Lower-dose diclofenac submicron particle capsules provide early and sustained acute patient pain relief in a phase 3 study.

Background: Non-steroidal anti-inflammatory drugs are prescribed for the treatment of patients with acute pain but use of such analgesics is associated with dose-dependent adverse events (AEs). Diclofenac submicron particle capsules have been developed using SoluMatrix technology to provide analgesia at lower doses than available solid oral dosing forms. Our study evaluated the analgesic efficacy and safety of lower-dose diclofenac submicron particle capsules in patients with acute pain following elective surgery.

Methods: A phase 3, multicenter, double-blind study enrolled 428 patients, aged 18 to 65 years, with moderate-to-severe pain following bunionectomy under regional anesthesia. Patients experiencing a pain intensity rating of ≥ 40 mm on a 100-mm Visual Analog Scale were randomized to receive lower-dose diclofenac submicron particle capsules (35 or 18 mg, 3 times daily [TID]), celecoxib (200 mg, twice daily [BID], 400-mg loading dose), or placebo. The primary efficacy parameter was the overall (summed) pain intensity difference measured over 0 to 48 hours (SPID-48). Secondary efficacy parameters included pain intensity difference (PID) at scheduled assessments.

Results: Lower-dose diclofenac submicron particle capsules 35 mg TID (524.05; P < 0.001), 18 mg TID (393.25; P = 0.010), and celecoxib 200 mg BID (390.22; P = 0.011) demonstrated significant pain control compared with placebo (77.10) for the primary efficacy parameter, mean SPID-48. Diclofenac submicron particle capsules 35 mg TID (4.52) provided some pain control (higher mean PID) at 30 minutes following administration, in contrast to celecoxib 200 mg BID (0.80), diclofenac submicron particle capsules 18 mg TID (0.31), and placebo (0.12). Better pain control (PID) was noted across all active treatment groups at 5 hours compared with placebo (P ≤ 0.03), and pain relief was sustained throughout the treatment period. The most frequent non-procedure-related AEs were nausea, headache, dizziness, and vomiting.

Conclusion: Lower-dose diclofenac submicron particle capsules provided effective analgesia in this phase 3 clinical study in patients with acute pain and are a potentially promising option for the treatment of patients with acute pain.