Effects of bazedoxifene in nonflushing postmenopausal women: a randomized phase 2 trial

Hormone therapy for sexual function in perimenopausal and postmenopausal women

BACKGROUND

The perimenopausal and postmenopausal periods are associated with many symptoms, including sexual complaints. This review is an update of a review first published in 2013.

OBJECTIVES

We aimed to assess the effect of hormone therapy on sexual function in perimenopausal and postmenopausal women.

SEARCH METHODS

On 19 December 2022 we searched the Gynaecology and Fertility Group Specialised Register, CENTRAL, MEDLINE, Embase, PsycINFO, CINAHL, LILACS, ISI Web of Science, two trials registries, and OpenGrey, together with reference checking and contact with experts in the field for any additional studies.

SELECTION CRITERIA

We included randomized controlled trials that compared hormone therapy to either placebo or no intervention (control) using any validated assessment tool to evaluate sexual function. We considered hormone therapy: estrogen alone; estrogen in combination with progestogens; synthetic steroids, for example, tibolone; selective estrogen receptor modulators (SERMs), for example, raloxifene, bazedoxifene; and SERMs in combination with estrogen.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures recommended by Cochrane. We analyzed data using mean differences (MDs) and standardized mean differences (SMDs). The primary outcome was the sexual function score. Secondary outcomes were the domains of sexual response: desire; arousal; lubrication; orgasm; satisfaction; and pain. We assessed the certainty of the evidence using the GRADE approach.

MAIN RESULTS

We included 36 studies (23,299 women; 12,225 intervention group; 11,074 control group), of which 35 evaluated postmenopausal women; only one study evaluated perimenopausal women. The 'symptomatic or early postmenopausal women' subgroup included 10 studies, which included women experiencing menopausal symptoms (symptoms such as hot flushes, night sweats, sleep disturbance, vaginal atrophy, and dyspareunia) or early postmenopausal women (within five years after menopause). The 'unselected postmenopausal women' subgroup included 26 studies, which included women regardless of menopausal symptoms and women whose last menstrual period was more than five years earlier. No study included only women with sexual dysfunction and only seven studies evaluated sexual function as a primary outcome. We deemed 20 studies at high risk of bias, two studies at low risk, and the other 14 studies at unclear risk of bias. Nineteen studies received commercial funding. Estrogen alone versus control probably slightly improves the sexual function composite score in symptomatic or early postmenopausal women (SMD 0.50, 95% confidence interval (CI) (0.04 to 0.96; I² = 88%; 3 studies, 699 women; moderate-quality evidence), and probably makes little or no difference to the sexual function composite score in unselected postmenopausal women (SMD 0.64, 95% CI -0.12 to 1.41; I² = 94%; 6 studies, 608 women; moderate-quality evidence). The pooled result suggests that estrogen alone versus placebo or no intervention probably slightly improves sexual function composite score (SMD 0.60, 95% CI 0.16 to 1.04; I² = 92%; 9 studies, 1307 women, moderate-quality evidence). We are uncertain of the effect of estrogen combined with progestogens versus placebo or no intervention on the sexual function composite score in unselected postmenopausal women (MD 0.08 95% CI -1.52 to 1.68; 1 study, 104 women; very low-quality evidence). We are uncertain of the effect of synthetic steroids versus control on the sexual function composite score in symptomatic or early postmenopausal women (SMD 1.32, 95% CI 1.18 to 1.47; 1 study, 883 women; very low-quality evidence) and of their effect in unselected postmenopausal women (SMD 0.46, 95% CI 0.07 to 0.85; 1 study, 105 women; very low-quality evidence). We are uncertain of the effect of SERMs versus control on the sexual function composite score in symptomatic or early postmenopausal women (MD -1.00, 95% CI -2.00 to -0.00; 1 study, 215 women; very low-quality evidence) and of their effect in unselected postmenopausal women (MD 2.24, 95% 1.37 to 3.11 2 studies, 1525 women, I² = 1%, low-quality evidence). We are uncertain of the effect of SERMs combined with estrogen versus control on the sexual function composite score in symptomatic or early postmenopausal women (SMD 0.22, 95% CI 0.00 to 0.43; 1 study, 542 women; very low-quality evidence) and of their effect in unselected postmenopausal women (SMD 2.79, 95% CI 2.41 to 3.18; 1 study, 272 women; very low-quality evidence). The observed heterogeneity in many analyses may be caused by variations in the interventions and doses used, and by different tools used for assessment.

AUTHORS' CONCLUSIONS

Hormone therapy treatment with estrogen alone probably slightly improves the sexual function composite score in women with menopausal symptoms or in early postmenopause (within five years of amenorrhoea), and in unselected postmenopausal women, especially in the lubrication, pain, and satisfaction domains. We are uncertain whether estrogen combined with progestogens improves the sexual function composite score in unselected postmenopausal women. Evidence regarding other hormone therapies (synthetic steroids and SERMs) is of very low quality and we are uncertain of their effect on sexual function. The current evidence does not suggest the beneficial effects of synthetic steroids (for example tibolone) or SERMs alone or combined with estrogen on sexual function. More studies that evaluate the effect of estrogen combined with progestogens, synthetic steroids, SERMs, and SERMs combined with estrogen would improve the quality of the evidence for the effect of these treatments on sexual function in perimenopausal and postmenopausal women.

Effects of Bazedoxifene/Vitamin D Combination Therapy on Serum Vitamin D Levels and Bone Turnover Markers in Postmenopausal Women with Osteopenia: A Randomized Controlled Trial

BACKGROUND

This study aimed to evaluate the effectiveness of bazedoxifene/vitamin D combination therapy in preventing osteoporosis in postmenopausal women with osteopenia.

METHODS

This was an open-label, multicenter randomized-controlled, phase 4 clinical trial. Women between ages of 55 and 70 years in 9 medical tertiary centers in Korea were enrolled and assigned into 2 groups: an experiment group and a control group. The experimental group received bazedoxifene 20 mg/vitamin D 800 IU tablets for 6 months, and the control group received calcium 100 mg/vitamin D 1,000 IU tablets for 6 months.

RESULTS

A total of 142 patients (70 in the experimental group and 72 in the control group) were included. The least-square mean±standard error of change in propeptide of type I collagen after 3 months was -6.87±2.56% in the experimental group and 1.22±2.54% in the control group. After 6 months, it was -21.07±2.75% in the experimental group and 1.26±2.71% in the control group. The difference between the 2 groups was -22.33% (p<0.01). The change of C-terminal telopeptide was -12.55±4.05% in the experimental group and 11.02±4.03% in the control group after 3 months. It was -22.0±3.95% and 10.20±3.89, respectively, after 6 months. The difference between the 2 groups was -32.21% (p<0.01) after 6 months. There was no significant difference in adverse events between the 2 groups.

CONCLUSIONS

The osteoporosis preventive effect and safety of administering bazedoxifene/vitamin D combination pill were confirmed in postmenopausal women who needed osteoporosis prevention.

Bioequivalence for a Fixed-Dose Combination Formulation of Bazedoxifene and Cholecalciferol Compared With the Corresponding Single Entities Given Together

A fixed-dose combination (FDC) formulation of bazedoxifene 20 mg and cholecalciferol 8 mg was developed to increase medication compliance and convenience for osteoporosis patients. This study was conducted to demonstrate bioequivalence by comparing the pharmacokinetic (PK) profiles and tolerability of an FDC tablet and the individual component tablets. A randomized, open-label, single-dosing, 2-treatment, 2-period, 2-sequence crossover study was conducted in 52 healthy subjects. All subjects were randomly assigned to 2 sequences, and they received FDC tablets of bazedoxifene and cholecalciferol and individual component tablets. Serial blood samples for PK evaluation were collected up to 24 hours predose and 120 hours postdose, and the PK parameters were estimated by noncompartmental methods. Throughout the study, tolerability was assessed based on adverse events, vital signs, and clinical laboratory tests. Of the enrolled 52 subjects, 47 subjects completed the study. The results, the geometric mean ratios (GMRs) and 90% confidence intervals (90%CIs), of bazedoxifene C_max and AUC_0-t for FDC to single entities given together were 0.98 (0.91-1.05) and 1.02 (0.97-1.07), respectively. The GMRs (90%CIs) of cholecalciferol C_max and AUC_0-t for FDC to single entities given together were 0.96 (0.91-1.00) and 0.94 (0.90-0.99), respectively. Overall, the GMRs (90%CIs) of the PK parameter of bazedoxifene and cholecalciferol fell within the conventional bioequivalence range of 0.8-1.25. There were no clinically significant differences in the safety profile between the 2 treatments. In conclusion, this study confirmed the development of a new FDC drug by demonstrating that the FDC formulation of bazedoxifene and cholecalciferol is biologically equivalent to the coadministered individual formulations.

Pharmacokinetic comparison of two bazedoxifene acetate 20 mg tablet formulations in healthy Korean male volunteers

Bazedoxifene, used as bazedoxifene acetate, is a selective estrogen receptor modulator that selectively affects the uterus, breast tissue, bone metabolism, and lipid metabolism by antagonizing or enhancing estrogens in the estrogen receptor in the tissue. This study was conducted as an open, randomized, two-period, two-treatment, crossover design to compare the pharmacokinetic (PK) characteristics and tolerability of two bazedoxifene tablets when administered to 50 healthy Korean male volunteers. Enrolled subjects were randomly allocated to 2 sequences of a single oral administration of a test drug and a reference drug, or vice versa with a 14-day washout period between the two doses. Serial blood samples were collected over 96 h for PK analysis. Plasma concentration of bazedoxifene was assayed using liquid chromatography-tandem spectrometry mass. Forty-five participants completed the study with no clinically relevant safety issues. The peak concentrations (C_max, mean ± strandard deviation) of reference drug and test drug were 3.191 ± 1.080 and 3.231 ± 1.346 ng/mL, respectively, and the areas under the plasma concentration‐time curve from 0 to the last measurable concentration (AUC_last) were 44.697 ± 21.168 ng∙h/mL and 45.902 ± 23.130 ng∙h/mL, respectively. The geometric mean ratios of test drug to reference drug and their 90% confidence intervals for C_max and AUC_last were 0.9913 (0.8828–1.1132) and 1.0106 (0.9345–1.0929), respectively. The incidence of adverse events between the two formulations was similar. The present study showed that PK and tolerability of two bazedoxifene tablet formulations were comparable when administered to healthy Korean male volunteers.

Variation in menopausal vasomotor symptoms outcomes in clinical trials: a systematic review

BACKGROUND

There is substantial variation in how menopausal vasomotor symptoms are reported and measured among intervention studies. This has prevented meaningful comparisons between treatments and limited data synthesis.

OBJECTIVES

To review systematically the outcome reporting and measures used to assess menopausal vasomotor symptoms from randomised controlled trials of treatments.

SEARCH STRATEGY

We searched MEDLINE, Embase, and Cochrane Central Register of Controlled Trials from inception to May 2018.

SELECTION CRITERIA

Randomised controlled trials with a primary outcome of menopausal vasomotor symptoms in women and a sample size of at least 20 women per study arm.

DATA COLLECTION AND ANALYSIS

Data about study characteristics, primary vasomotor-related outcomes and methods of measuring them.

MAIN RESULTS

The search identified 5591 studies, 214 of which were included. Forty-nine different primary reported outcomes were identified for vasomotor symptoms and 16 different tools had been used to measure these outcomes. The most commonly reported outcomes were frequency (97/214), severity (116/214), and intensity (28/114) of vasomotor symptoms or a composite of these outcomes (68/214). There was little consistency in how the frequency and severity/intensity of vasomotor symptoms were defined.

CONCLUSIONS

There is substantial variation in how menopausal vasomotor symptoms have been reported and measured in treatment trials. Future studies should include standardised outcome measures which reflect the priorities of patients, clinicians, and researchers. This is most effectively achieved through the development of a Core Outcome Set. This systematic review is the first step towards development of a Core Outcome Set for menopausal vasomotor symptoms.

TWEETABLE SUMMARY

Menopausal hot flushes and night sweats have been reported in 49 different ways in clinical research. A core outcome set is urgently required.

Bazedoxifene for the treatment of osteoporosis

Introduction: Bazedoxifene (BZD) is a third-generation selective estrogen receptor modulator approved for the treatment of postmenopausal osteoporosis with additional favorable effects in lipids, uterine and breast tissue. Areas covered: In this review, the authors outline clinical data regarding the efficacy, safety, and tolerability of continuous BZD administration up to seven years in randomized, placebo-controlled, phase III clinical trials. Long-term treatment with BZD for postmenopausal osteoporosis is generally safe and well tolerated. BZD achieves small but significant increases in the bone mineral density of the lumbar spine but not the total hip. In addition, BZD reduces significantly the risk of vertebral fractures but not of non-vertebral and hip fractures, with the exception of high fracture risk postmenopausal women in whom BZD significantly reduces non-vertebral fractures. Expert opinion: BZD does not seem to offer significant advantages over the other available antiresorptive agents. However, considering the need for long-term management of osteoporosis, BZD may have a place in the long-term therapeutic planning of the disease.

Pharmacokinetics, Dose Proportionality, and Bioavailability of Bazedoxifene in Healthy Postmenopausal Women

PURPOSE

Bazedoxifene is a selective estrogen receptor modulator that has estrogen agonist effects on bone and lipid metabolism while having neutral or estrogen antagonist effects on the breast and endometrium. The present report describes findings from 3 Phase I clinical studies that evaluated the single-dose pharmacokinetics (study 1; n = 84), multiple-dose pharmacokinetics (study 2; n = 23), and absolute bioavailability (study 3; n = 18) of bazedoxifene.

METHODS

All 3 studies enrolled healthy postmenopausal women who were either naturally postmenopausal or had undergone bilateral oophorectomy at least 6 months before the start of the study.

FINDINGS

Study 1 showed that unconjugated and total (unconjugated and conjugated) bazedoxifene levels increased proportionally with ascending oral doses of bazedoxifene (through the dose range of 5-120 mg). Evaluation with or without food intake was conducted at the 10-mg dose, with no clinically relevant effect on pharmacokinetic parameters. Study 2 showed that bazedoxifene achieved steady state in 1 week and exhibited linear pharmacokinetics in doses of 5 to 40 mg with no unexpected accumulation over the dose range. In accordance with a linear pharmacokinetic profile, mean maximum plasma concentration values increased with increasing dose, with values of 1.6, 6.2, and 12.5 ng/mL for the 5-, 20-, and 40-mg doses, respectively. In study 3, tablet and capsule formulations of bazedoxifene formulations had an estimated oral bioavailability of ~6%. The clearance of bazedoxifene was 0.4 (0.1) L/h/kg based on intravenous administration. The oral formulations had comparable exposure profiles with respect to AUC and AUC0-t, and the 90% CIs for these values were within the bioequivalence limits of 80% to 125%. Bazedoxifene was safe and well tolerated in all 3 studies.

IMPLICATIONS

These pharmacokinetic evaluations in healthy postmenopausal women found that bazedoxifene displayed linear pharmacokinetics with doses ranging from 5 to 40 mg, with no unexpected accumulation. Food did not seem to have any clinically relevant impact on pharmacokinetic parameters. Bazedoxifene had an estimated oral bioavailability of ~6% and was safe and well tolerated in the range of doses evaluated.

The Tissue-Selective Estrogen Complex: A Review of Current Evidence

The tissue-selective estrogen complex (TSEC) has recently entered the market for the treatment of postmenopausal osteoporosis, and is particularly targeted to women with significant vasomotor symptoms. This review appraises the evidence behind the only approved TSEC to-date, a combination of bazedoxifene and conjugated estrogens, with regards to its efficacy and relevant safety concerns. The majority of evidence that has led to its approval is derived from the SMART study. This large phase III trial with several substudies was aimed at discerning the effects of the TSEC on various estrogen-responsive tissues in comparison to raloxifene and placebo. Overall, the evidence thus far suggests a superior improvement in lumbar bone mineral density of 1.01% ± 0.28% as well as decrease in the frequency of hot flushes. Regarding safety concerns, endometrial thickness did not change over the treatment course, and investigators also identified a modest reduction in breast density. While there was no difference in rates of venous thromboembolism between treatment and placebo groups in a 2-year follow-up period, the effects of the drug on coagulation profiles are similar to those seen with hormone replacement therapy. Thus, the drug's effects on venous thromboembolism risk over a longer treatment course remain unclear. In conclusion, the actual efficacy of the TSEC for postmenopausal osteoporosis remains as yet undefined, given the lack of fracture prevention data. The evidence thus far does seem to suggest a beneficial effect on vasomotor symptoms and a generally favorable side effect profile. However, it should be noted that only one study has addressed this question thus far, and so the repeatability of the findings is still in question.

Profile of bazedoxifene/conjugated estrogens for the treatment of estrogen deficiency symptoms and osteoporosis in women at risk of fracture

Decreasing levels of estrogens during menopause are associated with reduced bone density and an increased risk of osteoporosis. Many women also experience bothersome vasomotor and vaginal symptoms during the menopausal transition. Results of systematic reviews and meta-analyses of randomized controlled trials have shown that both systemic estrogen therapy or hormone therapy (estrogen combined with a progestin) are useful to prevent bone loss, and they are the most effective treatment for such climacteric symptoms as hot flushes, sweating, vaginal dryness, and dyspareunia. Unfortunately, estrogen therapy and hormone therapy increase the risk of endometrial and breast cancer, respectively. The selective estrogen receptor modulators (SERMs) result in positive estrogenic effects on bone, with no negative effects on the endometrium and breast but do not provide relief from postmenopausal symptoms. The combination of a SERM with estrogen as a tissue selective estrogen complex (TSEC) is a new strategy for the prevention of bone loss and the treatment of climacteric symptoms. This combination is particularly interesting from a clinical point of view, taking into account that estrogen alone did not increase breast cancer risk by the Women’s Health Initiative. TSEC is hypothesized to provide the benefits of estrogen-alone therapy, with an improved tolerability profile because the SERM component can make possible the elimination of progestin. The objective of this review was to critically evaluate the evidence from the reports published to date on the use of bazedoxifene (a third-generation SERM) in combination with conjugated estrogens in postmenopausal women. The conclusion is that effectively, the combination of bazedoxifene and conjugated estrogens may be a promising alternative to hormone therapy for the prevention of osteoporosis and the treatment of postmenopausal symptoms in non-hysterectomized postmenopausal women.

Hormone therapy for sexual function in perimenopausal and postmenopausal women

BACKGROUND

The perimenopausal and postmenopausal periods are associated with many symptoms, including sexual complaints.

OBJECTIVES

To assess the effect of hormone therapy (HT) on sexual function in perimenopausal and postmenopausal women.

SEARCH METHODS

We searched for articles in the Cochrane Menstrual Disorders and Subfertility Group (MDSG) Specialised Register, CENTRAL, MEDLINE, EMBASE, CINAHL, PsycINFO, LILACS, ClinicalTrials.gov, Current Controlled Trials, WHO International Clinical Trials Registry Platform, ISI Web of Knowledge and OpenGrey. The last search was performed in December 2012.

SELECTION CRITERIA

We included randomised controlled trials comparing HT to either placebo or no intervention (control). We considered as HT estrogens alone; estrogens in combination with progestogens; synthetic steroids (for example tibolone); or selective estrogen receptor modulators (SERMs) (for example raloxifene, bazedoxifene). Studies of other drugs possibly used in the relief of menopausal symptoms were excluded. We included studies that evaluated sexual function using any validated assessment tool. The primary outcome was a composite score for sexual function and the scores for individual domains (arousal and sexual interest, orgasm, and pain) were secondary outcomes. Studies were selected by two authors independently.

DATA COLLECTION AND ANALYSIS

Data were independently extracted by two authors and checked by a third. Risk of bias assessment was performed independently by two authors. We contacted study investigators as required. Data were analysed using standardized mean difference (SMD) and relative risk (RR). We stratified the analysis by participant characteristics with regard to menopausal symptoms. The overall quality of the evidence for the primary outcome was evaluated using the GRADE criteria.

MAIN RESULTS

The search retrieved 2351 records from which 27 studies (16,393 women) were included. The 'symptomatic or early post-menopausal' subgroup included nine studies: perimenopausal women (one study), up to 36 months postmenopause (one study), up to five years postmenopause (one study), experiencing vasomotor or other menopausal symptoms (five studies), or experiencing hot flushes and sexual dysfunction (one study). The 'unselected postmenopausal women' subgroup included 18 studies, which included women regardless of menopausal symptoms and permitted the inclusion of women with more than five years since the final menstrual period. No studies were restricted to women with sexual dysfunction. Only five studies evaluated sexual function as a primary outcome. Eighteen studies were deemed at high risk of bias, and the other nine studies were at unclear risk of bias. Twenty studies received commercial funding.Findings for sexual function (measured by composite score):For estrogens alone versus control, in symptomatic or early postmenopausal women the SMD and 95% CI were compatible with a small to moderate benefit in sexual function for the HT group (SMD 0.38, 95% CI 0.23 to 0.54, P < 0.00001, 3 studies, 699 women, I² = 55%, high-quality evidence). In unselected postmenopausal women, the 95% CI was compatible with no effect to a small benefit (SMD 0.16, 95% CI -0.02 to 0.34, P = 0.08, 2 studies, 478 women, I² = 44%, low-quality evidence). The subgroups were not pooled because of considerable heterogeneity.For estrogens combined with progestogens versus control, in symptomatic or early postmenopausal women the 95% CI was compatible with a small to moderate benefit for sexual function in the HT group (SMD 0.42, 95% CI 0.19 to 0.64, P = 0.0003, 1 study, 335 women, moderate-quality evidence). In unselected postmenopausal women, the 95% CI was compatible with no effect to a small benefit (SMD 0.09, 95% CI -0.02 to 0.20, P = 0.10, 3 studies, 1314 women, I² = 0%, moderate-quality evidence). The subgroups were not pooled because of considerable heterogeneity.For tibolone versus control, in symptomatic or early postmenopausal women the 95% CI was compatible with no effect to a small benefit for sexual function in the HT group (SMD 0.13, 95% CI 0.00 to 0.26, P = 0.05, 1 study, 883 women, low-quality evidence). In unselected postmenopausal women, the 95% CI was compatible with no effect to a moderate benefit (SMD 0.38, 95% CI 0.04 to 0.71, P = 0.03, 2 studies, 142 women, I² = 0%, low-quality evidence). In the combined analysis, the 95% CI was compatible with no effect to a small benefit (SMD 0.17, 95% CI 0.04 to 0.29, P = 0.008, 3 studies, 1025 women, I² = 20%).For SERMs versus control, in symptomatic or early postmenopausal women the 95% CI was compatible with no effect to a moderate benefit for sexual function in the HT group (SMD 0.23, 95% CI -0.04 to 0.50, P = 0.09, 1 study, 215 women, low-quality evidence). In unselected postmenopausal women, the 95% CI was compatible with small harm to a small benefit (SMD 0.04, 95% CI -0.20 to 0.29, P = 0.72, 1 study, 283 women, low-quality evidence). In the combined analysis, the 95% CI was compatible with no effect to a small benefit (SMD 0.13, 95% CI -0.05 to 0.31, P = 0.16, 2 studies, 498 women, I² = 2%).A comparison of SERMs combined with estrogens versus control was only evaluated in symptomatic or early postmenopausal women. The 95% CI was compatible with no effect to a small benefit for sexual function in the HT group (SMD 0.21, 95% CI 0.00 to 0.43, P = 0.05, 1 study, 542 women, moderate-quality evidence).

AUTHORS' CONCLUSIONS

HT treatment with estrogens alone or in combination with progestogens was associated with a small to moderate improvement in sexual function, particularly in pain, when used in women with menopausal symptoms or in early postmenopause (within five years of amenorrhoea), but not in unselected postmenopausal women. Evidence regarding other HTs (synthetic steroids and SERMs) is of low quality and we are uncertain of their effect on sexual function. The current evidence does not suggest an important effect of tibolone or of SERMs alone or combined with estrogens on sexual function. More studies evaluating the effect of synthetic steroids, SERMS and the association of SERM + estrogens would improve the quality of the evidence for the effect of these treatments on sexual function in peri and postmenopausal women. Future studies should also evaluate the effect of HT solely among women with sexual complaints.

Nuclear receptors and their selective pharmacologic modulators

Nuclear receptors are ligand-activated transcription factors and include the receptors for steroid hormones, lipophilic vitamins, sterols, and bile acids. These receptors serve as targets for development of myriad drugs that target a range of disorders. Classically defined ligands that bind to the ligand-binding domain of nuclear receptors, whether they are endogenous or synthetic, either activate receptor activity (agonists) or block activation (antagonists) and due to the ability to alter activity of the receptors are often termed receptor "modulators." The complex pharmacology of nuclear receptors has provided a class of ligands distinct from these simple modulators where ligands display agonist/partial agonist/antagonist function in a tissue or gene selective manner. This class of ligands is defined as selective modulators. Here, we review the development and pharmacology of a range of selective nuclear receptor modulators.