Osteoarthritis is a serious disease that affects millions of people worldwide, but until recently had no licensed treatment to modify the disease.[1] Available pain relievers are only moderately effective and cause significant side effects. A breakthrough discovery in 2010 was the development of a monoclonal antibody targeting nerve growth factor (NGF), which is considered the most important clinical advance in the treatment of osteoarthritis since the 1960s, when surgical joint replacements began to be used. This anti-NGF antibody achieved a level of pain relief that surpassed all previously licensed osteoarthritis pain medications. In addition to its effectiveness in treating pain, this antibody has also contributed to a better understanding of the mechanisms by which osteoarthritis causes pain.