Selective estrogenic effects of a novel triphenylethylene compound, FC1271a, on bone, cholesterol level, and reproductive tissues in intact and ovariectomized rats

Estradiol and Estrogen-like Alternative Therapies in Use: The Importance of the Selective and Non-Classical Actions

Estrogen is one of the most important female sex hormones, and is indispensable for reproduction. However, its role is much wider. Among others, due to its neuroprotective effects, estrogen protects the brain against dementia and complications of traumatic injury. Previously, it was used mainly as a therapeutic option for influencing the menstrual cycle and treating menopausal symptoms. Unfortunately, hormone replacement therapy might be associated with detrimental side effects, such as increased risk of stroke and breast cancer, raising concerns about its safety. Thus, tissue-selective and non-classical estrogen analogues have become the focus of interest. Here, we review the current knowledge about estrogen effects in a broader sense, and the possibility of using selective estrogen-receptor modulators (SERMs), selective estrogen-receptor downregulators (SERDs), phytoestrogens, and activators of non-genomic estrogen-like signaling (ANGELS) molecules as treatment.

Pharmacotherapeutic options for the treatment of menopausal symptoms

Introduction: Menopausal symptoms can be very overwhelming for women. Over the years, many pharmacotherapeutic options have been tested, and others are still being developed. Hormone therapy (HT) is the most efficient therapy for managing vasomotor symptoms and related disturbances. The term HT comprises estrogens and progestogens, androgens, tibolone, the tissue-selective estrogen complex (TSEC), a combination of bazedoxifene and conjugated estrogens, and the selective estrogen receptor modulators, such as ospemifene. Estrogens and progestogens and androgens may differ significantly for chemical structure and can be delivered through different routes, thereby displaying various pharmacological and clinical properties. Tibolone, TSEC and SERM also exhibit unique pharmacodynamics that can be exploited to obtain distinctive therapeutic effects. Non-hormonal options fall mainly into the selective serotonin reuptake inhibitor (SSRI) and selective noradrenergic reuptake inhibitor (SNRI), GABA-analogue drug classes.Areas covered: Herein, the authors describe the pharmacokinetics and pharmacodynamics of hormonal (androgens, estrogens, progestogens, tibolone, TSEC, SERMs) and non-hormonal (SSRIs, SNRIs, Gabapentin, Pregabalin, Oxybutynin, Neurokinin antagonists) treatments for menopausal symptoms and report essential clinical trial data in humans.Expert opinion: Patient tailoring of treatment is key to managing symptoms of menopause. Physicians must have in-depth knowledge of the pharmacology of compounds to tailor therapy to the individual patient's characteristics and needs.

Ospemifene efficacy and safety data in women with vulvovaginal atrophy

Vulvovaginal atrophy (VVA) is a frequent, underreported and underdiagnosed condition. Ospemifene is a third-generation Selective Estrogen Receptor Modulator (SERM) that has been shown to be effective in women with VVA and dyspareunia, vaginal dryness and vulvar vestibular symptoms. Some of the possible side effects included by FDA and EMA are hot flushes, headache, muscle spasms, vaginal bleeding and vaginal discharge. Ospemifene does not increase the incidence of endometrial cancer or hyperplasia. While the efficacy is comparable with that of estrogenic treatments, ospemifene is not only well tolerated and safe but also reduces bone turnover in postmenopausal women, and available data indicate no safety concerns for breast tissue.

Ospemifene in the Management of Vulvar and Vaginal Atrophy: Focus on the Assessment of Patient Acceptability and Ease of Use

Endocrinological changes that occur with menopause lead to a chronic and progressive condition named vulvar and vaginal atrophy (VVA). This disease is characterized by symptoms such as dryness, dyspareunia, itching, burning, and dysuria. According to recent epidemiological studies, VVA has a high prevalence and can also occur in younger women prior to the menopause, negatively affecting quality of life, sexual function, intimacy and relationship with the partner. Accordingly, therapy should be effective, initiated early and continued for as long as possible. Up to recent years, available therapeutic options have included over-the-counter lubricants and moisturizers, vaginal oestrogens and systemic hormones. These products are not indicated for all women. Hormones are mostly contraindicated in women with a history of hormone-sensitive cancer and are frequently not accepted even by women without contraindications. Local therapies are frequently considered uncomfortable, difficult to apply, and messy. Indeed, these treatments have a high spontaneous discontinuation rate, mostly due to dissatisfaction, safety concern, side effects and difficulty in vaginal placement. Recently, ospemifene, a new non-hormonal systemic remedy, was approved by FDA (Food and Drug Administration) and EMA (European Medicines Agency) for the treatment of the two most bothersome symptoms of VVA: dryness and dyspareunia. Because ospemifene is a selective estrogen receptor modulator (SERM), it can be administered also in women with a history of breast cancer, and this makes it more acceptable by any woman. In addition, its route of administration minimizes those bothersome side effects intrinsic to the vaginal route of administration. Available data indicate that women using ospemifene have higher adherence to treatment, higher persistence and lower discontinuation rate. Satisfaction is higher than with other local therapies and overall health care cost is lower.

Tissue selective estrogen complex (TSEC): a review

Objective:

This review describes historical development of selective estrogen receptor modulators (SERMs) and their combination with estrogens, termed a tissue selective estrogen complex (TSEC), and considers the potential for future TSEC development.

Methods:

This narrative review is based on literature identified on PubMed and the TSEC research and development experience of the authors.

Results:

SERMs have estrogenic and antiestrogenic effects in various tissues; however, no single agent has achieved an optimal balance of agonist and antagonist effects for the treatment of menopausal symptoms. Clinically, a number of SERMs protect against osteoporosis and breast cancer but can exacerbate vasomotor symptoms. Estrogens alleviate menopausal hot flushes and genitourinary symptoms as well as reduce bone loss, but the addition of a progestogen to menopausal hormone therapy to protect against endometrial cancer increases vaginal bleeding risk, breast tenderness, and potentially breast cancer. The search for an effective menopausal therapy with better tolerability led to the investigation of TSECs. Clinical development of a TSEC consisting of conjugated estrogens/bazedoxifene increased understanding of the importance of a careful consideration of the combination's components and their respective doses to balance safety and efficacy. Bazedoxifene is an estrogen receptor agonist in bone but an antagonist/degrader in the endometrium, which has contributed to its success as a TSEC component. Other oral TSEC combinations studied thus far have not demonstrated similar endometrial safety.

Conclusions:

Choice of SERM, selection of doses, and clinical trial data evaluating safety and efficacy are key to ensuring safety and adequate therapeutic effect of TSECs for addressing menopausal symptoms.

Ospemifene for the treatment of menopausal vaginal dryness, a symptom of the genitourinary syndrome of menopause

Introduction: Vulvovaginal atrophy (VVA), a component of the genitourinary syndrome of menopause, is a progressive condition due to decline in estrogen leading to vaginal and vulvar epithelial changes. Accompanying symptoms of dryness, irritation, burning, dysuria, and/or dyspareunia have a negative impact on quality of life. Ospemifene is a selective estrogen receptor modulator (SERM) approved by the FDA for moderate to severe dyspareunia and vaginal dryness due to postmenopausal VVA. Areas covered: PubMed was searched from inception to March 2019 with keywords ospemifene and vulvar vaginal atrophy to review preclinical and clinical data describing the safety and efficacy of ospemifene for vaginal dryness and dyspareunia due to VVA. Covered topics include efficacy of ospemifene on vaginal cell populations, vaginal pH, and most bothersome VVA symptoms; imaging studies of vulvar and vaginal tissues; effects on sexual function; and safety of ospemifene on endometrium, cardiovascular system, and breast. Expert opinion: Ospemifene is significantly more effective than placebo in all efficacy analyses studied, working through estrogen receptors and possibly androgen receptors. Safety as assessed by adverse events was generally comparable to that with placebo and to other SERMs, and/or adverse events were not clinically meaningful. No cases of endometrial or breast cancer were reported.

Effects of ospemifene on bone in postmenopausal women

Ospemifene is a selective estrogen-receptor modulator approved for treating menopause-related moderate to severe dyspareunia and vaginal dryness, symptoms of vulvovaginal atrophy (VVA), in the United States, and for treating menopause-related, symptomatic VVA in women not appropriate for local estrogen therapy in Europe. This review summarizes the effects of ospemifene on bone, including bone biomarker data from a phase 3 vaginal dryness study. Early-phase studies of postmenopausal women showed that ospemifene dose-dependently decreased bone turnover markers versus placebo, similar to raloxifene. A 12-week, phase 3 study of ospemifene 60 mg/day in postmenopausal women showed improvements in all VVA parameters and significantly greater decreases in seven of nine bone biomarkers versus placebo. Lower bone resorption markers with ospemifene were observed regardless of time since menopause (≤5 years or >5 years) or baseline bone mineral density (BMD) (normal [n = 18], osteopenia [n = 164], or osteoporosis [n = 21]). Biomarker studies (n = 565 who took ospemifene) therefore support a potential role for ospemifene in maintaining bone health (and possibly reducing fracture risk) in postmenopausal women taking it for VVA; however, caution is warranted because data are limited to biochemical markers, rather than fracture and BMD. Although studies show that bone turnover predicts BMD and fractures, any hypothesis about a bone-sparing effect of ospemifene needs testing in rigorous, long-term, phase 3 studies monitoring fractures and BMD.

SERMs Promote Anti-Inflammatory Signaling and Phenotype of CD14+ Cells

Signaling via estrogen receptors (ER) is recognized as an essential part of the immune regulation, and ER-mediated signaling is involved in autoimmune reactions. Especially ERα activation in immune cells has been suggested to skew cytokine production toward Th2/M2-type mediators, which can have protective effect on inflammatory diseases and reduce Th1 and Th17 responses. These effects are caused by increased alternative activation of macrophages and changes in the activation of different T cell populations. In humans, hormonal status has been shown to have a major impact on several inflammatory diseases. Selective estrogen receptor modulators (SERMs) are ER ligands that regulate ER actions in a tissue-specific manner mostly lacking the adverse effects of steroid hormones. The impact of SERMs on the immune system is less studied, but it is suggested that certain SERMs may also produce immunoprotective effects. Here, we show that two novel SERMs and raloxifene affect immune cells by promoting M2 macrophage phenotype, alleviating NFκB activity, inhibiting T cell proliferation, and stimulating the production of anti-inflammatory compounds such as IL10 and IL1 receptor antagonist. Thus, these compounds have high potency as drug candidates against autoimmune diseases.

Ospemifene's effects on lipids and coagulation factors: a post hoc analysis of phase 2 and 3 clinical trial data

Objective:

To evaluate the effect of ospemifene 60 mg on the lipid and coagulation parameters of postmenopausal women using data from five phase 2 and 3 clinical trials.

Methods:

Data for lipids and coagulation factors for 2,166 postmenopausal women were pooled from five randomized, placebo-controlled studies. Lipid and coagulation parameters included in this analysis were total cholesterol, high-density lipoproteins (HDL), low-density lipoproteins (LDL), triglycerides, activated partial thromboplastin time (aPTT), fibrinogen, antithrombin antigen, protein C Ag, and protein S Ag free.

Results:

Mean percent changes in HDL and LDL were significantly greater with ospemifene versus placebo at month 3 (HDL: 4.4% vs 0.2%; LDL: −5.2% vs 2.4%), month 6 (HDL: 5.1% vs 1.5%; LDL: −6.7% vs 2.4%), and month 12 (HDL: 2.3% vs −1.9%; LDL: −7.0% vs −2.1%; P < 0.05, for all comparisons). Ospemifene significantly reduced total cholesterol at 6 months (−1.8% vs 1.6%; P = 0.0345 versus placebo), and changes in triglycerides with ospemifene were similar to placebo at all three time points. In subgroup analyses based on age, body mass index, and baseline triglyceride level, ospemifene increased HDL and decreased LDL, but had no significant effect on total cholesterol and triglycerides relative to placebo. Ospemifene significantly improved fibrinogen and protein C antigen levels relative to placebo at months 3 (−8.7% vs −0.8% and −2.7% vs 0.5%, respectively), 6 (−6.0% vs 6.7% and −3.6 vs 8.0%), and 12 (−8.7% vs 7.3% and −4.5% vs 6.6%; P < 0.01, for all). The levels of all coagulation factors remained within the normal range throughout the studies.

Conclusion:

Ospemifene 60 mg does not have a detrimental effect on lipid and coagulation parameters of postmenopausal women with up to 12 months of use.

Ospemifene: A Novel Option for the Treatment of Vulvovaginal Atrophy

Ospemifene—a third-generation selective estrogen receptor modulator approved by the Food and Drug Administration in 2013—is an oral medication for the treatment of dyspareunia. In postmenopausal women with vulvovaginal atrophy, ospemifene significantly improves the structure and pH levels of the vagina, reducing dyspareunia. It is available as a 60-mg tablet; hence, women who may have had prior difficulty with vaginal administration or on-demand use of nonprescription lubricants and moisturizers would likely prefer this form of treatment. Preclinical studies demonstrated that ospemifene has an estrogen agonist action on the bone, reducing the cell proliferation of ductal carcinoma in an in situ model. Studies evaluating the safety of treatment for up to 52 weeks have shown that ospemifene is a safe medication with minimal impact on the endometrium. Further studies with larger number of subjects are necessary to better conclude its effects and long-term safety.

Clinical update on the use of ospemifene in the treatment of severe symptomatic vulvar and vaginal atrophy

The physiological decrease in vaginal estrogens is accountable for the emergence of vulvar and vaginal atrophy (VVA) and its related symptoms such as vaginal dryness, dyspareunia, vaginal and/or vulvar irritation or itching, and dysuria. The repercussion of these symptoms on quality of life often makes it necessary to initiate treatment. Up until now, the treatments available included vaginal moisturizers and lubricants, local estrogens, and hormonal therapy. However, therapeutic options have now been increased with the approval of 60 mg ospemifene, the first nonhormonal oral treatment with an agonist effect on the vaginal epithelium and an endometrial and breast safety profile which makes it unique. This is the first selective estrogen receptor modulator indicated in women with moderate-to-severe vaginal atrophy not eligible for local estrogen treatment. Considering that "local estrogen noneligible women" are those in whom such treatment cannot be administered either because it is contraindicated or due to skill issues, who are averse to the mode and convenience of vaginal products' administration or to their use on account of potential systemic absorption, or those who demonstrate dissatisfaction in terms of efficacy and safety, it is clear that there is a significant unmet medical need in VVA management. In fact, a great number of women show lack of adherence, dropping out of at least one VVA treatment, including nonhormonal moisturizers and lubricants, which they consider to be ineffective and uncomfortable. If they could choose, many of them may opt for oral treatment. In Phase III studies, ospemifene demonstrated efficacy in vaginal dryness and dyspareunia, regenerating vaginal cells, improving lubrication, and reducing pain during sexual intercourse. Symptoms improved in the first 4 weeks and endured for up to 1 year. Additionally, it demonstrated a good endometrial, cardiovascular system, and breast safety profile.

Effects of ospemifene on the female reproductive and urinary tracts: translation from preclinical models into clinical evidence

Objective

Treatment of menopausal symptoms by compounds with tissue-selective estrogen agonist/antagonist effects, often called selective estrogen receptor modulators, has been researched as an alternative to the use of estrogen therapy. These structurally diverse molecules elicit tissue-dependent responses in hormone-responsive tissues and organs, exhibiting variations in estrogenic activity in preclinical models of postmenopausal reproductive tissues that may improve postmenopausal women’s health (eg, prevention and treatment of breast cancer, osteoporosis, and vulvar and vaginal atrophy).

Methods

This literature review investigates whether preclinical data predicted the clinical effects of ospemifene on female reproductive and urinary tract tissues and compares these findings with the specific vaginal effects of other estrogen receptor agonists/antagonists (tamoxifen, raloxifene, and bazedoxifene) in preclinical and clinical studies. Lasofoxifene, although not currently available, is included because of its unique effects on vaginal tissue.

Results

The response of endometrial and vaginal tissues to estrogen receptor agonists/antagonists can be differentiated using transvaginal ultrasound, endometrial histopathology, cytologic examination of vaginal smears, assessment of physical changes in the vagina, and relief of symptoms associated with vulvar and vaginal atrophy (such as dyspareunia).

Conclusions

Available evidence indicates that ospemifene has unique effects on tissue, leading to a favorable long-term profile for the relief of vulvar and vaginal atrophy compared with other estrogen receptor agonists/antagonists (eg, tamoxifen, raloxifene, and bazedoxifene) with no short-term concerns about endometrial safety (based on endometrial hyperplasia, carcinoma, endometrial spotting, and endometrial bleeding).

Selective estrogen receptor modulators and the combination therapy conjugated estrogens/bazedoxifene: A review of effects on the breast

Traditional menopausal hormone therapy containing estrogens/progestin has been associated with an increased risk of breast cancer, and estrogen exposure is known to promote growth and proliferation of a majority of breast cancers. Therefore, it is important for clinicians to consider the breast safety profile of any hormone-based therapy used in postmenopausal women. This review provides an overview of the breast safety and tolerability profiles of currently marketed selective estrogen receptor modulators, antiestrogens, and the first tissue selective estrogen complex combining conjugated estrogens with the selective estrogen receptor modulator bazedoxifene in postmenopausal women. Selective estrogen receptor modulators and antiestrogens act as estrogen receptor antagonists in the breast. Tamoxifen, toremifene, and the selective estrogen receptor degrader fulvestrant are used to treat breast cancer, and tamoxifen and raloxifene protect against breast cancer in high-risk women. Postmenopausal women using selective estrogen receptor modulators for prevention or treatment of osteoporosis (raloxifene, bazedoxifene) can be reassured that these hormonal treatments do not adversely affect their risk of breast cancer and may, in the case of raloxifene, even be protective. There are limited data on breast cancer in women who use ospemifene for dyspareunia. Conjugated estrogens/bazedoxifene use for up to two years did not increase mammographic breast density or breast pain/tenderness, and there was no evidence of an increased risk of breast cancer, suggesting that conjugated estrogens/bazedoxifene has an improved breast safety profile compared with traditional menopausal hormone therapies. Future research will continue to focus on development of selective estrogen receptor modulators and selective estrogen receptor modulator combinations capable of achieving the ideal balance of estrogen receptor agonist and antagonist effects.

Endometrial safety of ospemifene: results of the phase 2/3 clinical development program

OBJECTIVE

This study aims to assess the endometrial safety of ospemifene based on phase 2/3 clinical trials of postmenopausal women with up to 52 weeks of exposure to ospemifene 60 mg/day versus placebo.

METHODS

Endometrial safety was evaluated in a development program of six randomized, double-blind, placebo-controlled, parallel-group studies of postmenopausal women aged between 40 and 80 years who had vulvar and vaginal atrophy. Participants were randomized 1:1 to ospemifene 60 mg/day or placebo in one 6-week trial and three 12-week trials; one of the 12-week trials had a 40-week extension study. In a separate 52-week trial, women were randomized 6:1 to ospemifene 60 mg/day or placebo. Endometrial safety was assessed by endometrial histology (biopsy), transvaginal ultrasound, and gynecologic examination.

RESULTS

In these trials, 1,242 women who received ospemifene 60 mg/day and 924 women who received placebo were evaluable for safety. Endometrial hyperplasia occurred in less than 1% of women treated with ospemifene; no endometrial cancer was reported. The mean (SD) increase in endometrial thickness among women treated with ospemifene was 0.51 (1.54) mm at 12 weeks, 0.56 (1.61) mm at 6 months, and 0.81 (1.54) mm at 12 months. Women who received placebo had a mean (SD) increase of 0.07 (1.23) mm at 12 months.

CONCLUSIONS

These clinical trial data indicate that up to 52 weeks of treatment with oral ospemifene 60 mg/day was safe for the endometrium. There was no increase in the incidence of endometrial cancer or hyperplasia among postmenopausal women treated with ospemifene compared with placebo.

Genitourinary Syndrome of Menopause in Breast Cancer Survivors: Are We Facing New and Safe Hopes?

Breast cancer survivors (BCSs) often suffer from menopausal symptoms induced by systemic treatments, with a consequent negative effect on quality of life. Since the introduction of aromatase inhibitors as the standard therapy for hormone-dependent tumors, genitourinary syndrome of menopause (GSM) has become a main problem for BCSs. This new terminology refers to the wide range of vaginal and urinary symptoms related to menopause, which can be relieved by estrogen therapy. Unfortunately, systemic hormone therapy is contraindicated for BCSs and also vaginal estrogens at standard dosage might influence the risk of recurrence because they cause a significant increase of circulating estrogens. Nonhormonal vaginal moisturizers or lubricants are the first choice for BCSs but only have limited and short-term efficacy. New strategies of management of GSM are now available, including: (1) low-dose or ultra low-dose vaginal estrogens; (2) oral selective estrogen receptor modulators (ospemifene); (3) androgen therapy; (4) physical treatment with vaginal laser; and (5) psychosocial interventions. In this review we discuss and analyze these different options.

Safety and efficacy of ospemifene for the treatment of dyspareunia associated with vulvar and vaginal atrophy due to menopause

During the menopausal transition, women experience a number of symptoms due to declining estrogen levels, including vasomotor symptoms and vulvar and vaginal atrophy (VVA). Unlike vasomotor symptoms, vaginal dryness and dyspareunia, the main symptoms of VVA, typically worsen without treatment and can significantly impact the quality of life. Up to 60% of postmenopausal women may be affected by VVA, but many women unfortunately do not seek treatment due to embarrassment or other factors. After 20+ years in development, ospemifene (Osphena™) was approved by the US Food and Drug Administration in 2013 for treatment of moderate-to-severe dyspareunia associated with VVA due to menopause. As the first non-hormonal alternative to estrogen-based products for this indication, the approval of ospemifene represents a significant milestone in postmenopausal women’s health. Ospemifene is a non-steroidal estrogen receptor agonist/antagonist, also known as a selective estrogen receptor modulator (SERM), from the same chemical class as the breast cancer drugs tamoxifen and toremifene. Unlike other selective estrogen receptor modulators, ospemifene exerts a strong, nearly full estrogen agonist effect in the vaginal epithelium, making it well suited for the treatment of dyspareunia in postmenopausal women. Results of Phase III clinical trials showed that ospemifene significantly improved the vaginal maturation index (decreased parabasal cells and increased superficial cells), decreased vaginal pH, and decreased severity of the self-identified most bothersome symptom (dyspareunia or vaginal dryness) compared to placebo. Long-term safety studies revealed that 60 mg ospemifene given daily for 52 weeks was well tolerated and was not associated with any endometrium or breast-related safety concerns. This review discusses the preclinical and clinical data supporting the use of ospemifene for the treatment of dyspareunia associated with VVA due to menopause and provides an overview of its clinical safety.

Clinical effects of selective estrogen receptor modulators on vulvar and vaginal atrophy

OBJECTIVE

Vaginal estrogen therapy at the lowest effective dose is generally recommended for the treatment of vulvar and vaginal atrophy (VVA), but not all women are candidates. Selective estrogen receptor modulators (SERMs) aim to elicit specific positive effects on targeted tissues with neutral or minimal negative effects on other tissues. This review compares the vaginal effects of currently available and investigational SERMs.

METHODS

Relevant English-language articles published between 1980 and 2012 were identified through the PubMed database (search string "[Selective Estrogen Receptor Modulator OR SERM] AND [Vulvar OR Vaginal] AND Atrophy"), article reference lists, and EMBASE searches for individual SERMs. Both authors reviewed all articles, which formed the basis of this narrative literature review.

RESULTS

Activity profiles of SERMs in various tissues are distinct. Tamoxifen and arzoxifene have no specific positive vaginal effects but have reported variable or adverse gynecologic effects. Raloxifene does not improve VVA but can be used safely in combination with vaginal estrogen. Bazedoxifene has no demonstrated efficacy for VVA but, in combination with oral conjugated equine estrogens, improves the signs and symptoms of VVA. SERMs with positive vaginal effects (such as improvement in the vaginal maturation index, reduced vaginal pH, and improvement in the signs and symptoms of VVA) on postmenopausal symptomatic women include lasofoxifene (clinical development on hold) and ospemifene, which was recently approved for the treatment of VVA-related dyspareunia, with a class effect warning of potential venous thrombosis risk.

CONCLUSIONS

SERMs that specifically target the pathophysiology underlying VVA may provide an alternative to vaginal or systemic estrogen therapy.

From empirical to mechanism-based discovery of clinically useful Selective Estrogen Receptor Modulators (SERMs)

Our understanding of the molecular mechanisms underlying the pharmacological actions of estrogen receptor (ER) ligands has evolved considerably in recent years. Much of this knowledge has come from a detailed dissection of the mechanism(s) of action of the Selective Estrogen Receptor Modulators (SERMs) tamoxifen and raloxifene, drugs whose estrogen receptor (ER) agonist/antagonist properties are influenced by the cell context in which they operate. These studies have revealed that notwithstanding differences in drug pharmacokinetics, the activity of an ER ligand is determined primarily by (a) the impact that a given ligand has on the receptor conformation and (b) the ability of structurally distinct ER-ligand complexes to interact with functionally distinct coregulators. Exploitation of the established relationships between ER structure and activity has led to the development of improved SERMs with more favorable therapeutic properties and of tissue-selective estrogen complexes, drugs in which a SERM and an ER agonist are combined to yield a blended activity that results in distinct clinical profiles. Remarkably, endogenous ligands that exhibit SERM activity have also been identified. One of these ligands, 27-hydroxycholesterol (27HC), has been shown to manifest ER-dependent pathological activities in the cardiovascular system, bone and mammary gland. Whereas the physiological activity of 27HC remains to be determined, its discovery highlights how cells have adopted mechanisms to allow the same receptor ligand complex to manifest different activities in different cells, and also how these processes can be exploited for new drug development.

Ospemifene: a first-in-class, non-hormonal selective estrogen receptor modulator approved for the treatment of dyspareunia associated with vulvar and vaginal atrophy

Ospemifene is a selective estrogen receptor modulator (SERM) approved for the treatment of dyspareunia associated with vulvar and vaginal atrophy (VVA) due to menopause. As the first non-hormonal treatment for this indication, the approval of ospemifene represents a significant milestone in postmenopausal women's health. Ospemifene is a triphenylethylene similar in chemical structure to tamoxifen and toremifene. Consistent with other SERMs such as tamoxifen, toremifene, and raloxifene, ospemifene possesses a distinctive mix of estrogenic and antiestrogenic tissue-specific effects in bone, breast tissue, serum lipids, and the vagina. Among the approved SERMs, ospemifene is the only agent with a nearly full estrogen agonist effect on the vaginal epithelium while having neutral to slight estrogenic effects in the endometrium, making ospemifene uniquely suited for the treatment of dyspareunia associated with VVA, also known as atrophic vaginitis, which affects up to 50% of postmenopausal women. This review begins with a brief history of the discovery of ospemifene, its mechanism of action, and its preclinical development, with an emphasis on its tissue-specific effects on bone, breast, uterus and endometrium, serum lipids and vagina. A brief discussion on the genotoxicity of ospemifene compared to tamoxifen and toremifene is included. The focus then shifts to the clinical development of ospemifene from Phase I through Phase III. We will close with the FDA approval of ospemifene and a justification of the future clinical evaluation of ospemifene as a potential breast cancer chemopreventive agent, where several preclinical studies in different rodent breast cancer models strongly suggest ospemifene is as effective as tamoxifen.

Ospemifene: a novel selective estrogen receptor modulator for treatment of dyspareunia

Ospemifene is a novel, oral selective estrogen receptor modulator that has been approved in the USA for treatment of dyspareunia. The decline in estrogen during menopause creates vulvovaginal changes that can cause symptoms that adversely impact women psychosexually. Many women are reluctant to discuss painful sex and providers must proactively inquire about sexuality issues. Ospemifene has been shown to reverse changes associated with vulvovaginal atrophy and relieve symptoms of dyspareunia. Safety studies of treatment up to 52 weeks have shown ospemifene to be safe with no impact on endometrial hyperplasia/carcinoma, venous thrombotic events or pelvic organ prolapse. Further studies are needed to evaluate its role in bone and breast health.

An overview of current and emerging SERMs

Selective estrogen receptor modulators (SERMs) are compounds that exhibit tissue-specific estrogen receptor (ER) agonist or antagonist activity, and are used for various indications, including treatment of breast cancer, osteoporosis, and menopausal symptoms. Endometrial safety has been a key differentiator between SERMs in clinical practice. For example, tamoxifen exhibits ER agonist activity in the uterus, resulting in an increased risk of endometrial hyperplasia and malignancy, whereas raloxifene and bazedoxifene have neutral effects on the uterus. Based on their efficacy and long-term safety, SERMs are increasingly being prescribed for women who cannot tolerate other treatment options and for younger women at an increased risk of fracture who may remain on therapy for long periods of time. Continuing advances in the understanding of SERM mechanisms of action and structural interactions with the ER may lead to the development of new agents and combinations of agents to provide optimal treatments to meet the varying needs of postmenopausal women. One such example is the tissue selective estrogen complex, which partners a SERM with 1 or more estrogens, with the aim of blending the desired estrogen-receptor agonist activities of estrogens on vasomotor symptoms, vulvar-vaginal atrophy, and loss of bone mass with the tissue selectivity of a SERM.

Ospemifene for the treatment of vulvovaginal atrophy and dyspareunia in postmenopausal women

Vulvovaginal atrophy (VVA) and dyspareunia are common problems experienced by postmenopausal women, although few seek treatment. Symptom-based therapies include nonhormonal vaginal lubricants, vaginal moisturizers, low-dose vaginal estrogen, and systemic estrogen. The 2013 United States Food and Drug Administration approval of ospemifene, an estrogen agonist/antagonist for the treatment of moderate-to-severe dyspareunia associated with VVA, increased options available to women. Several studies have evaluated the effects of ospemifene on VVA and dyspareunia and indicate an improvement in subjective findings. Objective findings such as a decrease in pH and recovery of a premenopausal vaginal maturation index have been reported. Beneficial effects have also been demonstrated in bone. Evaluations of breast health support the safety of ospemifene, although data are limited to 1 year. Short-term risks appear to be limited and include the development of hot flushes. Until additional comparative studies of ospemifene and estrogens have been performed, ospemifene should be recommended for women with symptoms of VVA and dyspareunia who are unable to tolerate or unwilling to take local or systemic estrogens. In this review, current evidence for the safety and efficacy of ospemifene in the treatment of moderate-to-severe VVA and dyspareunia are evaluated.

Ospemifene, a non-oestrogen selective oestrogen receptor modulator for the treatment of vaginal dryness associated with postmenopausal vulvar and vaginal atrophy: a randomised, placebo-controlled, phase III trial

OBJECTIVE

To evaluate the efficacy and safety of ospemifene, a novel selective oestrogen receptor modulator, in the treatment of vaginal dryness in postmenopausal women with vulvovaginal atrophy (VVA).

STUDY DESIGN

A 12 week, multicentre, randomised, double-blind, parallel-group phase III study of women (40-80 years) with VVA and self-reported vaginal dryness as their most bothersome symptom.

MAIN OUTCOME MEASURES

The co-primary efficacy endpoints were the change from baseline to Week 12 in (1) percentage of parabasal cells in the maturation index (MI), (2) percentage of superficial cells in the MI, (3) vaginal pH, and (4) severity of vaginal dryness. Safety assessments included physical examination, cervical Papanicolaou test and clinical laboratory analyses. Endometrial thickness and histology was also assessed.

RESULTS

A total of 314 women were randomised to once-daily ospemifene 60 mg/day (n=160) or placebo (n=154). Significant improvements in the percentages of parabasal and superficial cells in the MI and vaginal pH were observed with ospemifene compared with placebo (p<0.001 for all parameters). The mean change from baseline in severity score of vaginal dryness reported by women receiving ospemifene compared with those receiving placebo approached statistical significance (p=0.080). Improvements in each of the four co-primary endpoints with ospemifene were statistically significant compared to placebo in the per protocol population. The majority of treatment-emergent adverse events were considered mild to moderate in severity.

CONCLUSIONS

Once-daily oral ospemifene 60 mg was effective for the treatment of VVA in postmenopausal women with vaginal dryness.

One-year long-term safety extension study of ospemifene for the treatment of vulvar and vaginal atrophy in postmenopausal women with a uterus

OBJECTIVE

The aim of this study was to assess the safety of ospemifene, a novel selective estrogen receptor modulator, for the treatment of vulvar and vaginal atrophy in postmenopausal women with a uterus.

METHODS

In this multicenter, randomized, double-blind, placebo-controlled, long-term safety extension study, nonhysterectomized women aged 40 to 80 years (n = 180) received daily oral doses of placebo, ospemifene 30 mg/day, or ospemifene 60 mg/day for 40 weeks (continued as blinded treatments from the initial 12-week pivotal efficacy study of ospemifene). The total treatment period was 52 weeks. Safety assessments included adverse events, cervical Papanicolaou tests, endometrial histology, endometrial thickness, gynecological examination, breast palpation, mammography, physical examination, and clinical safety laboratory assessments.

RESULTS

No clinically significant adverse changes in safety assessments were observed in any treatment group. Most treatment-emergent adverse events were mild or moderate in severity. Hot flushes, the most frequently occurring treatment-emergent adverse event related to the study drug, had a low discontinuation rate (1.6%). No study participants discontinued because of endometrial or cervical pathology; no endometrial findings were clinically meaningful. On week 52, more than 95% of endometrial biopsy samples either were classified as atrophic or inactive or had insufficient tissue for diagnosis. There were no treatment-emergent adverse events of pelvic organ prolapse or venous thromboembolism. No cases of endometrial hyperplasia or carcinoma were observed. Only three participants (1.7%) taking ospemifene experienced vaginal bleeding or spotting, which was self-limiting.

CONCLUSIONS

Daily doses of ospemifene 30 mg and ospemifene 60 mg yielded few treatment-emergent adverse events and demonstrated no significant endometrial changes during the 1-year treatment of vulvar and vaginal atrophy in postmenopausal women with a uterus.

Current and evolving approaches to individualizing estrogen receptor-based therapy for menopausal women

CONTEXT

Adding progestogens to estrogens changes the risk profile of hormonal therapy for menopausal women, and recent data support the need for progestogen-free options. Several current and evolving approaches to managing estrogen deficiency allow for progestogen omission. We review the mechanisms of estrogen activity and provide an overview of emerging and available estrogen receptor (ER)-based therapies.

EVIDENCE ACQUISITION

PubMed was searched for relevant English-language articles using keywords pertaining to estrogen deficiency, menopause, hormone therapy, and estrogen-only therapy. Pivotal or recent randomized controlled trials, large observational studies, comprehensive meta-analyses, and established therapeutic guidelines were compiled.

EVIDENCE SYNTHESIS

Advances in our understanding of ER pharmacology have led to therapies designed to optimize ER activity, including selective ER modulators (SERMs) and tissue-selective estrogen complexes (TSECs). Each estrogen, SERM, and TSEC exhibits a unique profile of tissue-specific activity, spanning the spectrum from ER agonism to antagonism. Systemic estrogens unopposed by progestogens effectively manage menopausal symptoms in hysterectomized postmenopausal women but require progestogen use in postmenopausal women with a uterus. SERMs are effective for managing certain aspects of estrogen deficiency in postmenopausal women, but data suggest that pairing a SERM with estrogens to form a TSEC provides a more optimal therapeutic profile for women with a uterus.

CONCLUSIONS

Treating signs and symptoms of estrogen deficiency requires an individualized approach based on a woman's goals and the purported risks of different therapies. New and emerging agents have demonstrated efficacy in postmenopausal women with a uterus, while allowing these women to avoid progestogens and their possible adverse effects.

Ospemifene, a novel selective estrogen receptor modulator for treating dyspareunia associated with postmenopausal vulvar and vaginal atrophy

OBJECTIVE

The aim of this work was to study the role of ospemifene, a novel selective estrogen receptor modulator, in the treatment of vulvar and vaginal atrophy in postmenopausal women with moderate to severe dyspareunia and physiological vaginal changes.

METHODS

This multicenter phase 3 study used a randomized, double-blind, parallel-group design to compare the efficacy, safety, and tolerability of oral ospemifene 60 mg/day versus placebo. A total of 605 women aged 40 to 80 years who self-reported a most bothersome symptom of dyspareunia and had a diagnosis of vulvar and vaginal atrophy were randomized to take a once-daily dose of ospemifene (n = 303) or placebo (n = 302) for 12 weeks.

RESULTS

Analysis of the intent-to-treat (n = 605) population found the efficacy of ospemifene to be significantly greater than that of placebo for each of the following coprimary endpoints: percentages of parabasal and superficial cells, vaginal pH, and severity of dyspareunia. With ospemifene, the percentage of parabasal cells and vaginal pH significantly decreased; the percentage of superficial cells significantly increased; and dyspareunia was significantly reduced versus placebo (all P < 0.0001, except for dyspareunia: P = 0.0001). Among the randomized women, 186 (61.4%) in the ospemifene group and 154 (51.0%) in the placebo group reported at least one treatment-emergent adverse event. Hot flushes were the most frequently reported treatment-related adverse event (ospemifene 6.6% vs placebo 3.6%); only one participant discontinued in each group. As determined by the investigators, no serious adverse events related to the study drug were reported.

CONCLUSIONS

In this study, once-daily oral ospemifene 60 mg was effective for the treatment of vulvar and vaginal atrophy in postmenopausal women with dyspareunia.

Long-term safety of ospemifene (52-week extension) in the treatment of vulvar and vaginal atrophy in hysterectomized postmenopausal women

OBJECTIVE

To examine the long-term safety of oral ospemifene, a non-estrogen tissue-selective estrogen agonist/antagonist, for the treatment of moderate to severe dyspareunia, a symptom of vulvar and vaginal atrophy (VVA) due to menopause.

STUDY DESIGN

This multicenter, long-term, open-label, safety extension study was conducted in women without a uterus aged 40-80 years (N=301) who received oral ospemifene 60 mg/day for 52 weeks. Participants either continued their 60-mg/day ospemifene dose from the initial 12-week pivotal efficacy study or switched from blinded placebo or ospemifene 30 mg/day to open-label ospemifene 60 mg/day. The 52-week open-label extension period plus initial 12-week treatment period totaled up to 64 weeks of ospemifene exposure. A 4-week posttreatment follow-up ensued (68 weeks total).

MAIN OUTCOME MEASURES

Safety assessments included adverse events, laboratory studies, physical and gynecologic examination, vital signs, breast palpation, and mammography.

RESULTS

Most treatment-emergent adverse events (TEAEs) during the extension study were mild or moderate in severity. The most common TEAE related to study drug was hot flushes (10%; leading to discontinuation for 2% of patients). One serious TEAE, a non-ST-elevation myocardial infarction in a patient with pre-existing cardiac disease, was considered possibly related to study medication. One mild breast-related TEAE, considered unrelated to study drug, was ongoing at study completion. There were no instances of pelvic organ prolapse, incontinence, venous thromboembolism, fractures, breast cancers or death. No clinically significant adverse changes were observed in other safety parameters.

CONCLUSIONS

Ospemifene is clinically safe and generally well tolerated in postmenopausal patients with dyspareunia, a symptom of VVA.

Tissue selectivity of ospemifene: pharmacologic profile and clinical implications

The multifactorial consequences of menopausal estrogen deficiency affect numerous tissues throughout the body. Supplemental hormonal therapies carry the burden of a risk/benefit ratio that must be highly individualized. Selective estrogen receptor modulators (SERMs) are estrogen receptor (ER) agonist/antagonists designed to induce benefits comparable with estrogen while minimizing adverse effects. Here, we review the estrogen agonist/antagonist profile of ospemifene, a novel triphenylethylene derivative recently approved to treat dyspareunia, a symptom of vulvar and vaginal atrophy (VVA) due to menopause, both preclinically and clinically. Ospemifene binds ERα and ERβ with approximately equal affinities. In preclinical models, ospemifene increased vaginal and uterine epithelial thickness and mucification to the same extent as estrogen. Ospemifene did not induce endometrial hyperplasia in animal models; there also was no stimulatory effect on endometrial cells. In rat and human mammary cells in vitro, ospemifene evokes a dose-dependent inhibition on estrogen-induced cell responses and cell proliferation, supporting an antiestrogenic effect in breast. In contrast, ospemifene has an estrogenic effect on bone, as seen by improved bone mineral density, strength, mass, and histomorphometry in preclinical models, consistent with improvements in markers of bone resorption and formation in postmenopausal women. Based on the preclinical evidence, ospemifene has beneficial estrogen-like effects on the vaginal epithelium, preliminary evidence to support a neutral endometrial profile, antiproliferative effects in breast, and estrogenic effects in bone. Taken together, especially regarding estrogen-like effects on the vaginal epithelium, ospemifene presents a profile of tissue-specific effects that appear novel among available SERMs and well-suited for the treatment of VVA.

Ospemifene 12-month safety and efficacy in postmenopausal women with vulvar and vaginal atrophy

Objective

Assessment of 12-month safety of ospemifene 60 mg/day for treatment of postmenopausal women with vulvar and vaginal atrophy (VVA).

Methods

In this 52-week, randomized, double-blind, placebo-controlled, parallel-group study, women 40–80 years with VVA and an intact uterus were randomized 6 : 1 to ospemifene 60 mg/day or placebo. The primary objective was 12-month safety, particularly endometrial; 12-week efficacy was assessed. Safety assessments included endometrial histology and thickness, and breast and gynecological examinations. Efficacy evaluations included changes from baseline to week 12 in percentage of superficial and parabasal cells and vaginal pH.

Results

Of 426 randomized subjects, 81.9% (n = 349) completed the study with adverse events the most common reason for discontinuation (ospemifene 9.5%; placebo 3.9%). Most (88%) treatment-emergent adverse events with ospemifene were considered mild or moderate. Three cases (1.0%) of active proliferation were observed in the ospemifene group. For one, active proliferation was seen at end of study week 52, and diagnosed as simple hyperplasia without atypia on follow-up biopsy 3 months after the last dose. This subsequently resolved with progestogen treatment and dilatation and curettage. In six subjects (five ospemifene (1.4%), one placebo (1.6%)) endometrial polyps were found (histopathology); however, only one (ospemifene) was confirmed as a true polyp during additional expert review. Endometrial histology showed no evidence of carcinoma. Statistically significant improvements were seen for all primary and secondary efficacy measures and were sustained through week 52 with ospemifene vs. placebo.

Conclusions

The findings of this 52-week study confirm the tolerance and efficacy of oral ospemifene previously reported in short- and long-term studies.

Vaginal effects of ospemifene in the ovariectomized rat preclinical model of menopause

Ospemifene is a unique tissue-selective estrogen agonist/antagonist (also known as a selective estrogen receptor modulator [SERM]) with demonstrated efficacy in Phase 3 studies of postmenopausal women with vulvar and vaginal atrophy (VVA). This report describes preclinical studies on the effects of ospemifene in the ovariectomized (OVX) rat model of menopause. Ospemifene (10mg/kg/day) and the SERM comparator, raloxifene (10mg/kg/day) were administered for 2 weeks and both increased vaginal weight; ospemifene was more effective than raloxifene. In addition, ospemifene had a greater effect on increasing vaginal epithelial height compared with raloxifene. The effect on uterine weight was less pronounced for both ospemifene and raloxifene. The ED50 of ospemifene on vaginal epithelial height was 0.39mg/kg/day and the magnitude was nearly the same as was seen with the positive control, 17α-ethinyl estradiol (EE2). In a histological analysis of ospemifene-treated rat vaginas, basal cells were overlaid by 2 to 3 cell layers of thickened goblet-like mucified cells apically; however, the cornification observed with EE2 was absent. Estrogenic activity of ospemifene was confirmed by upregulation of progesterone receptors in vaginal epithelium and stroma. Ospemifene showed similar affinity for estrogen receptor (ER)-α and ER-β, but an overall lower affinity than estradiol. Ospemifene antagonized estrogen response element (ERE)-mediated transactivation on MCF-7 cells, confirming its anti-estrogenic activity in breast cancer cells. The dose response for ospemifene in the rat is consistent with that observed in clinical studies of ospemifene 30 and 60mg, showing that the OVX rat is a highly predictive model of SERM activity in postmenopausal VVA.

Ospemifene for the treatment of dyspareunia associated with vulvar and vaginal atrophy: potential benefits in bone and breast

Ospemifene is a selective estrogen receptor modulator (SERM), or estrogen receptor agonist/antagonist, that was recently approved by the US Food and Drug Administration for the treatment of dyspareunia associated with vulvar and vaginal atrophy, a chronic condition that affects up to 60% of postmenopausal women. Ospemifene is the first and only nonestrogen compound approved for this indication. Compared with other approved SERMs, such as tamoxifen, toremifene, bazedoxifene, and raloxifene, the estrogen-like effects of ospemifene in the vaginal epithelium are unique. This review first discusses the rationale for developing ospemifene, including its mechanism of action, and then focuses on the clinical development of ospemifene for the treatment of dyspareunia associated with vulvar and vaginal atrophy. Included are discussions of the effects of ospemifene on the endometrium, serum lipids, coagulation markers, bone, and breast cancer. In conclusion, ospemifene is a SERM with a unique estrogen agonist/antagonist tissue profile that was recently approved in the US for the treatment of dyspareunia associated with vulvar and vaginal atrophy in postmenopausal women. Ospemifene warrants further clinical investigation for the treatment and prevention of osteoporosis and breast cancer.

Profile of ospemifene in the breast

Vulvar and vaginal atrophy (VVA) is a chronic, progressive medical condition prevalent among postmenopausal women, which produces symptoms such as dyspareunia, vaginal dryness, and vaginal irritation. Currently, the only prescription options are systemic and vaginal estrogen therapies that may be limited by concerns about long-term safety and breast cancer risk. Ospemifene is a tissue-selective estrogen agonist/antagonist (a selective estrogen receptor modulator) recently approved by the US Food and Drug Administration for treatment of dyspareunia, a symptom of VVA, due to menopause. Ospemifene, the first nonestrogen oral treatment for this indication, may provide an alternative to treatment with estrogen. Animal models with ospemifene suggest an inhibitory effect on growth of malignant breast tissue, but animal data cannot necessarily be extrapolated to humans. Clinical trials, including 3 long-term studies assessing the overall safety of ospemifene, support that ospemifene is generally well tolerated, with beneficial effects on the vagina, neutral effects on the breast, and minimal effects on the endometrium.

The discovery and development of selective estrogen receptor modulators (SERMs) for clinical practice

Selective estrogen receptor modulators (SERMs) are structurally different compounds that interact with intracellular estrogen receptors in target organs as estrogen receptor agonists or antagonists. These drugs have been intensively studied over the past decade and have proven to be a highly versatile group for the treatment of different conditions associated with postmenopausal women's health, including hormone responsive cancer and osteoporosis. Tamoxifen, a failed contraceptive is currently used to treat all stages of breast cancer, chemoprevention in women at high risk for breast cancer and also has beneficial effects on bone mineral density and serum lipids in postmenopausal women. Raloxifene, a failed breast cancer drug, is the only SERM approved internationally for the prevention and treatment of postmenopausal osteoporosis and vertebral fractures. However, although these SERMs have many benefits, they also have some potentially serious adverse effects, such as thromboembolic disorders and, in the case of tamoxifen, uterine cancer. These adverse effects represent a major concern given that long-term therapy is required to prevent osteoporosis or prevent and treat breast cancer. The search for the 'ideal' SERM, which would have estrogenic effects on bone and serum lipids, neutral effects on the uterus, and antiestrogenic effects on breast tissue, but none of the adverse effects associated with current therapies, is currently under way. Ospemifene, lasofoxifene, bazedoxifene and arzoxifene, which are new SERM molecules with potentially greater efficacy and potency than previous SERMs, have been investigated for use in the treatment and prevention of osteoporosis. These drugs have been shown to be comparably effective to conventional hormone replacement therapy in animal models, with potential indications for an improved safety profile. Clinical efficacy data from ongoing phase III trials are available or are awaited for each SERM so that a true understanding of the therapeutic potential of these compounds can be obtained. In this article, we describe the discovery and development of the group of medicines called SERMs. The newer SERMs in late development: ospemifene, lasofoxifene, bazedoxifene, are arzoxifene are described in detail.

Maturitas. 2013;Jan 15; Epub ahead of print. [PMID: 23332519 DOI: 10.1016/j.maturitas.2012.12.002]

The incidence and severity of vulvovaginal atrophy (VVA) in postmenopausal breast cancer patients has a significant impact on quality of life. While the etiology of VVA is primarily related to low estrogen levels seen in menopause, women with breast cancer have an added risk of VVA induced by a combination of chemotherapy, hormonal therapy, and menopause. Ospemifene is a new, non-hormonal selective estrogen receptor modulator (SERM) triphenylethylene derivative that is effective in treating VVA in postmenopausal women. Although other SERMs have antagonistic effects on the vagina, ospemifene exerts an estrogen-like effect on the vaginal epithelium. This review will focus on data demonstrating the antiestrogenic activity of ospemifene in several unique breast cancer animal models, and the implications for utilizing ospemifene in patients with breast cancer suffering from VVA. Additional research addressing the expanded use of ospemifene in breast cancer patients is also warranted.

Ospemifene and 4-hydroxyospemifene effectively prevent and treat breast cancer in the MTag.Tg transgenic mouse model

OBJECTIVE

Ospemifene, a new drug indicated for the treatment of vulvovaginal atrophy, has completed phase III clinical trials. A condition affecting millions of women worldwide, vulvovaginal atrophy has long been treated with estrogen therapy. Estrogen treatment carries with it risks of thromboembolism, endometrial proliferative effects, and breast cancer promotion. In this study, we test the effects of three dosing levels of ospemifene in both the prevention and treatment of breast cancer in the MTag.Tg mouse model.

METHODS

The polyomavirus middle-T transgenic mouse model (MTag.Tg), which produces synchronized, multifocal mammary tumors in the immunologically intact C57BL/6 background, was used to examine the impact of ospemifene treatment. First, a cell line derived from an MTag.Tg mouse tumor (MTag 34) was treated in vitro with ospemifene and its major metabolite, 4-hydroxyospemifene (4-OH ospemifene). MTag.Tg mice were treated daily by gavage with three different doses of ospemifene (5, 25, and 50 mg/kg) before or after the development of mammary tumors. Survival and tumor development results were used to determine the effect of ospemifene treatment on mammary tumors in both the preventive and treatment settings.

RESULTS

Tumors and the MTag 34 cell line were positive for estrogen receptor expression. The MTag 34 line was not stimulated by ospemifene or its major, active metabolite 4-OH ospemifene in vitro. Ospemifene increased survival time and exerted an antitumor effect on the development and growth of estrogen receptor-positive mammary tumors in the MTag.Tg mouse model at the 50-mg/kg dose. The levels of ospemifene and 4-OH ospemifene in both the tumors and plasma of mice confirmed the dosing. Ospemifene did not exert an estrogenic effect in the breast tissue at doses equivalent to human dosing.

CONCLUSIONS

Ospemifene prevents and treats estrogen receptor-positive MTag.Tg mammary tumors in this immune-intact mouse model in a dose-dependent fashion. Ospemifene drug levels in the plasma of treated mice were comparable with those found in humans. Combined with our previous data, ospemifene does not seem to pose a breast cancer risk in animals and slows down cancer development and progression in the MTag.Tg model.

Ospemifene effectively treats vulvovaginal atrophy in postmenopausal women: results from a pivotal phase 3 study

OBJECTIVE

The aim of this study was to study the efficacy and safety of ospemifene, a new selective estrogen receptor modulator, in the treatment of vulvovaginal atrophy in postmenopausal women.

METHODS

A randomized, double-blind phase 3 study in which 826 postmenopausal women were randomized 1:1:1 to receive treatment with ospemifene 30 or 60 mg/day or placebo orally for 12 weeks was conducted. The primary inclusion criteria were having 5% or less superficial cells on the vaginal smear (maturation index), vaginal pH greater than 5.0, and at least one moderate or severe symptom of vulvovaginal atrophy. The four coprimary endpoints were the change from baseline to 12 weeks in the percentage of superficial and parabasal cells on the vaginal smear, change in vaginal pH, and change in severity of most bothersome symptom (vaginal dryness or dyspareunia) compared with placebo. All participants were given a nonhormonal vaginal lubricant for use as needed.

RESULTS

Ospemifene was statistically significantly superior to placebo in each of the coprimary endpoints at the 60-mg dose. Statistically significant results were achieved for all coprimary endpoints with the 30-mg dose except for dyspareunia. Ospemifene was well tolerated at both doses and demonstrated a favorable safety profile.

CONCLUSIONS

Ospemifene was shown to be effective and well tolerated for the treatment of the symptoms of vaginal dryness and dyspareunia associated with vulvovaginal atrophy over and above the use of provided lubricants.

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.