An experimental drug from Indianapolis-based Eli Lilly and Co. and Pfizer Inc. eased arthritis pain in hard-to-treat patients without major safety concerns, a key step in creating a new class of medications that may one day offer an alternative to narcotics.
This is a rare turnaround for a trial that was halted twice because of serious side effects. In the study, a closely watched complication of joint damage emerged at lower-than-anticipated levels, especially for patients getting a higher dose of the injection.
More data will be needed to make the drug a viable option to replace opioids, in part because the complication—rapidly progressive osteoarthritis—still affected about one in 100 patients. The study, presented at the American College of Rheumatology meeting in Chicago, is the first of six pivotal trials designed to suss out safety and effectiveness of the treatment, tanezumab.
The drug is part of a class of medicines known as nerve growth factor inhibitors, thought to work by preventing pain signals triggered by an injury from reaching receptors in the brain. Regeneron Pharmaceuticals Inc. and Teva Pharmaceutical Industries Ltd. are developing similar medications, in a potential market that could generate $10 billion to $15 billion in annual sales based on Goldman Sachs estimates.
“The results demonstrated by tanezumab in this study are particularly meaningful, given that patients had moderate-to-severe pain and were unable to achieve adequate pain relief with other treatment options, including opioids and NSAIDs,” which include drugs like ibuprofen, said Ken Verburg, leader of the drug’s development at Pfizer.
There have been few advances made in the treatment of pain in recent years, and the pharmaceutical industry is searching for nonaddictive alternatives to narcotics as the opioid epidemic continues to sweep the U.S.
Rapidly progressing osteoarthritis in some patients was the reason why the U.S. Food and Drug Administration halted the tanezumab trial in 2010. It was put on hold a second time in 2012 along with similar studies for an unrelated reason and resumed again in 2015.
In the study of 696 patients presented Tuesday, the complication developed in 1.3 percent of patients getting the injection. That was lower than the rate thought to be acceptable by Goldman Sachs analysts to eventually get approval, although none of those given a placebo suffered from the side effect.
The more severe form, which includes damage to the joint, emerged in 0.9 percent of those given the lower dose and none of those in the high dose. The less severe form, marked by accelerated joint space narrowing, occurred in 1.3 percent of the lower dose group and 0.4 percent in the higher dose.
Patients who got tanezumab had significantly greater pain relief and improved physical function than those given a placebo on three separate measures. After four months, 57 percent of patients given the highest dose had their pain levels cut by half, compared with 55 percent of those given a slightly lower dose and 38 percent of those on placebo.
Patients in the trial, who had moderate to severe osteoarthritis of the hips or knees, weren’t allowed to use other medications to treat their pain within 48 hours of getting their symptoms tests, though they could take acetaminophen most other days. All had previously tried a range of therapies that failed to keep their pain under control. Pfizer and Lilly are conducting additional trials to see how tanezumab’s potency compares to other active pain medications, with results expected by the middle of next year.
Tanezumab is injected once every eight weeks, so patients in the trial received two doses. They were followed for an additional 24 weeks to see if any other safety issues emerged. Joint replacement were more common in those given tanezumab than those on placebo, with 3.5 percent and 6.9 percent of patients on active medicine getting new joints compared to 1.7 percent of those on placebo.
Pfizer and Lilly are also testing the injection in some of the most vexing types of pain, including for patients with chronic back pain and cancer pain that stems from metastases in the bones, two groups that currently rely heavily on narcotics.
Tanezumab was discovered by Rinat Neuroscience Corp., a San Francisco biotech start based in San Francisco. Pfizer bought Rinat in 2006 and entered a joint agreement with Lilly in 2013 to jointly development and commercialize the drug.