The study results are from the first head-to-head trial comparing raloxifene with once-weekly alendronate and were presented at the 51st Annual Meeting of the American College of Obstetricians and Gynecologists (ACOG) by Risa Kagan, M.D., co-medical director, FORE-Foundation for Osteoporosis Research and Education, Oakland, CA.

FOSAMAX is a prescription medicine from Merck & Co., Inc. and is available in a once-weekly dosing regimen for the treatment (70 mg) and prevention (35 mg) of postmenopausal osteoporosis. FOSAMAX is also available in once daily dosing for the treatment (10 mg) and prevention (5 mg) of postmenopausal osteoporosis.

The standard dosing regimen for FOSAMAX in the United States includes swallowing the tablet with six to eight ounces of plain water the first thing upon arising for the day and at least 30 minutes before the first food, beverage or medication of the day. After swallowing FOSAMAX, patients should not lie down for at least 30 minutes and not until after consuming their first food of the day.

FOSAMAX also significantly increased BMD at the hip (secondary endpoint) to a greater degree than Evista. Total hip BMD increased 2.0 percent for patients taking FOSAMAX versus 1.0 percent for patients on Evista at 12 months; p<0.001. Bone mineral density at the hip trochanter, a specific region of the hip, significantly increased 3.2 percent for patients treated with FOSAMAX versus 1.8 percent for patients on Evista at 12 months; p <0.001.

Significant increases in BMD with FOSAMAX at the lumbar spine and total hip were also seen at the six month data point. FOSAMAX increased BMD at the lumbar spine 3.1 percent compared to 1.7 percent for Evista at six months; p<0.001. Total hip BMD increased 1.3 percent for patients taking FOSAMAX versus 0.6 percent for patients on Evista at six months; p <0.013.

The percentage of patients either maintaining or increasing bone mineral density at the lumbar spine was 94% for FOSAMAX compared to 75% for Evista at 12 months. Also, there were greater reductions in bone turnover (the rate at which bone is lost and replaced) markers at six and 12 months with FOSAMAX than with Evista.

Preliminary safety data showed that discontinuations due to clinical adverse events were similar between the two treatment groups.

Study design
In this double-blind, randomized, one year study across 52 sites in the U.S., 456 women with osteoporosis received either FOSAMAX 70 mg once-weekly (N=223) or Evista 60 mg once-daily (N=233) and, in addition, calcium 500 mg and vitamin D 400 mg daily. All patients in the study had osteoporosis as defined by a BMD score of 2.0 standard deviations or greater below young normal mean bone mass for either the lumbar spine or total hip. BMD was measured in both groups at enrollment and again at six and 12 months of treatment. All BMD measures were validated by a quality assurance center and laboratory tests were performed by a central testing facility.

All patients were at least 40 years of age or older and at least six months postmenopausal, except for patients who were menopausal due to surgical removal of the ovaries, which required that they be at least 25 years of age. Patients with a history of breast or uterine cancer, or who used medicines that included a bisphosphonate, a parathyroid hormone (PTH), estrogen, estrogen analogues, or selective estrogen receptor modulators (SERMS) within one year of the study were excluded from enrollment.

The primary efficacy analysis was intention-to-treat. In addition to the primary endpoint (mean percentage change of BMD at the lumbar spine after one-year), the secondary endpoints included mean percentage change in BMD in the total hip and the hip trochanter. Other secondary endpoints included mean percent change in bone turnover markers [indicators of the rate of bone resorption (breakdown) and formation] and percentage of patients who maintained or increased BMD at the lumbar spine.

Some patients may develop severe digestive reactions including irritation, inflammation or ulceration of the esophagus. The risk of severe esophageal experiences appears to be greater in patients who fail to follow dosing instructions (see prescribing information for more details). Patients who experience heartburn, difficulty or pain when swallowing or chest pain should stop taking the drug and consult their doctor.

The most commonly reported side effects with FOSAMAX have been abdominal pain, musculoskeletal pain, indigestion, regurgitation and nausea.

FOSAMAX is a medicine from Merck & Co., Inc.
Introduced in 1995 for the treatment of postmenopausal osteoporosis, FOSAMAX is also approved for: the treatment of Paget's disease of bone (40 mg once daily); the prevention of osteoporosis in postmenopausal women at risk of osteoporosis (5 mg once daily, 35 mg once weekly); the treatment of postmenopausal osteoporosis and the reduction in the incidence of hip and spine fractures in postmenopausal women who have osteoporosis (10 mg once daily, 70 mg once weekly).

In addition, FOSAMAX is approved for the treatment of glucocorticoid-induced osteoporosis in men and women receiving glucocorticoids in a daily dosage equivalent to 7.5 mg or greater of prednisone and who have low bone mineral density (5 mg once daily, except for postmenopausal women not receiving estrogen, for whom the recommended dosage is 10 mg once daily); and for the treatment to increase bone mass in men with osteoporosis (10 mg once daily; alternatively, 70 mg once weekly may be considered).