'Silent killer' osteoporosis quietly on the increase
(Published 8 January 2005)

Osteoporosis currently affects 30 million people (predominantly women) worldwide and if left untreated, can be fatal. Historically hormone replacement therapy (HRT) has been used to help prevent the bone loss that leads to osteoporosis. However recent negative study results have lead to a rapid decline in its use, which may lead to a significant increase in the prevalence of osteoporosis.

A Women's Health Initiative (WHI) study found that while HRT did reduce the risk of fractures due to osteoporosis, it also increased the risk of heart attack, stroke, breast cancer and blood clots. Because of these findings there has been a dramatic reduction in the use of HRT, which could leave thousands of women unprotected from the increased risks of bone loss and fractures associated with menopause.

Osteoporosis - often dubbed the 'silent killer' - is a disease in which bones become fragile and more likely to break if not prevented or if left untreated. Osteoporosis can progress painlessly until a bone breaks, typically in the hip, spine or wrist. Any bone can be affected, but of particular concern are fractures of the hip and spine. A hip fracture almost always requires hospitalization and major surgery and it can impair a person's ability to walk unassisted and may cause prolonged or permanent disability or even death.

Spinal or vertebral fractures also have serious consequences including loss of height, severe back pain and deformity. Needless to say bone fractures as a result of osteoporosis place huge financial pressure on national health services.

In the US alone in 2001, the estimated national direct expenditures (hospitals and nursing homes) for osteopathic and associated fractures was $17billion ($47 million per day), and the cost is rising.

Preventable with good defense

Osteoporosis is largely preventable for most people; the best defense against it is building strong bones, particularly before the age of 30. Coupled with the general bone loss that occurs after the age of 35, the lowered estrogen levels in women after the menopause may cause loss of bone mass at a rate that is two to four times faster than that seen before the menopause, leading to osteoporosis, or porous bones.

While 20% of osteoporosis cases are in men, it is important that women especially take recognized steps to preventing osteoporosis like getting enough calcium and vitamin D, engaging in regular weight bearing exercise and avoiding smoking and excessive drinking.

Increased awareness of the risks involved and better screening programs would also allow potential sufferers to be identified sooner and thus receive treatment to prevent the onset of osteoporosis.

While the results of the WHI lead to $850 million being wiped off the market value of HRT in 2003, some opinion leaders spoken to by Datamonitor suggest there could be an even greater price to pay:

"I think we are going to see an increase in osteoporosis and fractures from all the women that have stopped taking their HRT, and then the pendulum will swing back," commented one US opinion leader

Despite some reservations, the osteoporosis market is forecast to grow from $8.3 billion in 2003 to be worth $14.7 billion by 2014, according to Datamonitor research. The growth of the market is expected to be driven by uplift after the WHI and new product launches to 2009. Unfortunately it is difficult to get an accurate gauge on the potential increase in prevalence due to the lack of national screening programs and thus lack of national data available.

Fosamax leads the way, but for how long?

The current leading drug for osteoporosis is Merck & Co's Fosamax, however its market share of 35% is expected to decline to 8.5% by 2014 as a result of patent expiry and competition from cheaper generics. Fosamax belongs to the bisphosphonates class of drug, which are considered the gold standard in osteoporosis treatment, along with Aventis/P&G's Actonel which generated sales of $940 million in 2003. Datamonitor predicts Actonel will become a blockbuster ($1 billion in sales) by year-end 2004.

There are currently two bisphosphonates in the late-stage development pipeline for osteoporosis, Roche/GSK's Boniva and Novartis's Zometa: Boniva is expected to hit the US market in 2005 and the European market in 2006. Datamonitor predicts that Boniva will take market share from both Fosamax and Actonel because it represents a new treatment option for those patients not responding to currently available drugs, as well as offering a more convenient regimen to improve compliance and therefore disease management.

Zometa is currently in Phase III trials and Datamonitor assumes that the earliest launch of this indication will be in the US by 2008, where the product will take share from Fosamax and its generics, as well as Actonel and other drugs at a rate of 10% over three years. The annual IV dosing regimen will meet a need in the market for greater compliance with therapy and have the potential to target a niche, but often neglected, hospital population at high risk of bone loss.

While these treatments help to treat osteoporosis following diagnosis, they can also prevent the condition in those at risk. One of the greatest unmet needs in this area remains primary prevention and the need for adequate testing programs to identify those at risk, initiate treatment and prevent costly fractures later in life.

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