Efficacy and safety of eltenac gel in the treatment of knee osteoarthritis

Objective A double-blind, placebo-controlled dose-finding study was performed in 237 patients with predominantly unilateral knee osteoarthritis (OA) evaluating efficacy and safety of a new topical NSAID. Design The patients applied 3g tid eltenac gel 0.1%, 0.3%, 1% or placebo gel over a period of 4 weeks. The patients were supplied with paracetamol tablets as an escape analgesic. Primary efficacy end-point was mean global pain in the week preceding the examinations, evaluated on a visual analog scale (VAS). Secondary criteria were Lequesne's score ISK, Jezek score, muscle strength and dolorimeter measurements, walking time, clinical examination results of the knee joint and patient's and investigator's overall efficacy estimates. Results The graphical depiction of VAS and ISK suggested a dose-related efficacy, but the pre-planned statistical analysis did not show significant differences between treatments. In the patient subgroup with a higher degree of baseline severity of knee OA the ISK showed significant and relevant advantages of eltenac gel 1% to placebo at different examination times. Two patients each of the eltenac gel 1% group and the placebo group showed local intolerance reactions which subsided spontaneously. Conclusion This study did not provide confirmatory proof of an efficacy of topical eltenac in patients with knee OA. Methodological pitfalls and possible responder subgroups are described. Despite the difficulties, dose-finding studies seem to be feasible even with topical NSAIDs.