Osteoarthritis is the most common form of arthritis, affecting more than 21 million Americans, mainly adults over age 45. Women are more susceptible to this condition. Osteoarthritis affects the fingers, spinal column and weight-bearing joints such as the hips, knees and feet. The main symptom of osteoarthritis is pain, the degree of which ranges from mildly inconvenient to debilitating. The estimated U.S. market size for treatment of osteoarthritis is $5+ billion annually. By 2030, an estimated 67 million Americans aged 18 years or older will have doctor-diagnosed arthritis.
For some patients with osteoarthritis, relief of mild-to-moderate joint pain is afforded by acetaminophen or an NSAID. A topical medication without systemic absorption and systemic side effects would be advantageous. An alternative approach to oral agents is the use of intra-articular therapy such as hyaluronic acid, but the efficacy of this treatment is very modest. In patients with osteoarthritis of the knee who have moderate-to-severe pain, and in whom signs of joint inflammation are present, intra-articular glucocorticoids can also be used.