According to the Associated Press, a class of experimental arthritis drugs such as Pfizer’s drug tanezumab, has been sidelined due to links to bone decay by the FDA.
The Food and Drug Administration says there is a clear association between the nerve-blocking medications and incidences of joint failure that led the agency to halt studies of the drugs in 2010.
Drugmakers once touted the drugs, known as nerve growth factor inhibitors, as a potential breakthrough for treating osteoarthritis, back pain and other chronic pain conditions. For more than a century doctors have treated pain with familiar painkillers like aspirin and Advil, or powerful opiate-based drugs. Both approaches can be problematic. Anti-inflammatory painkillers like Advil can cause stomach bleeding, while opiates carry a high risk of addiction.
The injectable nerve-silencing drugs offered a new approach, by blocking proteins that control pain sensations throughout the body.
But problems with the drugs began to emerge in the summer of 2010. Beginning in June, Pfizer halted studies of its experimental injection tanezumab in patients with osteoarthritis, low back pain and diabetic nerve pain. The action was requested by the Food and Drug Administration, after researchers reported that osteoarthritis actually worsened in some patients, causing joint failure in some cases.
In December the FDA put a research hold on all drugs in the class after similar problems emerged, halting studies by Johnson & Johnson and Regeneron Pharmaceuticals Inc.
Regeneron was developing a compound called REGN475 in cooperation with Sanofi-Aventis. Johnson & Johnson was testing its drug fulranumab in several pain conditions. The FDA lifted its hold on a trial of the drug for cancer pain last summer, though studies for osteoarthritis remain on hold.
The drugmakers are expected to argue Monday that the joint deterioration was caused by a rare drug side effect caused by patients taking multiple painkillers simultaneously. According to briefing materials, Pfizer and J&J both found that the bone problems almost exclusively occurred in patients taking the experimental drugs along with traditional anti-inflammatory painkillers like aspirin and Advil.
The FDA’s analysis published Thursday supports that theory, noting that the side effects were worst among patients taking both nerve-blocking drugs and older painkillers. However, the agency notes that Pfizer’s tanezumab was associated with significant bone problems even when used alone. The FDA analyzed nearly 500 cases of bone damage reported by all three drugmakers studying the medications.
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