Efficacy and safety of a single intra-articular injection of 6 ml Hylan G-F 20 compared to placebo in Chinese patients with symptomatic knee osteoarthritis: C-SOUND study, a 26-week multicenter double-blind randomized placebo-controlled trial in China

BACKGROUND: Single 6 ml Hylan G-F 20 injection, is indicated for knee osteoarthritis patients who have failed to respond to non-pharmacologic therapy and/or simple analgesics. To obtain more thorough understanding of the clinical efficacy and safety, a randomized clinical trial was conducted comparing intra-articular (IA) administration of single 6 ml Hylan G-F 20 injection versus placebo in knee OA patients of Chinese ethnicity. METHODS: This was a randomized, multi-center, double-blind, placebo-controlled clinical trial conducted in 21 centers across China. Four hundred forty adults with knee OA received a single 6 ml Hylan G-F 20 or placebo injection and were evaluated for clinical efficacy and safety outcomes over 26 weeks. Western Ontario and McMaster Universities OA (WOMAC) A1 index, treatment-emergent adverse events (TEAEs) and standard safety parameters were measured at pre-injection, and at weeks 1, 4, 8, 12, 16, 20 and 26 post-injection. RESULTS: Four hundred forty patients (male: 98 [22.3%]; female: 342 [77.7%]) were randomized. The mean age [standard deviation (SD)] was 61.5 (7.9) years. All patients were of East Asian ethnicity. Mean WOMAC A1 score at baseline was 5.3 (1.2) and 5.2 (1.3) in single 6 ml Hylan G-F 20 injection and placebo groups, respectively. Significant reductions of WOMAC A1 score were observed in both treatment groups when compared to baseline at 26 weeks post-injection, with the mean reduction of [standard error (SE)/percentage] -2.146 (0.108)/− 40.5% and − 2.271 (0.110) /− 43.7% in the single 6 ml Hylan G-F 20 injection and the placebo groups, respectively. Additionally, clinically important reductions in pain at 26 weeks was reported in 67.0 and 68.2% in single 6 ml Hylan G-F 20 injection and placebo groups (p = 0.36). Regarding safety, TEAEs were similar between the two treatment groups (hylan G-F 20 single: 61.5%; placebo: 64.5%). CONCLUSIONS: While the magnitude of the effect of a single 6 ml Hylan G-F 20 injection in this study is consistent with previously published literature with respect to the efficacy and safety of the drug, the current study shows a strong IA placebo effect and did not established superiority of single 6 ml Hylan G-F 20 injection over IA placebo in Chinese knee OA patients. TRIAL REGISTRATION: Prospectively registered Jun 16, 2017 at www.clinicaltrials.gov (NCT03190369). SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12891-021-04252-2.