The importance of bisphosphonate therapy in maintaining bone mass in men after therapy with teriparatide [human parathyroid hormone(1–34)]

Teriparatide, the active fragment of human parathyroid hormone (hPTH 1–34), is an anabolic agent for the treatment of osteoporosis. Important questions remain regarding management strategy beyond the recommended 18- to 24-month course of teriparatide treatment. We followed 21 men for up to 2 years after discontinuing teriparatide. Twelve men (57%) chose treatment with bisphosphonate immediately after teriparatide withdrawal, while 9 (43%) opted for no pharmacologic agent. At the end of 1 year lumbar spine bone density increased an additional 5.1±1.0% in the bisphosphonate group, while it declined by 3.7±1.7% in those on no medication (P<0.002). In six men who delayed initiation of bisphosphonate until 1 year after teriparatide withdrawal, their subsequent gains in the second year, 2.6±1.7%, still placed them below the peak gains they achieved on teriparatide. In contrast, the 12 men who began bisphosphonates immediately and continued treatment for the entire 2-year post-PTH period had continued gains at the lumbar spine, 8.9±1.5% above their post-PTH values (P=0.002). For the 4-year period, including 2 years of teriparatide and 2 years of bisphosphonate, the total gains at the lumbar spine were 23.6±2.9%. Men, who received bisphosphonate in only the 2nd year post-teriparatide, had cumulative gains of 11.1±3.4%. Three men who did not receive any bisphosphonate at any time during the post-PTH period had cumulative gains of only 5.5±3.7%. These findings suggest that the use of bisphosphonates following teriparatide is an important component of any strategy utilizing this anabolic drug for osteoporosis in men. The immediate use of bisphosphonates after teriparatide withdrawal may help to optimize gains in bone density at the lumbar spine.