Role of glucosamine in the treatment for osteoarthritis.

Over the last 20 years, several studies have investigated the ability of glucosamine sulfate to improve the symptoms (pain and function) and to delay the structural progression of osteoarthritis. There is now a large, convergent body of evidence that glucosamine sulfate, given at a daily oral dose of 1,500 mg, is able to significantly reduce the symptoms of osteoarthritis in the lower limbs. This dose of glucosamine sulfate has also been shown, in two independent studies, to prevent the joint space narrowing observed at the femorotibial compartment in patients with mild-to-moderate knee osteoarthritis. This effect also translated into a 50 % reduction in the incidence of osteoarthritis-related surgery of the lower limbs during a 5-year period following the withdrawal of the treatment. Some discrepancies have been described between the results of studies performed with a patent-protected formulation of glucosamine sulfate distributed as a drug and those having used glucosamine preparations purchased from global suppliers, packaged, and sold over-the-counter as nutritional supplements.

The treatment of severe postmenopausal osteoporosis : a review of current and emerging therapeutic options.

Several chemical entities have shown their ability to reduce axial and/or appendicular fractures in patients with osteoporosis. Since patients who have experienced a previous fracture are at high risk for subsequent vertebral or hip fracture, it is of prime importance to treat such patients with medications that have unequivocally demonstrated their ability to reduce fracture rates in patients with prevalent fractures. Results obtained with calcium and vitamin D, in this particular population, are not fully satisfactory and these medications are probably better used in conjunction with other therapeutic regimens. Bisphosphonates have shown their ability to reduce vertebral (alendronate, risedronate, ibandronate) and non-vertebral (alendronate, risedronate) fractures in patients with established osteoporosis. Raloxifene has also shown similar properties, notwithstanding its effect on non-vertebral fractures, which has only been derived from a post hoc analysis limited to patients with prevalent severe vertebral fractures at baseline. This compound also has interesting non-skeletal benefits, including effects on the breast and heart. Teriparatide, a bone-forming agent, promptly reduces the rate of vertebral and all non-vertebral fractures, without significant adverse effects. Strontium ranelate, the first agent shown to concomitantly decrease bone resorption and stimulate bone formation, has also shown its ability to reduce rates of vertebral and non-vertebral fractures in patients with established osteoporosis. It significantly reduces hip fractures in elderly individuals at high risk for such events. Its safety profile is also excellent.

Strontium ranelate: a new treatment for postmenopausal osteoporosis with a dual mode of action.

In vitro, strontium ranelate increases collagen and noncollagen protein synthesis by mature osteoblast-enriched cells. Its effects on bone formation were confirmed as the drug enhanced preosteoblastic cell replication. In the isolated osteoclast, preincubation of bone slices with strontium ranelate-induced dose-dependent inhibition of the bone-resorbing activity of treated rat osteoclast. Strontium ranelate dose-dependently inhibited preosteoclast differentiation. Its effect in postmenopausal women with established osteoporosis was assessed during an international, prospective, double-blind, randomized, placebo-controlled phase 3 program comparing strontium ranelate 2 g daily with placebo. The 3-year analysis of the phase 3 study, Spinal Osteoporosis Therapeutic Intervention, evaluating the effect of strontium ranelate 2 g/day on vertebral fracture rates, revealed a significant 41% reduction in the relative risk of patients experiencing new vertebral fracture with strontium ranelate over 3 years. A second phase 3 study showed a significant reduction in the relative risk of experiencing a nonvertebral fracture in the group treated with strontium ranelate over 3 years. These results show that strontium ranelate is a new, effective, and safe treatment for vertebral and hip osteoporosis, with a unique mode of action, increasing bone formation and decreasing bone resorption leading to a rebalance of bone turnover in favor of bone formation.

Strontium ranelate (Fujisawa/Servier).

Strontium ranelate (PROTELOS), a divalent strontium salt, has been developed and launched by Servier for the treatment of osteoporosis. Fujisawa Pharmaceutical is developing the drug in Japan; in November 2004, phase II Japanese trials were ongoing.