Osteoarthritis is a painful, progressive disease of the joints for which there is no cure. The condition affects more than 32.5 million adults in the United State and the incidence is growing as a result of aging, obesity, and sports injuries. Flexion Therapeutics is developing an experimental gene therapy to treat the condition. Rather than correcting an underlying genetic mutation, the experimental therapy delivered into the joint codes for the production of the anti-inflammatory protein interleukin-1 receptor antagonist. It is expected to deliver as-needed anti-inflammatory activity to joint tissues over the long-term. We spoke to Mike Clayman, co-founder and CEO of Flexion Therapeutics, about osteoarthritis, the problem with existing therapeutic approaches, and the company’s efforts to develop a gene therapy to get the body to produce an anti-inflammatory protein as needed.