Toremifene: an evaluation of its safety profile

Female Gene Networks Are Expressed in Myofibroblast-Like Smooth Muscle Cells in Vulnerable Atherosclerotic Plaques

BACKGROUND

Women presenting with coronary artery disease more often present with fibrous atherosclerotic plaques, which are currently understudied. Phenotypically modulated smooth muscle cells (SMCs) contribute to atherosclerosis in women. How these phenotypically modulated SMCs shape female versus male plaques is unknown.

METHODS

Gene regulatory networks were created using RNAseq gene expression data from human carotid atherosclerotic plaques. The networks were prioritized based on sex bias, relevance for smooth muscle biology, and coronary artery disease genetic enrichment. Network expression was linked to histologically determined plaque phenotypes. In addition, their expression in plaque cell types was studied at single-cell resolution using single-cell RNAseq. Finally, their relevance for disease progression was studied in female and male Apoe-/- mice fed a Western diet for 18 and 30 weeks.

RESULTS

Here, we identify multiple sex-stratified gene regulatory networks from human carotid atherosclerotic plaques. Prioritization of the female networks identified 2 main SMC gene regulatory networks in late-stage atherosclerosis. Single-cell RNA sequencing mapped these female networks to 2 SMC phenotypes: a phenotypically modulated myofibroblast-like SMC network and a contractile SMC network. The myofibroblast-like network was mostly expressed in plaques that were vulnerable in women. Finally, the mice ortholog of key driver gene MFGE8 (milk fat globule EGF and factor V/VIII domain containing) showed retained expression in advanced plaques from female mice but was downregulated in male mice during atherosclerosis progression.

CONCLUSIONS

Female atherosclerosis is characterized by gene regulatory networks that are active in fibrous vulnerable plaques rich in myofibroblast-like SMCs.

Female gene networks are expressed in myofibroblast-like smooth muscle cells in vulnerable atherosclerotic plaques

Women presenting with coronary artery disease (CAD) more often present with fibrous atherosclerotic plaques, which are currently understudied. Phenotypically modulated smooth muscle cells (SMCs) contribute to atherosclerosis in women. How these phenotypically modulated SMCs shape female versus male plaques is unknown. Here, we show sex-stratified gene regulatory networks (GRNs) from human carotid atherosclerotic tissue. Prioritization of these networks identified two main SMC GRNs in late-stage atherosclerosis. Single-cell RNA-sequencing mapped these GRNs to two SMC phenotypes: a phenotypically modulated myofibroblast-like SMC network and a contractile SMC network. The myofibroblast-like GRN was mostly expressed in plaques that were vulnerable in females. Finally, mice orthologs of the female myofibroblast-like genes showed retained expression in advanced plaques from female mice but were downregulated in male mice during atherosclerosis progression. Female atherosclerosis is driven by GRNs that promote a fibrous vulnerable plaque rich in myofibroblast-like SMCs.

Selective Estrogen Receptor Modulators in Gynecology Practice

Selective estrogen receptor (ER) modulators have variable tissue specific estrogen agonist and antagonist activities. Tamoxifen is approved for treatment and prevention of breast cancer; acts as an endometrial estrogen agonist. Raloxifene is approved for prevention and treatment of osteoporosis and prevention of breast cancer. The selective ER modulators bazedoxifene paired with conjugated estrogens relieves vasomotor symptoms and prevents bone loss with neutral effects on breast and amenorrhea similar to placebo. Ospemifene is approved to treat dyspareunia. Lasofoxifene is in development for resistant ER positive breast cancer. Estetrol (E4), synthesized by human fetal liver, has dual weak-estrogenic/antiestrogenic features, now approved as a contraceptive.

Estrogen Receptors as Molecular Targets of Endocrine Therapy for Glioblastoma

Hormonal factors may participate in the development and progression of glioblastoma, the most aggressive primary tumor of the central nervous system. Many studies have been conducted on the possible involvement of estrogen receptors (ERs) in gliomas. Since there is a tendency for a reduced expression of ERs as the degree of malignancy of such tumors increases, it is important to understand the role of these receptors in the progression and treatment of this disease. ERs belong to the family of nuclear receptors, although they can also be in the plasmatic membrane, cytoplasm and mitochondria. They are classified as estrogen receptors alpha and beta (ER⍺ and ERβ), each with different isoforms that have a distinct function in the organism. ERs regulate multiple physiological and pathological processes through the activation of genomic and nongenomic pathways in the cell. Nevertheless, the role of each isoform in the development and progression of glioblastoma is not completely clear. Diverse in vitro and in vivo studies have shown encouraging results for endocrine therapy as a treatment for gliomas. At the same time, many questions have arisen concerning the nature of ERs as well as the mechanism of action of the proposed drugs. Hence, the aim of the current review is to describe the drugs that could possibly be utilized in endocrine therapy for the treatment of high-grade gliomas, analyze their interaction with ERs, and explore the involvement of these drugs and receptors in resistance to standard chemotherapy.

Risk of Stroke in Patients with Breast Cancer and Sleep Disorders

Breast cancer and stroke were leading cause of cancer-related mortality in the world. Stroke is the second leading cause of death. Previous studies showed that patients with breast cancer had a relatively higher risk of sleep disorders. Sleep disorders increased the risk of stroke. The aim of our study was to examine the risk of stroke after a breast cancer with sleep disorder among women in Taiwan. The Taiwan Cancer Registry was used to identify patients with breast cancer. Patients with new-onset breast cancer from January 2007 to December 2015 were selected for this study and followed until December 31, 2017. Patients who were diagnosed with sleep disorders were set as the case group, and the controls were those without sleep disorders. We enrolled 5256 patients with sleep disorders and 10,512 patients without sleep disorders. There were 121 (2.30%) patients with ischemic stroke among the breast cancer patients with sleep disorders. The mean time from the diagnosis of breast cancer to the occurrence of ischemic stroke was 6.29±2.59 years for breast cancer patients with sleep disorders and 6.00±2.76 years for those without sleep disorders (p < 0.0001). After matching by age and index year, breast patients with sleep disorders had a 1.31-fold higher risk (95% confidence interval: 1.03-1.66; p-value=0.026) of ischemic stroke than those without sleep disorders, after adjustment for comorbidities, cancer clinical stage, and treatment types. In conclusion, Breast cancer patients with sleep disorders have an increased risk of stroke.

Recent Advancement in the One-Pot Synthesis of the Tri-Substituted Methanes (TRSMs) and Their Biological Applications

The history of tri-substituted methanes (TRSMs) in chemical industries is much older. Tri-substituted methanes were previously used as dyes in the chemical industries. Still, there is a significant surge in researchers' interest in them due to their wide range of bioactivities. Tri-substituted methane derivatives show a wide range of biological activities like anti-tumor, antimicrobial, antibiofilm, antioxidant, anti-inflammatory, anti-arthritic activities. Due to the wide range of medicinal applications shown by tri-substituted methanes, most of the methodologies reported in the literature for the synthesis of TRSMs are focused on the one-pot method. This review explored the recently reported one-pot processes for synthesizing tri-substituted methanes and their various medicinal applications. Based on the substitution attached to the -CH carbon, this review categorizes them into two major classes: (I) symmetrical and (II) unsymmetrical trisubstituted methanes. In addition, this review gives an insight into the growing opportunities for the construction of trisubstituted scaffolds via one-pot methodologies. To the best of our knowledge, no one has yet reported a review on the one-pot synthesis of TRSMs. Therefore, here we present a brief literature review of the synthesis of both symmetrical and unsymmetrical TRSMs covering various one-pot methodologies along with their medicinal applications.

Acupuncture for mammary gland hyperplasia: A Bayesian network meta-analysis protocol

BACKGROUND

Multiple randomized controlled trials have shown that acupuncture (ACU) work well in the treating mammary gland hyperplasia, which has been widely used in hospitals of China. Although the choices of ACU treatments varies in practice, most are based on experience or preference. Therefore, we outline a plan to assess and rank the efficacy of the various ACU methods to formulate a prioritized regimen for mammary gland hyperplasia in ACU therapy.

METHODS

We will make a comprehensive retrieval in 7 databases as following: PubMed, Embase, Cochrane Library, China BioMedical Literature, China National Knowledge Infrastructure, Chinese Scientific Journals Database, and Wanfang database. The time is limited from the construction of the library to June 2020. We will evaluate the quality and the evidence of the included randomized controlled trials by the risk of bias tool and grading of recommendations assessment, development and evaluation, respectively. Bayesian network meta-analysis will be conducted using Stata16.0 and WinBUGS V.1.4.3.

RESULTS

The results of this study will be published in a peer-reviewed journal.

CONCLUSIONS

Our study is expected to provide high-quality, evidence-based recommendations on further treatment of MGH for clinicians.

REGISTRATION

PROSPERO (registration number CRD42020158743).

Beyond estrogen: advances in tissue selective estrogen complexes and selective estrogen receptor modulators

Selective estrogen receptor modulators (SERMs) are synthetic non-steroidal agents which have variable estrogen agonist and antagonist activities in different target tissues. Tamoxifen is an anti-estrogen in the breast used for treatment and prevention of breast cancer, with estrogen agonist activity in the uterus. Raloxifene prevents and treats osteoporosis and prevents breast cancer, and can be safely combined with vaginal but not systemic estrogen. The tissue selective estrogen complex combines conjugated equine estrogens (CEE) with the SERM bazedoxifene (BZA). The five Selective Estrogen Menopause and Response to Therapy studies, with up to 2 years of data, demonstrated that CEE/BZA 0.45 mg/BZA 20 mg improved vasomotor symptoms and vulvovaginal atrophy, prevented bone loss, and was neutral on breast tenderness, breast density, with breast cancer incidence similar to placebo. Protection against estrogen-induced endometrial hyperplasia and cancer was found, with similar amenorrhea rates to placebo. Ospemifene is approved to treat dyspareunia, with potential benefits on bone and the breast, while lasofoxifene is being developed to treat resistant estrogen receptor-positive breast cancer in women. Estetrol is an estrogen synthesized exclusively during pregnancy by the human fetal liver and initially considered a weak estrogen, but it appears to have dual weak estrogenic/anti-estrogenic features.

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.

Serum lipid and bone metabolism effects of Toremifene vs. Letrozole as adjuvant therapy for postmenopausal early breast cancer patients: results of a multicenter open randomized study

A prospective randomized phase II trial was conducted to evaluate the time course effects of toremifene (TOR) and letrozole (LET), as adjuvant hormone therapy, on serum lipid profiles and bone metabolism in estrogen receptor (ER)-positive, postmenopausal breast cancer patients.Fifty-four postmenopausal breast cancer patients [ER positive, HER2 negative, T1–2, node metastases (n = 0–3), M0] who had undergone curative resection were enrolled. They were randomized to receive either TOR 40 mg/day or LET 2.5 mg/day as adjuvant hormone therapy. Serum lipids and bone markers were measured prior to, and again at 6, 12, and 24 months after initiation of treatment. Changes in serum lipids and bone markers were compared. Serum levels of total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) were decreased compared with the baseline values at 6 months in 6.5 and 14.0% of patients, respectively, receiving TOR. Lipid levels did not change in patients administered LET. Significant differences were observed in TC and LDL-C between the two groups at 12 and 24 months. In the TOR group, serum bone-specific alkaline phosphatase (BAP) was decreased by 25.0% at 12 months, and serum cross-linked N-telopeptide of type-I collagen (NTx) was decreased by 13.6% at 6 months, and these reductions were maintained for at least 24 months. In contrast, in the LET group, serum BAP did not change and NTx was increased by 16.0% at 6 months and by 18.6% at 24 months, as compared with the baseline.TOR and LET exert different effects on serum lipid profiles and bone metabolism markers. The effects of TOR, as adjuvant hormone therapy, on both lipids and bone metabolism in postmenopausal breast cancer patients are superior to those of LET.

Acid promoted Ir–P^N complex catalyzed hydrogenation of heavily hindered 3,4-diphenyl-1,2-dihydronaphthalenes: asymmetric synthesis of lasofoxifene tartrate

An asymmetric hydrogenation of minimally functionalized tetrasubstituted cyclic olefins has been developed using an Ir–P^N catalyst and an acid additive enabling the synthesis of lasofoxifene tartrate.

Clinical significance of fatty liver disease induced by tamoxifen and toremifene in breast cancer patients

BACKGROUND AND AIM

The aim of this study was to identify the effect of selective estrogen receptor modulator (SERM) on non-alcoholic fatty liver disease (NAFLD) in Asian women.

METHODS

We retrospectively evaluated fatty liver development and/or serum alanine aminotransferase (ALT) elevation during SERM treatment in 1061 women who were diagnosed and treated with breast cancer in 2005 at Asan Medical Center.

RESULTS

45 of 618 SERM-treated patients with normal ALT at baseline experienced ALT elevation during SERM treatment. Among the 112 SERM-treated patients who underwent liver imaging test, fatty liver was observed in 47 and both fatty liver and ALT elevation developed in 16 of 102 SERM-treated patients with normal baseline ALT. The cumulative rates of ALT elevation (10.7 vs. 4.3%; P = 0.002), fatty liver (48.5 vs. 20.9%; P < 0.001), and both fatty liver and ALT elevation (17.7 vs. 7.1%; P = 0.02) at 60 months were significantly higher in the SERM group than non-SERM group. By multivariate analysis, SERM treatment increased the risk of ALT elevation (hazard ratio [HR], 2.20; P = 0.01), fatty liver development (HR, 3.59; P < 0.001), and both fatty liver and ALT elevation (HR, 4.98; P = 0.01). After discontinuation of SERM, elevated serum ALT normalized in 39 (92.9%) and there were no instances of liver-related death or progression to liver cirrhosis in patients who experienced fatty liver or ALT elevation.

CONCLUSIONS

Although SERM treatment is significantly associated with NAFLD in Asian women, considering the tolerability and reversibility of NAFLD induced by SERM, it can be continued with liver function monitoring in relevant patients.

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.

Toremifene in the treatment of breast cancer

Although more widespread screening and routine adjuvant therapy has improved the outcome for breast cancer patients in recent years, there remains considerable scope for improving the efficacy, safety and tolerability of adjuvant therapy in the early stage disease and the treatment of advanced disease. Toremifene is a selective estrogen receptor modifier (SERM) that has been widely used for decades in hormone receptor positive breast cancer both in early and late stage disease. Its efficacy has been well established in nine prospective randomized phase III trials compared to tamoxifen involving more than 5500 patients, as well as in several large uncontrolled and non-randomized studies. Although most studies show therapeutic equivalence between the two SERMs, some show an advantage for toremifene. Several meta-analyses have also confirmed that the efficacy of toremifene is at least as good as that of tamoxifen. In terms of safety and tolerability toremifene is broadly similar to tamoxifen although there is some evidence that toremifene is less likely to cause uterine neoplasms, serious vascular events and it has a more positive effect on serum lipids than does tamoxifen. Toremifene is therefore effective and safe in the treatment of breast cancer. It provides not only a useful therapeutic alternative to tamoxifen, but may bring specific benefits.

Use of SERMs for treatment in postmenopausal women

Selective estrogen receptor modulators (SERMs) are synthetic non-steroidal agents which have varying estrogen agonist and antagonist activities in different tissues, most likely due to the receptor conformation changes associated with that SERM's binding and the subsequent effect on transcription. Clinical trials aim to differentiate amongst SERMs on selected target tissues for use in postmenopausal women including effects on breast, bone, cardiovascular venous thrombosis risk, endometrium, vagina, vasomotor symptoms, and brain. This paper describes differences in clinical effects on selected target tissues of SERMs that are approved, discontinued or in development. FDA approved SERMs include tamoxifen and toremifene used for prevention and treatment of breast cancer, raloxifene approved for prevention and treatment of osteoporosis and prevention of invasive breast cancer, and ospemifene approved for treatment of dyspareunia from menopausal vaginal atrophy. The FDA approved first tissue selective estrogen complex (TSEC) a pairing of conjugated equine estrogens with the SERM, bazedoxifene. This pairing reduces the risk of endometrial hyperplasia that can occur with the estrogenic component of the TSEC without the need for a progestogen in women with a uterus. It also allows for the estrogenic benefits on relief of hot flashes and prevention of bone loss without stimulating the breast or the endometrium. In clinical practice, the tissue-selective actions of SERMs, alone or paired with estrogens, allow for individualization in meeting the treatment needs of postmenopausal women by providing targeted tissue effects. This article is part of a Special Issue entitled 'Menopause'.

Efficacy and tolerability of toremifene and tamoxifen therapy in premenopausal patients with operable breast cancer: a retrospective analysis

BACKGROUND

Given the use of tamoxifen as standard treatment for hormone receptor-positive breast cancer, the use of toremifene as an adjuvant endocrine therapy has not been widely examined. The present retrospective study compared the efficacy and safety of toremifene and tamoxifen in the treatment of operable hormone receptor-positive breast cancer in premenopausal women.

METHODS

Premenopausal patients with hormone receptor- positive operable breast cancer were eligible. Enrolled patients (n = 1847) received either 60 mg toremifene (n = 396) or 20 mg tamoxifen (n = 1451) daily for a minimum of 5 years after surgery. Disease-free survival (dfs) was the primary endpoint. Overall survival (os) and time to distant recurrence were secondary endpoints.

RESULTS

Treatment with toremifene and tamoxifen resulted in no between-group differences in dfs (p = 0.659) or os (p = 0.364). Mean dfs was 10.3 years for both groups. Mean os was 11.2 years for the toremifene group and 11.1 years for tamoxifen group. The 5-year dfs rate was 87.0% in the toremifene group and 85.0% in the tamoxifen group. The 5-year survival rate was 94.3% in the toremifene group and 93.5% in the tamoxifen group. Adverse events rates were similar in the two groups, with the exception of irregular menses, which occurred at a higher rate in the tamoxifen group than in the toremifene group (10.0% vs. 6.3%, p = 0.025).

CONCLUSIONS

In this retrospective study, the efficacy and safety profiles of toremifene and tamoxifen for the treatment of operable hormone receptor-positive breast cancer in premenopausal women were similar.

Toxicity and adverse effects of Tamoxifen and other anti-estrogen drugs

Breast cancer is a heterogeneous disease affecting thousands of people every year. Multiple factors are responsible in causing breast cancer while a number of treatment options are also available for the disease. Tamoxifen is the most widely used anti-estrogen for the treatment of hormone-dependent breast cancer. The specific drug is used as a hormonal therapy for patients who exhibit estrogen receptor positive breast cancer. The pharmacological activity of Tamoxifen is dependent on its conversion to its active metabolite, endoxifen, by CYP2D6. Tamoxifen reduces the risk of recurrence and death from breast cancer when given as adjuvant therapy and provides effective palliation for patients with metastatic breast cancer. In this review we focus on the role of Tamoxifen in breast cancer treatment including mechanisms and side-effects. Finally, we discuss in detail the exciting prospects that lie ahead.

Phase III randomized trial of toremifene versus tamoxifen for Japanese postmenopausal patients with early breast cancer

BACKGROUND

Toremifene, a selective estrogen receptor modulator, is used as adjuvant therapy for postmenopausal patients with breast cancer in Japan. For Japanese patients, however, only limited data are available on the efficacy and safety profile of toremifene. To establish the long term efficacy and safety of toremifene for Japanese patients, we conducted a prospective, multicenter, randomized phase III trial comparing toremifene and tamoxifen.

PATIENTS AND METHODS

The subjects were postmenopausal Japanese patients who had undergone surgery for node-negative breast cancer. Toremifene or tamoxifen was administered for 2 years. The primary endpoint was demonstration of the non-inferiority of toremifene compared with tamoxifen in respect of 5-year survival. Secondary endpoints were cumulative overall survival, cumulative disease-free survival, effects on lipid profiles, and adverse events.

RESULTS

A total of 253 patients were enrolled. The baseline characteristics of the two treatment groups were well-balanced. Median follow-up was 66.5 months. Five-year survival was similar for toremifene and tamoxifen (97.0 vs. 96.9 %; 90 % confidence interval -3.9 to 4.1), indicating that toremifene is not inferior to tamoxifen for postmenopausal Japanese patients with early breast cancer. Cumulative overall survival and cumulative disease-free survival were also very similar for toremifene and tamoxifen (97.5 vs. 97.3 %, log-rank test P = 0.9458; 88.4 vs. 90.6 %, log-rank test P = 0.3359, respectively). Adverse events in both groups were similar and mostly mild or moderate. Thus, both are equally effective and well tolerated.

CONCLUSION

Our results suggest that the efficacy and safety of toremifene and tamoxifen are equivalent for postmenopausal Japanese patients with early breast cancer.

Low-grade endometrial stromal sarcoma developing in a postmenopausal woman under toremifene treatment for breast cancer

Low-grade endometrial stromal sarcoma (ESS) is a rare neoplasm that is generally estrogen-receptor- and progesterone-receptor-positive and develops in premenopausal women. Although tamoxifen treatment is associated with an increased risk of ESS, the effect of other selective estrogen receptor modulators, including toremifene, on the risk of ESS is not clear. A 61-year-old postmenopausal woman was treated with toremifene as an adjuvant therapy for breast cancer. A cystic mass developed during the treatment, with gradual growth in the uterine myometrium. The patient was treated with hysterectomy and bilateral salpingo-oophorectomy, and the tumor was diagnosed as low-grade ESS (stage IA) with estrogen-receptor and progesterone-receptor. The patient discontinued toremifene and has been progression-free for 21 months. Our data suggest that toremifene might be associated with the development of ESS in certain patients through its estrogen-like effects in the uterus.

A comparison of survival outcomes and side effects of toremifene or tamoxifen therapy in premenopausal estrogen and progesterone receptor positive breast cancer patients: a retrospective cohort study

BACKGROUND

In premenopausal women, endocrine adjuvant therapy for breast cancer primarily consists of tamoxifen alone or with ovarian suppressive strategies. Toremifene is a chlorinated derivative of tamoxifen, but with a superior risk-benefit profile. In this retrospective study, we sought to establish the role of toremifene as an endocrine therapy for premenopausal patients with estrogen and/or progesterone receptor positive breast cancer besides tamoxifen.

METHODS

Patients with early invasive breast cancer were selected from the breast tumor registries at the Sun Yat-Sen Memorial Hospital (China). Premenopausal patients with endocrine responsive breast cancer who underwent standard therapy and adjuvant therapy with toremifene or tamoxifen were considered eligible. Patients with breast sarcoma, carcinosarcoma, concurrent contralateral primary breast cancer, or with distant metastases at diagnosis, or those who had not undergone surgery and endocrine therapy were ineligible. Overall survival and recurrence-free survival were the primary outcomes measured. Toxicity data was also collected and compared between the two groups.

RESULTS

Of the 810 patients reviewed, 452 patients were analyzed in the study: 240 received tamoxifen and 212 received toremifene. The median and mean follow up times were 50.8 and 57.3 months, respectively. Toremifene and tamoxifen yielded similar overall survival values, with 5-year overall survival rates of 100% and 98.4%, respectively (p = 0.087). However, recurrence-free survival was significantly better in the toremifene group than in the tamoxifen group (p = 0.022). Multivariate analysis showed that recurrence-free survival improved independently with toremifene (HR = 0.385, 95% CI = 0.154-0.961; p = 0.041). Toxicity was similar in the two treatment groups with no women experiencing severe complications, other than hot flashes, which was more frequent in the toremifene patients (p = 0.049). No patients developed endometrial cancer.

CONCLUSION

Toremifene may be a valid and safe alternative to tamoxifen in premenopausal women with endocrine-responsive breast cancer.

Pharmacokinetic evaluation of toremifene and its clinical implications for the treatment of osteoporosis

INTRODUCTION

Toremifene is a triphenylethylene selective estrogen receptor modulator (SERM) that differs from tamoxifen in a single chloride ion addition on a side chain, resulting in a potentially more favorable toxicity profile.

AREAS COVERED

This article reviews the pharmacokinetics of toremifene and its potential use for the treatment of osteoporosis. This article was based on articles found through a literature search containing the terms 'toremifene' and 'SERMs.'

EXPERT OPINION

Toremifene can be administered orally with an excellent bioavailability. The overall pharmacokinetic profile is remarkably similar to tamoxifen. Toremifene is highly metabolized in the liver and is eliminated primarily in the feces following enterohepatic circulation. Some of its metabolites retain biological activity. This SERM was approved by the FDA for the treatment of estrogen receptor-positive metastatic breast cancer and is under investigation for its potential skeletal benefits in men on androgen deprivation therapy. Despite the positive preclinical and clinical evidences for the prevention of bone loss and fractures, the chemopreventive effect on prostate cancer remains to be confirmed and an increased risk of venous thromboembolism was evidenced in a large Phase III trial. Thus, additional data are required to establish the full clinical profile of this compound and its potential advantages over antiresorptive agents commonly in use for the treatment of osteoporosis.

Cardiotoxicity of molecularly targeted agents

Cardiac toxicity of molecularly targeted cancer agents is increasingly recognized as a significant side effect of chemotherapy. These new potent therapies may not only affect the survival of cancer cells, but have the potential to adversely impact normal cardiac and vascular function. Unraveling the mechanisms by which these therapies affect the heart and vasculature is crucial for improving drug design and finding alternative therapies to protect patients predisposed to cardiovascular disease. In this review, we summarize the classification and side effects of currently approved molecularly targeted chemotherapeutics.

Effects of toremifene and anastrozole on serum lipids and bone metabolism in postmenopausal females with estrogen receptor-positive breast cancer: the results of a 2-year multicenter open randomized study

The potential long-term adverse effects on quality of life have to be considered when selecting agents for adjuvant hormonal treatment for postmenopausal patients with estrogen receptor-positive breast cancer. We performed a 2-year multicenter randomized study to assess the differences in the time course effects between toremifene (TOR) and anastrozole (ANA) on serum lipid profiles and bone metabolism. This study assessed the serum levels of triglycerides (TG), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), apolipoprotein A-1 (Apo A1), and apolipoprotein B (Apo B) as lipid profiles and bone-specific alkaline phosphatase (BAP) and the N-telopeptide of type-I collagen (NTX) as bone turnover markers in patients who received daily doses of 40 mg and 1 mg for TOR and ANA, respectively. A decreased serum level of TC, LDL-C, and Apo B was, respectively, observed at 6 months in 6.2, 12.9, and 13.8% of the patients who received TOR compared with the baseline. These decreases were maintained for at least 24 months. These lipid levels were not changed in those who received ANA. In the TOR patients, there was an increase in the serum level of HDL-C and Apo A1 at 6 months in 17.1 and 16.3%, respectively, which was maintained for at least 24 months, whereas these levels were almost stable in the patients who received ANA. Serum BAP decreased by 12.1% at 12 months and further decreased at 24 months and the serum NTX decreased by 22.0% at 6 months, which was maintained for at least 24 months in the patients who received TOR. In contrast, the serum BAP was increased by 26.0% at 6 months and by 29.2% at 12 months and the serum NTX increased by 21.3% at 24 months compared with baseline in those received ANA. However, the serum BAP increase was not significant at 24 months. TOR provides better effects than ANA in terms of lipid profiles and bone metabolism in postmenopausal females with early breast cancer.

Endometrial mullerian adenosarcoma after toremifene treatment in breast cancer patients: a case report

Toremifene is an anti-estrogen which has been shown to be effective in the treatment of breast cancer, and is thought to be a less uterotrophic agent than tamoxifen. The risk assessment concerning endometrial cancer has been inconclusive because of its rare use up to the mid-1990s. We report a case of an adenosarcoma, which is a very rare type of uterine malignancy, after toremifene treatment for 5 years in a breast cancer patient. After 1 year of toremifene use, the patient had a benign Mullerian adenofibroma. After an additional 4 years of toremifene treatment, the endometrial polypoid lesion was transformed into a Mullerian adenosarcoma. Although toremifene is a promising anti-estrogenic agent in the treatment of breast cancer patients, clinicians should not neglect the possibility of a uterine malignancy.

Selectively targeting estrogen receptors for cancer treatment

Estrogens regulate growth and development through the action of two distinct estrogen receptors (ERs), ERα and ERβ, which mediate proliferation and differentiation of cells. For decades, ERα mediated estrogen signaling has been therapeutically targeted to treat breast cancer, most notably with the selective estrogen receptor modulator (SERM) tamoxifen. Selectively targeting ERs occurs at two levels: tissue selectivity and receptor subtype selectivity. SERMs have been developed with emphasis on tissue selectivity to target ER signaling for breast cancer treatment. Additionally, new approaches to selectively target the action of ERα going beyond ligand-dependent activity are under current investigation. As evidence of the anti-proliferative role of ERβ accumulates, selectively targeting ERβ is an attractive approach for designing new cancer therapies with the emphasis shifted to designing ligands with subtype selectivity. This review will present the mechanistic and structural features of ERs that determine tissue and subtype selectivity with an emphasis on current approaches to selectively target ERα and ERβ for cancer treatment.

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.

Effects of toremifene and tamoxifen on lipid profiles in post-menopausal patients with early breast cancer: interim results from a Japanese phase III trial

OBJECTIVE

Toremifene and tamoxifen have been used for adjuvant therapy in post-menopausal patients with breast cancer in Japan. Dyslipidemias are common in post-menopausal women. However, limited data are available on the effects of these agents on lipid profiles in Japanese patients. The Japan Toremifene Cooperative Study Group has been conducting a Phase III randomized trial of post-menopausal patients with breast cancer. One of its secondary endpoints is to confirm the effects of these agents on serum lipid profiles.

METHODS

The subjects were post-menopausal Japanese patients who had undergone surgery for early breast cancer. Toremifene or tamoxifen was administered for 2 years. Lipid levels were measured before and up to 24 months after initiation.

RESULTS

Compared with baseline, at 24 months, the toremifene group (n = 123) showed significantly decreased total cholesterol (P < 0.001) and low-density lipoprotein cholesterol levels (P < 0.001), and significantly increased high-density lipoprotein cholesterol levels (P < 0.001). Their triglyceride levels were not affected (P = 0.677). The tamoxifen group (n = 120) also showed significantly decreased total cholesterol (P < 0.001) and low-density lipoprotein cholesterol levels (P < 0.001); no significant changes occurred in high-density lipoprotein cholesterol (P = 0.297) or triglyceride levels (P = 0.120).

CONCLUSIONS

Distinct differences between two selective estrogen receptor modulators on lipids were observed. Toremifene improved lipid profiles, particularly as an enhancer of high-density lipoprotein cholesterol. To a large extent, tamoxifen improved low-density lipoprotein cholesterol levels. The impact of these improved lipid profiles on the risk of cardiovascular diseases needs further confirmation.

Unbiased probing of the entire hepatitis C virus life cycle identifies clinical compounds that target multiple aspects of the infection

Over 170 million people are chronically infected by the hepatitis C virus (HCV) and at risk for dying from liver cirrhosis and hepatocellular carcinoma. Current therapy is expensive, associated with significant side effects, and often ineffective. Discovery of antiviral compounds against HCV traditionally involves a priori target identification followed by biochemical screening and confirmation in cell-based replicon assays. Typically, this results in the discovery of compounds that address a few predetermined targets and are prone to select for escape variants. To attempt to identify antiviral compounds with broad target specificity, we developed an unbiased cell-based screening system involving multiple rounds of infection in a 96-well format. Analysis of a publicly available library of 446 clinically approved drugs identified 33 compounds that targeted both known and previously unexplored aspects of HCV infection, including entry, replication, and assembly. Discovery of novel viral and cellular targets in this manner will broaden the therapeutic armamentarium against this virus, allowing for the development of drug mixtures that should reduce the likelihood of mutational escape.

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.

Second non-breast primary cancer following adjuvant therapy for early breast cancer: a report from the International Breast Cancer Study Group

The incidence of second non-breast primary cancer following adjuvant treatment was evaluated using data from patients enrolled from 1978 to 1999 in four International Breast Cancer Study Group (IBCSG) trials. The occurrence of these tumours as sites of the first failure was assessed separately for two treatment comparisons: toremifene versus tamoxifen for 5 years in 1035 patients in IBCSG Trials 12-93 and 14-93 with a median follow-up of 8 years and endocrine therapy (toremifene or tamoxifen) versus chemo-endocrine therapy (CMF or AC plus toremifene or tamoxifen) in 1731 patients from IBCSG Trials III, VII and 12-93, with a combined median follow-up of 14 years. No significant differences in second non-breast primary tumours were observed in either comparison. In particular, the incidences of second primary uterine tumours with toremifene and tamoxifen were similar and no significant increase of secondary leukaemias was observed with chemo-endocrine therapy compared with endocrine therapy.

Effect of combined therapy with the antiestrogen agent toremifene and local hyperthermia on breast cancer cells implanted in nude mice

PURPOSE

We evaluated the effects of combined treatment with the antiestrogen agent toremifene (TOR) and local hyperthermia (LHT) on the MCF-7 breast cancer cell line.

METHODS

BALB/c mice implanted with MCF-7 cells were divided into six treatment groups: a control group, a TOR30 group (given 30 mg/kg/day), a TOR120 group (given 120 mg/kg/day), an LHT group (43.5 degrees C), a TOR30 + LHT group, and a TOR120 + LHT group. The effects of the treatments on tumor cells, estrogen receptor (ER) expression, and cell cycle kinetics were measured after 21 days. We calculated the apoptotic index and vascular density inside the tumors and evaluated the efficacy of the transmigration of TOR into the tumors.

RESULTS

The antitumor effects were significantly greater in both combined therapy groups than in any of the single therapy groups. Estrogen receptor expression was weaker in the combined therapy groups than in the single therapy groups, and there were more G0/G1-phase cells and fewer S-phase cells in both combined therapy groups than in the single therapy groups. The apoptotic index was increased and the tumor vascular density was decreased in the combined therapy groups.

CONCLUSIONS

We attributed the effects of this combined therapy to the induction of apoptosis, the decrease in vascular density, and the increase and decrease in G0/G1-phase and S-phase cells, respectively, in the tumors.

Estrogen-mediated protection in myocardial ischemia-reperfusion injury

Before menopause, a woman has a relatively low risk for developing cardiovascular disease. After menopause, however, the risk increases nearly twofold and cardiovascular disease remains the number one cause of death among women. Observational trials and studies in animal models of cardiovascular disease suggested that females have reduced injury after myocardial ischemia and reperfusion injury. However, two large clinical trials, the women's health initiative (WHI) and the heart estrogen and progestin replacement study (HERS), found an increase in cardiovascular incidences in women taking hormone replacement therapy. The discrepancy between these data highlights the need for further research on the mechanism of estrogen in the cardiovascular system. Animal studies have demonstrated protective effects by endogenous estrogen (gender differences) and also by the administration of exogenous estrogen. In vivo studies suggest a possible anti-inflammatory mechanism of estrogen. Exogenous estrogen has been shown to have anti-oxidant activities. Pre-treatment with estrogen prior to myocardial ischemia and reperfusion causes a decrease in neutrophil infiltration into the irreversibly injured myocardium, decrease in C-reactive protein expression, and deposition of the membrane attack complex. This review will summarize the protection afforded by estrogen as well as discuss several possible mechanisms of protection for exogenous estrogen administration.

Selective estrogen receptor modulators: an update on recent clinical findings

Recent clinical data on selective estrogen receptor modulators (SERMs) have provided the basis for reassessment of the SERM concept. The molecular basis of SERM activity involves binding of the ligand SERM to the estrogen receptor (ER), causing conformational changes which facilitate interactions with coactivator or corepressor proteins, and subsequently initiate or suppress transcription of target genes. SERM activity is intrinsic to each ER ligand, which accomplishes its unique profile by specific interactions in the target cell, leading to tissue selective actions. We discuss the estrogenic and anti-estrogenic effects of early SERMs, such as clomiphene citrate, used for treatment of ovulation induction, and the triphenylethylene, tamoxifen, which has ER antagonist activity in the breast, and is used for prevention and treatment of ER-positive breast cancer. Since the development of tamoxifen, other triphenylethylene SERMs have been studied for breast cancer prevention, including droloxifene, idoxifene, toremifene, and ospemifene. Other SERMs have entered clinical development more recently, including benzothiophenes (raloxifene and arzoxifene), benzopyrans (ormeloxifene, levormeloxifene, and EM-800), lasofoxifene, pipendoxifene, bazedoxifene, HMR-3339, and fulvestrant, an anti-estrogen which is approved for breast cancer treatment. SERMs have effects on tissues containing ER, such as the breast, bone, uterine and genitourinary tissues, and brain, and on markers of cardiovascular risk. Current evidence indicates that each SERM has a unique array of clinical activities. Differences in the patterns of action of SERMs suggest that each clinical end point must be evaluated individually, and conclusions about any particular SERM can only be established through appropriate clinical trials.

Toremifene increases bone mineral density in men receiving androgen deprivation therapy for prostate cancer: interim analysis of a multicenter phase 3 clinical study

PURPOSE

We evaluated the effects of toremifene on bone mineral density, a surrogate for fracture risk, in men receiving androgen deprivation therapy for prostate cancer.

MATERIALS AND METHODS

In an ongoing, multicenter, phase 3 fracture prevention study 1,392 men 50 years or older with prostate cancer receiving androgen deprivation therapy were randomized to 80 mg toremifene per day or placebo. Bone mineral density of the lumbar spine, total hip and femoral neck was assessed using dual energy x-ray absorptiometry. In this planned interim analysis of the first 197 subjects we compared bone mineral density changes from baseline to month 12 between the placebo and toremifene groups.

RESULTS

Compared with the placebo group men in the toremifene group had significant increases in bone mineral density at each evaluated skeletal site. Lumbar spine bone mineral density decreased 0.7% in the placebo group and increased 1.6% in the toremifene group (between group comparison p <0.001). Total hip bone mineral density decreased 1.3% in the placebo group and increased 0.7% in the toremifene group (p = 0.001). Femoral neck bone mineral density decreased 1.3% in the placebo group and increased 0.2% in the toremifene group (p = 0.009). Between group differences in the change in bone mineral density from baseline to month 12 were 2.3%, 2.0% and 1.5% for the lumbar spine, total hip and femoral neck, respectively.

CONCLUSIONS

Toremifene significantly increased hip and spine bone mineral density in men receiving androgen deprivation therapy for prostate cancer. The effect of toremifene on the fracture risk is being assessed in the ongoing randomized, controlled trial.

Estrogen receptors: how do they signal and what are their targets

During the past decade there has been a substantial advance in our understanding of estrogen signaling both from a clinical as well as a preclinical perspective. Estrogen signaling is a balance between two opposing forces in the form of two distinct receptors (ER alpha and ER beta) and their splice variants. The prospect that these two pathways can be selectively stimulated or inhibited with subtype-selective drugs constitutes new and promising therapeutic opportunities in clinical areas as diverse as hormone replacement, autoimmune diseases, prostate and breast cancer, and depression. Molecular biological, biochemical, and structural studies have generated information which is invaluable for the development of more selective and effective ER ligands. We have also become aware that ERs do not function by themselves but require a number of coregulatory proteins whose cell-specific expression explains some of the distinct cellular actions of estrogen. Estrogen is an important morphogen, and many of its proliferative effects on the epithelial compartment of glands are mediated by growth factors secreted from the stromal compartment. Thus understanding the cross-talk between growth factor and estrogen signaling is essential for understanding both normal and malignant growth. In this review we focus on several of the interesting recent discoveries concerning estrogen receptors, on estrogen as a morphogen, and on the molecular mechanisms of anti-estrogen signaling.

Antiestrogens and the formation of DNA damage in rats: a comparison

Tamoxifen (TAM) has been used as an agent for the treatment and prevention of breast cancer. However, long-term treatment of TAM in women increases the risk of developing endometrial cancer. The secondary cancer may be due to the genotoxicity of TAM. To find safer alternatives, four selective estrogen receptor modulators (SERMs), 4-hydroxytamoxifen (4-OHTAM), toremifene (TOR), raloxifene (RAL), and ICI 182,780, were administered to rats with an equimolar dose of TAM [54 micromol/kg (20 mg/kg)/day, p.o. for 7 days]. To evaluate the genotoxicity of each SERM, the presence of bulky DNA adducts was determined by (32)P-postlabeling/polyacrylamide gel electrophoresis and (32)P-postlabeling/high-performance liquid chromatography. The formation of 7,8-dihydro-8-oxodeoxyguanosine (8-oxodG) was analyzed as a marker of typical oxidative damage, using liquid chromatography electrospray tandem mass spectrometry. Among the SERMs, bulky DNA adducts were detected in the livers of rats treated with TAM; the total amount of TAM-DNA adducts was 26.1 adducts/10(7) nucleotides. However, with a detection limit of approximately 2 adducts/10(9) nucleotides, no bulky DNA adducts were observed with 4-OHTAM, TOR, RAL, or ICI 182,780. In addition, no significant increase of hepatic 8-oxodG lesions was detected in rats treated with any of the antiestrogens. Therefore, TOR, RAL, and ICI 182,780 are likely to be less genotoxic than TAM.