When it comes to the pain caused by knee osteoarthritis, there is a great need for an effective drug that doesn't cause dependency, because many patients either cannot tolerate, or don't obtain sufficient pain relief from traditional nonsteroidal anti-inflammatory medication. Finally, there may be a solution: Tanezumab.
According to Nancy E. Lane, M.D., Professor of Medicine and Rheumatology at the University of California at Davis Medical Center, and Director of their Center for Healthy Aging, a Phase II clinical trial of tanezumab has shown that treatment once every eight weeks significantly reduces pain in patients with moderate to severe knee osteoarthritis
Dr. Lane and her colleagues followed 444 men and women aged 40-78 who were unable to control their pain with non-steroid anti-inflammatory medication, such as ibuprofen or naproxen, or who were candidates for more invasive treatments such as total joint replacement.
The patients enrolled in this 16-week study were treated with either tanezumab or a placebo. Tanezumab is a humanized monoclonal antibody against nerve growth factor, or NGF. NGF stimulates the growth of sensory nerve cells and increases the body's response to pain. Tanezumab appears to block the pain signals.
Tanezumab was intravenously administered at 10, 25, 50, 100, or 200 µg/kg on days 1 and 56 of the study. The researchers measured effectiveness by evaluating knee pain with walking and patient assessment of response to the treatment as well as other outcome measures, including stiffness and physical function.
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The results: Tanezumab significantly improved knee pain and the patients' overall assessments of their condition by 46% to 62% compared with 22% for those patients given placebo. At weeks 12 and 16, researchers noted a significant improvement in the secondary outcome measures, including pain, physical function, and stiffness. Within three days of the first dose of tanezumab, many patients in Dr. Lane's study experienced a greater-than-50% improvement in walking knee pain. At higher doses, there was a 70 to 80% drop in knee pain that continued over the next two months.
Based on these interesting study findings from Dr. Lane, it is clear that inhibition of NGF may provide a novel type of therapy to reduce the pain of osteoarthritis and possibly other pain conditions, including fibromyalgia, metastatic cancer pain, and degenerative disease pain.
