Efficacy evaluation of highly purified intra-articular hyaluronic acid (Sinovial(®)) vs hylan G-F20 (Synvisc(®)) in the treatment of symptomatic knee osteoarthritis. A double-blind, controlled, randomized, parallel-group non-inferiority study.

OBJECTIVE: Knee osteoarthritis is a major cause of disability and pain. This phase III, double-blind (patient and observer blinded,) multicenter, randomized, non-inferiority study was conducted to demonstrate the non-inferiority of the highly purified intra-articular injection of hyaluronic acid (Sinovial(®)) in comparison to Hylan G-F20 (Synvisc(®)) in the treatment of knee osteoarthritis.

METHODS: A total of 381 patients were randomly assigned to receive either the test drug, 16 mg/2 ml (0.8%) highly purified ia hyaluronic acid of biofermentative origin (Sinovial(®)), or the comparative drug, 16 mg/2 ml of 0.8% hylan G-F20 (Synvisc(®)). The duration of the treatment was 2 weeks (three injections at 1-week interval), followed by an observation period of 6 months. The primary efficacy variable was the improvement in mean Western Ontario and McMaster Universities (WOMAC) pain subscore from baseline to the final visit (week 26), compared between the two treatment groups. The acceptable margin for non-inferiority was chosen to be 8 mm.

RESULTS: At week 26, WOMAC pain subscores decreased by a mean of 32.5 for both Sinovial(®) and Synvisc(®). These results met prespecified criteria for non-inferiority for both the Intent-to-Treat and Per-Protocol populations. There were no statistically significant differences between groups at 26 weeks, although Sinovial(®)-treated patients tended to have a slightly better outcome for select variables, as they did at earlier time-points, some of which reached statistical significance. Both hyaluronic acid preparations were well-tolerated, with no statistically significant differences in tolerability profile between groups.

CONCLUSION: Sinovial(®) and Synvisc(®) treatments were found to be equivalent, both in terms of efficacy and safety.

CLINICAL TRIAL NUMBER: NCT00556608 (ClinicalTrials.gov Identifier).