Danish drugmaker Nycomed and NPS Pharmaceuticals of the USA have won European approval for a new injectable treatment for osteoporosis based on parathyroid hormone.

Preotact (parathyroid hormone [rDNA origin] for injection), known as Preos in the USA, recently received an "approvable letter" from the US Food and Drug Administration as an osteoporosis treatment. The agency expressed concerns regarding hypercalcaemia associated with the proposed daily dose of the drug, and requested additional reliability data relating to the injection device used in its administration. NPS says it has requested a meeting with the FDA to address these issues.

The European Medicines Agency (EMEA) has approved Preotact for the treatment of post-menopausal women with osteoporosis at risk of fractures. NPS, which licensed the EU development and marketing rights to Preotact to Nycomed in 2004, said that approval is a significant event for both firms, adding that it will roll out the product in Europe later in the year.

A pivotal Phase III study of Preotact, known as TOP, showed that the product caused a statistically significant reduction in the risk of new vertebral fractures in women with and without pre-existing osteoporosis-related fractures.

Preotact will compete with Eli Lilly’s Forsteo (teriparatide), a PTH fragment that was approved as a treatment for post-menopausal osteoporosis in Europe in 2003. Like Preos, Forsteo (sold as Forteo in the USA) is given as a once-daily injection, but was delayed on its way to market after being linked to an increased risk of osteosarcoma in rats.

This side effect has not been seen in humans, and although Lilly’s drug carries a label warning of the risk, Forteo sales reached $127 million in the first quarter of 2006, a 90% increase year-on-year.

By 2010, the market for osteoporosis drugs is expected to grow to around $10 billion, although the market is expected to remain dominated by orally-active drugs such as the bisphosphonates, with injectables such as Preotact and Forteo – which tend to be more expensive - reserved mainly for severe cases of the disease.