Study Comparing a Generic Diclofenac Sodium Topical Gel, 1% to Voltaren in the Treatment of Subjects With Osteoarthritis of the Knee

Inclusion Criteria: * Healthy, ambulatory male or non-pregnant female subjects aged ≥ 35 years with a clinical diagnosis of OA of the knee. * Had an X-ray of the target knee, taken no more than 1 year before baseline, showing evidence of OA with Kellgren-Lawrence grade 1-3 disease. * After discontinuing all pain medications for at least 7 days, has at least moderate pain on movement for target knee * If female and of child-bearing potential, agree to abstain from sexual intercourse or use a reliable method of contraception during the study * Able to tolerate rescue medication with paracetamol/acetaminophen. Exclusion Criteria: * Pregnant or lactating or planning to become pregnant during the study period. * X-ray showing evidence of OA with Kellgren-Lawrence grade 4 disease. * History of OA pain in the contralateral knee requiring medication within 1 year prior to screening. * After discontinuing all pain medications for at least 7 days, has a baseline score of ≥20 mm on a 0-100 mm Visual Analog Scale (VAS) for the contralateral knee immediately prior to randomization. * History of secondary OA, rheumatoid arthritis, chronic inflammatory disease or fibromyalgia. * History of asthma, hypertension, myocardial infarction, thrombotic events, stroke, congestive heart failure, impaired renal function or liver disease. * History of gastrointestinal bleeding or peptic ulcer disease. * Use of warfarin or other anticoagulant therapy within 30 days of study randomization. * Elevated transaminases at screening. * Use of ACE inhibitors, cyclosporine, diuretics, lithium or methotrexate, within 30 days of study randomization. * Concomitant use of corticosteroids or use within 30 days of study randomization. * Concomitant acetylsalicylic acid therapy other than a stable low dose used for cardiac prophylaxis taken for at least 3 months prior to enrollment and maintained throughout the duration of the study. * Known allergy to aspirin or nonsteroidal anti-inflammatory drug * Any other acute or chronic illness that could compromise the integrity of study data or place the subject at risk by participating in the study. * Receipt of any drug as part of a research study within 30 days prior to screening. * Previous participation in this study. * Any use between screening and baseline of a treatment or medication that may potentially confound study assessment that may potentially confound study assessment (e.g. use of topical analgesics or anti-inflammatory drugs). * Recent history of major knee injury or surgery. * Known history of positive HIV