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Strontium Ranelate Research And Impact On Osteoporosis Treatment

Research indicates that prescription formula strontium ranelate can improve bone density by 8-14%. There is no evidence though that it improves bone density more effectively than strontium citrate, which is available in health food stores.

One pharmaceutical company claims that it could fundamentally change the treatment paradigm of patients with osteoporosis.

Research indicates that strontium ranelate can improve bone density by 8-14%.

But there is no evidence that prescription formulas improve bone density more effectively than strontium citrate, which is available in health food stores.

Puritan's Pride sells strontium at the most attractive price we could find on the internet... as well as the calcium, magnesium and vitamin D to support it.

As early research on strontium indicates that it is the mineral itself which provides the bone building benefits (rather than the salt that binds it), there is significant controversy over whether prescription strontium provides superior benefits to that provided by strontium supplements within an osteoporosis prevention program.

This is an important question both to individuals and taxpayers who will pay for a treatment program that could be in demand by 44 million people in the United States and 1.4 million people in Canada.

Early Research On Strontium

Research on the role of stable strontium in bone health began in the 1950's at the same time that nuclear testing was most prominent. Although research conducted by the Mayo Clinic in 1959 was promising, little follow-up was conducted for the next 30 years.

Mayo Clinic (1959)

In 1959, researchers at the Mayo Clinic investigated the effect of strontium in 32 individuals suffering from osteoporosis. Each patient received 1.7 grams of strontium lactate per day with the result that 84% of the patients reported marked relief of bone pain at the end of the study.

X-rays taken at the beginning and end of the study showed "probable" increased bone mass in 78 percent of the cases. Unfortunately, measurement of bone mass in 1959 was pretty crude, leading the researchers to qualify their interpretation of the X-rays. (Sophisticated tests such DXA and CT scanning were not available at the time of the study.)

No significant side effects were seen, even with prolonged (up to three years) administration of strontium.

(McCaslin, F.E., Jr., and Janes, J.M. The effect of strontium lactate in the treatment of osteoporosis. Proc Staff Meetings Mayo Clin, 1959, 34:329-334.)

Bone Cancer Study-McGill (1981)

In 1981, Dr. Stanley C. Skoryna of McGill University in Montreal tested the effect of 274 mg/day of strontium gluconate on patients with breast or prostate cancer that had spread to the bones. (This dose was much lower than the 600 to 700 mg/day used in later studies but strontium gluconate is absorbed more efficiently than strontium carbonate).

X-rays taken before and after strontium therapy demonstrated new mineral deposits in areas of bone that had been eroded by the cancer.

(Skoryna, S.C., 1981. Effects of oral supplementation with stable strontium. Can Med Assoc J, 125: 703-712.)

Osteoporosis Study – McGill (1985)

In 1985, Dr. Stanley C. Skoryna followed his bone cancer study with a small-scale study of three men and three women with osteoporosis using 600 to 700 mg/day of strontium carbonate.

Bone biopsies of the hip bones taken before and after six months of treatment showed a 172% increase in the rate of bone formation after strontium therapy, with no change in bone resorption.

(Marie, P.J., Skoryna, S.C., Pivon, R.J., Chabot, G., Glorieux, F.H., Stara, J.F. Histomorphometry of bone changes in stable strontium therapy. In: Trace substances in environmental health XIX, edited by D.D. Hemphill, University of Missouri, Columbia, Missouri, 1985, 193-208.)

Recent Research On Strontium Ranelate/Malonate

Interest in strontium has been rekindled by a number of studies using the strontium salt ranelic acid (strontium ranelate) in Europe and now malonate in the US.

STRATOS Trial (2002)

The STRATOS trial (strontium ranelate (SR) for treatment of osteoporosis) studied osteoporotic women using both a placebo and strontium in doses of 170, 340 or 680 mg/day for two years. The scientists evaluated lumbar and hip bone mineral density (BMD) using dual-energy X-ray absorptiometry (DXA).

The study found a significant reduction in new vertebral fractures and also a significant positive change in bone metabolism in the group that received 680 mg/day of strontium for two years.

The authors concluded that the 680 mg/day dose offered the best combination of efficacy and safety, and stated without equivocation that strontium ranelate therapy increased vertebral BMD and reduced the incidence of vertebral fractures.

(Meunier, P.J., Slosman, D.O., Delmas, P.D., Sebert, J.L., Brandi, M.L., Albanese, C., Lorenc, R., Pors-Nielsen, S., De Vernejoul, M.C., Roces, A., Reginster J.Y. Strontium ranelate: dose-dependent effects in established postmenopausal vertebral osteoporosis – a 2-year randomized placebo controlled trial. J Clin Endocrinol Metab, May 2002; 87(5):2060-6.)

STRATOS Trial (2004)

The STRATOS research team followed its first trial with a much larger study of 1,649 osteoporotic postmenopausal women over a three year period. Participants received 2 gm/day of strontium ranelate (providing 680 mg strontium) or placebo, as well as calcium and vitamin D supplements before and during the study.

In addition to suffering fewer fractures, patients in the strontium group increased lumbar bone mineral density by an average of 14.4 percent and femoral neck BMD an average of 8.3 percent.

The authors concluded that "treatment of postmenopausal osteoporosis with strontium ranelate leads to early and sustained reductions in the risk of vertebral fractures." (Meunier PJ, Roux C, Seeman E et al. (2004). "The effects of strontium ranelate on the risk of vertebral fracture in women with postmenopausal osteoporosis." New England Journal of Medicine 350: 459-468. doi:10.1056/NEJMoa022436. PMID 14749454.)

TROPOS Study (2005)

While the STRATOS studies concentrated on the lumbar spine and femoral neck, the Treatment of Peripheral Osteoporosis (TROPOS) study focused on nonvertebral fractures (hip, wrist, pelvis and sacrum, ribs and sternum, clavicle, humerus) and bone density.

The study allocated either 2 grams/day of strontium ranelate or a placebo to 5,091 postmenopausal women with osteoporosis. This was a double-blind placebo-controlled five-year study with a main statistical analysis over 3 yr of treatment.

After three years, the research found an 8.2% improvement in the femoral neck and a 9.8% improvement in the total hip bone density and concluded that strontium ranelate offers a safe and effective means of reducing the risk of fracture associated with osteoporosis.

(Reginster JY, Seeman E, De Vernejoul MC et al. (2005). "Strontium ranelate reduces the risk of nonvertebral fractures in postmenopausal women with osteoporosis: treatment of peripheral osteoporosis (TROPOS) study". J Clin Metab. 90: 2816-2822. doi:10.1210/jc.2004-1774. PMID 15728210.)

Strong Study – Phase Ii (2007)

Osteologix, Inc (San Francisco, California) announced the results of its phase II clinical trial in 2007. The trial enrolled 289 postmenopausal women with low bone mineral density (BMD) and evaluated three doses of strontium malonate (NB S101) against one dose level of strontium ranelate (Protelos®).

It reported that at 3 months, strontium malonate had significantly increased lumbar spine BMD at all doses tested, with the most significant increase of 2.66% (P <.01) for the 2 g dose. This compared favourably against Protelos (2 g) which increased lumbar spine BMD by 1.96% (P <.05).

Strontium therapy was well-tolerated and side effects were generally mild in all dose groups. There were no significant differences in the side effect profiles among the four treatment groups.

NB S101 is administered in a once-daily 1 g tablet whereas Protelos is administered as a sachet to be dissolved in water. The amount of free strontium in the Protelos product is 680 mg whereas the amount of free strontium in NB S101 is 465 mg.

Osteologix states that the bioavailability of free strontium has been increased in its product NB S101 compared with Protelos.

Prescription: Stontium Better Than Strontium Citrate?

The recent studies by pharmaceutical companies compare the effectiveness of the two patented formulas (strontium ranelate and strontium malonate) against each other but not against strontium citrate which is available as a supplement.

Earlier studies using strontium carbonate, strontium lactate, and strontium gluconate suggest that the active ingredient is strontium rather than the salt combined with the mineral and that the amount of strontium consumed is more important than the kind of salt that is used.

Supplement companies argue persuasively that there is no evidence that ranelate or malonate contributes to the effectiveness of strontium or justifies the additional cost compared to strontium citrate supplements. Additional research is needed to clarify the role of prescription strontium in a bone-building program.

While we are waiting for that research, it is interesting to read about one woman's journey towards healthy bones using strontium supplements.

Who Profits From Prescription Strontium?

Prescription strontium promises to be profitable to pharmaceutical companies.

While the added value of prescription strontium may be in question... the potential profits associated with a prescription formula are not.

In 2005, the Cambridgeshire Joint Prescribing Group prepared an advisory for its members regarding strontium ranelate relative to the prescription of bisphosphonates. The advisory provides some interesting information regarding the revenue potential of Servier's product (Protelos) in the UK.

Data provided by Servier suggested that:

  • in 2003, around 240,000 patients in the UK started or changed osteoporosis therapy, representing approximately 1,500 patients per 100,000.
  • if strontium ranelate is given to 50% (i.e. 750) of these, the maximum gross first year impact on a drug budget for a population of 400,000 would be about £250,000 ($347,546.13 USD)

The National Osteoporosis Foundation (NOF) reports that 10 million individuals in the U.S. are estimated to have osteoporosis and almost 34 million more are estimated to have low bone mass.

If a pharmaceutical company were able to capture 10% of this market, annual revenues would be approximately $430 million USD at the current price charged for Protelos in the U.K.

A complete strontium treatment program can be purchased for less than $200 USD by combining Strontium Bone Maker (strontium citrate) with the calcium, vitamin D, magnesium and vitamin K available in Puritan's Pride Bone Care.