L-serine treatment in patients with GRIN-related encephalopathy: a phase 2A, non-randomized study

Current and Emerging Precision Therapies for Developmental and Epileptic Encephalopathies

Developmental and epileptic encephalopathies (DEEs) are severe neurological disorders characterized by childhood-onset seizures and significant developmental impairments. Seizures are often refractory to treatment with traditional antiseizure medications, which fail to address the underlying genetic and molecular mechanisms. This comprehensive review explores the evolving landscape of precision therapeutics for DEEs, focusing on mechanism-driven interventions across key pathophysiologic categories. Targeted approaches for channelopathies include antisense oligonucleotides and gene therapies, such as zorevunersen and ETX101 for SCN1A-related Dravet syndrome, alongside novel small molecules for other ion channel disorders. Advances in targeting neurotransmitter receptor dysfunctions, including γ-aminobutyric acid and glutamate receptor variants, highlight the use of modulators such as gaboxadol, radiprodil, and l-serine, alongside emerging gene therapies. For synaptic dysfunctions, innovative treatments such as chemical chaperones for STXBP1-related disorders and Ras-Raf-MEK-ERK inhibitors for SYNGAP1 pathologies are discussed. The review also examines precision interventions targeting cellular signaling pathways in tuberous sclerosis complex, epigenetic regulation in Rett syndrome, and metabolic interventions like ketogenic diets and targeted supplementation for specific genetic etiologies. Additionally, the importance of enhancing access to genetic testing, conducting robust natural history studies, and employing innovative clinical trial designs is emphasized. Future directions focus on addressing the challenges in developing and implementing gene-based therapies, integrating systems biology, leveraging artificial intelligence for data analysis, and fostering collaboration among stakeholders. The rapidly advancing field of precision therapeutics for DEEs holds promise to improve outcomes through tailored, equitable, and patient-centered care.

Precision therapies for genetic epilepsies in 2025: Promises and pitfalls

By targeting the underlying etiology, precision therapies offer an exciting paradigm shift to improve the stagnant outcomes of drug-resistant epilepsies, including developmental and epileptic encephalopathies. Unlike conventional antiseizure medications (ASMs) which only treat the symptoms (seizures) but have no effect on the underlying disease, precision therapies have the potential to suppress not only the seizures but also disabling comorbidities, including cognitive and behavioral abnormalities, which share the same causative mechanisms. Monogenic epilepsies are an attractive target for precision therapies because of their well-defined molecular mechanisms which can be tested in vitro and can be counteracted by specific drugs. Unfortunately, however, for the vast majority of proposed precision therapies, the evidence for their clinical efficacy is either non-existent or limited to uncontrolled observational accounts. Everolimus is the sole precision therapy with a seizure-related indication with class I evidence of efficacy, highlighting the practical and ethical challenges in obtaining high-level evidence. Here, we review the evidence landscape for candidate precision therapies, including repurposed and innovative treatments currently in development, discuss lessons learned from their use, and highlight strategies to improve their application and evaluation in the clinical setting. PLAIN LANGUAGE SUMMARY: Precision therapies offer a new approach to treat drug-resistant monogenic epilepsies, that is, epilepsies caused by a defect in a single gene. Unlike traditional antiseizure medications, precision therapies target the cause of the disease and have the potential to improve not only seizure control but also concomitant conditions such as cognitive and behavioral disorders. To date, the evidence derived from the clinical use of most proposed precision therapies is limited. This review explores current evidence and strategies to advance their development.

Single Amino Acid Supplementation in Inherited Metabolic Disorders: An Evidence-Based Review of Interventions

BACKGROUND/OBJECTIVES

Inherited metabolic disorders (IMDs) are a group of genetic conditions affecting metabolic pathways. The treatment of some IMDs requires the dietary restriction of specific amino acids. IMDs may also necessitate the supplementation of one or more amino acids due to factors such as reduced dietary intake, impaired synthesis, defective transport or absorption, or increased utilization. This literature review aims to evaluate the most recent evidence regarding amino acid supplementation in IMDs, considering not only the prevention of amino acid deficiency and toxic accumulation but also the competition with other toxic metabolites.

METHODS

A systematic search strategy was developed and applied to PubMed/Medline and Scopus databases to identify relevant studies. Amino acids were categorized into six groups: branched-chain amino acids, aromatic amino acids, sulfur amino acids, urea cycle amino acids, other essential amino acids, and other non-essential amino acids.

RESULTS

A total of 24 rare IMDs were evaluated. A final number of 99 selected articles were assessed based on the Oxford Centre for Evidence-Based Medicine 2011 Levels of Evidence. Although this work represents a preliminary non-systematic review, it highlights the need for further studies and data collection.

CONCLUSIONS

Future research must establish the plasma amino acid levels that indicate the need for supplementation, specify the appropriate dosages (g/day or mg/kg/day), determine the optimal treatment duration, and, crucially, define the target plasma ranges to be maintained for effective management of IMDs.

International Precision Child Health Partnership (IPCHiP): an initiative to accelerate discovery and improve outcomes in rare pediatric disease

Advances in genomic technologies have revolutionized the diagnosis of rare genetic diseases, leading to the emergence of precision therapies. However, there remains significant effort ahead to ensure the promise of precision medicine translates to improved outcomes. Here, we discuss the challenges in advancing precision child health and highlight how international collaborations such as the International Precision Child Health Partnership, which embed research into clinical care, can maximize benefits for children globally.

Population pharmacokinetic and pharmacodynamic model guided weight-tiered dose of AST-001 in pediatric patients with autism spectrum disorder

AST-001, a novel syrup formulation of L-serine, was developed for the treatment of autism spectrum disorders (ASD) in pediatric patients. This study aimed to establish a pharmacokinetic (PK)-pharmacodynamic (PD) model to elucidate the effect of AST-001 on adaptive behavior in children with ASD. Due to the absence of PK samples in pediatric patients, a previously published population PK model was used to link the PD model by applying an allometric scale to body weight. The time courses of Korean-Vineland Adaptive Behavior Scale-II Adaptive Behavior Composite (K-VABS-II-ABC) scores were best described by an effect compartment model with linear drug effects (Deff, 0.0022 L/μg) and linear progression, where an equilibration half-life to the effect compartment was approximately 15 weeks. Our findings indicated a positive correlation between the baseline K-VABS-II-ABC score (E0, 48.51) and the rate of natural progression (Kprog, 0.015 day-1), suggesting enhanced natural behavioral improvements in patients with better baseline adaptive behavior. Moreover, age was identified as a significant covariate for E0 and was incorporated into the model using a power function. Based on our model, the recommended dosing regimens for phase III trials are 2, 4, 6, 10, and 14 g, administered twice daily for weight ranges of 10-13, 14-20, 21-34, 35-49, and >50 kg, respectively. These doses are expected to significantly improve ASD symptoms. This study not only proposes an optimized dosing strategy for AST-001 but also provides valuable insights into the PK-PD relationship in pediatric ASD treatment.

Advances and challenges in serine in the central nervous system: physicochemistry, physiology, and pharmacology

Neurological disorders are the primary cause of human disability and mortality globally, however, current medications slightly alleviate some symptoms of degenerative diseases. Serine is an important amino acid for the brain function and involved in a variety of biosynthetic pathways and signal transduction processes. The imbalance of serine metabolism is associated with neurodegeneration, including neuroinflammation, oxidative stress and apoptosis. Altered activities of serine metabolizing enzymes and accumulation of serine metabolites affect the survival and function of nerve cells. Abnormal serine levels are observed in animal models with neurological diseases, but not all human studies, therefore, the maintenance of serine homeostasis is a potentially therapeutic strategy for neurological disorders. To date, physiological and pharmacological roles of serine in neurological diseases have not been systemically recapitulated, and the association between serine and neurological diseases is controversial. In this review, we summarize physicochemical properties of serine, biological processes of serine in the brain (source, biotransformation, and transport), and the application of serine in neurological diseases including Alzheimer's disease, schizophrenia, and depression. Here, we highlight physicochemistry, physiology, pharmacology, and therapeutic potentials of serine in the prevention and treatment of neurological dysfunction. Our work provides valuable hints for future investigation that will lead to a comprehensive understanding of serine and its metabolism in cellular physiology and pharmacology. Although broad by necessity, the review helps researchers to understand great potentials of serine in the prevention and treatment of neurological dysfunction.

Developmental and epileptic encephalopathies

Developmental and epileptic encephalopathies, the most severe group of epilepsies, are characterized by seizures and frequent epileptiform activity associated with developmental slowing or regression. Onset typically occurs in infancy or childhood and includes many well-defined epilepsy syndromes. Patients have wide-ranging comorbidities including intellectual disability, psychiatric features, such as autism spectrum disorder and behavioural problems, movement and musculoskeletal disorders, gastrointestinal and sleep problems, together with an increased mortality rate. Problems change with age and patients require substantial support throughout life, placing a high psychosocial burden on parents, carers and the community. In many patients, the aetiology can be identified, and a genetic cause is found in >50% of patients using next-generation sequencing technologies. More than 900 genes have been identified as monogenic causes of developmental and epileptic encephalopathies and many cell components and processes have been implicated in their pathophysiology, including ion channels and transporters, synaptic proteins, cell signalling and metabolism and epigenetic regulation. Polygenic risk score analyses have shown that common variants also contribute to phenotypic variability. Holistic management, which encompasses antiseizure therapies and care for multimorbidities, is determined both by epilepsy syndrome and aetiology. Identification of the underlying aetiology enables the development of precision medicines to improve the long-term outcome of patients with these devastating diseases.