SAN DIEGO, Calif. – High doses of risedronate (Actonel®) may protect against subchondral bone loss in knee osteoarthritis (OA) patients with progressive
joint-space narrowing (JSN), according to a new study1 presented here Tuesday at the 69th Annual Meeting of the American College of Rheumatology.

In the 2-year trial, patients with progressive JSN who took risedronate 15 mg/day halted trabecular bone loss, and those participants who took a 50 mg/week dose actually added bone back to the joint, the study showed.

"Higher doses of risedronate in postmenopausal women may delay joint destruction and the need for joint replacement surgery in patients with severe knee OA," says lead researcher J. Christopher Buckland-Wright, MD, a professor of radiological anatomy at Kings' College London in the UK.

Previous research has shown that bone under the cartilage is osteoporotic in these patients, due to loss of the vertical trabecular bars. This loss leads to the breakdown of the joint and a potential need for knee arthroplasty. Risedronate, however, can increase trabecular thickness.

Patients received either risedronate 5 mg/day, 15 mg/day, 50 mg/week, or placebo. Each arm comprised 300 patients. Researchers used standard x-rays and a novel computational technique to assess changes in trabecular bone structure.

While participants in the high-dose groups were protected against subchondral bone loss, the degree of bone loss was substantially greater in the knees of patients with progressive JSN in both the placebo and 5 mg groups (P <.05) for vertical and horizontal trabeculae, the study showed.

Search for DMOAD continues

"Most OA drugs treat pain, and attempts to protect the joint have been less than stellar so far," Dr. Buckland-Wright points out.

For example, doxycycline, which is thought to have disease-modifying properties in knee OA, had no effect on joint space narrowing or pain in disease-free knees in a recent study.2

Ideally, a disease-modifying osteoarthritis drug (DMOAD) would not only be a structural modifier, but also provide symptom relief, according to Dr. Buckland-Wright. "That might almost be impossible to achieve," he continues, "but if one has a drug to maintain the joint, in the long-term, it may have a benefit on symptoms."

"There is no good data on a DMOAD that prevents the progression of the disease," Elizabeth Karlson, MD, assistant professor of medicine at Brigham and Women's Hospital in Boston, Massachusetts, tells CIAOMed. However, she continues, "the risedronate data are encouraging and should be explored and tested further."

References

  1. Buckland-Wright JC, Messent EA,  Cline GA, et al. Risedronate protects against subchondral bone loss in OA knee patients with progressive joint space narrowing. Presented at: 69th Annual Meeting of American College of Rheumatology; November 12–17, 2005; San Diego, Calif. Abstract 1204.
  2. Brandt KD, Mazzuca SA, Katz BP, et al. Effects of doxycycline
    on progression of osteoarthritis: results of a randomized, placebo-controlled, double-blind trial. Arthritis     Rheum. 2005;52:2015–2025.