HMR 3339, a novel selective estrogen receptor modulator, reduces total cholesterol, low-density lipoprotein cholesterol, and homocysteine in healthy postmenopausal women

Impact of anti-oestrogen therapy on lipoprotein(a) in postmenopausal women: a systematic review and meta-analysis of double-blind placebo-controlled clinical studies

PURPOSE

The potential mechanisms of endocrine therapy for thrombosis remain currently unclear, and more studies are warranted for further investigation and elucidation. However, high plasma concentration of lipoprotein(a) (Lp(a)) is a recognized prothrombotic factor. The aim of our study was to systematically evaluate the effect of different anti-oestrogen therapy on plasma Lp(a) level in postmenopausal women.

METHODS

A systematic literature search was conducted in multiple electronic databases to identify the randomized, double-blind, placebo-controlled clinical studies on this topic. Effect size for changes in Lp(a) was expressed as mean difference (MD) and 95% confidence intervals (CI).

RESULTS

Data were pooled from 10 clinical trials comprising 24 treatment arms, which included 2049 women (1128 women in the active-treated arms and 921 women in the control arms). Meta-analysis of data suggested that anti-oestrogen therapy in women significantly reduced Lp(a) [MD = -5.92% (95%CI: -9.05%,-2.8%)].

CONCLUSIONS

This observation is of both clinical and pathophysiological relevance, also in view that the identification of molecular determinants and cellular pathways implicated in Lp(a) synthesis and metabolism is still of concern as a critical issue in lipidology and CV prevention.

Raloxifene Lowers Plasma Lipoprotein(a) Concentrations: a Systematic Review and Meta-analysis of Randomized Placebo-Controlled Trials

BACKGROUND AND AIMS

Lipoprotein(a) (Lp(a)) is a proatherogenic plasma lipoprotein and an independent risk factor for atherosclerotic cardiovascular disease. We investigated the effects of raloxifene, selective estrogen receptor modulator, on circulating Lp(a) levels in postmenopausal women using a systematic review and meta-analysis of randomized controlled trials (RCTs).

METHODS

To identify relevant studies, electronic databases (PUBMED, Scopus, Web of Science, and Google Scholar) were searched by up to May 2015 to find controlled trials exploring the effects of oral raloxifene treatment on plasma Lp(a) levels in postmenopausal women. A random-effects model and generic inverse variance method were used for quantitative data synthesis.

RESULTS

Overall, seven eligible RCTs with ten treatment arms were included in this meta-analysis. Meta-analysis suggested a significant reduction of Lp(a) levels after treatment with raloxifene (standardized mean difference (SMD) -0.42; 95% CI -0.65, -0.19; p < 0.001), which may be considered as a medium effect size. When the studies were categorized according to the administered dose, there was a significant effect in both subsets of studies with administered doses ≤60 mg/day (SMD -0.43; 95% CI -0.73, -0.13; p = 0.004) and >60 mg/day (SMD -0.36; 95% CI -0.68, -0.05; p = 0.025). No significant association between the changes in plasma concentrations of Lp(a) with dose and baseline Lp(a) levels was found in the random-effects meta-regression analysis. However, a significant inverse association was observed between the Lp(a)-lowering effect of raloxifene and duration of treatment (p = 0.001).

CONCLUSIONS

Results of the present meta-analysis showed a reduction in plasma Lp(a) concentrations of postmenopausal women with oral raloxifene treatment.

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.

Selective estrogen receptor modulators and risk for coronary heart disease

Coronary heart disease (CHD) is the leading cause of death in women in most countries. Atherosclerosis is the main biological process determining CHD. Clinical data support the notion that CHD is sensitive to estrogens, but debate exists concerning the effects of the hormone on atherosclerosis and its complications. Selective estrogen receptor modulators (SERMs) are compounds capable of binding the estrogen receptor to induce a functional profile distinct from estrogens. The possibility that SERMs may shift the estrogenic balance on cardiovascular risk towards a more beneficial profile has generated interest in recent years. There is considerable information on the effects of SERMs on distinct areas that are crucial in atherogenesis. The complexity derived from the diversity of variables affecting their mechanism of action plus the differences between compounds make it difficult to delineate one uniform trend for SERMs. The present picture, nonetheless, is one where SERMs seem less powerful than estrogens in atherosclerosis protection, but more gentle with advanced forms of the disease. The recent publication of the Raloxifene Use for The Heart (RUTH) study has confirmed a neutral effect for raloxifene. Prothrombotic states may favor occlusive thrombi at sites occupied by atheromatous plaques. Platelet activation has received attention as an important determinant of arterial thrombogenesis. Although still sparse, available evidence globally suggests neutral or beneficial effects for SERMs.

Effects on asymmetric dimethylarginine of HMR 3339, a novel selective estrogen receptor modulator

OBJECTIVE

To investigate the short-term effects of three different doses of the selective estrogen receptor modulator HMR 3339 in comparison with placebo and raloxifene on asymmetric dimethylarginine (ADMA), a nitric oxide synthase inhibitor.

DESIGN

This study was a multicenter, randomized, placebo-controlled, double-blind, dose-ranging study. Ninety-four healthy postmenopausal women received daily doses of either placebo (n=16), HMR 3339 2.5 mg (n=20), HMR 3339 10 mg (n=19), HMR 3339 50 mg (n=20), or raloxifene 60 mg (n=19) for 12 weeks. Fasting plasma concentrations of ADMA, arginine, and symmetric dimethylarginine (SDMA) were measured at baseline and after 4 and 12 weeks by high-performance liquid chromatography.

RESULTS

HMR 3339 induced a dose-dependent reduction of ADMA and SDMA concentrations, with the largest effects (P<0.01 for both) in the HMR 3339 50 mg group compared with baseline and placebo (at 12 weeks: -7.0% [95% CI, -14.2% to 0.2%] for ADMA and -16.2% [95% CI, -22.4% to -10.0%] for SDMA). Twelve weeks of raloxifene 60 mg significantly reduced SDMA (P=0.03) but not ADMA concentrations. Arginine concentrations were not altered by any treatment.

CONCLUSIONS

The reduction of the nitric oxide synthase inhibitor ADMA by HMR 3339 may potentially have a beneficial effect on the cardiovascular system in postmenopausal women.

The Cardiovascular Effects of Selective Estrogen Receptor Modulators

Coronary artery disease (CAD) is the main contributor of mortality among postmenopausal women. Menopause-associated estrogen deficiency has both metabolic and vascular consequences that increase the risk for CAD. Hormone therapy (HT) has been reported to have a beneficial effect on metabolic and vascular factors influencing the incidence of CAD. Although observational studies have reported that HT reduces significantly the risk for CAD, randomized clinical trials (WHI, HERS, ERA) have questioned the efficacy of HT in primary and secondary CAD prevention despite confirming the lipid-lowering effect of HT. In the aftermath of the WHI, increased interest has been given to the action of selective estrogen receptor modulators (SERMs) and their effect on the cardiovascular system. The chemical structure of SERMs, either triphenylethilyn (tamoxifen) or benzothiophene (raloxifene) derivatives, differs from that of estrogens. SERMs are nonsteroidal molecules that bind, with high affinity, to the ER. SERMs induce conformational changes to the ligand-binding domain of the ER that modulate the ability of the ER to interact with coregulator proteins. The relative balance of coregulators within a cell determines the transcriptional activity of the receptor-ligand complex. SERMs therefore may express an estrogen-agonist or estrogen-antagonist effect depending on the tissue targeted. SERMs express variable effects on the metabolic and vascular factors influencing the incidence of CAD. SERMs have been reported to modulate favorably the lipid-lipoprotein profile. Toremifene expresses the most beneficial effect followed by tamoxifene and raloxifene, while ospexifene and HMR-3339 have the least effect and may even increase triglycerides. Raloxifene and tamoxifene decrease serum homocysteine levels and C-reactive proteins (CRP), which are both markers of CAD risk. Raloxifene has been reported to increase the nitric oxide (NO)-endothelin (ET)-1 ratio and, thus, contribute to proper endothelial function and vasodilation. Toremifene has no effect on the NO-ET-1 ratio. Finally, raloxifene decreases the vascular cell adhesion molecules and the inflammatory cytokines TNF-alpha and IL-6. Of the SERMs, raloxifene has had the most extensive evaluation regarding the effect on the vascular wall of endothelium. Although not confirmed by large clinical trials, raloxifene has been reported to have an effect on the cohesion of the intercellular junction (VE-cadherin) and the synthesis-degradation of extracellular matrix (MMP-2). The Multiple Outcomes Raloxifene Evaluation (MORE) study has reported that raloxifene may have a cardioprotective effect when administered to postmenopausal women at high risk for CAD disease.

Emerging Selective Estrogen Receptor Modulators

Menopause, regardless of age at onset, is associated with a marked increase in coronary heart disease (CHD) risk. On the basis of epidemiological studies that demonstrated mainly positive effects of postmenopausal hormone therapy on CHD as well as on risk markers of CHD, it has been suggested that CHD could be prevented in postmenopausal women with long-term hormone therapy. However, since the publications of the Heart and Estrogen/progestin Replacement Study and the Women's Health Initiative trial, prescription of hormone therapy for the prevention of CHD has become controversial. Major efforts have been made to identify alternatives for hormone therapy. Compounds suggested have included selective estrogen receptor modulators (SERMs), which represent a class with a growing number of compounds that act as either estrogen receptor agonists or antagonists in a tissue-specific manner. This pharmacological profile may offer the opportunity to dissociate favourable estrogenic effects on the bone and cardiovascular system from unfavourable stimulatory effects on the breast and endometrium. Two SERMs presently on the market are tamoxifen and raloxifene. The only data available regarding the effects of tamoxifen on cardiovascular events in postmenopausal women are from breast cancer trials. These trials found fewer fatal myocardial events in women randomly assigned to tamoxifen compared with women assigned to placebo. Raloxifene is a second-generation SERM that has been shown to prevent osteoporotic fractures, is safe for the endometrium and holds high promise for the prevention of breast cancer. The effect of raloxifene on CHD is still uncertain. On the basis of the MORE (Multiple Outcomes of Raloxifene Evaluation) trial, raloxifene may offer some protection to women with CHD or to those who are at high risk of CHD. Proof that raloxifene reduces the risk of CHD requires a clinical trial with hard clinical endpoints. Such a study is currently underway. Next-generation SERMs taken into clinical development include idoxifene, droloxifene, ospemifene, arzoxifene, acolbifene/EM-800, levormeloxifene, lasofoxifene, bazedoxifene and HMR 3339. The aim is to find a compound with the ideal profile, that is, alleviation of climacteric symptoms and prevention of osteoporotic fractures, but without an adverse effect on the breast and endometrium, and no negative effect or even a beneficial effect on the cardiovascular system and the brain. Currently, limited data are available with regard to these next-generation SERMs and CHD. Nevertheless, some of these novel agents provide arguments for continuing the search for an ideal SERM.

The effects of 12 weeks of HMR 3339, a novel selective estrogen receptor modulator, on markers of coagulation and fibrinolysis: a randomized, placebo-controlled, double-blind, dose-ranging study in healthy postmenopausal women

OBJECTIVE

To investigate the short-term effects of HMR 3339, a novel selective estrogen receptor modulator, on markers of coagulation and fibrinolysis.

STUDY DESIGN

In a multicenter, 14-week, randomized, placebo-controlled, double-blind, dose-ranging study, healthy postmenopausal women received daily placebo (n = 22), HMR 3339 2.5 mg (n = 25), HMR 3339 10 mg (n = 24), HMR 3339 50 mg (n = 24), or raloxifene 60 mg (n = 23). Statistical analysis was performed using standard parametric tests.

RESULTS

After 12 weeks, compared with placebo, HMR 3339 50 mg induced the largest mean percentage changes in antithrombin (-14.6%, P < .001), protein C (-12.9%, P = .029), and fibrinogen (-26.3%, P = .001). Decreases were observed in the HMR 3339 2.5 mg group, compared with placebo, in tissue-type plasminogen activator (-55.0%, P = .026 after 4 weeks), plasmin-alpha2-antiplasmin complex (-85%, P = .031 and -63.3%, P = .008, respectively, after 4 and 12 weeks), and D-dimer (-91.4%, P = .018 after 12 weeks). Compared with placebo, raloxifene 60 mg decreased total protein S (-8.2%, P = .009) after 4 weeks and antithrombin (-6.0%, P = .034) and fibrinogen (-18.1%, P = .007) after 12 weeks.

CONCLUSION

HMR 3339 and raloxifene decreased fibrinogen levels. In the low dosage, HMR 3339 showed potentially beneficial effects on some markers of fibrinolysis. Both drugs impaired the anticoagulatory potential.