Neurokinin 3 receptor antagonists - prime time?

Global view of vasomotor symptoms and sleep disturbance in menopause: a systematic review

Studies have shown racial/ethnic differences in the prevalence of vasomotor symptoms (VMS), sleep disturbance and VMS treatment in menopause. To assess the reproducibility of these differences, we systematically reviewed observational studies, published in 2000-2021, reporting the prevalence/incidence of VMS, sleep disturbance or treatment use in menopausal women stratified by race/ethnicity. We screened 3799 records from PubMed and Embase and included 27 papers (19 studies). No incidence data were found. Prevalence data varied widely, but some common patterns emerged. In all five studies comparing VMS between Black women and White, Hispanic and/or East Asian women, the prevalence was highest in Black women and lowest in East Asian women. The prevalence of sleep disturbance overall was compared among Black, White and East Asian women in two study populations, and was highest in White women in both papers. Sleep disturbance was more common than VMS in East Asian women. In all four studies comparing hormone therapy use between White women and Black and/or East Asian women, treatment use was more common in White women. These results highlight the need for individualized counseling and treatment, outreach to under-served minorities, and standardized definitions and outcome measures for VMS and sleep disturbance for future studies.

Insights into the genetics of menopausal vasomotor symptoms: genome-wide analyses of routinely-collected primary care health records

BACKGROUND

Vasomotor symptoms (VMS) can often significantly impact women's quality of life at menopause. In vivo studies have shown that increased neurokinin B (NKB) / neurokinin 3 receptor (NK3R) signalling contributes to VMS, with previous genetic studies implicating the TACR3 gene locus that encodes NK3R. Large-scale genomic analyses offer the possibility of biological insights but few such studies have collected data on VMS, while proxy phenotypes such as hormone replacement therapy (HRT) use are likely to be affected by changes in clinical practice. We investigated the genetic basis of VMS by analysing routinely-collected health records.

METHODS

We performed a GWAS of VMS derived from linked primary-care records and cross-sectional self-reported HRT use in up to 153,152 women from UK Biobank, a population-based cohort. In a subset of this cohort (n = 39,356), we analysed exome-sequencing data to test the association with VMS of rare deleterious genetic variants. Finally, we used Mendelian randomisation analysis to investigate the reasons for HRT use over time.

RESULTS

Our GWAS of health-records derived VMS identified a genetic signal near TACR3 associated with a lower risk of VMS (OR=0.76 (95% CI 0.72,0.80) per A allele, P=3.7x10-27), which was consistent with previous studies, validating this approach. Conditional analyses demonstrated independence of genetic signals for puberty timing and VMS at the TACR3 locus, including a rare variant predicted to reduce functional NK3R levels that was associated with later menarche (P = 5 × 10-9) but showed no association with VMS (P = 0.6). Younger menopause age was causally-associated with greater HRT use before 2002 but not after.

CONCLUSIONS

We provide support for TACR3 in the genetic basis of VMS but unexpectedly find that rare genomic variants predicted to lower NK3R levels did not modify VMS, despite the proven efficacy of NK3R antagonists. Using genomics we demonstrate changes in genetic associations with HRT use over time, arising from a change in clinical practice since the early 2000s, which is likely to reflect a switch from preventing post-menopausal complications in women with earlier menopause to primarily treating VMS. Our study demonstrates that integrating routinely-collected primary care health records and genomic data offers great potential for exploring the genetic basis of symptoms.

Experience and severity of menopause symptoms and effects on health-seeking behaviours: a cross-sectional online survey of community dwelling adults in the United Kingdom

BACKGROUND

Almost all women will experience menopause, and the symptoms can have a severely detrimental impact on their quality of life. However, there is limited research exploring health-seeking behaviours and alternative service design or consultation formats. Group consultations have been successfully deployed in perinatal and diabetic care, improving accessibility and outcomes. This cross-sectional online survey was conducted to explore women's personal experiences of menopause, including perspectives on group consultations.

METHODS

An online survey investigated the experiences of individuals at all stages of menopause and their receptiveness towards group consultations for menopause. Respondents were categorised by menopause stage according to the STRAW + 10 staging system. Associations between menopause stage, acceptability of group consultations and participant demographics were assessed using logistic regression.

RESULTS

Respondents experienced an average of 10.7 menopausal symptoms, but only 47% of respondents felt they had the knowledge and tools to manage their symptoms. Advice on menopause was sought from a healthcare professional (HCP) by 61% of respondents, the largest trigger for this being severity of symptoms and the main barrier for this was the perception that menopause wasn't a valid enough reason to seek help. Of the respondents seeking advice from HCPs, 32% were prescribed transdermal HRT, 29% received oral HRT, 19% were offered antidepressants, 18% received local oestrogen and 6% were prescribed testosterone. Over three quarters (77%) of respondents indicated that they would join a group consultation for menopause and would be comfortable sharing their experiences with others (75%). Logistic regression indicated premenopausal respondents were 2.84 times more likely than postmenopausal women to be interested in a group consultation where they can meet or learn from others' experiences.

CONCLUSIONS

This study highlighted a strong willingness of women aged 35-70 to participate in group consultations for menopause, with motivation being strongest amongst premenopausal women. Low awareness of self-management and lifestyle interventions to manage the symptoms of menopause highlight the need for greater outreach, research and interventions to build knowledge and confidence in the general population at scale. Future studies should focus on investigating the effectiveness and economic impact of menopause group consultations and the lived experience of individuals participating in group consultations.

Neurokinin 1/3 receptor antagonists for menopausal women: A current systematic review and insights into the investigational non-hormonal therapy

BACKGROUND

Over 75% of menopausal women experience vasomotor symptoms (VMS), such as night sweats and hot flashes. Despite the prevalence of these symptoms, there is limited data on non-hormonal therapies to alleviate them.

METHODS

PubMed, Cochrane, Scopus, Ovid, Web of Science, and ClinicalTrials.Gov were searched for relevant studies. The search was performed using the following keywords, which were customized to suit the specific databases/registers: menopause, women, neurokinin 3, and/or Fezolinetant. The search was conducted until December 20, 2022. This systematic review was conducted in compliance with the PRISMA Statement 2020 guidelines.

RESULTS

A total of 326 records were found, with 10 studies (enrolling 1993 women) selected for inclusion. The women received 40-mg doses of NK1/3 receptor antagonists twice daily, with follow-ups at 1 to 3 weeks. Moderately strong evidence was found suggesting that NK1/3 receptor antagonists can help limit the frequency and severity of hot flashes in menopausal women.

CONCLUSION

While the results should be interpreted with caution until further clinical trials validate the efficacy and safety of NK1/3 receptor antagonists among menopausal women, these findings suggest that they are promising targets for future pharmacological and clinical studies in addressing vasomotor symptoms.

Management of menopause: a view towards prevention

Women spend approximately one-third of their lives with menopause, which occurs around 50 years of age. It is now appreciated that several important metabolic and cardiovascular disease risks emerge during the menopausal transition. Many important conditions occur 10-15 years after menopause, including weight gain and obesity, metabolic syndrome, diabetes, osteoporosis, arthritis, cardiovascular disease, dementia, and cancer; therefore, the occurrence of menopause heralds an important opportunity to institute preventative strategies. These strategies will lead to improved quality of life and decreased mortality. Various strategies are presented for treating symptoms of menopause and diseases that are asymptomatic. Among several strategies is the use of hormone therapy, which has efficacy for symptoms and osteoporosis, and can improve metabolic and cardiovascular health. When instituted early, which is key, in younger postmenopausal women (under 60 years) oestrogen has been found to consistently decrease mortality with a favourable risk-benefit profile in low-risk women. Prospective data show that long-term therapy might not be required for this benefit.

Functional Rescue of Inactivating Mutations of the Human Neurokinin 3 Receptor Using Pharmacological Chaperones

G protein-coupled receptors (GPCRs) facilitate the majority of signal transductions across cell membranes in humans, with numerous diseases attributed to inactivating GPCR mutations. Many of these mutations result in misfolding during nascent receptor synthesis in the endoplasmic reticulum (ER), resulting in intracellular retention and degradation. Pharmacological chaperones (PCs) are cell-permeant small molecules that can interact with misfolded receptors in the ER and stabilise/rescue their folding to promote ER exit and trafficking to the cell membrane. The neurokinin 3 receptor (NK3R) plays a pivotal role in the hypothalamic–pituitary–gonadal reproductive axis. We sought to determine whether NK3R missense mutations result in a loss of cell surface receptor expression and, if so, whether a cell-permeant small molecule NK3R antagonist could be repurposed as a PC to restore function to these mutants. Quantitation of cell surface expression levels of seven mutant NK3Rs identified in hypogonadal patients indicated that five had severely impaired cell surface expression. A small molecule NK3R antagonist, M8, increased cell surface expression in four of these five and resulted in post-translational receptor processing in a manner analogous to the wild type. Importantly, there was a significant improvement in receptor activation in response to neurokinin B (NKB) for all four receptors following their rescue with M8. This demonstrates that M8 may have potential for therapeutic development in the treatment of hypogonadal patients harbouring NK3R mutations. The repurposing of existing small molecule GPCR modulators as PCs represents a novel and therapeutically viable option for the treatment of disorders attributed to mutations in GPCRs that cause intracellular retention.

Neurokinin 3 Receptor Antagonists Compared With Serotonin Norepinephrine Reuptake Inhibitors for Non-Hormonal Treatment of Menopausal Hot Flushes: A Systematic Qualitative Review

Introduction

Hot flushes/flashes (HFs) or other vasomotor symptoms affect between 45 and 97% of women during menopause. Hormone replacement therapy (HRT) is effective at alleviating menopausal symptoms, but some women cannot or prefer not to take HRT. Since current non-hormonal options have suboptimal efficacy/tolerability, there is a pressing need for an effective, well-tolerated alternative. The neurokinin 3 receptor (NK3R) has recently been implicated in the generation of menopausal HFs and represents a novel therapeutic target to ameliorate HF symptoms. This review aims to assess if NK3R antagonists (NK3Ras) are more effective than Serotonin Norepinephrine Reuptake Inhibitors (SNRIs)—currently a common choice for non-hormonal treatment of menopausal HFs.

Methods

Studies were identified after systematically searching Ovid MEDLINE and EMBASE databases based on PRISMA guidelines. Trial quality and bias were assessed. Key efficacy outcomes (HF frequency, HF severity and number of night-time awakenings/night-sweats) and selected safety outcomes were extracted and analysed.

Results

Seven SNRI and four NK3Ra placebo-controlled randomised trials (plus four follow-up reports) were included in this review. NK3Ra administration resulted in a larger reduction from baseline in HF frequency, HF severity and night-sweats compared to SNRIs. Five of seven SNRI trials showed a reduction in HF frequency that was statistically significant (by 48–67% from baseline at weeks 8 or 12) whereas all NK3Ra trials showed a statistically significant reduction in HF frequency (by 62–93% from baseline at weeks 2, 4 or 12). While SNRI trials reported poor tolerability, particularly nausea, NK3Ra trials reported good tolerability overall, although two trials reported elevation in transaminases.

Conclusion

NK3Ras trials show encouraging efficacy and tolerability/safety. Completion of phase 3 NK3Ra trials are required to confirm efficacy and uphold safety/tolerability data but phase 2 results suggest that NK3Ras are more effective than SNRIs for non-hormonal treatment of menopausal HFs.