Sleep disturbances are prominent across neurodevelopmental disorders (NDDs) and may reflect specific abnormalities in brain development and function. Overnight polysomnography (PSG) allows for detailed investigation of sleep architecture, offering a unique window into neurocircuit function. Analysis of existing pediatric PSGs from clinical studies could enhance the availability of sleep studies in pediatric patients with NDDs towards a better understanding of mechanisms underlying abnormal development in NDDs. Here, we introduce and characterize a retrospective collection of 1527 clinical pediatric overnight PSGs across five different sites. We first developed an automated stager trained on independent pediatric sleep data, which yielded better performance compared to a generic stager trained primarily on adults. Using consistent staging across cohorts, we derived a panel of electroencephalography (EEG) micro-architectural features. This unbiased approach replicated broad trajectories previously described in typically developing sleep architecture. Further, we found sleep architecture disruptions in children with Down's syndrome (DS) that were consistent across independent cohorts. Finally, we built and evaluated a model to predict age from sleep EEG metrics, which recapitulated our previous findings of younger predicted brain age in children with DS. Altogether, by creating a resource pooled from existing clinical data we expanded the available datasets and computational resources to study sleep in pediatric populations, specifically towards a better understanding of sleep in NDDs. This Retrospective Analysis of Sleep in Pediatric cohorts dataset, including staging annotation derived from our automated stager is deposited at https://sleepdata.org/datasets/rasp.Statement of Significance We introduce the Retrospective Analysis of Sleep (RASP) cohorts, a collection of 1527 clinical pediatric overnight polysomnographies that includes typically developing and neurodevelopmental disorder cases. As a first step towards addressing the analytic bottleneck inherent in manual sleep staging, we developed and validated a pediatric-specific sleep stager. Leveraging the retrospective RASP cohort's dataset, we redemonstrated known developmental trajectories in sleep architecture. To summarize changes in brain function reflected in sleep, we developed a model to predict brain age from sleep measures. We recapitulate younger predicted age in RASP Down's syndrome cases. This valuable resource underscores the utility of existing clinical polysomnography studies for studying sleep disturbances in pediatric neurodevelopmental disorders populations.

AbstractObjectiveRett syndrome (RTT) and MECP2 duplication syndrome (MDS) result from under‐ and overexpression of MECP2, respectively. Preclinical studies using genetic‐based treatment showed robust phenotype recovery for both MDS and RTT. However, there is a risk of converting MDS to RTT, or vice versa, if accurate MeCP2 levels are not achieved. The aim of this study was to identify biomarkers distinguishing RTT from MDS.Materials and MethodsWe prospectively enrolled 11 MDS and 6 male RTT like (MRL) individuals for a panel of clinical and neurophysiological assessments over two visits, 8–10 months apart.ResultsWe identified numerous clinical and physiological features as promising biomarkers. MRL individuals exhibited large amplitude whole body tremor, midline stereotypies (vs. hand flapping at sides in MDS), earlier neuromotor regression, and earlier onset but less commonly refractory epilepsy. In the neurophysiological domain, we observed several marked differences in sleep physiology between MDS/MRL and typically developing (TD) individuals including reduced sleeping time, increased delta power during rapid eye movement (REM) sleep, decreased occipital alpha and increased brain‐wide delta power during wakefulness, and reduced spindle density and duration. MRL individuals also had much lower delta power during NREM 2 and 3 stages than the TD group. We found differences in spindle duration in the temporal lobes and spindle amplitude in the frontal lobes between MDS and MRL.DiscussionOur study revealed distinct clinical features of MDS and MRL that can be monitored during a clinical trial and may serve as target engagement, disease progression, or safety biomarkers for interventional studies.

MECP2 Duplication Syndrome, also known as X-linked intellectual developmental disorder Lubs type (MRXSL; MIM: 300260), is a neurodevelopmental disorder caused by copy number gains spanning MECP2. Despite varying genomic rearrangement structures, including duplications and triplications, and a wide range of duplication sizes, no clear correlation exists between DNA rearrangement and clinical features. We had previously demonstrated that up to 38

BACKGROUND:Trofinetide was approved for the treatment of Rett syndrome based on the results of the phase 3, randomized, placebo-controlled, 12-week LAVENDER study. Rett syndrome is a chronic disorder requiring long-term treatment. We report the efficacy and safety results of LILAC, a 40-week, open-label extension study of LAVENDER. METHODS:Females with Rett syndrome aged 5-21 years received open-label treatment with trofinetide for 40 weeks. The primary endpoint was long-term safety of trofinetide; secondary endpoints included the change from baseline at week 40 in the Rett Syndrome Behaviour Questionnaire score and the Clinical Global Impression-Improvement score at week 40. FINDINGS:Overall, 154 participants were enrolled and treated with trofinetide in LILAC. The most common adverse events in LILAC were diarrhea (74.7%), vomiting (28.6%), and COVID-19 (11.0%). Diarrhea was the most common adverse event leading to treatment withdrawal (21.4%). The Rett Syndrome Behaviour Questionnaire mean score (standard error) improvement from the LAVENDER baseline to week 40 in LILAC was -7.3 (1.62) and -7.0 (1.61) for participants treated with trofinetide and placebo in LAVENDER, respectively. Mean Clinical Global Impression-Improvement scores (standard error) at week 40 rated from the LILAC baseline were 3.1 (0.11) and 3.2 (0.14) for participants treated with trofinetide and placebo in LAVENDER, respectively. CONCLUSIONS:Treatment with trofinetide for ≤40 weeks continued to improve symptoms of Rett syndrome. Trofinetide had a similar safety profile in LILAC as in LAVENDER. FUNDING:The study was supported by Acadia Pharmaceuticals Inc. (San Diego, CA, USA). This trial was registered at ClinicalTrials.gov (NCT04279314).

Rett syndrome (RTT) is rare neurodevelopmental disorder caused by mutations in the MECP2 gene that encodes methyl-CpG-binding protein 2 (MeCP2), a DNA-binding protein with roles in epigenetic regulation of gene expression. Functional loss of MeCP2 results in abnormal neuronal maturation and plasticity, characterized by loss of verbal communication and loss of fine and gross motor function, among others. Trofinetide, a synthetic analog of glycine-proline-glutamate, was approved by the US Food and Drug Administration for the treatment of RTT in adult and pediatric patients aged 2 years and older. Here, we present the development of trofinetide from bench research to clinical studies and emphasize how the collaboration between academia, the pharmaceutical industry, and patient advocacy led to the recent approval. The bench-to-bedside development of trofinetide underscores the value of collaboration between these groups in the development and approval of treatments for rare diseases.

BACKGROUND:Trofinetide was approved for the treatment of Rett syndrome (RTT) in patients aged ≥2 years based on the results of the 12-week, randomized, phase 3 LAVENDER study. In LILAC, a 40-week, open-label extension study of LAVENDER, trofinetide continued to improve the symptoms of RTT, with a similar safety profile as LAVENDER. Here, we report long-term safety and efficacy results of LILAC-2, a 32-month, open-label extension study. METHODS:Females aged 5-22 years who completed LILAC were eligible to enter LILAC-2. Safety and tolerability were assessed with the incidence of adverse events (AEs). Efficacy was assessed with Rett Syndrome Behaviour Questionnaire (RSBQ) and Clinical Global Impression-Improvement (CGI-I) scores. Caregiver interviews explored the patient's experience with RTT and the efficacy of trofinetide during study participation. FINDINGS:In total, 77 participants were enrolled in LILAC-2. The most common AEs were diarrhea (53.2%), COVID-19 (27.3%), and vomiting (19.5%). The mean (standard error [SE]) change in RSBQ score from LAVENDER baseline to week 104 of LILAC-2 was -11.8 (2.45). The mean (SE) CGI-I score from LILAC baseline to week 12 of LILAC-2 was 3.1 (0.10). Most caregivers (96%; n = 24/25) were satisfied or very satisfied with the benefits of trofinetide. CONCLUSIONS:Long-term treatment with trofinetide continued to improve RTT symptoms, without new safety concerns. Caregivers reported satisfaction with trofinetide related to improvements that were meaningful for their child and themselves. FUNDING:The study was supported by Acadia Pharmaceuticals (San Diego, CA, USA). This study was registered at ClinicalTrials.gov: NCT04776746.

Background/aims We aimed to develop a validated patient-reported Gastrointestinal Health Scale (GHS) specific to MECP2 Duplication Syndrome (MDS) to be used in clinical trials. Methods MDS parents completed a Gastrointestinal Health Questionnaire (GHQ) to investigate the most relevant and important items associated with gastrointestinal problems in MECP2-related disorders. Item reduction was executed according to EORTC guidelines. We performed reliability and validity studies for the finalized scale. Results A total of 106 surveys were eligible for item reduction and validation processes. The initial 55 items were reduced to 38 items based on parent responses, expert opinion, and initial confirmatory factor analysis (CFA). The final MDS-specific GHS included 38 items and 7 factors that underwent further reliability and validity assessments. The power of the study was at least 0.982. The Cronbach’s alphas of the instruments were General Health: 0.799, Eating-Chewing-Swallowing: 0.809, Reflux: 0.794, Motility: 0.762, Mood: 0.906, Medication: 0.595, Parenting: 0.942 and all items together: 0.928. The correlation coefficient between total and individual item scores ranged from 0.215 to 0.730. Because of the ordinal nature of the variables, the diagonal weighted least squares estimation (DWLS) method was used to execute the CFA and Structural Equation Modeling. The GHS had excellent model fit with the acceptable range of fit indices values. Conclusions We developed a parent-reported, reliable, and valid MDS-specific GHS. This scale can be utilized in clinical settings or as an outcome measure in translational and clinical research.

Background: Trofinetide was approved by the US Food and Drug Administration for the treatment of Rett syndrome (RTT) in March 2023. Benefiting the ability to communicate in RTT is often identified as the most important caregiver goal for new therapies. This analysis reports the communication-related end points from the phase 3 LAVENDER study of trofinetide in RTT. Methods: Females with RTT, aged five to 20 years, were randomized 1:1 to trofinetide or placebo for 12 weeks. Secondary efficacy end points related to communication were based on change from baseline to week 12 and included the caregiver-rated Communication and Symbolic Behavior Scales Developmental ProfileTM InfantToddler Checklist (CSBS-DP-IT) Social Composite score (key secondary end point; scores ranged from 0 to 26 [higher scores indicated better communication]) and novel clinician rating scales (0 [normal] to 7 [severe impairment]) measuring the ability to communicate choices nonverbally (RTT-COMC) and verbally (RTT-VCOM). Results: Trofinetide demonstrated a statistically significant difference versus placebo for the CSBS-DP-IT Social Composite score (least squares mean [LSM] difference = 1.0; 95% confidence interval [CI], 0.3 to 1.7; P = 0.0064; Cohen's d effect size = 0.43) and a nominally significant difference for the RTT-COMC (LSM difference: -0.3; 95% CI, -0.6 to -0.0; P = 0.0257; Cohen's d effect size = 0.36). As expected, there was no difference for the RTT-VCOM. Conclusions: Significant treatment benefit for trofinetide versus placebo was observed in scales measuring the ability to communicate. These scales may be appropriate for future clinical studies in RTT and other neurodevelopmental disorders. (c) 2023 The Authors. Published by Elsevier Inc. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Background: Trofinetide significantly improved core symptoms of Rett syndrome (RTT) with an acceptable safety profile in LAVENDER. Here, we report the safety and efficacy results of LILAC and LILAC-2, open-label extension studies of LAVENDER. Methods: Females with RTT, aged 5–21 years, received twice-daily, oral trofinetide in LILAC for 40 weeks. Participants who completed LAVENDER and LILAC continued trofinetide in LILAC-2, a 32-month extension study. Safety assessments included the incidence of adverse events (AEs). Efficacy endpoints included the Rett Syndrome Behaviour Questionnaire (RSBQ) and the Clinical Global Impression–Improvement (CGI-I) scale. Results: Overall, 154 patients were enrolled in LILAC. The most common AEs were diarrhea (74.7%) and vomiting (28.6%). The mean (standard error [SE]) change from the LAVENDER baseline to Week 40 in the LILAC study in RSBQ was -7.3 (1.62) and -7.0 (1.61) for participants treated with trofinetide and placebo in LAVENDER, respectively. Mean (SE) CGI-I scores compared with the LILAC baseline at Week 40 were 3.1 (0.11) and 3.2 (0.14) for patients treated with trofinetide and placebo in LAVENDER, respectively. Similar safety and efficacy trends were observed in LILAC-2. Conclusions: Trofinetide continued to improve symptoms of RTT in LILAC and LILAC-2 with a safety profile consistent with LAVENDER.

To investigate the safety/tolerability and exploratory efficacy of long-term treatment with trofinetide in girls aged 2–4 years with Rett syndrome (RTT).

Rett syndrome (RTT) is a progressive neurodevelopmental disorder, and pathogenic Methyl-CpG-binding Protein 2 (MECP2) variants are identified in >95% of individuals with typical RTT. Most of RTT-causing variants in MECP2 are de novo and usually on the paternally inherited X chromosome. While paternal age has been reported to be associated with increased risk of genetic disorders, it is unknown whether parental age contributes to the risk of the development of RTT. Clinical data including parental age, RTT diagnostic status, and clinical severity are collected from 1226 participants with RTT and confirmed MECP2 variants. Statistical analyses are performed using Student t-test, single factor analysis of variance (ANOVA), and multi-factor regression. No significant difference is observed in parental ages of RTT probands compared to that of the general population. A small increase in parental ages is observed in participants with missense variants compared to those with nonsense variants. When we evaluate the association between clinical severity and parental ages by multiple regression analysis, there is no clear association between clinical severity and parental ages. Advanced parental ages do not appear to be a risk factor for RTT, and do not contribute to the clinical severity in individuals with RTT.

AbstractObjectiveWe aimed to determine the longitudinal distribution of hand function skills in individuals with classic Rett syndrome (RTT), an X‐linked dominant neurodevelopmental disorder, and correlate with MECP2 variants.MethodWe conducted a longitudinal study of 946 girls and young women with typical RTT seen between 2006 and 2021 in the US Natural History Study (NHS) featuring a structured clinical evaluation to assess the level of hand function skills. The specific focus of this study was to assess longitudinal variation of hand skills from age 2 through age 18 years in relation to specific MECP2 variant groups.ResultsFollowing the initial regression period, hand function continues to decline across the age spectrum in individuals with RTT. Specific differences are noted with steeper declines in hand function among those with milder variants (Group A: R133C, R294X, R306C, and C‐terminal truncations) compared with groups composed of individuals with more severe variants.ConclusionsThese temporal variations in hand use represent specific considerations that could influence the design of clinical trials that test therapies aiming to ameliorate specific functional limitations in individuals with RTT. Furthermore, the distinct impact of specific MECP2 variants on clinical severity, especially related to hand use, should be considered in such interventional trials.

Objective: To report communication-related endpoints from the phase 3 LAVENDER study in Rett syndrome (RTT). Background: RTT is a debilitating genetic neurodevelopmental disorder that primarily affects females and lacks an approved treatment. Loss of spoken language is a core feature, and most individuals also have a limited ability to communicate nonverbally. Trofinetide (n=93) demonstrated a clinical benefit over placebo (n=94) on global RTT-related co-primary endpoints in LAVENDER and was generally well tolerated. Design/Methods: Females with RTT, aged 5–20 years, were randomized 1:1 to trofinetide or placebo for 12 weeks. Secondary efficacy endpoints related to verbal and non-verbal communication were adapted for RTT or developed for this study, including the caregiver-rated Communication and Symbolic Behavior Scales Developmental Profile™ Infant-Toddler Checklist-Social (CSBS-DP-IT Social) Composite score (key secondary endpoint; scored 0–26, higher score indicating better ability to communicate) and the novel RTT-specific clinician rating scales (0 [normal] to 7 [severe impairment]) that measure the ability to communicate choices to assess the practical ability to communicate nonverbally (RTT-Clinician Rating of Ability to Communicate Choices [RTT-COMC]) and verbally (RTT-Clinician Rating of Verbal Communication [RTT-VCOM]). Results: Based on the change from baseline at Week 12, trofinetide demonstrated a statistically significant difference versus placebo for the CSBS-DP-IT Social Composite score (mean [SE] −0.1 [0.28] versus −1.1 [0.28]; least squares mean [LSM] difference 1.0; 95% CI: 0.3–1.7; p=0.0064; Cohen's d effect size, 0.43), and nominally significant difference for RTT-COMC (mean [SE] −0.4 [0.12] versus 0.0 [0.10]; LSM difference −0.3; 95% CI: −0.6–0.0; p=0.0257; Cohen's d effect size, 0.36). As expected, no difference was observed for the RTT-VCOM. Conclusions: In the LAVENDER study, differences for trofinetide versus placebo were observed in scales measuring ability to communicate. The communication scales used in this study may be useful in future trials for RTT and other neurodevelopmental disorders. Disclosure: Dr. Neul has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Acadia. Dr. Neul has received personal compensation in the range of $500-$4,999 for serving as a Consultant for GW Pharmaceuticals. Dr. Neul has received personal compensation in the range of $10,000-$49,999 for serving as a Consultant for Signant Health. Dr. Neul has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Analysis Group. Dr. Neul has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Taysha Gene Therapies. Dr. Neul has received personal compensation in the range of $10,000-$49,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Alcyone. Dr. Neul has received personal compensation in the range of $10,000-$49,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Ovid. Dr. Neul has received personal compensation in the range of $5,000-$9,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Roche. Dr. Neul has stock in LizardBio. The institution of Dr. Neul has received research support from NIH. The institution of Dr. Neul has received research support from Acadia. The institution of Dr. Neul has received research support from GW Pharmaceuticals. The institution of Dr. Neul has received research support from International Rett Syndrome Foundation. The institution of Dr. Neul has received research support from Rett Syndrome Research Trust. Dr. Percy has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Acadia Pharmaceuticals. Dr. Percy has received personal compensation in the range of $500-$4,999 for serving as an Editor, Associate Editor, or Editorial Advisory Board Member for IOS Press. The institution of Dr. Percy has received research support from NIH/NICHD. The institution of Dr. Benke has received research support from NIH, RSRT, IRSF and Children's Hospital Colorado. The institution of Dr. Benke has received research support from Acadia, GW, RSRT, Ovid/Takeda, Marinus. The institution of Dr. Benke has received research support from Acadia, CUREGRI, GRINtherapeutics, GW, IRSF, Marinus, Neurogene, Taysha, Ultragenyx and Zogenix/UCB; . The institution of Dr. Berry-Kravis has received research support from NIH. The institution of Dr. Berry-Kravis has received research support from Ovid. The institution of Dr. Berry-Kravis has received research support from Zynerba. The institution of Dr. Berry-Kravis has received research support from Roche. The institution of Dr. Berry-Kravis has received research support from CDC. The institution of Dr. Berry-Kravis has received research support from FRAXA Research Foundation. The institution of Dr. Berry-Kravis has received research support from GeneTx. The institution of Dr. Berry-Kravis has received research support from Angelman Syndrome Foundation. The institution of Dr. Berry-Kravis has received research support from Acadia. The institution of Dr. Berry-Kravis has received research support from GW. The institution of Dr. Berry-Kravis has received research support from Anavex. The institution of Dr. Berry-Kravis has received research support from Rett Syndrome Research Trust. The institution of Dr. Berry-Kravis has received research support from Ultragenyx. The institution of Dr. Berry-Kravis has received research support from Mallinckrodt. The institution of Dr. Berry-Kravis has received research support from Together Strong Foundation. The institution of Dr. Berry-Kravis has received research support from Orphazyme. The institution of Dr. Berry-Kravis has received research support from Ionis. The institution of Dr. Berry-Kravis has received research support from Taysha. The institution of Dr. Berry-Kravis has received research support from Erydel. The institution of Dr. Berry-Kravis has received research support from Tetra. The institution of Dr. Berry-Kravis has received research support from Neuren. The institution of Dr. Berry-Kravis has received research support from FRAXA Research Foundation. Dr. Glaze has nothing to disclose. Dr. Peters has nothing to disclose. Dr. Marsh has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Acadia Pharmaceuticals. The institution of Dr. Marsh has received research support from NIH. The institution of Dr. Marsh has received research support from Rett Syndrome Research Trust. The institution of Dr. Marsh has received research support from International Rett Syndrome Foundation. The institution of Dr. Marsh has received research support from Eagles Autism Challenge. The institution of Dr. Marsh has received research support from LouLou Foundation. The institution of Dr. Marsh has received research support from International CDKL5 Resarch Foundation. The institution of Dr. Marsh has received research support from Acadia Pharmaceuticals. The institution of Dr. Marsh has received research support from Marinus. The institution of Dr. Marsh has received research support from Stoke Therapeutics. The institution of Dr. Marsh has received research support from Takeda Pharmaceuticals. Dr. Marsh has received personal compensation in the range of $500-$4,999 for serving as a Grant Review with NIH. Dr. Marsh has received personal compensation in the range of $5,000-$9,999 for serving as a Expert Witness with Department of Human Services. Ms. Di An has nothing to disclose. Dr. Bishop has received personal compensation for serving as an employee of Acadia Pharmaceuticals. Dr. Bishop has received personal compensation in the range of $10,000-$49,999 for serving as an officer or member of the Board of Directors for DTx Pharma. Dr. Youakim has received personal compensation for serving as an employee of Acadia Pharmaceuticals. Dr. Youakim has stock in Acadia Pharmaceuticals.

The Rett Syndrome Behaviour Questionnaire (RSBQ), which is completed by the caregiver, is one of the most widely used efficacy measures in clinical studies of Rett syndrome (RTT) due to its specificity to the core features of RTT. As healthcare providers participate in routine healthcare assessments of individuals with RTT in clinical practice, there is a need for these providers to understand the psychometric properties of the RSBQ and how it relates to the core clinical features of RTT. Here, we describe the characteristics of the RSBQ, review the literature on its validity and reliability as well as its performance in a phase 2 study and the recent phase 3 LAVENDER study. The RSBQ was first shown to discriminate RTT from other intellectual disorders with good inter-rater and test–retest reliability scores. It was subsequently validated as an appropriate instrument for measuring behavior in females with RTT and adopted as a clinical trial outcome. In LAVENDER, the FDA-approved drug trofinetide significantly improved the RSBQ total score over placebo in girls and women with RTT and change from baseline for all RSBQ subscores were directionally in favor of trofinetide. The change in RSBQ was aligned with the Clinical Global Impression-Improvement scale, suggesting that improvement in behavioral components may be related to overall clinical status. Given its validity and ubiquity in RTT clinical studies, it is important that the interplay of the domains and the psychometric profile of the RSBQ are understood.

Rett syndrome is a rare, genetic neurodevelopmental disorder. Trofinetide is a synthetic analog of glycine–proline–glutamate, the N-terminal tripeptide of the insulin-like growth factor 1 protein, and has demonstrated clinical benefit in phase 2 studies in Rett syndrome. In this phase 3 study ( https://clinicaltrials.gov identifier NCT04181723 ), females with Rett syndrome received twice-daily oral trofinetide ( n = 93) or placebo ( n = 94) for 12 weeks. For the coprimary efficacy endpoints, least squares mean (LSM) change from baseline to week 12 in the Rett Syndrome Behaviour Questionnaire for trofinetide versus placebo was −4.9 versus −1.7 ( P = 0.0175; Cohen’s d effect size, 0.37), and LSM Clinical Global Impression–Improvement at week 12 was 3.5 versus 3.8 ( P = 0.0030; effect size, 0.47). For the key secondary efficacy endpoint, LSM change from baseline to week 12 in the Communication and Symbolic Behavior Scales Developmental Profile Infant–Toddler Checklist Social Composite score was −0.1 versus −1.1 ( P = 0.0064; effect size, 0.43). Common treatment-emergent adverse events included diarrhea (80.6% for trofinetide versus 19.1% for placebo), which was mostly mild to moderate in severity. Significant improvement for trofinetide compared with placebo was observed for the coprimary efficacy endpoints, suggesting that trofinetide provides benefit in treating the core symptoms of Rett syndrome.