• change in hip bone mineral density [ Time Frame: study months 30 (phase A), 42 (phase B), 54 (phase C) ] [ Designated as safety issue: No ]
• change in forearm bone mineral density [ Time Frame: study months 30 (phase A), 42 (phase B), 54 (phase C) ] [ Designated as safety issue: No ]
• change in total body bone mineral [ Time Frame: study months 30 (phase A), 42 (phase B), 54 (phase C) ] [ Designated as safety issue: No ]
• change in femoral shaft bone mineral density [ Time Frame: study months 30 (phase A), 42 (phase B), 54 (phase C) ] [ Designated as safety issue: No ]
• change in serum PINP [ Time Frame: study months 0-30 (phase A), 30-42 (phase B), 42-54 (phase C) ] [ Designated as safety issue: No ]
• change in serum osteocalcin [ Time Frame: study months 0-30 (phase A), 30-42 (phase B), 42-54 (phase C) ] [ Designated as safety issue: No ]
• change in serum NTX [ Time Frame: study months 0-30 (phase A), 30-42 (phase B), 42-54 (phase C) ] [ Designated as safety issue: No ]
• incidence of hypercalcemia [ Time Frame: study months 0-30 (phase A), 30-42 (phase B), 42-54 (phase C) ] [ Designated as safety issue: Yes ]
• incidence of hypercalciuria [ Time Frame: study months 0-30 (phase A), 30-42 (phase B), 42-54 (phase C) ] [ Designated as safety issue: Yes ]
• incidence of symptoms [ Time Frame: study months 0-30 (phase A), 30-42 (phase B), 42-54 (phase C) ] [ Designated as safety issue: Yes ]

This study looks at the effects of two medications, alendronate and parathyroid hormone, on bone mass and on bone formation and bone breakdown in women with osteoporosis. We will randomly select postmenopausal women who have osteoporosis to receive laboratory-produced human parathyroid hormone (hPTH), or alendronate, or both for 2.5 years. Study participants will return to the study center periodically to have their bone mass measured and to give blood and urine samples for tests of bone formation and breakdown and for other laboratory tests. Those who complete the study are eligible for one or two 12 month extension studies.

This is a randomized, prospective, open-label study in which osteoporotic postmenopausal women self-administer synthetic hPTH-(1-34), alendronate, or both, every day for 2.5 years. Participants initially come to Massachusetts General Hospital once a month, and subsequently once every 3-6 months, for measurements of serum and urine indices of bone formation and resorption, serum and urine toxicity tests, and DXA/QCT measurements of bone mass. One-third of the participants take hPTH-(1-34) daily, one-third take alendronate once daily, and one-third take both daily (Phase A, months 0-30).

Participants who complete Phase A are eligible for a 12 month extension study (Phase B, months 30-42), during which any alendronate treatment is continued without change and any hPTH 1-34 treatment is stopped.

Participants who complete Phase B are eligible for a second 12 month extension study (Phase C, months 42-54), during which any alendronate treatment is continued without change and every participant takes hPTH 1-34.

During Phases B and C, these participants come to Massachusetts General Hospital once every 6 months for measurements of serum and urine indices of bone formation and resorption, serum and urine toxicity tests, and DXA/QCT measurements of bone mass.

• Drug: Human parathyroid hormone [hPTH-(1-34)]
• Drug: alendronate

• Experimental: Human parathyroid hormone [hPTH-(1-34)]
• Active Comparator: Alendronate
• Experimental: Human parathyroid hormone [hPTH-(1-34)] plus alendronate

Inclusion Criteria:

• Lumbar spine or hip BMD T-score less than or equal to minus 2.0
• Postmenopausal at least 5 years
• Fully ambulatory
• Able to give informed consent

Exclusion Criteria:

• No concurrent illnesses that cause bone loss
• No recent drug treatment for osteoporosis
• No recent fracture