Could A Drug Work So Well That It Causes More Harm? Tanezumab Proves The Answer Is Yes!

(December 16, 2011) An experimental pain-relieving drug has yielded an unexpected finding for patients with osteoarthritis (OA).  It’s not that the drug does not work; indeed, it appears to be remarkably effective against pain in many patients with arthritic knees.  So what’s the downside? Well, in some patients, the drug masked joint pain so incredibly, patients never felt the warning signs or signals that they were over-doing it – and suffered permanent joint destruction, as a result.

 

In the search for a pain reliever with minimal side effects, researchers have been focusing on a chemical known as a nerve growth factor.  The experimental drug in this study focuses on inhibiting nerve growth factor. It’s effect is quite significant, due to the fact that about 27 million American adults suffer the effects of wear and tear on joints. Many sufferers seek pain relief from a non-narcotic medication. Doctors always strive to reduce chronic pain, but they need to preserve at least some pain, as it is the body’s way of warning us that there is tissue damage or bone injury. It is nice for doctors to help patient’s cope with the pain, but not to the point where their ability to feel pain is impaired and places them in danger. Sometimes, a little pain is a good thing. The drug that worked “too well” – Tanezumab – is among a class of targeted treatments using monoclonal antibodies that latch onto a specific target, in this case, nerve growth factor, and neutralize it.

 

Tanezumab was developed by Pfizer, Inc. as a treatment for pain. In 2009 there was a Phase III trial for knee pain due to osteoarthritis (OA). Another Phase III trial for hip pain in OA was halted in June 2010 when some patients needed hip replacement surgery.

 

Pfizer has suspended dosing and recruitment of patients in all ongoing studies in OA, low back pain and neuropathic diabetes pain with Tanezumab.  The FDA put the clinical hold after reports of worsening of OA in some patients resulting in surgery and joint replacement. Trials in other indications for pain relief continue and are not affected.

 

Researchers in the New England Journal of Medicine say the FDA requested Pfizer halt its phase III study of drugs to treat osteoarthritis (OA) after 16 patients’ knee problems worsened, leading to joint replacement surgery. The drug inhibits the production of nerve growth factor, which stimulates nerve development, triggers pain, often present in arthritic joints. Researchers believe the pain relief achieved from Tanezumab was so extraordinary that the patients increased their physical activity enough to accelerate significant joint damage, ultimately causing the need for joint replacement.

 

Pfizer Inc. has suspended its clinical trials of the experimental osteoarthritic drug Tanezumab, effective immediately after finding that a small number of patients taking this drug experienced worsening of their condition, which required joint replacement surgery. The announcement comes less than a week after Pfizer presented positive data at a European medical meeting, showing that Tanezumab significantly reduced knee pain better than a placebo in patients with OA.

 

The drug is also being tested as a treatment for cancer pain, interstitial cystits, chronic low back pain, and diabetic nerve pain. The worsening of condition has not been observed as of yet in non-osteoarthritic patients taking Tanezumab, says Pfizer, so these clinical trials will continue.

 

A few people with OA have advocated the use of Tanezumab, regardless of its “over-corrective” side effects. One person said that he recently had total knee arthoplasty surgery for knee necrosis and advanced OA. He complained of pain as a 9 out of 10 on the Visual Analogue Scale; pain to the point where walking was almost impossible and he had to go to an emergency clinic for roughly thirty morphine injections! And this man was only  55 when he made this report in 2010, not an elderly man by any means. He strongly contests that he would have preferred Tanezuman, even with the possibility of over-exerting his joints. He adds, “sooner or later a patient suffering from a knee at a certain age should have the operation anyway. Better to have no pain (they are unbearable) and risk of having an operation earlier. [My] operation was inevitable anyway, and I wish this drug was available.”

 

Another person on a Tanezumab forum wrote, “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 IV injection gave me four months of pain free living. I was in heaven. When the pain started edging back, I went in and was told it was taken off the market.”

 

So, what do you think should be done with this drug? Two people who have either used Tanezumab or had heard of it regret it being taken off the market. People who need this drug are to the point where their knees are in such bad shape, surgery is inevitable anyway. Living with unbearable pain, sometimes to the point where they can no longer walk, and only delaying the surgery by a few years, or maybe even months. Is it worth it? It’s easy to play devil’s advocate with healthy, pain-free knees. But the people who need the drug know of it’s risks and still opt for it, so what does that really say?

 

This is a topic where discussion is warranted. Feel free to leave your thoughts and comments. You can stop by our Facebook page or Retweet this article. Feel free to contact one of our attorneys at 1-800-246-HURT (4878) or stop by our website.

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