Bone Drug Might Help Arthritic Knees, Study Says

But more testing is needed before U.S. approves it, one expert says

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By
HealthDay Reporter

SATURDAY, Nov. 10, 2012 (HealthDay News) -- A drug marketed for osteoporosis may slow the progression of knee osteoarthritis, a new study suggests.

The drug, called strontium ranelate (brand name Protelos), may also relieve knee pain and lessen damage to the joint, perhaps preventing knee-replacement surgery in some cases, researchers said.

"Osteoarthritis and osteoporosis are not a normal process of aging -- drugs can help," said lead researcher Dr. Jean-Yves Reginster, chairman of the department of public health sciences at the University of Liege, in Belgium.

"A drug currently marketed in most countries outside the U.S. for the management of osteoporosis also treats symptoms and structure-progression in osteoarthritis," he added. "It seems this type of drug could take care of both bone and joint diseases in the elderly."

The results of the study were scheduled for presentation Saturday at the annual meeting of the American College of Rheumatology in Washington, D.C.

For the study, Reginster's team randomly assigned almost 1,700 patients suffering from osteoarthritis to one of three groups. Two groups received different doses of the drug on a daily basis, while the third group got a placebo.

To evaluate the drug's effectiveness, patients underwent a yearly digital X-ray and the researchers used other tests to measure spaces in the knee joint to see the loss of cartilage. In addition, patients were asked about pain, stiffness and their ability to use the knee.

Over three years, the researchers found that patients taking strontium ranelate had less knee damage compared with those taking the placebo. Moreover, patients taking the drug reported less knee pain and improved function, they noted.

The drug was well-tolerated and no significant side effects were noted between those taking the drug and those receiving a placebo.

Strontium ranelate is approved in 102 countries for managing osteoporosis, the bone-thinning disease, but not in the United States. Britain's Medicines and Healthcare Products Regulatory Agency has reported that some serious side effects, including a rare skin rash, have been associated with the use of strontium ranelate.

Knee osteoarthritis results from cartilage breakdown in the knee joint. Obesity, age, prior injury to the knee, extreme stress to the joints and family history all increase the risk for the condition.

According to the U.S. National Center for Health Statistics, almost one-quarter of U.S. adults have arthritis. By age 85, half will have symptomatic knee arthritis, the researchers said. No drug is currently approved in the United States to delay progression of arthritis.

In earlier studies, strontium ranelate was shown to prevent back and hip fractures. In other research, the drug stimulated bone mass by slowing the breakdown of bone and stimulating new bone growth, the researchers noted.

One expert welcomed the new study.

"This is very promising," said Dr. Diane Horowitz, an attending physician in the division of rheumatology at North Shore-LIJ Health System in Manhasset, N.Y. "It could open new avenues for treatment."

Horowitz added, however, that more testing needs to be done before the drug is approved in the United States.

Data and conclusions presented at medical meetings typically are considered preliminary until published in a peer-reviewed medical journal.

More information

For more information on osteoarthritis, visit the U.S. National Library of Medicine.

SOURCES: Jean-Yves Reginster, M.D., Ph.D., chairman, department of public health sciences, University of Liege, Belgium; Diane Horowitz, M.D., attending physician, Division of Rheumatology, North Shore-LIJ Health System, Manhasset, N.Y.; Nov. 10, 2012, American College of Rheumatology annual meeting, Washington, D.C.

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