Clinical Medicine Insights: Therapeutics

The prevalence of osteoporosis is likely to rise with the increase in life expectancy of an ageing population. Current first line therapies for the treatment of osteoporosis are predominantly anti-resorptive. Teriparatide is a first in class, anabolic agent with a unique mechanism that results in increased bone formation. Daily subcutaneous injection for 6–24 months was effective in reducing vertebral and non-vertebral fracture rates, in improving bone mineral density (BMD) and in increasing bone formation rates in postmenopausal osteoporosis, with effects persisting following treatment cessation. Similar benefits on bone mass and bone formation were seen in men with osteoporosis and glucocorticoid induced osteoporosis. Beneficial effects on bone mass have been demonstrated in treatment naive subjects treated with teriparatide alone, sequentially with anti-resorptive therapy and concomitantly with some, but not all, anti-resorptive treatments due to an early blunting of the anabolic effect. Teriparatide is generally well tolerated. However, the high treatment cost and inconvenient mode of administration has limited it's use to patients with osteoporosis who have experienced an unsatisfactory response, who are intolerant to other osteoporosis therapies, or to patients at very high risk of fracture. Teriparatide treatment is currently restricted to a total lifetime treatment dose of 18 months of daily subcutaneous therapy due to concerns from animal studies suggesting an increased risk of osteosarcoma. More safety data may permit a longer duration of treatment in the future but will necessitate prolonged human studies. Teriparatide may serve a more prominent role in the treatment of older patients who continue to fracture despite low bone turnover or sustain side effects with anti-resorptive therapy.