage and improved disease activity in RA patients compared with MTX and 99Tc-MDP monotherapies, without increasing the rate of AEs. Additional clinical studies of 99Tc-MDP therapy in patients with RA are warranted. Trial registration Chictr.org, ChiCTR-IPR-14005684; http://www.chictr.org.cn/showproj.aspx?proj=10088.