Several intra-articular hyaluronic acid products are available for treating osteoarthritis (OA) of the knee, including hylan G-F 20 and the bioengineered straight-chain hyaluronic acid (Bio-HA). A recently published study in patients with knee OA demonstrated non-inferiority with regard to efficacy, using the pain subscore of the Western Ontario and McMaster Universities Osteoarthritis Index (safety data favoured Bio-HA with regard to knee effusions). However, the Osteoarthritis Research Society International (OARSI) Standing Committee for Clinical Trials Response Criteria Initiative together with the Outcome Measures in Rheumatology (OMERACT) committee have published new response criteria for OA clinical trials. These criteria focus on change in pain and physical function. The aim of this study was to reanalyse the data from the original comparative study of hylan G-F 20 and Bio-HA in knee OA utilising the new OMERACT-OARSI response criteria.
The original study was a prospective, multicentre, randomized, double-blind trial of 321 patients with knee OA who received hylan G-F 20 or Bio-HA via three intra-articular injections 1 week apart. This post-hoc analysis of the data using the modified OMERACT-OARSI responder criteria focused only on efficacy.
Using the OMERACT-OARSI criteria, 112 of the 157 patients (71%) receiving Bio-HA were considered to have a response compared with 99 of the 158 patients (63%) receiving hylan G-F 20 (p = 0.10).
Application of the new, standardized definition of a responder in OA clinical trials to the existing data reinforces that Bio-HA is non-inferior to hylan G-F 20 for knee OA. Both agents were similarly well tolerated, but Bio-HA was associated with a lower incidence of effusions, suggesting that Bio-HA has an improved risk-benefit profile compared with hylan G-F 20.