Focus on Medications That Rebuild Bone in Osteoporosis
By Richard Kilmartin
Debilitating fractures, often resulting from osteoporosis, greatly impact an individual’s quality of life. The anabolic osteoporosis agents (i.e., teriparatide, abaloparatide, romosozumab) are approved to reduce the risk of fracture in those considered to be at very high risk for osteoporotic fracture, including older adults with prior fragility fractures or low bone density scores (i.e., T-score of -2.5 or lower). To safely use them, we must understand their uses and limitations, including potential adverse effects. The following table provides a summary of some basic considerations for the currently available agents.
What’s different about these anabolic agents compared to older treatments? Most traditional osteoporosis therapies target a reduction in bone loss or turnover, whereas the anabolic osteoporosis agents primarily act by adding new bone. Healthy bone is constantly undergoing a process of regeneration where older bone is resorbed, and new bone is laid down in its place. This balance shifts as we age, creating a relative increase in bone loss. Individuals at the highest risk for fracture may have already lost significant bone at diagnosis, making the anabolic agents’ ability to add new bone particularly attractive.
All three anabolic agents are approved for the treatment of osteoporosis in postmenopausal women at high risk for fracture, or who failed or are intolerant to other treatments. Teriparatide is additionally approved for treatment of:
- men with primary or hypogonadal osteoporosis
- men and women with glucocorticoid-induced osteoporosis
As noted in the table above, these medications should not be given indefinitely. Additionally, for teriparatide and abaloparatide, lifetime use is cumulative, including all times when either was given. Therefore, it is important that a history of start dates and durations of therapy be maintained. Anabolic agents do not build bone indefinitely and an important point to remember is that once an anabolic osteoporosis treatment is discontinued, it should be followed by a medication that reduces further bone loss, such as a bisphosphonate (e.g., alendronate, risedronate) or denosumab. If follow-up therapy is not used, it is possible that the bone
density gains from the anabolic therapy will be lost over time with a resulting increase in fracture risk.
Those being treated for osteoporosis should receive adequate calcium and vitamin D, through diet or supplements, to maintain bone health during and after therapy. As with any medication, consideration must be given to potential adverse consequences and appropriate monitoring. The table below lists considerations and strategies to promote safe use of anabolic agents.
Anabolic osteoporosis agents offer another exciting method to treat those at the highest risk of fractures, especially in conjunction with proper monitoring and lifestyle modifications (e.g., adequate calcium and vitamin D, exercise, falls prevention).