According to a 2023 study published in The Lancet Rheumatology, nearly 1 billion people worldwide will be affected by the most common form of arthritis: osteoarthritis. Currently, the condition affects 15 percent of the global population over age 30, with factors like aging and obesity pushing that number higher and higher. The condition occurs in the knee when cartilage breaks down and allows your bones to rub together, leading to pain, stiffness, and swelling. Several different treatments are available, including non-surgical options, injections, and surgery, but findings from a new study suggest that there might be yet another route for patients: semaglutide. The medication is best known by Novo Nordisk's brand names Ozempic (approved for type 2 diabetes) and Wegovy (approved for obesity), which are both glucagon-like peptide-1 inhibitors (GLP-1s).
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The study, which was run by Novo Nordisk and published in The New England Journal of Medicine, outlined results from the STEP 9 trial, which included 407 adults with obesity and moderate knee osteoarthritis. Patients had an average baseline weight of 239.5 pounds and were either given a 2.4-mg weekly dose of semaglutide in the form of Wegovy or a placebo for 68 weeks.
At the start of the study, participants had an average score of 70.9 out of 100 on the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC).
"They were really in pain. They can't exercise. You are trapped in knees like this," lead study author Henning Bliddal, MD, MSci, a rheumatologist at the Parker Insitute at Copenhagen University Hospital in Denmark, told The New York Times.
However, after 68 weeks, participants who took semaglutide reported an average reduction of 41.7 points, while those who received the placebo had a reduction of 27.5 points.
According to Bliddal, the 41.7-point drop "is huge," and as David T. Felson, MD, MPH, a rheumatologist at Boston Medical Center, told the NYT, the pain reduction was also more significant than what doctors see with other treatments (aside from knee replacement surgery).
Bliddal continued, "To be frank, this is what we had hoped for. But it even exceeded our expectations."
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In addition to the reduction in pain, patients who took semaglutide had a 13.7 percent reduction in body weight at week 68, while those who received the placebo only saw a 3.2 percent reduction. Those in the treatment group also had a larger improvement in physical function scores compared with the placebo group.
In a press release outlining study findings, Bliddal pointed out that the risk of developing knee osteoarthritis is four times higher for people with obesity, and as the condition can impact critical daily functions, weight loss is often recommended as a treatment approach for symptoms.
However, this can be "challenging," which is where an option like semaglutide could help.
"Obesity is a complex metabolic disease associated with multiple co-morbid conditions, including knee osteoarthritis," Anna Windle, PhD, senior vice president of Clinical Development, Medical Regulatory Affairs at Novo Nordisk, said in the release. "The STEP 9 results are encouraging and provide important information about the effect of semaglutide, a glucagon-like peptide-1 receptor agonist, on knee osteoarthritis outcomes in people with obesity. We look forward to working with regulatory authorities on next steps based on these findings."
