Once Weekly Fosamax Equally Effective To Once Daily Regimen For Osteoporosis

Doctor's Guide
November 24, 1999

VENICE, ITALY -- November 24, 1999 -- A novel formulation of Fosamax(R) (alendronate sodium) that is administered as a once-weekly 70 mg tablet was demonstrated to be equivalent to once-daily therapy with a 10 mg tablet in a new study on the treatment of postmenopausal osteoporosis. The investigational once-weekly regimen and the currently approved once-daily regimen were demonstrated to be equally effective in increasing bone mineral density at several skeletal sites and both were generally well tolerated. The study was reported for the first time at the 6th International Symposium on Clinical Disorders of Bone and Mineral Metabolism.

"One challenge with any chronic therapy is to maintain patient compliance to ensure optimum effectiveness of the drug," said Dr. Henry Bone, director, Michigan Bone and Mineral Clinic and one of the principal investigators for the study. "This challenge is compounded for osteoporosis which often has no obvious symptoms unless significant skeletal damage already has occurred. One way to improve compliance is to increase the convenience of the drug therapy. These findings are exciting because a once-weekly medicine could provide an innovative and more convenient osteoporosis treatment for women whose busy schedules or need to take multiple medications make compliance difficult."

Currently, Fosamax is administered once daily for the prevention (5 mg) and treatment (10 mg) of postmenopausal osteoporosis. The drug is the only osteoporosis therapy approved to both increase bone mineral density and reduce the incidence of spine fractures and the potentially devastating fracture of the hip. As with other drugs in the same class known as bisphosphonates, however, food interferes with the absorption of Fosamax. As a result, it must be taken on an empty stomach with 6 ounces to 8 ounces of plain water at least 30 minutes before the first food of the day. Many women successfully incorporate this dosing regimen into their daily schedule.

Data also presented today from a large consumer research study of 450 women indicated that approximately 60 percent of women believe a once-weekly dosing option would be more convenient and help them continue taking their medicine as prescribed.

"Our hypothesis was that taking the same cumulative dose of Fosamax once a week would provide similar efficacy and tolerability to taking Fosamax once a day. The results of this study showed that the hypothesis was correct," Dr. Bone said.

The one-year, double-blind, multi-center study included 1258 women between the ages of 40 and 90 who were more than six months post menopause and had osteoporosis. Osteoporosis was defined as bone mineral density 2.5 standard deviations or more below the young adult mean at either the hip or spine, or a prior vertebral or hip fracture.

Women in the study were randomly assigned to one of three treatment groups: Fosamax administered 70 mg once weekly (n=519), Fosamax administered 35 mg twice weekly (n=369) or Fosamax administered 10 mg daily (n=370). All treatment groups received calcium and vitamin D supplements, which is recommended practice in osteoporosis management.

The primary endpoints of the study were change in bone mineral density at the lumbar spine, along with safety and tolerability. Secondary endpoints were change in bone mineral density at the hip and total body and effect on rate of bone turnover as assessed by biochemical markers. The results were compared between treatment groups to determine if the effects of the different treatment schedules were equivalent.

Before the study, standards were established for determining equivalence. At the end of one year these standards were met, with all regimens shown to be beneficial at all sites measured. The evaluation of the primary and secondary endpoints showed:

- Increases in bone mineral density at the lumbar spine, total hip and total body from baseline were similar between treatment groups suggesting therapeutic equivalence.

- At the spine the mean increase in bone mineral density from baseline was 5.4 percent for Fosamax 10 mg daily vs. 5.2 percent for Fosamax 35 mg twice weekly vs. 5.1 percent for Fosamax 70 mg once weekly.

The differences between treatment groups were not statistically significant.

- At the hip the mean increase in bone mineral density from baseline was 3.1 percent for Fosamax 10 mg daily vs. 3.4 percent for Fosamax 35 mg twice weekly vs. 2.9 percent for Fosamax 70 mg once weekly.

The differences between treatment groups were not statistically significant.

- For the total body the mean increase in bone mineral density from baseline was 1.0 percent for all treatment groups.

- Bone turnover markers, which are biochemical indicators of the rate of bone resorption (breakdown) and formation, also demonstrated similar changes in response to treatment with the three dosing regimens for Fosamax.

The safety and tolerability profiles were similar between treatment groups.

Like other drugs in the same class, known as bisphosphonates, Fosamax should be used with caution in people with certain stomach or digestive problems. Fosamax should not be used if the patient has certain disorders of the esophagus (the tube that connects the mouth with the stomach) that delay emptying, or if the patient is unable to stand or sit upright for at least 30 minutes. In addition, the medication should not be used in patients with severe kidney disease or low levels of calcium in their blood, in patients who are allergic to Fosamax or in patients who are pregnant or nursing.

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 those 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.

Like all prescription drugs, Fosamax may cause side effects. Side effects usually have been mild and generally have not caused patients to stop taking the drug.

A non-hormonal, bone-specific therapy, Fosamax has been studied in more than 17,000 patients in randomized clinical trials to advance the understanding of the prevention and treatment of osteoporosis. This investigational study of Fosamax in a once-weekly formulation continues the extensive clinical trials for the drug.

Fosamax was approved in the United States by the Food and Drug Administration (FDA) in 1995 for the treatment of osteoporosis in postmenopausal women (10 mg once daily) and for treatment of Paget's disease of bone (40 mg once daily). In 1997, Fosamax (5 mg once daily) was approved for the prevention of osteoporosis in postmenopausal women at risk of osteoporosis, and Fosamax (10 mg once daily) was approved for the prevention of fractures in postmenopausal women who have osteoporosis. In June 1999, Fosamax was approved as the first medication for treatment of glucocorticoid- induced osteoporosis in men and women receiving glucocorticoids (commonly referred to as corticosteroids or steroids) in a daily dosage equivalent to 7.5 mg or greater of prednisone and who have low bone mineral density. Fosamax is a product from Merck.

Related Links: Fosamax(R) (alendronate sodium) and Merck & Co., Inc.

---------------------------------------------------------------------------------------------   Copyright © 1999 P\S\L Consulting Group Inc. All rights reserved.

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