A Study of ABT-652 in Adults With Osteoarthritis Pain of the Knee

Inclusion Criteria * History of OA of the knee joint and meeting American College of Rheumatology (ACR) Clinical and Radiographic criteria, * Pain score as required by the protocol at Screening and Baseline * Willing to washout of analgesics and to follow treatment plan, visit schedules and study procedures. Exclusion Criteria * History of sensitivity to histamine medications, acetaminophen (paracetamol), or non-steroidal anti-inflammatory drugs (NSAIDs) * Active gastrointestinal (GI) disease, GI bleeding or GI ulceration, or history of GI bleeding or GI ulceration in the last 6 months * History of major psychiatric disorders * Diagnosis of rheumatoid arthritis, autoimmune disorder, arthritis other than osteoarthritis involving the study joint, or other painful syndrome that could interfere with the assessment of pain at the study joint * Any cardiac, respiratory, neurological or other medical condition or illness that is not well controlled with treatment