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Aging of the general population has led to a substantial increase in the prevalence of osteoporosis over the past decades. While there are effective pharmacological agents that increase bone formation, decrease bone resorption, and decrease fracture risk, they do not uniformly cure osteoporosis. This has prompted investigations to examine whether combination therapy (COMBO) with these agents can result in an additive benefit. Since concomitant therapy with denosumab and teriparatide has shown promise in this respect, investigations were undertaken to explore whether the changes in osteogenic phenotype could provide insight into the cellular and molecular mechanism of this effect. Investigations were performed in postmenopausal women receiving denosumab, teriparatide, or both for 3 months. Histomorphometric parameters were the primary outcome, while exploratory studies examined RNA expression in bone biopsies as well as in sorted and cultured bone marrow stromal cells (BMSCs). Osteogenic colony forming units of BMSCs were also evaluated. The studies demonstrated that COMBO results in an increase in osteoprogenitors, evidenced by an increase in osteoblastic colony-forming units. This was associated with an increased in BMSC expression of LGR6 (leucine-rich repeat containing G protein-coupled receptor 6), a stem cell marker and activator of the canonical Wnt signaling pathway. These data suggest that enhancement of canonical Wnt signaling contributes to the increase in osteoprogenitors and consequently an increase in bone density in postmenopausal women receiving COMBO for osteoporosis., (© The Author(s) 2024. Published by Oxford University Press on behalf of the Endocrine Society. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com. See the journal About page for additional terms.)

Context: Patients with osteoporosis and advanced chronic kidney disease (CKD) are at increased risk for hypocalcemia when initiating denosumab. It remains unclear if subsequent doses of denosumab pose similar hypocalcemia risk as the initial dose does., Objectives: To study dose-specific hypocalcemia risks of denosumab., Design, Setting, Patients and Exposure: An observational study of 10,398 consecutive patients with varying renal function who received denosumab within Mass General Brigham healthcare system between 1/1/2016 and 2/29/2024., Main Outcomes and Measures: Dose-specific effects of denosumab on serum calcium levels and incidence of hypocalcemia (albumin-corrected serum calcium level < 8.5 mg/dl)., Results: In 159 patients with sufficient data for three consecutive doses of denosumab, the initial dose of denosumab reduced serum calcium levels by an average of 0.34, 0.52, and 1.12 mg/dl, in patients with GFR of ≥60 (n=89), 30-59 (n=46) and < 30 (n=24) ml/min/1.73m2, respectively (p<0.001). Among patients with GFR of < 30 ml/min/1.73m2, the initial, second, and third dose of denosumab reduced serum calcium levels by an average of 1.12, 0.72, and 0.60 mg/dl, respectively (p=0.014).In a cohort of 325 patients with sufficient data for two doses of denosumab, a Kaplan-Meier analysis revealed a trend of higher incidence of hypocalcemia following the initial dose compared to the second dose in patients with GFR of < 30 ml/min/1.73m2., Conclusions: The magnitude of serum calcium decrease following subsequent dose(s) was smaller than that following the initial dose of denosumab among patients with osteoporosis and advanced CKD., (© The Author(s) 2024. Published by Oxford University Press on behalf of the Endocrine Society. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com. See the journal About page for additional terms.)

Inpatient zoledronic acid (IP-ZA) administered during the initial fracture hospitalization significantly improves the osteoporosis treatment rate. Clinical outcomes of IP-ZA after hip fracture remain uncertain. Here we report a cohort study that emulated a randomized controlled trial using real-world data and evaluated the risk of all-cause-mortality and radiologically confirmed subsequent new fractures among patients hospitalized for a hip fracture who had received IP-ZA as compared with propensity-matched controls. A total of 654 patients who had received IP-ZA and 6877 controls (for whom anti-osteoporosis treatment was indicated but no IP-ZA started during index hospitalization) were included in the study. The primary cohort comprised 652 IP-ZA patients (IP-ZA group) and 1926 matched controls (untreated group), with 71.7% female 92.1% White participants, with a mean age of 80.9 years. Cumulative all-cause mortality over the 24-month follow-up for the IP-ZA group was 12.3% and 20.7% for the untreated group (hazard ratio [HR], 0.62; 95% CI, 0.49-0.78, p < .001). A total of 585 (89.7%) patients in IP-ZA group received only a single dose of ZA during the 24 months, and the death rate of this single dose group was 13.3%, which was significantly lower than that of the untreated group (HR, 0.70; 95% CI, 0.55-0.89, p = .003). Rates of radiologically confirmed cumulative subsequent new vertebral fractures were 2.0% in the IP-ZA group and 5.4% in the untreated group (HR, 0.40; 95% CI, 0.22-0.71, p = .001). A similarly lower rate of new vertebral fractures was seen in the single dose subgroup (1.9% vs 5.4%; HR, 0.44; 95% 0.24-0.82, p = .008). IP-ZA, administered during the initial hospitalization for hip fracture, was associated with lower all-cause-mortality and risk of radiologically confirmed subsequent new vertebral fractures, and thus offers a mechanism to narrow the treatment gap in patients having sustained a hip fragility fracture., (© The Author(s) 2024. Published by Oxford University Press on behalf of the American Society for Bone and Mineral Research. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

When denosumab is discontinued, antiresorptive therapy is critical to reduce high-turnover bone loss. The ideal duration of antiresorptive therapy after denosumab is uncertain. This study demonstrates that both 1 and 2 years of alendronate maintained bone density gains achieved with 1 year of denosumab., Background: When denosumab is discontinued, antiresorptive therapy is critical to attenuate high-turnover bone loss. The ideal choice and duration of antiresorptive therapy are not yet defined, however. In the Comparison of Alendronate or Raloxifene following Denosumab (CARD) study, we demonstrated that 12 months of alendronate was better able to maintain the bone mineral density (BMD) gains achieved with 12 months of denosumab versus 12 months of raloxifene. In this extension, we wished to determine if 12 months of alendronate would be sufficient in maintaining these denosumab-induced BMD gains., Methods: In the CARD study, postmenopausal osteoporotic women aged 60-79 at high fracture risk received 12 months of denosumab 60-mg SC every 6 months followed by 12 months of either alendronate 70 mg weekly (N = 26) or raloxifene (N = 25). All subjects in the alendronate arm were then offered participation in a 1-year extension in which they were randomized to continue alendronate for an additional 12 months (N = 10) or to receive calcium and vitamin D alone (N = 8). The primary outcome was change in spine BMD between months 24 and 36. Exploratory endpoints included changes in areal BMD (aBMD) at other anatomic sites as well as changes in serum bone turnover markers., Results: The CARD study demonstrated the effectiveness of 12 months alendronate in preserving denosumab-induced BMD gains. In the extension, aBMD was maintained at the spine, total hip, and femoral neck in both those randomized to an additional year of alendronate and those randomized to calcium/vitamin D alone. We did, however, observe a transient comparative decrease between months 24-30 in the calcium/vitamin D group at the total hip (P = 0.008) and femoral neck (P = 0.040). At the end of 24 months of the CARD study, bone turnover markers serum c-telopeptide (CTX) and procollagen N-propeptide of type I collagen (PINP) were suppressed in both groups and then increased more between months 24-36 in the calcium/vitamin D group than the alendronate group (P = 0.051 for CTX, P = 0.030 for P1NP). Both CTX and PINP remained below the month 0 baseline in both groups (P < 0.05 for all comparisons)., Conclusions: With the limitations of our small sample size, these data suggest that both 1 and 2 years of alendronate effectively maintain BMD gains achieved with 1 year of denosumab and prevented any rebound in bone turnover marker levels above pre-denosumab baseline. This is the first randomized trial to assess minimum duration of bisphosphonate after short-term denosumab and may be helpful to guide clinical care. Similar studies performed after longer durations of denosumab would be helpful to further define optimal management., Trial Registration: ClinicalTrials.gov registration number: NCT03623633., (© 2024. International Osteoporosis Foundation and Bone Health and Osteoporosis Foundation.)

Background: Osteoporosis is a chronic progressive disease that requires lifelong monitoring and treatment. Sequencing from one treatment to another at different ages and stages of disease is an approach that can maximize benefits and avoid potential risks from long-term treatment with a single agent., Objective: This article reviews clinical trial data in postmenopausal women that evaluate the effects of antiresorptive agents followed by other antiresorptives, osteoanabolic agents followed by antiresorptives, and antiresorptives followed by osteoanabolic medications., Methods: Literature review and discussion., Results: When medications are discontinued, in the absence of sequential therapy, bone turnover rates return to baseline or above baseline, and bone loss occurs. The rate of bone loss differs for different treatments, with a very slow decline after stopping bisphosphonates and a particularly rapid decline after stopping denosumab. Careful attention to osteoporosis medication transitions can mitigate bone density loss and its consequences. For women who remain at high risk, switching from bisphosphonates to the more potent antiresorptive, denosumab, will result in further improvement in bone mineral density (BMD). When indicated, stopping denosumab can be accomplished safely by transition to an adequate bisphosphonate regimen. For high- and very-high-risk patients, treating with osteoanabolic agents first, followed by antiresorptive agents, produces substantially larger BMD gains than the reverse treatment sequence, with the biggest differences seen for BMD of the hip., Conclusion: Awareness of the importance of treatment sequences can help improve osteoporosis care across the postmenopausal lifespan., Competing Interests: Disclosure The authors have no multiplicity of interest to disclose. Felicia Cosman: Consultant for Amgen, Enterabio, Biocon, Curateq, Pfizer, and UCB; Grant Recipient from Radius Health; Speaker for Amgen and Radius Health. Bente Langdal: Research grants from Amgen; advisory boards and lectures for UCB, Amgen, Gedeon-Richter, Astra-Zeneca, Astellas, Samsung-Bioepis. Benjamin Leder: Consultant for Amgen and Radius Health., (Copyright © 2024. Published by Elsevier Inc.)

Context: Addressing vitamin D deficiency (VDD) is important for fracture secondary prevention., Objectives: To explore the function of a fracture liaison service (FLS) to address VDD., Design Setting and Patients: An observational study of patients admitted to the Massachusetts General Hospital with fractures between January 1, 2016, and October 31, 2023, cared for by the FLS., Intervention: Ergocalciferol 50 000 international units (50ku-D2) oral daily for 3 to 7 days., Main Outcomes Measures: VDD prevalence. Efficacy of inpatient daily 50ku-D2 in raising serum 25-hydroxyvitamin D (25OHD) levels., Results: Of the 2951 consecutive patients, 724 (24.53%) had VDD (defined by 25OHD ≤ 19 ng/mL). Men (252/897, or 28.09%) were more likely than women (472/2054, or 22.98%) to have VDD ( P = .003). VDD was seen in 41.79% (117/280), 24.41% (332/1360), and 20.98% (275/1311) of patients of aged ≤59, 60 to 79, and ≥80 years, respectively ( P < .00001). Of the 1303 patients with hip fractures, 327 (25.09%) had VDD, which was associated with a longer length of stay (8.37 ± 7.35 vs 7.23 ± 4.78 days, P = .009) and higher trend of 30-day-readmission rate (13.63% vs 18.35%, P = .037). In a cohort of 32 patients with complete data, each dose of 50ku-D2 increased serum 25OHD by 3.62 ± 2.35 ng/mL without affecting serum calcium or creatinine levels., Conclusion: VDD was seen in nearly 25% of Massachusetts General Hospital FLS patients and more prevalent in male and younger patients. VDD was associated with longer length of stay and higher 30-day-readmission risk in patients with hip fracture. Daily 50ku-D2 appeared to be a practical way to quickly replete vitamin D in the inpatient setting., (© The Author(s) 2024. Published by Oxford University Press on behalf of the Endocrine Society.)

Denosumab discontinuation results in accelerated bone remodeling, decreased bone mineral density (BMD), and an increased risk of multiple vertebral fractures. Bisphosphonates are at least partially effective at inhibiting these consequences but there have been no randomized clinical trials assessing the efficacy of alternative antiresorptives., Purpose: The aim of this study was to evaluate the comparative efficacy of alendronate and the SERM, raloxifene, in preventing the post-denosumab high-turnover bone loss., Methods: We conducted an open-label randomized controlled trial in which 51 postmenopausal women at increased risk of fracture were randomized with equal probability to receive 12-months of denosumab 60-mg 6-monthly followed by 12-months of either alendronate 70-mg weekly or raloxifene 60-mg daily. Serum bone remodeling markers were measured at 0,6,12,15,18, and 24 and areal BMD of the distal radius, spine, and hip were measured at 0,12,18 and 24 months., Results: After denosumab discontinuation, serum markers of bone remodeling remained suppressed when followed by alendronate, but gradually increased to baseline when followed by raloxifene. In the denosumab-to-alendronate group, denosumab-induced BMD gains were maintained at all sites whereas in the denosumab-to-raloxifene group, BMD decreased at the spine by 2.0% (95% CI -3.2 to -0.8, P = 0.003) and at the total hip by 1.2% (-2.1 to -0.4%, P = 0.008), but remained stable at the femoral neck and distal radius and above the original baseline at all sites. The decreases in spine and total hip BMD in the denosumab-to-raloxifene group (but not the femoral neck or distal radius) were significant when compared to the denosumab-to-alendronate group., Conclusions: These results suggest that after one year of denosumab, one year of alendronate is better able to maintain the inhibition of bone remodeling and BMD gains than raloxifene., (© 2023. International Osteoporosis Foundation and Bone Health and Osteoporosis Foundation.)

Osteoporosis is a chronic condition characterized by decreased bone mass, loss of skeletal integrity, and increased susceptibility to fracture. Drugs used to treat osteoporosis can be classified as those that block bone resorption (antiresorptive), stimulate bone formation (anabolic), or do both. While all currently approved medications reduce the risk of fragility fractures in high-risk populations, they are generally unable to fully restore bone strength in most patients with established disease. Thus, the majority of patients require disease management over many years. Unfortunately, the continuous use of a single drug has limitations, both in terms of efficacy and safety, and so sequential therapy is commonly required. Given the expanding list of pharmacological agents currently available, careful consideration needs to be given as to which drugs to use and in what sequence. This review will evaluate the differential effects of antiresorptive, bone-forming, and dual-acting drugs when used in specific sequences and will explore the current evidence favoring the initial use of bone-forming/dual-acting drugs followed by antiresorptive medications. This review will also examine the notion that long-term treatment with an antiresorptive drug may diminish the efficacy of subsequent treatment with a bone-forming/dual-acting drug. Finally, this review will explore the current evidence pertaining to the specific issue of how to best prevent the clinical ramifications of denosumab cessation., (© The Author(s) 2023. Published by Oxford University Press on behalf of the Endocrine Society. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Context: Zoledronic acid (ZA) administered during the initial hospitalization for a fragility fracture improves the osteoporosis pharmacotherapy rate. Distinguishing the safety profile of inpatient ZA (IP-ZA) in this context is crucial if this approach is to be widely adopted., Objective: To study the acute safety profile of IP-ZA., Methods: An observational study of patients admitted to the Massachusetts General Hospital with fragility fractures who were eligible to receive IP-ZA. Patients were treated with or without IP-ZA. Acetaminophen, either as a single pre-ZA dose or standing multiple-doses-per-day regimen for 48 hours or longer after ZA infusion, was also administered along with protocolized vitamin D and calcium supplementation. Changes in body temperature, serum creatinine, and serum calcium were measured., Results: A total of 285 consecutive patients, meeting inclusion and exclusion criteria, are included in this analysis; 204 patients received IP-ZA. IP-ZA treatment was associated with a transient mean rise of body temperature of 0.31 °C on the day following its administration. Temperatures above 38 °C were seen in 15% of patients in the IP-ZA group and 4% in the nontreated group. Standing multiple-doses-per-day but not a single pre-ZA dose of acetaminophen effectively prevented this temperature increase. IP-ZA did not affect serum creatinine levels. Mean levels of serum total calcium and albumin-corrected calcium decreased by 0.54 mg/dL and 0.40 mg/dL, respectively, at their nadirs (Day 5). No patient experienced symptomatic hypocalcemia., Conclusion: IP-ZA along with standing multiple-doses-per-day acetaminophen, administered to patients in the immediate postfracture period, is not associated with significant acute adverse effects., (© The Author(s) 2023. Published by Oxford University Press on behalf of the Endocrine Society. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

The combination of denosumab and teriparatide is an effective treatment strategy in postmenopausal osteoporosis, though skeletal gains are promptly lost when these agents are discontinued. In the DATA-HD study, we reported that a single dose of zoledronic acid (ZOL) maintains the increases in areal spine and hip bone mineral density (BMD) achieved with this combination for at least 12 months. The capacity of ZOL to maintain corresponding improvements in peripheral volumetric BMD and microarchitecture, however, has not been reported. In the 15-month DATA-HD study, 76 postmenopausal osteoporotic women were randomized to receive 9 months of teriparatide (20-μg or 40-μg daily) overlapped with denosumab (60 mg at months 3 and 9). In the Extension study, 53 participants received a single dose of ZOL (5 mg intravenously) 24-35 weeks after the last denosumab dose. We measured volumetric BMD and microarchitecture at the distal radius and tibia using high-resolution peripheral quantitative computed tomography at months 27 and 42. Despite ZOL administration, total and cortical BMD gradually decreased over 27 months resulting in values similar to baseline at the radius but still significantly above baseline at the tibia. At both sites, cortical porosity decreased to values below pretreatment baseline at month 27 but then increased from month 27 to 42. There were no significant changes in trabecular parameters throughout the 27-month post-ZOL observation period. Stiffness and failure load, at both sites, decreased progressively from month 15 42 though remained above baseline at the tibia. These findings suggest that in contrast to the largely maintained gains in dual-energy X-ray absorptiometry (DXA)-derived spine and hip BMD, a single dose of ZOL was not as effective in maintaining the gains in volumetric peripheral bone density and microarchitecture produced by 15 months of overlapping treatment with denosumab and teriparatide. Alternative therapeutic approaches that can fully maintain improvements in peripheral bone parameters require further study. © 2022 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR)., (© 2022 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).)

Context: Fragility fractures increase risks for future fractures, morbidity, and mortality. Available pharmacotherapy for underlying osteoporosis is safe and effective but underused., Objective: To improve pharmacotherapy rate representing secondary prevention of osteoporotic fractures., Methods: This single-center, observational, follow-up study included patients with fragility fractures admitted to the Massachusetts General Hospital between February 2016 and December 2019. For patients admitted to the orthopedics service with fragility fracture, the Massachusetts General Hospital Fracture Liaison Service (FLS) was systematically consulted. Initial outpatient follow-up with FLS was established in conjunction with the orthopedic postoperative follow-up visit. Patients at risk for failing timely outpatient follow-up were administered zoledronic acid (ZA) during the index fracture hospitalization. The main outcome measures were percentage of patients with fragility fracture(s) started on pharmacotherapy for osteoporosis and average length of stay and 30-day readmission rate of patients treated with ZA., Results: Compared with baseline (8-11%) and reference (5-20%) rates, integration of FLS to the orthopedics service, along with appropriate inpatient administration of ZA, increased the pharmacotherapy rate to 70% (412/589) among eligible patients with verified treatment status. Inpatient ZA administration neither affected the average length of stay nor 30-day readmission rate. Treatment status of 37.9% (471/1240) of the study patients remained unknown due to lack of or unknown follow-up., Conclusion: Integration of a FLS and orthopedics services along with inpatient ZA administration improved the osteoporosis pharmacotherapy rate among patients with fragility fracture(s) who often had obstacles for outpatient follow-up., (© The Author(s) 2022. Published by Oxford University Press on behalf of the Endocrine Society. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

To evaluate whether treatment sequence affects romosozumab response, this analysis reviewed studies where romosozumab was administered before or following an antiresorptive (alendronate or denosumab). Initial treatment with romosozumab followed by an antiresorptive resulted in larger increases in bone mineral density of both hip and spine compared with the reverse sequence., Introduction: Teriparatide followed by an antiresorptive increases bone mineral density (BMD) more than using an antiresorptive first. To evaluate whether treatment sequence affects romosozumab response, we reviewed randomized clinical trials where romosozumab was administered before (ARCH, FRAME) or following (STRUCTURE, Phase 2 extension) an antiresorptive (alendronate or denosumab, respectively)., Methods: We evaluated BMD percentage change for total hip (TH) and lumbar spine (LS) and response rates (BMD gains ≥ 3% and ≥ 6%) at years 1 and 2 (except STRUCTURE with only 1-year data available)., Results: With 1-year romosozumab initial therapy in ARCH and FRAME, TH BMD increased 6.2% and 6.0%, and LS BMD increased 13.7% and 13.1%, respectively. When romosozumab was administered for 1 year after alendronate (STRUCTURE) or denosumab (Phase 2 extension), TH BMD increased 2.9% and 0.9%, respectively, and LS BMD increased 9.8% and 5.3%, respectively. Over 2 years, TH and LS BMD increased 7.1% and 15.2% with romosozumab/alendronate, 8.5% and 16.6% with romosozumab/denosumab, and 3.8% and 11.5% with denosumab/romosozumab, respectively. A greater proportion of patients achieved BMD gains ≥ 6% when romosozumab was used first, particularly for TH, versus the reverse sequence (69% after romosozumab/denosumab; 15% after denosumab/romosozumab)., Conclusion: In this study, larger mean BMD increases and greater BMD responder rates were achieved when romosozumab was used before, versus after, an antiresorptive agent. Since BMD on treatment is a strong surrogate for bone strength and fracture risk, this analysis supports the thesis that initial treatment with romosozumab followed by an antiresorptive will result in greater efficacy versus the reverse sequence., (© 2022. The Author(s).)

Combined teriparatide and denosumab rapidly and substantially increases bone mineral density (BMD) at all anatomic sites. Discontinuation of denosumab however, results in high-turnover bone loss and increased fracture risk. The optimal way to prevent this bone loss remains undefined. This study is a preplanned extension of the DATA-HD study, where postmenopausal women with osteoporosis were randomized to receive 9 months of either 20 μg or 40 μg of teriparatide daily overlapping with denosumab (60 mg administered at months 3 and 9). At the completion of this 15-month study, women were invited to enroll in the DATA-HD Extension where they received a single dose of zoledronic acid (5 mg) 24 to 35 weeks after the last denosumab dose. Areal BMD and bone turnover markers were measured at month 27 and 42 (12 and 27 months after zoledronic acid, respectively) and spine and hip volumetric bone density by quantitative CT was measured at month 42. Fifty-three women enrolled in the DATA-HD Extension. At the femoral neck and total hip, the mean 5.6% and 5.1% gains in BMD achieved from month 0 to 15 were maintained both 12 and 27 months after zoledronic acid administration. At the spine, the mean 13.6% gain in BMD achieved from month 0 to 15 was maintained for the first 12 months but modestly decreased thereafter, resulting in a 3.0% reduction (95% CI, -4.0% to -2.0%, p < .0001) 27 months after zoledronic acid. The pattern of BMD changes between months 15 and 42 were qualitatively similar in the 20-μg and 40-μg groups. A single dose of zoledronic acid effectively maintains the large and rapid total hip and femoral neck BMD increases achieved with combination teriparatide/denosumab therapy for at least 27 months following the transition. Spine BMD was also largely, though not fully, maintained during this period. These data suggest that the DATA-HD Extension regimen may be an effective strategy in the long-term management of patients at high risk of fragility fracture. © 2021 American Society for Bone and Mineral Research (ASBMR)., (© 2021 American Society for Bone and Mineral Research (ASBMR).)

Anabolic osteoporosis drugs improve bone mineral density by increasing bone formation. The objective of this study was to evaluate the early effects of abaloparatide on indices of bone formation and to assess the effect of abaloparatide on modeling-based formation (MBF), remodeling-based formation (RBF), and overflow MBF (oMBF) in transiliac bone biopsies. In this open-label, single-arm study, 23 postmenopausal women with osteoporosis were treated with 80 μg abaloparatide daily. Subjects received double fluorochrome labels before treatment and before biopsy collection at 3 months. Change in dynamic histomorphometry indices in four bone envelopes were assessed. Median mineralizing surface per unit of bone surface (MS/BS) increased to 24.7%, 48.7%, 21.4%, and 16.3% of total surface after 3 months of abaloparatide treatment, representing 5.5-, 5.2-, 2.8-, and 12.9-fold changes, on cancellous, endocortical, intracortical, and periosteal surfaces (p < .001 versus baseline for all). Mineral apposition rate (MAR) was significantly increased only on intracortical surfaces. Bone formation rate (BFR/BS) was significantly increased on all four bone envelopes. Significant increases versus baseline were observed in MBF on cancellous, endocortical, and periosteal surfaces, for oMBF on cancellous and endocortical surfaces, and for RBF on cancellous, endocortical, and intracortical surfaces. Overall, modeling-based formation (MBF + oMBF) accounted for 37% and 23% of the increase in bone-forming surface on the endocortical and cancellous surfaces, respectively. Changes from baseline in serum biomarkers of bone turnover at either month 1 or month 3 were generally good surrogates for changes in histomorphometric endpoints. In conclusion, treatment with abaloparatide for 3 months stimulated bone formation on cancellous, endocortical, intracortical, and periosteal envelopes in transiliac bone biopsies obtained from postmenopausal women with osteoporosis. These increases reflected stimulation of both remodeling- and modeling-based bone formation, further elucidating the mechanisms by which abaloparatide improves bone mass and lowers fracture risk. © 2021 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR)., (© 2021 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).)

Osteogenesis imperfecta (OI), a heritable disorder caused by abnormalities in synthesis or processing of type I collagen, is characterized by skeletal fragility. Type I collagen interacts with multiple components of the extracellular matrix (ECM) including other collagens types. Thus, alterations in structure or quantity may broadly affect ECM homeostasis. In fact, while OI is clinically categorized by severity of bone disease, patients can also present with extra-skeletal manifestations, including the pulmonary, muscle and cardiovascular systems. Parathyroid hormone (PTH) is a regulator of skeletal homeostasis but the receptor for PTH/PTH1R is expressed in a variety of other tissues. Given interactions between type I collagen with other collagens in the ECM and the potential for PTH action on tissues beyond the skeleton, we explored whether serum levels of non-type I collagens are altered in response to teriparatide (human parathyroid hormone 1-34). We measured biomarkers of collagens II, III, IV, V, and VI in serum from individuals with type I and types III/IV OI in response to an 18 month course of teriparatide or placebo. These results were compared to similar biomarker measures in postmenopausal (PM) women without OI treated with teriparatide. In type I OI, teriparatide therapy increased concentrations of biomarkers of collagens II, III, IV, V, and VI. In individuals with types III/IV OI these biomarker changes in response to teriparatide were blunted, as we previously reported with collagen I biomarkers during teriparatide therapy. In contrast to OI, in PM women there were no effects of teriparatide on the collagen biomarkers we assessed (II, V, and VI). These findings suggest that in OI teriparatide therapy has abnormal effects on the homeostasis of many ECM collagens likely derived from skeletal as well as extra-skeletal tissues., (Copyright © 2020. Published by Elsevier Inc.)

In postmenopausal women at high risk of fracture, we previously reported that combined denosumab and high-dose (HD; 40 μg) teriparatide increased spine and hip bone mineral density (BMD) more than combination with standard-dose teriparatide (SD; 20 μg). To assess the effects of these combinations on bone microarchitecture and estimated bone strength, we performed high-resolution peripheral quantitative computed tomography (HR-pQCT) at the distal radius and distal tibia in these women, who were randomized to receive either teriparatide 20 μg (n = 39) or 40 μg (n = 37) during months 0 to 9 overlapped with denosumab 60 mg s.c. given at months 3 and 9, for a 15-month study duration. The 69 women who completed at least one study visit after baseline are included in this analysis. Over 15 months, increases in total BMD were higher in the HD-group than the SD-group at the distal tibia (5.3% versus 3.4%, p = 0.01) with a similar trend at the distal radius (2.6% versus 1.0%, p = 0.06). At 15 months, cortical porosity remained similar to baseline, with absolute differences of -0.1% and -0.7% at the distal tibia and -0.4% and -0.1% at the distal radius in the HD-group and SD-group, respectively; p = NS for all comparisons. Tibial cortical tissue mineral density increased similarly in both treatment groups (1.3% [p < 0.0001 versus baseline] and 1.5% [p < 0.0001 versus baseline] in the HD-group and SD-group, respectively; p = 0.75 for overall group difference). Improvements in trabecular microarchitecture at the distal tibia and estimated strength by micro-finite element analysis at both sites were numerically greater in the HD-group compared with SD-group but not significantly so. Together, these findings suggest that short-term treatment combining denosumab with either high- or standard-dose teriparatide improves HR-pQCT measures of bone density, microstructure, and estimated strength, with greater gains in total bone density observed in the HD-group, which may be of benefit in postmenopausal women with severe osteoporosis. © 2020 American Society for Bone and Mineral Research (ASBMR)., (© 2020 American Society for Bone and Mineral Research (ASBMR).)

Background: Denosumab is effective for osteoporosis, but discontinuation leads to rapid reversal of its therapeutic effect., Objective: To estimate the risk for fracture among users of denosumab who delayed subsequent doses compared with users who received doses on time., Design: Population-based cohort study., Setting: The Health Improvement Network U.K. primary care database, 2010 to 2019., Patients: Persons aged 45 years or older who initiated denosumab therapy for osteoporosis., Measurements: Observational data were used to emulate an analysis of a hypothetical trial with 3 dosing intervals: subsequent denosumab injection given within 4 weeks after the recommended date ("on time"), delay by 4 to 16 weeks ("short delay"), and delay by more than 16 weeks ("long delay"). The primary outcome was a composite of all fracture types at 6 months after the recommended date. Secondary outcomes were major osteoporotic fracture, vertebral fracture, hip fracture, and nonvertebral fracture., Results: Investigators identified 2594 patients initiating denosumab therapy. The risk for composite fracture over 6 months was 27.3 in 1000 for on-time dosing, 32.2 in 1000 for short delay, and 42.4 in 1000 for long delay. Compared with on-time injections, short delay had a hazard ratio (HR) for composite fracture of 1.03 (95% CI, 0.63 to 1.69) and long delay an HR of 1.44 (CI, 0.96 to 2.17) ( P for trend = 0.093). For vertebral fractures, short delay had an HR of 1.48 (CI, 0.58 to 3.79) and long delay an HR of 3.91 (CI, 1.62 to 9.45)., Limitation: Dosing schedules were not randomly assigned., Conclusion: Although delayed administration of subsequent denosumab doses by more than 16 weeks is associated with increased risk for vertebral fracture compared with on-time dosing, evidence is insufficient to conclude that fracture risk is increased at other anatomical sites with long delay., Primary Funding Source: National Clinical Research Center for Orthopedics, Sports Medicine & Rehabilitation.

Context: Most labs set the lower limit of normal for testosterone at the 2.5th percentile of values in young or age-matched men, an approach that does not consider the physiologic changes associated with various testosterone concentrations., Objective: To characterize the dose-response relationships between gonadal steroid concentrations and measures regulated by gonadal steroids in older men., Design, Participants, and Intervention: 177 men aged 60 to 80 were randomly assigned to receive goserelin acetate plus either 0 (placebo), 1.25, 2.5, 5, or 10 grams of a 1% testosterone gel daily for 16 weeks or placebos for both medications (controls)., Primary Outcomes: Changes in serum C-telopeptide (CTX), total body fat by dual energy X-ray absorptiometry, and self-reported sexual desire., Results: Clear relationships between the testosterone dosage (or the resulting testosterone levels) and a variety of outcome measures were observed. Changes in serum CTX exceeded changes in the controls in men whose testosterone levels were 0 to 99, 100 to 199, 200 to 299, or 300 to 499 ng/dL, whereas increases in total body fat, subcutaneous fat, and thigh fat exceeded controls when testosterone levels were 0 to 99 or 100 to 199 ng/dL. Sexual desire and erectile function were indistinguishable from controls until testosterone levels were <100 ng/dL., Conclusion: Changes in measures of bone resorption, body fat, and sexual function begin at a variety of testosterone concentrations with many outcome measures remaining stable until testosterone levels are well below the stated normal ranges. In light of this variation, novel approaches for establishing the normal range for testosterone are needed., (© Endocrine Society 2020. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Context: Discontinuation of denosumab leads to a rapid reversal of its therapeutic effect. However, there are no data regarding how unintended delays or missed injections of denosumab impact bone mineral density (BMD) response., Objective: We examined the association of delays in injections of denosumab with BMD change., Design: We used electronic medical records from two academic hospitals from 2010 to 2017., Participants: Patients older than 45 years of age and used at least 2 doses of 60 mg denosumab. Denosumab adherence was evaluated by the medication coverage ratio (MCR). Good adherence corresponds to a dosing interval ≤7 months (defined by MCR ≥93%), moderate adherence corresponds to an interval of 7 to 10 months (MCR 75%-93%), and poor adherence corresponds to an interval ≥10 months (MCR ≤75%)., Outcome Measures: Annualized percent BMD change from baseline at the lumbar spine, total hip, and femoral neck., Results: We identified 938 denosumab injections among 151 patients; the mean (SD) age was 69 (10) years, and 95% were female. Patients with good adherence had an annualized BMD increase of 3.9% at the lumbar spine, compared with patients with moderate (3.0%) or poor adherence (1.4%, P for trend .002). Patients with good adherence had an annualized BMD increase of 2.1% at the total hip, compared with patients with moderate (1.3%) or poor adherence (0.6%, P for trend .002)., Conclusions: A longer interval between denosumab injections is associated with suboptimal BMD response at both spine and total hip. Strategies to improve the timely administration of denosumab in real-world settings are needed., (© Endocrine Society 2020. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Context: In the Denosumab and High-Dose Teriparatide Administration (DATA-HD) study, we reported that 15 months of combined high-dose (HD) teriparatide and denosumab increased mean areal bone mineral density (aBMD) at the hip and spine more than combined denosumab and standard-dose (SD) teriparatide., Objective: In the current analysis, we compare the individual rates of aBMD response between the treatment groups., Design: Single-site, open-label, randomized controlled trial in which postmenopausal women received either teriparatide 20-μg daily (SD) or 40-μg daily (HD) given months 0 through 9, overlapped with denosumab 60 mg, given months 3 through 15 (15 months' total duration). The proportion of participants in the SD and HD groups experiencing total hip, femoral neck, and lumbar spine aBMD gains of >3%, >6%, and >9% were compared., Participants: Postmenopausal women with osteoporosis completing all study visits (n = 60)., Main Outcome Measure(s): aBMD (dual x-ray absorptiometry)., Results: At the end of the 15-month treatment period, a higher proportion of women in the HD group had aBMD increases >3% (83% vs. 58%, P = .037) and >6% (45% vs. 19%, P = .034) at the total hip, and >3% at the femoral neck (86% vs. 63%, P = .044). At the lumbar spine, >3% response rates were similar, whereas the >6% and >9% response rates were greater in the HD group (100% vs. 79%, P = .012 and 93% vs. 59%, P = .003, respectively)., Conclusion: Compared with the SD regimen, more women treated with the HD regimen achieved clinically meaningful and rapid gains in hip and spine aBMD. These results suggest that this approach may provide unique benefits in the treatment of postmenopausal osteoporosis., (© Endocrine Society 2019. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Context: The ACTIVE study demonstrated the antifracture efficacy of abaloparatide in postmenopausal women with osteoporosis. ACTIVExtend demonstrated sustained fracture risk reduction with alendronate in abaloparatide-treated participants from ACTIVE. A direct comparison of the efficacy of abaloparatide and antiresorptive therapies has not been performed., Objective: The objective of this analysis is to compare the antifracture efficacy of abaloparatide in ACTIVE with that of alendronate in ACTIVExtend., Design: In this post hoc analysis, the rate of new vertebral fractures for women in ACTIVExtend (N = 1139) was calculated based on baseline and endpoint radiographs for placebo or abaloparatide in ACTIVE and alendronate in ACTIVExtend. Vertebral fracture rates between abaloparatide and alendronate were compared in a Poisson regression model. Fracture rates for nonvertebral and clinical fractures were compared based on a Poisson model during 18 months of abaloparatide or placebo treatment in ACTIVE and 18 months of alendronate treatment in ACTIVExtend., Results: The vertebral fracture rate was lower during abaloparatide treatment in ACTIVE (0.47 fractures/100 patient-years) than alendronate treatment in ACTIVExtend (1.66 fractures/100 patient-years) (relative risk reduction 71%; P = .027). Although the comparisons did not meet statistical significance, after switching from placebo (ACTIVE) to alendronate (ACTIVExtend), the rate of new vertebral fractures decreased from 2.49 to 1.66 fractures per 100 patient-years, and after switching from abaloparatide to alendronate from 0.47 to 0.19 fractures per 100 patient-years. The rates of nonvertebral fractures and clinical fractures were not significantly different., Conclusion: Initial treatment with abaloparatide may result in greater vertebral fracture reduction compared with alendronate in postmenopausal women with osteoporosis., (© Endocrine Society 2019.)

In the randomized, placebo-controlled, double-blind phase 3 ACTIVE study (NCT01343004), 18 months of abaloparatide 80 μg daily (subcutaneous injection) in postmenopausal women at risk of osteoporotic fracture significantly reduced the risk of vertebral, nonvertebral, clinical, and major osteoporotic fractures and significantly increased bone mineral density (BMD) versus placebo regardless of baseline risk factors. Women from the abaloparatide and placebo groups who completed ACTIVE were eligible for ACTIVExtend (NCT01657162), in which all enrollees received sequential, open-label monotherapy with alendronate 70 mg once weekly for up to 24 months. This prespecified analysis evaluated whether fracture risk reductions and bone mineral density (BMD) gains associated with abaloparatide during ACTIVE persisted through the full 43-month ACTIVE-ACTIVExtend study period in nine prespecified baseline risk subgroups. Baseline risk subgroups included BMD T-score at the lumbar spine, total hip, and femoral neck (≤ - 2.5 versus > - 2.5 and ≤ -3.0 versus > - 3.0), history of nonvertebral fracture (yes/no), prevalent vertebral fracture (yes/no), and age (<65 versus 65 to <75 versus ≥75 years). Forest plots display treatment effect. Treatment-by-subgroup interactions were tested using the Breslow-Day test, Cox proportional hazards model, and ANCOVA model. After the combined ACTIVE-ACTIVExtend study period, reductions in relative risk for new vertebral, nonvertebral, clinical, and major osteoporotic fractures were greater among patients in the abaloparatide/alendronate group than among those in the placebo/alendronate group across all nine baseline risk subgroups. BMD gains at the lumbar spine, total hip, and femoral neck were greater in the abaloparatide/alendronate group versus the placebo/alendronate group. No clinically meaningful interaction between treatment assignment and any baseline risk variable was observed. The sequence of abaloparatide for 18 months followed by alendronate for up to 24 months appears to be an effective treatment option for a wide range of postmenopausal women at risk for osteoporotic fractures. © 2019 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals, Inc., (© 2019 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals, Inc.)

Context: Teriparatide and denosumab are effective treatments for osteoporosis and typically reserved as second-line options after patients have used bisphosphonates. However, limited head-to-head comparative effectiveness data exist between teriparatide and denosumab., Objective: We compared changes in bone mineral density (BMD) between groups treated with teriparatide or denosumab after using bisphosphonates, focusing on the change in BMD while on either drug over 2 years., Design: Observational cohort study using electronic medical records from two academic medical centers in the United States., Participants: The study population included osteoporotic patients >45 years who received bisphosphonates >1 year before switching to teriparatide or denosumab., Outcome Measures: Annualized BMD change from baseline at the lumbar spine, total hip, and femoral neck., Results: Patients treated with teriparatide (n = 110) were compared with those treated with denosumab (n = 105); the mean (SD) age was 70 (10) years and median duration (interquartile range) of bisphosphonate use was 7.0 (5.6 to 9.7) years. Compared with denosumab users, teriparatide users had higher annualized BMD change at the spine by 1.3% (95% CI 0.02, 2.7%) but lower at the total hip by -2.2% (95% CI -2.9 to -1.5%) and the femoral neck by -1.1% (95% CI -2.1 to -0.1%). Those who switched to teriparatide had a transient loss of hip BMD for the first year, with no overall increase in the total hip BMD over 2 years., Conclusions: Among patients who use long-term bisphosphonates, the decision of switching to teriparatide should be made with caution, especially for patients at high risk of hip fracture., (Copyright © 2019 Endocrine Society.)

Background: In the Denosumab and Teriparatide Administration (DATA) study, we showed that denosumab fully inhibits teriparatide-induced bone resorption while allowing for continued teriparatide-induced bone formation, resulting in larger increases in hip and spine bone mineral density (BMD) than with either drug alone. We aimed to assess whether administration of denosumab with high dose teriparatide would stimulate larger increases in bone mass than those observed in the DATA study., Methods: DATA-HD was an open-label, randomised, controlled phase 4 trial done at Massachusetts General Hospital. Eligible women were postmenopausal women (at least 36 months since last menses or since hysterectomy with a follicle-stimulating hormone concentration of ≥40 U/L) with osteoporosis. Participants were randomly assigned (1:1) to receive teriparatide 20 μg (standard dose) or 40 μg (high dose) daily via subcutaneous injection for 9 months. At 3 months, both groups were started on denosumab 60 mg every 6 months via subcutaneous injection for 12 months. Areal BMD (aBMD) was measured at 0, 3, 9, and 15 months. Treatment was given open label, but outcome assessors were masked. The primary endpoint was percentage change from baseline in spine areal BMD (aBMD) at 15 months. Women who completed at least one study visit after baseline were included in the modified intention-to-treat analysis. Safety was assessed in all randomly assigned participants. This study is registered with ClinicalTrials.gov, number NCT02176382., Findings: Between Oct 15, 2014, and June 10, 2016, 269 women were assessed for eligibility. 76 participants were randomly assigned to 20 μg teriparatide (n=39) or 40 μg teriparatide (n=37), of whom 69 completed at least one post-baseline visit. At 15 months, mean spine aBMD had increased to a significantly greater extent in the 40 μg group (17·5% [SD 6·0] increase) than the 20 μg group (9·5% [3·2]; difference 8·1%, 95% CI 5·5 to 10·6, p<0·0001). Mean femoral neck aBMD had also increased to a greater extent in the 40 μg group (6·8% [SD 4·1] increase) than the 20 μg group (4·3% [3·7]; difference 2·5%, 0·5 to 4·5, p=0·04), as did mean total hip aBMD (40 μg group, 6·1% [3·4] increase; 20 μg group, 3·9% [2·9] increase; difference 2·2%, 0·6 to 3·8, p<0·0001). 30 (77%) of 39 participants in the 20 μg group and 29 (78%) of 37 participants in the 40 μg group had an adverse event, and seven (18%) and two (5%) patients had serious adverse events. The most frequent adverse events were joint pain (15 [38%]), muscle cramp (15 [38%]), and fatigue (12 [31%]) in the 20 μg group group and fatigue (14 [38%]), nausea (16 [43%]), and joint pain (17 [46%]) in the 40 μg group. No deaths were reported., Interpretation: Combined treatment with teriparatide 40 μg and denosumab increases spine and hip BMD more than standard combination therapy. This large and rapid increase in bone mass suggest that this high dose regimen might provide a method of restoring skeletal integrity in patients with osteoporosis., Funding: National Institutes of Health and the Dart Foundation., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

The public health implications of osteoporosis are enormous but the disease remains underdiagnosed and undertreated. In October 2018, the National Institutes of Health (NIH) convened a Pathways to Prevention (P2P) Workshop entitled "Appropriate Use of Drug Therapies for Osteoporotic Fracture Prevention" designed to identify research gaps, suggest future research opportunities, and advance the field through an evidence-based assessment. By design, the P2P report focused on "gaps" in our knowledge base. Unfortunately, however, the report did not sufficiently acknowledge the current evidence that unequivocally demonstrates the therapeutic efficacy of existing pharmacologic therapies for osteoporosis, which has the potential to exacerbate the current crises in osteoporosis diagnosis and treatment. © 2019 American Society for Bone and Mineral Research., (© 2019 American Society for Bone and Mineral Research.)

Context: It is uncertain which osteoporosis therapy is more effective: bisphosphonates or denosumab., Objective: To determine whether denosumab therapy increases bone mineral density (BMD) and reduces fracture risk more so than bisphosphonates in patients with low BMD or osteoporosis., Methods: The PubMed, Embase, and the Cochrane Library databases were searched through November 2018 for head-to-head, randomized, controlled trials comparing denosumab and bisphosphonates among adult patients with low BMD or osteoporosis. Random-effects models were used., Results: We identified 10 eligible trials including 5361 participants. Denosumab increased BMD more than bisphosphonate at 12 months (mean difference, 1.42%; 95% CI, 0.95% to 1.89%; P < 0.001) at lumbar spine, 1.11% (95% CI, 0.91% to 1.30%; P < 0.001) at total hip, and 1.00% (95% CI, 0.78% to 1.22%; P < 0.001) at femoral neck. At 24 months, the respective increase differences were 1.74% (95% CI, 1.05% to 2.43%; P < 0.001), 1.22% (95% CI, 0.66% to 1.77%; P < 0.001), and 1.19% (95% CI, 0.65% to 1.72%; P < 0.001). There was no difference in fracture end point at 12 months, but denosumab had a lower osteoporotic fracture incidence than alendronate at 24 months (risk ratio, 0.51; 95% CI, 0.27 to 0.97)., Conclusion: Denosumab improved BMD significantly more than bisphosphonate treatment at the lumbar spine, total hip, and femoral neck at 12 and 24 months. Only one study demonstrated greater osteoporotic fracture reduction with denosumab treatment. Longitudinal studies with longer follow-up and large sample size are needed to confirm the efficacy difference., (Copyright © 2019 Endocrine Society.)

Intervals between dual-energy X-ray absorptiometry (DXA) scans were evaluated in a large cohort of typical clinical practice. Intensive DXA scanning (intervals < 23 months) decreased substantially, from 16.7% in 2006 to 6.7% in 2015., Introduction: Serial dual-energy X-ray absorptiometry (DXA) measurements are suggested for patients at high risk of fractures. However, little is known about how often DXA testing occurs in clinical practice., Methods: We examined time intervals between DXA testing for monitoring purpose at two academic medical centers in the US between 2004 and 2017. The primary outcome was the presence of testing intervals < 23 months (termed "intensive DXA testing"). A generalized linear mixed model was used to evaluate the association between selected patient-level clinical factors and intensive DXA testing., Results: Forty-nine thousand four hundred ninety-four DXA tests from 20,200 patients were analyzed. The mean time interval between scans was 36 ± 21 months. Only 11.1% of the repeated DXA testing met the criterion for intensive testing. The percentage of intensive DXA testing dropped from 16.7% in 2006 to 6.7% in 2015 (p for trend < 0.001). After adjusting for age, gender, number of outpatient visits, and calendar year, correlates of intensive DXA testing included a baseline T-score < -2.5 at any anatomic site (OR, 4.8; 95%CI, 4.0-5.7), active use of drugs for osteoporosis (OR, 1.6; 95%CI, 1.3-1.9), and active use of glucocorticoids (OR, 1.3; 95%CI, 1.2-1.4)., Conclusions: The predictors of intensive DXA testing suggest that this practice is used preferentially in patients with multiple risk factors and to monitor the response to pharmacotherapy. However, intensive DXA testing has become less common in real-world clinical practice over the last decade. Further studies are required to better define the optimal use of bone mineral density testing in this vulnerable population.

As osteoporosis therapy options have expanded, and clinical guidelines have begun to embrace the concept of limited treatment courses and "drug holidays," the choices that physicians must make when initiating, electing to continue, or switching therapies have become more complex. As a result, one of the fundamental issues that must be carefully considered is whether, when, and in what sequence anabolic therapies should be utilized. This review evaluates the current evidence supporting the optimal sequence for the use of anabolic and antiresorptive drugs and assesses the expanding number of clinical trials favoring the initial use of anabolic therapy followed by an antiresorptive agent. This review also explores the evidence suggesting that the effectiveness of anabolic medications are diminished when used in patients that have been previously treated with specific antiresorptive drugs for prolonged periods. Finally, the recent advances in designing combination antiresorptive/anabolic treatment approaches are detailed, with a focus on combined denosumab/teriparatide regimens, which appear to provide the most substantial and clinically relevant skeletal benefits to patients with established osteoporosis. © 2018 The Authors. JBMR Plus is published by Wiley Periodicals, Inc. on behalf of the American Society for Bone and Mineral Research.

In a phase 2 trial of 222 postmenopausal women with osteoporosis aged 55 to 85 years randomized to one of three different doses of abaloparatide-SC, subcutaneous teriparatide, or placebo for 24 weeks, abaloparatide-SC resulted in improvements in skeletal microarchitecture as measured by the trabecular bone score., Introduction: Subcutaneous abaloparatide (abaloparatide-SC) increases total hip and lumbar spine bone mineral density and reduces vertebral and non-vertebral fractures. In this study, we analyzed the extent to which abaloparatide-SC improves skeletal microarchitecture, assessed indirectly by trabecular bone score (TBS)., Methods: This is a post hoc analysis of a phase 2 trial of 222 postmenopausal women with osteoporosis aged 55 to 85 years randomized to abaloparatide-SC (20, 40, or 80 μg), subcutaneous teriparatide (20 μg), or placebo for 24 weeks. TBS was measured from lumbar spine dual X-ray absorptiometry (DXA) images in 138 women for whom the DXA device was TBS software compatible. Assessments were made at baseline, 12 and 24 weeks. Between-group differences were assessed by generalized estimating equations adjusted for relevant baseline characteristics, and a pre-determined least significant change analysis was performed., Results: After 24 weeks, TBS increased significantly by 2.27, 3.14, and 4.21% versus baseline in participants on 20, 40, and 80 μg abaloparatide-SC daily, respectively, and by 2.21% in those on teriparatide (p < 0.05 for each). The TBS in the placebo group declined by 1.08%. The TBS increase in each treatment group was significantly higher than placebo at 24 weeks (p < 0.0001 for each) after adjustment for age, BMI, and baseline TBS. A dose-response was observed at 24 weeks across the three doses of abaloparatide-SC and placebo (p = 0.02). The increase in TBS in the abaloparatide-SC 80 μg group was significantly greater than TPTD (p < 0.03)., Conclusions: These results are consistent with an effect of abaloparatide-SC to improve lumbar spine skeletal microarchitecture, as assessed by TBS.

In postmenopausal women, 2 yr of combined teriparatide and denosumab increases bone mineral density more than either drug alone, and switching from either combination or teriparatide to denosumab for an additional 2 yr further increases bone mineral density. Conversely, switching from denosumab to teriparatide results in transient bone loss. The effects of these interventions on spine microarchitecture are unknown. In the DATA and DATA-Switch studies, 94 postmenopausal osteoporotic women were randomized to receive 24 mo of teriparatide (20 µg daily), denosumab (60 mg every 6 mo), or both. Then, women originally assigned to 24 mo of teriparatide received 24 mo of denosumab, whereas subjects originally randomized to 24 mo of denosumab received 24 mo of teriparatide. Subjects who received both drugs received an additional 24 mo of denosumab alone. Spine trabecular bone score (TBS, a gray-level textural assessment of bone microarchitecture) was measured blinded from treatment groups using images from 2-dimensional dual-energy X-ray absorptiometry spine scans at 0, 12, 24, 30, 36, and 48 mo in 65 women who had posterior-anterior spine dual-energy X-ray absorptiometry images suitable for TBS analysis. After 24 mo, TBS increased by 2.7 ± 4.7% in the teriparatide group (p = 0.009 vs baseline), by 1.8 ± 5.0% in the denosumab group (p = 0.118 vs baseline), and by 4.5 ± 6.7% in the combination group (p = 0.017 vs baseline), with no significant between-group differences. In the 6 mo after the treatments were switched (months 24-30), TBS continued to increase in the combination-to-denosumab and teriparatide-to-denosumab groups but decreased by -1.1 ± 4.0% in the denosumab-to-teriparatide group (p < 0.05 vs other groups). After 48 mo, compared to month 0, TBS increased by 5.1 ± 5.8% in the teriparatide-to-denosumab group, by 3.6 ± 4.2% in the denosumab-to-teriparatide group, and by 6.1 ± 4.7% in the combination-to-denosumab group (p < 0.001 vs baseline for all groups, p = not significant for between-group differences). Switching from teriparatide to denosumab also increased spine TBS. Conversely, switching from denosumab to teriparatide transiently degraded spine trabecular microarchitecture, the clinical consequences of which require further study., (Copyright © 2017 The International Society for Clinical Densitometry. Published by Elsevier Inc. All rights reserved.)

In postmenopausal osteoporosis, switching from teriparatide to denosumab results in continued bone mineral density (BMD) gains whereas switching from denosumab to teriparatide results in BMD loss. To assess the effects of these transitions on bone microarchitecture and strength, we performed high-resolution peripheral QCT (HR-pQCT) at the distal tibia and radius in postmenopausal osteoporotic women who received 24 months of teriparatide 20 μg daily followed by 24 months of denosumab 60 mg every 6 months, 24 months of denosumab followed by 24 months of teriparatide, or 24 months of both medications followed by 24 months of denosumab. The 77 women who completed at least one post-switch visit are included in this analysis. Tibial cortical volumetric BMD (vBMD) increased between months 24 and 48 in the teriparatide-to-denosumab (net 48-month change -0.8% ± 2.4%) and combination-to-denosumab groups (net 48-month changes +2.4% ± 4.1%) but decreased in the denosumab-to-teriparatide group (net 48-month change -3.4% ± 3.2%, p < 0.001 for all between-group comparisons). Changes in total vBMD, cortical thickness, and estimated stiffness (by micro-finite element analysis [µFEA]) followed a similar pattern, as did changes at the radius. Conversely, tibial cortical porosity remained stable between months 24 and 48 in the teriparatide-to-denosumab and combination-to-denosumab groups (net 48-month changes +7.2% ± 14.8% and -3.4% ± 12.1%, respectively) but increased in the denosumab-to-teriparatide group (net 48-month change +16.2% ± 11.5%, p < 0.05 versus other groups). Trabecular vBMD changes did not differ among groups. Together, these findings demonstrate that in women treated with denosumab, switching to teriparatide is associated with a reduction in total and cortical vBMD, cortical thickness, and estimated strength, whereas switching to denosumab from teriparatide or combination therapy results in improvements in these parameters with the greatest improvements observed in women treated with combined therapy followed by denosumab. These findings strongly suggest that the use of teriparatide after denosumab should be avoided and that the use of combined teriparatide/denosumab followed by denosumab alone may be a useful treatment strategy in those with severe osteoporosis. © 2017 American Society for Bone and Mineral Research., (© 2017 American Society for Bone and Mineral Research.)

When teriparatide and denosumab are discontinued, bone mineral density (BMD) abruptly decreases. To compare rates of bone loss in postmenopausal women who discontinue denosumab or teriparatide and receive no additional prescription osteoporosis medications to women who discontinue these drugs followed by prompt antiresorptive therapy, we asked women concluding the Denosumab and Teriparatide Administration (DATA) study and its extension, DATA-Switch, to return for BMD measurements 1-2years after study completion. In these studies, women received 2-years of either teriparatide, denosumab or both medications followed by 2-years of the alternate therapy (women who received combination therapy initially received an additional 2-years of denosumab alone). Fifty of 69 women who completed DATA-Switch returned after a mean of 15.4±3.5months. Of the 28 women who received antiresorptive therapy (10 denosumab, 10 oral bisphosphonates, 8 intravenous zoledronic acid), the mean interval between ending DATA-Switch and beginning antiresorptive therapy was 3.8±3.1months. In the 22 women not receiving follow-up therapy, femoral neck, total hip, and spine BMD decreased by -4.2±4.3%, -4.5±3.6%, and -10.0±5.4%, respectively, while BMD was maintained in those who did receive follow-up antiresorptive drugs (femoral neck, total hip, and spine BMD changes of -0.6±2.7%, -0.8±3.1%, and -1.2±4.7%, respectively, P<0.001 for all between-group comparisons). Among untreated women, femoral neck BMD decreased more in those discontinuing denosumab (-5.8±4.0%) than in those discontinuing teriparatide (-0.8±2.6%, P=0.008). Total hip BMD, but not spine BMD, showed a similar pattern. Among treated women, denosumab increased femoral neck and total hip BMD more than bisphosphonates while BMD changes at the spine did not differ significantly. In summary, the large teriparatide and denosumab-induced gains in BMD achieved with 4years of intensive therapy in the DATA and DATA-Switch studies were maintained in patients who received prompt antiresorptive therapy but not in those left untreated. These results demonstrate the negative consequences of delaying consolidation therapy in women treated with these drugs and underscore the importance of timely medication transitions in such patients., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Purpose of Review: The purpose is to review the efficacy and optimal use of parathyroid hormone and parathyroid hormone-related protein analogs in osteoporosis treatment., Recent Findings: The parathyroid hormone analog teriparatide, a potent stimulator of bone remodeling, increases hip and spine bone mineral density and reduces the risk of vertebral and non-vertebral fractures in postmenopausal osteoporotic women. The parathyroid hormone-related protein analog, abaloparatide, also reduces fracture incidence but has pharmacological effects that differ from teriparatide, particularly in cortical bone. These analogs provide maximal benefit when their use is followed by a potent antiresorptive medication. Moreover, studies have shown that the combination of teriparatide and the RANK-ligand inhibitor, denosumab, increase bone density and estimated strength more than monotherapy and more than any currently available regimen. Parathyroid hormone and parathyroid hormone-related protein analogs, whether as monotherapy, in combination with antiresorptive agents or in sequence with antiresorptive agents, will likely play an expanding role in osteoporosis management.

Both antiresorptive and anabolic osteoporosis medications increase bone mineral density (BMD), but no single agent can restore normal bone strength in most osteoporotic patients. Moreover, the magnitude and consistency of the patient response to each individual agent vary depending on the anatomic site. In the DATA study, we reported that in postmenopausal osteoporotic women, 2 years of combined denosumab and teriparatide increase mean BMD at the hip and spine more than either drug alone. In the current analysis, we wished to determine if the individual rates of BMD response were also greater among women treated with both drugs. In DATA, 94 postmenopausal osteoporotic women (ages 51-91) were randomized to receive teriparatide (20 mcg subcutaneously daily), denosumab (60 mg subcutaneously every 6 mo), or both medications for 24 mo. The BMD of the total hip (TH), femoral neck (FN), and lumbar spine (LS) were assessed by dual-energy X-ray absorptiometry. The 82 subjects who completed all 2-yr treatments were analyzed. Responders were defined as experiencing BMD increases of >3%. An "excellent response" was defined as an increase of >6%. Over 24 mo, TH BMD increased by >3% in 36%, 53%, and 92% of women in the teriparatide, denosumab, and combination groups, respectively, and by >6% in 11%, 17%, and 50% in the teriparatide, denosumab, and combination groups, respectively (p < 0.01 for all comparisons vs combination). FN response rates were similar to TH. In the LS, BMD increased by >3% in 85%, 93%, and 100% of women in the teriparatide, denosumab, and combination groups, respectively (p = nonsignificant for all comparisons) and by >6% in 63%, 78%, and 100% of women in the teriparatide, denosumab, and combination groups, respectively (combination vs teriparatide, p = 0.001; combination vs denosumab, p = 0.016). In summary, more women treated with 24 mo of combined denosumab and teriparatide achieved a significant response at the TH and FN than those treated with either drug alone. All women treated with both agents together experienced an excellent response at the LS. These results support the continued investigation of combined denosumab and teriparatide therapy in postmenopausal osteoporotic women utilizing clinical endpoints such as fracture reduction., (Copyright © 2016 International Society for Clinical Densitometry. Published by Elsevier Inc. All rights reserved.)

Context: In postmenopausal osteoporosis, combining denosumab and teriparatide increases hip and spine bone mineral density more than either monotherapy., Objective: The objective of the study was to determine the effects of 2 years of combination therapy on bone microarchitecture and estimated strength., Design: This was an open-label, randomized controlled trial., Participants and Methods: We performed high-resolution peripheral quantitative computed tomography at the distal tibia and radius in 94 postmenopausal osteoporotic women randomized to 2 years of teriparatide 20 μg sc daily, denosumab 60 mg sc every 6 months, or both., Results: Total volumetric bone mineral density (vBMD) at the radius and tibia, trabecular vBMD at the radius, and cortical vBMD at the tibia all increased more in the combination group than both monotherapy groups (P < .002 for all comparisons with combination). Cortical thickness at the tibia also increased more in the combination group (8.1% ± 4.3%) than both other groups (P < .001). Cortical porosity at both the radius and tibia increased progressively over the 24-month treatment period in the teriparatide group but was stable in both other groups (P < .001 teriparatide vs both other groups). Trabecular vBMD at the tibia increased similarly in all groups, whereas radius trabecular vBMD increased more in the combination group than the other groups (P < .01 for both comparisons). Finite element analysis-estimated strength improved or was maintained by all treatments at both the radius and tibia., Conclusions: Two years of combined teriparatide and denosumab improves bone microarchitecture and estimated strength more than the individual treatments, particularly in cortical bone. These findings suggest that this regimen may be beneficial in postmenopausal osteoporosis.

Background: Severe gonadal steroid deficiency induces bone loss in adult men; however, the specific roles of androgen and estrogen deficiency in hypogonadal bone loss are unclear. Additionally, the threshold levels of testosterone and estradiol that initiate bone loss are uncertain., Methods: One hundred ninety-eight healthy men, ages 20-50, received goserelin acetate, which suppresses endogenous gonadal steroid production, and were randomized to treatment with 0, 1.25, 2.5, 5, or 10 grams of testosterone gel daily for 16 weeks. An additional cohort of 202 men was randomized to receive these treatments plus anastrozole, which suppresses conversion of androgens to estrogens. Thirty-seven men served as controls and received placebos for goserelin and testosterone. Changes in bone turnover markers, bone mineral density (BMD) by dual-energy x-ray absorptiometry (DXA), and BMD by quantitative computed tomography (QCT) were assessed in all men. Bone microarchitecture was assessed in 100 men., Results: As testosterone dosage decreased, the percent change in C-telopeptide increased. These increases were considerably greater when aromatization of testosterone to estradiol was also suppressed, suggesting effects of both testosterone and estradiol deficiency. Decreases in DXA BMD were observed when aromatization was suppressed but were modest in most groups. QCT spine BMD fell substantially in all testosterone-dose groups in which aromatization was also suppressed, and this decline was independent of testosterone dose. Estradiol deficiency disrupted cortical microarchitecture at peripheral sites. Estradiol levels above 10 pg/ml and testosterone levels above 200 ng/dl were generally sufficient to prevent increases in bone resorption and decreases in BMD in men., Conclusions: Estrogens primarily regulate bone homeostasis in adult men, and testosterone and estradiol levels must decline substantially to impact the skeleton., Trial Registration: ClinicalTrials.gov, NCT00114114., Funding: AbbVie Inc., AstraZeneca Pharmaceuticals LP, NIH.

Background: Unlike most chronic diseases, osteoporosis treatments are generally limited to a single drug at a fixed dose and frequency. Nonetheless, no approved therapy is able to restore skeletal integrity in most osteoporotic patients and the long-term use of osteoporosis drugs is controversial. Thus, many patients are treated with the sequential use of two or more therapies. The DATA study showed that combined teriparatide and denosumab increased bone mineral density more than either drug alone. Discontinuing teriparatide and denosumab, however, results in rapidly declining bone mineral density. In this DATA-Switch study, we aimed to assess the changes in bone mineral density in postmenopausal osteoporotic women who transitioned between treatments., Methods: This randomised controlled trial (DATA-Switch) is a preplanned extension of the denosumab and teriparatide administration study (DATA), in which 94 postmenopausal osteoporotic women were randomly assigned to receive 24 months of teriparatide (20 mg daily), denosumab (60 mg every 6 months), or both drugs. In DATA-Switch, women originally assigned to teriparatide received denosumab (teriparatide to denosumab group), those originally assigned to denosumab received teriparatide (denosumab to teriparatide group), and those originally assigned to both received an additional 24 months of denosumab alone (combination to denosumab group). Bone mineral density at the spine, hip, and wrist were measured 6 months, 12 months, 18 months, and 24 months after the drug transitions as were biochemical markers of bone turnover. The primary endpoint was the percent change in posterior-anterior spine bone mineral density over 4 years. Between-group changes were assessed by one-way analysis of variance in our modified intention-to-treat population. This study is registered with ClinicalTrials.gov, number NCT00926380., Findings: Between Sept 27, 2011, and Jan 28, 2013, eligible women from the DATA study were enrolled into DATA-Switch. Of 83 potential enrollees from the DATA study, 77 completed at least one post-baseline visit. After 48 months, the primary outcome of mean spine bone mineral density increased by 18·3% (95% CI 14·9-21·8) in 27 women in the teriparatide to denosumab group, 14·0% (10·9-17·2) in 27 women the denosumab to teriparatide group, and 16·0% (14·0-18·0) in 23 women in the combination to denosumab group, although this increase did not differ significantly between groups (for between-group comparisons, p=0·13 for the teriparatide to denosumab group vs the denosumab to teriparatide group, p=0·30 for the teriparatide to denosumab group vs the combination to denosumab group, and p=0·41 for the denosumab to teriparatide group vs the combination to denosumab group). For the bone mineral density secondary outcomes, total hip bone mineral density increased more in the teriparatide to denosumab group (6·6% [95% CI 5·3-7·9]) than in the denosumab to teriparatide group (2·8% [1·3-4·2], p=0·0002), but had the greatest increase in the combination to denosumab group (8·6% [7·1-10·0]; p=0·0446 vs the teriparatide to denosumab group, p<0·0001 vs the denosumab to teriparatide group). Similarly, femoral neck bone mineral density increased more in the teriparatide to denosumab group (8·3% [95% CI 6·1-10·5]) and the combination to denosumab group (9·1% [6·1-12·0]) than in the denosumab to teriparatide group (4·9% [2·2-7·5]; p=0·0447 for teriparatide to denosumab vs denosumab to teriparatide, p=0·0336 for combination to denosumab vs denosumab to teriparatide). Differences between the combination to denosumab group and the teriparatide to denosumab group did not differ significantly (p=0·67). After 48 months, radius bone mineral density was unchanged in the teriparatide to denosumab group (0·0% [95% CI -1·3 to 1·4]), whereas it decreased by -1·8% (-5·0 to 1·3) in the denosumab to teriparatide group, and increased by 2·8% (1·2-4·4) in the combination to denosumab group (p=0·0075 for the teriparatide to denosumab group vs the combination to denosumab group; p=0·0099 for the denosumab to teriparatide group vs the combination to denosumab group). One participant in the denosumab to teriparatide group had nephrolithiasis, classified as being possibly related to treatment., Interpretation: In postmenopausal osteoporotic women switching from teriparatide to denosumab, bone mineral density continued to increase, whereas switching from denosumab to teriparatide results in progressive or transient bone loss. These results should be considered when choosing the initial and subsequent management of postmenopausal osteoporotic patients., Funding: Amgen, Eli Lilly, and National Institutes of Health., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Background: Epidemiologic data suggest that low serum 25-hydroxyvitamin D [25(OH)D] increases insulin resistance and the risk of type 2 diabetes. Few interventional trials have assessed the effect of vitamin D on insulin metabolism, and published results are discordant., Objective: The goal of this study was to perform a detailed assessment of the effect of ergocalciferol administration on glucose and insulin metabolism in healthy people with low total 25(OH)D(total)., Design: This was a 12-wk, double-blinded, randomized controlled trial. We enrolled 90 healthy volunteers aged 18-45 y with serum 25(OH)D ≤20 ng/mL (by immunoassay) and administered 50,000 IU ergocalciferol/wk or placebo for 12 wk. Primary endpoints were change in first-phase insulin response and insulin sensitivity as measured by intravenous glucose tolerance test. Secondary endpoints included change in homeostasis model assessment of insulin resistance; fasting glucose, insulin, and lipids; body mass index (BMI); and blood pressure., Results: On-study 25(OH)D(total) was assessed by liquid chromatography-tandem mass spectrometry. In the treated group, 25(OH)D(total) rose from 18 ± 7 to 43 ± 12 ng/mL (P < 0.001) with no change in the placebo group. Despite this increase, at 12 wk, there were no between-group differences in either insulin response or insulin sensitivity; nor were there differences in any measured secondary endpoints. There was no evidence of effect modification by sex, race, glucose tolerance status, baseline 25(OH)D(total), or BMI., Conclusion: In healthy persons with low 25(OH)D(total), ergocalciferol administration for 12 wk normalizes 25(OH)D(total) but does not improve insulin secretion, insulin sensitivity, or other markers of metabolic health., (© 2015 American Society for Nutrition.)

Context: In postmenopausal osteoporotic women, denosumab fully inhibits teriparatide-induced bone resorption at approved doses. This property of denosumab is distinct from that of alendronate and likely contributes to the efficacy of combination denosumab and teriparatide therapy. Whether denosumab fully inhibits bone resorption when challenged by a higher dose of teriparatide is unknown., Objective: We aimed to define the comparative ability of denosumab and alendronate to block the acute proresorptive effects of high-dose teriparatide., Design, Setting, and Participants: In this randomized controlled trial, bone resorption (serum C-telopeptide [CTX]) was measured in 25 postmenopausal women prior to and 4 hours after a single 40-μg sc teriparatide injection. Subjects then received either a single injection of denosumab 60 mg or oral alendronate 70 mg weekly for 8 weeks. After 8 weeks, serum CTX was again measured before and 4 hours after a teriparatide a 40-μg injection., Outcomes: The primary outcome was the between-group difference in the teriparatide-induced change in CTX from baseline to week 8., Results: At baseline, 40 μg of teriparatide induced similar 4-hour increases in mean CTX in both groups (alendronate 47% ± 14%, denosumab 46% ± 16%). After 8 weeks, teriparatide was still able to stimulate bone resorption in women treated with alendronate (mean CTX increase of 43% ± 29%) but not in women treated with denosumab (-7% ± 11%; P < .001 for between group comparison)., Conclusions: Denosumab, but not alendronate, fully inhibits the ability of high-dose teriparatide to increase bone resorption acutely. These results suggest that combining denosumab with a more potent anabolic stimulus may result in greater separation between bone resorption and formation and hence greater increases in bone mass.

Context: Abaloparatide is a novel synthetic peptide analog of parathyroid hormone-related protein (PTHrP) that is currently being developed as a potential anabolic agent in the treatment of postmenopausal osteoporosis., Objective: This study sought to assess the effects of abaloparatide on bone mineral density (BMD) at the lumbar spine, total hip, and femoral neck in postmenopausal women with osteoporosis., Design: Multi-center, multi-national, double-blind placebo controlled trial in which postmenopausal women were randomly assigned to receive 24 weeks of treatment with daily sc injections of placebo, abaloparatide, 20, 40, or 80 μg, or teriparatide, 20 μg. A 24-week extension was also performed in a subset of subjects., Participants: Postmenopausal women with osteoporosis (n = 222)., Main Outcome Measures: BMD by dual-x-ray absorptiometry and biochemical markers of bone turnover., Results: At 24 weeks, lumbar spine BMD increased by 2.9, 5.2, and 6.7% in the abaloparatide, 20-, 40-, and 80-μg groups, respectively, and 5.5% in the teriparatide group. The increases in the 40- and 80-μg abaloparatide groups and the teriparatide group were significantly greater than placebo (1.6%). Femoral neck BMD increased by 2.7, 2.2, and 3.1% in abaloparatide, 20-, 40-, and 80-μg groups, respectively, and 1.1% in the teriparatide group. The increase in femoral neck BMD with abaloparatide, 80 μg was significantly greater than placebo (0.8%). Total hip BMD increased by 1.4, 2.0, and 2.6% in the abaloparatide, 20-, 40-, and 80-μg groups, respectively. The total hip increases in the 40- and 80-μg abaloparatide groups were greater than both placebo (0.4%) and teriparatide (0.5%)., Conclusions: Compared with placebo, 24 weeks of daily sc abaloparatide increases BMD of the lumbar spine, femoral neck, and total hip in a dose-dependent fashion. Moreover, the abaloparatide-induced BMD increases at the total hip are greater than with the marketed dose of teriparatide. These results support the further investigation of abaloparatide as an anabolic therapy in postmenopausal osteoporosis.

Combined teriparatide and denosumab increases spine and hip bone mineral density more than either drug alone. The effect of this combination on skeletal microstructure and microarchitecture, however, is unknown. Because skeletal microstructure and microarchitecture are important components of skeletal integrity, we performed high-resolution peripheral quantitative computed tomography (HR-pQCT) assessments at the distal tibia and radius in postmenopausal osteoporotic women randomized to receive teriparatide 20 µg daily (n = 31), denosumab 60 mg every 6 months (n = 33), or both (n = 30) for 12 months. In the teriparatide group, total volumetric bone mineral density (vBMD) did not change at either anatomic site but increased in both other groups at both sites. The increase in vBMD at the tibia was greater in the combination group (3.1 ± 2.2%) than both the denosumab (2.2 ± 1.9%) and teriparatide groups (-0.3 ± 1.9%) (p < 0.02 for both comparisons). Cortical vBMD decreased by 1.6 ± 1.9% at the tibia and by 0.9 ± 2.8% at the radius in the teriparatide group, whereas it increased in both other groups at both sites. Tibia cortical vBMD increased more in the combination group (1.5 ± 1.5%) than both monotherapy groups (p < 0.04 for both comparisons). Cortical thickness did not change in the teriparatide group but increased in both other groups. The increase in cortical thickness at the tibia was greater in the combination group (5.4 ± 3.9%) than both monotherapy groups (p < 0.01 for both comparisons). In the teriparatide group, radial cortical porosity increased by 20.9 ± 37.6% and by 5.6 ± 9.9% at the tibia but did not change in the other two groups. Bone stiffness and failure load, as estimated by finite element analysis, did not change in the teriparatide group but increased in the other two groups at both sites. Together, these findings suggest that the use of denosumab and teriparatide in combination improves HR-pQCT measures of bone quality more than either drug alone and may be of significant clinical benefit in the treatment of postmenopausal osteoporosis., (© 2014 American Society for Bone and Mineral Research.)