Metabolism, distribution, and excretion of a next generation selective estrogen receptor modulator, lasofoxifene, in rats and monkeys

SERMs have substance-specific effects on bone, and these effects are mediated via ERαAF-1 in female mice

The bone-sparing effect of estrogens is mediated primarily via estrogen receptor (ER)α, which stimulates gene transcription through activation function (AF)-1 and AF-2. The role of ERαAF-1 for the estradiol (E2) effects is tissue specific. The selective ER modulators (SERMs) raloxifene (Ral), lasofoxifene (Las), and bazedoxifene (Bza) can be used to treat postmenopausal osteoporosis. They all reduce the risk for vertebral fractures, whereas Las and partly Bza, but not Ral, reduce the risk for nonvertebral fractures. Here, we have compared the tissue specificity of Ral, Las, and Bza and evaluated the role of ERαAF-1 for the effects of these SERMs, with an emphasis on bone parameters. We treated ovariectomized (OVX) wild-type (WT) mice and OVX mice lacking ERαAF-1 (ERαAF-1(0)) with E2, Ral, Las, or Bza. All three SERMs increased trabecular bone mass in the axial skeleton. In the appendicular skeleton, only Las increased the trabecular bone volume/tissue volume and trabecular number, whereas both Ral and Las increased the cortical bone thickness and strength. However, Ral also increased cortical porosity. The three SERMs had only a minor effect on uterine weight. Notably, all evaluated effects of these SERMs were absent in ovx ERαAF-1(0) mice. In conclusion, all SERMs had similar effects on axial bone mass. However, the SERMs had slightly different effects on the appendicular skeleton since only Las increased the trabecular bone mass and only Ral increased the cortical porosity. Importantly, all SERM effects require a functional ERαAF-1 in female mice. These results could lead to development of more specific treatments for osteoporosis.

Incorporating bazedoxifene into the treatment paradigm for postmenopausal osteoporosis in Japan

The incidence of osteoporosis-related fractures in Asian countries is steadily increasing. Optimizing osteoporosis treatment is especially important in Japan, where the rate of aging is increasing rapidlyelderly population is increasing rapidly and life expectancy is among the longest in the world. There are several therapies currently available in Japan for the treatment of postmenopausal osteoporosis, each with a unique risk/benefit profile. A novel selective estrogen receptor modulator, bazedoxifene (BZA), was recently approved for the treatment of postmenopausal osteoporosis in Japan. Results from a 2-year, phase 2 trial in postmenopausal Japanese women showed that BZA significantly improved lumbar spine and total hip bone mineral density compared with placebo, while maintaining endometrial and breast safety, consistent with results from 2 global, phase 3 trials including a 2-year osteoporosis prevention study and a 3-year osteoporosis treatment study. In the pivotal 3-year treatment study, BZA significantly reduced the incidence of new vertebral fractures compared with placebo; in a post hoc analysis of a subgroup of women at higher risk of fractures, BZA significantly reduced the risk of nonvertebral fractures compared with placebo and raloxifene. A 2-year extension of the 3-year treatment study demonstrated the sustained efficacy of BZA over 5 years of treatment. BZA was generally safe and well tolerated in these studies. In a "super-aging" society such as Japan, long-term treatment for postmenopausal osteoporosis is a considerable need. BZA may be considered as a first choice for younger women anticipating long-term treatment, and also an appropriate option for older women who are unable or unwilling to take bisphosphonates.

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.

Diabetes-ameliorating effects of fermented red ginseng and causal effects on hormonal interactions: testing the hypothesis by multiple group path analysis

Although diagnostic criteria for metabolic syndrome (MtS) vary among various health professionals and organizations, blood glucose dysregulation and insulin resistance are common to all definitions. Red ginseng is beneficial for glucose regulation and insulin sensitivity but the mechanism is not yet elucidated. Ginsenosides Rh1 and Rg3 act as ligands of the estrogen receptor, and Rh2 and compound K act as ligands of the glucocorticoid receptors, which may influence the diabetes markers. The objective of this study was to test the hypothesis that there are significant causal relationships among diabetes-related markers and several hormones, and assess whether or not the consumption of fermented red ginseng (FRG) influences these causal relationships by multiple group path analysis and conventional statistical analyses. The 93 postmenopausal women were randomly divided into two groups for a double-blind trial. FRG powder and placebo were provided for 2 weeks. The data were analyzed by multiple group path analysis and the mean between groups were compared. The model's goodness of fit was excellent, with a root mean square error of approximation of 0.00, and comparative fit index of 1.00. The FRG group exhibited significantly increased levels of dehydroepiandrosterone sulfate (DHEAS), growth hormone (GH), and estradiol (E2), and they exhibited decreased levels of glycosylated hemoglobin (HbA1c), insulin, and homeostatic model assessment of insulin resistance. With regard to the hypothesis, the blood glucose lowering effects of FRG were due to the negative effects of aldosterone and increased GH, which was associated with DHEAS and E2. Even though the differences of variables between both groups were small, the total effects of these variables may indicate beneficial changes for the prevention of diabetes in healthy postmenopausal women.

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.

A rapid and specific derivatization procedure to identify acyl-glucuronides by mass spectrometry

A simple procedure is described to identify acyl-glucuronides by coupled liquid chromatography/mass spectrometry after derivatization to a hydroxamic acid with hydroxylamine. The reaction specificity obviates the need for isolation of the acyl-glucuronide from an extract. Glucuronides derived from carbamic acids, and alkyl- and aromatic amines, are inert to the derivatization reaction conditions, making the hydroxamic acid derivative a fingerprint for acyl-glucuronides.