The GLP-1 drug semaglutide can help obese people manage debilitating knee arthritis, a new trial has found.

People who received weekly injections of semaglutide — the active agent in the diabetes drug Ozempic and the weight-loss medication Wegovy — had a nearly 14% decrease in their body weight after 68 weeks, compared with 3% of people given a placebo, results showed. The trial was funded by Novo Nordisk, the drug company that makes semaglutide.

This weight loss translated into a decrease in knee pain and improved knee function among those taking semaglutide, researchers reported Oct. 30 in the New England Journal of Medicine.

"Obesity-related knee osteoarthritis is a progressive condition that can lead to pain and stiffness of the knee and impair critical daily functions such as walking or moving around,” said lead researcher Dr. Henning Bliddal, a professor of rheumatology with Copenhagen University Hospital in Denmark.

“The risk of developing the condition is more than four times higher in people with obesity,” Bliddal added in a Novo Nordisk news release.

Added weight places more stress on the knee, causing the natural cartilage that cushions the joint to wear down more quickly, experts say.

Dropping excess pounds is often recommended to treat knee arthritis, but it can be tough to achieve through diet and exercise alone, Bliddal noted.

For this study, researchers recruited 407 adults with obesity who also had been diagnosed with knee arthritis based on X-rays and pain scores. The patients had an average BMI of 40, which indicates severe obesity, and an average age of 56.

Two-thirds of the patients were randomly assigned to receive semaglutide, while the remaining third got a placebo. Both groups also received counseling on exercise and diet.

After 68 weeks, knee pain scores among people taking semaglutide fell by about 42 points on a 100-point pain scale, compared with a 28-point reduction among people on placebo, results show.

“The magnitude of the improvement is of a scope we haven’t seen before with a drug,” Dr. Bob Carter, deputy director of the National Institute of Arthritis and Musculoskeletal and Skin Diseases, told the New York Times. “They had an almost 50% reduction in their knee pain. That’s huge.”

Semaglutide patients also had nearly twice the improvement in physical function scores, 12 points versus 6.5 points for those talking placebo, the study says.

These results show that semaglutide could be a reasonable alternative to knee replacement surgery for people with obesity and worsening knee arthritis, Carter said.

“The good news is that surgery works for most people,” Dr. Carter said. “The bad news is that it is hugely expensive. We desperately need an effective way to treat knee pain.”