A Longitudinal Study of Skeletal Histomorphometry at 6 and 24 Months Across Four Bone Envelopes in Postmenopausal Women With Osteoporosis Receiving Teriparatide or Zoledronic Acid in the SHOTZ Trial

Exercise for optimizing bone health after hormone-induced increases in bone stiffness

Hormones and mechanical loading co-regulate bone throughout the lifespan. In this review, we posit that times of increased hormonal influence on bone provide opportunities for exercise to optimize bone strength and prevent fragility. Examples include endogenous secretion of growth hormones and sex steroids that modulate adolescent growth and exogenous administration of osteoanabolic drugs like teriparatide, which increase bone stiffness, or its resistance to external forces. We review evidence that after bone stiffness is increased due to hormonal stimuli, mechanoadaptive processes follow. Specifically, exercise provides the mechanical stimulus necessary to offset adaptive bone resorption or promote adaptive bone formation. The collective effects of both decreased bone resorption and increased bone formation optimize bone strength during youth and preserve it later in life. These theoretical constructs provide physiologic foundations for promoting exercise throughout life.

Effects of four-year cyclic versus two-year daily teriparatide treatment on volumetric bone density and bone strength in postmenopausal women with osteoporosis

PURPOSE

To evaluate the effects of cyclic vs daily teriparatide treatment (TPTD) on volumetric bone mineral density (vBMD) and bone strength at the hip and spine in women who were previously untreated.

METHODS

A total of 86 women were randomized to a 24-month open label treatment of either daily TPTD (20 μg daily) or cyclic TPTD (20 μg daily for 3 months followed by 3 months off). During a 2-year extension, women in the daily TPTD group were switched to alendronate (ALN) and those in the cyclic TPTD group continued on cyclic TPTD (without any ALN). QCT images were acquired at baseline, 2-years (n = 54) and 4-years (n = 35) and analyzed for volumetric integral, cortical and trabecular bone mineral density (vBMD) and bone strength (by finite element analysis) at the hip and spine. The primary analysis presented here compared the responses across equal total TPTD doses (2 years daily vs 4 years cyclic).

RESULTS

In the spine, integral vBMD and strength increased substantially after 2 years daily and 4 years cyclic TPTD, with no significant differences (vBMD +12 % vs +11 %, respectively, p = 0.70; spine strength +21 % vs +16 %, respectively, p = 0.35). At the hip, the gains were smaller, but again no significant differences were detected between the groups for the increases in either vBMD (+2 % in both groups, p = 0.97) or hip strength (3 % vs 3 %, p = 0.91). In the spine, the vBMD increment was about twice as large in the trabecular vs peripheral compartment; in the hip, significant vBMD gain was seen only in the trabecular compartment.

CONCLUSIONS

The gains in volumetric BMD and bone strength for an equivalent dose of TPTD did not depend on whether it was administered every day over two years or cyclically over four years.

The why and how of sequential and combination therapy in osteoporosis. A review of the current evidence

It is now well recognized that over the lifetime of a patient with osteoporosis, more than one medication will be needed to treat the disease and to decrease fracture risk. Though current gaps in osteoporosis therapy can be potentially mitigated with sequential and combination regimens, how to move seamlessly amongst the multiple treatments currently available for osteoporosis for sustained efficacy is still unclear. Data from recent studies show that an anabolic agent such as teriparatide or romosozumab followed by an antiresorptive affords maximal gain in BMD and possibly better and earlier fracture risk reduction compared to a regimen which follows the opposite sequence. Sequentially moving to a bisphosphonate such as alendronate from an anabolic agent such as abaloparatide has also been shown to preserve the fracture reduction benefits seen with the latter. This sequence of an anabolic agent followed by an antiresorptive should especially be considered in the high-risk patient with imminent fracture risk to rapidly reduce the risk of subsequent fractures. The data surrounding optimum timing of initiation of bisphosphonate therapy following denosumab discontinuation is still unclear. Though data suggests that combining a bisphosphonate with teriparatide does not provide substantial BMD gains compared to monotherapy, the concomitant administration of denosumab with teriparatide has been shown to significantly increase areal BMD as well as to increase volumetric BMD and estimated bone strength. This narrative review explores the available evidence regarding the various sequential and combination therapy approaches and the potential role they could play in better managing osteoporosis.

Treatment of postmenopausal osteoporosis patients with teriparatide for 24 months reverts forming bone quality indices to premenopausal healthy control values

Postmenopausal osteoporosis (PMOP) therapies are frequently evaluated by bone mineral density (BMD) gains against patients receiving placebo (calcium and vitamin D supplementation, a mild bone turnover-suppressing intervention), which is not equivalent to either healthy or treatment-naive PMOP. The aim of the present observational study was to assess the effects of TPTD treatment in PMOP (20 μg, once daily) at 6 (TPTD 6m; n = 28, age 65 ± 7.3 years), and 24 (TPTD 24m; n = 32, age 67.4 ± 6.15 years) months on bone quality indices at actively forming trabecular surfaces (with fluorescent double labels). Data from the TPTD-treated PMOP patients were compared with those in healthy adult premenopausal women (HC; n = 62, age 40.5 ± 10.6 years), and PMOP receiving placebo (PMOP-PLC; n = 94, age 70.6 ± 4.5 years). Iliac crest biopsies were analyzed by Raman microspectroscopy at three distinct tissue ages: mid-distance between the second label and the bone surface, mid-distance between the two labels, and 1 μm behind the first label. Mineral to matrix ratio (MM), mineral maturity/crystallinity (MMC), tissue water (TW), glycosaminoglycan (GAGs), and pyridinoline (Pyd) content were determined. Outcomes were compared by ANCOVA with subject age and tissue age as covariates, and health status as a fixed factor, followed by Sidak's post-hoc testing (significance assigned to p < 0.05). Both TPTD groups increased MM compared to PMOP-PLC. While TPTD 6m had values similar to HC, TPTD 24m had higher values compared to either HC or TPTD 6m. Both TPTD groups had lower MMC values compared to PMOP-PLC and similar to HC. TPTD 6m patients had higher TW content compared to HC, while TPTD 24m had values similar to HC and lower than either PMOP-PLC or TPTD 6m. Both TPTD groups had lower GAG content compared to HC group, while TPTD 6m had higher values compared to PMOP-PLC. Finally, TPTD 6m patients had higher Pyd content compared to HC and lower compared to PMOP-PLC, while TPTD 24m had lower values compared to PMOP-PLC and TPTD 6m, and similar to HC group. The results of the present study indicate that effects of TPTD on forming trabecular bone quality indices depend on treatment duration. At the recommended length of 24 m, TPTD restores bone mineral and organic matrix quality indices (MMC, TW, Pyd content) to premenopausal healthy (HC) levels.

Treatment Consideration in Postmenopausal Osteoporosis Patients at Imminent Fracture Risk

Osteoporosis is the most common metabolic bone disease and constitutes a major public health problem all over the world. Most international clinical practice guidelines have conventionally positioned the class of antiresorptive drugs, the bisphosphonates, as the first-line medical therapy for the management of postmenopausal osteoporosis. With the clinical development of more potent antiresorptive drugs as well as bone-forming drugs, more therapeutic options with different mechanisms of action, therapeutic efficacies, and adverse effect profiles are currently available. Bone-forming drugs have demonstrated a faster and better protection to patients with osteoporosis such that clinical management decisions should position their prioritized use in patients with a very high fracture risk. This article provides a review on the preferential selection of bone-forming drugs for management of postmenopausal osteoporosis in patients with imminent fracture risk.

Efficacy of Zoledronic Acid in the Treatment of Nonmalignant Painful Bone Marrow Lesions: A Triple-Blind, Randomized, Placebo-Controlled Phase III Clinical Trial (ZoMARS)

Bone marrow lesions (BML) represent areas of deteriorated bone structure and metabolism characterized by pronounced water-equivalent signaling within the trabecular bone on magnetic resonance imaging (MRI). BML are associated with repair mechanisms subsequent to various clinical conditions associated with inflammatory and non-inflammatory injury to the bone. There is no approved treatment for this condition. Bisphosphonates are known to improve bone stability in osteoporosis and other bone disorders and have been used off-label to treat BML. A randomized, triple-blind, placebo-controlled phase III trial was conducted to assess efficacy and safety of single-dose zoledronic acid (ZOL) 5 mg iv with vitamin D 1000 IU/d as opposed to placebo with vitamin D 1000 IU/d in 48 patients (randomized 2:1) with BML. Primary efficacy endpoint was reduction of edema volume 6 weeks after treatment as assessed by MRI. After treatment, mean BML volume decreased by 64.53% (±41.92%) in patients receiving zoledronic acid and increased by 14.43% (±150.46%) in the placebo group (p = 0.007). A decrease in BML volume was observed in 76.5% of patients receiving ZOL and in 50% of the patients receiving placebo. Pain level (visual analogue scale [VAS]) and all categories of the pain disability index (PDI) improved with ZOL versus placebo after 6 weeks but reconciled after 6 additional weeks of follow-up. Six serious adverse events occurred in 5 patients, none of which were classified as related to the study drug. No cases of osteonecrosis or fractures occurred. Therefore, single-dose zoledronic acid 5 mg iv together with vitamin D may enhance resolution of bone marrow lesions over 6 weeks along with reduction of pain compared with vitamin D supplementation only. © 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).

T-Cell Mediated Inflammation in Postmenopausal Osteoporosis

Osteoporosis is the most prevalent metabolic bone disease that affects half the women in the sixth and seventh decade of life. Osteoporosis is characterized by uncoupled bone resorption that leads to low bone mass, compromised microarchitecture and structural deterioration that increases the likelihood of fracture with minimal trauma, known as fragility fractures. Several factors contribute to osteoporosis in men and women. In women, menopause - the cessation of ovarian function, is one of the leading causes of primary osteoporosis. Over the past three decades there has been growing appreciation that the adaptive immune system plays a fundamental role in the development of postmenopausal osteoporosis, both in humans and in mouse models. In this review, we highlight recent data on the interactions between T cells and the skeletal system in the context of postmenopausal osteoporosis. Finally, we review recent studies on the interventions to ameliorate osteoporosis.

Anabolic Agents for Postmenopausal Osteoporosis: How Do You Choose?

PURPOSE OF REVIEW

There are now three anabolic agents available for the treatment of postmenopausal women at high risk for fracture. The purpose of this review is to supply a rationale to aid in determining which agent should be used in which clinical settings.

RECENT FINDINGS

Studies over the last decade have shown that anabolic agents produce faster and larger effects against fracture than antiresorptive agents. Furthermore, trials evaluating anabolic antiresorptive treatment sequences have shown that anabolic first treatment strategies produce the greatest benefits to bone density, particularly in the hip region. However, there are no head-to-head evaluations of the three anabolic therapies with fracture outcomes or bone density, and these studies are not likely to occur. How to decide which agent to use at which time in a woman's life is unknown. We review the most significant clinical trials of anabolic agents which have assessed fracture, areal or volumetric bone density, microarchitecture, and/or bone strength, as well as information gleaned from histomorphometry studies to provide a rationale for consideration of one agent vs another in various clinical settings. There is no definitive answer to this question; all three agents increase bone strength and reduce fracture risk rapidly. Since the postmenopausal lifespan could be as long as 40-50 years, it is likely that very high-risk women will utilize different anabolic agents at different points in their lives.

Mineral and organic matrix composition at bone forming surfaces in postmenopausal women with osteoporosis treated with either teriparatide or zoledronic acid

The ability of bone to resist fracture is dependent on the composite nature of its mineral and organic matrix content. Teriparatide (TPTD) and zoledronic acid (ZOL) are approved anabolic and antiresorptive therapies, respectively, to reduce fracture risk in women with postmenopausal osteoporosis. In the SHOTZ study, postmenopausal women with osteoporosis were treated with TPTD (20 μg daily, subcutaneous) or ZOL (5 mg/year, intravenous infusion) for 24 months. Iliac crest biopsies were obtained at 6 months and again at 24 months from approximately one third of the original study cohort. To investigate the early effects of these two drugs on the quality of newly formed bone, we used vibrational spectroscopic techniques to analyze tetracycline-labelled transiliac biopsies obtained from participants at the 6-month time point. Raman spectra were acquired at forming trabecular and intra-cortical surfaces (identified by fluorescent double labels), to determine mineral, organic matrix, glycosaminoglycan, and tissue water content, as well as mineral maturity/crystallinity at three specific tissue ages (1-5, 15, and ≥25 days). Fourier transformed infrared microspectroscopy was used to determine pyridinoline/divalent collagen cross-link ratios. At 6 months, treatment with TPTD versus ZOL resulted in lower mineral and higher organic matrix content, increased tissue water content, and lower mineral/matrix, mineral maturity/crystallinity, glycosaminoglycan content, and pyridinoline/divalent enzymatic collagen cross-link ratio. Our results suggest that TPTD and ZOL have differential effects on material properties of newly formed bone at individual remodeling sites, highlighting their different mechanisms of action.

Differential effects of abaloparatide and teriparatide on hip cortical volumetric BMD by DXA-based 3D modeling

In postmenopausal osteoporotic women in ACTIVE, abaloparatide reduced fracture risk and increased areal bone mineral density (BMD) more than teriparatide at the hip and wrist. DXA-based 3D modeling showed significantly greater increases in hip cortical volumetric BMD with abaloparatide versus teriparatide. This may explain differences reported in aBMD by DXA.

INTRODUCTION

In ACTIVE, abaloparatide (ABL) increased bone mineral density (BMD) shown by dual-energy X-ray absorptiometry (DXA) while reducing fracture incidence in postmenopausal osteoporotic women. Changes in DXA BMD with ABL, 80 μg, were significantly greater than with open-label teriparatide (TPTD), 20 μg, at cortical sites including total hip, femoral neck, and 1/3 distal radius. The purpose of this study was to better understand the relative effects of ABL and TPTD on cortical and cancellous compartments in the proximal femur.

METHODS

Hip DXA images from a subset of randomly selected patients in the ACTIVE trial (n = 250/arm) were retrospectively analyzed using three-dimensional modeling methods (3D-SHAPER software) to evaluate changes from baseline at months 6 and 18.

RESULTS

Similar significant increases in trabecular volumetric BMD (vBMD, + 9%) and cortical thickness (+ 1.5%) were observed with ABL and TPTD by 3D-DXA at 18 months. In contrast, only ABL significantly increased cortical vBMD versus baseline (+ 1.3%), and changes in both cortical vBMD and cortical surface BMD were significantly greater with ABL versus TPTD. In the TPTD group, changes in cortical vBMD were inversely correlated with changes in serum CTX (carboxy-terminal telopeptide of type I collagen) and PINP (procollagen type I N-terminal propeptide), suggesting that higher bone turnover may have attenuated cortical gains.

CONCLUSION

These results suggest previously reported differences in areal BMD increases between ABL and TPTD may be due to differential effects on cortical vBMD. Further studies are warranted to investigate how these differences affect therapeutic impact on hip strength in postmenopausal women with osteoporosis.

The effects of teriparatide and bisphosphonates on new fractures in postmenopausal women with osteoporosis: A protocol for systematic review and meta-analysis

BACKGROUND

To systematically evaluate the efficacy of teriparatide and bisphosphonates in preventing fractures in postmenopausal women with osteoporosis.

MATERIALS AND METHODS

We performed a systematic search of PubMed, Embase, and the Cochrane Library for randomized controlled trials (RCTs) that compared teriparatide and bisphosphonates for osteoporosis treatment. Searches were performed without language restrictions and included studies from beginning of time to March 2019. Two authors independently screened and extracted the selected article. The quality of the included studies was evaluated using the Cochrane system evaluation method. Data were extracted and analysed using RevMan 5.2 software.

RESULTS

Nine RCTs were included for a total of 2990 postmenopausal women with osteoporosis. Of these, 1515 patients were treated with teriparatide and 1475 were treated with bisphosphonates. After pooling the data of 9 studies, there were significant differences between teriparatide and bisphosphonates [relative risk (RR): 0.61, 95% confidence interval (CI) (0.51, 0.74)] in the prevention of fractures according to different follow-up durations (P < .05), whatever alendronate [RR: 0.51, 95% CI (0.27, 0.95)] and other bisphosphonates [RR: 0.63, 95% CI (0.51, 0.77)]. In addition, we found significant differences between teriparatide and bisphosphonates in the prevention of vertebral fractures [RR: 0.47, 95% CI (0.35, 0.64)] and non-vertebral fractures [RR: 0.76, 95% CI (0.58,0.99)]. There were no significant differences in adverse effects between teriparatide and bisphosphonates [RR: 0.89, 95% CI (0.76, 1.03)].

CONCLUSIONS

Based on the results of our meta-analysis, teriparatide was better than bisphosphonates in preventing fractures in postmenopausal women with osteoporosis both in the short-term and long-term follow-up periods. Teriparatide was superior to bisphosphonates in preventing vertebral and non-vertebral fractures. These drugs did not differ in terms of their adverse effects. More high-quality studies are needed to compare other factors such as costs and adverse reactions.

Effects of Odanacatib on Bone Structure and Quality in Postmenopausal Women With Osteoporosis: 5-Year Data From the Phase 3 Long-Term Odanacatib Fracture Trial (LOFT) and its Extension

Odanacatib (ODN), a selective oral inhibitor of cathepsin K, was an investigational agent previously in development for the treatment of osteoporosis. In this analysis, the effects of ODN on bone remodeling/modeling and structure were examined in the randomized, double-blind, placebo-controlled, event-driven, Phase 3, Long-term Odanacatib Fracture Trial (LOFT; NCT00529373) and planned double-blind extension in postmenopausal women with osteoporosis. A total of 386 transilial bone biopsies, obtained from consenting patients at baseline (ODN n = 17, placebo n = 23), month 24 (ODN n = 112, placebo n = 104), month 36 (ODN n = 42, placebo n = 41), and month 60 (ODN n = 27, placebo n = 20) were assessed by dynamic and static bone histomorphometry. Patient characteristics at baseline and BMD changes over 5 years for this subset were comparable to the overall LOFT population. Qualitative assessment of biopsies revealed no abnormalities. Consistent with the mechanism of ODN, osteoclast number was higher with ODN versus placebo over time. Regarding bone remodeling, dynamic bone formation indices in trabecular, intracortical, and endocortical surfaces were generally similar in ODN-treated versus placebo-treated patients after 2 years of treatment. Regarding periosteal modeling, the proportion of patients with periosteal double labels and the bone formation indices increased over time in the ODN-treated patients compared with placebo. This finding supported the observed numerical increase in cortical thickness at month 60 versus placebo. In conclusion, ODN treatment for 5 years did not reduce bone remodeling and increased the proportion of patients with periosteal bone formation. These results are consistent with the mechanism of action of ODN, and are associated with continued BMD increases and reduced risk of fractures compared with placebo in the LOFT Phase 3 fracture trial. © 2020 American Society for Bone and Mineral Research.

Zoledronic Acid Substantially Improves Bone Microarchitecture and Biomechanical Properties After Rotator Cuff Repair in a Rodent Chronic Defect Model

BACKGROUND

Bone mineral density at the humeral head is reduced in patients with chronic rotator cuff tears. Bone loss in the humeral head is associated with repair failure after rotator cuff reconstruction. Bisphosphonates (eg, zoledronic acid) increase bone mineral density.

HYPOTHESIS

Zoledronic acid improves bone mineral density of the humeral head and biomechanical properties of the enthesis after reconstruction of chronic rotator cuff tears in rats.

STUDY DESIGN

Controlled laboratory study.

METHODS

A total of 32 male Sprague-Dawley rats underwent unilateral (left) supraspinatus tenotomy with delayed transosseous rotator cuff reconstruction after 3 weeks. All rats were sacrificed 8 weeks after rotator cuff repair. Animals were randomly assigned to 1 of 2 groups. At 1 day after rotator cuff reconstruction, the intervention group was treated with a single subcutaneous dose of zoledronic acid at 100 µg/kg bodyweight, and the control group received 1 mL of subcutaneous saline solution. In 12 animals of each group, micro-computed tomography scans of both shoulders were performed as well as biomechanical testing of the supraspinatus enthesis of both sides. In 4 animals of each group, histological analyses were conducted.

RESULTS

In the intervention group, bone volume fraction (bone volume/total volume [BV/TV]) of the operated side was higher at the lateral humeral head (P = .005) and the medial humeral head (P = .010) compared with the control group. Trabecular number on the operated side was higher at the lateral humeral head (P = .004) and the medial humeral head (P = .001) in the intervention group. Maximum load to failure rates on the operated side were higher in the intervention group (P < .001). Cortical thickness positively correlated with higher maximum load to failure rates in the intervention group (r = 0.69; P = .026). Histological assessment revealed increased bone formation in the intervention group.

CONCLUSION

Single-dose therapy of zoledronic acid provided an improvement of bone microarchitecture at the humeral head as well as an increase of maximum load to failure rates after transosseous reconstruction of chronic rotator cuff lesions in rats.

CLINICAL RELEVANCE

Zoledronic acid improves bone microarchitecture as well as biomechanical properties after reconstruction of chronic rotator cuff tears in rodents. These results need to be verified in clinical investigations.

Bisphosphonate-Induced Deterioration of Osteomalacia in Undiagnosed Adult Fanconi Syndrome

We describe two women with a misdiagnosed fracturing bone disease who were treated erroneously with i.v. zoledronate. Over the next year, they suffered marked clinical and radiographic deterioration in skeletal disease. Both were eventually diagnosed with hypophosphatemic osteomalacia secondary to acquired Fanconi syndrome (caused by light-chain myeloma in one case and tenofovir treatment in the other). Appropriate treatment with phosphate supplementation was instituted with clinical improvement. These cases illustrate the importance of not missing osteomalacia in adults presenting with fractures, and the potentially damaging effects of treatment with long-acting inhibitors of bone resorption in these circumstances. © 2020 The Authors. JBMR Plus published by Wiley Periodicals, Inc. on behalf of American Society for Bone and Mineral Research.

Standard Versus Cyclic Teriparatide and Denosumab Treatment for Osteoporosis: A Randomized Trial

In the absence of an intervening antiresorptive agent, cyclic administration of teriparatide does not increase bone mineral density (BMD) more than standard daily therapy. Because denosumab is a potent antiresorptive agent with a rapid off-effect, we hypothesized that it might be the optimal agent to help maximize bone gains with cyclic teriparatide. In this 3-year protocol, 70 postmenopausal women with osteoporosis were randomized to 18 months of teriparatide followed by 18 months of denosumab (standard) or three separate 12-month cycles of 6 months of teriparatide followed by 6 months of denosumab (cyclic). BMD (dual-energy X-ray absorptiometry [DXA]) measurements of lumbar spine (LS), total hip (TH), femoral neck (FN), and 1/3 radius (RAD) were performed every 6 months and total body bone mineral (TBBM) at 18 and 36 months. Baseline descriptive characteristics did not differ between groups except for a minimal difference in LS BMD but not T-score (mean age 65 years, mean LS T-score - 2.7). In the standard group, BMD increments at 36 months were: LS 16%, TH 4%, FN 3%, and TBBM 4.8% (all p < 0.001 versus baseline). In the cyclic group, 36-month BMD increments were similar: LS 12%, TH 4%, FN 4%, and TBBM 4.1% (all p < 0.001 versus baseline). At 36 months, the LS BMD increase with standard was slightly larger than with cyclic (p = 0.04), but at 18 months, in the cyclic group, there was no decline in RAD or TBBM (p = 0.007 and < 0.001, respectively, versus standard). Although the cyclic regimen did not improve BMD compared with standard at 36 months, there appeared to be a benefit at 18 months, especially in the highly cortical skeletal sites. This could be clinically relevant in patients at high imminent risk of fracture, particularly at nonvertebral sites. © 2019 American Society for Bone and Mineral Research. © 2019 American Society for Bone and Mineral Research.

Administration of teriparatide for four years cyclically compared to two years daily in treatment Naïve and alendronate treated women

PURPOSE

We evaluated if equivalent doses of TPTD given cyclically over 4-years could increase BMD >2-years of daily TPTD in 2 cohorts of women; previously untreated (Rx-Naïve) and women previously treated with ALN (ALN-Rx).

METHODS

In Rx-Naïve, women were randomized to daily TPTD for 24 months (Daily; n = 23) or cyclic TPTD for 48 months (3 months on, 3 months off; Cyclic; n = 25). In ALN-Rx, women were randomized to continued ALN plus daily TPTD for 24 months, followed by ALN alone for 24 months (Daily; n = 21) or TPTD for 48 months (3 months on, 3 months off) while ALN was continued (Cyclic; n = 20). BMD (DXA) was measured at spine (LS), total hip (TH) and femoral neck (FN). The primary analysis compared 4 years of cyclic therapy to 2 years of daily therapy in RX-naïve and ALN-RX cohorts.

RESULTS

In Rx-Naïve, BMD changes at 24 months after Daily TPTD vs. 48 months after Cyclic TPTD were: LS 8.6% vs. 6.9%; TH 2.5% vs. 2.6%, and FN 1.6% vs. 2.2%. None of the BMD changes differed significantly between groups but all changes were significant over time within each group (p < 0.01 except for FN where p = 0.17 Daily; p = 0.09 Cyclic). In ALN-Rx, BMD changes at 24 months after Daily TPTD vs. 48 months after Cyclic TPTD were: LS 7.5% vs. 7.2%; TH 3.8% vs. 4.1%, and FN 3.2% vs. 2.5%. There were no differences between groups but all changes were significant within each group (p < 0.01).

CONCLUSION

The same cumulative dose of TPTD given cyclically for 4-years, does not increase BMD more than standard daily TPTD over 2-years in either Rx-Naïve or ALN-Rx women.

TRIAL REGISTRATION

NCT00668941.

Longitudinal Effects of Teriparatide or Zoledronic Acid on Bone Modeling- and Remodeling-Based Formation in the SHOTZ Study

Previously, we reported on bone histomorphometry, biochemical markers, and bone mineral density distribution after 6 and 24 months of treatment with teriparatide (TPTD) or zoledronic acid (ZOL) in the SHOTZ study. The study included a 12-month primary study period, with treatment (TPTD 20 μg/d by subcutaneous injection or ZOL 5 mg/yr by intravenous infusion) randomized and double-blind until the month 6 biopsy (TPTD, n = 28; ZOL, n = 30 evaluable), then open-label, with an optional 12-month extension receiving the original treatment. A second biopsy (TPTD, n = 10; ZOL, n = 9) was collected from the contralateral side at month 24. Here we present data on remodeling-based bone formation (RBF), modeling-based bone formation (MBF), and overflow modeling-based bone formation (oMBF, modeling overflow adjacent to RBF sites) in the cancellous, endocortical, and periosteal envelopes. RBF was significantly greater after TPTD versus ZOL in all envelopes at 6 and 24 months, except the periosteal envelope at 24 months. MBF was significantly greater with TPTD in all envelopes at 6 months but not at 24 months. oMBF was significantly greater at 6 months in the cancellous and endocortical envelopes with TPTD, with no significant differences at 24 months. At 6 months, total bone formation surface was also significantly greater in each envelope with TPTD treatment (all p < 0.001). For within-group comparisons from 6 to 24 months, no statistically significant changes were observed in RBF, MBF, or oMBF in any envelope for either the TPTD or ZOL treatment groups. Overall, TPTD treatment was associated with greater bone formation than ZOL. Taken together the data support the view that ZOL is a traditional antiremodeling agent, wheareas TPTD is a proremodeling anabolic agent that increases bone formation, especially that associated with bone remodeling, including related overflow modeling, with substantial modeling-based bone formation early in the course of treatment. © 2017 American Society for Bone and Mineral Research.

Optimizing Sequential and Combined Anabolic and Antiresorptive Osteoporosis Therapy

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.

Remodeling- and Modeling-Based Bone Formation With Teriparatide Versus Denosumab: A Longitudinal Analysis From Baseline to 3 Months in the AVA Study

There has been renewed interest of late in the role of modeling-based formation (MBF) during osteoporosis therapy. Here we describe early effects of an established anabolic (teriparatide) versus antiresorptive (denosumab) agent on remodeling-based formation (RBF), MBF, and overflow MBF (oMBF) in human transiliac bone biopsies. Postmenopausal women with osteoporosis received subcutaneous teriparatide (n = 33, 20 μg/d) or denosumab (n = 36, 60 mg once/6 months), open-label for 6 months at 7 US and Canadian sites. Subjects received double fluorochrome labeling at baseline and before biopsy at 3 months. Sites of bone formation were designated as MBF if the underlying cement line was smooth, RBF if scalloped, and oMBF if formed over smooth cement lines adjacent to scalloped reversal lines. At baseline, mean RBF/bone surface (BS), MBF/BS, and oMBF/BS were similar between the teriparatide and denosumab groups in each bone envelope assessed (cancellous, endocortical, periosteal). All types of formation significantly increased from baseline in the cancellous and endocortical envelopes (differences p < 0.001) with teriparatide (range of changes 2.9- to 21.9-fold), as did MBF in the periosteum (p < 0.001). In contrast, all types of formation were decreased or not significantly changed with denosumab, except MBF/BS in the cancellous envelope, which increased 2.5-fold (difference p = 0.048). These data highlight mechanistic differences between these agents: all 3 types of bone formation increased significantly with teriparatide, whereas formation was predominantly decreased or not significantly changed with denosumab, except for a slight increase in MBF/BS in the cancellous envelope. © 2017 American Society for Bone and Mineral Research.

Effects of teriparatide and risedronate on new fractures in post-menopausal women with severe osteoporosis (VERO): a multicentre, double-blind, double-dummy, randomised controlled trial

BACKGROUND

No clinical trials have compared osteoporosis drugs with incident fractures as the primary outcome. We compared the anti-fracture efficacy of teriparatide with risedronate in patients with severe osteoporosis.

METHODS

In this double-blind, double-dummy trial, we enrolled post-menopausal women with at least two moderate or one severe vertebral fracture and a bone mineral density T score of less than or equal to -1·50. Participants were randomly assigned to receive 20 μg of teriparatide once daily plus oral weekly placebo or 35 mg of oral risedronate once weekly plus daily injections of placebo for 24 months. The primary outcome was new radiographic vertebral fractures. Secondary, gated outcomes included new and worsened radiographic vertebral fractures, clinical fractures (a composite of non-vertebral and symptomatic vertebral), and non-vertebral fractures. This study is registered with ClinicalTrials.gov (NCT01709110) and EudraCT (2012-000123-41).

FINDINGS

We enrolled 680 patients in each group. At 24 months, new vertebral fractures occurred in 28 (5·4%) of 680 patients in the teriparatide group and 64 (12·0%) of 680 patients in the risedronate group (risk ratio 0·44, 95% CI 0·29-0·68; p<0·0001). Clinical fractures occurred in 30 (4·8%) of 680 patients in the teriparatide group compared with 61 (9·8%) of 680 in the risedronate group (hazard ratio 0·48, 95% CI 0·32-0·74; p=0·0009). Non-vertebral fragility fractures occurred in 25 (4·0%) patients in the teriparatide group and 38 (6·1%) in the risedronate group (hazard ratio 0·66; 95% CI 0·39-1·10; p=0·10).

INTERPRETATION

Among post-menopausal women with severe osteoporosis, the risk of new vertebral and clinical fractures is significantly lower in patients receiving teriparatide than in those receiving risedronate.

FUNDING

Lilly.

Alendronate promotes osteoblast differentiation and bone formation in ovariectomy-induced osteoporosis through interferon-β/signal transducer and activator of transcription 1 pathway

Alendronate is commonly used for the treatment of postmenopausal osteoporosis; however, the underlying pathological molecular mechanisms of its action remain unclear. In the present study, the alendronate-treated signaling pathway in bone metabolism in rats with ovariectomy induced by osteoporosis was investigated. Rats with osteoporosis were orally administered alendronate or phosphate-buffered saline (control). In addition, the interferon-β (IFN-β)/signal transducer and activator of transcription 1 (STAT1) signaling pathway was investigated in osteoblasts following treatment with alendronate in vitro and in vivo. During the differentiation period, IFN-β (100 ng/ml) was used to treat the osteoblast cells, and the activity, viability and bone metabolism-associated gene expression levels (STAT1, p-STAT1, Fra1, TRAF6 and SOCS1) were analyzed in osteoblast cells. Histopathological changes were used to evaluate osteoblasts, osteoclasts, inflammatory phase of bone healing and osteonecrotic areas. The results demonstrated that alendronate significantly inhibited the activity of osteoporotic osteoclasts by stimulating expression of IFN-β, as well as markedly improved the viability and activity of osteoblasts compared with the control group. In addition, alendronate increased the expression and phosphorylation levels of STAT1 in osteoclasts, enhanced osteoblast differentiation, upregulated the expression levels of alkaline phosphatase and osteocalcin, and increased the expression of osteoblast differentiation-associated genes (osteocalcin, osterix and Runx2). Inhibition of IFN-β expression canceled the benefits of alendronate-mediated osteoblast differentiation. Notably, alendronate enhanced bone formation in rats with osteoporosis induced by ovariectomy. In conclusion, these findings suggest that alendronate can regulate osteoblast differentiation and bone formation in rats with osteoporosis induced by ovariectomy through upregulation of IFN-β/STAT1 signaling pathway.

New anabolic therapies for osteoporosis

Osteoporosis is characterized by low bone mass and qualitative structural abnormalities of bone tissue, leading to increased bone fragility that results in fractures. Pharmacological therapy is aimed at decreasing the risk of fracture, mainly correcting the imbalance between bone resorption and formation at the level of bone remodeling units. Anabolic therapy has the capability to increase bone mass to a greater extent than traditional antiresorptive agents. The only currently available drug licensed is parathyroid hormone 1-34 (teriparatide); new drugs are on the horizon, targeting the stimulation of bone formation, and therefore improving bone mass, structure and ultimately skeletal strength. These are represented by abaloparatide (a 34-amino acid peptide which incorporates critical N-terminal residues, shared by parathyroid hormone and parathyroid hormone-related protein, followed by sequences unique to the latter protein) and romosozumab (an antibody to sclerostin). In the future, the availability of new anabolic treatment will allow a more extensive utilization of additive and sequential approach, with the goal of both prolonging the period of treatment and, more importantly, avoiding the side effects consequent to long-term use of traditional drugs.

Vibrational spectroscopic techniques to assess bone quality

Although musculoskeletal diseases such as osteoporosis are diagnosed and treatment outcome is evaluated based mainly on routine clinical outcomes of bone mineral density (BMD) by DXA and biochemical markers, it is recognized that these two indicators, as valuable as they have proven to be in the everyday clinical practice, do not fully account for manifested bone strength. Thus, the term bone quality was introduced, to complement considerations based on bone turnover rates and BMD. Bone quality is an "umbrella" term that incorporates the structural and material/compositional characteristics of bone tissue. Vibrational spectroscopic techniques such as Fourier transform infrared microspectroscopy (FTIRM) and imaging (FTIRI), and Raman spectroscopy, are suitable analytical tools for the determination of bone quality as they provide simultaneous, quantitative, and qualitative information on all main bone tissue components (mineral, organic matrix, tissue water), in a spatially resolved manner. Moreover, the results of such analyses may be readily combined with the outcomes of other techniques such as histology/histomorphometry, small angle X-ray scattering, quantitative backscattered electron imaging, and nanoindentation.

Osteoporosis treatment: a missed opportunity

Osteoporosis affects 1.2 million Australians and, in 2012, fractures due to osteoporosis and osteopenia in Australians aged over 50 years cost $2.75 billion. Even minor minimal trauma fractures are associated with increased morbidity and mortality. Despite increasing therapeutic options for managing osteoporosis, fewer than 20% of patients with a minimal trauma fracture are treated or investigated for osteoporosis, so under-treatment is extremely common. Fracture risk assessment is important for selecting patients who require specific anti-osteoporosis therapy. Post-menopausal osteoporosis is frequently due to an imbalance in bone remodelling, with bone resorption exceeding bone formation. Antiresorptive drugs reduce the number, activity and lifespan of osteoclasts, and include bisphosphonates, oestrogen, selective oestrogen receptor-modulating drugs, strontium ranelate, and the human monoclonal antibody denosumab. Teriparatide is the only anabolic agent currently available that stimulates osteoblast recruitment and activity; its antifracture efficacy for non-vertebral fractures increases with the duration of therapy for up to 2 years when it is associated with persisting increases in bone formation rate at the tissue level. Newer anabolic agents are imminent and include an analogue of parathyroid hormone-related protein, abaloparatide, and a humanised monoclonal antibody to an inhibitor of bone formation, romosozumab. Selection of anti-osteoporosis therapy should be individualised to patients, and the duration of bisphosphonate therapy has been covered in recent guidelines. The benefits of treatment far outweigh any risks associated with long term treatment. General practitioners need to take up the challenge imposed by osteoporosis and become champions of change to close the evidence-treatment gap.

Effects of abaloparatide-SC (BA058) on bone histology and histomorphometry: The ACTIVE phase 3 trial

There are a number of effective treatments for osteoporosis but most are in the antiresorptive class of compounds. Abaloparatide-SC is a new osteoanabolic agent, which increased bone mineral density and lowered the risk of osteoporosis-related fractures in the phase 3 ACTIVE trial. The objective of this report is to describe the effects of abaloparatide-SC 80μg on bone histology and histomorphometry in iliac crest bone biopsies from this trial in which participants were randomized to receive blinded daily subcutaneous injections of placebo or abaloparatide-SC 80μg/d or open-label teriparatide 20μg/d for 18months. Iliac crest bone biopsies were obtained between 12 and 18months. Qualitative histological analysis of biopsies from abaloparatide-SC-treated patients revealed normal bone microarchitecture without evidence of adverse effects on mineralization or on the formation of normal lamellar bone. There were no bone marrow abnormalities, marrow fibrosis nor was there presence of excess osteoid or woven bone. There were few significant differences among the three treatment groups in a standard panel of static and dynamic histomorphometric indices. The mineral apposition rate was higher in the teriparatide-treated group than in the placebo-treated group. The eroded surface was lower in the abaloparatide-SC-treated group than in the placebo-treated group. Cortical porosity was higher in both the abaloparatide-SC- and the teriparatide-treated groups than in the placebo-treated group. We conclude that histological and histomorphometric analysis of iliac crest bone biopsies from subjects who were treated for up to 18months with abaloparatide-SC showed no evidence of concern for bone safety.

TRIAL REGISTRATION

ClinicalTrials.gov number NCT01343004.

Ovarian hormone depletion affects cortical bone quality differently on different skeletal envelopes

The physical properties of bone tissue are determined by the organic and mineral matrix, and are one aspect of bone quality. As such, the properties of mineral and matrix are a major contributor to bone strength, independent of bone mass. Cortical bone quality may differ regionally on the three skeletal envelopes that compose it. Each of these envelopes may be affected differently by ovarian hormone depletion. Identifying how these regions vary in their tissue adaptive response to ovarian hormones can inform our understanding of how tissue quality contributes to overall bone strength in postmenopausal women. We analyzed humeri from monkeys that were either SHAM-operated or ovariectomized. Raman microspectroscopic analysis was performed as a function of tissue age based on the presence of multiple fluorescent double labels, to determine whether bone compositional properties (mineral/matrix ratio, tissue water, glycosaminoglycan, lipid, and pyridinoline contents, and mineral maturity/crystallinity) are similar between periosteal, osteonal, and endosteal surfaces, as well as to determine the effects of ovarian hormone depletion on them. The results indicate that mineral and organic matrix characteristics, and kinetics of mineral and organic matrix modifications as a function of tissue age are different at periosteal vs. osteonal and endosteal surfaces. Ovarian hormone depletion affects the three cortical surfaces (periosteal, osteonal, endosteal) differently. While ovarian hormone depletion does not significantly affect the quality of either the osteoid or the most recently mineralized tissue, it significantly affects the rate of subsequent mineral accumulation, as well as the kinetics of organic matrix modifications, culminating in significant differences within interstitial bone. These results highlight the complexity of the cortical bone compartments, add to existing knowledge on the effects of ovarian hormone depletion on local cortical bone properties, and may contribute to a better understanding of the location specific action of drugs used in the management of postmenopausal osteoporosis.

Treatment Sequence Matters: Anabolic and Antiresorptive Therapy for Osteoporosis

The effects of anabolic medications (teriparatide [TPTD] and parathyroid hormone [PTH]) differ in patients who have received recent treatment with potent antiresorptives. This perspective reviews studies evaluating bone density (BMD) and histomorphometric effects of treatment sequences beginning with TPTD/PTH followed by potent antiresorptives and those beginning with potent antiresorptives followed by switching to or adding TPTD. Effect of treatment sequence on spine BMD outcome is minor, with modest quantitative differences. However, when individuals established on potent bisphosphonates are switched to TPTD, hip BMD declines below baseline for at least the first 12 months after the switch to TPTD. This transient hip BMD loss is more prominent when the antiresorptive is denosumab; in this setting, hip BMD remains below baseline for almost a full 24 months. In a controlled comparison of those who switched from alendronate to TPTD versus those who added TPTD to ongoing alendronate, the effect on hip BMD was improved with combination therapy. Furthermore, hip strength improved with the addition of TPTD to ongoing alendronate, whereas it was neutral after switching from alendronate to TPTD, primarily due to the effect on cortical bone. Bone biopsy studies indicate that TPTD stimulates bone formation in patients who have not been treated previously as well as in patients on prior and ongoing bisphosphonates. Histomorphometric evidence suggests that use of alendronate with TPTD blocks the TPTD-induced increase in cortical porosity. When possible, we suggest anabolic therapy first, followed by potent antiresorptive therapy. The common practice of switching to TPTD only after patients have an inadequate response to antiresorptives (intercurrent fracture or inadequate BMD effect) is not the optimal utilization of anabolic treatment. In fact, this may result in transient loss of hip BMD and strength. In this setting, continuing a potent antiresorptive while starting TPTD might improve hip outcomes. © 2017 American Society for Bone and Mineral Research.

Differential Effects of Teriparatide and Zoledronic Acid on Bone Mineralization Density Distribution at 6 and 24 Months in the SHOTZ Study

The Skeletal Histomorphometry in Patients on Teriparatide or Zoledronic Acid Therapy (SHOTZ) study assessed the progressive effects of teriparatide (TPTD) and zoledronic acid (ZOL) on bone remodeling and material properties in postmenopausal women with osteoporosis. Previously, we reported that biochemical and histomorphometric bone formation indices were significantly higher in patients receiving TPTD versus ZOL. Here we report bone mineralization density distribution (BMDD) results based on quantitative backscattered electron imaging (qBEI). The 12-month primary study was randomized and double blind until the month 6 biopsy, then open label. Patients (TPTD, n = 28; ZOL, n = 31) were then eligible to enter a 12-month open-label extension with their original treatment: TPTD 20 μg/d (subcutaneous injection) or ZOL 5 mg/yr (intravenous infusion). A second biopsy was collected from the contralateral side at month 24 (TPTD, n = 10; ZOL, n = 10). In cancellous bone, ZOL treatment was associated at 6 and 24 months with significantly higher average degree of mineralization (CaMEAN, +2.2%, p = 0.018; +3.9%, p = 0.009, respectively) and with lower percentage of low mineralized areas (CaLOW , -34.6%, p = 0.029; -33.7%, p = 0.025, respectively) and heterogeneity of mineralization CaWIDTH (-12.3%, p = 0.003; -9.9%, p = 0.012, respectively), indicating higher mineralization density and more homogeneous mineral content versus TPTD. Within the ZOL group, significant changes were found in all parameters from month 6 to 24, indicating a progressive increase in mineralization density. In sharp contrast, mineralization density did not increase over time with TPTD, reflecting ongoing deposition of new bone. Similar results were observed in cortical bone. In this study, TPTD stimulated new bone formation, producing a mineralized bone matrix that remained relatively heterogeneous with a stable mean mineral content. ZOL slowed bone turnover and prolonged secondary mineralization, producing a progressively more homogeneous and highly mineralized bone matrix. Although both TPTD and ZOL increase clinical measures of bone mineral density (BMD), this study shows that the underlying mechanisms of the BMD increases are fundamentally different. © 2016 American Society for Bone and Mineral Research.

Differential Effects of Teriparatide and Denosumab on Intact PTH and Bone Formation Indices: AVA Osteoporosis Study

We compared effects of teriparatide and denosumab on PTH, bone turnover markers, and bone histomorphometry in osteoporotic postmenopausal women. The findings were inconsistent with an early indirect anabolic effect of denosumab.