(DAVIS, Calif.) -- An experimental drug for patients with osteoarthritis has yielded an unexpected finding. The drug appears to be effective against pain in many people with arthritic knees, but in some patients, it blunted joint pain so powerfully they never felt the warning signs they were overdoing it and suffered joint destruction as a result.
In the quest for new pain relievers with minimal side effects, researchers have been focusing on a chemical known as nerve growth factor, which has been associated with increased pain from a variety of injuries and inflammatory conditions. The experimental drug in this study aims to inhibit nerve growth factor. Its effect is significant, especially in light of the prevalence of osteoarthritis, a common result of excessive wear-and-tear on the joints, which plagues an estimated 27 million American adults. Many sufferers seek pain relief from non-narcotic medications.
"This is a radical notion for most people: that pain can be protective, but if you think about it, without pain signals, we would injure ourselves all the time" said Dr. Jack Choueka, chairman of orthopedics at Maimonides Medical Center in Brooklyn, N.Y., who was not involved in the study. "Doctors strive to reduce chronic pain, but they need to preserve at least some of it. It is the body's way of putting up a red flag warning about imminent tissue damage, Choueka said. "So it's important for doctors to help patients cope with pain, but not to the point where their ability to feel pain is impaired and places them in danger. Ergo: a little pain is a good thing."
The drug that worked "too well," tanezumab, is among a class of targeted treatments using monoclonal antibodies that latch onto a specific target, in this case nerve growth factor, and neutralize it.
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