Search

Introduction: Cyclin-dependent kinase-Like 5 (CDKL5) deficiency disorder (CDD) is a rare neurodevelopmental condition commonly characterized by drug-resistant, refractory epilepsy, and seizures beginning in infancy. Most patients use multiple drugs, yet seizures remain difficult to control. So far, no conventional anti-seizure medications have been proven to be effective in individuals with CDD, in well-conducted studies. Areas covered: In this review, the authors assess the pharmacokinetics, early studies and appraise a recent study investigating the efficacy and safety of the oral suspension of ganaxolone (3α-hydroxy-3β-methyl-5α-pregnan-20-one) as an adjunctive therapy to treat seizures in CDD. The authors also discuss the impact of this drug on non-seizure outcomes. Expert opinion: Ganaxolone is a neuroactive 3β-methylated synthetic analogue of the potent agonist of gamma-aminobutyric acid type A receptors, allopregnanolone. Ganaxolone is the only drug that has been studied in a robust randomized controlled trial and been proven to be effective in this population. [ABSTRACT FROM AUTHOR]

Ganaxolone has exhibited potential in managing seizures for epilepsy. This systematic review and meta-analysis aim to assess both the safety and efficacy of Ganaxolone for refractory epilepsy. A thorough search of electronic databases was conducted to identify relevant randomized controlled trials involving patients with drug-resistant focal epilepsy and CDKL5 deficiency disorder. Efficacy and safety outcomes were extracted from the selected studies. Cochrane Review Manager was utilized for data synthesis and analysis, with risk ratios and mean differences calculated to evaluate the efficacy and safety profile of Ganaxolone. The meta-analysis included a total of five randomized controlled trials. Ganaxolone exhibited significant efficacy in reducing seizure frequency by at least 50% from baseline [RR 0.90 (95% CI: 0.83, 0.98), p = 0.02]. However, the results did not reach significance for reducing 28-day seizure frequency [Mean Difference −1.45 (95% CI: −3.39, 0.49), p = 0.14]. Ganaxolone exhibited a positive safety profile, with no statistically significant occurrence of adverse events [RR 1.30 (95% CI: 0.93, 1.83), p = 0.12] and adverse events leading to discontinuation of the study drug [RR 1.01 (95% CI: 0.42, 2.39), p = 0.99] compared to placebo. Ganaxolone presents itself as a viable therapeutic option for refractory epilepsy, showing efficacy in reducing seizure frequency and exhibited a favorable safety profile. CRD42023434883 [ABSTRACT FROM AUTHOR]

Ganaxolone, a neuroactive steroid anticonvulsant that modulates both synaptic and extrasynaptic γ‐aminobutyric acid type A (GABAA) receptors, is in development for treatment of status epilepticus (SE) and rare epileptic disorders, and has been approved in the United States for treatment of seizures associated with cyclin‐dependent kinase‐like 5 deficiency disorder in patients ≥2 years old. This phase 1 study in 36 healthy volunteers evaluated the pharmacokinetics, pharmacodynamics, and safety of intravenous ganaxolone administered as a (i) single bolus, (ii) infusion, and (iii) bolus followed by continuous infusion. After a single bolus over 2 minutes (20 mg) or 5 minutes (10 or 30 mg), ganaxolone was detected in plasma with a median Tmax of 5 minutes, whereas a 60‐minute infusion (10 or 30 mg) or a bolus (6 mg over 5 minutes) followed by infusion (20 mg/h) for 4 hours achieved a median Tmax of approximately 1 and 3 hours, respectively. Cmax was dose and administration‐time dependent, ranging from 73.8 ng/mL (10 mg over 5 minutes) to 1240 ng/mL (30 mg over 5 minutes). Bolus doses above 10 mg of ganaxolone markedly influenced the bispectral index score with a rapid decline; smaller changes occurred on the Modified Observer's Assessment of Alertness/Sedation scale and in quantitative electroencephalogram. Most adverse events were of mild severity, with 2 events of moderate severity; none were reported as serious. No effects on systemic hemodynamics or respiratory functions were reported. Overall, ganaxolone was generally well tolerated at the doses studied and demonstrated pharmacokinetic and pharmacodynamic properties suitable to treat SE. [ABSTRACT FROM AUTHOR]

Objective: Absence seizures result from aberrant thalamocortical processing that confers synchronous, bilateral spike-and-wave discharges (SWDs) and behavioral arrest. Previous work has demonstrated that SWDs can result from enhanced thalamic tonic inhibition, consistent with the mechanism of first-line antiabsence drugs that target thalamic low-voltage-activated calcium channels. However, nearly half of patients with absence epilepsy are unresponsive to first-line medications. In this study we evaluated the role of cortical tonic inhibition and its manipulation on absence seizure expression. Methods: We used video-electroencephalogram (EEG) monitoring to show that mice with a γ-aminobutyric acid type A (GABAA) receptor mutation (γ2R43Q) display absence seizures. Voltage-clamp recordings in brain slices from wild type and γ2R43Q mice were used to evaluate the amount of tonic inhibition and its selective pharmacological modulation. Finally, we determined whether modulating tonic inhibition controls seizure expression. Results: γ2R43Q mice completely lack tonic inhibition in principal neurons of both layer 2/3 cortex and ventrobasal thalamus. Blocking cortical tonic inhibition in wild type mice is sufficient to elicit SWDs. Tonic inhibition in slices from γ2R43Q mice could be rescued in a dose-dependent fashion by the synthetic neurosteroid ganaxolone. Low-dose ganaxolone suppressed seizures in γ2R43Q mice. Conclusions: Our data suggest that reduced cortical tonic inhibition promotes absence seizures and that normal function can be restored via selective pharmacological rescue. These results, together with previous findings, suggest that deviations of tonic inhibition either above or below an optimal set point can contribute to absence epilepsy. Returning the thalamocortical system to this set point may provide a novel treatment for refractory absence epilepsy. [ABSTRACT FROM AUTHOR]

Abstract Background Phelan–McDermid syndrome (PMS) is a neurodevelopmental disorder characterized by developmental delay, intellectual disability, and autistic-like behaviors and is primarily caused by haploinsufficiency of SHANK3 gene. Currently, there is no specific treatment for PMS, highlighting the need for a better understanding of SHANK3 functions and the underlying pathophysiological mechanisms in the brain. We hypothesize that SHANK3 haploinsufficiency may lead to alterations in the inhibitory system, which could be linked to the excitatory/inhibitory imbalance observed in models of autism spectrum disorder (ASD). Investigation of these neuropathological features may shed light on the pathogenesis of PMS and potential therapeutic interventions. Methods We recorded local field potentials and visual evoked responses in the visual cortex of Shank3∆11−/− mice. Then, to understand the impact of Shank3 in inhibitory neurons, we generated Pv-cre+/− Shank3 Fl/Wt conditional mice, in which Shank3 was deleted in parvalbumin-positive neurons. We characterized the phenotype of this murine model and we compared this phenotype before and after ganaxolone administration. Results We found, in the primary visual cortex, an alteration of the gain control of Shank3 KO compared with Wt mice, indicating a deficit of inhibition on pyramidal neurons. This alteration was rescued after the potentiation of GABAA receptor activity by Midazolam. Behavioral analysis showed an impairment in grooming, memory, and motor coordination of Pv-cre+/− Shank3 Fl/Wt compared with Pv-cre+/− Shank3 Wt/Wt mice. These deficits were rescued with ganaxolone, a positive modulator of GABAA receptors. Furthermore, we demonstrated that treatment with ganaxolone also ameliorated evocative memory deficits and repetitive behavior of Shank3 KO mice. Limitations Despite the significant findings of our study, some limitations remain. Firstly, the neurobiological mechanisms underlying the link between Shank3 deletion in PV neurons and behavioral alterations need further investigation. Additionally, the impact of Shank3 on other classes of inhibitory neurons requires further exploration. Finally, the pharmacological activity of ganaxolone needs further characterization to improve our understanding of its potential therapeutic effects. Conclusions Our study provides evidence that Shank3 deletion leads to an alteration in inhibitory feedback on cortical pyramidal neurons, resulting in cortical hyperexcitability and ASD-like behavioral problems. Specifically, cell type-specific deletion of Shank3 in PV neurons was associated with these behavioral deficits. Our findings suggest that ganaxolone may be a potential pharmacological approach for treating PMS, as it was able to rescue the behavioral deficits in Shank3 KO mice. Overall, our study highlights the importance of investigating the role of inhibitory neurons and potential therapeutic interventions in neurodevelopmental disorders such as PMS.

Abstract Objective Epilepsy is one of the most common and refractory neurological disorders globally. Ganaxolone, a neuroactive steroid that enhances GABAergic inhibition, has been tested in many trials for the resolution of refractory epilepsy. Based on these, our study implemented a meta‐analysis to evaluate the general benefit of ganaxolone for refractory epilepsy. Methods EMBASE, Medline, Scopus, Cochrane Library, and Clinicaltrials.gov were searched for relevant randomized controlled trials (RCTs) up to June 20, 2022. The risk ratio (RR) and standard mean difference (SMD) were analyzed using dichotomous and continuous outcomes, respectively with a random effect model. Trial sequential analysis (TSA) was also performed to judge the reliability of results. Results We totally collected 659 patients from four RCTs to evaluate the efficacy and safety of ganaxolone. As results showed, ≥50% reduction in mean seizure frequency has improved significantly compared with placebo (RR = 1.60, 95%CI: 1.02–2.49, p = 0.04, I2 = 30%), which is supported by TSA. However, the percentage of seizure‐free days shows no statistical significance (p = 0.36). For safety outcomes, adverse events (AEs), serious adverse events, and AE leading to study drug discontinuation all revealed no obvious difference between ganaxolone and placebo (p > 0.05). Significance Based on our research, we have observed that ganaxolone is safe and has potential efficacy in the treatment of refractory epilepsy, waiting for further studies.

Developmental and epileptic encephalopathies (DEEs) are rare neurodevelopmental disorders characterised by early-onset and often intractable seizures and developmental delay/regression, and include Dravet syndrome and Lennox–Gastaut syndrome (LGS). Rufinamide, fenfluramine, stiripentol, cannabidiol and ganaxolone are antiseizure medications (ASMs) with diverse mechanisms of action that have been approved for treating specific DEEs. Rufinamide is thought to suppress neuronal hyperexcitability by preventing the functional recycling of voltage-gated sodium channels from the inactivated to resting state. It is licensed for adjunctive treatment of seizures associated with LGS. Fenfluramine increases extracellular serotonin levels and may reduce seizures via activation of specific serotonin receptors and positive modulation of the sigma-1 receptor. Fenfluramine is licensed for adjunctive treatment of seizures associated with Dravet syndrome and LGS. Stiripentol is a positive allosteric modulator of type-A gamma-aminobutyric acid (GABAA) receptors. As a broad-spectrum inhibitor of cytochrome P450 enzymes, its antiseizure effects may additionally arise through pharmacokinetic interactions with co-administered ASMs. Stiripentol is licensed for treating seizures associated with Dravet syndrome in patients taking clobazam and/or valproate. The mechanism(s) of action of cannabidiol remains largely unclear although multiple targets have been proposed, including transient receptor potential vanilloid 1, G protein-coupled receptor 55 and equilibrative nucleoside transporter 1. Cannabidiol is licensed as adjunctive treatment in conjunction with clobazam for seizures associated with Dravet syndrome and LGS, and as adjunctive treatment of seizures associated with tuberous sclerosis complex. Like stiripentol, ganaxolone is a positive allosteric modulator at GABAA receptors. It has recently been licensed in the USA for the treatment of seizures associated with cyclin-dependent kinase-like 5 deficiency disorder. Greater understanding of the causes of DEEs has driven research into the potential use of other novel and repurposed agents. Putative ASMs currently in clinical development for use in DEEs include soticlestat, carisbamate, verapamil, radiprodil, clemizole and lorcaserin. [ABSTRACT FROM AUTHOR]

Background: Phelan–McDermid syndrome (PMS) is a neurodevelopmental disorder characterized by developmental delay, intellectual disability, and autistic-like behaviors and is primarily caused by haploinsufficiency of SHANK3 gene. Currently, there is no specific treatment for PMS, highlighting the need for a better understanding of SHANK3 functions and the underlying pathophysiological mechanisms in the brain. We hypothesize that SHANK3 haploinsufficiency may lead to alterations in the inhibitory system, which could be linked to the excitatory/inhibitory imbalance observed in models of autism spectrum disorder (ASD). Investigation of these neuropathological features may shed light on the pathogenesis of PMS and potential therapeutic interventions. Methods: We recorded local field potentials and visual evoked responses in the visual cortex of Shank3∆11−/− mice. Then, to understand the impact of Shank3 in inhibitory neurons, we generated Pv-cre+/−Shank3Fl/Wt conditional mice, in which Shank3 was deleted in parvalbumin-positive neurons. We characterized the phenotype of this murine model and we compared this phenotype before and after ganaxolone administration. Results: We found, in the primary visual cortex, an alteration of the gain control of Shank3 KO compared with Wt mice, indicating a deficit of inhibition on pyramidal neurons. This alteration was rescued after the potentiation of GABAA receptor activity by Midazolam. Behavioral analysis showed an impairment in grooming, memory, and motor coordination of Pv-cre+/−Shank3Fl/Wt compared with Pv-cre+/−Shank3Wt/Wt mice. These deficits were rescued with ganaxolone, a positive modulator of GABAA receptors. Furthermore, we demonstrated that treatment with ganaxolone also ameliorated evocative memory deficits and repetitive behavior of Shank3 KO mice. Limitations: Despite the significant findings of our study, some limitations remain. Firstly, the neurobiological mechanisms underlying the link between Shank3 deletion in PV neurons and behavioral alterations need further investigation. Additionally, the impact of Shank3 on other classes of inhibitory neurons requires further exploration. Finally, the pharmacological activity of ganaxolone needs further characterization to improve our understanding of its potential therapeutic effects. Conclusions: Our study provides evidence that Shank3 deletion leads to an alteration in inhibitory feedback on cortical pyramidal neurons, resulting in cortical hyperexcitability and ASD-like behavioral problems. Specifically, cell type-specific deletion of Shank3 in PV neurons was associated with these behavioral deficits. Our findings suggest that ganaxolone may be a potential pharmacological approach for treating PMS, as it was able to rescue the behavioral deficits in Shank3 KO mice. Overall, our study highlights the importance of investigating the role of inhibitory neurons and potential therapeutic interventions in neurodevelopmental disorders such as PMS. [ABSTRACT FROM AUTHOR]

Objective: Epilepsy is one of the most common and refractory neurological disorders globally. Ganaxolone, a neuroactive steroid that enhances GABAergic inhibition, has been tested in many trials for the resolution of refractory epilepsy. Based on these, our study implemented a meta‐analysis to evaluate the general benefit of ganaxolone for refractory epilepsy. Methods: EMBASE, Medline, Scopus, Cochrane Library, and Clinicaltrials.gov were searched for relevant randomized controlled trials (RCTs) up to June 20, 2022. The risk ratio (RR) and standard mean difference (SMD) were analyzed using dichotomous and continuous outcomes, respectively with a random effect model. Trial sequential analysis (TSA) was also performed to judge the reliability of results. Results: We totally collected 659 patients from four RCTs to evaluate the efficacy and safety of ganaxolone. As results showed, ≥50% reduction in mean seizure frequency has improved significantly compared with placebo (RR = 1.60, 95%CI: 1.02–2.49, p = 0.04, I2 = 30%), which is supported by TSA. However, the percentage of seizure‐free days shows no statistical significance (p = 0.36). For safety outcomes, adverse events (AEs), serious adverse events, and AE leading to study drug discontinuation all revealed no obvious difference between ganaxolone and placebo (p > 0.05). Significance: Based on our research, we have observed that ganaxolone is safe and has potential efficacy in the treatment of refractory epilepsy, waiting for further studies. [ABSTRACT FROM AUTHOR]

Objective: Absence seizures result from aberrant thalamocortical processing that confers synchronous, bilateral spike-and-wave discharges (SWDs) and behavioral arrest. Previous work has demonstrated that SWDs can result from enhanced thalamic tonic inhibition, consistent with the mechanism of first-line antiabsence drugs that target thalamic low-voltage-activated calcium channels. However, nearly half of patients with absence epilepsy are unresponsive to first-line medications. In this study we evaluated the role of cortical tonic inhibition and its manipulation on absence seizure expression. Methods: We used video-electroencephalogram (EEG) monitoring to show that mice with a γ-aminobutyric acid type A (GABAA) receptor mutation (γ2R43Q) display absence seizures. Voltage-clamp recordings in brain slices from wild type and γ2R43Q mice were used to evaluate the amount of tonic inhibition and its selective pharmacological modulation. Finally, we determined whether modulating tonic inhibition controls seizure expression. Results: γ2R43Q mice completely lack tonic inhibition in principal neurons of both layer 2/3 cortex and ventrobasal thalamus. Blocking cortical tonic inhibition in wild type mice is sufficient to elicit SWDs. Tonic inhibition in slices from γ2R43Q mice could be rescued in a dose-dependent fashion by the synthetic neurosteroid ganaxolone. Low-dose ganaxolone suppressed seizures in γ2R43Q mice. Conclusions: Our data suggest that reduced cortical tonic inhibition promotes absence seizures and that normal function can be restored via selective pharmacological rescue. These results, together with previous findings, suggest that deviations of tonic inhibition either above or below an optimal set point can contribute to absence epilepsy. Returning the thalamocortical system to this set point may provide a novel treatment for refractory absence epilepsy.

Copyright of Child Neurology / Neurologia Dziecięca is the property of BiFolium and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

• Fibromyalgia is a poorly known central syndrome characterized by chronic pain. • We have developed a pathogenesis model based on a thalamocortical loop. • The loop generates nociplastic pain for GABAergic weakening. • The model explains female prevalence and correlation with stress. • It suggests the use of neurosteroids as an innovative treatment for fibromyalgia. Fibromyalgia (FM) is a central chronic pain syndrome with fatigue, sleep disorders, and other symptoms. It has 1–5 % worldwide prevalence, 3:1 female-to-male ratio, and shows correlation with stress. The pathogenic mechanism is unknown, biomarkers are missing, and patient management is extremely difficult due to the lack of resolutive therapies. We developed a pathogenic model of FM based on a thalamocortical loop network that shifts from monostability to bistability for decreasing GABAergic and increasing glutamatergic transmission, leading to the appearance of a high-firing-rate steady state that represents FM altered central pain processing. Here, we propose the hypothesis that the pathogenic GABA/glutamate unbalance could be effectively counteracted by the use of neurosteroid drugs acting as positive allosteric modulators of both synaptic and extrasynaptic GABA A receptors. Our hypothesis is based on evidence suggesting the involvement of large fluctuations of gonadal neurosteroids (notably brain allopregnanolone withdrawal in perimenstrual/peripartum periods) and of adrenocortical hormones (notably cortisol rise during stress activation) in FM pathogenesis and in the regulation of central GABA/glutamate balance. Therefore, our hypothesis provides a link between FM clinical features (such as female prevalence and correlation with stress) and endocrine influences on neurotransmission, suggesting the use of neurosteroid drugs for the treatment of the disease. [ABSTRACT FROM AUTHOR]

BackgroundGamma-aminobutyric acid (GABA) system deficits are integral to the pathophysiologic development of fragile X syndrome (FXS). Ganaxolone, a GABAA receptor positive allosteric modulator, is hypothesized to improve symptoms such as anxiety, hyperactivity, and attention deficits in children with FXS.MethodsThis study was a randomized, double-blind, placebo-controlled, crossover trial of ganaxolone in children with FXS, aged 6-17 years.ResultsSixty-one participants were assessed for eligibility, and 59 were randomized to the study. Fifty-five participants completed at least the first arm and were included in the intention-to-treat analysis; 51 participants completed both treatment arms. There were no statistically significant improvements observed on the primary outcome measure (Clinical Global Impression-Improvement), the key secondary outcome measure (Pediatric Anxiety Rating Scale-R), or any other secondary outcome measures in the overall study population. However, post-hoc analyses revealed positive trends in areas of anxiety, attention, and hyperactivity in participants with higher baseline anxiety and low full-scale IQ scores. No serious adverse events (AEs) occurred, although there was a significant increase in the frequency and severity of AEs related to ganaxolone compared to placebo.ConclusionsWhile ganaxolone was found to be safe, there were no significant improvements in the outcome measures in the overall study population. However, ganaxolone in subgroups of children with FXS, including those with higher anxiety or lower cognitive abilities, might have beneficial effects.Trial registrationClinicalTrials.gov, NCT01725152.

Rationale: Ganaxolone (GNX) is the first synthetic analogue of Allopregnanolone. It prevents seizures through positive allosteric modulation of synaptic and extrasynaptic GABAA receptors, mimicking action of endogenous steroids. The mechanism of action of GNX and sodium valproate are different. Therefore, the two drugs have been combined in our study. Polytherapy (treatment with two or more AEDs) can affect the efficacies in additive, supra-additive (synergistic) or infra-additive manner. Synergistic interactions can be useful because they allow lower doses of each drug to be used, and therefore have the possibility to reduce the side effects. Objective: To evaluate and compare the sedative effect of ganaxolone, sodium valproate and diazepam on thiopentone sodium induced sleeping time in rats. Methods: A total of 30 rats were divided into 5 groups, each containing 6 rats for each sedative model. Group 1 was treated with 40% Hydroxypropyl-β-Cyclodextrin i.p, Group 2,3 received GNX 5mg/kg and 10mg/kg i.p respectively, Group 4 was given SV 200 mg/kg i.p and Group 5 was given Diazepam 2mg/kg. Following the i.p. injection of thiopentone sodium, the rats were placed in individual cages and observed for measurements of sleep latency and sleep duration. The duration of drug-induced sleep was measured as the time from the loss (onset) to the recovery of the righting reflex Results: The mean duration of sleeping time of ganaxolone 5 mg/kg and sodium valproate 200 mg/kg was similar to the standard sedative drug diazepam. There was significant difference in the mean duration of sleeping time between ganaxolone 10mg/kg and diazepam 2 mg/kg implying that sedative property of ganaxolone 10 mg/kg was more. Conclusion: The sedative effect of ganaxolone closely match those of diazepam. Based on this data reported in our study, ganaxolone could be considered a prototypic molecule for a new class of sedative drugs. [ABSTRACT FROM AUTHOR]

North Sea Progressive Myoclonus Epilepsy (NS-PME) is a rare genetic disorder characterized by ataxia, myoclonus and seizures with a progressive course. Although the cause of NS-PME is known, namely a homozygous mutation in the GOSR2 gene (c.430 G>T; p. Gly144Trp), sufficient treatment is lacking. Despite combinations of on average 3–5 anti-seizure medications (ASMs), debilitating myoclonus and seizures persist. Here we aimed to gain insight into the most effective anti-convulsive target in NS-PME by evaluating the individual effects of ASMs in a NS-PME Drosophila model. A previously generated Drosophila model for NS-PME was used displaying progressive heat-sensitive seizures. We used this model to test 1. a first-generation ASM (sodium barbital), 2. common ASMs used in NS-PME (clonazepam, valproic acid, levetiracetam, ethosuximide) and 3. a novel third-generation ASM (ganaxolone) with similar mode of action to sodium barbital. Compounds were administered by adding them to the food in a range of concentrations. After 7 days of treatment, the percentage of heat-induced seizures was determined and compared to non-treated but affected controls. As previously reported in the NS-PME Drosophila model, sodium barbital resulted in significant seizure suppression, with increasing effect at higher dosages. Of the commonly prescribed ASMs, clonazepam and ethosuximide resulted in significant seizure suppression, whereas both valproic acid and levetiracetam did not show any changes in seizures. Interestingly, ganaxolone did result in seizure suppression as well. Of the six drugs tested, three of the four that resulted in seizure suppression (sodium barbital, clonazepam, ganaxolone) are primary known for their direct effect on GABA A receptors. This suggests that GABA A could be a potentially important target in the treatment of NS-PME. Consequently, these findings add rationale to the exploration of the clinical effect of ganaxolone in NS-PME and other progressive myoclonus epilepsies. • Progressive Myoclonus Epilepsies (PME) are notoriously difficult to treat. • This study evaluates ASMs in a validated North Sea-PME (NS-PME) Drosophila model. • GABA A agonists significantly suppress seizures in a NS-PME Drosophila model. • A new GABA A agonist ganaxolone effectively suppresses seizures in NS-PME Drosophila. • Ganaxolone could be a potential new treatment for NS-PME and other PMEs. [ABSTRACT FROM AUTHOR]

RationaleAbnormalities in excitatory/inhibitory neurotransmission are hypothesized to contribute to autism spectrum disorder (ASD) etiology. BTBR T (+) Itpr3 (tf) /J (BTBR), an inbred mouse strain, displays social deficits and repetitive self-grooming, offering face validity to ASD diagnostic symptoms. Reduced GABAergic neurotransmission in BTBR suggests that GABAA receptor positive allosteric modulators (PAMs) could improve ASD-relevant BTBR phenotypes. The neuroactive steroid ganaxolone acts as a PAM, displaying anticonvulsant properties in rodent epilepsy models and an anxiolytic-like profile in the elevated plus-maze.ObjectivesWe evaluated ganaxolone in BTBR and C57BL/6J mice in standardized assays for sociability and repetitive behaviors. Open field and anxiety-related behaviors were tested as internal controls and for comparison with the existing neuroactive steroid literature.ResultsGanaxolone improved aspects of social approach and reciprocal social interactions in BTBR, with no effect on repetitive self-grooming, and no detrimental effects in C57BL/6J. Ganaxolone increased overall exploratory activity in BTBR and C57BL/6J in the open field, social approach, and elevated plus-maze, introducing a confound for the interpretation of social improvements. Allopregnanolone and diazepam similarly increased total entries in the elevated plus-maze, indicating that behavioral activation may be a general property of GABAA receptor PAMs in these strains.ConclusionsGanaxolone shows promise for improving sociability. In addition, ganaxolone, as well as other GABAA receptor PAMs, enhanced overall BTBR activity. The translational implications of specific sociability improvements and nonspecific behavioral activation by ganaxolone in the BTBR model remain to be determined. Future studies to explore whether PAMs provide a novel profile with unique benefits for ASD treatment will be worthwhile.

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., Competing Interests: Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work., (Copyright © 2024, Singhal et al.)

Introduction: Nonsulfated neurosteroids can provide phasic and tonic inhibition through activation of synaptic and extra-synaptic γ-aminobutyric acid (GABA)A receptors, exhibiting a greater potency for the latter. These actions occur by interacting with modulatory sites that are distinct from those bound by benzodiazepines and barbiturates. Ganaxolone (GNX) is a synthetic analog of the endogenous neurosteroid allopregnanolone and a member of a novel class of neuroactive steroids called epalons. Areas covered: The authors review the pharmacology of GNX, summarize the main clinical evidence about its antiseizure efficacy and tolerability, and suggest implications for clinical practice and future research. Expert opinion: The clinical development of GNX is mainly oriented to target unmet needs and focused on status epilepticus and rare genetic epilepsies that have few or no treatment options. The availability of oral and intravenous formulations allows reaching adult and pediatric patients in acute and chronic care settings. Further evidence will complement the understanding of the potentialities of GNX and possibly lead to indications for use in clinical practice. [ABSTRACT FROM AUTHOR]

[Display omitted] • New metabolite 2 of oxandrolone (1) was obtained through biotransformation. • New metabolite 4 of ganaxolone (3) was synthesized through biotransformation. • Derivative 2 showed a potent anti-aromatase activity (IC 50 = 0.6 ± 0.005 μM). • Ganaxolone (1) showed a good aromatase inhibitory activity (IC 50 = 13.76 ± 2.00 μM). • Compounds 1 - 4 were found to be non-cytotoxic to 3T3 cell line. Glomerella fusarioides- mediated structural modifications of steroidal anabolic drug, oxandrolone (1), yielded a new product 17 β ,11 α -dihydroxy-17 α -methylandrosta-2-oxa-4-ene-3-one (2). Similarly, Cunninghamella elegans -catalyzed transformation of a steroidal anti-epileptic drug ganaxolone (3) afforded a new metabolite 14 α -hydroxy-5 α -pregnan-1-ene-3,20-dione (4). Structures of new metabolites 2 and 4 were deduced via 1D-, and 2D-NMR, HREI-, HRFAB-MS, and IR spectroscopic techniques. New derivative 2 showed a remarkable anti-aromatase activity with an IC 50 = 0.6 ± 0.005 μM, when compared to substrate 1 (IC 50 = 0.808 ± 0.07 μM), and standard anti-cancer drug exemestane (IC 50 = 0.232 ± 0.031 μM). Ganaxolone (3) (IC 50 = 13.76 ± 2.00 μM) also showed a good activity against human aromatase enzyme, while its derivative 4 was found to be inactive. Inhibition of aromatase enzyme is a key approach in the treatment of estrogen positive breast cancers. Compounds 1 - 4 were non-cytotoxic to 3T3 cell line (mouse fibroblast). [ABSTRACT FROM AUTHOR]

Repurposing regulatory agency-approved molecules, with proven safety in humans, is an attractive option for developing new treatments for disease. We identified and assessed the efficacy of 3 drugs predicted by an in silico screen as having the potential to treat l -DOPA-induced dyskinesia (LID) in Parkinson's disease. We analysed ∼1.3 million Medline abstracts using natural language processing and ranked 3539 existing drugs based on predicted ability to reduce LID. 3 drugs from the top 5% of the 3539 candidates; lorcaserin, acamprosate and ganaxolone, were prioritized for preclinical testing based on i) having a novel mechanism of action, ii) having not been previously validated for the treatment of LID, iii) being blood-brain-barrier penetrant and orally bioavailable and iv) being clinical trial ready. We assessed the efficacy of acamprosate, ganaxolone and lorcaserin in a rodent model of l -DOPA-induced hyperactivity, with lorcaserin affording a 58% reduction in rotational asymmetry (P < 0.05) compared to vehicle. Acamprosate and ganaxolone failed to demonstrate efficacy. Lorcaserin, a 5HT2C agonist, was then further tested in MPTP lesioned dyskinetic macaques where it afforded an 82% reduction in LID (P < 0.05), unfortunately accompanied by a significant increase in parkinsonian disability. In conclusion, although our data do not support the repurposing of lorcaserin, acamprosate or ganaxolone per se for LID, we demonstrate value of an in silico approach to identify candidate molecules which, in combination with an in vivo screen, can facilitate clinical development decisions. The present study adds to a growing literature in support of this paradigm shifting approach in the repurposing pipeline. • Novel treatments are needed for l -DOPA-induced dyskinesia in Parkinson's disease. • Natural language processing of published abstracts to identify drugs to repurpose. • 5HT2C agonism is a potential novel mechanism to reduce l -DOPA-induced dyskinesia. • Study supports use of in silico methods in identification of drugs to repurpose. [ABSTRACT FROM AUTHOR]

Fragile X syndrome (FXS) is the most common genetic cause of intellectual disability and the most common single-gene cause of autism. It is caused by mutations on the fragile X mental retardation gene (FMR1) and lack of fragile X mental retardation protein, which in turn, leads to decreased inhibition of translation of many synaptic proteins. The metabotropic glutamate receptor (mGluR) hypothesis states that the neurological deficits in individuals with FXS are due mainly to downstream consequences of overstimulation of the mGluR pathway. The main efforts have focused on mGluR5 targeted treatments; however, investigation on the gamma-aminobutyric acid (GABA) system and its potential as a targeted treatment is less emphasized. The fragile X mouse models (Fmr1-knock out) show decreased GABA subunit receptors, decreased synthesis of GABA, increased catabolism of GABA, and overall decreased GABAergic input in many regions of the brain. Consequences of the reduced GABAergic input in FXS include oversensitivity to sensory stimuli, seizures, and anxiety. Deficits in the GABA receptors in different regions of the brain are associated with behavioral and attentional processing deficits linked to anxiety and autistic behaviors. The understanding of the neurobiology of FXS has led to the development of targeted treatments for the core behavioral features of FXS, which include social deficits, inattention, and anxiety. These symptoms are also observed in individuals with autism and other neurodevelopmental disorders, therefore the targeted treatments for FXS are leading the way in the treatment of other neurodevelopmental syndromes and autism. The GABAergic system in FXS represents a target for new treatments. Herein, we discuss the animal and human trials of GABAergic treatment in FXS. Arbaclofen and ganaxolone have been used in individuals with FXS. Other potential GABAergic treatments, such as riluzole, gaboxadol, tiagabine, and vigabatrin, will be also discussed. Further studies are needed to determine the safety and efficacy of GABAergic treatments for FXS.

Alcohol abuse and dependence have a staggering socioeconomic impact, yet current therapeutic strategies are largely inadequate to treat these disorders. Thus, the development of new strategies that can effectively prevent alcohol use disorders (AUDs) is of paramount importance. Currently approved medications attempt to deter alcohol intake by blocking ethanol metabolism or by targeting the neurochemical systems downstream of the cascades leading to craving and dependence. Unfortunately, these medications have provided only limited success as indicated by the continued high rates of alcohol abuse and alcoholism. The lack of currently available effective treatment strategies is highlighted by the urgent call by the NIAAA to find new and paradigm-changing therapeutics to either prevent or treat alcohol-related problems. This mini-review highlights recent findings from 4 laboratories with a focus on compounds that have the potential to be novel therapeutic agents that can be developed for the prevention and/or treatment of AUDs.