A walking model to assess the onset of analgesia in osteoarthritis knee pain.
Author(s): Peeva E, Beals CR, Bolognese JA, Kivitz AJ, Taber L, Harman A, Smugar SS,
Moskowitz RW.
Affiliation(s): Clinical Research, Merck Research Laboratories, Rahway, NJ 07065, United States.
elena_peeva@merck.com
Publication date & source: 2010, Osteoarthritis Cartilage. , 18(5):646-53
OBJECTIVE: To assess a walking model utilizing a set of standardized treadmill
walks to measure acute analgesic response in osteoarthritis (OA) of the knee.
DESIGN: Randomized, double-blind, placebo-controlled, multiple dose, three-period
crossover study. Patients > or =45 years of age (N=22) with symptomatic knee OA
were randomized to naproxen 500 mg bid, tramadol/acetaminophen 37.5 mg/325 mg in
forced titration, or placebo in each of three periods. Patients performed
multiple 20-minute treadmill walks on Day 1 and Day 3 at a consistent
self-selected pace predetermined at screening. Pain intensity (PI) during the
walks was assessed on an 11-point numerical rating scale at 0, 3, 6, 9, 12, 15,
18, and 20 min. The primary endpoint was the time-weighted average (TWA) change
from baseline PI on Day 3 for the two self-paced walks for the active treatments
vs placebo. Time to moderate pain (TTMP) was a key secondary endpoint.
RESULTS: Compared with placebo, the TWA change from baseline PI on Day 3 was
significantly better with tramadol/acetaminophen (P=0.043) but not with naproxen
(P=0.089). TWA change from baseline on Day 1 was also significantly better with
both tramadol/acetaminophen (P=0.001) and naproxen (P=0.048) compared with
placebo. TTMP was significantly better for tramadol/acetaminophen and naproxen
than placebo (P<0.001 to P=0.015) for walks on Day 1 after a single dose and on
Day 3.
CONCLUSIONS: This novel OA pain model was able to discriminate both
tramadol/acetaminophen and naproxen from placebo after single and multiple doses.
ClinicalTrials.gov identifier: NCT00772967.
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