Efficacy of Flavocoxid 500 mg Compared With Naproxen 500 mg in Subjects With Moderate-severe Osteoarthritis of the Knee

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.

Eligibility Criteria:
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.