Anti-vertebral fracture efficacy of raloxifene: a meta-analysis

Refracture following vertebral fragility fracture when bone fragility is not recognized: summarizing findings from comparator arms of randomized clinical trials

PURPOSE

Since vertebral fragility fractures (VFFs) might increase the risk of subsequent fractures, we evaluated the incidence rate and the refracture risk of subsequent vertebral and non-vertebral fragility fractures (nVFFs) in untreated patients with a previous VFF.

METHODS

We systematically searched PubMed, Embase, and Cochrane Library up to February 2022 for randomized clinical trials (RCTs) that analyzed the occurrence of subsequent fractures in untreated patients with prior VFFs. Two authors independently extracted data and appraised the risk of bias in the selected studies. Primary outcomes were subsequent VFFs, while secondary outcomes were further nVFFs. The outcome of refracture within ≥ 2 years after the index fracture was measured as (i) rate, expressed per 100 person-years (PYs), and (ii) risk, expressed in percentage.

RESULTS

Forty RCTs met our inclusion criteria, ranging from medium to high quality. Among untreated patients with prior VFFs, the rate of subsequent VFFs and nVFFs was 12 [95% confidence interval (CI) 9-16] and 6 (95% CI 5-8%) per 100 PYs, respectively. The higher the number of previous VFFs, the higher the incidence. Moreover, the risk of VFFs and nVFFs increased within 2 (16.6% and 8%) and 4 years (35.1% and 17.4%) based on the index VFF.

CONCLUSION

The highest risk of subsequent VFFs or nVFFs was already detected within 2 years following the initial VFF. Thus, prompt interventions should be designed to improve the detection and treatment of VFFs, aiming to reduce the risk of future FFs and properly implement secondary preventive measures.

Combined Thermoneutral Housing and Raloxifene Treatment Improves Trabecular Bone Microarchitecture and Strength in Growing Female Mice

Thermoneutral housing and Raloxifene (RAL) treatment both have potential for improving mechanical and architectural properties of bone. Housing mice within a 30 to 32 °C range improves bone quality by reducing the consequences of cold stress, such as shivering and metabolic energy consumption (Chevalier et al. in Cell Metab 32(4):575-590.e7, 2020; Martin et al. in Endocr Connect 8(11):1455-1467, 2019; Hankenson et al. in Comp Med 68(6):425-438, 2018). Previous work suggests that Raloxifene can enhance bone strength and geometry (Ettinger et al. in Jama 282(7):637-645, 1999; Powell et al. in Bone Rep 12:100246, 2020). An earlier study in our lab utilized long bones to examine the effect of thermoneutral housing and Raloxifene treatment in mice, but no significant interactive effects were found. The lack of an impact is hypothesized to be connected to the short 6-week duration of the study and the type of bone analyzed. This study will examine the same question within the axial skeleton, which has a higher proportion of trabecular bone. After 6 weeks of treatment with RAL, vertebrae from female C57BL/6 J mice underwent microcomputed tomography (μCT), architectural analysis, and compression testing. Most of the tested geometric properties (bone volume/tissue volume percent, trabecular thickness, trabecular number, trabecular spacing) improved with both the housing and RAL treatment. The effect sizes suggested an additive effect when treating mice housed under thermoneutral conditions. While ultimate force was enhanced with the treatment and housing, force normalized by bone volume fraction was not significantly different between groups. For longer pre-clinical trials, it may be important to consider the impacts of temperature on mice to improve the accuracy of these models.

Raloxifene Use After Denosumab Discontinuation Partially Attenuates Bone Loss in the Lumbar Spine in Postmenopausal Osteoporosis

Discontinuation of denosumab (DMab) is associated with decline in bone density. Whether raloxifene can be effective to attenuate bone loss after DMab discontinuation in certain conditions when other antiresorptives cannot be used remains unclear. Data on postmenopausal women with osteoporosis who discontinued DMab treatment after short-term use (1-to-4 doses) at Severance Hospital, Seoul, Korea, between 2017 and 2021 were reviewed. Changes in bone mineral density (BMD) at 12 months after DMab discontinuation was compared between sequential raloxifene users (DR) and those without any sequential antiresorptive (DD) after 1:1 propensity score matching. In matched cohort (66 patients; DR n = 33 vs. DD n = 33), mean age (69.3 ± 8.2 years) and T-score (lumbar spine - 2.2 ± 0.7; total hip - 1.6 ± 0.6) did not differ between two groups at the time of DMab discontinuation. Sequential treatment to raloxifene in DR group attenuated the bone loss in lumbar spine after DMab discontinuation compared to DD group (DR vs. DD; - 2.8% vs. - 5.8%, p = 0.013). The effect of raloxifene on lumbar spine BMD changes remained robust (adjusted β + 2.92 vs. DD, p = 0.009) after adjustment for covariates. BMD loss at femoral neck (- 1.70% vs. - 2.77%, p = 0.673) and total hip (- 1.42% vs. - 1.44%, p = 0.992) did not differ between two groups. Compared to BMD at DMab initiation, DR partially retained BMD gain by DMab treatment in lumbar spine (+ 3.7%, p = 0.003) and femoral neck (+ 2.8%, p = 0.010), whereas DD did not. Raloxifene use after DMab treatment attenuated lumbar spine BMD loss in postmenopausal women with short exposures (< 2 years) to DMab.

Delayed initiation of anti-osteoporosis medications increases subsequent hip and vertebral fractures in patients on long-term glucocorticoid therapy: A nationwide health insurance claims database study in Japan

PURPOSE

Early initiation of anti-osteoporosis medications (AOMs) is recommended for patients on long-term glucocorticoid (GC) therapy. This study aimed to examine whether physicians prescribe AOMs as soon as GC therapy is initiated, and whether a delay in AOM initiation affects hip and vertebral fracture incidence, using the nationwide health insurance claims database of Japan (NDBJ).

METHODS

Patients aged ≥50 years who were prescribed GC (≥5 mg/day prednisolone or equivalent) for ≥90 days and who were followed for AOM use and hip and vertebral fracture events for the subsequent 1080 days in 2012-2018 were selected from NDBJ. Delay in AOM initiation was defined as the number of days without AOMs following GC therapy initiation. Associations between delay in AOM initiation and hip and vertebral fracture risk were evaluated by Cox proportional hazards regression.

RESULTS

In total, 92,143 women and 94,772 men were included in the analysis, of which only 39.3% of women and 28.5% of men received AOMs within 90 days from GC therapy initiation. Approximately, 15% of hip fractures and 30% of vertebral fractures occurred before AOM initiation in patients with delayed AOM initiation. HRs of both fractures were significantly greater in patients with a longer delay in AOM initiation (p value for trend<0.001). After excluding patients who had fractures before AOM initiation, the magnitude of HRs significantly decreased, and HR trends for hip fracture became insignificant.

CONCLUSIONS

Delayed initiation of AOMs may result in increased fracture events, which may be reduced by early initiation of AOMs.

Effects of Raloxifene and tibial loading on bone mass and mechanics in male and female mice

Purpose: Raloxifene (RAL) is a selective estrogen receptor modulator (SERM) that has previously been shown to cause acellular benefits to bone tissue. Due to these improvements, RAL was combined with targeted tibial loading to assess if RAL treatment during periods of active bone formation would allow for further mechanical enhancements.Methods: Structural, mechanical, and microstructural effects were assessed in bone from C57BL/6 mice that were treated with RAL (0.5 mg/kg), tibial loading, or both for 6 weeks, beginning at 10 weeks of age.Results:Ex vivo microcomputed tomography (CT) images indicated RAL and loading work together to improve bone mass and architecture, especially within the cancellous region of males. Increases in cancellous bone volume fraction were heavily driven by increases in trabecular thickness, though there were some effects on trabecular spacing and number. In the cortical regions, RAL and loading both increased cross-sectional area, cortical area, and cortical thickness. Whole-bone mechanical testing primarily indicated the effects of loading. Further characterization through Raman spectroscopy and nanoindentation showed load-based changes in mineralization and micromechanics, while both loading and RAL caused changes in the secondary collagen structure. In contrast to males, in females, there were large load-based effects in the cancellous and cortical regions, resulting in increased whole-bone mechanical properties. RAL had less of an effect on cancellous and cortical architecture, though some effects were still present.Conclusion: RAL and loading work together to impact bone architecture and mechanical integrity, leading to greater improvements than either treatment individually.

The Effects of Osteoporotic and Non-osteoporotic Medications on Fracture Risk and Bone Mineral Density

Osteoporosis is a highly prevalent bone disease affecting more than 37.5 million individuals in the European Union (EU) and the  United States of America (USA). It is characterized by low bone mineral density (BMD), impaired bone quality, and loss of structural and biomechanical properties, resulting in reduced bone strength. An increase in morbidity and mortality is seen in patients with osteoporosis, caused by the approximately 3.5 million new osteoporotic fractures occurring every year in the EU. Currently, different medications are available for the treatment of osteoporosis, including anti-resorptive and osteoanabolic medications. Bisphosphonates, which belong to the anti-resorptive medications, are the standard treatment for osteoporosis based on their positive effects on bone, long-term experience, and low costs. However, not only medications used for the treatment of osteoporosis can affect bone: several other medications are suggested to have an effect on bone as well, especially on fracture risk and BMD. Knowledge about the positive and negative effects of different medications on both fracture risk and BMD is important, as it can contribute to an improvement in osteoporosis prevention and treatment in general, and, even more importantly, to the individual's health. In this review, we therefore discuss the effects of both osteoporotic and non-osteoporotic medications on fracture risk and BMD. In addition, we discuss the underlying mechanisms of action.

Raloxifene in the Treatment of Osteoporosis in Postmenopausal Women with End-Stage Renal Disease: A Systematic Review and Meta-Analysis

As a selective estrogen receptor modulator (SERM), raloxifene is used in healthy postmenopausal women to prevent bone loss and reduce fractures. However, the benefit of raloxifene is uncertain in the treatment of osteoporosis among patients with end-stage renal disease (ESRD) or those who require maintenance dialysis. We assessed the safety and efficacy of raloxifene in this particular population. Studies were selected from PubMed, Springer, CNKI (Chinese National Knowledge Infrastructure) and Wanfang Database. Randomized controlled trials (RCTs) and prospective studies with control/placebo groups were included. Five studies were included with a total of 244 participants (121 patients in the raloxifene group and 123 patients in the placebo/control group). The median duration of treatment was 12 months. The incidence rate of side effects of raloxifene was 0/121 (0%). There was a significant improvement of lumbar spine bone mineral density (BMD) levels in the raloxifene group compared with the placebo group (MD: 33.88, 95% CI: 10.93, 56.84, p=0.004). There was no significant difference concerning the improvement of femoral neck BMD (MD: 8.42, 95% CI: -10.21, 27.04, p=0.38), intact parathyroid hormone (iPTH) (MD: -12.62, 95% CI: -35.36, 10.13, p=0.28), calcium (MD: -0.08, 95% CI: -0.61, 0.44, p=0.76), phosphorus (MD: 0.18, 95% CI: -0.12, 0.48, p=0.23) or bone alkaline phosphatase (BAP) (MD: -4.33, 95% CI: -14.44, 5.79, p=0.40). Raloxifene seems to be effective in improving the lumbar spine BMD in postmenopausal women with ESRD. More large RCTs are necessary to evaluate the long-term safety of raloxifene in uremic patients.

Limited impacts of thermoneutral housing on bone morphology and mechanical properties in growing female mice exposed to external loading and raloxifene treatment

Thermoregulation is an important factor that could have physiological consequences on pre-clinical research outcomes. Simply housing mice at thermoneutral temperature has been shown to prevent the well-established loss of cancellous bone that is typical in growing mice. In this study, active tissue formation was induced by non-invasive tibial loading in female mice and combined with raloxifene treatment to assess whether temperature could enhance their combined effects on bone morphology and mechanical properties. It was hypothesized that by removing the cold stress under which normal lab mice are housed, a metabolic boost would allow for further architectural and mechanical improvements in mice exposed to a combination of tibial loading and raloxifene. Ten-week old female C57BL/6J mice were treated with raloxifene, underwent tibial loading to a maximum tensile stress of 2050 με, and were housed in thermoneutral conditions (32 °C) for 6 weeks. We investigated bone morphology through microcomputed tomography (μCT), mechanical properties via four-point bending, and fracture toughness testing. Results confirmed previous work showing a combined effect of external loading and raloxifene which led to greater improvements in most properties than either individual treatment. Counter to the hypothesis, temperature had modest effects on body weight, overall bone size, and trabecular architecture, and most effects were detrimental. Thermoneutrality had no impact on mechanical integrity or fracture toughness. In most cases, the magnitude of temperature-based effects were less robust than either RAL treatment or loading.

Musculoskeletal Health in Premature Ovarian Insufficiency. Part Two: Bone

Accelerated bone loss and muscle loss coexist in women with premature ovarian insufficiency (POI), but there are significant gaps in our understanding of musculoskeletal health in POI. This review describes estrogen signaling in bone and its role in skeletal health and disease. Possible mechanisms contributing to bone loss in different forms of POI and current evidence regarding the utility of available diagnostic tests and therapeutic options are also discussed. A literature review from January 2000 to March 2020 was conducted to identify relevant studies. Women with POI experience significant deterioration in musculoskeletal health due to the loss of protective effects of estrogen. In bone, loss of bone mineral density (BMD) and compromised bone quality result in increased fracture risk; however, tools to assess bone quality such as trabecular bone score (TBS) need to be validated in this population. Timely initiation of HRT is recommended to minimize the deleterious effects of estrogen deficiency on bone in the absence of contraindications; however, the ideal estrogen replacement regimen remains unknown. POI is associated with compromised bone health, regardless of the etiology. Ongoing research is warranted to refine our management strategies to preserve bone health in women with POI.

6'-Methoxy Raloxifene-analog enhances mouse bone properties with reduced estrogen receptor binding

Raloxifene (RAL) is an FDA-approved drug used to treat osteoporosis in postmenopausal women. RAL suppresses bone loss primarily through its role as a selective estrogen receptor modulator (SERM). This hormonal estrogen therapy promotes unintended side effects, such as hot flashes and increased thrombosis risk, and prevents the drug from being used in some patient populations at-risk for fracture, including children with bone disorders. It has recently been demonstrated that RAL can have significant positive effects on overall bone mechanical properties by binding to collagen and increasing bone tissue hydration in a cell-independent manner. A Raloxifene-Analog (RAL-A) was synthesized by replacing the 6-hydroxyl substituent with 6-methoxy in effort to reduce the compound's binding affinity for estrogen receptors (ER) while maintaining its collagen-binding ability. It was hypothesized that RAL-A would improve the mechanical integrity of bone in a manner similar to RAL, but with reduced estrogen receptor binding. Molecular assessment showed that while RAL-A did reduce ER binding, downstream ER signaling was not completely abolished. In-vitro, RAL-A performed similarly to RAL and had an identical concentration threshold on osteocyte cell proliferation, differentiation, and function. To assess treatment effect in-vivo, wildtype (WT) and heterozygous (OIM+/−) female mice from the Osteogenesis Imperfecta (OI) murine model were treated with either RAL or RAL-A from 8 weeks to 16 weeks of age. There was an untreated control group for each genotype as well. Bone microarchitecture was assessed using microCT, and mechanical behavior was assessed using 3-point bending. Results indicate that both compounds produced analogous gains in tibial trabecular and cortical microarchitecture. While WT mechanical properties were not drastically altered with either treatment, OIM+/− mechanical properties were significantly enhanced, most notably, in post-yield properties including bone toughness. This proof-of-concept study shows promising results and warrants the exploration of additional analog iterations to further reduce ER binding and improve fracture resistance.

Zoledronate and Raloxifene combination therapy enhances material and mechanical properties of diseased mouse bone

Current interventions to reduce skeletal fragility are insufficient at enhancing both the quantity and quality of bone when attempting to improve overall mechanical integrity. Bisphosphonates, such as Zoledronate (ZOL), are used to treat a variety of bone disorders by increasing bone mass to decrease fracture risk, but long-term use has been shown in some settings to compromise bone quality. Alternatively, Raloxifene (RAL) has recently been demonstrated to improve tissue quality and overall mechanical properties in a cell-independent manner by binding to collagen and increasing tissue hydration. We hypothesized that a combination of RAL and ZOL would improve mechanical and material properties of bone more than either monotherapy alone by enhancing both quantity and quality. In this study, wildtype (WT) and heterozygous (OIM+/-) male mice from the Osteogenesis Imperfecta (OI) murine model were treated with either RAL, ZOL, or both from 8 weeks to 16 weeks of age. Using the OIM model allows for investigation of therapeutic effects on a quality-based bone disease. Combination treatment resulted in higher trabecular architecture, cortical mechanical properties, and cortical fracture toughness in diseased mouse bone. Two fracture toughness properties, which are direct measures of the tissue's ability to resist the initiation and propagation of a crack, were significantly improved with combination treatment in OIM+/- compared to control. There was no significant effect on fracture toughness with either monotherapy alone in either genotype. Following the mass-based effects of ZOL, trabecular bone volume fraction was significantly higher with combination treatment in both genotypes. Combination treatment resulted in higher ultimate stress in both genotypes. RAL and combination treatment in OIM+/- also increased resilience compared to the control. In conclusion, this study demonstrates the beneficial effects of using combination drug treatments to increase bone mass while simultaneously improving tissue quality, especially to enhance the mechanical integrity of diseased bone. Combination therapies could be a potential method to improve bone health and combat skeletal fragility on both the microscopic and macroscopic levels.

Long-term oral bisphosphonate use in relation to fracture risk in postmenopausal women with breast cancer: findings from the Women's Health Initiative

OBJECTIVE

The aim of the study was to examine the association of long-term oral bisphosphonate use, compared with short-term use, with fracture risk among postmenopausal women with breast cancer.

METHODS

We studied 887 postmenopausal women who were enrolled to the Women's Health Initiative from 1993 to 1998, diagnosed with breast cancer after enrollment, and reported current oral bisphosphonate use of 2 years or more on a medication inventory administered in 2008 to 2009. The outcome of any clinical fracture was ascertained by self-report on an annual study form; a subset of fractures was confirmed with medical records. Women were followed from completion of the medication inventory until 2014. The association between duration of bisphosphonate use reported on the medication inventory and fracture was estimated using multivariate Cox proportional hazards survival models that compared 4 to 7 years and 8 or more years of bisphosphonate use with 2 to 3 years of use.

RESULTS

On average, women were 76 years of age and were followed for 3.7 (SD 1.1) years. There were 142 clinical fractures. In the multivariate-adjusted analysis for fracture risk factors, 8 or more years of bisphosphonate use was associated with higher risk of fracture compared with 2 to 3 years of use (hazard ratio, 1.67 [95% CI, 1.06-2.62]). There was no significant association of 4 to 7 years of use with fracture.

CONCLUSIONS

Bisphosphonate use of 8 or more years was associated with higher risk of any clinical fracture compared with 2 to 3 years of use. Our findings raise concern about potential harm or decreased effectiveness of long-term bisphosphonate use on fracture risk. The findings warrant confirmatory studies.

Raloxifene: A Selective Estrogen Receptor Modulator for Reducing the Risk of Invasive Breast Cancer in Postmenopausal Women

Raloxifene hydrochloride is a selective estrogen receptor modulator that has antiestrogenic effects on breast and endometrial tissue and estrogenic effects on bone, lipid metabolism and blood clotting. Tamoxifen is the prototypical selective estrogen receptor modulator and reduces the risk of both in situ and invasive breast cancers by half when compared with placebo. The limitations on the use of tamoxifen for breast cancer risk reduction relate to its well-known, but rare, side effects. A number of clinical trials have established the benefit of raloxifene on osteoporosis and fracture. Raloxifene significantly improves serum lipids and serum markers of cardiovascular disease risk, but has no significant effect on the risk of primary coronary events. In several osteoporosis trials and the Raloxifene Use for The Heart (RUTH) trial, raloxifene decreased the risk of estrogen receptor-positive breast cancer by 44–90%. In the Study of Tamoxifen And Raloxifene (STAR) trial, the effect of raloxifene on invasive breast cancer was equivalent to that of tamoxifen, with more favorable effects on uterine malignancy and clotting events. Symptomatic side effects are acceptable. In total, the available data indicate that raloxifene represents an acceptable alternative to tamoxifen for the reduction of the risk of postmenopausal breast cancer in high-risk women. The potential market for a compound shown to reduce the risk of breast cancer in postmenopausal women who are at increased risk for breast cancer is more than 10 million women in the USA alone.

Response of bone turnover markers to raloxifene treatment in postmenopausal women with osteopenia

We used two methods of identifying women who reached the target for raloxifene treatment with bone turnover markers. Both approaches identified women that responded to treatment but did not fully agree and may be complementary.

INTRODUCTION

The change in bone turnover markers (BTMs) in response to osteoporosis therapy can be assessed by a decrease beyond the least significant change (LSC) or below the mean of the reference interval (RI). We compared the performance of these two approaches in women treated with raloxifene.

METHODS

Fifty postmenopausal osteopenic women (age 51-72 years) were randomised to raloxifene or no treatment for 2 years. Blood samples were collected for the measurement of BTM. The LSC for each marker was calculated from the untreated women and the RI obtained from healthy premenopausal women (age 35-40 years). Bone mineral density (BMD) was measured at the spine and hip.

RESULTS

There was a decrease in BTM in response to raloxifene treatment, percentage change at 12 weeks: C terminal telopeptide of type I collagen (CTX) -39 % (95 % CI -48 to -28) and N terminal propeptide of type I procollagen (PINP) -32 % (95 % CI -40 to -23) P < 0.001. The proportion of women classified as responding to treatment using LSC at 12 weeks was as follows: CTX 38 % and PINP 52 % and at 48 weeks CTX 60 % and PINP 65 %. For the RI approach, the proportion of women classified as responding to treatment at 12 weeks was CTX and PINP 38 % and at 48 weeks CTX 40 % and PINP 45 %. There was a significant difference in the change in spine BMD in the raloxifene-treated group compared to the no-treatment group at week 48: difference 0.031 g/cm(2) (95 % CI 0.016 to 0.046, P < 0.001).

CONCLUSIONS

The two approaches identified women that reached the target for treatment using BTM. Both LSC and RI criteria appear useful in identifying treatment response, but the two approaches do not fully overlap and may be complementary.

Evaluation and Treatment of Osteoporosis

As the population ages, the rates of osteoporotic fractures will increase, with postmenopausal women incurring most of these fractures. Diagnosis and treatment of osteoporosis are extremely important. Dual-energy x-ray absorptiometry scan screening is recommended in all women more than 65 years of age or in women aged 50 to 64 years with certain risk factors. Treatment should be considered if osteoporosis is present, there is a history of fragility fracture, or in the setting of osteopenia plus high risk for fracture.

Raloxifene reduces skeletal fractures in an animal model of osteogenesis imperfecta

Osteogenesis imperfecta (OI) is a genetic disease of Type I collagen and collagen-associated pathways that results in brittle bone behavior characterized by fracture and reduced mechanical properties. Based on previous work in our laboratory showing that raloxifene (RAL) can significantly improve bone mechanical properties through non-cellular mechanisms, we hypothesized that raloxifene would improve the mechanical properties of OI bone. In experiment 1, tibiae from female wild type (WT) and homozygous oim mice were subjected to in vitro soaking in RAL followed by mechanical tests. RAL soaking resulted in significantly higher post-yield displacement (+75% in WT, +472% in oim; p<0.004), with no effect on ultimate load or stiffness, in both WT and oim animals. In experiment 2, eight-week old WT and oim male mice were treated for eight weeks with saline vehicle (VEH) or RAL. Endpoint measures included assessment of in vivo skeletal fractures, bone density/geometry and mechanical properties. In vivo skeletal fractures of the femora, assessed by micro CT imaging, were significantly lower in oim-RAL (20%) compared to oim-VEH (48%, p=0.047). RAL led to significantly higher DXA-based BMD (p<0.01) and CT-based trabecular BV/TV in both WT and oim animals compared to those treated with VEH. Fracture toughness of the femora was lower in oim mice compared to WT and improved with RAL in both genotypes. These results suggest that raloxifene reduces the incidence of fracture in this mouse model of oim. Furthermore, they suggest that raloxifene's effects may be the result of both cellular (increased bone mass) and non-cellular (presumably changes in hydration) mechanisms, raising the possibility of using raloxifene, or related compounds, as a new approach for treating bone fragility associated with OI.

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.

Quality of life in Japanese women with postmenopausal osteoporosis treated with raloxifene and vitamin D: post hoc analysis of a postmarketing study

OBJECTIVES

To assess the effect of active vitamin D3 on quality of life (QOL) and pain in raloxifene-treated Japanese women with postmenopausal osteoporosis.

RESEARCH DESIGN AND METHODS

This is a post hoc analysis of a previous prospective postmarketing observational study conducted without a comparator group. This study was conducted in 60 Japanese hospitals from September 2007 to February 2009. We compared changes from baseline in QOL and pain in patients receiving raloxifene plus active vitamin D3 with those in patients receiving raloxifene monotherapy at 8 and 24 weeks after treatment.

CLINICAL TRIAL REGISTRATION

Japan Pharmaceutical Information Center (JapicCTI-070465).

MAIN OUTCOME MEASURES

QOL and pain were assessed using Short Form-8 (SF-8), European Quality of Life Instrument 5 Dimensions (EQ-5D), Japanese Osteoporosis Quality of Life Questionnaire (JOQOL), visual analogue pain scales (VAS pain), and pain frequency scores.

RESULTS

A total of 506 patients were included in the post hoc analysis. Both raloxifene monotherapy (RLX, n = 354) and active vitamin D3 cotreatment (COMBI, n = 152) significantly improved QOL and reduced pain from the baseline at Week 8 and Week 24. The COMBI group had significantly greater improvements in JOQOL total score and activity of daily living (total) domain at Week 24 and last observation carried forward (LOCF) than the RLX group. The COMBI group also had significantly greater improvements in SF-8 domains of general health (at Week 8, Week 24, and LOCF), role physical (at Week 24 and LOCF), and mental health (at LOCF) than the RLX group. The COMBI group also had significantly greater reduction in VAS pain at LOCF than the RLX group (mean [SD]: RLX = -0.99 [2.72], COMBI = -1.54 [2.21], P = 0.042).

CONCLUSIONS

Active vitamin D3 supplementation to raloxifene treatment for 24 weeks may have additional benefits in improving QOL and relieving pain in Japanese women with postmenopausal osteoporosis.

New strategies for osteoporosis patients previously managed with strontium ranelate

The aim of this article is to describe potential alternatives to patients no longer eligible for management with strontium ranelate for osteoporosis according to the recommendations by the European Medicines Agency. A systematic search of Pubmed was done for papers on fracture efficacy of various treatments for osteoporosis, and potential harms especially in terms of cardiovascular events and stroke. The results showed that drugs more efficacious in terms of relative risk reduction of fractures than strontium ranelate were alendronate, risedronate, zoledronate, and denosumab. Raloxifene, as for strontium, may be associated with an increased risk of deep venous thromboembolism and fatal stroke. In terms of cardiovascular events special attention may be given to calcium supplements. Thus, patients at risk of stroke and ischemic cardiac events such as acute myocardial infarction should not use strontium ranelate. Ideally more efficacious drugs in terms of fracture reduction should be used such as alendronate, risedronate, zoledronate or denosumab. Raloxifene may pose a special problem as this too may be associated with an increased risk of fatal strokes. Other less-potent drugs in terms of fracture reduction should only be used if no alternatives are available (ibandronate, pamidronate, clodronate). Parathyroid hormone or analogs may be used for a limited time interval in specially selected patients and needs to be followed up with antiresorptive treatment to prevent loss of the bone gained. However, it should be remembered that no head-to-head comparison studies exist.

Raloxifene preserves phenytoin and sodium valproate induced bone loss by modulating serum estradiol and TGF-β3 content in bone of female mice

Antiepileptic drugs (AEDs)-induced adverse consequences on bone are now well recognized. Despite this, there is limited data on the effect of anti-osteoporotic therapies on AEDs-induced bone loss. We hypothesize that estrogen deprivation following phenytoin (PHT) and sodium valproate (SVP) therapy could lead to adverse bony effects. Both PHT and SVP inhibit human aromatase enzyme and stimulate microsomal catabolism of oestrogens. Estrogen deficiency states are known to reduce the deposition of transforming growth factor-β (TGF-β3), a bone matrix protein, having anti-osteoclastic property. Thus, an attempt was made to investigate the effect of raloxifene, a selective oestrogen receptor modulator, in comparison with calcium and vitamin D3 (CVD) supplementation, on PHT and SVP-induced alterations in bone in mice and to unravel the role of estradiol and TGF-β3 in mediation of bony effects by either AEDs or raloxifene. Further, the effect of raloxifene on seizures and on the antiepileptic efficacy of PHT and SVP was investigated. Swiss strains of female mice were treated with PHT (35 mg/kg, p.o.) and SVP (300 mg/kg, p.o.) for 120 days to induce bone loss as evidenced by reduced bone mineral density (BMD) and altered bone turnover markers (BTMs) in lumbar bones (alkaline phosphatase, tartarate resistant acid phosphatase, hydroxyproline) and urine (calcium). The bone loss was accompanied by reduced serum estradiol levels and bone TGF-β3 content. Preventive and therapeutic treatment with raloxifene ameliorated bony alterations and was more effective than CVD. It also significantly restored estradiol and TGF-β3 levels. Deprived estrogen levels (that in turn reduced lumbar TGF-β3 content) following PHT and SVP, thus, might represent one of the various mechanisms of AEDs-induced bone loss. Raloxifene preserved the bony changes without interfering with antiepileptic efficacy of these drugs, and hence raloxifene could be a potential therapeutic option in the management of PHT and SVP-induced bone disease if clinically approved.

Changes in bone mineral density in uterine cervical cancer patients after radiation therapy

PURPOSE

To prospectively investigate the changes in bone mineral density (BMD) after pelvic radiation therapy in patients with uterine cervical cancer.

METHODS AND MATERIALS

Of 52 cervical cancer patients who received pelvic RT in our university hospital between 2009 and 2011, 46 patients without recurrence and who were followed up for more than 12 months were included in the study. The BMD of the irradiated region and nonirradiated regions, serum estradiol, tartrate-resistant acid phosphatase-5b, and N-terminal cross-linking telopeptide of collagen 1 were measured before, at 3 months after, and at 12 months after RT. The patient cohort was divided into 2 groups according to estradiol level before RT, and the groups were defined as postmenopausal (<40 pg/mL) and premenopausal (≥40 pg/mL).

RESULTS

The mean BMDs within the irradiation field (lumbar vertebra 5) in the postmenopausal and the premenopausal groups were 0.825 and 0.910 g/cm(2) before RT and 0.746 and 0.841 g/cm(2) 12 months after RT, respectively. Significant decreases were observed in both groups (P<.05 and P<.01, respectively). In addition, in the premenopausal group the mean BMDs of the nonirradiated regions at thoracic vertebrae 9-12 and lumbar vertebrae 2-4 were 0.753 and 0.958 g/cm(2) before RT and were significantly decreased to 0.706 and 0.921 g/cm(2) 12 months after RT (P<.01 and P<.05, respectively). Estradiol significantly decreased 3 months after RT, whereas tartrate-resistant acid phosphatase-5b and N-terminal cross-linking telopeptide of collagen 1 continued to increase over time in the premenopausal group.

CONCLUSIONS

A decrease in BMD in the irradiated region after RT was observed within 1 year, regardless of menopausal status. Furthermore, in premenopausal patients, pelvic RT caused a decrease in systemic BMD.

Osteoporosis and treatments in Japan: management for preventing subsequent fractures

Prevalent fractures are major contributors to an increased risk of subsequent fractures, particularly in people with osteoporosis. While many studies have been conducted to assess the incidence of fracture in Japanese people with osteoporosis, far fewer have been conducted to assess the risk of subsequent fractures. This article reviews the morbidity, mortality, and risk of fracture in patients who are at high risk of subsequent fracture in Japan and the current treatment options available for these patients. Osteoporotic fractures in Japan are associated with high morbidity and mortality that result in significant financial and social costs. The rise in the proportion of elderly women in the Japanese population is contributing to a greater proportion of people with osteoporotic fractures and the high cost of osteoporosis. Although hip fractures have a significant effect on costs, a greater proportion of the Japanese population experience vertebral fractures. An increase in the incidence of vertebral fractures is concerning because preexisting vertebral fractures in older patients are associated with an increased risk of subsequent fractures. Hence, there is a clear rationale for pharmacological treatment of patients with prevalent vertebral fractures, or for those who are hospitalized or undergo surgery for osteoporotic fractures. Several pharmacological therapies are now available in Japan for the treatment of patients with osteoporosis. Understanding the consequences of subsequent fractures and the treatment options available for patients at high risk of subsequent fractures may contribute to clinical decision-making and improved outcomes for patients with osteoporosis.

Safety and effectiveness profile of raloxifene in long-term, prospective, postmarketing surveillance

This large-scale postmarketing surveillance of raloxifene (60 mg/day) was conducted to assess the safety and effectiveness of raloxifene for long-term use in postmenopausal Japanese women with osteoporosis. The baseline examination included 6,967 women (mean age, 70.4 years). Participants completed observation after 6, 12, 24, and 36 months of therapy. Adverse drug reactions (ADR) were reported in 776 participants (11.14 %), with a total of 87 serious ADR cases occurring in 76 participants (1.09 %). The most frequently reported ADRs were edema peripheral (45/6,967, 0.65 %) and venous thromboembolism (11/6,967, 0.16 %). Of the 6,967 participants, 2,784 were included in the effectiveness analysis. Lumbar spine bone mineral density (BMD) increased significantly (p < 0.001, paired t test) compared with baseline at 6, 12, 24, and 36 months (2.51 %, 2.85 %, 4.76 %, and 3.51 %, respectively). Significant decreases in serum and urinary cross-linked amino-terminal telopeptide of type I collagen (NTX) and urinary deoxypyridinoline levels from baseline were observed at 3 months, followed by a significant decrease of serum bone alkaline phosphatase at 6 months [p < 0.001 for all comparisons except serum NTX (p = 0.011), Wilcoxon signed-rank test]. Early reductions in the biochemical markers of bone turnover (BTM) observed at 3 months with raloxifene treatment correlated negatively with subsequent increases in lumbar spine BMD at 1 year (r = -0.347, p = 0.008). The incidence of any new clinical fractures within 3 years was 1.18 % (82/6,967 participants). In summary, no new signals in safety were observed in the daily use of raloxifene. Moreover, the effectiveness profile of raloxifene was confirmed in practical use by this large-scale, long-term, postmarketing surveillance.

EMAS clinical guide: selective estrogen receptor modulators for postmenopausal osteoporosis

Osteoporosis and the resulting fractures are major public health issues as the world population is ageing. Various therapies such as bisphosphonates, strontium ranelate and more recently denosumab are available. This clinical guide provides the evidence for the clinical use of selective estrogen modulators (SERMs) in the management of osteoporosis in postmenopausal women.

Consensus statements on osteoporosis diagnosis, prevention, and management in the Philippines

OBJECTIVE

The consensus statements were developed to assist healthcare practitioners in providing optimal care to postmenopausal individuals at risk for osteoporosis and fragility fractures in the local setting.

METHODOLOGY

The Technical Review Committee formed by the Osteoporosis Society of the Philippines Foundation Inc. in cooperation with the Philippine Orthopedic Association drafted, retrieved available published evidence, and appraised important issues on osteoporosis and fragility fractures. The Appraisal of Guidelines Research and Evaluation instrument was used to appraise published guidelines while a systematic way of validating the quality of evidence and the level of recommendation was done using the GRADE system. A multidisciplinary panel of experts and stakeholders in an en banc meeting conferred and approved the recommendations.

RESULTS AND CONCLUSION

There were five key issues on preventive, seven on diagnostic, nine on therapeutic aspects of osteoporosis with four other surgical concerns on fragility fractures. All were approved by a panel of stakeholders through a majority vote. These statements will best inform the clinicians and the specialists including orthopedic surgeons and general care practitioners on issues of postmenopausal Filipino women at risk for osteoporosis and fragility fractures.

Current options for the management of postmenopausal osteoporosis

INTRODUCTION

Osteoporosis is a well-recognized disease with severe consequences if left untreated. The prevention of osteoporosis-associated fractures should include fall prevention, calcium supplementation and life-style advice, as well as pharmacological therapy using agents with proven antifracture efficacy.

AREAS COVERED

This manuscript offers an evidence-based critical assessment of the currently available efficacy data on all new chemical entities that have been granted a marketing authorization for the management of primary osteoporosis in women.

EXPERT OPINION

The availability of new therapeutic agents makes clinical decision making in osteoporosis more complex. Therapeutic decisions should be based on a balance between the benefits and risks of treatment, which must be carefully considered in each particular case, both by the physician and the patient. Indeed, no single agent is appropriate for all patients. Therefore, treatment decisions should be made on a tailor-made basis, taking into account all measures of treatment effect and risk, before making informed judgments about the best individual treatment option.

Risk of femoral shaft and subtrochanteric fractures among users of bisphosphonates and raloxifene

Prior studies have suggested an association between bisphosphonate use and subtrochanteric fractures. This cohort study showed an increased risk of subtrochanteric and femoral shaft fractures both before and after the start of drugs against osteoporosis including bisphosphonates. This may suggest an effect of the underlying disease rather than the drugs used.

INTRODUCTION

The objective of this study is to determine the association between drugs against osteoporosis and the risk of femoral shaft and subtrochanteric fractures. No separation was made between atypical and typical fractures.

METHODS

Nationwide cohort study from Denmark with all users of bisphosphonates and other drugs against osteoporosis between 1996 and 2006 (n = 103,562) as exposed group and three age- and gender-matched controls from the general population (n = 310,683). Adjustments were made for prior fracture, use of systemic hormone therapy, and use of systemic corticosteroids.

RESULTS

After initiation of therapy, an increased risk of subtrochanteric fractures was seen for alendronate (hazard ratio (HR) = 2.41, 95% confidence interval (CI) 1.78-3.27), etidronate (HR = 1.96, 95% CI 1.62-2.36), and clodronate (HR = 20.0, 95% CI 1.94-205), but not for raloxifene (HR = 1.06, 95% CI 0.34-3.32). However, an increased risk of subtrochanteric fractures was also present before the start of alendronate (OR = 2.36, 95% CI 2.05-2.72), etidronate (OR = 3.05, 95% CI 2.59-3.58), clodronate (OR = 10.8, 95% CI 1.14-103), raloxifene (OR = 1.90, 95% CI 1.07-3.40), and strontium ranelate (OR = 2.97, 95% CI 1.07-8.27). Similar trends were seen for femoral shaft fractures and overall fracture risk. After the start of etidronate, no dose-response relationship was present (p for trend, 0.54). For alendronate, a decreasing risk was present with increasing average daily dose (p for trend, <0.01).

CONCLUSIONS

Although an increased risk of femoral shaft and subtrochanteric fractures are seen with the use of several types of bisphosphonates, the increased risk before the start of the drugs may point at an effect of the underlying disease being treated. The increased risk may, thus, perhaps be due to confounding by indication.

Emerging therapeutic opportunities for skeletal restoration

Osteoporosis, a syndrome characterized by thin bones and fractures, has become more prevalent in both women and men. Established therapies for treating this disorder consist primarily of drugs that prevent bone loss, such as the bisphosphonates and selective oestrogen receptor modulators. Although these drugs have been shown to reduce fractures in randomized trials, there is an urgent need for treatments that could lower fracture risk further without additional adverse effects. The introduction of parathyroid hormone (teriparatide), which significantly increases bone mineral density, albeit for a relatively short duration, raised expectations that drugs that stimulate bone formation might cure osteoporosis. After outlining current approaches for treating osteoporosis, this Review focuses on emerging therapeutic opportunities for osteoporosis that are based on recent insights into skeletal physiology. Such novel strategies offer promise not only for reducing age-related bone loss and the associated risk of fractures but also for restoring bone mineral density to healthy levels.

Evidence-based guidelines for the pharmacological treatment of postmenopausal osteoporosis: a consensus document by the Belgian Bone Club

Several drugs are available for the management of postmenopausal osteoporosis. This may, in daily practice, confuse the clinician. This manuscript offers an evidence-based update of previous treatment guidelines, with a critical assessment of the currently available efficacy data on all new chemical entities which were granted a marketing authorization. Osteoporosis is widely recognized as a major public health concern. The availability of new therapeutic agents makes clinical decision-making in osteoporosis more complex. Nation-specific guidelines are needed to take into consideration the specificities of each and every health care environment. The present manuscript is the result of a National Consensus, based on a systematic review and a critical appraisal of the currently available literature. It offers an evidence-based update of previous treatment guidelines, with the aim of providing clinicians with an unbiased assessment of osteoporosis treatment effect.

A meta-analysis of the efficacy of raloxifene on all clinical and vertebral fractures and its dependency on FRAX

INTRODUCTION

Multiple Outcomes of Raloxifene Evaluation (MORE), a placebo controlled phase III study of raloxifene in postmenopausal osteoporosis, showed that both doses tested (60 mg and 120 mg daily) reduced the risk of vertebral fracture. There was no significant effect on non-vertebral fracture.

AIMS

The aim of the present study was to evaluate the distribution of fracture risk assessed at baseline using the FRAX tool in MORE and to determine the efficacy of raloxifene as a function of baseline fracture risk. The effects of raloxifene (60 and 120 mg daily combined) with placebo on the risk of all clinical fractures as well as the risk of morphometric vertebral fracture were examined as a function of baseline fracture risk.

METHODS

Baseline clinical risk factors and BMD were entered in the FRAX model to compute the 10-year probability of major osteoporotic fractures. The interaction between fracture probability and treatment efficacy was examined by Poisson regression.

RESULTS

The 10-year probability of major osteoporotic fractures (with BMD) ranged from 0.9% to 77.2%. The incidence of clinical fractures and morphometric vertebral fractures increased with increasing baseline fracture probabilities. Treatment with raloxifene was associated with an 18% decrease in all clinical fractures compared to placebo treatment (hazard ratio HR=0.82; 95% CI=0.71-0.95; p=0.0063) and a 42% decrease in incident morphometric vertebral fractures (HR=0.58; 95% CI=0.48-0.69; p<0.001). Efficacy was shown over the whole range of fracture probability and the interaction between fracture probability and treatment was not significant. The efficacy or raloxifene on vertebral fracture risk was significantly greater at lower ages. At the 90th percentile of age (75 years) vertebral fracture risk was reduced by 31% irrespective of FRAX probabilities. In contrast at younger ages, efficacy was higher and increased further still with decreasing fracture probability.

CONCLUSION

We conclude that raloxifene (60 and 120 mg doses combined) significantly decreased the risk of all clinical fractures and morphometric fractures in women. Overall, there was no significant interaction between efficacy and fracture probability. In the case of morphometric vertebral fractures efficacy decreased significantly with increasing age.

Use of bisphosphonates and raloxifene and risk of deep venous thromboembolism and pulmonary embolism

SUMMARY

Prior studies have associated raloxifene and strontium ranelate with deep venous thromboembolism and pulmonary embolism. In a cohort study, we observed an increased risk also with the bisphosphonates. However, the increase was present already before the start of bisphosphonates pointing at an effect of the underlying condition.

INTRODUCTION

We seek to study the association between use of drugs against osteoporosis and risk of deep venous thromboembolism (DVT) and pulmonary embolism (PE).

METHODS

Nationwide register-based cohort study from Denmark with all users of bisphosphonates and other drugs against osteoporosis between 1996 and 2006 (n = 103,562) as cases and three age- and gender-matched controls from the general population (n = 310,683).

RESULTS

Before start of a drug against osteoporosis, an increased risk of DVT/PE was present in the crude analysis for alendronate, etidronate, and risedronate. However, upon adjustment, this increase in risk disappeared. Before start of raloxifene, a decreased risk of DVT/PE was present (odds ratio (OR) = 0.53, 95% confidence interval (CI), 0.39-0.71). After start of a drug, alendronate (HR = 1.20, 95% CI, 1.00-1.43), clodronate (HR = 4.06, 95% CI, 1.47-11.2), and etidronate (HR = 1-37, 95% CI, 1.23-1.51) were all associated with an increased risk of DVT/PE, while raloxifene was only borderline, significantly associated with risk of DVT/PE (HR = 1.64, 95% CI, 0.97-2.77). No dose-response relationship was present except for alendronate, where the risk was inversely associated with dose, i.e., the risk of DVT/PE decreased with increasing average daily dose. The HR for DVT/PE was higher with clodronate and etidronate than with alendronate. Alendronate and raloxifene carried the same risk for DVT/PE.

CONCLUSION

Bisphosphonates seem associated with an increased risk of DVT/PE. However, the association does not seem to be causal.

Treating postmenopausal osteoporosis in women at increased risk of fracture - critical appraisal of bazedoxifene: a review

Several categories of drugs to treat osteoporosis exist in the form of bisphosphonates, strontium, parathyroid hormone, and selective estrogen receptor modulators (SERM). Advantages and disadvantages exist for each category as some patients may, for example, not tolerate bisphosphonates for gastrointestinal side effects, and especially in women in whom osteoporosis is frequent, several options for treatment are needed. The objectives of this review were to critically appraise the effects of bazedoxifene on risk of fractures especially in women at high risk of fractures. A systematic literature search was conducted for studies, especially randomized controlled trials with fractures as end-points. Bazedoxifene is a new member of the SERM group. The literature search identified one randomized controlled trial with fractures as end-point. This was a 3-year randomized double-blind placebo controlled trial in which 7492 postmenopausal women aged 55 to 85 years were randomly allocated to 1) bazedoxifene (20 [n = 1886] or 40 [n = 1872] mg/day); 2) raloxifene (60 mg/day, n = 1849); or 3) placebo (n = 1885). The risk of vertebral fractures decreased with both 20 (HR 0.58, 95% CI 0.38 to 0.89) and 40 (HR 0.63, 95% CI 0.42 to 0.96) mg of bazedoxifene per day compared to placebo. There was no reduction in non-vertebral fractures. A subgroup of women with a priori high risk of fractures was identified post hoc. In this subgroup there was a reduction in the risk of non-vertebral fractures with the 20 mg dose of bazedoxifene compared to placebo (HR 0.50, 95% CI 0.28 to 0.90). In the 40 mg bazedoxifene group no significant reduction in non-vertebral fractures was seen in this subgroup (HR 0.70, 95% CI 0.40 to 1.20). In general post-hoc defined subgroup analyses should be interpreted with caution. However, the results indicate that bazedoxifene may be effective in preventing vertebral fractures in postmenopausal women with osteoporosis.

Update on estrogens and the skeleton

CONTEXT

The very clinical trial, the Women's Health Initiative, which definitely established the antifracture efficacy of estrogen therapy, led to the demise of estrogen treatment as a viable, long-term option for prevention of bone loss in postmenopausal women due to the well-publicized adverse effects of estrogen plus progestin therapy on a number of nonskeletal endpoints. Given the diminishing clinical use of estrogen, it is logical to question whether estrogen regulation of bone remains a relevant issue at a clinical or basic research level.

EVIDENCE ACQUISITION

Findings of this update are based on a PubMed search and the author's knowledge of the field.

EVIDENCE SYNTHESIS

Basic and clinical studies on the mechanisms of estrogen effects on bone will continue to provide potential novel drug targets for the prevention and treatment of osteoporosis. At a clinical level, it is clear that even the low levels of estrogen present in postmenopausal women have a significant impact on bone turnover, leading to a more aggressive approach to prevent bone loss in patients with breast cancer on aromatase inhibitors. Conversely, increasing these low estrogen levels with small doses of estrogen may have beneficial skeletal effects in postmenopausal women without adverse effects on reproductive tissues. Finally, the search continues for new selective estrogen receptor modulators with beneficial effects on bone and other tissues.

CONCLUSIONS

Even in the post-WHI era, basic and clinical investigation on estrogen and bone will continue to yield important insights that not only expand our knowledge at a basic level but also impact the health of our aging population.

Developing drugs to treat osteoporosis: lessons learned?

BACKGROUND

Selective estrogen-receptor modulators (SERMs) are drugs that act as estrogen receptor agonists or antagonists depending on the target tissue. Theoretically this class of agents would be an ideal substitute for hormone replacement therapy (HRT), if their effects on the skeleton matched those of estrogen while their actions on other tissues were either neutral or beneficial.

OBJECTIVE

To evaluate a Phase III trial of a new SERM, arzoxefine, for prevention of osteoporosis in younger postmenopausal women.

METHODS/RESULTS

Arzoxifene induced modest but significant increases in bone mineral density versus a control group during 2 years of therapy, with minor adverse events. However, fracture efficacy and other patient-specific outcomes were not evaluated.

CONCLUSION

Despite a positive study of surrogate end points (bone density and biochemical markers of bone turnover), arzoxifene was withdrawn from further FDA evaluation, principally because of long-term side effects and lack of non-vertebral fracture efficacy in the companion Phase III fracture study. Each SERM has a unique profile on bone and other tissues. Regulatory approval of this class of agents may remain problematic for the immediate future.

[Vertebroplasty: 10 years clinical and radiological follow-up]

OBJECTIVES

Ten years follow-up of the first patients treated with percutaneous vertebroplasty.

PATIENT AND METHODS

Eighteen patients were retrospectively reviewed having undergone vertebroplasty in our centre between 1989 and 1998. Eight were treated for angioma, eight for osteoporotic compression and two followed for myeloma. They all underwent clinical and radiological evaluation in 2007 (standard X-rays, CT scan and MRI). These examinations were compared to prior baseline pre- and post-therapeutic images.

RESULTS

Radiological characteristic of cement remained unchanged in the long term and there was no modification of anatomical structures in contact with it. Even if the distribution of cement was asymmetrical there was no fracture of the treated vertebras at distance. Degenerative changes of discs facing the vertebroplasty were not more pronounced than for distant discs. We found no significant signal or density anomaly of disc in contact direct with cement. 38.8 % of the patients presented new fractures (n=30). Seventy percent of the fractures were multiple and contiguous. In the long term, all patients reported improvement of pain after the procedure.

CONCLUSION

In our series, we found a good stability of treatment over time. This study shows the long-term safety of percutaneous acrylic vertebroplasty, in particular harmlessness of cement for bone and discs in contact.

Current and emerging pharmacologic therapies for the management of postmenopausal osteoporosis

Postmenopausal osteoporosis is an asymptomatic skeletal disease that is often underdiagnosed and undertreated. Osteoporotic fractures are associated with substantial morbidity and mortality and impaired quality of life-socially, emotionally, and financially. Considering the growing burden of osteoporotic fractures worldwide, there remains an ongoing need for progress in the diagnosis of osteoporosis, identification of individuals at high fracture risk, and treatment to prevent fractures. Adequate intake of calcium and vitamin D is recommended as baseline therapy for osteoporosis prevention and treatment. Available pharmacological agents for the management of postmenopausal osteoporosis may not be appropriate for all women. Oral bisphosphonates are generally considered first-line therapy for patients with osteoporosis, but their use may be limited by gastrointestinal side effects. Other agents include hormone therapy, the selective estrogen receptor modulator (SERM) raloxifene, salmon calcitonin, teriparatide (human recombinant parathyroid hormone), and strontium ranelate (in some countries). Factors that may contribute to poor compliance and persistence with current osteoporosis therapies include drug intolerance, complexity of dosing regimens, and poor understanding of the relative benefit and risk with treatment. Emerging therapies for postmenopausal osteoporosis include novel SERMs (bazedoxifene, lasofoxifene, ospemifene, arzoxifene) and denosumab. Because SERMs can display mixed functional estrogen receptor agonist or antagonist activity depending on the target tissue, they may confer beneficial effects on bone with limited stimulation of other tissues (e.g., breast, endometrium). Clinical investigation of these promising new agents is ongoing to evaluate efficacy and safety, with the goal of developing effective strategies to maximize long-term tolerance, compliance, and persistence with therapy.

Undertreatment of menopausal symptoms and novel options for comprehensive management

OBJECTIVE

There is currently a gap in treatment options for menopausal symptoms and a need for comprehensive therapies that are safe and effective for postmenopausal women. This review discusses challenges in the management of menopausal symptoms and the effect of the Women's Health Initiative (WHI) study findings on current treatment patterns. It also examines present and future therapies.

RESEARCH DESIGN AND METHODS

A literature search was conducted using Medline, the Cochrane Database, and the National Heart Lung and Blood Institute WHI website with the following search terms: primary care, menopause, vasomotor symptoms, hormone therapy, osteoporosis, and vaginal atrophy. Searches were limited to articles published between 1995 and 2009.

RESULTS

Comprehensive therapies that target several aspects of menopause, such as vasomotor symptoms and chronic disease prevention, are currently hormone based. These hormone-based approaches are considered more effective than currently available nonhormonal therapies for the relief of menopausal symptoms. However, hormone therapy is not recommended for women at high risk for venous thromboembolic events, cardiovascular disease, and/or breast cancer. A need exists for novel therapies that mitigate menopausal symptoms, provide protection from osteoporosis, and encourage patient compliance without promoting cancer, heart disease, or stroke. Emerging modalities and strategies, such as the tissue selective estrogen complex (TSEC), Org 50081, MF101, and desvenlafaxine, may provide improved options for postmenopausal women.

CONCLUSIONS

Several new menopausal therapies that may help to address the ongoing unmet need for safe and effective therapies for postmenopausal women are currently in development. In particular, the TSEC, which provides the benefits of both a selective estrogen receptor modulator and conjugated estrogens with an improved tolerability profile, may offer advantages over currently available treatment options. Limitations of this review include the narrow search criteria and limited search period.

Managing the risk of invasive breast cancer in women at risk for breast cancer and osteoporosis: the role of raloxifene

Raloxifene hydrochloride is a selective estrogen receptor modulator (SERM) that has antiestrogenic effects on breast and endometrial tissue and estrogenic effects on bone, lipid metabolism, and blood clotting. Raloxifene significantly improves serum lipids and serum markers of cardiovascular disease risk, but it has no significant effect on the risk of primary coronary events. A meta-analysis of randomized, double-blind, placebo-controlled trials of raloxifene for osteoporosis showed the odds of fracture risk were 0.60 (95% confidence interval [CI] = 0.49–0.74) for raloxifene 60 mg/day compared with placebo. During 8 years of follow-up in an osteoporosis trial, the raloxifene group had a 76% reduction in the incidence of invasive ER-positive breast cancer compared with the placebo group. In the STAR trial, the incidence of invasive breast cancer was 4.30 per 1000 women-years with raloxifene and 4.41 per 1000 with tamoxifen; RR = 1.02; 95% CI, 0.82–1.28. The effect of raloxifene on invasive breast cancer was, therefore, equivalent to that of tamoxifen with more favorable rates of adverse effects including uterine malignancy and clotting events. Millions of postmenopausal women could derive net benefit from raloxifene through reduced rates of fracture and invasive breast cancer.

The NSABP Study of Tamoxifen and Raloxifene (STAR) trial

In the Study of Tamoxifen and Raloxifene (STAR) trial, postmenopausal women at increased risk of breast cancer received either oral tamoxifen (20 mg/day) or raloxifene (60 mg/day) over 5 years. There were an equal number of cases of invasive breast cancer in women assigned to tamoxifen and raloxifene. There were fewer cases of noninvasive breast cancer in the tamoxifen group than in the raloxifene group (risk ratio [RR]: 1.40; 95% confidence interval [CI]: 0.98-2.02). There were more cases of uterine cancer with tamoxifen than with raloxifene (RR: 0.62; 95% CI: 0.35-1.08). Thromboembolic events occurred less often in the raloxifene group (RR: 0.70; 95% CI: 0.54-0.91) and there were fewer cataracts and cataract surgeries in the women taking raloxifene (RR: 0.79; 95% CI: 0.68-0.92). The STAR trial has shown that raloxifene is as effective as tamoxifen in reducing the risk of invasive breast cancer and has a lower risk of adverse events but a nonstatistically significant higher risk of noninvasive breast cancer. The risk of other cancers, fractures, ischemic heart disease and stroke is similar for both drugs.

The ovariectomized, mature rat model of postmenopausal osteoporosis: an assessment of the bone sparing effects of curcumin

Identification of natural health products that might benefit skeletal health could reduce the negative impact of osteoporotic bone fractures upon society. The objectives of this study were to evaluate an animal model of postmenopausal osteoporosis and to search for evidence that curcumin reduces bone mineral losses in a dose-dependent manner when endogenous estrogen levels are reduced. Bone mineral density was measured at the spine, femur and whole body before and at 2, 4 and 6 months after ovariectomy in each of 40 mature rats. Serum osteocalcin and C-telopeptide were measured as indicators of bone formation and resorption rates. Femoral compressive strength was measured at 6 months. Ovariectomy alone resulted in loss of mineral from the spine (p<0.005) and an increase in osteocalcin levels (p<0.05). At the same time, there was an increase in energy to fracture (p<0.01) due to an increased bone size. When ovariectomized animals were given etidronate there was no loss of mineral from the spine, the size of the femur increased (p<0.005), C-telopeptide levels were reduced (p<0.001) and femoral compressive strength increased (p<0.025). Administration of curcumin to ovariectomized animals resulted in changes that were intermediate between those produced by etidronate and by ovariectomy alone. The increase in femur size produced by the highest dose of curcumin was statistically significant (p< 0.01) and curcumin administration resulted in a significant, dose dependent, increase in energy to fracture. Curcumin produces beneficial changes in bone turnover and increases in bone strength using the ovariectomized mature rat model of postmenopausal osteoporosis.

Sex hormones, their receptors and bone health

Sex steroids regulate skeletal maturation and preservation in both men and women, as already recognized in the 1940s by Albright and Reifenstein. The impact of gonadal insufficiency on skeletal integrity has been widely recognized in adult men and women ever since. In the context of their skeletal actions, androgens and estrogens are no longer considered as just male and female hormones, respectively. Androgens can be converted into estrogens within the gonads and peripheral tissues and both are present in men and women, albeit in different concentrations. In the late 1980s, sex steroid receptors were discovered in bone cells. However, the understanding of sex steroid receptor activation and translation into biological skeletal actions is still incomplete. Due to the complex metabolism, sex steroids may have not only endocrine but also paracrine and/or autocrine actions. Also, circulating sex steroid concentrations do not necessarily reflect their biological activity due to strong binding to sex hormone binding globulin (SHBG). Finally, sex steroid signaling may include genomic and non-genomic effects in bone and non-bone cells. This review will focus on our current understanding of gonadal steroid metabolism, receptor activation, and their most relevant cellular and biological actions on bone.