Efficacy and safety of tapentadol prolonged release formulation in the treatment of elderly patients with moderate-to-severe chronic osteoarthritis knee pain: a pooled analysis of two double-blind, randomized, placebo-, and active-controlled trials

Objective: To compare efficacy and safety of tapentadol prolonged release (PR) vs oxycodone controlled release (CR) in younger patients (<65 years of age) and in elderly patients (>= 65 and >= 75 years of age) in the treatment of moderate-to-severe chronic osteoarthritis (OA) knee pain. Methods: Data from two double-blind, randomized, placebo-, and oxycodone CR-controlled phase 3 trials were pooled and stratified by age. Primary efficacy end-points were change from baseline in average pain intensity at week 12 (US end-point) and over the entire maintenance period (non-US end-point). Results: A total of 1357 patients <65 years, 653 patients >= 65 years, and 176 patients >= 75 years of age were assessed. The comparison between tapentadol PR and oxycodone CR showed numerically better pain relief under tapentadol PR for both primary end-points in all three age groups. More favorable improvements were also observed for patient global impression of change, the Short Form-36 physical component score, and EuroQoL-5Dimensions health status index. In the elderly, incidences of dizziness and somnolence were comparable between active treatments, but incidences of nausea, vomiting, and constipation were considerably lower under tapentadol PR. Treatment completion rates were lowest under oxycodone CR; > 50% of elderly oxycodone CR patients named side-effects as the main reason for discontinuation. Conclusions: Tapentadol PR was effective in the treatment of moderate-to-severe chronic OA pain in elderly and younger patients. Compared to oxycodone CR, the overall and the gastrointestinal tolerability profile in particular were better in all tapentadol PR groups, regardless of age.