Objective: To evaluate long term efficacy of three iterative courses of three weekly intra-articular (IA) injections of NRD101 in the treatment of symptomatic knee osteoarthritis (OA).
Patients and methods: A 1 year prospective, multicentre, randomised, double blind, placebo controlled study of 301 patients aged >50 years with painful and radiological medial knee OA. Patients were randomly assigned into three groups receiving: (1) three courses of three IA injections of hyaluronic acid (HA) + oral placebo; (2) IA injections of saline solution + diacerein 100 mg/day; (3) IA injections of saline solution + oral placebo. Demographic data and symptomatic criteria—pain, Lequesne's index, patient's global assessment of disease activity, percentage of painful days—were obtained during the study; primary structural criterion was JSW. Efficacy criteria were changes in pain VAS, joint space narrowing (JSN), and percentage of progressors (JSN >0.5 mm). An intention to treat analysis was used for symptomatic variables, and completer analysis for structural variables.
Results: Baseline characteristics were similar between the three groups. Mean (SD) improvement in pain VAS was clinically relevant (–33.9 (27.3), n = 301), but with no difference between the groups (p = 0.96). JSW deteriorated (–0.09 (0.55) mm, n = 277, p = 0.01), but with no difference between the groups (p = 0.82). Percentages of progressors were 17.7, 18.9, and 20.3% (p = 0.90), in groups 1, 2, and 3, respectively.
Conclusion: A weak but statistically significant structural deterioration occurred over 1 year, together with clinically relevant symptomatic improvement in patients receiving oral drug and iterative IA injections. Symptomatic and/or structural effects for both this new HA compound and diacerein were not demonstrated.