To compare flavocoxid with naproxen for patients with moderate to severe osteoarthritis of the knee.

Efficacy of flavocoxid 500 mg compared with naproxen 500 mg in subjects with moderate-severe osteoarthritis of the knee.

Inclusion Criteria:

• Willing and able to read and understand informed consent and questionnaires in English.
• Adults of either gender age 35-75 years, in general good health.
• Established X-ray diagnosis of osteoarthritis of at least one knee.
• Taken NSAID including COX-2 (cyclo-oxygenase-2) inhibitor in full therapeutic dose for at least one month prior to screening.
• Able and will to discontinue osteoarthritis medications until flare criteria met.
• BMI</= 45
• Subjects must rate target knee at least 5 out of 10 on discomfort VAS (visual analogue scale) at baseline visit.
• Have an increase of at least 15mm on a 100mm pain VAS (visual analogue scale) from screening to baseline visit.
• Must use acceptable birth control if female.
• Screening fecal occult must be negative.
• Able to attend all required visits
• Physical Therapy is allowed as long as the type and frequency remains unchanged for the duration of the study.

Exclusion Criteria:

• Refusal to sign consent.
• Inability to attend all clinic visits
• Grade 0-1 K-L changes in both knees or grade 4 K-L changes in either knee on standing A/P radiograph
• Pregnant or lactating women
• History of serious cardio-vascular disease.
• Recurrent arrythmias, except paroxysmal tachycardia, cardiomyopathy, myocardial infarct within one year of screening.
• History of chronic esophageal, gastric or duodenal disease
• History of upper GI bleeding within the past 2 years.
• Any GI disorder associated with malabsorption
• Any musculo-skeletal or neurological condition that results in pain or gait disturbance that might confound evaluation of target knee.
• Uncontrolled Diabetes Mellitus
• History of bleeding disorder or concurrent use of coumadin or any agent used to reduce blood clotting or platelet adhesiveness.
• Concurrent use of any anti-arthritic medication, including corticosteroids regardless of the reason for use. (low dose aspirin for cardioprotection is allowed)
• History of chronic renal disease with creatinine >2.0 or nephrotic syndrome with 24 hour protein excretion >1000mg.
• Intra-articular injection of any hyaluronic acid preparation in the target knee joint within 4 months of baseline visit.
• Intra-articular injection of a corticosteroid in the target knee joint within 2 months of the baseline visit.
• BMI>45
• History of allergic reaction to flavonoid or flavan containing foods or products (example: red wine, colored fruits and vegetable, brazil nuts, tea, natto)
• History of allergy to aspirin, naproxen or other NSAID
• History of substance abuse including alcohol, or any psychiatric condition that may impair the subject's ability to comply with the study requirements.
• Any medical condition that, in the opinion of the investigator, might put the subject at undue risk or might interfere with the subject's ability to participate in the study.
• Participation in another clinical trial within 30 days or 7 half lives of the study agent, whichever is longer, of the screening visit.

interested researchers may contact sponsor

Screening to Week 12