Semaglutide eases knee pain

Osteoarthritis is the joint disease that wears down cartilage, the smooth layer that helps bones glide, and the knee is one of its most common targets. In a 68-week trial, once-weekly semaglutide cut knee pain and improved movement in adults with obesity and moderate knee osteoarthritis. (nejm.org) The STEP 9 trial enrolled 407 adults at 61 sites in 11 countries and randomly assigned them in a 2-to-1 ratio to semaglutide 2.4 milligrams or placebo, alongside diet and physical-activity counseling. Participants had a body-mass index of at least 30 and both clinical and radiologic evidence of knee osteoarthritis with at least moderate pain. (nejm.org) By week 68, body weight fell 13.7% with semaglutide versus 3.2% with placebo, and the Western Ontario and McMaster Universities Osteoarthritis Index pain score improved by 41.7 points versus 27.5 points. Physical-function scores on the 36-Item Short Form survey rose 12.0 points with semaglutide and 6.5 points with placebo. (nejm.org) Semaglutide is a glucagon-like peptide-1 drug, or GLP-1 drug, already sold in the U.S. as Wegovy for chronic weight management at a 2.4-milligram once-weekly dose. The knee-arthritis study tested whether a drug used to lower body weight could also ease symptoms in a condition that often gets worse as weight rises. (fda.gov) (niams.nih.gov) Osteoarthritis is the most common form of arthritis, and U.S. advocacy figures put the number of adults with osteoarthritis at about 33 million. Federal health data show 21.3% of U.S. adults had diagnosed arthritis in 2024, underscoring how large the broader patient pool is. (arthritis.org) (cdc.gov) Researchers have long linked obesity to knee osteoarthritis partly because extra weight increases load on the joint. Newer work also points to metabolic and inflammatory pathways, meaning fat tissue may affect pain and joint damage in ways that are not just mechanical. (nature.com) (niams.nih.gov) That possibility showed up again in a separate 2026 Cell Metabolism study. The paper reported cartilage-protective effects in mice even when body weight was matched, and described a small randomized human pilot study in which semaglutide plus hyaluronic acid was linked to roughly a 17% increase in cartilage thickness on magnetic resonance imaging after 24 weeks, versus less than 1% in controls given hyaluronic acid alone. (cell.com) (sciencenews.org) The human cartilage finding came from a small pilot, not a large phase 3 trial, and the STEP 9 study did not test whether semaglutide slows structural damage inside the knee. In STEP 9, serious adverse events were similar in both groups, but treatment stopped more often with semaglutide, 6.7% versus 3.0%, most often because of gastrointestinal side effects. (cell.com) (nejm.org) Novo Nordisk said semaglutide is not approved in the U.S. for knee osteoarthritis, even after the October 30, 2024 publication of STEP 9 in The New England Journal of Medicine. For now, the clearest evidence is that weekly semaglutide helped people with obesity feel less knee pain and function better over 68 weeks. (novonordisk.mediaroom.com) (nejm.org)