125 patients with chronic knee OA were randomized to receive either aceclofenac controlled release (CR) 200 mg oral tablets taken once-daily or aceclofenac immediate release (IR) 100 mg oral tablets taken twice-daily to assess non-inferiority of a lower dosing frequency to a higher one. Results at 4 week post-treatment revealed aceclofenac CR was non-inferior to aceclofenac IR in terms of change in mean VAS scores from baseline. Changes in VAS, KOOS subscale scores and ROM from baseline were all comparable between groups. Safety analysis revealed no differences between groups.