Lessons from Bone Histomorphometry on the Mechanisms of Action of Osteoporosis Drugs

Histomorphometric changes following treatment for osteoporosis

“…The STAND trial compared denosumab to alendronate and showed that indices of bone turnover were lower in patients treated with denosumab than with alendronate, confirming the more potent antiresorptive effect of denosumab seen with biochemical markers [3]. Furthermore, it is important to note that the effects of denosumab A significant body of information is available regarding the effects of osteoporosis drugs on bone histomorphometry [1,2]. This is, in part, because regulatory agencies require biopsies to be performed to assess the safety and mechanism of action of new therapeutic agents.…”

“…As revealed by bone histomorphometry, each class has a fundamentally different mechanism of action. Antiresorptive therapies, such as estrogen, calcitonin, raloxifene, bisphosphonates, and denosumab, decrease bone turnover, lowering both resorption, and formation [2]. There are several histomorphometric studies on the effect of hormone therapy (HT) in postmenopausal women, providing convincing evidence of its beneficial skeletal action in preserving bone volume and structure by decreasing bone turnover.…”

“…Anabolic therapies work by a fundamentally different mechanism of action than antiresorptive agents [2,4] ( Fig. 1).…”