Low-dose solumatrix diclofenac in the treatment of osteoarthritis: A 1-year, open-label, phase III safety study

Introduction. Diclofenac is used for the treatment of osteoarthritis (OA); however, like other nonsteroidal anti-inflammatory drugs (NSAIDs) it can be associated with serious dose-related adverse events (AEs). Low-dose SoluMatrix_diclofenac has been developed to provide efficacy at lower diclofenac doses. A recently published Phase III study evaluated the efficacy and safety of SoluMatrix diclofenac 35 mg twice daily (b.i.d.) and thrice daily (t.i.d.) in patients with OA pain treated for 12 weeks. Methods. This Phase III multicenter, open-label study assessed the safety of SoluMatrix diclofenac in patients with OA dosed up to 52 weeks (ClinicalTrials.gov: NCT01510912). The study enrolled 602 chronic NSAID/acetaminophen users, aged ‡40 years with OA of the knee or hip. Patients received SoluMatrix diclofenac 35 mg b.i.d., which could be increased to t.i.d. and subsequently reduced to b.i.d. as needed. Safety assessments included AEs, vital signs, physical examination findings, 12-lead electrocardiogram, and clinical laboratory test results. Patient-reported outcomes were evaluated by the Short Form-36 (SF-36). Results. A total of 601 patients received SoluMatrix diclofenac; 373 of 601 patients (62.1%) received treatment for ‡11 months. The most frequent AEs included upper respiratory tract infection, headache, urinary tract infection, diarrhea, nasopharyngitis, and nausea. Serious gastrointestinal, cardiovascular, renal, and hepatic AEs were uncommon. A small proportion (99 patients, 16.5%) of patients discontinued participation in the study due to AEs. Clinically meaningful improvements from baseline in Physical Component Summary Scores of the SF-36 were noted at week 12 and were sustained through week 52. Improvements in six of the eight individual physical and mental SF-36 domains were also noted. Conclusion. SoluMatrix diclofenac treatment for up to 1 year was generally well tolerated in patients with OA pain and associated with improvement in quality of life measures. Trial Registration: www.clinicaltrials.gov identifier: NCT01510912.