New Research on Osteoarthritis: A Report from the American College of Rheumatology Meeting
I have more than a few osteoarthritis patients who are somehow under the impression that researchers have given up on them. These are people with chronically painful joints who still recall those heady days of the Cox-2 inhibitors--the "super anti-inflammatories" as the media so liked to call Vioxx, Bextra and Celebrex. Alas, their hopes were dashed with the withdrawal from the market of Vioxx and Bextra; and the lingering fears regarding Celebrex.
Well, maybe that was a ray of hope I saw fighting its way through the early morning fog in San Francisco last week. There is still research being done to find new ways to treat the chronic pain associated with osteoarthritis.
The results of a study exploring the safety and efficacy of tanezumab for the treatment of moderate to severe osteoarthritis knee pain were presented. Tanezumab is a humanized monoclonal antibody that acts on nerve growth factor, a biochemical released at the site of injury and inflammation.
For this study, tanezumab was given intravenously at day 1 and day 56 of the study. The researchers noted improvement in knee pain, physical function, and stiffness scores, compared to those study subjects taking the placebo. Pain relief lasted throughout the 16-week trial. Walking knee pain was reduced by as much as 62%, compared to just 22% for placebo.
It should be noted that most of the patients in this study had fairly severe knee pain, and were essentially candidates for artificial knee replacement surgery.
However, there were side effects. In this study, the most common side effects associated with tanezumab included headache, upper respiratory tract infection, abnormal sensations such as numbness and tingling, decreased sensation for touch, and joint aches. There appeared to be more side effects at the higher dosage range of the several doses studied. The neurologic side effects (the abnormal sensations and the decreased sense of touch) were short-lived, and apparently no study subject had to withdraw from the study due to these side effects. Still, whenever there is a neurologic side effect, such as these changes in sensation, doctors become concerned.
Obviously, this new biologic for osteoarthritis will need to be studied further. But these results are certainly intriguing. We are so used to talking about biologics for rheumatoid arthritis; it is certainly refreshing to see cutting-edge science applied to osteoarthritis.
Before I leave the topic of the chronic pain of osteoarthritis, I should remind everyone again that Celebrex is still the last Cox-2 available in the United States, and apparently alive and well.
Another study presented at last week's meeting in San Francisco reported on the continuous use of daily Celebrex over a 22-week period compared to just occasional use of Celebrex in preventing spontaneous flares of osteoarthritis. It concluded that continuous use of Celebrex resulted in 42% fewer osteoarthritis flares, compared to the occasional, "as needed" use of Celebrex. Further, there were no significant differences in the number of side effects between those who took occasional Celebrex and those who took it religiously.