Protelos®: First Osteoporosis Treatment To Show Long-Term, Sustained Efficacy And Quality Of Life Improvement

Main Category: Bones / Orthopedics
Article Date: 08 May 2007 - 12:00 PDT

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New, long term data presented at the 34th European Symposium on Calcified Tissues (ECTS) this week underscore the unmatchable, long-term efficacy and quality of life improvement offered by the anti-osteoporotic treatment, Protelos® (strontium ranelate). These data also provide evidence to show that Protelos has clinical benefit in a broad range of osteoporotic patients, irrespective of their level of bone turnover and severity of their disease.

Protelos is a new anti-osteoporosis treatment with a unique mode of action both increasing bone formation and decreasing bone resorption. For the first time, new data have shown sustained, five year efficacy against vertebral and non-vertebral fractures, including hip fractures.1 Protelos is also the first treatment to show an improvement in the quality of life of patients with vertebral postmenopausal osteoporosis over four years.2

Five year efficacy1

Five year data on the long term antifracture efficacy of Protelos from the TROPOS (TReatment Of Peripheral OSteoporosis) study show that, uniquely for an anti-osteoporotic treatment, Protelos provides sustained five year efficacy against vertebral, non vertebral and hip fractures. The phase III study, run across 75 European and Australian centres involved over 5,000 women with postmenopausal osteoporosis with mean age of 76 given either 2g daily of Protelos or placebo for five years. All patients also received calcium and vitamin D supplements according to their needs.

The five year results revealed a 24% reduction in vertebral fracture (p<0.001) and 15% reduction in non-vertebral fracture (p<0.03) in the intent-to-treat population. Additionally, there was a 43% reduction of the risk of hip fracture in women who had a higher risk of fractures (74 years and older with a low lumbar and femoral neck bone mineral density T-score, p<0.036).

Quality of life2

Vertebral fractures can lead to a significant downturn in patients' health-related quality of life (HRQoL).

The SOTI (Spinal Osteoporosis Therapeutic Intervention) study, a double-blind placebo-controlled study carried out in 1649 postmenopausal osteoporotic women, measured the impact of Protelos on HRQoL for four years. In this study, women were given 2g daily of Protelos or placebo.

At the end of the four year period, the Protelos group achieved significantly more positive QoL scores than the placebo group. This group also demonstrated improved QoL compared to a deterioration of QoL in the placebo group. Also, the number of patients who did not suffer from back pain was 28% higher in patients on Protelos compared with those on placebo (p=0.005). The women were assessed every six months, using both a general QoL questionnaire and QUALIOST®, a specific vertebral osteoporosis questionnaire.

"These robust results show Protelos' sustained QoL benefits, confirming that the treatment maintains its QoL benefits for patients with vertebral postmenopausal osteoporosis over a four year period. It is the first anti-osteoporotic treatment to show a QoL benefit for this patient group", points out SOTI investigator Professor C Roux from Hôpital Cochin, Paris.

Efficacy across broad range of patients3

Bone turnover marker (BTM) levels may influence the antifracture efficacy of anti-osteoporotic treatments and are therefore taken into account when deciding to commence treatment. To measure the link between BTM levels and the efficacy of Protelos, results from both the SOTI and TROPOS trials were examined.

After three years of treatment, the risk of new vertebral fractures was significantly lower in the group taking Protelos than those receiving placebo, regardless of their BTM levels.

"We found that the efficacy of Protelos to significantly reduce the incidence of vertebral fractures is largely independent of pre-treatment bone turnover", said study author Professor J Collette from the Liège University Hospital, Belgium. "This suggests that Protelos offers clinical benefits to osteoporotic women across a wide range of metabolic states and disease severity."

Unique dual mode of action 4,5

Two further studies presented at the ECTS meeting provide insight into Protelos' unique mechanism of action. These studies show that that the new agent promotes either the differentiation of osteocytes, and/or osteocyte survival which can, at least in part, explain its ability in vivo to correct the balance between bone resorption and formation in osteoporosis and that Protelos increases bone formation, while simultaneously increasing the expression of osteoprotegerin, a protein that protects against bone loss, reducing bone resorption.

Protelos 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 registered in 77 countries worldwide and launched in 44 countries, including France, Germany, the UK, Spain, and Italy.

References:

1. JY Reginster, K Brixen, C Cormier, J Cannata. Strontium ranelate demonstrates vertebral and non-vertebral anti fracture efficacy including hip fractures over 5 years in post menopausal osteoporotic women. Poster presentation ECTS 2007.
2. P. Marquis, C Roux, M Diaz-Curiel, C Cormier G Isaia, J Badurski, JD Wark. Long-term beneficial effects of strontium ranelate on the quality of life in patients with vertebral osteoporosis (SOTI study). Poster presentation ECTS 2007.
3. J.Collette. Strontium ranelate decreases vertebral fracture risk whatever the level of pretreatment bone turnover markers. Oral presentation ECTS 2007.
4. TC Brennan MS Rybchyn, P Halbout, AD Conigrave, RS Mason, Strontium ranelate effects in human osteoblasts support its uncoupling effect on bone formation and bone resorption. Poster presentation ECTS 2007.

GJ Atkins, KJ Welldon, DM Findlay. Strontium ranelate promotes an osteocyte-like phenotype from human primary osteoblasts ex vivo

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