Just when I think I’ve found the miracle cure for my low back pain, they take it off the market. I was given tanezumab as an “experimental” drug and had great results. One intravenous injection gave me four months of pain free living. I was in heaven. When the pain started edging back, I went back in and was told it was taken off the market. What happened and will it be brought back? What can you tell me?

As you have personally experienced, chronic low back pain remains a problem without a good solution for some people. No single type of treatment works for everyone. Most patients end up combining multiple different treatments until they find the right mix that is effective for them. This may include medications, counseling or behavioral therapy, physical therapy, and surgery.

Medications often include pain relievers (analgesics) such as tylenol and antiinflammatories such as ibuprofen, naproxen, or other prescription nonsteroidal antiinflammatories (NSAIDs). Sometimes mild narcotics such as codeine or tramadol are prescribed.

The new drug you received called Tanezumab was developed as a treatment for pain. It has been shown effective in patients with osteoarthritis, interstitial cystitis (bladder pain), and bone pain from cancer.

Tanezumab is a monoclonal antibody (mAb) that works to alleviate pain because it neutralizes nerve growth factor (NGF). Nerve growth factor sets up pain signals and even heightens the body’s responsiveness to painful stimuli. This means the nervous system responds faster to smaller inputs creating larger pain responses.

Tanezumab stops nerve growth factor activity. Tanezumab was undergoing Phase II and III clinical trials for the treatment of various pain problems, including chronic low back pain, bone cancer pain, and interstitial cystitis. But as you discovered, studies were halted when some patients with osteoarthritis got much worse after taking tanezumab and ended up needing hip replacements.

The reports included 16 patients who had X-ray evidence of bone necrosis (bone death) that required total joint replacement. It is possible that joint failure occurred as a result of excess wear and tear on the joint when pain was absent. In a sense, tanezumab as a pain reliever may have been too effective for these patients with painful hip and knee osteoarthritis. Eliminating the pain did not stop the degenerative processes and the increased activity further damaged the involved joints.

So for the moment, tanezumab is on regulatory hold due to the adverse effects in osteoarthritis patients. In the meantime, there is enough evidence from other studies that the use of tanezumab is safe and effective with chronic low back pain patients. Many people hope studies of this medication for chronic low back pain will resume if/when the ban on its use in studies is lifted.