Sanofi-Aventis has won approval in the USA and Europe to extend the indications for osteoporosis drug Actonel to include men with the disease, a group expected to increase in importance in the marketplace.

The FDA gave the go-ahead for Actonel (risedronate) in male osteoporosis, which is said to be a neglected and under-treated condition that tends to occur later in life than osteoporosis in women. Around 50% of cases are associated with advancing ages, but the remainder occur due to other causes such as oral steroid use, low testosterone and heavy alcohol use.

This follows the positive outcome in July 2006 of the European application for the additional indication of ‘treatment of osteoporosis in men at high risk of fracture’. National approvals will now follow in all twenty-five EU member states, said Sanofi in a statement.

It is also surprisingly common: about a third of hip fractures occur in men, and one in eight men older than 50 years will have an osteoporotic fracture, according to a review of the disease published in American Family Physician in 2003. Moreover, hip fractures in men are associated with a 31% mortality rate at one year after fracture, compared to 17% in women.

Prevalence data show there is now a total of 14 million men with osteoporosis and low bone density, and that figure is expected to grow to 17.3 million by 2010.

The approval is based on a two-year clinical trial involving 284 men with osteoporosis. In the trial, patients treated with once-a-week Actonel 35mg experienced statistically significant improvements in lumbar spine bone mineral density at six, 12 and 24 months.

The new indication could help differentiate Actonel in the increasingly competitive market for bisphosphonate osteoporosis drugs, which also include Merck & Co’s Fosamax (alendronate) and Roche and GlaxoSmithKline’s Bonviva (ibandronate).