Efficacy and safety of S-flurbiprofen plaster in knee osteoarthritis patients: A 2-week randomized controlled Phase III clinical trial compared to diclofenac gel

Aim: S-flurbiprofen plaster (SFPP) is a novel topical nonsteroidal anti-inflammatory drug (NSAID) patch. This study aimed to assess the efficacy and safety of SFPP in knee osteoarthritis (OA) patients compared to diclofenac gel. Methods: This study was a multicenter, randomized, active-controlled, open-label, non-inferiority phase III trial. There were 311 enrolled patients treated by SFPP or diclofenac gel for 2 weeks. The primary efficacy outcome was the knee pain when rising from the specially arranged chair assessed by visual analog scale (rVAS). The other efficacy outcomes were clinical symptoms, pain on walking, global assessment by both investigator and patient, and use/non-use of the rescue drugs during the treatment period. Adverse events (AEs) were evaluated as the safety outcome. Results: The least-squares mean (95% CI) of ΔrVAS at the end of the study was 41.52 (39.16-43.88) mm in the SFPP group and 36.01 (33.69-38.33) mm in the diclofenac gel group, with a between-group difference of 5.51 (2.20-8.82), indicating non-inferiority. There were statistically significant differences between the groups in rVAS, clinical symptoms, pain on walking, and the global assessment by both investigator and patient. The incidence rate of AEs in the SFPP group was 5.8%, and there was no statistically significant difference from that in the diclofenac gel group (5.2%). Most of the AEs were mild, and no AE led to discontinuation. Conclusion: Non-inferiority of SFPP to diclofenac gel was demonstrated in the efficacy for pain on rising from a chair. SFPP was also well-tolerated in knee OA patients.