PH-797804 is a potent inhibitor of inflammatory mediators that have a potential role in pain signalling following nerve injury and inflammation. Blocking such mediators may potentially have a therapeutic benefit by reducing pain.

Inclusion Criteria:

• Male or female subjects between, and including, the ages of 18 and 75 years. Females must be of non-childbearing potential.
• Diagnosis of osteoarthritis of the knee based on American College of Rheumatology criteria with X-ray confirmation (a Kellgren-Lawrence X-ray grade of ≥2.

Exclusion Criteria:

• History of diseases other than osteoarthritis that may involve the index knee.
• Other severe pain that impairs the assessment of osteoarthritis of pain.
• Electrocardiogram abnormalities.
• History of gastrointestinal disorders.