Multi-Center Study Evaluating the Efficacy of Wobenzym(R)N in Treating Knee Osteoarthritis

Inclusion Criteria: * Ambulatory outpatients of either sex, between 45 and 80 years of age, inclusively, with primary OA of the knee meeting the classification criteria set by the American College of Rheumatology (ACR; Appendix C.1), and who are not expected to require surgical treatment for at least three (3) months after inclusion (Visit 1). * Women of childbearing potential must agree to use an adequate contraception (abstinence; device mechanical barrier contraception; male partner sterilized) beginning at least seven days prior to treatment (oral birth control pill should begin at least 4 weeks prior to treatment) and continuing at least 14 days after Visit 4 or the discontinuation visit. A serum or urine pregnancy test will be performed at Visit 1. * Functional Capacity Classification (Appendix C.2) of I-III at Visit 1. * Except for OA, the subject is judged to be in otherwise general good health based on medical history, physical examination, and routine laboratory tests (Appendix B). * Subjects with a WOMAC pain subscale index of at least 40 mm and less than or equal to 90 mm (VAS) at the Baseline Visit after a 24-hour washout of any analgesics and a minimum of 7 days washout of any NSAIDs (Appendix C.3 \& 4). * Subjects with OA of the contra-lateral knee will be included provided contra-lateral knee OA pain intensity is inferior to the index knee. * Able to understand and complete study questionnaires including questions requiring a visual analog scale (VAS) response (Appendix C.4). * Willing to participate in this study for approximately ten weeks. * Written informed consent obtained. * Subject agreed to follow the protocol. Exclusion Criteria: * Any contraindication to the use of Wobenzym® N (including allergy). * Concurrent medical/arthritic disease that could confound or interfere with the monitoring of efficacy including, but no limited to: Inflammatory arthritis (e.g., rheumatoid arthritis), systemic lupus, spondyloarthropathy, psoriatic arthropathy, Reiter's syndrome, ankylosing spondylitis, arthritis associated with inflammatory bowel disease, polymyalgia rheumatica and gout or pseudogout of the index knee, Paget's disease affecting the study joint, a history of septic arthritis or intra-articular fracture of the study joint, osteochondritis, dessicans or osteonecrosis of the study joint, Wilson's disease, haemochromatosis, ochronosis, chondrocalcinosis or primary osteochondromatosis. * Significant injury of the study joint within three months of the Baseline visit as per investigator judgment. * Subjects with Class IV functional capacity using the ACR criteria. * Subjects who had meniscal surgery on the study knee. * Subjects who have undergone total joint replacement of the contra-lateral knee within six months prior to the Screening Visit (Visit 1). * Any clinical signs or laboratory evidence for severe renal/liver/pulmonary, neurological, cardiovascular, metabolic, haematological, or psychiatric condition which in the Investigator's opinion contraindicates a 6 week course of therapy with Wobenzym® N. * Subject is, in the opinion of the investigator, mentally or legally incapacitated preventing informed consent from being obtained, or cannot read or comprehend written material. * Active malignancy of any type or history of a malignancy within the last five years other than basal cell carcinoma. * Any active gastrointestinal disease. * Use of NSAID within seven days of entering the study (Visit 2). * Use of glucosamine sulphate, chondroitin sulphate or any other natural health product and/or OTC product that claim to be effective for pain and/or OA within 30 days of entering the study (Visit 2). * History of drug abuse or active alcoholism. * Any investigational drug within 30 days prior to screening.