U.S. drug regulators are asking experts for advice on whether companies should restart clinical trials for painkillers that help people with osteoarthritis and other conditions, but can destroy joints.
In a memo posted online Thursday The U.S. Food and Drug Administration said these drugs, from the class of anti-nerve growth factors, "represent a potentially significant and novel strategy for the treatment of pain."
Nerve growth factor (NGF) is associated with nerve pain, but it may also help with wound repair and angiogenesis, the FDA said. The joint problems with the drug may be because it blocks these beneficial effects of NFG, one FDA reviewer said.
In 2010, the FDA halted almost all clinical trials of NGF inhibitors after nearly 500 people taking the drugs in studies needed joint replacement.
Companies were allowed to keep testing the drugs in terminal cancer patients with severe bone pain, since the benefits there may outweigh risks.
Pfizer Inc, Regeneron Pharmaceuticals Inc and Johnson & Johnson are now pitching to resume wider trials, in what could be a multi-billion-dollar pain market.
Outside advisers to the FDA will vote Monday on whether there is a way for trials to move forward, perhaps by limiting the drugs to lower doses, or to only certain conditions with fewer treatment options.
The drugs have been studied for common conditions like low back pain and osteoarthritis. They have also been tested in narrower groups, like people with bladder pain syndrome.
Pfizer was furthest along in development of its biotech anti-NGF drug tanezumab when the FDA asked it to halt trials in June 2010. Pfizer had already reported positive data for the medicine.
"We've had strong results from the clinical program. That's why we're so interested in progressing these compounds forward," Pfizer said in an interview on the advisory meeting. "They have the promise of offering chronic pain patients something they haven't had in the past."
The anti-NGF drugs have the potential to become the first biotechnology drugs specifically for pain.
Several injectable biotechnology medicines are used to treat rheumatoid arthritis. More traditional oral pain killers, such as aspirin, ibuprofen and Pfizer's own Celebrex, are typically used to treat osteoarthritis, but may have side effects such as promoting bleeding.
Anna Yukhananov • Reuters Health Information © 2012