Pfizer Inc.’s best-selling drug, Lyrica, didn’t help patients with the most common cause of back pain any more than a placebo in a small study, casting doubt on the potential for doctors to expand the medication’s use.
In a trial of 29 people over the age of 50 with severe lumbar spinal stenosis, those given Lyrica saw no more improvement than with a placebo, according to research published yesterday in the journal Neurology. Lyrica, also known as pregabalin, is already used to treat pain caused by shingles and diabetes and for conditions including epilepsy, fibromyalgia and hot flashes.
While the FDA has not approved the drug’s use for spinal stenosis, Lyrica and similar medicines are often used to treat lower back pain, according to the study, which was funded by New York-based Pfizer. Sales of Lyrica reached $4.6 billion last year, accounting for 9 percent of Pfizer’s total revenue.
“The core issue is we’re still looking for effective therapies for nerve pain that comes from the spine,” said John Markman, the doctor who led the study. “That is by far the most common reason folks seek care for pain.”
In lumbar spinal stenosis, the canal where spinal nerves pass through the bones of the lower spine narrows because of arthritis, thickening of ligaments or other reasons. The narrowed passage can pinch the spinal nerves, irritating them and causing back pain or burning or tingling in the buttocks or legs. It can be treated through steroid injections to suppress the inflammation or surgery to reverse the narrowing.
Chronic low back pain is orders of magnitude more common than those other types of nerve pain, said Markman, the director of the Translational Pain Research Program at the University of Rochester’s neurosurgery department.
In the study, patients who received a placebo were given an antihistamine that can cause similar side effects to pregabalin, a measure the researchers took to better obscure which patients received the drug being tested, Markman said.
Lyrica has become increasingly important to Pfizer’s earnings since the New York-based company lost patent protection on its cholesterol pill Lipitor, which once generated almost $13 billion a year. In February, Pfizer won a court ruling that will block generic versions of Lyrica until December 2018.
The drug’s reputation may be strong enough to withstand the results of the trial, said Houman Danesh, a specialist in pain management, rehabilitation and physical medicine at New York’s Mount Sinai Hospital.
“Lyrica is viewed as a very powerful nerve pain medication,” said Danesh, who wasn’t involved in the research. “I don’t think people will change their practice based on one study.”