As the knee’s natural cushioning — the cartilage — wanes, inflammation and pain rise, and people can’t get around as well.

Building knee cartilage has been a dream of researchers, and now several methods are under study. None has yet shown it can prevent or cure osteoarthritis, and all are in early phases, caution the scientists who presented their findings at the recent annual meeting of the American College of Rheumatology in San Diego, CA.

Stopping Excess Bone Breakdown

A treatment known as MIV-711 targets an enzyme called cathepsin K that is thought to play a role in the destruction of cartilage and the breakdown of too much bone.

In adults, bones are constantly being broken down and built up or replaced to maintain a healthy skeleton.  “This [treatment] stops the increased breakdown of bone that happens in OA,” says researcher Philip Conaghan, MD, a professor of musculoskeletal medicine at the University of Leeds in Great Britain. “It inhibits the cathepsin K.” The bone changes happen before the cartilage loss does, he says.

In the study, researchers assigned 244 men and women who have knee arthritis to get one of two oral doses of the treatment or a placebo pill for up to 28 days. The participants’ average age was 62, and many were overweight or  obese.

The researchers did MRIs at the beginning of the study and at week 26 to find changes around the bone, which reflect cartilage change. They found 65% less bone disease progression in the treated groups, regardless of dose, Conaghan says.

But they found no less pain. “It did not help symptoms,” he says.