Conditions: Pain Knee Osteoarthritis
Keywords: Osteoarthritis Knee Pain Assessment CG5503 PR Centrally acting analgesic Placebo Oxycodone Chronic Pain due to knee Osteoarthritis Tapentadol
Allocation: RANDOMIZED | Intervention model: PARALLEL
Enrollment: 990
Healthy volunteers: no

Brief summary:
The purpose of this study is to evaluate whether tapentadol (CG5503) prolonged-release (PR) tablets at doses of 100-250 mg twice daily provide a better pain relief in patients with moderate to severe chronic pain due to osteoarthritis of the knee than a placebo (a medication without active substance). In addition the tolerability of CG5503 PR will be assessed. One third of the patients will receive CG5503 and one third will receive placebo. For further comparison one third of the patients will receive oxycodone controlled release (CR) at doses of 20-50 mg twice daily which is an active approved pain medication. Please note that tapentadol ER (Extended Release) and tapentadol PR (Prolonged Release) are identical and used interchangeably. This is due to United States of America and European naming conventions.

Detailed description:
This is a randomized (study medication assigned to patients by chance), double-blind (neither patient nor investigator knows which patient gets which study medication, i.e. CG5503, placebo, oxycodone), placebo and active control study. The primary objective is to evaluate the efficacy and safety of orally administered tapentadol (CG5503) prolonged-release (PR) at doses of 100-250 mg (base) twice daily in patients with moderate to severe chronic pain from osteoarthritis (OA) of the knee. The study will consist of five periods: screening (to assess eligibility), washout (3-7 days with determination of a baseline pain intensity), titration (of dose over 3 weeks to the optimal individual level), maintenance (investigational drug intake for 12 weeks with adjustments allowed), and follow-up (2 weeks after end of treatment). The study hypothesis is that the study drug will be more effective than placebo in reducing patients' pain intensity. The secondary objectives include the collection of pharmacokinetic (related to how the body absorbs, distributes, changes and excretes the drug) information for dose verification. The efficacy objectives will be assessed by comparing the baseline pain level to the pain level during the maintenance period. This will be done by looking at the patients' pain diary information (electronic diaries).

Arms:
arm 1: The starting dose of placebo was matched with the active treatment arms taken twice daily for the first 3 days. The dose was then increased to match the active treatments for at least 4 days. Thereafter, during the titration and maintenance phase participants were allowed to increase the dose every 3 days as in the active treatment arms. Dose decreases were allowed without time restrictions. arm 2: The starting dose was tapentadol ER 50 mg twice daily for 3 days. The dose was then increased to 100 mg tapentadol ER twice daily for at least 4 days. Thereafter, during the titration and maintenance phase participants were allowed to increase the dose every 3 days. Dose decreases were allowed without time restrictions. arm 3: The starting dose was oxycodone CR 10 mg twice daily for 3 days. The dose was then increased to 20 mg oxycodone CR twice daily for at least 4 days. Thereafter, during the titration and maintenance phase participants were allowed to increase the dose every 3 days. Dose decreases were allowed without time restrictions.

Interventions: intervention 1: Tapentadol ER (100 to 250 mg twice daily) intervention 2: Matching Placebo (twice daily) intervention 3: Oxycodone CR (20 to 50 mg twice daily)
Intervention descriptions: intervention 1: 50, 100, 150, 200, 250 mg twice a day (BID) during 15 weeks (3 weeks titration and 12 weeks maintenance) intervention 2: Matching Placebo during 15 weeks (3 weeks titration and 12 weeks maintenance) intervention 3: 10, 20, 30, 40, 50 mg twice a day (BID) during 15 weeks (3 weeks titration and 12 weeks maintenance)

Protocol document: