Parathyroid hormone added to established hormone therapy: effects on vertebral fracture and maintenance of bone mass after parathyroid hormone withdrawal

Treatment Sequence for Osteoporosis

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.

[The recombinant human parathyroid hormone, teriparatide as an alternative remedy for the medication-related osteonecrosis of the jaw]

In developed countries, osteoporosis is one of the most common debilitating conditions in the population over the age of 50. Unfortunately, the pathomechanism of the disease is still not fully understood. Nowadays, the administration of antiresorptive drugs blocking osteoclastic activity is the most commonly used medication to slow down the speed of the bone loss. One of the uncommon side effects of such drugs is the medication-related osteonecrosis of the jaw (MRONJ). Recently, a number of alternative therapeutic approaches has been tested and published, amongst them the recombinant human parathyroid hormone (rhPTH, teriparatide) use, which is turning into a promising treatment modality. According to certain meta-analyses, its pharmacological effect on increasing bone mineral density and controlling pathological vertebral fractures is superior to antiresorptive drugs; however, the so-called "off-label" application of teriparatide remains controversial. As intermittent administration of teriparatide stimulates bone formation, several animal and clinical studies indicated that systemic application of teriparatide shortened fracture healing time and improved quality of the callus and the newly formed bone. Furthermore, recently several clinical studies showed the beneficial effect of the intermittent rhPTH administration in the management of MRONJ. This article reviews the history of the anabolic effect of the low-dose rhPTH discovery, provides evidence-based data from animal and human studies, summarizes its biological mechanisms and the clinical benefits of the anabolic therapy and also their possible role in the management of MRONJ. The majority of the clinical data indicates that, in the case of therapy-resistant osteonecrosis, it may be worthwhile to apply short-term intermittent teriparatide therapy. Notwithstanding, more randomized clinical trials are necessary in order to confirm the efficacy and the safety of the use of teriparatide in the treatment of MRONJ. Orv Hetil. 2023; 164(36): 1406-1415.

Fracture risk reduction and safety by osteoporosis treatment compared with placebo or active comparator in postmenopausal women: systematic review, network meta-analysis, and meta-regression analysis of randomised clinical trials

OBJECTIVE

To review the comparative effectiveness of osteoporosis treatments, including the bone anabolic agents, abaloparatide and romosozumab, on reducing the risk of fractures in postmenopausal women, and to characterise the effect of antiosteoporosis drug treatments on the risk of fractures according to baseline risk factors.

DESIGN

Systematic review, network meta-analysis, and meta-regression analysis of randomised clinical trials.

DATA SOURCES

Medline, Embase, and Cochrane Library to identify randomised controlled trials published between 1 January 1996 and 24 November 2021 that examined the effect of bisphosphonates, denosumab, selective oestrogen receptor modulators, parathyroid hormone receptor agonists, and romosozumab compared with placebo or active comparator.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Randomised controlled trials that included non-Asian postmenopausal women with no restriction on age, when interventions looked at bone quality in a broad perspective. The primary outcome was clinical fractures. Secondary outcomes were vertebral, non-vertebral, hip, and major osteoporotic fractures, all cause mortality, adverse events, and serious cardiovascular adverse events.

RESULTS

The results were based on 69 trials (>80 000 patients). For clinical fractures, synthesis of the results showed a protective effect of bisphosphonates, parathyroid hormone receptor agonists, and romosozumab compared with placebo. Compared with parathyroid hormone receptor agonists, bisphosphonates were less effective in reducing clinical fractures (odds ratio 1.49, 95% confidence interval 1.12 to 2.00). Compared with parathyroid hormone receptor agonists and romosozumab, denosumab was less effective in reducing clinical fractures (odds ratio 1.85, 1.18 to 2.92 for denosumab v parathyroid hormone receptor agonists and 1.56, 1.02 to 2.39 for denosumab v romosozumab). An effect of all treatments on vertebral fractures compared with placebo was found. In the active treatment comparisons, denosumab, parathyroid hormone receptor agonists, and romosozumab were more effective than oral bisphosphonates in preventing vertebral fractures. The effect of all treatments was unaffected by baseline risk indicators, except for antiresorptive treatments that showed a greater reduction of clinical fractures compared with placebo with increasing mean age (number of studies=17; β=0.98, 95% confidence interval 0.96 to 0.99). No harm outcomes were seen. The certainty in the effect estimates was moderate to low for all individual outcomes, mainly because of limitations in reporting, nominally indicating a serious risk of bias and imprecision.

CONCLUSIONS

The evidence indicated a benefit of a range of treatments for osteoporosis in postmenopausal women for clinical and vertebral fractures. Bone anabolic treatments were more effective than bisphosphonates in the prevention of clinical and vertebral fractures, irrespective of baseline risk indicators. Hence this analysis provided no clinical evidence for restricting the use of anabolic treatment to patients with a very high risk of fractures.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42019128391.

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.

Advancement in the Treatment of Osteoporosis and the Effects on Bone Healing

Osteoporosis (OP) is a major global health concern, with aging being one of the most important risk factors. Osteoarthritis (OA) is also an age-related disorder. Patients with OP and/or OA may be treated surgically for fractures or when their quality of life is impaired. Poor bone quality due to OP can seriously complicate the stability of a bone fixation construct and/or surgical fracture treatment. This review summarizes the current knowledge on the pathophysiology of normal and osteoporotic bone healing, the effect of a bone fracture on bone turnover markers, the diagnosis of a low bone mineral density (BMD) before surgical intervention, and the effect of available anti-osteoporosis treatment. Interventions that improve bone health may enhance the probability of favorable surgical outcomes. Fracture healing and the treatment of atypical femoral fractures are also discussed.

Effect of adjuvant therapy with teriparatide in patients with thoracolumbar osteoporotic vertebral fractures who underwent vertebroplasty with posterior spinal fusion

Teriparatide (TPTD) administration has a potent osteogenic action and promotes the healing of osteoporotic vertebral fractures (OVFs). We aimed to investigate the outcomes of vertebroplasty with posterior spinal fusion (VP + PSF) and determine the impact of perioperative TPTD administration. We included 73 patients (18 male and 55 female patients; mean age: 78 years) with thoracolumbar OVFs who underwent VP + PSF and were followed-up for at least 2 years. Twenty-three patients who received TPTD perioperatively for > 3 months were included in the TPTD group, and the remaining 50 patients were included in the non-TPTD group. Radiographic findings regarding sagittal alignment and clinical outcomes in both groups were compared. The mean duration of TPTD administration was 17.5 ± 5.0 months (range 4–24 months). The mean loss of correction of local kyphosis angle in the TPTD group (4.0°) was lesser than that in the non-TPTD group (7.5°; p < 0.05); however, no significant differences were observed between the groups regarding global sagittal alignment, the occurrence of subsequent vertebral fractures, pedicle screw loosening and treatment-efficacy rates of clinical outcomes. Local kyphosis correction in patients who underwent VP + PSF for OVFs could be maintained through perioperative TPTD administration; however, TPTD administration had little effect on clinical outcomes.

Neoadjuvant teriparatide therapy targeting the osteoporotic spine: influence of administration period from the perspective of bone histomorphometry

OBJECTIVE

Teriparatide (TPTD) is a potent promoter of early-stage osteogenesis and may be a useful adjuvant therapy to reduce complications related to bone fragility in spinal surgery patients with osteoporosis. However, effective neoadjuvant TPTD therapy regimens remain poorly understood. This study aimed to examine the effect of preoperative TPTD administration on cancellous bone with bone histomorphometry and to clarify the timing of preoperative TPTD administration for patients with spinal fusion and osteoporosis.

METHODS

In this longitudinal multicenter study, 57 patients with spinal fusion and osteoporosis, who consented to undergo iliac biopsy, were allocated to the following treatment groups: neoadjuvant TPTD therapy group (n = 42) and no neoadjuvant therapy (NTC) group (n = 15). Patients in the TPTD group were categorized into subgroups on the basis of duration of preoperative TPTD administration, as follows: 1 month (n = 9), 2 months (n = 8), 3 months (n = 9), 4 months (n = 7), and 6 months (n = 9). All patient samples were preoperatively double labeled with tetracycline, and iliac biopsies were performed during spinal fusion surgery. Histomorphometric analyses were performed on nondecalcified, thin-sliced specimens. Specimens were classified on the basis of TPTD administration duration and subsequently compared with those of the NTC group. Postoperative complications and Oswestry Disability Index scores were evaluated at 1 and 2 years after surgery.

RESULTS

There were no demographic differences between groups. Mineralizing surface/bone surface, a key parameter of dynamic bone formation, started to increase after 1 month of TPTD administration; this increase became significant after 3 months of administration and peaked at 4 months, with a 6-fold increase relative to that of the NTC group. The patients who received preoperative TPTD for 3 months or more had superior clinical results in terms of the osteoporotic complication rate and Oswestry Disability Index scores, except for bisphosphonate-pretreated patients.

CONCLUSIONS

When considering neoadjuvant TPTD therapy, the authors recommend at least 3 months of preoperative administration to provide a more substantial anabolic effect from the early postoperative stage.

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.

Present and future scope of recombinant parathyroid hormone therapy in orthopaedics

Parathyroid Hormone (PTH) has a significant role in calcium metabolism. Its intermittent administration has an anabolic effect on bone mineralization. Teriparatide (PTH 1-34), a recombinant form of parathyroid hormone, is useful in the treatment of osteoporosis, fracture healing, non-union, stress fracture, augmentation of implant fixation with bone, and chondroprotection in osteoarthritis. The present review article will elaborate on the potential approved uses of recombinant PTH in orthopedics and its evolving role in the management of fracture osteosynthesis and other common challenging bone pathologies.

Emerging insights into the comparative effectiveness of anabolic therapies for osteoporosis

Over the past three decades, the mainstay of treatment for osteoporosis has been antiresorptive agents (such as bisphosphonates), which have been effective with continued administration in lowering fracture risk. However, the clinical landscape has changed as adherence to these medications has declined due to perceived adverse effects. As a result, decreases in hip fracture rates that followed the introduction of bisphosphonates have now levelled off, which is coincident with a decline in the use of the antiresorptive agents. In the past two decades, two types of anabolic agents (including three new drugs), which represent a novel approach to improving bone quality by increasing bone formation, have been approved. These therapies are expected to lead to a new clinical paradigm in which anabolic agents will be used either alone or in combination with antiresorptive agents to build new bone and reduce fracture risk. This Review examines the mechanisms of action for these anabolic agents by detailing their receptor-activating properties for key cell types in the bone and marrow niches. Using these advances in bone biology as context, the comparative effectiveness of these anabolic agents is discussed in relation to other therapeutic options for osteoporosis to better guide their clinical application in the future.

Effect of Teriparatide on Bone Remodeling and Density in Premenopausal Idiopathic Osteoporosis: A Phase II Trial

CONTEXT

Premenopausal women with idiopathic osteoporosis (IOP) have abnormal skeletal microarchitecture and variable tissue-level bone formation rate (BFR).

OBJECTIVES

Compare 6 months (M) of teriparatide versus placebo on areal bone mineral density (aBMD) by dual-energy x-ray absorptiometry (DXA), bone turnover markers (BTMs) and BFR at 3M by quadruple-labeled transiliac biopsy. Characterize 12M and 24M effects of teriparatide on aBMD and whether BTMs and BFR predict response.

DESIGN

6M phase 2 randomized controlled trial (RCT) followed by open extension.

SETTING

Tertiary referral centers.

PATIENTS

Premenopausal women with IOP.

INTERVENTIONS

A total of 41 women were randomized to either teriparatide 20 mcg (n = 28) or placebo (n = 13). After 6M, those on placebo switched to teriparatide for 24M; those on teriparatide continued for 18M.

MAIN OUTCOME MEASURES

6M RCT: Between-group differences in lumbar spine (LS) aBMD (percent change from baseline), 3M BFR, and hypercalcemia. Open-label extension: Within-group change in LS aBMD over 12M and 24M. Secondary outcomes included aBMD change at other sites and relationship between BTMs, BFR, and changes in aBMD.

FINDINGS

Over 6M, LS aBMD increased by 5.5% (95% CI: 3.83, 7.19) in teriparatide and 1.5% (95% CI: -0.73, 3.83) in placebo (P = 0.007). There were increases in 3M BTMs, and BFR (cancellous and endocortical BFR: between-groups P = 0.004). Over 24M, teriparatide increased LS aBMD by 13.2% (95% CI: 10.3, 16.2), total hip by 5.2% (95% CI: 3.7, 6.7) and femoral neck by 5.0% (95% CI: 3.2, 6.7; all P ≤ 0.001). Serum N-terminal propeptides of procollagen type 1 (P1NP) and 3M endocortical BFR were moderately associated with LS aBMD response. Teriparatide was well-tolerated.

CONCLUSIONS

Teriparatide increased BFR and formation markers and was associated with marked aBMD improvements in most premenopausal women (82%) with IOP.

Antiresorptive and anabolic agents in the prevention and reversal of bone fragility

Bone volume, microstructure and its material composition are maintained by bone remodelling, a cellular activity carried out by bone multicellular units (BMUs). BMUs are focally transient teams of osteoclasts and osteoblasts that respectively resorb a volume of old bone and then deposit an equal volume of new bone at the same location. Around the time of menopause, bone remodelling becomes unbalanced and rapid, and an increased number of BMUs deposit less bone than they resorb, resulting in bone loss, a reduction in bone volume and microstructural deterioration. Cortices become porous and thin, and trabeculae become thin, perforated and disconnected, causing bone fragility. Antiresorptive agents reduce fracture risk by reducing the rate of bone remodelling so that fewer BMUs are available to remodel bone. Bone fragility is not abolished by these drugs because existing microstructural deterioration is not reversed, unsuppressed remodelling continues producing microstructural deterioration and unremodelled bone that becomes more mineralized can become brittle. Anabolic agents reduce fracture risk by stimulating new bone formation, which partly restores bone volume and microstructure. To guide fracture prevention, this Review provides an overview of the structural basis of bone fragility, the mechanisms of remodelling and how anabolic and antiresorptive agents target remodelling defects.

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.

Combination and sequential treatment in women with postmenopausal osteoporosis

Introduction: Since postmenopausal osteoporosis is a chronic, potentially disabling condition requiring long-term treatment, the physician is expected to decide the optimal treatment strategy, e.g. how to use the available osteoanabolic and antiresorptive agents, sequentially or in combination, in the most effective and safe way, based on personalized patient care.Areas covered: Herein, the authors outline clinical data regarding the efficacy and safety of various sequential treatment strategies. More specifically, they compare the efficacy of osteoanabolic agents when they precede or follow antiresorptive treatment, as well as the efficacy of antiresorptives following other antiresorptives. Finally, the authors quote and discuss available evidence regarding the efficacy and safety of the co-administration of osteoanabolics and antiresorptives in comparison with monotherapies.Expert opinion: Initiation with an osteoanabolic agent followed by an antiresorptive seems to be the optimal treatment sequence, at least in patients with severe osteoporosis. Osteoanabolic treatment following antiresorptives seems to lead in more modest responses in bone mineral density (BMD) and bone turnover markers. Combination therapy with teriparatide and denosumab or zoledronate has achieved higher BMD gains compared to each agent alone; however, due to the high cost, combination therapy is rarely compensated. On the contrary, the combination of teriparatide with alendronate results in smaller BMD increases than TPTD monotherapy.

Reduced Bone Modeling and Unbalanced Bone Remodeling: Targets for Antiresorptive and Anabolic Therapy

Bone loss during advancing age is the net result of reduced modeling-based bone formation upon the outer (periosteal) envelope and unbalanced remodeling by basic multicellular units (BMUs) upon the three (intracortical, endocortical, and trabecular) components of the inner (endosteal) bone envelope. Each BMU deposits less bone than resorbed, reducing total bone volume and deteriorating the microstructure of the diminished residual bone volume.Antiresorptive agents like bisphosphonates reduce, but do not abolish, the rate of bone remodeling - fewer BMUs remodel, "turn over," the volume of bone. Residual unbalanced remodeling continues to slowly reduce total bone volume and deteriorate bone microstructure. By contrast, denosumab virtually abolishes remodeling so the decrease in bone volume and the deterioration in microstructure cease. The less remodeled matrix remains, leaving more time to complete the slow process of secondary mineralization which reduces the heterogeneity of matrix mineralization and allows it to become glycosylated, changes that may make the smaller and microstructurally deteriorated bone volume more brittle. Neither class of antiresorptive restores bone volume or its microstructure, despite increases in bone mineral density misleadingly suggesting otherwise. Nevertheless, these agents reduce vertebral and hip fractures by 50-60% but only reduce nonvertebral fractures by 20-30%.Restoring bone volume, microstructure, and material composition, "curing" bone fragility, may be partly achieved using anabolic therapy. Teriparatide, and probably abaloparatide, produce mainly remodeling-based bone formation by acting on BMUs existing in their resorption, reversal, or formation phase at the time of treatment and by promoting bone formation in newly initiated BMUs. Romosozumab produces modeling-based bone formation almost exclusively and decreases the surface extent of bone resorption. All three anabolic agents reduce vertebral fracture risk relative to untreated controls; parathyroid hormone 1-34 and romosozumab reduce vertebral fracture risk more greatly than risedronate or alendronate, respectively. Evidence for nonvertebral or hip fracture risk reduction relative to untreated or antiresorptive-treated controls is lacking or inconsistent. Only one study suggests sequential romosozumab followed by alendronate reduces vertebral, nonvertebral, and hip fracture risk compared to continuous alendronate alone. Whether combined antiresorptive and anabolic therapy result in superior fracture risk reduction than monotherapy is untested.

New Frontiers in Osteoporosis Therapy

Current osteoporosis medications reduce fractures significantly but have rare and serious adverse effects (osteonecrosis of the jaw, atypical femoral fractures) that may limit their safety for long-term use. Insights from basic bone biology and genetic disorders have led to recent advances in therapeutics for osteoporosis. New approaches now in clinical use include the antisclerostin monoclonal antibody romosozumab, as well as the parathyroid hormone-related peptide analog abaloparatide. Clinical trial data show significant antifracture benefits with recently approved romosozumab. Studies using abaloparatide build on our longstanding experience with teriparatide and the importance of consolidating the bone mineral density gains achieved from an anabolic agent by following it with an antiresorptive. Combination and sequential treatments using osteoporosis medications with different mechanisms of action have also been tested with promising results. On the horizon is the potential for cell-based therapies (e.g., mesenchymal stem cells) and drugs that target the elimination of senescent cells in the bone microenvironment.

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.

Combination therapy with parathyroid hormone analogs and antiresorptive agents for osteoporosis: a systematic review and meta-analysis of randomized controlled trials

Combination therapy with parathyroid hormone (PTH) analogs and antiresorptive agents may be more effective than monotherapy for the treatment of osteoporosis. This study aimed to estimate the effectiveness and safety of this combination therapy for osteoporosis. MEDLINE, EMBASE, and Cochrane Library were searched from inception to May 1, 2018, including randomized controlled trials (RCTs) with a duration of at least 6 months on adults with osteoporosis treated with combination therapy versus monotherapy. Outcomes included fractures, bone mineral density (BMD) changes, and adverse events. A meta-analysis was performed using a random-effect model, to estimate risk ratios (RRs) for fractures, and mean differences (MDs) for BMD changes. A total of 19 RCTs and 2177 patients were included. Compared with monotherapy, combination therapy had an advantage of 36% (RR, 0.64; 95% confidence interval (CI), 0.42-0.98) regarding fracture risk reduction. It also appears to improve lumbar spine BMD by 4.06% (95%CI = 2.60-5.53) and total hip BMD by 1.89% (95%CI = 1.25-2.53). No RCT reported an increased risk of serious adverse events. Among patients with osteoporosis, combination therapy was superior to monotherapy regarding improvement of the lumbar spine and total hip BMD, without risk of serious adverse events. Combination therapy also had an advantage over monotherapy on fracture risk reduction. However, owing to the limited sample size, additional larger studies are required to confirm this benefit.

Effect of Teriparatide Treatment on Circulating Periostin and Its Relationship to Regulators of Bone Formation and BMD in Postmenopausal Women With Osteoporosis

CONTEXT

Treatment of postmenopausal osteoporosis with teriparatide parathyroid hormone amino terminal 1-34 increases bone formation and improves bone microarchitecture. A possible modulator of action is periostin. In vitro experiments have shown that periostin might regulate osteoblast differentiation and bone formation through Wnt signaling. The effect of teriparatide on periostin is not currently known.

OBJECTIVES

To determine the effect of teriparatide treatment on circulating levels of periostin and other regulators of bone formation and investigate how changes in periostin relate to changes in bone turnover markers, regulators of bone formation, and bone mineral density (BMD).

PARTICIPANTS AND DESIGN

Twenty women with osteoporosis; a 2-year open-label single-arm study.

INTERVENTION

Teriparatide 20 µg was administered by subcutaneous injection daily for 104 weeks. Periostin, sclerostin, and Dickkopf-related protein 1, procollagen type I N-terminal propeptide (PINP), and C-telopeptide of type I collagen were measured in fasting serum collected at baseline (two visits) and then at weeks 1, 2, 4, 12, 26, 52, 78, and 104. BMD was measured at the lumbar spine, total hip, and femoral neck using dual energy x-ray absorptiometry.

RESULTS

Periostin levels increased by 6.6% [95% confidence interval (CI), -0.4 to 13.5] after 26 weeks of teriparatide treatment and significantly by 12.5% (95% CI, 3.3 to 21.0; P < 0.01) after 52 weeks. The change in periostin correlated positively with the change in the lumbar spine BMD at week 52 (r = 0.567; 95% CI, 0.137 to 0.817; P < 0.05) and femoral neck BMD at week 104 (r = 0.682; 95% CI, 0.261 to 0.885; P < 0.01).

CONCLUSIONS

Teriparatide therapy increases periostin secretion; it is unclear whether this increase mediates the effect of the drug on bone.

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.

Combination therapy of anabolic and nonbisphosphonates antiresorptive agents for the treatment of osteoporosis: A meta-analysis

BACKGROUND

According to the mechanisms of action, combination therapy of anabolic and antiresorptive agents may produce more effect for the treatment of osteoporosis. However, the combination therapy of anabolic agents and bisphosphonates reports no benefit and even reduced the anabolic effects of anabolic agents. This study aims to assess the effect of combination therapy of anabolic and nonbisphosphonates antiresorptive agents in adults with osteoporosis.

METHODS

Medline, EMBASE, and Cochrane Library were searched from January 1, 1980 to November 1, 2017 for randomized controlled trials (RCTs) of adults with osteoporosis treated in combination therapy of anabolic and nonbisphosphonates antiresorptive agents compared with monotherapy of either agent alone. The primary outcome was the incidence of fractures. The secondary outcomes were the bone mineral density (BMD) changes at lumbar spine and total hip. Continuous outcomes were expressed as standardized mean difference (SMD) and 95% confidence interval (CI), while dichotomous outcomes were expressed as risk ratio (RR) and 95% CI. The meta-analysis was performed using a random-effects model. I statistic (I > 50% as a threshold indicates significant heterogeneity) was used to assess the heterogeneity.

RESULTS

A total of 10 trials with a total of 1042 patients were included. The pooled results showed that the combination therapy demonstrated a significant advantage over a monotherapy in the BMD improvement at the lumbar spine (SMD 1.18; 95% CI, 0.63 to 1.72; I = 93%) and the total hip (SMD 0.89; 95% CI, 0.48 to 1.29; I = 88%) and further reduce the fracture risk (RR, 0.45; 95%CI, 0.21 to 0.94; I = 0%).

CONCLUSIONS

Low-to-moderate-quality evidence shows that the combination therapy of anabolic and nonbisphosphonates antiresorptive agents is superior to monotherapy in improving the BMD and reducing the fracture risk. However, further high methodological quality studies are needed to determine the antifracture efficacy, cost-effectiveness and safety of this strategy of combination therapy.

Anabolic treatment for osteoporosis: teriparatide

Teriparatide is a safe and effective anabolic treatment for osteoporosis. In postmenopausal women, it increases BMD and decreases vertebral fractures by about 70% and non-vertebral fractures by about 45% (although there is no evidence that it prevents hip fractures). The current evidence indicates that it should be administered for a single course of 24 months, and followed with an anti-resorptive agent to maintain the BMD gain. There is no clear benefit to repeated or cyclical treatment. Combination treatment, particularly with denosumab achieves greater BMD increase than either agent alone, but there are no available fracture data for combination treatment. There are some unknowns; most fundamentally why daily PTH administration is anabolic to bone when continuous high PTH is catabolic. Also, a better understanding of why the anabolic action declines with time and why there is a poor response to repeated treatment may help us to use teriparatide more effectively, and increase our understanding of bone biology and osteoporosis pathophysiology.

Improving Combination Osteoporosis Therapy in a Preclinical Model of Heightened Osteoanabolism

Combining anticatabolic agents with parathyroid hormone (PTH) to enhance bone mass has yielded mixed results in osteoporosis patients. Toward the goal of enhancing the efficacy of these regimens, we tested their utility in combination with loss of the transcription factor Nmp4 because disabling this gene amplifies PTH-induced increases in trabecular bone in mice by boosting osteoblast secretory activity. We addressed whether combining a sustained anabolic response with an anticatabolic results in superior bone acquisition compared with PTH monotherapy. Additionally, we inquired whether Nmp4 interferes with anticatabolic efficacy. Wild-type and Nmp4-/- mice were ovariectomized at 12 weeks of age, followed by therapy regimens, administered from 16 to 24 weeks, and included individually or combined PTH, alendronate (ALN), zoledronate (ZOL), and raloxifene (RAL). Anabolic therapeutic efficacy generally corresponded with PTH + RAL = PTH + ZOL > PTH + ALN = PTH > vehicle control. Loss of Nmp4 enhanced femoral trabecular bone increases under PTH + RAL and PTH + ZOL. RAL and ZOL promoted bone restoration, but unexpectedly, loss of Nmp4 boosted RAL-induced increases in femoral trabecular bone. The combination of PTH, RAL, and loss of Nmp4 significantly increased bone marrow osteoprogenitor number, but did not affect adipogenesis or osteoclastogenesis. RAL, but not ZOL, increased osteoprogenitors in both genotypes. Nmp4 status did not influence bone serum marker responses to treatments, but Nmp4-/- mice as a group showed elevated levels of the bone formation marker osteocalcin. We conclude that the heightened osteoanabolism of the Nmp4-/- skeleton enhances the effectiveness of diverse osteoporosis treatments, in part by increasing hyperanabolic osteoprogenitors. Nmp4 provides a promising target pathway for identifying barriers to pharmacologically induced bone formation.

Using Osteoporosis Therapies in Combination

PURPOSE OF REVIEW

The objective of this review is to update evidence regarding the use of osteoporosis drugs in sequence or in combination to optimize increases in bone mass and strength.

RECENT FINDINGS

Simultaneous use of denosumab plus teriparatide produces larger increases in BMD than does monotherapy. The use of bisphosphonates or denosumab after teriparatide results in progressive gains in BMD. When switching from bisphosphonates and especially denosumab to teriparatide, an overlap of 6-12 months may prevent the transient loss of BMD in cortical sites. Phase 3 trials document fracture risk reduction with anabolic therapy for 12-18 months followed by an anti-remodeling drug. With the exception of adding teriparatide to ongoing denosumab therapy, there is little evidence to support the use of more than one osteoporosis drug at a time. In contrast, sequential therapy regimens of anabolic drugs followed by potent anti-remodeling agents will be the new standard for treating patients at imminent risk of fracture.

Parathyroid Hormone and Parathyroid Hormone-Related Protein Analogs in Osteoporosis Therapy

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.

Combined Pharmacologic Therapy in Postmenopausal Osteoporosis

Antiresorptive agents for treating postmenopausal osteoporosis include selective estrogen receptor modulator (SERM), bisphosphonates and denoumab. Teriparatide is the only Food and Drug Administration-approved anabolic agent. Synergistic effects of combining teriparatide with an antiresorptive agent have been proposed and studied. This article reviews the trial designs and the outcomes of combination therapies. Results of the combination therapy for teriparatide and bisphosphonates were mixed; while small increases of bone density were observed in the combination therapy of teriparatide and estrogen/SERM and that of teriparatide and denosumab. Those clinical studies were limited by small sample sizes and lack of fracture outcomes.

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.

Use of combination therapy in the treatment of primary osteoporosis: protocol for a network meta-analysis of randomised trials

INTRODUCTION

The existing medications approved for treatment of primary osteoporosis can be divided into antiresorptive drugs and anabolic drugs. According to the mechanisms of action, the combined therapy may produce a synergistic effect on bone mineral density (BMD) compared with monotherapy, and thus improves the efficacy of fracture resistance. This network meta-analysis aims to compare the efficacies of different combined methods for the treatment of primary osteoporosis.

METHODS AND ANALYSIS

MEDLINE, EMBASE and Cochrane databases will be searched to identify all randomised controlled trials (RCTs) and quasi-RCTs that evaluate the effectiveness of combined therapy versus monotherapy for primary osteoporosis. The primary outcome will be the BMD changes at the lumbar spine and total hip, and the secondary outcome will be the risks of vertebral fracture and non-vertebral fracture. The efficacies of different combined methods will be compared via traditional pairwise meta-analysis, trial sequential analysis and Bayesian network meta-analysis. Risk of bias will be assessed using the Cochrane tool and the quality of evidence will be assessed using the Grading of Recommendations Assessment, Development and Evaluation for network meta-analysis.

ETHICS AND DISSEMINATION

Ethical approval is not required because this is a protocol for a systematic review without including confidential personal data or data on interventions on patients. Our results will be published in a peer-review journal.

TRIAL REGISTRATION NUMBER

PROSPERO CRD42016038569.

Anabolic Therapy for Osteoporosis

Antiresorptive agents for osteoporosis are a cornerstone of therapy, but anabolic drugs have recently increased our options. By directly stimulating bone formation, anabolic agents reduce fracture incidence by improving bone qualities as well as increasing bone mass. The anabolic agent currently approved for osteoporosis, teriparatide (recombinant human parathyroid hormone[1–34]), has emerged as a major approach for selected patients with osteoporosis. Parathyroid hormone(1–84) is also available in Europe. Teriparatide increases bone density and bone turnover, improves microarchitecture and changes bone size. The incidence of vertebral and nonvertebral fractures is reduced. A current concept in the mechanism of teriparatide action is related to its effect of stimulating processes associated with bone formation before processes associated with bone resorption. This sequence of events has led to the concept of the anabolic window, the period of time when teriparatide is maximally anabolic. Newer approaches to the use of teriparatide alone and in combination with antiresorptive agents has led to ways in which the anabolic window can be expanded.

Teriparatide for osteoporosis: importance of the full course

Teriparatide (TPTD) is the only currently available therapeutic agent that increases the formation of new bone tissue and can provide some remediation of the architectural defects in the osteoporotic skeleton. The use of teriparatide clinically is limited to 24 months. We review clinical findings during daily teriparatide treatment over time. Teriparatide appears to increase bone formation more than bone resorption as determined biochemically and histologically. Teriparatide exerts its positive effects on bone formation in two distinct fashions. The first is direct stimulation of bone formation that occurs within active remodeling sites (remodeling-based bone formation) and on surfaces of bone previously inactive (modeling-based bone formation). The second is an increase in the initiation of new remodeling sites. Both processes contribute to the final increase in bone density observed by non-invasive tools such as DXA. Remodeling is the repair process by which skeletal tissue is maintained in a young healthy state, and when stimulated by TPTD is associated with a positive bone balance within each remodeling cavity. It seems likely therefore that this component will contribute to the anti-fracture efficacy of TPTD. Teriparatide reduces the risk of fracture, and this effect appears to increase with longer duration of therapy. The use of novel treatment regimens, including shorter courses, should be held in abeyance until controlled clinical trials are completed to define the relative fracture benefits of such approaches in comparison to the 24-month daily use of the agent. Summary In patients with osteoporosis at high risk for fracture, the full continuous 24-month course with teriparatide results in improved skeletal health and outcomes than shorter time periods.

Italian association of clinical endocrinologists (AME) position statement: drug therapy of osteoporosis

Treatment of osteoporosis is aimed to prevent fragility fractures and to stabilize or increase bone mineral density. Several drugs with different efficacy and safety profiles are available. The long-term therapeutic strategy should be planned, and the initial treatment should be selected according to the individual site-specific fracture risk and the need to give the maximal protection when the fracture risk is highest (i.e. in the late life). The present consensus focused on the strategies for the treatment of postmenopausal osteoporosis taking into consideration all the drugs available for this purpose. A short revision of the literature about treatment of secondary osteoporosis due both to androgen deprivation therapy for prostate cancer and to aromatase inhibitors for breast cancer was also performed. Also premenopausal females and males with osteoporosis are frequently seen in endocrine settings. Finally particular attention was paid to the tailoring of treatment as well as to its duration.

Bone Density After Teriparatide Discontinuation in Premenopausal Idiopathic Osteoporosis

CONTEXT

Without antiresorptive therapy, postmenopausal women lose bone mass after teriparatide (TPTD) discontinuation; estrogen treatment prevents bone loss in this setting. It is not known whether premenopausal women with regular menses lose bone mass after teriparatide discontinuation.

OBJECTIVE

This study aimed to test the hypothesis that normally menstruating premenopausal women with idiopathic osteoporosis (IOP) will maintain teriparatide-associated bone mineral density (BMD) gains after medication cessation.

DESIGN

Twenty-one premenopausal IOP women previously enrolled in an open-label pilot study of teriparatide (20 mcg for 18-24 mo), had substantial BMD increases at the lumbar spine (LS; 10.8 ± 8.3%), total hip (TH; 6.2 ± 5.6%), and femoral neck (7.6 ± 3.4%). For this study, BMD was remeasured 2.0 ± 0.6 years after teriparatide cessation.

PARTICIPANTS

Fifteen women, who had gained 11.1 ± 7.2% at LS and 6.1 ± 6.5% at TH and were premenopausal at teriparatide completion, were followed without antiresorptive treatment.

RESULTS

Two years after completing teriparatide, BMD declined by 4.8 ± 4.3% (P = .0007) at the LS. In contrast, BMD remained stable at the femoral neck (-1.5 ± 4.2%) and TH (-1.1 ± 3.7%). Those who sustained LS bone loss >3% (-7.3 ± 2.9%; n = 10), did not differ from those with stable LS BMD (0.1 ± 1.1%; n=5) with regard to baseline body mass index, BMD at any site, or duration of followup, but were significantly older at re-evaluation (46 ± 3 vs 38 ± 7; P = .046), had larger increases in LS BMD during teriparatide treatment and higher cancellous bone remodeling on transiliac biopsy at baseline and completion of teriparatide treatment. Serum bone turnover markers did not differ at baseline or teriparatide completion, but tended to be higher at the re-evaluation timepoint in those with post-teriparatide bone loss.

CONCLUSIONS

These findings lead us to conclude that premenopausal women with IOP, particularly those over 40, may require antiresorptive treatment to prevent bone loss after teriparatide.

Daily or Cyclical Teriparatide Treatment in Women With Osteoporosis on no Prior Therapy and Women on Alendronate

CONTEXT

Intermittent 3-month cyclic administration might optimize the anabolic potential of teriparatide (TPTD).

OBJECTIVE

To determine whether 3-month cyclical TPTD would produce a similar bone mineral density (BMD) response to daily therapy in treatment naive (Rx-naive) women and to confirm the results in alendronate (ALN)-treated (ALN-Rx) women over 24 months.

DESIGN

Subjects participated in a randomized open-label study for 2 years.

SETTING

Osteoporosis clinical research center.

PARTICIPANTS

A total of 150 postmenopausal women with osteoporosis in two cohorts: 86 Rx-naive and 64 ALN-Rx.

INTERVENTION

Within cohorts, women were randomized to daily TPTD for 24 months or four 3-month TPTD cycles, each followed by 3 months off (12 mo total TPTD).

MAIN OUTCOMES

BMD at 24 months.

RESULTS

In Rx-naive women, BMD increased in the lumbar spine (LS), total hip (TH), trochanter (Troch), and femoral neck (FN) in daily and cyclic groups (within groups, P < .0002, except cyclic FN, P = .13). Increases were 2-fold greater in daily vs cyclic groups (LS, 8.8 vs 4.8%; TH, 4.0 vs 2.1%; Troch, 5.6 vs 3.1%; and FN, 2.9 vs 1.2%; group differences, all P < .05). In daily vs cyclic groups, radius BMD declined (-4.2 vs -2.1%, respectively; both P < .01; group difference, P = .08) and total bone mineral increased modestly (1.4%, P = .18; vs 1.5%, P = .06; group difference, not significant). In ALN-Rx women, there were no group differences (daily vs cyclic: LS, 7.5 and 6.0%; TH, 3 and 2.5%; Troch, 3.7 and 3.3%; FN, 3 and 1.5%; within groups, P < .003; except cyclic FN, P = .2). In daily and cyclic groups, radius BMD decreased (-0.7% [not significant] and -1.4% [P < .05], respectively), and total bone mineral increased 2.3 and 3% (both P < .001).

CONCLUSION

Cyclic TPTD over 2 years improves BMD similarly to daily treatment in women who remain on ALN, despite only 50% of the TPTD dose. However, there does not appear to be a BMD advantage to cyclic administration in treatment-naive women for up to 24 months.

Synergistic effects of high dietary calcium and exogenous parathyroid hormone in promoting osteoblastic bone formation in mice

In the present study, we investigated whether high dietary Ca and exogenous parathyroid hormone 1–34 fragments (PTH 1–34) have synergistic effects on bone formation in adult mice, and explored the related mechanisms. Adult male mice were fed a normal diet, a high-Ca diet, a PTH-treated diet, or a high-Ca diet combined with subcutaneously injected PTH 1–34 (80 μg/kg per d) for 4 weeks. Bone mineral density, trabecular bone volume, osteoblast number, alkaline phosphatase (ALP)- and type I collagen-positive areas, and the expression levels of osteoblastic bone formation-related genes and proteins were increased significantly in mice fed the high-Ca diet, the PTH-treated diet, and, even more dramatically, the high-Ca diet combined with PTH. Osteoclast number and surface and the ratio of receptor activator for nuclear factor-κB ligand (RANKL):osteoprotegerin (OPG) were decreased in the high-Ca diet treatment group, increased in the PTH treatment group, but not in the combined treatment group. Furthermore, third-passage osteoblasts were treated with high Ca (5 mm), PTH 1–34 (10^− 8m) or high Ca combined with PTH 1–34. Osteoblast viability and ALP activity were increased in either the high Ca-treated or PTH-treated cultures and, even more dramatically, in the cultures treated with high Ca plus PTH, with consistent up-regulation of the expression levels of osteoblast proliferation and differentiation-related genes and proteins. These results indicate that dietary Ca and PTH play synergistic roles in promoting osteoblastic bone formation by stimulating osteoblast proliferation and differentiation.

Antiresorptives and anabolic therapy in sequence or combination for postmenopausal osteoporosis

Osteoporosis is a chronic disease which may require treatment for many years and requires not only individual management but often sequential or combination treatments. Monotherapy with antiresorptives is usually the first choice. Sometimes, it is necessary to modify this option for therapeutic failure or for the time of use and risk of side-effects. Due to their different mode of action, therapy with anabolic drugs has increased our options in the treatment of osteoporosis. Postmenopausal women and men with severe and progressive osteoporosis despite antiresorptive treatment ('therapeutic failure') should be evaluated for treatment with an anabolic option. Moreover, anabolic agents are indicated for 18-24 months in patients at high risk. Then, sequential antiresorptive therapy is recommended to maintain drug increases in bone mass and support secondary mineralization of the newly formed bone. Combination therapies of antiresorptives and anabolic agents have shown a significant increase in bone mineral density compared to monotherapies. However, none of the combinations have been studied for the prevention of fractures. Combination therapy may not be recommended because of the possible increase in cost.

Acting on black box warnings requires a GRADE evidence table and an implementation guide: the case of teriparatide

OBJECTIVES

To assess how well do the black box warnings present and communicate evidence in a way that is consistent with evidence-based patient-centered practice, through evaluating the boxed warning on teriparatide-induced osteosarcoma.

STUDY DESIGN AND SETTING

We critically appraised teriparatide black box warning for osteosarcoma by reviewing human and animal studies that were used as basis for the warning. We also evaluated the quality of the evidence using the Grading of Recommendations Assessment, Development and Evaluation framework.

RESULTS

We found that this warning was based on very low-quality evidence that was derived primarily from animal studies. The quality of evidence was rated down because of high risk of bias in addition to inconsistency, indirectness, and imprecision of the estimates. The warning does not provide sufficient guidance for practice like an implementation tool or an evidence profile to clarify the limitations of the evidence.

CONCLUSION

Black box warning for teriparatide-associated osteosarcoma does not explicitly present the quality of evidence, and therefore, it could be of limited use in evidence-based practice. We propose that black box warnings should include an evidence profile and an implementation guide to be more useful in evidence-based patient-centered practice.

Treatment of post-menopausal osteoporosis: beyond bisphosphonates

Osteoporosis is a highly prevalent condition, characterized by compromised bone strength and fragility fractures and with an important associated socio-economic burden. Bisphosphonates are well established as the first line treatment for osteoporosis. However, while randomized control trials have in general demonstrated reasonable anti-fracture efficacy at the spine, they have shown moderate reduction in fracture incidence for non-vertebral sites. Furthermore, oral bisphosphonates are commonly associated with adverse gastrointestinal effects and both oral and parenteral bisphosphonates have been linked with osteonecrosis of the jaw and atypical femoral fracture, two rare but debilitating side effects. In addition, bisphosphonates are not recommended in patients with GFR <35 ml/min/1.73 m(2). Hence, there is a clear requirement for newer agents, which are able to reduce fracture risk further, whilst overcoming the limitations of bisphosphonates. Over the past 20 years, knowledge and a deeper understanding of the various signalling pathways involved in bone remodelling has increased, enabling identification of additional targets for therapy. This review focuses on these newer therapies and includes anti-resorptive agents such as raloxifene and other selective oestrogen receptor modulators, the monoclonal antibody denosumab (which inhibits the RANKL pathway), odanacatib, a cathepsin K inhibitor and the anabolic agents, PTH analogue; PTH (1-34) and anti-sclerostin antibodies (activator of the Wnt pathway). Strontium ranelate will not be reviewed as recent reports highlight concerns surrounding its cardiovascular safety and together with an apparent increased risk of thrombosis, its future use remains uncertain. Some of these agents such as raloxifene, denosumab and teriparatide are already in clinical use whilst others are at varying stages of development. This review will provide an overview of the mechanisms of action of these therapeutic agents on the skeleton and assess their efficacy in osteoporosis and fracture prevention.

Single and combined use of human parathyroid hormone (PTH) (1-34) on areal bone mineral density (aBMD) in postmenopausal women with osteoporosis: evidence based on 9 RCTs

Background

Human parathyroid hormone (PTH) (1-34) or teriparatide (TPTD) is an anabolic agent for osteoporosis. This recombinant protein stimulates positive bone formation balance and bone remodeling. However, when concomitantly used with antiresorptive (AR) agents, previous studies reported conflicting results in their potential additive and synergistic effects on bone metabolism and bone mineral density (BMD). This study aimed to integrate previous evidence to assess the effect of TPTD monotherapy and the additive effect of TPTD on AR agents in postmenopausal women with osteoporosis.

Material/Methods

This meta-analysis identified 9 RCTs from databases. To assess the therapeutic effect on osteoporosis, the weighted mean differences (WMDs) were used to pool the percentage change of BMD along with the 95% confidence intervals (CIs). BMD of 3 skeletal sites, including lumbar spine, total hip, and femoral neck were assessed.

Results

TPTD alone could significantly improve BMD of all 3 skeletal sites compared with placebo, although the effect on the femoral neck was less conclusive. The additive effect of TPTD over hormone replacement therapy (HRT) and denosumab (DEN) agents is evident in all 3 skeletal sites. But TPTD plus Alendronate (ALN) did not demonstrate additive effect in total hip and femoral neck.

Conclusions

TPTD alone could significantly improve BMD of lumbar spine, total hip, and femoral neck. BMD outcomes of concomitant use of TPTD and AR agents are site-dependent and vary depending on the specific AR agent used and the timing of AR therapy initiation.

Anabolic and antiresorptive therapy for osteoporosis: combination and sequential approaches

In the recent Bone Key Reports review, it was noted that combinations of anabolic and antiresorptive agents have potential to improve bone density and bone strength more than either agent as monotherapy. Small clinical trials have been performed evaluating combinations of PTH1-34 (TPTD) or PTH1-84 (PTH) with a variety of antiresorptives including hormone/estrogen therapy, raloxifene, alendronate, risedronate, ibandronate, zoledronic acid, and denosumab. Most of the studies evaluate dual-energy X-ray absorptiometry outcomes, and a few trials report volumetric mineral density (BMD) by quantitative computed tomography, followed by finite element modeling to calculate bone strength. None of the studies has been powered to assess differences in fracture incidence between combination therapy and monotherapy. BMD outcomes vary based on the timing of introduction of the anabolic agent (before, during, or after antiresorptive treatment), as well as the specific anabolic and antiresorptive used. Furthermore, effects of combination therapies are site-dependent. The most consistent effect of combining antiresorptive agents with PTH or TPTD is a superior hip BMD outcome compared with TPTD/PTH alone. This is most evident when TPTD/PTH is combined with a bisphosphonate or denosumab. In contrast to findings in the hip, in the majority of studies, there is no benefit to spine BMD with combination therapy vs monotherapy. The 2 exceptions to this are when TPTD is combined with denosumab and when TPTD is given as monotherapy first for 9 months, followed by the addition of alendronate (with continuation administration of TPTD). Based on what we now know, in patients previously treated with bisphosphonates who suffer hip fractures or who have very low or declining hip BMD, strong consideration should be given to starting TPTD and continuing a potent antiresorptive agent (possibly switching to zoledronic acid or denosumab) to improve hip BMD and strength quickly. Furthermore, in treatment naïve individuals with very severe osteoporosis, such as those with spine and hip fractures, combination therapy with TPTD and denosumab or TPTD followed by combination treatment with a potent bisphosphonate or denosumab should be considered to maximize early increases in BMD throughout the skeleton (Cosman BoneKEy Rep 3, 2014).

Biological agents in management of osteoporosis

Osteoporosis is a skeletal disease associated with an imbalance between formation and resorption, leading to net loss of bone mass, loss of bone microarchitecture, and development of fractures. Bone resorption is primarily due to an activation of osteoclastogenesis and an increase in receptor activator of nuclear factor kappa-B ligand (RANKL) expression, a cytokine involved in the final pathway of the osteoclast cycle.Recent studies of genetic diseases led to the discovery of the wingless-type (Wnt) signaling pathway that plays a major role in bone formation. Further work showed that sclerostin produced by osteocytes and the Dickkopf (DKK1) protein secreted in bone were negative regulators of the Wnt signaling bone formation pathway that act directly by binding to the co-receptors LRP5 and LRP6 of WnT and thereby inhibiting the anabolic Wnt pathway. This understanding of the bone remodeling led to the discovery of new biological drugs that target these pathways and have been evaluated in clinical trials.The current article discusses the role of these newer "biological" agents in management of osteoporosis. Denosumab, a human monoclonal antibody that specifically binds RANKL, blocks the binding of RANK to its ligand markedly reducing bone resorption, increases bone density, and reduces fractures and is approved for osteoporosis. Parathyroid hormone PTH 1-34 (teriparatide) stimulates bone formation through inhibition of sclerostin, DKK1, and frizzled protein; increases BMD; improves microarchitecture; and decreases fractures and is approved for osteoporosis. The anti-sclerostin antibodies (romosozumab, blosozumab) increase bone mass by neutralizing the negative effects of sclerostin on the Wnt signaling pathway. These biologics are being evaluated now in a clinical trial and early data looks promising. Cathepsin K is a proteolytic enzyme that degrades bone matrix and inhibitors such as odanacatib show increasing bone density and perhaps decreased fractures. The potential power of combining these newer antiresorptives with the newer anabolic agents could theoretically increase bone mass rapidly to normal within 1 year and reduce fractures. These newer treatments are revolutionizing the management of osteoporosis.

Overlapping and continued alendronate or raloxifene administration in patients on teriparatide: effects on areal and volumetric bone mineral density--the CONFORS Study

Nine month teriparatide (TPTD) monotherapy followed by co-administration of raloxifene (RAL) or alendronate (ALN) for another nine 9 months resulted in incremental bone mineral density (BMD) increase. The aim of this study was to investigate the effects of continued antiresorptive treatments for 12 months in the extension phase. Postmenopausal women (n = 125) with severe osteoporosis on ongoing TPTD treatment for 9 months were randomized into three open-label groups for another 9 months: ALN (70 mg/week, n = 41), RAL (60 mg/d, n = 37) in addition to TPTD or no additional medication (n = 47) except Ca and vitamin D. After discontinuation of TPTD the respective antiresorptives were continued for a further 12 months, while patients in the TPTD monotherapy group received Ca and vitamin D. Amino-terminal propeptide of type I procollagen (P1NP) and cross-linked C-telopeptide (CTX), areal and volumetric BMD at the lumbar spine (LS) and hip were assessed. ALN resulted in continued BMD increase in LS (4.3 ± 1.5%; mean ± SD), femoral neck (4.2 ± 1.6%) and total hip (4 ± 1.6%; p < 0.001 for all), while RAL was only effective at the LS (2.4 ± 1.7%, p < 0.001) but no changes at the femoral neck (0.4 ± 1.4%) or total hip (-0.8 ± 1.5%) were observed. Cortical bone only increased in the ALN group (femoral neck 6.7 ± 2.7% and -1.3 ± 2.5%; total hip 13.8 ± 2.9% and -2.3 ± 2.5% for ALN and RAL, p < 0.001 for all; respectively). Analyzing the entire 30 months of therapy, the ALN group revealed the largest BMD increase in all regions. Our results suggest that the addition of ALN to ongoing TPTD and continuing ALN after TPTD was stopped may be beneficial for patients in terms of areal and volumetric BMD increase. Further research is warranted to determine the optimal timing of the initiation of the combination treatment, the respective antiresorptive medication and the potential benefit of this BMD increase regarding fracture prevention.

Combination therapy for osteoporosis: a reappraisal

Combinations of anabolic and antiresorptive agents have potential to improve bone density and bone strength more than either agent alone. A large number of relatively small clinical trials have been performed evaluating combinations of PTH1-34 or PTH1-84 with a variety of antiresorptives, including hormone/estrogen therapy, raloxifene, alendronate (Aln), risedronate, ibandronate, zoledronic acid and denosumab (Dmab). Most of the studies evaluate dual-X-ray densitometry outcomes, with a few trials reporting volumetric bone mineral density (BMD) by quantitative computed tomography followed by finite element modeling of bone strength. None of the studies has been powered to assess differences in fracture incidence between combination therapy and monotherapy. BMD outcomes vary depending on the timing of introduction of the anabolic agent (before, during or after antiresorptive treatment), as well as according to the specific anabolic and antiresorptive used. Furthermore, effects of combination therapies are site dependent. The most consistent effect of combining antiresorptive agents with parathyroid hormone (PTH) is a superior hip BMD outcome compared with PTH alone. This is most evident when PTH is combined with a bisphosphonate or Dmab. In contrast to findings in the hip, in the majority of studies there is no benefit to spine BMD with combination therapy when compared with monotherapy. The two exceptions to this are when PTH is combined with Dmab and when PTH is given as monotherapy first for 9 months followed by the addition of Aln and continuation of PTH as combination treatment. On the basis of what we now know, in patients on bisphosphonates who suffer hip fractures or who have very low hip BMD, strong consideration should be given to starting teriparatide and continuing a bisphosphonate (possibly switching to zoledronic acid or even Dmab) to maximize hip BMD and strength. Furthermore, in treatment-naive individuals with very severe osteoporosis, such as those with spine and hip fractures, combination therapy with PTH and Dmab or PTH followed by combination treatment with a potent bisphosphonate or Dmab should be considered to maximize early increases in BMD.

Effects of different dosages of parathyroid hormone-related protein 1-34 on the bone metabolism of the ovariectomized rat model of osteoporosis

Intermittent and low-dose parathyroid hormone (PTH) injection to stimulate bone formation has been used in the treatment of osteoporosis. The N-terminal fragment 1-34 of PTH is quite similar in structure and function to N-terminal PTH-related protein (PTHrP). PTH(1-34) and PTHrP also share a coreceptor, the PTH/PTHrP receptor. Therefore, some studies have suggested that PTHrP could effectively stimulate bone formation, similar to PTH. We used an ovariectomized (OVX) rat model of osteoporosis to study the effects of PTHrP(1-34) on bone metabolism by measuring bone mineral density (BMD), bone histomorphometrics, and biomechanical parameters. We found that subcutaneous injection of PTHrP(1-34) (40 or 80 μg/kg body weight every day) in OVX rats increased lumbar and femoral BMD, improved bone biomechanical properties, enhanced bone strength, and promoted bone formation. We selected 40 μg/kg as the preferred therapeutic dose of PTHrP(1-34) and investigated the effects of frequency of treatment (per 1, 2, 3, or 7 days) on bone metabolism in OVX rats. We found that injection of PTHrP(1-34) once per day or every other day significantly improved the BMD and strength of OVX rats. Serum calcium and phosphate levels in all treated rats did not vary significantly from control rats. Based on our results, intermittent low-dose PTHrP(1-34) injection promoted bone formation in OVX rats, suggesting a high potential for therapeutic use in osteoporosis patients.

Teriparatide for idiopathic osteoporosis in premenopausal women: a pilot study

CONTEXT

Premenopausal women with idiopathic osteoporosis (IOP) have abnormal cortical and trabecular bone microarchitecture.

OBJECTIVE

The purpose of this study was to test the hypotheses that teriparatide increases bone mineral density (BMD) and bone formation and improves trabecular microarchitecture and stiffness in women with IOP.

DESIGN

This was an open-label pilot study.

SETTING

The setting was a tertiary care referral center.

PATIENTS

Participants were 21 premenopausal women with unexplained fragility fractures or low BMD.

INTERVENTION

Teriparatide was administered at 20 μg daily for 18 to 24 months.

MAIN OUTCOME MEASURES

The primary endpoint was within-subject percent change in lumbar spine BMD. Secondary endpoints included percent change in hip and forearm BMD, transiliac biopsy parameters (trabecular bone volume, microarchitecture, stiffness, and adipocytes), serum N-terminal propeptide of procollagen type 1 (P1NP), and C-telopeptide.

RESULTS

BMD increased at the spine (10.8 ± 8.3% [SD]), total hip (6.2 ± 5.6%), and femoral neck (7.6 ± 3.4%) (all P < .001). Serum P1NP doubled by 1 month, peaked at 6 months, and returned to baseline by 18 to 24 months. Transiliac biopsies demonstrated significant increases in cortical width and porosity and trabecular bone volume and number increased, mirrored by a 71% increase in trabecular bone stiffness (P < .02-.001). Adipocyte area, perimeter, and volume/marrow volume decreased, with no change in adipocyte number. Four women had no increase in BMD and a blunted, delayed increase in serum P1NP. Nonresponders had markedly lower baseline bone formation rate (0.002 ± 0.001 vs 0.011 ± 0.006 mm²/mm/y; P < .001) and higher serum IGF-1 (208 ± 54 vs 157± 44 ng/mL; P = .03).

CONCLUSIONS

Teriparatide was associated with increased spine and hip BMD and improved trabecular microarchitecture and stiffness at the iliac crest in the majority of women with IOP.