This is a double-blind, randomized, multicenter, noninferiority, phase 2 study. Subjects will discontinue current medications (NSAID or COX-2 inhibitor) 5-14 days prior to randomization. Paracetamol (acetaminophen; ≤2 gm/day) may be used for breakthrough pain. Other NSAIDs, COX-2 inhibitors, opioids, and corticosteroids may not be used at any time during this study. Only subjects recording average WOMAC pain score of 4 to 8 on a 0-10 numerical rating scale during the washout period and meeting all other inclusion criteria will be randomized into the study.