To investigate the efficacy and safety of a cream containing 5% ibuprofen (Dolgit) cream) in primary knee osteoarthritis (OA) in a double-blind, randomized, placebo-controlled, parallel-group study using an adaptive sequential design.
Patients of both sexes aged 40-75 years, with a visual analog scale (VAS) score for pain on motion of >or= 40 mm, a Lequesne index score of 5-13, and a Kellgren-Lawrence radiographic score grade II-III were enrolled between January 2001 and July 2001. Study medication was applied in a 10-cm strip tid for 7 days on the more painful knee. Each strip of the active treatment contained approximately 200 mg ibuprofen. The primary efficacy variable was the treatment response rate compared between the 2 groups. Response was defined as a reduction of pain on motion, self-assessed on VAS, of >or= 18 mm or >or= 23% compared to baseline.
The second interim analysis scheduled post-inclusion of 2 25 patients revealed a response rate of 21 patients (84.0%) in the ibuprofen group and of 10 patients (40.0%) in the placebo group (p = 0.0015). The study was then terminated. All secondary endpoints such as pain at rest, overall pain, Lequesne index, and global assessment of efficacy also showed the superiority of ibuprofen. No adverse event was recorded.
The efficacy and safety of ibuprofen cream in treatment of primary knee OA were statistically significant and clinically relevant compared to placebo.