Protelos(R) in Treatment of Osteoporosis: Unique Dual Mode of Action Explained and Clinical Benefits on Bone Quality Highlighted

Toronto, Canada (ots/PRNewswire) -

- The Increase of OPG Expression Explains the Uncoupling Effect of
Protelos(R) on Bone Metabolism

Exciting new data presented at the World Congress on Osteoporosis
further the understanding of the unique dual mode of action of the
anti-osteoporotic agent Protelos(R) (strontium ranelate)(1), which
makes it totally different from the other existing treatments
available.

Results from a study on osteoblasts (cells responsible for
creating the bone matrix) confirm that Protelos(R) stimulates bone
formation and also decreases bone resorption. Protelos(R) was found
to stimulate the expression of osteoprotegerin (OPG), a protein that
inhibits osteoclast (cells responsible for resorbing bone) formation
and activity. OPG is produced naturally in osteoblasts.

Protelos(R) reduces both vertebral and hip fractures in
postmenopausal women and is an effective treatment for osteoporosis.
Previous studies have shown that Protelos(R) increases the bone
formation and decreases bone resorption and thus rebalances bone
turnover in favor of bone formation. The study has, for the first
time, demonstrated the uncoupling effect of Protelos(R) at the
cellular level. By acting directly on osteoblasts, Protelos(R)
increases OPG mRNA expression leading to a decrease in bone
resorption through a "decoupling" between osteoclasts and
osteoblasts. These data therefore explain for the first time
Protelos(R)' unique mode of action at a cellular level.

Effect of Protelos(R) on osteoblasts

The in vitro study evaluated the effect of Protelos(R) on the
proliferation of osteoblasts and OPG expression in human
preosteoblastic cells. Protelos(R) significantly and dose-dependently
stimulates the proliferation of osteoblasts after treatment. In
addition, Protelos(R) significantly and dose dependently increases
the expression of OPG mRNA after treatment, thereby inhibiting bone
resorption.

Effect of Protelos(R) on bone quality

According to new three-dimensional (3D) bone biopsy data from
Yebin Jiang, MD, PhD and his colleagues from the University of
California, San Francisco, USA, Protelos(R) has beneficial effects on
the 3D bone microstructure thereby improving bone mechanical
competence and bone quality(2).

"Bone quality in terms of fracture resistance is a function of the
bone's apparent density and three-dimension distribution," points out
Dr Jiang. "The action of Protelos(R) on 3D trabecular and cortical
microstructure helps explain why Protelos(R) treatment reduces the
risk of vertebral and hip fractures."

Dr Jiang and colleagues studied transiliac bone biopsies from 41
postmenopausal women participating in the SOTI (Spinal Osteoporosis
Therapeutic Intervention)(3) and TROPOS (Treatment Of Peripheral
Osteoporosis)(4) studies. The biopsies were from women treated with
either Protelos(R) 2g/day (n=20) or placebo (n=21). Compared to
placebo, Protelos(R) treatment significantly stimulates 3D trabecular
and cortical bone formation leading to an improvement of bone
microstructure.

Protelos(R) has sustained efficacy against both vertebral and hip
fractures in postmenopausal osteoporotic women.(5) In addition, it is
well tolerated and easy to use for patients.(6)

Protelos(R) is licensed in Europe for the treatment of
postmenopausal osteoporosis to reduce the risk of vertebral and hip
fractures in patients with or without a previous history of
fractures. It is now available in 57 countries worldwide, including
France, Germany, the UK, Spain, and Italy.

References:
1. Brennan Tc et al. Calcif Tissue Int. 2006;78(suppl 1):S129 (P356).
2. Jiang Yebin, Oral communication, World Congress on Osteoporosis 2006,
Toronto, Canada.
3. Meunier PJ, Roux C, Seeman E, et al. N Engl J Med. 2004;350:459-468.
4. Reginster JY, Seeman E, De Vernejoul MC, et al. J Clin Endocrinol
Metab. 2005;90:2816-2822.
5. Reginster JY. Osteoporos Int. 2006;17:S11-S12 (OC31).
6. Protelos(R) European Summary of Product Characteristics.

ots Originaltext: Servier International
Im Internet recherchierbar: http://www.presseportal.de

Contact:
For further information or to arrange an interview with Dr Jiang,
please contact: Moira Gitsham, tel +33-5-46-00-08-20, mobile:
+33-6-20-74-01-92, email: moira.gitsham@toniclc.com; Lola Bhadmus,
tel +44(0)207-798-9900, email: lola.bhadmus@toniclc.com