By Jill Stein
CHICAGO -- April 16, 2008 -- Tapentadol extended release at a daily dose of 200 mg is effective for up to 4 weeks in patients with moderate to severe chronic pain due to osteoarthritis of the knee, according to results presented here at the American Association of Neurology (AAN) 60th Annual Meeting.
Tapentadol is a novel centrally acting analgesic with a dual mode of action -- mu-opioid receptor agonism and norepinephrine reuptake inhibition.
Christine Rauschkolb-Loeffler, MD, PhD, Senior Director and Team Leader for Compound Development, Johnson & Johnson Pharmaceutical Research & Development, Titusville, New Jersey, and colleagues randomised and titrated 670 patients to a twice-daily maintenance dose of tapentadol ER 100 mg, tapentadol ER 200 mg, oxycodone CR 20 mg, or placebo over 28 days.
"Although opioids can be effective for the treatment of chronic pain, health care providers may be hesitant to prescribe opioids for this purpose for various reasons," Dr. Rauschkolb-Loeffler noted in her presentation on April 15. "One possibility is that opioids are associated with an increased incidence of gastrointestinal and nervous system side effects. Therefore, a need exists for an analgesic that is effective for the treatment of chronic osteoarthritis pain that offers better tolerability than current treatment options."
All patients had a clinical diagnosis of osteoarthritis of the knee based on American College of Rheumatology criteria and functional capacity classes I to III.
The primary efficacy endpoint was average pain intensity based on a 100-mm visual analog scale in the 24 hours prior to the final visit.
Least-squares adjusted mean difference in average pain intensity from placebo was significant for tapentadol ER 200 mg (-8.4 mm; P = .021). Least-squares adjusted mean difference in average pain intensity from placebo was -5.9 mm for tapentadol ER 100 mg (P = .187) and -5.4 mm for oxycodone CR 20 mg (P = .217).
The results thus demonstrate a similar efficacy outcome for tapentadol ER 100 mg and oxycodone CR 20 mg.
The most frequently reported adverse effects for all groups included gastrointestinal and nervous system disorders. Gastrointestinal disorders occurred in 23% of placebo patients, 30% of tapentadol ER 100-mg-treated patients, 49% of tapentadol ER 200-mg patients, and 56% of patients on oxycodone CR 20 mg
Constipation was much less common in the tapentadol ER 100-mg and 200-mg groups than in the oxycodone CR group.
Nervous system disorders were reported by 15%, 24%, 34%, and 43% of patients for placebo, tapentadol ER 100 mg, tapentadol ER 200 mg, and oxycodone CR 20 mg, respectively.
"Overall, the results show that tapentadol ER 200 is effective for up to 4 weeks in patients with moderate to severe chronic pain due to osteoarthritis of the knee," Dr. Rauschkolb-Loeffler pointed out. "Also, tapentadol ER 100 mg was associated with an efficacy outcome similar to oxycodone HCl CR 20 mg."
Osteoarthritis is the most common form of arthritis.
The study was funded by Johnson and Johnson Pharmaceutical Research and Development LLC and Grunenthal GmbH.
[Presentation title: Efficacy and Tolerability of Tapentadol for Relief of Moderate-to-Severe Chronic Pain Due to Osteoarthritis of the Knee. Abstract P03.154]
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