Preclinical characterization of zuranolone (SAGE-217), a selective neuroactive steroid GABAA receptor positive allosteric modulator

Effect of two novel GABAA receptor positive allosteric modulators on neuropathic and inflammatory pain in mice

Loss of GABAergic inhibition in the spinal dorsal horn (SDH) is implicated in central sensitization and chronic pain. Both agonists and positive allosteric modulators (PAMs) of GABAA receptor are found to be effective in the management of chronic pain. In addition to benzodiazepines, neuroactive steroids (NASs) also act as PAMs through binding to unique sites of GABAA receptors. Thus, it is worth investigating whether these NASs can attenuate chronic pain. This study tested the antinociceptive properties of two novel NAS PAMs, ganaxolone and zuranolone, in segmental spinal nerve ligation (SNL)-induced neuropathic pain and complete Freund's adjuvant (CFA)-induced inflammation pain models. Spinally administered ganaxolone and zuranolone both exhibited dose-dependent analgesic effects but with quite different durations. This antinociceptive effect might be generated from elevated GABAergic inhibition, as the PAMs both enhanced GABA-evoked currents in SDH neurons, and the K+-Cl- cotransporter isoform 2 (KCC2) antagonist reversed the analgesic effect of the PAMs. Different from ganaxolone, zuranolone produced a durable increase in the surface expression of GABAA receptors and of the amplitude of spontaneous inhibitory currents, which may contribute to the long-lasting analgesic effect. Furthermore, the PAMs alleviated SNL-induced mechanical allodynia synergistically with diazepam or GABAA receptor activator muscimol at inactive doses, consistent with the non-competitive activity and distinct binding sites from benzodiazepines. In summary, our findings suggest that NASs may not only acutely modulate GABA receptor activity but also induce sustained metabotropic effects on GABAA receptors and thus exert long-lasting antinociceptive effects.

Synthesis and Evaluation of a Novel Zuranolone Analog with High GABAA Receptor PAM Activity and Excellent Pharmacokinetic Profiles

Zuranolone (SAGE-217), the first FDA-approved oral neurosteroid (NAS), a positive allosteric modulator (PAM) of γ-aminobutyric acid type A (GABAA) receptor for postpartum depression approved in 2023, has limitations such as short half-life, low bioavailability, and central inhibitory side effects. To address these, we designed novel C-21 modified derivatives of Zuranolone, identifying the triazolone scaffold as key for enhancing GABAA activity. Here, we synthesized Zuranolone analogs with diverse triazolone substituents, finding that pyridine-derived modifications improved the activity correlated with LogP. The optimal derivative, S9 (2-(trifluoroethoxy)pyridine-triazolone, LogP 4.61), showed 2.5-fold greater potency (EC50) and efficacy (Emax) than Zuranolone (LogP 4.78) at synaptic/extrasynaptic GABAA receptors, attributed to stronger binding via molecular docking. In rats, S9 exhibited 5-fold longer plasma T1/2, 6-fold higher AUC, 3-fold greater brain exposure, and 30% improved bioavailability. It also outperformed Zuranolone in pentylenetetrazole (PTZ)-induced seizure suppression and threshold dose for loss of righting reflex (LORR) in rats. The C21-pyridine-triazolone pharmacophore in S9 enhances receptor activity potency without increasing lipophilicity, optimizing pharmacokinetics and safety, which makes it a promising therapeutic candidate for depression and epilepsy.

The translocator protein 18 kDa (TSPO) ligand etifoxine in an animal model of anxiety: Line- and sex-dependent effects on emotionality, stress reactivity, spine density, oxytocin receptors, steroids, and microbiome composition

The treatment of stress-related disorders such as anxiety and depression is still challenging. One potential therapeutical option are neurosteroids. Their synthesis is promoted by ligands of the mitochondrial translocator protein 18 kDa (TSPO). We tested the TSPO ligand etifoxine (ETX) in a rat model of hyper-anxiety and depression-like behavior, i.e., in female and male HAB (high anxiety-related behavior) rats, as well as in respective low anxiety (LAB) and non-selected control (NAB) rats for behavioral, molecular, cellular, and physiological parameters. Daily acute i.p. treatment with ETX or vehicle over 5 or 9 days revealed that ETX was most effective in female HAB rats; it reduced anxiety levels (5 days) and OXT-R binding brain site-specifically (5 and 9 days), and increased spine density (5 days). The behavioral ETX effect exclusively found in female HABs was accompanied by increased 3β5α-THDOC levels, without any effect in female LABs and NABs and on other neurosteroids. In males of all breeding lines, ETX changed a total of 10 out of 23 brain steroids. Passive stress-coping during 10-min forced swimming was not affected by 9-day treatment with ETX, the resulting stress-induced plasma corticosterone levels were higher in ETX-treated NAB rats of both sexes compared with their VEH-treated groups. The fecal bacterial composition was similar but beta diversity differed between HABs and LABs and from NABs independent of sex; ETX treatment had no effect. Therefore, we propose considering the aspect of sex in treatment strategies for anxiety disorders. This is particularly important to establish better treatment regimens for women.

Unlocking NAC's potential ATF4 and m6A dynamics in rescuing cognitive impairments in PTSD

In this study, we investigated the therapeutic potential of N-acetylcysteine (NAC) in a mouse model of post-traumatic stress disorder (PTSD) induced by a single prolonged stress (SPS) protocol. Our findings demonstrate that NAC treatment significantly improved cognitive function and mitigated hippocampal neuronal apoptosis in PTSD model mice. These positive effects were accompanied by a reduction in m6A methylation levels and activating transcription factor 4 (ATF4) expression. Silencing ATF4 further attenuated hippocampal neuronal apoptosis and cognitive dysfunction, while ATF4 overexpression partially reversed the beneficial effects of NAC. It suggests that NAC's efficacy in PTSD may be mediated by its regulation of ATF4 expression and m6A methylation levels. Overall, our study provides valuable insights into the potential mechanism of action for NAC in PTSD treatment, offering promising avenues for future therapeutic strategies.

Emerging Medications for Treatment-Resistant Depression: A Review with Perspective on Mechanisms and Challenges

Background/Objectives: Non-response to initial treatment options for major depressive disorder (MDD) is a common clinical challenge with profound deleterious impacts for affected patients. Few treatments have received regulatory approval for treatment-resistant depression (TRD). Methods: A systematic search of United States and European Union clinical trials registries was conducted to identify Phase II, III, or IV clinical trials, with a last update posted on or after 1 January 2020, that were evaluating medications for TRD. For both the US and EU registries, the condition term "treatment resistant depression" and associated lower-level terms (per registry search protocol) were used. For the US registry, a secondary search using the condition term "depressive disorders" and the modifying term "inadequate" was also performed to capture registrations not tagged as TRD. Two additional searches were also conducted in the US registry for the terms "suicide" and "anhedonia" as transdiagnostic targets of investigational medications. Trials were categorized based on the primary mechanism of action of the trial's investigational medication. Results: Fifty clinical trials for TRD, 20 for anhedonia, and 25 for suicide were identified. Glutamate system modulation was the mechanism currently with the most compounds in development, including antagonists and allosteric modulators of NMDA receptors, AMPA receptors, metabotropic type 2/3 glutamate receptors, and intracellular effector molecules downstream of glutamate signaling. Psychedelics have seen the greatest surge among mechanistic targets in the past 5 years, however, with psilocybin in particular garnering significant attention. Other mechanisms included GABA modulators, monoamine modulators, anti-inflammatory/immune-modulating agents, and an orexin type 2 receptor antagonist. Conclusions: These investigations offer substantial promise for more efficacious and potentially personalized medication approaches for TRD. Challenges for detecting efficacy in TRD include the heterogeneity within the TRD population stemming from the presumed variety of biological dysfunctions underlying the disorder, comorbid disorders, chronic psychosocial stressors, and enduring effects of prior serotonergic antidepressant medication treatments.

Abnormal choroid plexus, hippocampus, and lateral ventricles volumes as markers of treatment-resistant major depressive disorder

AIM

One-third of patients with major depressive disorder (MDD) do not achieve full remission and have high relapse rates even after treatment, leading to increased medical costs and reduced quality of life and health status. The possible specificity of treatment-resistant depression (TRD) neurobiology is still under investigation, with risk factors such as higher inflammatory markers being identified. Given recent findings on the role of choroid plexus (ChP) in neuroinflammation and hippocampus in treatment response, the aim of the present study was to evaluate inflammatory- and trophic-related differences in these regions along with ventricular volumes among patients with treatment-sensitive depression (TSD), TRD, and healthy controls (HCs).

METHODS

ChP, hippocampal, and ventricular volumes were assessed in 197 patients with MDD and 58 age- and sex-matched HCs. Volumes were estimated using FreeSurfer 7.2. Treatment resistance status was defined as failure to respond to at least two separate antidepressant treatments. Region of interest volumes were then compared among groups.

RESULTS

We found higher ChP volumes in patients with TRD compared with patients with TSD and HCs. Our results also showed lower hippocampal volumes and higher lateral ventricular volumes in TRD compared with both patients without TRD and HCs.

CONCLUSIONS

These findings corroborate the link between TRD and neuroinflammation, as ChP volume could be considered a putative marker of central immune activity. The lack of significant differences in all of the region of interest volumes between patients with TSD and HCs may highlight the specificity of these features to TRD, possibly providing new insights into the specific neurobiological underpinnings of this condition.

Nitrogen-containing heterocyclic drug products approved by the FDA in 2023: Synthesis and biological activity

This article profiles 13 newly approved nitrogen-containing heterocyclic drugs by the U.S. Food and Drug Administration (FDA) in 2023. These drugs target a variety of therapeutic areas including proteinuria in patients with IgA nephropathy, migraine in adults, Rett syndrome, PI3Kδ syndrome, vasomotor symptoms, alopecia areata, acute myeloid leukemia, postpartum depression, myelofibrosis, and various cancer and tumor types. The molecular structures of these approved drugs feature common aromatic heterocyclic compounds such as pyrrole, imidazole, pyrazole, isoxazole, pyridine, and pyrimidine, as well as aliphatic heterocyclic compounds like caprolactam, piperazine, and piperidine. Some compounds also contain multiple heteroatoms like 1,2,4-thiadiazole and 1,2,4-triazole. The article provides a comprehensive overview of the bioactivity spectrum, medicinal chemistry discovery, and synthetic methods for each compound.

Cognitive effects, pharmacokinetics, and safety of zuranolone administered alone or with alprazolam or ethanol in healthy adults in a phase 1 trial

BACKGROUND

Zuranolone is an oral, once-daily, 14-day treatment course approved for adults with postpartum depression in the United States.

AIMS

To assess cognitive effects, pharmacokinetics, and safety of zuranolone, alone or with alprazolam/ethanol.

METHODS

This was a phase 1, two-part, two-period, randomized, double-blind, placebo-controlled crossover trial. Participants received zuranolone 50 mg or placebo once daily for 9 days, and additionally received alprazolam (1 mg, Part A), ethanol (males: 0.7 g/kg; females: 0.6 g/kg, Part B), or corresponding placebo on days 1, 5, and 9. Within each part, participants received all treatment combinations. Cognition was assessed using a computerized test battery; pharmacokinetics and safety were also evaluated.

RESULTS

All participants (Part A, N = 24; Part B, N = 25) received ⩾1 dose of zuranolone/placebo. Compared to placebo, zuranolone produced small-to-moderate cognitive decline (Cohen's |d| = 0.126-0.76); effects were larger with alprazolam (Cohen's |d| = 0.523-0.93) and ethanol (Cohen's |d| = 0.345-0.88). Zuranolone coadministration with alprazolam (Cohen's |d| = 0.6-1.227) or ethanol (Cohen's |d| = 0.054-0.5) generally worsened cognitive decline when compared with zuranolone alone. Maximal pharmacodynamic effects occurred at approximately 5 h and were resolved by 12 h postbaseline. No pharmacokinetic interactions were observed. Incidence of adverse events was similar between groups; most events were mild or moderate in severity.

CONCLUSION

A general small-to-moderate magnitude decline in cognition occurred with zuranolone alone. Coadministration with alprazolam/ethanol increased the magnitude, but not the duration, of effects compared with single-agent administration. Zuranolone prescribers and patients should be aware of the potential for increased central nervous system-depressant effects if coadministered with GABAergic active compounds such as alprazolam and ethanol.

Targeting the PI3K/AKT signaling pathway with PNU120596 protects against LPS-induced acute lung injury

OBJECTIVES

This study investigated the potential therapeutic benefits of PNU120596, a positive allosteric modulator of the α7 nicotinic acetylcholine receptor (α7nAChR), in mitigating acute lung injury (ALI) induced by lipopolysaccharide (LPS) in a mouse model. Specifically, we sought to examine the impact of PNU120596 on the PI3K/AKT signaling pathway in the context of ALI.

METHODS

ALI was induced in mice by LPS administration, and the protective effects of PNU120596 were assessed. Lung injury, lung function, and the inflammatory response were evaluated. Additionally, the activation of the PI3K/AKT signaling pathway was examined, along with the levels of inflammatory factors and oxidative stress markers.

KEY FINDINGS

PNU120596 significantly ameliorated LPS-induced lung injury, improved lung function, and reduced the inflammatory response in the mouse model of ALI. Furthermore, we observed that PNU120596 inhibited the activation of the PI3K/AKT signaling pathway, which was associated with decreased levels of inflammatory factors and oxidative stress markers.

CONCLUSIONS

PNU120596 exhibits promising therapeutic potential for the treatment of acute lung injury, potentially by targeting the PI3K/AKT signaling pathway. These findings suggest that modulation of the α7 nicotinic acetylcholine receptor with PNU120596 may offer a viable strategy for the management of ALI, warranting further investigation and potential clinical applications.

Current Developments in the Treatment of Postpartum Depression: Zuranolone

Pregnancy is a period in a woman's life during which she experiences physiological, psychological, and social changes. These changes can lead to various mental illnesses, including postpartum depression (PPD), which is common during the perinatal period. Postpartum depression is a significant cause of morbidity and mortality for both the mother and baby. A peripartum-onset major depressive episode is defined as PPD when it occurs during pregnancy or up to 4 weeks postpartum. The frequency of this condition is extremely high. Its etiology is influenced by biological, psychological, and sociocultural factors. Depressed mood, anhedonia, feelings of guilt, irritability, lack of concentration, psychomotor agitation or retardation, sleep disturbance, and changes in appetite and weight can all be symptoms of PPD. There are various treatment options available, many of which are adapted from those used for major depression. Selective serotonin reuptake inhibitors, serotonin-noradrenaline reuptake inhibitors, tricyclic antidepressants, estradiol, progesterone, psychotherapies, electroconvulsive therapy, and brexanolone can be used to treat PPD. In addition, the newest drug approved by the FDA (Food and Drug Administration) for this condition is oral zuranolone. This review aims to analyze recent developments on zuranolone, the latest drug approved by the FDA for PPD, based on current studies.

Zuranolone for the Treatment of Postpartum Depression

Objective

To review the safety, efficacy, and tolerability of zuranolone for the treatment of postpartum depression.

Data Sources

A literature search was conducted through PubMed using the following terms: zuranolone, postpartum depression, perinatal depression, SAGE-217, and allopregnanolone analogue.

Study Selection and Data Extraction

Articles describing the pharmacology, pharmacokinetics, efficacy, safety, and/or tolerability of zuranolone were included in this review.

Data Synthesis

Zuranolone is an allopregnanolone analogue that works through modulation of the GABAA receptor. Clinical trials have demonstrated that compared with placebo, zuranolone is effective in treating patients with postpartum depression. Common adverse events associated with zuranolone include fatigue, somnolence, headache, dizziness, diarrhea, sedation, upper respiratory tract infection, and nausea.

Conclusions

Pharmacotherapeutic options to treat postpartum depression include selective serotonin reuptake inhibitors or serotonin-norepinephrine reuptake inhibitors, with the medication brexanolone (the first allopregnanolone analogue) reserved for severe postpartum depression. Zuranolone, the newest medication in its class, is without the same limitations as brexanolone, thus affording providers an additional easy-to-use option for treating postpartum depression.

Synthesis and evaluation of neuroactive steroids with novel pharmacophore at C-21 let identify a compound with advantageous PK profile and higher EC50 and Emax as PAM on GABAA receptor

Zuranolone (SAGE-217) is a neuroactive steroid (γ-aminobutyric acid)A (GABAA) receptor positive allosteric modulator (PAM) as the first oral drug approved by the FDA in 2023, which is used to treat patients with postpartum depression (PPD). SAGE-217 has a "black box" warning with impairing ability to drive or engage in other potentially hazardous activities. In addition, SAGE-217 can cause CNS depressant effects such as somnolence and confusion, suicidal thoughts and behavior and embryo-fetal toxicity. Based on the structure-activity relationship (SAR) of SAGE-217, a total of 28 neuroactive steroids with novel pharmacophore at C-21 modulated SAGE-217 derivatives were designed and synthesized. The biological activities were evaluated by both synaptic α1β2γ2 GABAA receptor and extrasynaptic α4β3δ GABAA receptor cell assays. The optimal compound S28 exhibited much more potent potency and similar efficacy at extrasynaptic GABAA receptor than SAGE-217. Different from above, compound S28 exhibited similar potency and lower efficacy at synaptic GABAA receptor than SAGE-217, which were consistent with the analysis of molecular docking and dynamics simulation results. The appropriate lower efficacy at synaptic GABAA receptor of compound S28 might contribute to reduce the side effects of excessive sedation. Furthermore, compound S28 was demonstrated to have excellent in vivo pharmacokinetic (PK) parameters, robust in vivo pharmacodynamic (PD) effects and good safety profiles. Therefore, compound S28 represents a potentially promising treatment of PPD candidate that warrants further investigation.

A comprehensive review of small molecule drugs approved by the FDA in 2023: Advances and prospects

In 2023, the U.S. Food and Drug Administration has approved 55 novel medications, consisting of 17 biologics license applications and 38 new molecular entities. Although the biologics license applications including antibody and enzyme replacement therapy set a historical record, the new molecular entities comprising small molecule drugs, diagnostic agent, RNA interference therapy and biomacromolecular peptide still account for over 50 % of the newly approved medications. The novel and privileged scaffolds derived from drugs, active molecules and natural products are consistently associated with the discovery of new mechanisms, the expansion of clinical indications and the reduction of side effects. Moreover, the structural modifications based on the promising scaffolds can provide the clinical candidates with the improved biological activities, bypass the patent protection and greatly shorten the period of new drug discovery. Therefore, conducting an appraisal of drug approval experience and related information will expedite the identification of more potent drug molecules. In this review, we comprehensively summarized the pertinent information encompassing the clinical application, mechanism, elegant design and development processes of 28 small molecule drugs, and expected to provide the promising structural basis and design inspiration for pharmaceutical chemists.

The emergence of antidepressant drugs targeting GABAA receptors: A concise review

Depression is among the most common psychiatric illnesses, which imposes a major socioeconomic burden on patients, caregivers, and the public health system. Treatment with classical antidepressants (e.g. tricyclic antidepressants and selective serotonine reuptake inhibitors), which primarily affect monoaminergic systems has several limitations, such as delayed onset of action and moderate efficacy in a relatively large proportion of depressed patients. Furthermore, depression is highly heterogeneus, and its different subtypes, including post-partum depression, involve distinct neurobiology, warranting a differential approach to pharmacotherapy. Given these shortcomings, the need for novel antidepressants that are superior in efficacy and faster in onset of action is fully justified. The development and market introduction of rapid-acting antidepressants has accelerated in recent years. Some of these new antidepressants act through the GABAergic system. In this review, we discuss the discovery, efficacy, and limitations of treatment with classic antidepressants. We provide a detailed discussion of GABAergic neurotransmission, with a special focus on GABAA receptors, and possible explanations for the mood-enhancing effects of GABAergic medications (in particular neurosteroids acting at GABAA receptors), and, ultimately, we present the most promising molecules belonging to this family which are currently used in clinical practice or are in late phases of clinical development.

Protection from oxygen-glucose deprivation by neurosteroid treatment in primary neurons and oligodendrocytes

Preterm birth results in an increased risk of neonatal brain injury and neurobehavioural disorders. Despite the seriousness of these adverse outcomes, there are currently no effective therapies to protect the vulnerable developing brain. We propose that neurosteroid replacement therapy may be a novel approach in reducing detrimental neurological outcomes following preterm birth. The use of guinea pig primary neuronal and oligodendrocyte cultures with relevance to late gestation allows insight into the mechanisms behind the effectiveness of these treatments. Primary neuronal and oligodendrocyte cultures were derived from fetal guinea pig frontal cortex brain tissue at gestational age 62 (GA62). Cell cultures were pre-treated with either etifoxine (5 µM) or zuranolone (1 µm) for 24 h prior to insult. Cells were then exposed to either oxygen-glucose deprivation (OGD; 0% O2 and no glucose DMEM; preterm birth insult) or sham (standard cell culture conditions; 25 mM DMEM) for 2 h. Lactate dehydrogenase assay (LDH) was performed following OGD as a measure of cytotoxicity. Relative mRNA expression of key neuronal and oligodendrocyte markers, as well as neuronal receptors and transporters, were quantified using high throughput (Fluidigm) RT-PCR. OGD significantly increased cellular cytotoxicity in both neurons and oligodendrocytes. Additionally, key neuronal marker mRNA expression was reduced following OGD, and oligodendrocytes displayed arrested mRNA expression of key markers of lineage progression. Treatment with etifoxine restored a number of parameters back to control levels, whereas treatment with zuranolone provided a robust improvement in all parameters examined. This study has demonstrated the neuroprotective potential of neurosteroid replacement therapy in a model of hypoxia related to preterm birth. Neuroprotection appears to be mediated through glutamate reduction and increased brain derived neurotrophic factor (BDNF). Future work is warranted in examining these treatments in vivo, with the overall aim to suppress preterm associated brain damage and reduce long term outcomes for affected offspring.

Pediatric suicide: Review of a preventable tragedy

Concepts of suicide are explored in this issue with a focus on suicide in children and adolescents. The epidemiology of pediatric suicide in the United States is reviewed; also, risk and protective factors, as well as prevention strategies, are discussed. Suicide in the pediatric athlete and the potential protective effect of exercise are examined. In addition, this analysis addresses the beneficial role of psychological management as well as current research on pharmacologic treatment and brain stimulation procedures as part of comprehensive pediatric suicide prevention. Though death by suicide in pediatric persons has been and remains a tragic phenomenon, there is much that clinicians, other healthcare professionals, and society itself can accomplish in the prevention of pediatric suicide as well as the management of suicidality in our children and adolescents.

Neurosteroids and translocator protein 18 kDa (TSPO) ligands as novel treatment options in depression

Recently, the gamma-aminobutyric acid (GABA) system has come into focus for the treatment of anxiety, postpartum depression, and major depressive disorder. Endogenous 3α-reduced steroids such as allopregnanolone are potent positive allosteric modulators of GABAA receptors and have been known for decades. Current industry developments and first approvals by the U.S. food and drug administration (FDA) for the treatment of postpartum depression with exogenous analogues of these steroids represent a major step forward in the field. 3α-reduced steroids target both synaptic and extrasynaptic GABAA receptors, unlike benzodiazepines, which bind to synaptic receptors. The first FDA-approved 3α-reduced steroid for postpartum depression is brexanolone, an intravenous formulation of allopregnanolone. It has been shown to provide rapid relief of depressive symptoms. An orally available 3α-reduced steroid is zuranolone, which also received FDA approval in 2023 for the treatment of postpartum depression. Although a number of studies have been conducted, the efficacy data were not sufficient to achieve approval of zuranolone in major depressive disorder by the FDA in 2023. The most prominent side effects of these 3α-reduced steroids are somnolence, dizziness and headache. In addition to the issue of efficacy, it should be noted that current data limit the use of these compounds to two weeks. An alternative to exogenous 3α-reduced steroids may be the use of substances that induce endogenous neurosteroidogenesis, such as the translocator protein 18 kDa (TSPO) ligand etifoxine. TSPO has been extensively studied for its role in steroidogenesis, in addition to other functions such as anti-inflammatory and neuroregenerative properties. Currently, etifoxine is the only clinically available TSPO ligand in France for the treatment of anxiety disorders. Studies are underway to evaluate its antidepressant potential. Hopefully, neurosteroid research will lead to the development of fast-acting antidepressants.

Evaluating the safety and efficacy of zuranolone in the management of major depressive disorder and postpartum depression, with or without concurrent insomnia: a rigorous systematic review and meta-analysis

Introduction

Major depressive disorder (MDD), postpartum depression (PPD), and insomnia are neuropsychological conditions in which zuranolone is used to improve symptoms and prognosis of the disorder. This meta-analysis aimed to determine the efficacy of zuranolone in comparison to other drugs used for treating these conditions.

Methods

This meta-analysis included patients aged between 18 and 75 years who were diagnosed with major depressive disorder and postpartum depression with or without insomnia and were administered zuranolone for treatment. Only randomized controlled trials (RCTs) were included, and animal studies were excluded. The databases used were PubMed, Scopus, Cochrane, and Clinicaltrials.gov, with MeSH terms and relevant keywords for (Zuranolone) and (Depression). The Cochrane risk of bias tool was used for quality assessment.

Results

The meta-analysis included eight RCTs that analyzed data from 2031 patients. The meta-analysis revealed statistically significant changes in the Hamilton Depression Rating Scale (HAM-D), Montgomery-Åsberg Depression Rating Scale (MADRS), Hamilton Anxiety Rating Scale (HAM-A), and treatment-emergent adverse effects (TEAE) scores in the PPD subgroup. HAM-D and TEAEs scores were also significant in the MDD subgroup, but the changes in the MADRS, HAM-A, and Bech-6 scores were insignificant. Serious adverse events were insignificant in all subgroups.

Conclusion

Meta-analysis found a significant improvement in depressive symptoms with zuranolone treatment, especially on day 15. This suggests that zuranolone is a promising therapeutic option for patients with MDD and PPD with or without insomnia.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=459554, identifier CRD42023459554.

Zuranolone Concentrations in the Breast Milk of Healthy, Lactating Individuals: Results From a Phase 1 Open-Label Study

PURPOSE/BACKGROUND

Zuranolone is a positive allosteric modulator of both synaptic and extrasynaptic γ-aminobutyric acid type A receptors and a neuroactive steroid approved as an oral, once-daily, 14-day treatment course for adults with postpartum depression in the United States. This study assessed zuranolone transfer into breast milk.

METHODS/PROCEDURES

Healthy, nonpregnant, lactating adult female participants received once-daily 30 mg zuranolone from day (D)1 through D5 in this phase 1 open-label study. The relative infant dose (RID; weight-adjusted proportion of the maternal dose in breast milk over 24 hours) for 30 mg zuranolone was assessed at D5. An RID for 50 mg zuranolone was estimated using a simulation approach across a range of infant ages and weights.

FINDINGS/RESULTS

Of 15 enrolled participants (mean age, 30.1 years), 14 completed the study. The mean RID for 30 mg zuranolone at D5 was 0.357%; the mean steady-state milk volume over D3 to D5 decreased from baseline by 8.3%. Overall unbound zuranolone in plasma was low (≤0.49%). Plasma concentrations peaked at D5 before decreasing in a biexponential manner. There was strong concordance between the temporal profiles of zuranolone concentrations in plasma and breast milk. The estimated mean RID for 50 mg zuranolone based on a milk intake of 200 mL/kg per day was 0.984%. All treatment-emergent adverse events reported by participants were mild, the most common being dizziness (n = 3).

IMPLICATIONS/CONCLUSIONS

Zuranolone transfer into the breast milk of healthy, nonpregnant, lactating adult female participants was low; the estimated RID for 50 mg zuranolone was <1%, well below the <10% threshold generally considered compatible with breastfeeding.

The efficacy and safety of Zuranolone for treatment of depression: A systematic review and meta-analysis

RATIONALE

Zuranolone, a newly FDA-approved synthetic neurosteroid, shows promise in treating depression.

OBJECTIVES

Our aim is to evaluate Zuranolone's efficacy and safety in treating depression.

METHODS

Five databases were searched until September 2023 for relevant randomized clinical trials evaluating the efficacy and safety of zuranolone. The potential risk of bias in the included trials was evaluated by the Cochrane Risk of Bias II guideline Data were extracted and pooled using Review Manager Software (RevMan 5.3).

RESULTS

An analysis of eight studies highlights Zuranolone's efficacy in treating depression compared to placebo across most of the outcomes. Notably, the 30mg and 50mg doses demonstrated significant improvements in reducing HAM-D scores by over 50% within a 15-day follow-up (RR) of 1.46 (95% CI [1.27, 1.68], p < 0.0001) and 1.14 (95% CI [1.01, 1.3], p = 0.04). Additionally, the HAM-D ≤ 7% score analysis revealed significant enhancements with the 30mg dose over both 15-day (RR = 1.82, 95% CI [1.44, 2.31], p < 0.0001) and 45-day (RR = 1.43, 95% CI [1.16, 1.77], p = 0.0008) durations. Adverse Events Drug Discontinuation demonstrated no overall significant difference (OR = 1.33, 95% CI: [0.79, 2.23], p = 0.282). Further, specific adverse events, such as headache, showed no significant overall difference between Zuranolone and placebo (OR = 1.11, 95% CI: [0.84, 1.47], p = 0.47), with dose-dependent analysis revealing less headache in the 30 mg group.

CONCLUSION

Zuranolone demonstrates favorable tolerability and safety, particularly at 30mg and 50mg doses after 15 days, suggesting its potential and effective treatment for depression.

The Emerging Role of Neurosteroids: Novel Drugs Brexanalone, Sepranolone, Zuranolone, and Ganaxolone in Mood and Neurological Disorders

This review investigates the potential of neurosteroids, including brexanolone, zuranolone, sepranolone, and ganaxalone, as therapeutic agents for a range of mood and neurological disorders. Notably, these disorders encompass postpartum depression, post-traumatic stress disorder (PTSD), major depressive disorder (MDD), epilepsy, and Alzheimer's disease. Brexanolone and zuranolone have emerged as frontrunners in the treatment of postpartum depression, offering rapid relief from debilitating symptoms. Their mechanism of action involves modulation of the gamma-aminobutyric acid (GABA) system, which plays a pivotal role in mood regulation. Clinical trials have demonstrated their efficacy, heralding a potential breakthrough in addressing this often-overlooked condition. In the context of PTSD and MDD, neurosteroids have demonstrated significant promise. Their positive allosteric modulation of GABA-A receptors translates into improved mood stabilization and reduced symptoms. This novel approach represents a departure from conventional treatments and could offer newfound hope for individuals grappling with these disorders. Beyond mood disorders, neurosteroids, especially ganaxalone, exhibit potential in the realm of epilepsy management. Ganaxalone's capacity to control seizures is attributed to its GABAergic activity, which helps restore the delicate balance of neurotransmission in epileptic brains. Moreover, neurosteroids have revealed neuroprotective properties in Alzheimer's disease models. By influencing the GABAergic system, they mitigate excitotoxicity, a hallmark of Alzheimer's pathology. This neuroprotection opens a novel avenue for slowing neurodegeneration, although further research and clinical validation are essential. In conclusion, this review underscores the substantial therapeutic promise of neurosteroids in mood and neurological disorders. Their modulation of the GABA system emerges as a central mechanism of action, emphasizing the importance of GABAergic signaling in these conditions. The path forward entails continued investigation and clinical trials to fully unlock the potential of neurosteroids, offering hope for enhanced treatments in these challenging clinical domains.

Zuranolone: The First FDA-Approved Oral Treatment Option for Postpartum Depression

OBJECTIVE

The objective of this study was to review the characteristics, efficacy, and safety of zuranolone in the management of postpartum depression (PPD).

DATA SOURCES

Literature was identified using PubMed (1966-August 2023) and EMBASE (1973-August 2023) and clinicaltrials.gov. Search terms included zuranolone, SAGE-217, and PPD with further limitation of those published in English.

STUDY SELECTION AND DATA EXTRACTION

Articles selected for inclusion included trials evaluating zuranolone for the treatment of PPD.

DATA SYNTHESIS

Zuranolone was evaluated for the treatment of moderate to severe PPD in 2 phase III trials. Both studies resulted in statistically significant improvement in depressive symptoms at day 15 (P = 0.003 and P < 0.001). Sustained differences in remission rates favoring zuranolone were found in both studies at day 45 compared with placebo (P = 0.01 and P < 0.05). Zuranolone was well tolerated, with somnolence, dizziness, headache, and sedation reported as the most common side effects.

RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE IN COMPARISON TO EXISTING DRUGS

Zuranolone is only the second medication approved by the Food and Drug Administration (FDA) for PPD and offers an advantage over brexanolone in that it can administered orally in the outpatient setting. The rapid onset of effect of zuranolone is advantageous to traditional antidepressant therapy which can be weeks to months; however, limited information is available on safety during lactation.

CONCLUSIONS

The recent FDA approval of oral zuranolone for PPD offers a second rapid-acting treatment for PPD, extending the opportunity for treatment to patients in the outpatient setting.

Different dosage regimens of zuranolone in the treatment of major depressive disorder: A meta-analysis of randomized controlled trials

OBJECTIVE

To investigate the efficacy and safety of different dosage regimens of zuranolone in the treatment of patients with major depressive disorder (MDD).

METHODS

PubMed, Embase, The Cochrane Library and other databases were searched from inception until July 2019. Randomized controlled trials (RCTs) related to the efficacy and safety of zuranolone in the treatment of MDD were included. The data were extracted independently by 2 investigators and assessed the study quality by the Cochrane risk-of-bias tool. The primary outcome includes the 17-item HAMILTON total score (HAMD-17) and the incidence of adverse events (AEs).

RESULTS

Six high-quality RCTs with 1593 patients were finally included in our analysis. Zuranolone group achieve a notable treatment effect at day15 in HAMD-17 compared with placebo group (MD = -2.69, 95 % CI: -4.45 to -0.94, P < 0.05). For safety, no significant differences existed in the proportion of patients with AEs between zuranolone with placebo (RR = 1.25, 95 % CI: 0.99 to 1.58, P = 0.06).

CONCLUSION

Zuranolone has a significant efficacy in improving depressive symptoms in the short term and is positively correlated with the dosage administered. However, the efficacy of zuranolone decreased significantly when the time of administration was extended. Zuranolone demonstrated a controllable safety issue. But adverse effects increased as the dose of zuranolone was gradually increased to 50 mg.

Advances in Therapeutics to Alleviate Cognitive Decline and Neuropsychiatric Symptoms of Alzheimer's Disease

Dementia exists as a 'progressive clinical syndrome of deteriorating mental function significant enough to interfere with activities of daily living', with the most prevalent type of dementia being Alzheimer's disease (AD), accounting for about 80% of diagnosed cases. AD is associated with an increased risk of comorbidity with other clinical conditions such as hypertension, diabetes, and neuropsychiatric symptoms (NPS) including, agitation, anxiety, and depression as well as increased mortality in late life. For example, up to 70% of patients diagnosed with AD are affected by anxiety. As aging is the major risk factor for AD, this represents a huge global burden in ageing populations. Over the last 10 years, significant efforts have been made to recognize the complexity of AD and understand the aetiology and pathophysiology of the disease as well as biomarkers for early detection. Yet, earlier treatment options, including acetylcholinesterase inhibitors and glutamate receptor regulators, have been limited as they work by targeting the symptoms, with only the more recent FDA-approved drugs being designed to target amyloid-β protein with the aim of slowing down the progression of the disease. However, these drugs may only help temporarily, cannot stop or reverse the disease, and do not act by reducing NPS associated with AD. The first-line treatment options for the management of NPS are selective serotonin reuptake inhibitors/selective noradrenaline reuptake inhibitors (SSRIs/SNRIs) targeting the monoaminergic system; however, they are not rational drug choices for the management of anxiety disorders since the GABAergic system has a prominent role in their development. Considering the overall treatment failures and side effects of currently available medication, there is an unmet clinical need for rationally designed therapies for anxiety disorders associated with AD. In this review, we summarize the current status of the therapy of AD and aim to highlight novel angles for future drug therapy in our ongoing efforts to alleviate the cognitive deficits and NPS associated with this devastating disease.

Zuranolone: A Narrative Review of a New Oral Treatment for Postpartum Depression

PURPOSE

Postpartum depression is a prevalent and overlooked mental disorder. Pathophysiology is thought to originate from a combination of biological and social factors, including hormones, and genetics. The consequences of untreated postpartum depression can be severe and negatively impact maternal and infant health. Zuranolone was approved as an oral agent in August 2023 for the treatment of postpartum depression in adults. The purpose of this article is evaluating the clinical aspects of zuranolone, including safety and efficacy pertaining to the drug and the clinical data that led to its approval.

METHODS

A literature search was conducted using PubMed, Web of Science, and EMBASE with the terms postpartum depression, postpartum depression management, and zuranolone to locate relevant data for this narrative review. The prescribing information of zuranolone and clinicaltrials.gov were also utilized.

FINDINGS

Two Phase III trials (Study 1-NCT04442503 and Study 2-NCT02978326) led to the approval of zuranolone by the Food and Drug Administration (FDA) based on clinically meaningful improvement in depressive symptoms. The trials met their primary endpoint, a change from baseline in HAM-D total score at day 15 (Study 1; 95% CI -6.3 to -1.7, P = 0.001: Study 2; 95% CI (-6.9 to -1.5, P = 0.003).

IMPLICATIONS

Zuranolone, an oral and rapidly acting antidepressant, represents a promising new oral treatment option for individuals with postpartum depression.

Zuranolone, a neuroactive drug, used in the treatment of postpartum depression by modulation of GABAA receptors

BACKGROUND

Postpartum depression [PPD] is a prevalent and debilitating mood disorder that affects mothers in the weeks to months after childbirth. Zuranolone (Zurzuvae) is a novel pharmaceutical agent that was approved by the US FDA on 4 August 2023 for the management of PPD. This review article provides a comprehensive overview of zuranolone, focusing on its dosing, chemistry, mechanism of action, clinical trials, adverse drug reaction, and overall conclusion regarding its utility in the management of PPD. It also discusses the recommended dosing strategies to achieve optimal efficacy while minimizing adverse effects as the dosage regimen of zuranolone is critical for its therapeutic application. Moreover, it gives insights into neurobiological pathways involved in PPD.

METHODOLOGY

Data from randomized controlled trials and observational studies was collected to provide a comprehensive understanding of zuranolone in the management and treatment of PPD.

CONCLUSION

Zuranolone represents a promising therapeutic option for women suffering from postpartum depression. However, ongoing research and post-marketing surveillance are essential to further elucidate its long-term safety and efficacy. The integration of zuranolone into clinical practice may significantly improve the quality of life for mothers facing the challenges of postpartum depression.

Prolonged HPA axis dysregulation in postpartum depression associated with adverse early life experiences: A cross-species translational study

Childhood and adolescent stress increase the risk of postpartum depression (PPD), often providing an increased probability of treatment refractoriness. Nevertheless, the mechanisms linking childhood/adolescent stress to PPD remain unclear. Our study investigated the longitudinal effects of adolescent stress on the hypothalamic-pituitary-adrenal (HPA) axis and postpartum behaviors in mice and humans. Adolescent social isolation prolonged glucocorticoid elevation, leading to long-lasting postpartum behavioral changes in female mice. These changes were unresponsive to current PPD treatments but improved with post-delivery glucocorticoid receptor antagonist treatment. Childhood/adolescent stress significantly impacted HPA axis dysregulation and PPD in human females. Repurposing glucocorticoid receptor antagonists for some cases of treatment-resistant PPD may be considered.

Zuranolone for treatment of major depressive disorder: a systematic review and meta-analysis

Background

Current treatment modalities for Major Depressive Disorder have variable efficacies and a variety of side effects. To amend this, many trials for short term, well tolerated monotherapies are underway. One such option is Zuranolone (SAGE-217), which is a recent FDA approved antidepressant for Post Partum depression (PPD) and is undergoing clinical trials for PPD, major depressive disorder (MDD) and essential tremors (ET).

Objectives

Pool currently available data that compare Zuranolone to Placebo for the treatment of Major Depressive Disorder and evaluate its efficacy and safety profile.

Methods

We retrieved data from PUBMED and SCOPUS from inception to July 2023. We included articles comparing Zuranolone or SAGE 217 with placebo in patients suffering from Major Depressive Disorder. Review Manager 5.4 was used to analyze the outcomes including changes in the Hamilton Depression Rating Scale (HAM-D), Hamilton Anxiety Rating Scale (HAM-A) and Montgomery-Åsberg Depression Rating Scale (MADRS) scores from baseline as well as any treatment emergent adverse events (TEAEs) and severe adverse events.

Results

Our review analyzed 4 trials and the data of 1,357 patients. Patients treated with Zuranolone indicated a statistically significant effect in the change from baseline in HAM-D score (p = 0.0009; MD [95% CI]: -2.03 [-3.23, -0.84]) as well as in MADRS score (p = 0.02; MD [95% CI]: -2.30[-4.31, -0.30]) and HAM-A score (p = 0.03; MD [95% CI]: -1.41[-2.70, -0.11]) on 15th day when compared to the Placebo group. Zuranolone was also significantly associated with a higher response rate (p = 0.0008; OR [95% CI]: 1.63[1.14, 2.35]) and higher remission rate (p = 0.03; OR [95% CI]: 1.65[1.05, 2.59]) when compared with the placebo. As for safety, Zuranolone was significantly associated with 1 or more TEAE (p = 0.006; RR [95% CI]: 1.14[1.04, 1.24]) but an insignificant association with side effects that lead to drug discontinuation (p = 0.70; RR [95% CI]: 1.18[0.51, 2.76]) and serious adverse events (p = 0.48; RR [95% CI]: 1.46 [0.52, 4.10]) when compared with placebo.

Conclusion

Zuranolone is an effective and safe drug for short course major depressive disorder monotherapy. It shows results in 14 days (compared to 2-4 weeks that SSRI's take) and has anti-anxiolytic effects as well. However, only 4 trials have been used for the analysis and the sample size was small. The trials reviewed also cannot determine the long-term effects of the drug. More trials are needed to determine long term effects.

The magnitude and sustainability of treatment benefit of zuranolone on function and well-being as assessed by the SF-36 in adult patients with MDD and PPD: An integrated analysis of 4 randomized clinical trials

BACKGROUND

Major depressive disorder (MDD) and postpartum depression (PPD) are disabling conditions. This integrated analysis of MDD and PPD clinical trials investigated the impact of zuranolone-a positive allosteric modulator of synaptic and extrasynaptic GABAA receptors and neuroactive steroid under investigation for adults with MDD and approved as an oral, once-daily, 14-day treatment course for adults with PPD in the US-on health-related quality of life, including functioning and well-being, as assessed using the 36-item Short Form Health Survey V2 (SF-36).

METHODS

Integrated data from 3 MDD (201B, MOUNTAIN, WATERFALL) and 1 PPD trial (ROBIN) for individual SF-36 domains were compared for zuranolone (30- and 50-mg) vs placebo at Day (D)15 and D42. Comparisons between zuranolone responders (≥50 % reduction from baseline in 17-item Hamilton Depression Rating Scale total score) and nonresponders were assessed.

RESULTS

Overall, 1003 patients were included (zuranolone, n = 504; placebo, n = 499). Significant differences in change from baseline (CFB) to D15 for patients in zuranolone vs placebo groups were observed in 6/8 domains; changes were sustained or improved at D42, with significant CFB differences for all 8 domains. Zuranolone responders had significantly higher CFB scores vs nonresponders for all domains at D15 and D42 (p < 0.001).

LIMITATIONS

Two zuranolone doses were integrated across populations of 2 disease states with potential differences in functioning, comorbidities, and patient demographics. All p-values presented are nominal.

CONCLUSIONS

Integrated data across 4 zuranolone clinical trials showed improvements in functioning and well-being across all SF-36 domains. Benefits persisted after completion of treatment course at D42.

Neurosteroid Modulation of Synaptic and Extrasynaptic GABAA Receptors of the Mouse Nucleus Accumbens

The recent approval of formulations of the endogenous neurosteroid allopregnanolone (brexanolone) and the synthetic neuroactive steroid SAGE-217 (zuranolone) to treat postpartum depression (PPD) has encouraged further research to elucidate why these potent enhancers of GABAAR function are clinically effective in this condition. Dopaminergic projections from the ventral tegmental area (VTA) to the nucleus accumbens are associated with reward/motivation and brain imaging studies report that individuals with PPD show reduced activity of this pathway in response to reward and infant engagement. However, the influence of neurosteroids on GABA-ergic transmission in the nucleus accumbens has received limited attention. Here, we investigate, in the medium spiny neurons (MSNs) of the mouse nucleus accumbens core, the effect of allopregnanolone, SAGE-217 and other endogenous and synthetic steroids of interest on fast phasic and tonic inhibition mediated by synaptic (α1/2βγ2) and extrasynaptic (α4βδ) GABAARs, respectively. We present evidence suggesting the resident tonic current results from the spontaneous opening of δ-GABAARs, where the steroid-enhanced tonic current is GABA-dependent. Furthermore, we demonstrate local neurosteroid synthesis in the accumbal slice preparation and reveal that GABA-ergic neurotransmission of MSNs is influenced by an endogenous neurosteroid tone. Given the dramatic fluctuations in allopregnanolone levels during pregnancy and postpartum, this neurosteroid-mediated local fine-tuning of GABAergic transmission in the MSNs will probably be perturbed.

Pharmacological characterization of SAGE-718, a novel positive allosteric modulator of N-methyl-d-aspartate receptors

BACKGROUND AND PURPOSE

Select neuroactive steroids tune neural activity by modulating excitatory and inhibitory neurotransmission, including the endogenous cholesterol metabolite 24(S)-hydroxycholesterol (24(S)-HC), which is an N-methyl-d-aspartate (NMDA) receptor positive allosteric modulator (PAM). NMDA receptor PAMs are potentially an effective pharmacotherapeutic strategy to treat conditions associated with NMDA receptor hypofunction.

EXPERIMENTAL APPROACH

Using in vitro and in vivo electrophysiological recording experiments and behavioural approaches, we evaluated the effect of SAGE-718, a novel neuroactive steroid NMDA receptor PAM currently in clinical development for the treatment of cognitive impairment, on NMDA receptor function and endpoints that are altered by NMDA receptor hypoactivity and assessed its safety profile.

KEY RESULTS

SAGE-718 potentiated GluN1/GluN2A-D NMDA receptors with equipotency and increased NMDA receptor excitatory postsynaptic potential (EPSP) amplitude without affecting decay kinetics in striatal medium spiny neurons. SAGE-718 increased the rate of unblock of the NMDA receptor open channel blocker ketamine on GluN1/GluN2A in vitro and accelerated the rate of return on the ketamine-evoked increase in gamma frequency band power, as measured with electroencephalogram (EEG), suggesting that PAM activity is driven by increased channel open probability. SAGE-718 ameliorated deficits due to NMDA receptor hypofunction, including social deficits induced by subchronic administration of phencyclidine, and behavioural and electrophysiological deficits from cholesterol and 24(S)-HC depletion caused by 7-dehydrocholesterol reductase inhibition. Finally, SAGE-718 did not produce epileptiform activity in a seizure model or neurodegeneration following chronic dosing.

CONCLUSIONS AND IMPLICATIONS

These findings provide strong evidence that SAGE-718 is a neuroactive steroid NMDA receptor PAM with a mechanism that is well suited as a treatment for conditions associated with NMDA receptor hypofunction.

A Randomized Phase 2 KINETIC Trial Evaluating SAGE-324/BIIB124 in Individuals with Essential Tremor

BACKGROUND

SAGE-324/BIIB124 is an investigational positive allosteric modulator of GABAA receptors.

OBJECTIVE

KINETIC (NCT04305275), a double-blind, randomized, placebo-controlled, phase 2 study, evaluated SAGE-324/BIIB124 in individuals with essential tremor (ET).

METHODS

Individuals aged 18 to 80 years were randomly assigned 1:1 to orally receive 60 mg of SAGE-324/BIIB124 or placebo once daily for 28 days. The primary endpoint was change from baseline in The Essential Tremor Rating Assessment Scale-Performance Subscale (TETRAS-PS) Item 4 (upper-limb tremor) at day 29 with SAGE-324/BIIB124 versus placebo.

RESULTS

Between May 2020 and February 2021, 69 U.S. participants were randomly assigned to receive SAGE-324/BIIB124 (n = 34) or placebo (n = 35). There was a significant reduction from baseline in TETRAS-PS Item 4 at day 29 with SAGE-324/BIIB124 versus placebo (least squares mean [standard error]: -2.31 [0.401] vs. -1.24 [0.349], P = 0.0491). The most common treatment-emergent adverse events included somnolence, dizziness, fatigue, and balance disorder.

CONCLUSION

These results support further development of SAGE-324/BIIB124 for potential ET treatment. © 2024 Sage Therapeutics, Inc and The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

GABAergic mechanisms in alcohol dependence

The target of alcohol's effect on the central nervous system has been sought for more than 50 years in the brain's GABA system. The behavioral and emotional effects of alcohol in humans and rodents are very similar to those of barbiturates and benzodiazepines, and GABAA receptors have been shown to be one of the sites of alcohol action. The mechanisms of GABAergic inhibition have been a hotspot of research but have turned out to be complex and controversial. Genetics support the involvement of some GABAA receptor subunits in the development of alcohol dependence and in alcohol use disorders (AUD). Since the effect of alcohol on the GABAA system resembles that of a GABAergic positive modulator, it may be possible to develop GABAergic drug treatments that could substitute for alcohol. The adaptation mechanisms of the GABA system and the plasticity of the brain are a big challenge for drug development: the drugs that act on GABAA receptors developed so far also may cause adaptation and development of additional addiction. Human polymorphisms should be studied further to get insight about how they affect receptor function, expression or other factors to make reasonable predictions/hypotheses about what non-addictive interventions would help in alcohol dependence and AUD.

Neurosteroids as Novel Anticonvulsants for Refractory Status Epilepticus and Medical Countermeasures for Nerve Agents: A 15-Year Journey to Bring Ganaxolone from Bench to Clinic

This article describes recent advances in the use of neurosteroids as novel anticonvulsants for refractory status epilepticus (RSE) and as medical countermeasures (MCs) for organophosphates and chemical nerve agents (OPNAs). We highlight a comprehensive 15-year journey to bring the synthetic neurosteroid ganaxolone (GX) from bench to clinic. RSE, including when caused by nerve agents, is associated with devastating morbidity and permanent long-term neurologic dysfunction. Although recent approval of benzodiazepines such as intranasal midazolam and intranasal midazolam offers improved control of acute seizures, novel anticonvulsants are needed to suppress RSE and improve neurologic function outcomes. Currently, few anticonvulsant MCs exist for victims of OPNA exposure and RSE. Standard-of-care MCs for postexposure treatment include benzodiazepines, which do not effectively prevent or mitigate seizures resulting from nerve agent intoxication, leaving an urgent unmet medical need for new anticonvulsants for RSE. Recently, we pioneered neurosteroids as next-generation anticonvulsants that are superior to benzodiazepines for treatment of OPNA intoxication and RSE. Because GX and related neurosteroids that activate extrasynaptic GABA-A receptors rapidly control seizures and offer robust neuroprotection by reducing neuronal damage and neuroinflammation, they effectively improve neurologic outcomes after acute OPNA exposure and RSE. GX has been selected for advanced, Biomedical Advanced Research and Development Authority-supported phase 3 trials of RSE and nerve agent seizures. In addition, in mechanistic studies of neurosteroids at extrasynaptic receptors, we identified novel synthetic analogs with features that are superior to GX for current medical needs. Development of new MCs for RSE is complex, tedious, and uncertain due to scientific and regulatory challenges. Thus, further research will be critical to fill key gaps in evaluating RSE and anticonvulsants in vulnerable (pediatric and geriatric) populations and military persons. SIGNIFICANCE STATEMENT: Following organophosphate and nerve agent intoxication, refractory status epilepticus (RSE) occurs despite benzodiazepine treatment. RSE occurs in 40% of status epilepticus patients, with a 35% mortality rate and significant neurological morbidity in survivors. To treat RSE, neurosteroids are better anticonvulsants than benzodiazepines. Our pioneering use of neurosteroids for RSE and nerve agents led us to develop ganaxolone as a novel anticonvulsant and neuroprotectant with significantly improved neurological outcomes. This article describes the bench-to-bedside journey of bringing neurosteroid therapy to patients, with ganaxolone leading the way.

Distinct mechanisms of allopregnanolone and diazepam underlie neuronal oscillations and differential antidepressant effect

The rapid relief of depressive symptoms is a major medical requirement for effective treatments for major depressive disorder (MDD). A decrease in neuroactive steroids contributes to the pathophysiological mechanisms associated with the neurological symptoms of MDD. Zuranolone (SAGE-217), a neuroactive steroid that acts as a positive allosteric modulator of synaptic and extrasynaptic δ-subunit-containing GABAA receptors, has shown rapid-onset, clinically effective antidepressant action in patients with MDD or postpartum depression (PPD). Benzodiazepines, on the other hand, act as positive allosteric modulators of synaptic GABAA receptors but are not approved for the treatment of patients with MDD. It remains unclear how differences in molecular mechanisms contribute to the alleviation of depressive symptoms and the regulation of associated neuronal activity. Focusing on the antidepressant-like effects and neuronal activity of the basolateral amygdala (BLA) and medial prefrontal cortex (mPFC), we conducted a head-to-head comparison study of the neuroactive steroid allopregnanolone and the benzodiazepine diazepam using a mouse social defeat stress (SDS) model. Allopregnanolone but not diazepam exhibited antidepressant-like effects in a social interaction test in SDS mice. This antidepressant-like effect of allopregnanolone was abolished in extrasynaptic GABAA receptor δ-subunit knockout mice (δko mice) subjected to the same SDS protocol. Regarding the neurophysiological mechanism associated with these antidepressant-like effects, allopregnanolone but not diazepam increased theta oscillation in the BLA of SDS mice. This increase did not occur in δko mice. Consistent with this, allopregnanolone potentiated tonic inhibition in BLA interneurons via δ-subunit-containing extrasynaptic GABAA receptors. Theta oscillation in the mPFC of SDS mice was also increased by allopregnanolone but not by diazepam. Finally, allopregnanolone but not diazepam increased frontal theta activity in electroencephalography recordings in naïve and SDS mice. Neuronal network alterations associated with MDD showed decreased frontal theta and beta activity in depressed SDS mice. These results demonstrated that, unlike benzodiazepines, neuroactive steroids increased theta oscillation in the BLA and mPFC through the activation of δ-subunit-containing GABAA receptors, and this change was associated with antidepressant-like effects in the SDS model. Our findings support the notion that the distinctive mechanism of neuroactive steroids may contribute to the rapid antidepressant effects in MDD.

Modulators of GABAA receptor-mediated inhibition in the treatment of neuropsychiatric disorders: past, present, and future

The predominant inhibitory neurotransmitter in the brain, γ-aminobutyric acid (GABA), acts at ionotropic GABAA receptors to counterbalance excitation and regulate neuronal firing. GABAA receptors are heteropentameric channels comprised from subunits derived from 19 different genes. GABAA receptors have one of the richest and well-developed pharmacologies of any therapeutic drug target, including agonists, antagonists, and positive and negative allosteric modulators (PAMs, NAMs). Currently used PAMs include benzodiazepine sedatives and anxiolytics, barbiturates, endogenous and synthetic neurosteroids, and general anesthetics. In this article, I will review evidence that these drugs act at several distinct binding sites and how they can be used to alter the balance between excitation and inhibition. I will also summarize existing literature regarding (1) evidence that changes in GABAergic inhibition play a causative role in major depression, anxiety, postpartum depression, premenstrual dysphoric disorder, and schizophrenia and (2) whether and how GABAergic drugs exert beneficial effects in these conditions, focusing on human studies where possible. Where these classical therapeutics have failed to exert benefits, I will describe recent advances in clinical and preclinical drug development. I will also highlight opportunities to advance a generation of GABAergic therapeutics, such as development of subunit-selective PAMs and NAMs, that are engendering hope for novel tools to treat these devastating conditions.

The efficacy of zuranolone in postpartum depression and major depressive disorder: a review & number needed to treat (NNT) analysis

INTRODUCTION

Major depressive disorder (MDD) is a common and debilitating mental illness. Postpartum depression (PPD) impacts women globally and is one of the most common complications of childbirth that is underdiagnosed and undertreated, adversely impacting the mental health of women, children, and partners.Available antidepressant medications require weeks to months before showing effect. In this setting, zuranolone, an oral neuroactive steroid and a positive allosteric modulator of GABAA receptors, is an attractive alternative as a rapid-acting antidepressant treatment.

AREAS COVERED

This article reviews zuranolone (SAGE217), focusing on available clinical studies in individuals with PPD and MDD. This paper adds to the extant literature by presenting the efficacy data as Number Needed to Treat (NNT) to facilitate indirect comparisons with other antidepressants.

EXPERT OPINION

Zuranolone is a novel rapid-acting (i.e. two week course) oral antidepressant for the treatment of adults with PPD with ongoing clinical trials evaluating its efficacy in adults with MDD. Zuranolone is well tolerated with no significant safety concerns in any clinical trials completed to date. Zuranolone will be scheduled by the Drug Enforcement Agency (DEA).

Efficacy and safety of zuranolone for the treatment of depression: A systematic review and meta-analysis

Major depressive disorder (MDD) and postpartum depression (PPD) are common and burdensome conditions. This study aims to evaluate the efficacy and safety of zuranolone, a neuroactive steroid γ-aminobutyric acid type A receptors-positive allosteric modulator, in treating MDD and PPD. A comprehensive literature search was conducted until September 2023, identifying seven randomized controlled trials (RCTs). The results demonstrated that zuranolone significantly decreased Hamilton Rating Scale for Depression (HAM-D) scores in patients with PPD or MDD at day 15 (concluding the 14-day course) and day 42-45 (4 weeks after treatment cessation) compared with the placebo, albeit exhibiting a diminishing trend. Moreover, a higher percentage of patients with PPD or MDD achieved HAM-D response and remission with zuranolone treatment compared with placebo at day 15. However, zuranolone did not significantly increase the proportion of MDD patients achieving HAM-D remission at 42/43 days. Adverse events (AEs) such as somnolence, dizziness, and sedation were linked to zuranolone, with a higher but not statistically significant rate of discontinuation due to AEs in the zuranolone group. Overall, our findings support the rapid antidepressant effects of zuranolone in MDD and PPD, along with a relatively favorable safety and tolerability. Large-scale longitudinal RCTs are needed to evaluate the long-term efficacy of zuranolone.

Efficacy and safety of zuranolone co-initiated with an antidepressant in adults with major depressive disorder: results from the phase 3 CORAL study

Major depressive disorder (MDD) is a mental health disorder that can cause disability and functional impairment that standard-of-care (SOC) antidepressant therapies (ADTs) can take weeks to treat. Zuranolone is a neuroactive steroid and positive allosteric modulator of synaptic and extrasynaptic γ-aminobutyric acid (GABA) type A receptors approved as an oral, once-daily, 14-day treatment course in adults with postpartum depression and under investigation in adults with MDD. The phase 3 CORAL Study (NCT04476030) evaluated the efficacy and safety of zuranolone 50 mg co-initiated with SOC ADT (zuranolone+ADT) vs placebo co-initiated with SOC ADT (placebo+ADT) in adults with MDD. Patients were randomized 1:1 to once-daily, blinded zuranolone+ADT or placebo+ADT for 14 days, then continued open-label SOC ADT for 28 more days. The primary endpoint was change from baseline (CFB) in the 17-item Hamilton Rating Scale for Depression (HAMD-17) total score at Day 3. Among 425 patients in the full analysis set, CFB in HAMD-17 total score at Day 3 was significantly improved with zuranolone+ADT vs placebo+ADT (least squares mean [standard error], -8.9 [0.39] vs -7.0 [0.38]; p = 0.0004). The majority of patients receiving zuranolone+ADT that experienced treatment-emergent adverse events (TEAEs) reported mild or moderate events. The most common TEAEs present in ≥10% of patients in either zuranolone+ADT or placebo+ADT groups were somnolence, dizziness, headache, and nausea. These results demonstrate that zuranolone+ADT provided more rapid improvement in depressive symptoms compared with placebo+ADT in patients with MDD, with a safety profile consistent with previous studies. Clinical trial registration: ClinicalTrials.gov identifier: NCT04476030.

Zuranolone - synthetic neurosteroid in treatment of mental disorders: narrative review

With each passing year, the number of people suffering from mental disorders grows at a disturbing speed. Neuroactive steroids are a new promising group of drugs with the potential for use in many diseases like postpartum depression, postnatal psychosis, major depression, insomnia, bipolar disorder, and Parkinson's tremor, due to their ability to modulate the activity of GABAA receptor. Neurosteroids are progesterone metabolites that are synthesized from cholesterol or steroid hormones in various brain regions. They regulate neuronal development, regeneration, and neurotransmission. They are implicated in mood disorders, anxiety disorders, schizophrenia, PTSD, and impulsive aggression. Neurosteroids have been studied for their potential to prevent or treat neurodegenerative diseases such as Alzheimer's disease and HIV-associated dementia. They can promote neurogenesis, neuronal survival, myelination, and memory function. They can also affect the growth and sensitivity of hormone-dependent brain tumors such as gliomas. Zuranolone, a newly registered neurosteroid drug has shown huge flexibility in both clinical and ambulatory treatment thanks to its pharmacokinetic traits, especially the possibility for oral administration, unlike its predecessor Brexanolone. Zuranolone is a synthetic positive allosteric modulator of the GABAA receptor that can be taken orally. The review aims to summarize the current knowledge on zuranolone as a novel neurosteroid drug for various mental disorders, especially for postpartum mental disorders for which this drug was meant originally. It covers studies indexed in the PubMed, Scopus, and Web of Science databases published since 2017. Keywords used in the search, as well as inclusion and exclusion criteria, are given in the aims and methodology section. The review explains the evidence for the role of neurosteroids, especially allopregnanolone, in the pathophysiology and treatment of postpartum depression. It discusses the mechanisms of neurosteroid action, the changes in neurosteroid levels during pregnancy and postpartum, and the clinical trials of brexanolone and zuranolone, two synthetic analogs of allopregnanolone, for postpartum depression. It provides an overview of the biosynthesis and metabolism of neurosteroids in the central and peripheral nervous system. Furthermore, it explains the different sources and pathways of neurosteroid production and the factors that influence their synthesis and regulation, such as stress, hormones, drugs, and genetic variations. The review also explores the potential relevance of neurosteroids for other psychiatric disorders, such as major depression, bipolar disorder, post-traumatic stress disorder (PTSD), schizophrenia, and premenstrual dysphoric disorder. Finally, it highlights the associations between neurosteroid levels and symptom severity and the effects of neurosteroid modulation on mood, cognition, and neuroplasticity.

Association between NTRK2 Polymorphisms, Hippocampal Volumes and Treatment Resistance in Major Depressive Disorder

Despite the increasing availability of antidepressant drugs, a high rate of patients with major depression (MDD) does not respond to pharmacological treatments. Brain-derived neurotrophic factor (BDNF)-tyrosine receptor kinase B (TrkB) signaling is thought to influence antidepressant efficacy and hippocampal volumes, robust predictors of treatment resistance. We therefore hypothesized the possible role of BDNF and neurotrophic receptor tyrosine kinase 2 (NTRK2)-related polymorphisms in affecting both hippocampal volumes and treatment resistance in MDD. A total of 121 MDD inpatients underwent 3T structural MRI scanning and blood sampling to obtain genotype information. General linear models and binary logistic regressions were employed to test the effect of genetic variations related to BDNF and NTRK2 on bilateral hippocampal volumes and treatment resistance, respectively. Finally, the possible mediating role of hippocampal volumes on the relationship between genetic markers and treatment response was investigated. A significant association between one NTRK2 polymorphism with hippocampal volumes and antidepressant response was found, with significant indirect effects. Our results highlight a possible mechanistic explanation of antidepressant action, possibly contributing to the understanding of MDD pathophysiology.

Importance of achieving rapid treatment response in major depressive disorder

Major depressive disorder (MDD) is a leading contributor to disability worldwide and is associated with increased morbidity and mortality. Current pharmacologic treatment options may be ineffective for some patients and can pose several limitations and challenges, including suboptimal response and slow onset of action. Many of these therapies can take 6 to 8 weeks for patients to achieve response and 12 weeks or longer to demonstrate full clinical benefit. Delays in depressive symptom resolution are associated with poor symptomatic and functional outcomes, decreased quality of life, and increased burden on the healthcare system. Achieving response and remission of symptoms soon after diagnosis and treatment is associated with lower rates of relapse and a greater likelihood of functional recovery. An unmet need exists for innovative treatments that offer rapid and sustained effects. This editorial discusses the benefits of rapid improvement in depressive symptoms with available and investigational agents for patients with MDD.

Neurosteroids and translocator protein 18 kDa (TSPO) in depression: implications for synaptic plasticity, cognition, and treatment options

There is need for novel fast acting treatment options in affective disorders. 3α-reduced neurosteroids such as allopregnanolone are powerful positive allosteric modulators of GABAA receptors and target also extrasynaptic receptors. Their synthesis is mediated by the translocator protein 18 kDa (TSPO). TSPO ligands not only promote endogenous neurosteroidogenesis, but also exert a broad spectrum of functions involving modulation of mitochondrial activity and acting as anti-inflammatory and neuroregenerative agents. Besides affective symptoms, in depression cognitive impairment can be frequently observed, which may be ameliorated through targeting of extrasynaptic GABAA receptors either via TSPO ligands or exogenously administered 3α-reduced neurosteroids. Interestingly, recent findings indicate an enhanced activation of the complement system, e.g., enhanced expression of C1q, both in depression and dementia. It is of note that benzodiazepines have been shown to reduce long-term potentiation and to cause cognitive decline. Intriguingly, TSPO may be crucial in mediating the effects of benzodiazepines on synaptic pruning. Here, we discuss how benzodiazepines and TSPO may interfere with synaptic pruning. Moreover, we highlight recent developments of TSPO ligands and 3α-reduced neurosteroids as therapeutic agents. Etifoxine is the only clinically available TSPO ligand so far and has been studied in anxiety disorders. Regarding 3α-reduced neurosteroids, brexanolone, an intravenous formulation of allopregnanolone, has been approved for the treatment of postpartum depression and zuranolone, an orally available 3α-reduced neurosteroid, is currently being studied in major depressive disorder and postpartum depression. As such, 3α-reduced neurosteroids and TSPO ligands may constitute promising treatment approaches for affective disorders.

The efficacy and safety of some new GABAkines for treatment of depression: A systematic review and meta-analysis from randomized controlled trials

Positive allosteric modulators of γ-aminobutyric acid-A (GABAA) receptors, or GABAkines, play important roles in the treatment of depression, epilepsy, insomnia, and other disorders. Recently, some new GABAkines (zuranolone and brexanolone) have been administrated to patients with major depressive disorder (MDD) or postpartum depression (PPD) in randomized controlled trials (RCTs). This study aims to systematically review and examine the efficacy and safety of zuranolone or brexanolone for treatment of depression. A systematic literature retrieval was conducted through August 20, 2023. RCTs evaluating the efficacy and safety of zuranolone or brexanolone for treatment of depression were included. Eight studies (nine reports) were identified in the study. The percentages of patients with PPD achieving Hamilton Depression Rating Scale (HAM-D) response and remission were significantly higher after brexanolone or zuranolone administration compared with placebo at different points. The percentages of patients with MDD achieving HAM-D response and remission were significantly increased during the zuranolone treatment period compared with placebo. In addition, zuranolone caused more adverse events in patients with MDD compared with placebo. Our findings support the effects of brexanolone on improving the core symptoms of depression in patients with PPD, and the potential of zuranolone in treating patients with MDD or PPD.

Preclinical and clinical pharmacology of brexanolone (allopregnanolone) for postpartum depression: a landmark journey from concept to clinic in neurosteroid replacement therapy

This article describes the critical role of neurosteroids in postpartum depression (PPD) and outlines the landmark pharmacological journey of brexanolone as a first-in-class neurosteroid antidepressant with significant advantages over traditional antidepressants. PPD is a neuroendocrine disorder that affects about 20% of mothers after childbirth and is characterized by symptoms including persistent sadness, fatigue, dysphoria, as well as disturbances in cognition, emotion, appetite, and sleep. The main pathology behind PPD is the postpartum reduction of neurosteroids, referred to as neurosteroid withdrawal, a concept pioneered by our preclinical studies. We developed neurosteroid replacement therapy (NRT) as a rational approach for treating PPD and other conditions related to neurosteroid deficiency, unveiling the power of neurosteroids as novel anxiolytic-antidepressants. The neurosteroid, brexanolone (BX), is a progesterone-derived allopregnanolone that rapidly relieves anxiety and mood deficits by activating GABA-A receptors, making it a transformational treatment for PPD. In 2019, the FDA approved BX, an intravenous formulation of allopregnanolone, as an NRT to treat PPD. In clinical studies, BX significantly improved PPD symptoms within hours of administration, with tolerable side effects including headache, dizziness, and somnolence. We identified the molecular mechanism of BX in a neuronal PPD-like milieu. The mechanism of BX involves activation of both synaptic and extrasynaptic GABA-A receptors, which promote tonic inhibition and serve as a key target for PPD and related conditions. Neurosteroids offer several advantages over traditional antidepressants, including rapid onset, unique mechanism, and lack of tolerance upon repeated use. Some limitations of BX therapy include lack of aqueous solubility, limited accessibility, hospitalization for treatment, lack of oral product, and serious adverse events at high doses. However, the unmet need for synthetic neurosteroids to address this critical condition supersedes these limitations. Recently, we developed novel hydrophilic neurosteroids with a superior profile and improved drug delivery. Overall, approval of BX is a major milestone in the field of neurotherapeutics, paving the way for the development of novel synthetic neurosteroids to treat depression, epilepsy, and status epilepticus.

Clinical specificity profile for novel rapid acting antidepressant drugs

Mood disorders are recurrent/chronic diseases with variable clinical remission rates. Available antidepressants are not effective in all patients and often show a relevant response latency, with a range of adverse events, including weight gain and sexual dysfunction. Novel rapid agents were developed with the aim of overcoming at least in part these issues. Novel drugs target glutamate, gamma-aminobutyric acid, orexin, and other receptors, providing a broader range of pharmacodynamic mechanisms, that is, expected to increase the possibility of personalizing treatments on the individual clinical profile. These new drugs were developed with the aim of combining a rapid action, a tolerable profile, and higher effectiveness on specific symptoms, which were relatively poorly targeted by standard antidepressants, such as anhedonia and response to reward, suicidal ideation/behaviours, insomnia, cognitive deficits, and irritability. This review discusses the clinical specificity profile of new antidepressants, namely 4-chlorokynurenine (AV-101), dextromethorphan-bupropion, pregn-4-en-20-yn-3-one (PH-10), pimavanserin, PRAX-114, psilocybin, esmethadone (REL-1017/dextromethadone), seltorexant (JNJ-42847922/MIN-202), and zuranolone (SAGE-217). The main aim is to provide an overview of the efficacy/tolerability of these compounds in patients with mood disorders having different symptom/comorbidity patterns, to help clinicians in the optimization of the risk/benefit ratio when prescribing these drugs.

Zuranolone for the Treatment of Adults With Major Depressive Disorder: A Randomized, Placebo-Controlled Phase 3 Trial

OBJECTIVE

This study assessed the efficacy and safety of a 14-day treatment course of once-daily zuranolone 50 mg, an investigational oral positive allosteric modulator of the γ-aminobutyric acid type A (GABAA) receptor, for the treatment of major depressive disorder.

METHODS

Patients 18-64 years of age with severe major depressive disorder were enrolled in this randomized, double-blind, placebo-controlled trial. Patients self-administered zuranolone 50 mg or placebo once daily for 14 days. The primary endpoint was change from baseline in total score on the 17-item Hamilton Depression Rating Scale (HAM-D) at day 15. Safety and tolerability were assessed by incidence of adverse events.

RESULTS

Of 543 randomized patients, 534 (266 in the zuranolone group, 268 in the placebo group) constituted the full analysis set. Compared with patients in the placebo group, patients in the zuranolone group demonstrated a statistically significant improvement in depressive symptoms at day 15 (least squares mean change from baseline HAM-D score, -14.1 vs. -12.3). Numerically greater improvements in depressive symptoms for zuranolone versus placebo were observed by day 3 (least squares mean change from baseline HAM-D score, -9.8 vs. -6.8), which were sustained at all visits throughout the treatment and follow-up periods of the study (through day 42, with the difference remaining nominally significant through day 12). Two patients in each group experienced a serious adverse event; nine patients in the zuranolone group and four in the placebo group discontinued treatment due to adverse events.

CONCLUSIONS

Zuranolone at 50 mg/day elicited a significantly greater improvement in depressive symptoms at day 15, with a rapid time to effect (day 3). Zuranolone was generally well tolerated, with no new safety findings compared with previously studied lower dosages. These findings support the potential of zuranolone in treating adults with major depressive disorder.