Efficacy of bazedoxifene in reducing new vertebral fracture risk in postmenopausal women with osteoporosis: results from a 3-year, randomized, placebo-, and active-controlled clinical trial

Endometrial safety: a key hurdle for selective estrogen receptor modulators in development

Selective estrogen receptor modulators (SERMs) have the ability to provide mixed functional estrogen receptor (ER) agonist or antagonist activity, depending on the target tissue. Tamoxifen, the first SERM available for clinical use, is regarded as a highly effective agent for the prevention and treatment of breast cancer. However, tamoxifen exhibits ER agonist activity in the uterus and is associated with an increased risk of endometrial hyperplasia and malignancy. Endometrial safety has been an important consideration in the clinical development of SERMs, with improved benefit-risk profiles. Raloxifene, which is currently approved for the prevention and treatment of postmenopausal osteoporosis and for the prevention of breast cancer, seems to have neutral effects on the uterus. Promising results have been observed with the targeted development of newer and more tissue-specific SERMs, many of which are under investigation for postmenopausal osteoporosis. Of the newer SERMs in development, lasofoxifene has been shown to reduce fracture risk and decrease the incidence of breast cancer but has been associated with an increased incidence of vaginal bleeding, endometrial thickening, and endometrial polyps. Lasofoxifene and ospemifene have shown beneficial effects on the vaginal epithelium. Phase 3 clinical data have shown that bazedoxifene is effective in preventing and treating postmenopausal osteoporosis, without adverse effects on the endometrium or breast. Arzoxifene has been evaluated in phase 3 trials for postmenopausal osteoporosis and has been studied for the treatment of uterine malignancies but is no longer in clinical development. Further investigation of newer SERMs is warranted to more clearly define the endometrial safety of these agents.

FRAX and its applications in health economics--cost-effectiveness and intervention thresholds using bazedoxifene in a Swedish setting as an example

BACKGROUND

An important aspect of cost-effectiveness analysis of osteoporosis is to accurately model the fracture risk and mortality related to the patient groups in the analysis. The estimation of fracture risk is based on a number of factors, such as the level of general risk of the normal population, the effect of treatment and the prevalence of clinical risk factors (CRFs) for fracture. Fracture risk has traditionally been calculated with risk adjustments based on age, bone mineral density and prior vertebral fracture. The treatment effect has been derived from clinical trials and, in the absence of subgroup analyses, the same efficacy has been assumed irrespective of the fracture risk of the population. The FRAX tool enables the estimation of risk based on a wider range of risk factors, and treatment efficacy that is dependent on the level of risk in the analyzed population. The objective was to describe the implementation of the FRAX algorithms into health economic osteoporosis models and to highlight how it differs from traditional risk assessment.

METHODS

The selective estrogen receptor modulator, bazedoxifene, was evaluated in a Swedish setting with traditional and FRAX-based risk assessment in a previously developed Markov model that included fractures and thromboembolic events, and also was adapted to accommodate risk-dependent efficacy, which is available for bazedoxifene.

RESULTS

The traditional approach gave lower ICERs at ages up to 60 years compared to the FRAX method when only considering age, BMD and prior fracture. At 70 years and older and when adding more CRFs with the FRAX approach, the FRAX ICER decreased and fell below the traditional approach. The risk dependant efficacy was the main reason for lower ICERs with FRAX in women at higher risk of fracture.

DISCUSSION

FRAX applied in cost-effectiveness analyses is a more granular method for the estimation of fracture risk, mortality and efficacy compared to previous approaches that can also improve case finding. Furthermore, it facilitates the estimation of cost-effectiveness for various types of patients with different combinations of CRFs, which more closely matches patients in clinical practice.

Current, new and future treatments of osteoporosis

Osteoporosis as a common chronic disease is challenging human health. Although different therapeutic options are routinely used for prevention/treatment of osteoporosis, their side effects and benefits are under question. Increasing our knowledge about signaling pathways in bone and osteocytes as well as osteoblasts and osteoclasts will help us in designing new therapeutic modalities for osteoporosis. In the present study, all new therapeutic measures of osteoporosis have been reviewed. For this purpose, search engines like Pubmed, Web of Science, Scopus, Google Scholar were searched and all relevant articles were found. The study was limited to the year 1998-2010. Bisphosphonates are the cornerstone of osteoporosis treatment, but there are not enough relevant studies that investigated their equivalencies in comparison with each other or the other medications. Therefore, medication selection is empirical and subjective. Furthermore, no eminent study has compared certain combinations. There are new hopes for treatment of osteoporosis, which are more specific with less harm. Our results show that new and emerging therapies are more potent and target specified which more individualize osteoporosis treatment; however, more investigations on their safety and efficacy in comparison with current medications are highly recommended.

Efficacy and safety of bazedoxifene, a novel selective estrogen receptor modulator for the prevention and treatment of postmenopausal osteoporosis

OBJECTIVE

Osteoporosis affects millions of individuals, particularly postmenopausal women, and imposes a severe burden on patients and the healthcare system. Several therapeutic options are commercially available for the prevention and treatment of osteoporosis, including bisphosphonates, hormone therapy, and the selective estrogen receptor modulator (SERM), raloxifene. Because each of these agents has its own individual risk-benefit profile, their use should be tailored to specific patient populations. While many agents are approved for osteoporosis, new therapies are needed that maximize efficacy outcomes and minimize safety concerns. Several new SERMs are being evaluated in an effort to achieve an ideal tissue selectivity profile, with beneficial effects on bone without negative effects on the endometrium and breast. Bazedoxifene is a novel SERM that was recently approved in the European Union and is undergoing regulatory review in the United States for the prevention and treatment of postmenopausal osteoporosis. This article reviews the clinical efficacy and safety data for bazedoxifene in postmenopausal women with or at risk for osteoporosis.

METHODS

The PubMed database and relevant congress abstract databases were searched to identify all pertinent literature on bazedoxifene for the prevention and/or treatment of postmenopausal osteoporosis.

RESULTS

In phase 3 clinical studies, bazedoxifene has demonstrated significant reduction in the risk of new vertebral fracture versus placebo and positive effects on bone mineral density and bone turnover. Moreover, in a subgroup analysis of women at high risk for fracture, bazedoxifene significantly reduced the risk of nonvertebral fracture versus both placebo and raloxifene. Bazedoxifene was generally safe and well-tolerated in women with and at risk for osteoporosis, with no evidence of endometrial or breast stimulation. Data inclusion for this review article was limited by what was available in the public domain.

CONCLUSION

The available clinical data suggest that bazedoxifene may offer a favorable risk-benefit profile for the prevention and treatment of postmenopausal osteoporosis.

Safety of bazedoxifene in a randomized, double-blind, placebo- and active-controlled Phase 3 study of postmenopausal women with osteoporosis

Background

We report the safety findings from a 3-year phase 3 study (NCT00205777) of bazedoxifene, a novel selective estrogen receptor modulator under development for the prevention and treatment of postmenopausal osteoporosis.

Methods

Healthy postmenopausal osteoporotic women (N = 7,492; mean age, 66.4 years) were randomized to daily doses of bazedoxifene 20 or 40 mg, raloxifene 60 mg, or placebo for 3 years. Safety and tolerability were assessed by adverse event (AE) reporting and routine physical, gynecologic, and breast examination.

Results

Overall, the incidence of AEs, serious AEs, and discontinuations due to AEs in the bazedoxifene groups was not different from that seen in the placebo group. The incidence of hot flushes and leg cramps was higher with bazedoxifene or raloxifene compared with placebo. The rates of cardiac disorders and cerebrovascular events were low and evenly distributed among groups. Venous thromboembolic events, primarily deep vein thromboses, were more frequently reported in the active treatment groups compared with the placebo group; rates were similar with bazedoxifene and raloxifene. Bazedoxifene showed a neutral effect on the breast and an excellent endometrial safety profile. The incidence of fibrocystic breast disease was lower with bazedoxifene 20 and 40 mg versus raloxifene or placebo. Reductions in total and low-density lipoprotein levels and increases in high-density lipoprotein levels were seen with bazedoxifene versus placebo; similar results were seen with raloxifene. Triglyceride levels were similar among groups.

Conclusion

Bazedoxifene showed a favorable safety and tolerability profile in women with postmenopausal osteoporosis.

Trial Registration

Trial registration number: NCT00205777; Trial registration date: September 16, 2005

Management of osteoporosis in postmenopausal women: 2010 position statement of The North American Menopause Society

OBJECTIVE

To update the evidence-based position statement published by The North American Menopause Society (NAMS) in 2006 regarding the management of osteoporosis in postmenopausal women.

METHODS

NAMS followed the general principles established for evidence-based guidelines to create this updated document. A panel of clinicians and researchers expert in the field of metabolic bone diseases and/or women's health was enlisted to review the 2006 NAMS position statement, compile supporting statements, and reach consensus on recommendations. The panel's recommendations were reviewed and approved by the NAMS Board of Trustees.

RESULTS

Osteoporosis, which is especially prevalent among older postmenopausal women, increases the risk of fractures. Hip and spine fractures are associated with particularly high morbidity and mortality in this population. Given the health implications of osteoporotic fractures, the primary goal of osteoporosis therapy is to prevent fractures, which is accomplished by slowing or stopping bone loss, maintaining bone strength, and minimizing or eliminating factors that may contribute to fractures. The evaluation of postmenopausal women for osteoporosis risk requires a medical history, physical examination, and diagnostic tests. Major risk factors for postmenopausal osteoporosis (as defined by bone mineral density) include advanced age, genetics, lifestyle factors (such as low calcium and vitamin D intake, smoking), thinness, and menopause status. The most common risk factors for osteoporotic fracture are advanced age, low bone mineral density, and previous fracture as an adult. Management focuses first on nonpharmacologic measures, such as a balanced diet, adequate calcium and vitamin D intake, adequate exercise, smoking cessation, avoidance of excessive alcohol intake, and fall prevention. If pharmacologic therapy is indicated, government-approved options are bisphosphonates, selective estrogen-receptor modulators, parathyroid hormone, estrogens, and calcitonin.

CONCLUSIONS

Management strategies for postmenopausal women involve identifying those at risk for fracture, followed by instituting measures that focus on reducing modifiable risk factors through dietary and lifestyle changes and, if indicated, pharmacologic therapy.

Effects of bazedoxifene/conjugated estrogens on quality of life in postmenopausal women with symptoms of vulvar/vaginal atrophy

OBJECTIVE

To evaluate the effects of the tissue selective estrogen complex (TSEC) pairing bazedoxifene (BZA) with conjugated estrogens (CE) on sexual function and quality of life in postmenopausal women.

METHODS

In this 12-week, double-blind, placebo-controlled study, postmenopausal, non-hysterectomized women (n = 652) with symptoms of moderate to severe vulvar/vaginal atrophy were randomized to once-daily treatment with BZA 20 mg/CE 0.45 or 0.625 mg, BZA 20 mg, or placebo. The Arizona Sexual Experiences (ASEX) Scale, Menopause-Specific Quality of Life (MENQOL) questionnaire, and Menopause Symptoms Treatment Satisfaction Questionnaire (MS-TSQ) were secondary measures used to assess the effects of BZA/CE on sexual function, menopausal symptoms, and satisfaction with treatment, respectively.

RESULTS

At week 12, both BZA/CE doses were associated with significant improvement in ease of lubrication score from baseline compared with placebo (p < 0.05) on the ASEX scale, although there was no difference in the change in total score. The MENQOL questionnaire results at week 12 showed significant improvements in vasomotor function, sexual function and total scores with both BZA/CE doses vs. placebo or BZA 20 mg (p < 0.001). The MS-TSQ results showed that BZA/CE-treated subjects reported significantly greater overall satisfaction with treatment, as well as satisfaction with control of hot flushes during the day and night, effect on quality of sleep, and effect on mood or emotions, compared with subjects treated with placebo or BZA 20 mg (all p < 0.05).

CONCLUSION

Treatment with BZA/CE for 12 weeks was shown to significantly improve sexual function and quality-of-life measures in symptomatic postmenopausal women.

Denosumab--an emerging treatment for postmenopausal osteoporosis

IMPORTANCE OF THE FIELD

Osteoporosis is a common skeletal disease that is associated with an imbalance in bone remodeling. Denosumab is an investigational fully human monoclonal antibody to receptor activator of NF-kappaB ligand (RANKL), a cytokine member of the TNF family that is the principal mediator of osteoclastic bone resorption.

AREAS COVERED IN THIS REVIEW

The efficacy and safety of denosumab in the management of postmenopausal osteoporosis is evaluated by reviewing the published literature and presentations at scientific meetings through 2009.

WHAT THE READER WILL GAIN

This review focuses on the data on fracture risk reduction and safety endpoints of denosumab in the treatment of postmenopausal osteoporosis.

TAKE HOME MESSAGE

In postmenopausal women with osteoporosis, denosumab (60 mg by subcutaneous injection every 6 months) increased bone mineral density, reduced bone turnover markers, and reduced the risk of vertebral, hip and non-vertebral fractures. Denosumab was well tolerated with a safety profile generally similar to placebo. It is a promising emerging drug for the prevention and treatment of postmenopausal osteoporosis.

SERMs in the prevention and treatment of postmenopausal osteoporosis: an update

Selective estrogen receptor modulators (SERMs) have the ability to bind the estrogen receptor (ER) and are known to confer ER agonist or antagonist effects depending on the target tissue. A number of newer SERMs, including bazedoxifene, lasofoxifene and ospemifene, are currently under clinical development for the prevention and treatment of postmenopausal osteoporosis and for other indications. Although the possibility of developing a single agent that has all of the desired characteristics of an ideal SERM seems to be unlikely, progress in the clinical development of SERMs targeted to the ER suggests that these newer compounds may have attributes that represent an improvement relative to existing SERMs. A new approach to menopausal therapy is the tissue selective estrogen complex or the pairing of a selective estrogen receptor modulator with estrogens. Further investigation will help to clarify relative benefits/risks of novel SERMs in development within specific indications.

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.

Bazedoxifene, a selective estrogen receptor modulator: effects on the endometrium, ovaries, and breast from a randomized controlled trial in osteoporotic postmenopausal women

OBJECTIVE

The aim of this study was to evaluate the endometrial, ovarian, and breast safety of bazedoxifene used as a treatment for postmenopausal osteoporosis.

METHODS

Healthy women (aged 55-85 y) with osteoporosis were enrolled in a randomized, double-blind, placebo-controlled phase 3 trial. Participants were randomized to treatment with bazedoxifene 20 or 40 mg, raloxifene 60 mg, or placebo daily for 3 years. Endometrial and ovarian safety was assessed by periodic transvaginal ultrasonography and endometrial biopsy through 24 months. Gynecologic and breast-related adverse events were recorded throughout the study.

RESULTS

Among 753 participants with available transvaginal ultrasonography data, there were no significant between-group differences in overall endometrial thickness or in the percentage of participants with endometrial thickness greater than 5 mm at 12 or 24 months. Changes in the mean endometrial thickness (+/-SE) from baseline were -0.07 +/- 0.11 mm (bazedoxifene 20 mg), 0.10 +/- 0.11 mm (bazedoxifene 40 mg), 0.16 +/- 0.12 mm (raloxifene 60 mg), and -0.08 +/- 0.11 mm (placebo) at 24 months. There was one report of endometrial hyperplasia in each group, and there were zero, two, two, and three reports of endometrial carcinoma with bazedoxifene 20 and 40 mg, raloxifene 60 mg, and placebo, respectively. There were no clinically important changes from baseline in the number or size of ovarian cysts among groups. There was a significantly lower incidence of fibrocystic breast disease (P <or= 0.05) with bazedoxifene compared with raloxifene 60 mg.

CONCLUSION

Bazedoxifene was associated with a favorable endometrial, ovarian, and breast safety profile in postmenopausal women with osteoporosis.

Relief of vasomotor symptoms with the tissue-selective estrogen complex containing bazedoxifene/conjugated estrogens: a randomized, controlled trial

OBJECTIVE

The aim of this study was to assess the safety and efficacy of bazedoxifene (BZA)/conjugated estrogens (CE) treating moderate to severe vasomotor symptoms in the Selective Estrogen Menopause and Response to Therapy 2 trial.

METHODS

This was an outpatient, multicenter, double-blind, randomized, placebo-controlled, phase 3 study conducted in the United States. Healthy postmenopausal women (N = 332; aged 40-65 y) with moderate to severe hot flushes (>or=7/d or 50/wk) were randomized to BZA 20 mg/CE 0.45 mg, BZA 20 mg/CE 0.625 mg, or placebo once daily for 12 weeks. Changes from baseline in the average daily number of moderate and severe hot flushes and daily severity score were assessed at weeks 4 and 12; adverse events were recorded.

RESULTS

BZA/CE significantly reduced the number and severity of hot flushes at weeks 4 and 12 (P < 0.001). At week 12, BZA 20 mg/CE 0.45 mg and BZA 20 mg/CE 0.625 mg reduced hot flushes from baseline by 74% (10.3 hot flushes [baseline] vs 2.8 [week 12]) and 80% (10.4 vs 2.4), respectively, compared with 51% (10.5 vs 5.4) for placebo. More participants at week 12 had at least a 75% decrease in hot flushes with BZA 20 mg/CE 0.45 mg (61%) and BZA 20 mg/CE 0.625 mg (73%) versus placebo (27%; P < 0.001). The safety profile was similar between BZA/CE and placebo, and no unexpected safety findings were reported.

CONCLUSIONS

BZA 20 mg paired with CE 0.45 or 0.625 mg is effective, with short-term safety, for treating vasomotor symptoms in postmenopausal women.

Update on monthly oral bisphosphonate therapy for the treatment of osteoporosis: focus on ibandronate 150 mg and risedronate 150 mg

BACKGROUND

Patient adherence to daily and weekly bisphosphonate treatments is poor and adversely affects their clinical outcome. To increase compliance, bisphosphonate therapies with longer dose-free intervals, such as oral once monthly, were developed.

METHODS

The aim of this review is to provide a summary of the efficacy and safety of the two once-monthly oral bisphosphonates, ibandronate 150 mg and risedronate 150 mg. Fracture trials were initially performed with daily formulations, then bridging trials, in which the efficacy of intermittent dosing was assessed versus daily using validated surrogate endpoints for fracture. Two literature searches were carried out using the MEDLINE and BIOSIS online scientific citation database of published, peer-reviewed manuscripts up to and including December 2008.

FINDINGS

The relative risk reduction (RRR) of new vertebral fractures with risedronate 5 mg daily was 41% (p = 0.003), and 49% (p < 0.001) versus placebo after 3 years in two Phase III studies. In patients at risk of incident fracture, the relative risk of non-vertebral fractures was significantly reduced by 39% (p = 0.02) with 5 mg risedronate versus placebo. In a post-hoc pooled analysis of 2.5 mg and 5 mg risedronate doses, also in patients at high risk of fracture, the relative risks of non-vertebral and hip fractures were significantly reduced by 20% (p = 0.03) and 30% (p = 0.02), respectively. In a Phase III study, the RRR of new vertebral fractures with 2.5 mg daily ibandronate was 62% (p = 0.0001) versus placebo after 3 years. Two pooled analyses of data from key randomised, double-blind, controlled trials with ibandronate dose levels consistent with 150 mg once-monthly reported significant RRRs in non-vertebral fractures of 38% (p = 0.038) and 30% (p = 0.041). In a bridging study, 150 mg once-monthly risedronate was non-inferior to 5 mg daily treatment for improvements in bone mineral density (BMD), but was significantly inferior for reductions in bone turnover markers (BTMs) (p < 0.05). Ibandronate 150 mg once monthly was superior to daily at 2 years in both surrogate marker measures, with significantly superior BMD gains reported at all sites (p < 0.05). In an extension of the bridging study, lumbar spine BMD progressively improved and previously reported femoral neck BMD gains were maintained with monthly ibandronate. Serum sCTX remained reduced within the premenopausal range.

CONCLUSIONS

Risedronate 150 mg once monthly has demonstrated less reduction of BTM and non-inferior BMD gains versus daily, whereas 150 mg once monthly ibandronate has demonstrated BTM suppression within the premenopausal range and BMD gains superior to the daily regimen. Furthermore, ibandronate has demonstrated antifracture efficacy with intermittent dosing in two pooled analyses. Risedronate has yet to demonstrate anti-fracture efficacy with an extended (intermittent) dosing regimen.

Lasofoxifene for the prevention and treatment of postmenopausal osteoporosis

Lasofoxifene is a selective estrogen receptor modulator (estrogen agonist/antagonist) that has completed phase III trials to evaluate safety and efficacy for the prevention and treatment of osteoporosis and for the treatment of vaginal atrophy in postmenopausal women. In postmenopausal women with low or normal bone mineral density (BMD), lasofoxifene increased BMD at the lumbar spine and hip and reduced bone turnover markers compared with placebo. In women with postmenopausal osteoporosis, lasofoxifene increased BMD, reduced bone turnover markers, reduced the risk of vertebral and nonvertebral fractures, and decreased the risk of estrogen receptor-positive breast cancer. In postmenopausal women with low bone mass, lasofoxifene improved the signs and symptoms of vulvovaginal atrophy. Clinical trials show that lasofoxifene is generally well tolerated with mild to moderate adverse events that commonly resolve even with drug continuation. Lasofoxifene has been associated with an increase in the incidence of venous thromboembolic events, hot flushes, muscle spasm, and vaginal bleeding. It is approved for the treatment of postmenopausal women at increased risk for fracture in some countries and is in the regulatory review process in others.

Assessing fracture risk and effects of osteoporosis drugs: bone mineral density and beyond

Although there have been numerous advances in the assessment of bone strength and fracture risk, the majority of these techniques can only be performed in research laboratories, making them largely unavailable to practicing clinicians. Prospective epidemiologic studies have identified risk factors that can be assessed within the clinic and combined with bone mineral density to allow clinicians to better identify untreated individuals at heightened risk for fracture and to make informed treatment decisions based on 10-year absolute fracture risk. This article discusses the assessment of fracture risk in clinical practice, reviews currently and soon-available bone measurement tools, and details the impacts of osteoporosis therapies on fracture risk.

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.

Progress in osteoporosis and fracture prevention: focus on postmenopausal women

In the past decade, we have witnessed a revolution in osteoporosis diagnosis and therapeutics. This includes enhanced understanding of basic bone biology, recognizing the severe consequences of fractures in terms of morbidity and short-term re-fracture and mortality risk and case finding based on clinical risks, bone mineral density, new imaging approaches, and contributors to secondary osteoporosis. Medical interventions that reduce fracture risk include sufficient calcium and vitamin D together with a wide spectrum of drug therapies (with antiresorptive, anabolic, or mixed effects). Emerging therapeutic options that target molecules of bone metabolism indicate that the next decade should offer even greater promise for further improving our diagnostic and treatment approaches.

New therapies for osteoporosis: zoledronic acid, bazedoxifene, and denosumab

Intravenous (IV) zoledronic acid, a new once-yearly bisphosphonate therapy, is approved by the US Food and Drug Administration for treatment of postmenopausal osteoporosis, glucocorticoid-induced osteoporosis, and osteoporosis in men. IV zoledronic acid significantly reduced the risk of vertebral, nonvertebral, and hip fractures in postmenopausal women and decreased risk of clinical fracture and clinical vertebral fracture in men and women with hip fracture. Two promising new therapies are in late clinical development. Denosumab is a monoclonal receptor activator of nuclear factor- kappaB ligand (RANKL) antibody given by subcutaneous injection every 6 months that has been shown to significantly reduce risk of vertebral-, nonvertebral-, and hip fracture in postmenopausal women. Bazedoxifene, an estrogen agonist/antagonist, has significantly reduced the risk of vertebral fracture in postmenopausal women; a post hoc analysis showed reduction in risk of nonvertebral fracture in high-risk women.

Pharmacology and clinical applications of selective estrogen receptor modulators

Compounds that can be described as selective estrogen receptor modulators (SERMs) have expanded dramatically over the past two decades. The ability of SERMs to act as estrogens in certain tissues while remaining inert or acting as an anti-estrogen in other tissues has opened up opportunities for treating specific estrogen-modulated diseases without accepting the risk of systemic estrogen activity. SERM development has resulted in significant therapeutic advances for breast cancer, osteoporosis and potentially other diseases associated with the menopause. After the publication of the Women's Health Initiative, interest in compound selectivity that reduces menopausal symptoms while protecting bone, breast, uterus and the heart has increased. Future SERMs may also have a therapeutic profile that can be tailored to specific patient populations, including men. This review paper summarizes the characteristics of different SERMs from various pharmacological categories and the feasibility and scope of their use for a large range of disease/health conditions.

Bazedoxifene/conjugated estrogens and quality of life in postmenopausal women

OBJECTIVE

To assess the effects of bazedoxifene/conjugated estrogens (BZA/CE) on sleep parameters and health-related quality of life (HR-QOL).

METHODS

This was a 12-week, multicenter, double-blind, placebo-controlled phase 3 study. Postmenopausal women with an intact uterus and experiencing >or=7 moderate-to-severe hot flushes daily were randomized to BZA 20 mg/CE 0.45 mg, BZA 20 mg/CE 0.625 mg, or placebo. In these secondary efficacy analyses, the Medical Outcomes Study (MOS) sleep scale and Menopause-Specific Quality of Life (MENQOL) questionnaires and the Menopause Symptoms Treatment Satisfaction Questionnaire (MS-TSQ) evaluated measures of sleep, menopausal symptoms, and satisfaction with treatment, respectively.

RESULTS

A total of 318 subjects (mean age, 53.4 years) received >or=1 dose of study drug. At Week 12, BZA 20 mg/CE 0.45 and 0.625 mg showed significant improvements over placebo in the MOS sleep scale for time to fall asleep, sleep adequacy, sleep disturbance, and sleep problems indexes I and II (P<0.001). A reduction in hot flush frequency was significantly associated with improvement in sleep parameters (P<0.05) based on linear regression and responder analyses. Both BZA/CE doses showed significantly greater improvements over placebo in vasomotor function and total MENQOL score (P<0.001). Results of the MS-TSQ showed that subjects treated with BZA/CE versus placebo reported significantly greater overall satisfaction with treatment (P<0.05), as well as greater satisfaction with sleep quality, ability to control hot flushes during the day and night, effect on mood/emotions, and tolerability.

CONCLUSION

Symptomatic postmenopausal women treated with BZA/CE experienced significant improvements in sleep parameters and overall HR-QOL.

Designing the ideal selective estrogen receptor modulator--an achievable goal?

Selective estrogen receptor modulators (SERMs), which lack the estrogen steroid moiety yet retain the ability to bind the estrogen receptor (ER), are known to confer mixed ER agonist or antagonist effects depending on the target tissue. The tissue-selective effects of SERMs have led to considerations in the clinical profile of an ideal SERM, which would have ER agonist activity in tissues where mimicking the action of estrogens is desirable, and ER neutral or antagonist activity in tissues estrogens have been shown to adversely stimulate. A number of newer SERMs, including bazedoxifene, lasofoxifene, ospemifene, and arzoxifene, are currently in clinical development for the prevention and treatment of postmenopausal osteoporosis and for other indications. Although the possibility of developing a single agent that has all of the desired characteristics of an ideal SERM seems to be unlikely, progress in the clinical development of SERMs targeted to the ER suggests that these newer compounds may have attributes that represent an improvement relative to existing SERMs. Further clinical investigation will help to clarify the relative benefits and risks of novel SERMs in development within specific indications.

Efficacy of tissue-selective estrogen complex of bazedoxifene/conjugated estrogens for osteoporosis prevention in at-risk postmenopausal women

OBJECTIVE

To evaluate the efficacy of the tissue-selective estrogen complex, bazedoxifene/conjugated estrogens (BZA/CE), for postmenopausal osteoporosis prevention.

DESIGN

Multicenter, randomized, double-blind, placebo- and active-controlled, phase 3 trial (Selective estrogen Menopause And Response to Therapy [SMART]-1).

SETTING

Outpatient clinical study.

PATIENT(S)

Women (n = 3,397) more than 5 years and 1-5 years postmenopause were enrolled in the Osteoporosis Prevention I and II Substudies, respectively.

INTERVENTION(S)

Single tablets of BZA (10, 20, or 40 mg) each with CE (0.625 or 0.45 mg), raloxifene (60 mg), or a placebo taken daily for 2 years.

MAIN OUTCOME MEASURE(S)

The primary outcome for both substudies was change in bone mineral density of the lumbar spine; bone mineral density was also measured at the hip.

RESULT(S)

In both substudies, bone mineral density increased significantly more with all BZA/CE doses compared with placebo at the lumbar spine and total hip, and for most BZA/CE doses compared with raloxifene at the lumbar spine. Osteocalcin and N-telopeptide significantly decreased with all BZA/CE doses vs. placebo and most BZA/CE doses vs. raloxifene.

CONCLUSION(S)

BZA/CE combinations decreased bone turnover and bone loss in postmenopausal women at increased risk for osteoporosis.

Evaluation of bazedoxifene/conjugated estrogens for the treatment of menopausal symptoms and effects on metabolic parameters and overall safety profile

OBJECTIVE

To evaluate the effects of a tissue-selective estrogen complex (TSEC) composed of bazedoxifene/conjugated estrogens (BZA/CE) on menopausal symptoms, metabolic parameters, and overall safety.

DESIGN

Multicenter, double-blind, placebo- and active-controlled phase 3 trial (Selective estrogens, Menopause, And Response to Therapy [SMART]-1).

SETTING

Outpatient clinical.

PATIENT(S)

Healthy, postmenopausal women (n = 3,397) age 40 to 75 with an intact uterus.

INTERVENTION(S)

Single tablets of BZA (10, 20, or 40 mg), each with CE (0.625 or 0.45 mg); raloxifene 60 mg; or placebo taken daily for 2 years.

MAIN OUTCOME MEASURE(S)

Hot flushes, breast pain, vaginal atrophy, metabolic parameters, and adverse events.

RESULT(S)

BZA (20 mg)/CE (0.625 or 0.45 mg) significantly reduced the frequency and severity of hot flushes and improved measures of vaginal atrophy compared with placebo. At week 12, the daily number of hot flushes decreased by 51.7% to 85.7% with all BZA/CE doses vs. 17.1% for placebo. BZA/CE improved lipid parameters and homocysteine levels, did not significantly change carbohydrate metabolism, and had only minor effects on some coagulation parameters. The incidences of breast pain and adverse events were similar between BZA/CE and placebo.

CONCLUSION

The TSEC composed of BZA (20 mg)/CE (0.625 or 0.45 mg) is an effective and safe treatment for menopausal symptoms.

Bazedoxifene reduces vertebral and clinical fractures in postmenopausal women at high risk assessed with FRAX

INTRODUCTION

Bazedoxifene has been shown to significantly decrease the risk of vertebral fractures in postmenopausal women. No significant effect was noted on the risk of clinical fractures, but fracture risk reduction was reported in a post hoc subgroup analysis in a high risk group categorised on the basis of BMD and prior fracture.

AIMS

The aim of this study was to re-evaluate the efficacy of bazedoxifene on fracture outcomes avoiding subgroup analysis by examining the efficacy of intervention as a function of fracture risk.

METHODS

The phase III study was a double-blind, randomised, placebo- and raloxifene-controlled randomised 3-year multinational study that enrolled 7492 osteoporotic women aged 55 years or more (mean age=66 years). For the present analysis, women taking raloxifene were excluded (n=1849), and we compared the effects of two doses of bazedoxifene (20 and 40 mg daily combined) with placebo on the risk of all clinical fractures as well as the risk of morphometric vertebral fracture. The risk of a major osteoporotic fracture was assessed using region specific FRAX algorithms, and the relationship between pre hoc 10-year fracture probabilities and efficacy examined by Poisson regression.

RESULTS

Overall, bazedoxifene was associated with a significant 39% decrease in incident morphometric vertebral fractures (hazard ratio HR=0.61; 95% CI=0.43-0.86; p=0.005) and a non-statistically significant 16% decrease in all clinical fractures (hazard ratio HR=0.84; 95% CI=0.67-1.06; p=0.14) compared to placebo. Hazard ratios for the effect of bazedoxifene on all clinical fractures decreased with increasing fracture probability. In patients with 10-year fracture probabilities at or above 16%, bazedoxifene was associated with a significant decrease in the risk of all clinical fractures. The 16% probability threshold corresponded to the 80th percentile of the study population. Hazard ratios for the effect of bazedoxifene on morphometric vertebral fractures also decreased with increasing fracture probability. In patients with 10-year fracture probabilities above 6.9% (corresponding to the 41st percentile), bazedoxifene was associated with a significant decrease in the risk of morphometric vertebral fractures. At equivalent fracture probability percentiles, the treatment effect of bazedoxifene was greater on vertebral fracture risk than on the risk of all clinical fractures. For example, at the 90th percentile of FRAX probability, bazedoxifene was associated with a relative risk reduction of 33% (95% CI=7-51%) for all clinical fractures and 51% reduction (95% CI=21-69%) for morphometric vertebral fractures. The findings were robust to several sensitivity analyses.

CONCLUSION

Bazedoxifene (20 and 40 mg doses combined) significantly decreased the risk of all clinical fractures and morphometric vertebral fractures in women at or above a FRAX based fracture probability threshold. These results, consistent with the previous subgroup analysis, suggest that bazedoxifene should be targeted preferentially to women at high fracture risk.

FRAX and its applications to clinical practice

The introduction of the WHO FRAX algorithms has facilitated the assessment of fracture risk on the basis of fracture probability. FRAX integrates the influence of several well validated risk factors for fracture with or without the use of BMD. Its use in fracture risk prediction poses challenges for patient assessment, the development of practice guidelines, the evaluation of drug efficacy and reimbursement, as well as for health economics which are the topics outlined in this review.

Teriparatide vertebral fracture risk reduction determined by quantitative and qualitative radiographic assessment

OBJECTIVE

Most registration studies for new osteoporosis drugs have used a combination of quantitative morphometry (QM) and visual semiquantitative reading (SQ) to define vertebral fractures. However, in the pivotal teriparatide Fracture Prevention Trial (ClinicalTrials.gov Identifier: NCT00670501), vertebral fractures were previously defined only by the SQ methodology. The objective of this study was to define the effect of teriparatide on the incidence of vertebral fractures defined by QM plus SQ assessment.

RESEARCH DESIGN AND METHODS

Radiographs from the Fracture Prevention Trial placebo- and teriparatide 20 microg/day groups were re-assessed in blinded fashion, defining incident vertebral fractures for vertebrae meeting all of the following requirements: (a) 20% decrease in height by QM, (b) a corresponding 4 mm decrease in height (c) an increase of at least one grade by visual SQ assessment by a radiologist.

RESULTS

By this methodology, vertebral fracture risk was reduced in the teriparatide versus placebo group by 84% (RR = 0.16, p < 0.001). The risk of two or more vertebral fractures was also significantly reduced by 94% (RR = 0.06, p < 0.001). The fractures in the teriparatide group were of lesser severity than the fractures in the placebo group. The absolute benefit of teriparatide was greatest in those patients with the highest number and severity of prevalent vertebral fractures.

CONCLUSIONS

As assessed by QM plus SQ, teriparatide reduced the incidence of vertebral fractures.

Bazedoxifene for the prevention of postmenopausal osteoporosis

Bazedoxifene acetate is a novel, chemically distinct selective estrogen receptor modulator (SERM) that has been specifically developed after a stringent preclinical screening in order to obtain favorable effects on the skeleton and lipid metabolism with the additional improvement of a neutral effect on hot flushes and without stimulating the uterus or the breast. In both preclinical and clinical studies this SERM was shown to maintain BMD, prevent fractures, and reduce total cholesterol. Moreover, bazedoxifene also showed an improved uterine profile and demonstrated estrogen antagonistic activity on the endometrium. Importantly, this latter capacity has led to the development of a novel class of menopausal therapy called tissue selective estrogen complex (TSEC), in which bazedoxifene is combined with conjugated estrogen. The rationale for selecting bazedoxifene as the SERM in this TSEC combination is that it may offset estrogen stimulation of endometrial and breast tissue, without the necessity of using a progestin in women with an intact uterus, without aggravating menopausal vasomotor symptoms, but with an additive effect on bone. Preliminary data from phase 3 clinical trials appear to confirm this hypothesis, showing a greater effect of bazedoxifene on BMD with respect to raloxifene, coupled with efficacy on menopausal vasomotor symptoms not achieved by SERM alone. These properties and the safety profile of this combination, if confirmed long-term in ongoing phase 3 trials, might significantly affect the way women and physicians approach menopause and its related disorders.