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EMBARGOED FOR RELEASE UNTIL 1:00 P.M. (CDT) ON SEPT. 19 STUDY SHOWS OSTEOPOROSIS TREATMENT WITH PTH ALONE IS MORE EFFECTIVE THAN COMBINATION TREATMENT

Minneapolis (Sept. 19, 2003)—Despite high expectations, new research reveals that combining parathyroid hormone (PTH) and alendronate, both popular drugs for treating osteoporosis, demonstrates no better results than either drug used alone. Furthermore, the combination of the two drugs does not show the expected increases in bone formation seen with PTH alone, according to a study presented today by Dennis Black, Ph.D., at the 25th Annual Meeting of the American Society for Bone and Mineral Research (ASBMR).

Osteoporosis is characterized by low bone mass and structural deterioration of bone tissue, leading to bone fragility and an increased susceptibility to fractures. FDA-approved drug treatments for osteoporosis have been shown to reduce the risk of fracture by up to 50 percent in as little as one year. Of these treatments, some slow the progressive deterioration of bone, such as alendronate and other bisphosphonates. PTH functions differently and actually helps rebuild the skeleton.

Investigators assigned 238 post-menopausal women then currently not using alendronate or another bisphosphonate to one of three daily treatment options: PTH
(100 µg rhPTH (1-84)) alone; alendronate (10 mg) alone; or a combination of the two. The women were treated and monitored for one year. They were measured for changes
in: (1) bone mineral density (BMD) using DXA scans of the spine and hip; (2) size and volume of bone mineralization using ultrasound; and (3) bone remodeling measured from biological markers of bone activity in the blood.

Dr. Black and his team had hypothesized that because the two drugs work through different mechanisms, combining the two would work much better than either alone. However, for DXA scans at the spine and hip, the combination did not perform better than either drug alone. Further, changes in three different measures – 1) BMD of the less dense, more elastic bone (trabecular) found in the horizontal bones of the spine, 2) volume of the protective outer bone (cortical) found in the hip, and 3) bone markers – suggest that the concurrent use of alendronate and PTH may actually diminish the bone-building effect of PTH. Large increases in markers of both bone breakdown (resorption) and formation were seen with PTH alone (146 percent and 104 percent, respectively), while PTH and alendronate combined yielded slight decreases in both measures (-16 percent and -14 percent, respectively).

The study suggests that patients who use PTH should not combine it with alendronate or other drugs that slow down bone breakdown; instead, they should use PTH alone. The study could not draw any conclusions regarding the use of drugs that slow down bone breakdown before or after PTH therapy. Longer term and larger studies are needed to determine if and how alendronate or other bisphosphonates might be optimally combined with PTH.

For more information on this study, visit www.asbmr.org.

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The ASBMR Annual Meeting is the pre-eminent scientific meeting on bone and mineral metabolism. Approximately 5,000 delegates attend the September 19-23 meeting, where nearly 1,700 scientific abstracts are being presented. The ASBMR is the premier professional, scientific and medical society established to promote excellence in bone and mineral research and to facilitate the translation of that research into clinical practice. The ASBMR has a membership of nearly 4,000 physicians, basic research scientists, and clinical investigators. To learn more about the Society and the field of bone and mineral research, visit the ASBMR website at www.asbmr.org.

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