Tanezumab Highly Effective for Osteoarthritis in Halted Trial
Researchers writing in the New England Journal of Medicine highlight the effectiveness of the drug tanezumab for treating osteoarthritis pain. The trial was stopped during Phase II clinical testing because some patients experienced worsening of the disease. Following the trial's cessation, scientists say they found the drug worked extremely well and had few side effects that were minor. The trial was stopped at the request of the FDA.
The scientists say tanezumab, a humanized monoclonal antibody, "is a very effective drug for relieving pain." In the 16 week Phase II clinical trial, patients with osteoarthritis experienced increased mobility and pain relief. Other studies, conducted over a longer period, indicated the drug might cause progression of the disease. Whether trials will continue depends on a review by the FDA who will determine if the drug is safe.
According to Nancy E. Lane, professor of internal medicine and director of the UC Davis Center for Healthy Aging, principal investigator and co-author of the study, "The need to find new drugs to treat osteoarthritis is critical. We really don't have anything that slows its course, and most people with severe disease end up dependent on narcotic analgesics while waiting to have a joint replaced." She also says the effect of the drug was remarkable. "People on the drug went from having very limited activity to practically being on the dance floor. No medication available today has such dramatic results."
Tanezumab could still emerge as osteoarthritis treatment
The FDA is reviewing the safety of tanezumab that could still emerge as an effective treatment for the pain of osteoarthritis. In the Phase II study, side effects were minor, temporary and primarily seen in patients receiving higher doses of the drug. The ratio of side effects was 68 percent in the drug group and 55 percent for the placebo arm of the trial.
The trial was halted when some patients developed worsening osteoarthritis in the hips and shoulders, but Lane says "I believe that the apparent worsening of certain patients' condition may be due to the fact that tanezumab works so well. People feel so much better that they become more active, putting increased stress on their already badly diseased joints." She emphasizes that the drug may not be safe for advanced forms of the disease, making screening for appropriate candidates important.
Tanezumab study results compelling
Nine percent developed headache, 7 percent cold-like symptoms, 7 percent abnormal sensation (paresthesia) and "some" developed decreased tendon reflexes. Among 450 patients randomized to receive tanezumab, pain was reduced by 62 percent for the drug and 22 percent for placebo.
Serious problems associated with current medications known as COX2 inhibitors, combined with the compelling and "remarkable" results from tanezumab could mean the drug would be approved by the FDA for phase III clinical trials. "Unfortunately, it appears some people go on to have their osteoarthritis progress more quickly. The long-term safety of tanezumab needs to be better understood", says Thomas J. Schnitzer of Northwestern Medicine in Chicago.
When it comes to treating osteoarthritis that affects more than 20 million people in the United States, Schnitzer explains, "We really don't have anything that slows its course, and most people with severe disease end up dependent on narcotic analgesics while waiting to have a joint replaced." The researchers also note that communication between the study authors, the FDA and the drug company has been exemplary, saying, "This is how drug development should be carried out".