MRI Study to Evaluate the Safety and Efficacy of SM04690 for Knee Osteoarthritis

Inclusion Criteria: * Ambulatory (single assistive devices such as canes allowed if needed less than 50% of the time, subjects requiring a walker are excluded) * Diagnosis of femorotibial OA in the target knee by standard American College of Rheumatology (ACR) criteria at the Screening Visit (clinical AND radiographic criteria); OA of the knee is not to be secondary to any rheumatologic conditions (e.g., rheumatoid arthritis) * Pain compatible with OA of the knee(s) for at least 26 weeks prior to the Screening Visit * Primary source of pain throughout the body is due to OA in the target knee * Daily OA knee pain diary average Numeric Rating Scale (NRS) intensity score ≥4 and ≤8 in the target knee on the 11-point (0-10) NRS scale for the 7 days immediately preceding Day 1 * Pain NRS scores recorded for the target knee on at least 4 out of the 7 days immediately preceding Day 1 * Daily OA knee pain diary average NRS intensity score \<4 in the non-target knee on the 11-point (0-10) NRS scale for the 7 days immediately preceding Day 1 * Pain NRS scores recorded for the non-target knee on at least 4 out of the 7 days immediately preceding Day 1 * Baseline mJSW by radiograph between 2 and 4 mm, inclusive, in the target knee at the Screening Visit as assessed by independent central readers * Total WOMAC score of 96-192 (out of 240) for the target knee at Day 1 regardless of if the subject is on symptomatic oral treatment * Negative drug test for amphetamine, methamphetamine, bupren…