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Persistence is commonly considered a key factor for the successful management of osteoporosis and fragility fractures. Denosumab is the first biologic agent developed for the treatment of osteoporosis with satisfying data regarding the persistence with this therapy. The purpose of this multicenter observational real practice study was to evaluate the persistence with denosumab treatment in post-menopausal women affected by osteoporosis. Women were recruited in four specialized centers for the management of osteoporosis in North, Center and South of Italy. We included women with a diagnosis of post-menopausal osteoporosis, aged >50 years, able to obtain a prescription according to the Italian reimbursement criteria in force during the study period for anti-osteoporotic pharmacological treatment. They initiated a treatment with subcutaneous denosumab (Prolia®) 60 mg/every 6 months between November 2011 and May 2016. Women who had received aromatase inhibitors were excluded. Patients were assessed at baseline and every 6 months for all treatment length. Persistence data were evaluated for a total of 36 months. Eight hundred seventy women were enrolled; mean aged 70 years, with a mean body mass index of 24.8 ± 4.1 kg/m2. At the Dual-energy X-ray absorptiometry assessment, the mean lumbar spine T-score was −2.76 ± 1.14 standard deviations (SD) and the mean femoral neck T-score was −2.49 ± 0.80 SD. During the study, the total persistence was 91.4%. Total dropouts were 75 (8.6%), higher within the initial 6-month period of treatment. Persistence to denosumab treatment in our observational real practice study was very high. These results suggest that factors such as frequency of visits, pharmacological schedule, and opportunity to call the doctor might play an important role in the persistence and adherence to treatment to obtain maximum therapeutic effect and avoid further fragility fractures.

Excess of bone remodeling is still the major pathogenic factor in involutional osteoporosis. This phenomenon is linked to an imbalance between neoformation (by osteoblasts) and resorption (by osteoclasts). Recently, research in drug development is focused on new and more “physiological” approach to balance bone remodeling. The efficacy of denosumab was proved in the prevention of vertebral and non-vertebral fractures and related to the ability of the drug to penetrate in cortical and trabecular bone. Recently, data from several clinical studies confirm that denosumab improves fracture outcomes, also at skeletal sites rich in cortical bone.

Bone is a tissue that dynamically adapts mass and architecture to the mechanical loads that occur in daily life in a world with gravity. Bone architecture and mass are influenced by the applied tension peak, whereas the bone formation rate is modulated by the stimulus frequency. In bone tissue, osteocytes govern the detection of mechanical afferents and their transformation into biochemical messages, therefore these cells can be considered a mechanosensor that directs osteogenesis to where it is most needed to increase bone strength. The stimulation of osteocytes occurs with several modalities: shear stress and stretch, extracellular pressure modifications, strains, variations of electric field in and around osteocytes lacunae. The osteocyte network, under physiological conditions, activates osteoclastogenesis and suppresses osteoblast function enhancing bone resorption and inhibiting bone formation. In the unloaded condition, the functions of the osteocyte network are augmented, whereas exercise could decrease inhibitory effects on bone mass by reducing both osteoclastogenesis and inhibition on osteoblast function.

Aim of this study was to investigate whether osteoclast activity changes as a consequence of even mild physiological perturbation of plasma calcium as such induced by an oral calcium load. Osteoclast activity was determined indirectly by measuring, in spot urines at two and four hours after oral calcium load, the urinary excretion of hydroxylysylpyridinoline (Pyr), deoxylysylpyridinoline (D-Pyr), hydroxyproline (Hyp) and galactosyl-hydroxylysine (GHyl). The occurrence of the metabolic perturbation of plasma calcium homeostasis was assessed by measuring three indexes: i.e. calcemie response, PTH reduction and calciuric response at times following oral calcium loading. A significant fall of urinary D-Pyr and Pyr followed the perturbation of calcium homeostasis induced by the oral calcium load in two groups of healthy young adult and postmenopausal women. The highest mean percent reduction was observed for D-Pyr and was quantitatively similar in the two groups. Since urinary D-Pyr is the most specific bone resorption marker, it may be inferred that the perturbation of plasma calcium homeostasis induced by an oral calcium load is able to acutely inhibit osteoclast activity. This supports the view that osteoclasts are involved in the short-term error correction of plasma calcium.

Different types of calcitonin (porcine, human, salmon) are used in the management of bone diseases characterized by a high bone turnover, such as post-menopausal osteoporosis and Paget’s disease; recently, salmon calcitonin has become clinically available as an intranasal (i.n.) spray. An analgesic effect has also been described for calcitonins, both in experimental animals and humans, but only a few studies in humans were placebo controlled. The aim of this study was to compare the analgesic efficacy of i.n. and intramuscular (i.m.) salmon calcitonin (sCT) and of placebo in women affected by painful post-menopausal osteoporosis, in a double-blind, double-placebo trial. Twenty-eight women were randomly allocated to one of the following treatments: 1) i.n. sCT 200 U/day plus i.m. placebo; 2) i.n. placebo plus i.m. sCT 100 U/day; and 3) i.n. and i.m. placebo. Each treatment lasted four weeks, and the pain score was evaluated weekly by means of a visual analogic scale (VAS). Twenty-four women completed the trial; with i.n. sCT, the pain score decreased significantly by the second week of treatment (p<0.05); with i.m. sCT and with placebo, the pain score decreased significantly only by the fourth week (p<0.05), so that the final pain scores obtained with the three treatments were not different. We conclude that i.n. sCT was probably more rapid, but not more effective than i.m. sCT or placebo in decreasing pain in post-menopausal osteoporosis. (Aging Clin. Exp. Res. 6: 459-463, 1994)

It has been shown that human calcitonin (hCT) is absorbed through the nasal mucosa when administered together with promoters like sodium glycocholate (SGC) or dihydrofusinate. The aim of this study was to compare the clinical and metabolic effects of intranasal (in) and intramuscular (im) hCT in patients with osteoporosis or with Paget’s disease of bones. Fifteen women with postmenopausal or with senile osteoporosis entered a randomized six months trial with in hCT (plus SGC) or with im hCT 100 U on alternate days. Six women in each group were treated for 2 months, and only four women in each group continued treatment for an additional 4 months period. In hCT, but not im hCT, reduced subjective pain, while urinary cAMP increased to a similar extent in the 2 groups. Other metabolic indexes and bone mineral content (BMC) were unchanged, no new fractures took place, and side effects were fewer with in than with im hCT. To confirm the analgesic effect of in hCT, twelve patients with Paget’s disease of bones were randomly treated for 20 days with in or im hCT 100 U/day: during the short period of treatment, pain was reduced by in, not by im hCT, and urinary cAMP excretion similarly increased in the two groups of patients.