Efficacy and Safety of Strontium Ranelate in the Treatment of Knee Osteoarthritis: Results of a Double-Blind, Randomised Placebo-Controlled Trial
Reginster JY, Badurski J, Bellamy N, et al
Ann Rheum Dis. 2013;72:179-186
Osteoarthritis
Osteoarthritis is the most common form of arthritis and results in substantial disability and healthcare costs. Many agents (eg, nonsteroidal anti-inflammatory drugs) can improve the symptoms of osteoarthritis, and joint replacement is also successful in improving symptoms. To date, however, although several systemic therapies have been tried as disease-modifying osteoarthritis drugs, none has demonstrated dramatic success.
Because of its similarity in structure to calcium, strontium can be taken up into the bone. When coupled as a salt to ranelic acid, strontium can increase osteoblast-mediated bone formation and inhibit osteoclast-mediated bone resorption. Because of these effects, strontium has been used to treat osteoporosis. Some studies also suggest that strontium ranelate can stimulate formation of cartilage matrix and therefore may be beneficial in osteoarthritis.
Study Summary
In this randomized, double-blind, placebo-controlled trial, called SEKOIA, Reginster and colleagues used strontium ranelate at either 1 or 2 g daily compared with placebo in 1371 patients with grade 2 or 3 knee osteoarthritis, as defined by Kellgren and Lawrence, with a joint space width of 2.5-5 mm. Patients were followed for 3 years, and outcomes included radiographic changes in joint space width, overall health related to osteoarthritis as measured by the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score, and pain as measured on a visual analog scale.
Treatment with strontium ranelate at a daily dose of 1 or 2 g was associated with a statistically smaller reduction in joint space width on plain radiography. Treatment with the 2-g/day dose was also associated with improved health status related to osteoarthritis, as measured by the overall WOMAC score (P = .045) and a WOMAC subscore of pain (P = .028). The WOMAC subscore for physical function and knee pain as measured by the visual analog scale trended toward improvement in patients treated with the 2-g/day dose but did not reach statistical significance.
No significant differences between groups were found in laboratory-based biomarkers, such as urinary C-telopeptide of type II procollagen, a marker of cartilage turnover. In addition, the groups did not differ significantly in safety-related outcomes, especially allergic reactions or thrombosis, that are known possible complications of strontium treatment.
Reginster and colleagues concluded that treatment with strontium ranelate at daily doses of 1 or 2 g is associated with a significant reduction in progression of radiographic joint space width, and at 2 g/day with an effect on overall health associated with osteoarthritis.