The objective of this study was to to evaluate the efficacy and safety of PG201 in osteoarthritis patients.

This clinical study was designated to be non-inferiority test with level of significance: 95%, α=0.05. Type 2 error (β) was set as 0.2, and the power of the test was set as 80%. Assuming 20% drop-out rate, the number of subjects required for each treatment group was estimated to be 154, while the total number of subjects required for the study 308.

non-inferiority margin: 8mm

Patients in the PG201 group were prescribed two PG201 tablets per day(BID) and one celecoxib placebo capsule each in the morning and evening per day for 8 weeks.

Patients in the celecoxib group were prescribed celecoxib 200 mg (one 200 mg capsule and one celecoxib placebo capsule) and one PG201 placebo tablet each in the morning and evening per day for 8 weeks.

Inclusion Criteria:

1. Patients ≥40 and ≤ 80years of age.

2. Patients who meet the American College of Rheumatology clinical plus radiographic classification criteria for idiopathic osteoarthritis of the knee, which are defined as follow:

   a patient who had knee pain and radiographically diagnosed osteophytes and met at least one of the followings.

   • Age> 50 years.
   • Morning stiffness for less than 30 minutes.
   • Crepitus during movement of the weight-bearing knee.

3. Patients with symptomatic primary osteoarthritis of the knee at least in the last 3 months prior to screening.

4. Patients who received Nonsteroidal antiinflammatory drugs (NSAIDs)/Cyclooxygenase-2 inhibitor for the treatment of arthritis of the knee for at least 5 days a week during 4 weeks prior to screening.

5. Patients who had a score of 100mm pain VAS ≤80 mm at screening.

6. Patients who had a score of 100mm pain VAS ≥50 mm at baseline.

7. Patients should be able and willing to provide the written informed consent.

Exclusion Criteria:

1. Patients with a history of surgery or arthroscopy of the study joint within the previous 6 months.
2. Patients with trauma of study joint within the previous 12 months.
3. Patients with symptomatic hip osteoarthritis, other condition that would interfere with study assessments.
4. Patients with any other type of arthritis, active malignancies or any active GI, cardiovascular, renal, hepatic, neurologic, or psychiatric disease.
5. Patients with a known hypersensitivity or intolerance to Nonsteroidal antiinflammatory drugs (NSAIDs), aspirin or Cyclooxygenase-2 inhibitor.
6. Patients with uncontrollable hypertension.
7. Patients with any of creatinine, bilirubin, Alanine aminotransferase or Aspartate aminotransferase > 1.5 times the Upper Lange of normal at screening.
8. Patients with a history of drug or alcohol abuse.