New Treatment for Osteoporosis Is Close at Hand : Health: Drug will work in different way from existing medications. It is on fast track for FDA approval.

A new treatment for osteoporosis, the bone-thinning disease that affects primarily women after menopause, is about to become available.

It’s a drug that works in a different way from existing medications to prevent loss of bone mass. Its name is alendronate sodium, and it will be marketed under the trade name of Fosamax.

Alendronate is a member of a family of medicines called biphosphonates that are being developed for prevention and treatment of osteoporosis. The drugs in use today are hormones, either the female sex hormone estrogen or the calcium-related hormone calcitonin, along with calcium supplements.

Osteoporosis occurs after menopause because there is a change in the balance between the rate at which bone is broken down, or resorbed, and the rate at which new bone is created. Bone resorption increases after menopause, so bones start getting thinner.

There usually are no early symptoms of bone loss. Many cases of osteoporosis are diagnosed only after a fracture occurs. It’s estimated that there are 1.5 million osteoporosis-related fractures every year, including 250,000 hip fractures.

Estrogen replacement therapy is widely used but controversial, because of fears that it may increase the risk of some cancers.

Biphosphonates help prevent fractures by inhibiting bone resorption. Several studies have shown that alendronate sodium can reduce the number of postmenopausal fractures significantly. The most common side effect seen in those studies has been mild gastrointestinal upset.

Because of the studies, the drug was put on the fast track for approval by the Food and Drug Administration, and it’s expected to appear shortly.

Osteoporosis affects an estimated 25 million American women, and some men as well. Treatment of hip fractures alone is estimated to cost $10 billion a year, and the cost will go up as the American population gets older.