Study of Intraventricular Cerliponase Alfa for CLN2 Disease

Role of Biomarkers in Diagnosing Disease, Assessing the Severity and Progression of Disease, and Evaluating the Efficacy of Therapies

This paper reviews biomarkers in lysosomal disease according to their categories and definitions. There are numerous biomarkers in lysosomal diseases. Some are disease or organ-specific, but most are not. Organ-specific biomarkers are especially useful, but most biomarkers help with diagnosis, assessing disease severity, prognosis, and pharmacodynamic response. There are as yet no truly validated biomarkers in lysosomal diseases by the Prentice, Fleming, and DeMets criteria. None so far can serve as surrogate endpoints in clinical trials, or as substitutes for clinically meaningful endpoints that evaluate how patients feel, function, or survive. The US Food and Drug Administration has thus far used surrogate biomarkers to license therapy only for 3 lysosomal diseases-Gaucher disease, Fabry disease, and lysosomal lipase deficiency. The paucity of surrogate biomarkers reflects success in using clinically important endpoints for the licensing of therapies for Pompe disease, mucopolysaccharidosis IVA, VI, and VII, Niemann-Pick type C, and CLN2. In conclusion, biomarkers in lysosomal diseases are best used for diagnosis, patient categorization, pharmacodynamic response, and sometimes for patient prognosis and risk. Thus far, they have been less useful as surrogate biomarkers in pivotal clinical trials.

SUDEP in inherited metabolic epilepsies

Inherited metabolic epilepsies (IMEs) have an increased susceptibility for early mortality, including sudden unexpected death in epilepsy (SUDEP), as they often manifest with frequent drug-resistant seizures, including bilateral tonic-clonic and nocturnal seizures. The metabolic defects inherent to their etiology predispose affected individuals to an additional risk of mortality as they can lead to brain injury, which can induce and be exacerbated by seizures, and to systemic conditions that decrease seizure-cessation and auto-resuscitation processes. The increased risk for SUDEP in IMEs mandates that special emphasis should be given to identifying them early and attempting to achieve seizure control by managing acute metabolic decompensations, anti-seizure medications, and targeted therapies when available. Providing education and support to individuals with IMEs and their families about SUDEP risk factors and prevention strategies is imperative. Despite the increased risk for SUDEP in IMEs, this topic remains understudied. As a proceeding of the 2024 Partners Against Mortality in Epilepsy (PAME) meeting and aiming to increase awareness, this Review describes the pathophysiological and clinical elements related to the heightened risk of SUDEP in IMEs and provides the perspective of a parent of a child with an IME who died from SUDEP. Calling for action, future research on epilepsy-related mortality in IMEs is required. Investigating this field may also yield insights into the general pathomechanisms of SUDEP.

Sinbaglustat ameliorates disease pathology in a murine model of GM1 gangliosidosis without affecting CNS ganglioside levels

Sinbaglustat is a brain-penetrating small molecule that inhibits the non-lysosomal glucocerebrosidase (GBA2) and, with lower potency, glucosylceramide synthase (GCS). Sinbaglustat has passed clinical phase I. Our preclinical study assessed its efficacy in a transgenic mouse model of GM1 gangliosidosis, lacking a functional β-galactosidase enzyme (Glb1-/-). Starting at 4 weeks of age, mice were either treated with a nominal dose of 10 or 300 mg/kg/day of sinbaglustat or remained untreated. Wild-type (WT) mice served as control. Body weight, clinical and neurological signs, and motor function was assessed until 17-18 weeks (4 months) and 30 weeks (7 months) of age when mice were euthanized for ex vivo assessments. In comparison to WT, Glb1-/- mice showed the expected accumulation of GM1 gangliosidosis-related sphingolipids, neuropathology, and behavioral deficits. Both dosages of sinbaglustat left GM1 and lyso GM1 levels in the brain unaffected but delayed the onset of motor impairment and progression of clinical disease in Glb1-/- mice with the higher dose being more efficacious. Histologically and immunohistochemically, both treatment groups of Glb1-/- mice displayed reduced neuronal vacuolation. Only the higher dose of sinbaglustat decreased axonal damage and astrogliosis, which was also associated with a decrease of the axonal/neuronal damage marker plasma neurofilament light at 4 months (17-18 weeks). Both doses of sinbaglustat increased the GBA2 substrate glucosylceramide (GluCer) in the brain, while only the high dose reduced GluCer and other glycosphingolipids (GSLs) in the periphery indicating additional inhibition of GCS. We conclude that sinbaglustat had a therapeutic-like effect in the GM1 gangliosidosis mouse model.

Operational definition of developmental and epileptic encephalopathies to underpin the design of therapeutic trials

Developmental and epileptic encephalopathies (DEEs) are the most severe group of epilepsies, characterized by drug-resistant seizures and developmental slowing or regression. DEEs encompass many epilepsy syndromes, although not all patients with a DEE can be classified into a specific syndrome. Our understanding of the etiologies of DEEs has been revolutionized with next-generation sequencing, with more than 900 genes implicated, in addition to structural causes. It is therefore now possible to consider precision medicine and novel therapeutic approaches for these devastating diseases with trials of repurposed and new drugs, including gene therapies. Trials are being designed to target either DEE diseases more broadly, specific DEE syndromes, or specific genetic DEEs. To serve this purpose, a clear operational definition of DEEs is needed to ensure that appropriate patients are selected for trials with precisely defined, targeted outcome measures. Herein we propose the operational definition of DEEs to set the stage for the development of DEE therapies.

Epilepsy with myoclonic-atonic seizures: an update on genetic causes, nosological limits, and treatment strategies

Epilepsy with myoclonic-atonic seizures is a childhood-onset epilepsy syndrome characterised by a range of seizure types, including myoclonic-atonic, atonic, myoclonic, absence, and generalised tonic-clonic seizures. The causes and outcomes of this syndrome are highly variable, with many uncertainties surrounding its classification and prognosis. Traditional antiseizure medications and the ketogenic diet remain the main treatment options. Although two-thirds of children attain remission from seizures without cognitive or behavioural sequelae, some continue to have drug-resistant seizures, intellectual disability, and behavioural problems. The identification of single-gene causes in a substantial subset of patients highlights the importance of genetic testing for development of personalised treatment strategies. However, diagnostic complexities have hindered the development of trials for new therapies. Better recognition of the distinct features of epilepsy with myoclonic-atonic seizures, combined with advances in molecular genetic testing, will pave the way for more focused clinical research and drug development. Future studies should aim to identify genetic causes and tailor treatment options, offering hope for improved long-term outcomes.

Intravitreal Enzyme Replacement Therapy Slows Retinopathy in Late Infantile Ceroid Lipofuscinosis Type 2

Ceroid lipofuscinosis type 2 (CLN2) is caused by biallelic pathogenic variants in the TPP1 gene, encoding lysosomal tripeptidyl peptidase 1 (TPP1). The classical late-infantile phenotype has an age of onset between 2 and 4 years and is characterized by psychomotor regression, myoclonus, ataxia, blindness, and shortened life expectancy. Vision loss occurs due to retinal degeneration, usually when severe neurological symptoms are already evident.Intracerebroventricular enzyme replacement therapy (ICV-ERT) using recombinant human TPP1 (rhTPP-1) was shown to slow the neurological decline; however, it does not prevent loss of vision. Intravitreal rhTPP-1 (IVT-ERT) was described to halt retinal degeneration in a canine CLN2 model and a compassionate-use study in humans.We report on the clinical and ophthalmological outcome in an early-treated patient homozygous for a pathogenic variant in TPP1 known to be associated with severe CLN2 retinopathy.He was started on ICV-ERT at the age of 40 months and 4 weekly IVT-ERT in one eye at the age of 60 months. The other eye served as untreated control.Baseline best corrected visual acuity (BCVA) was 0.5 with mild bull's eye maculopathy evident in both eyes. After 24 months of IVT-ERT, BCVA in the treated eye was 0.2 with bull's eye maculopathy sparing outer retinal layers, whereas the untreated eye had progressed to endstage retinopathy and BCVA <0.02. No intraocular side effects occurred.Our results provide further evidence that IVT-ERT appears to be safe and markedly delays retinal degeneration preserving visual function and increasing the patient's quality of life, especially if started early.

Drug-device combinations in rare diseases: Challenges and opportunities

Drug-device combinations (DDCs) are therapeutic products that integrate drugs with medical devices to enhance treatment efficacy and/or safety. These combinations hold significant promise for rare diseases, which affect millions of patients globally, by improving drug delivery, targeting specific organs, and reducing side effects. However, the regulatory framework for DDCs remains complex and lacks specific incentives for rare diseases, unlike orphan drugs. This review examines regulatory approaches and case studies of DDCs in rare diseases, and highlights specific challenges and untapped opportunities. Moreover, the publication discusses recommendations to overcome these challenges through tailored policies and incentives to unlock the potential of DDCs in the context of rare diseases.

Magnetic Resonance Imaging as a Readout of CLN5 Gene Therapy Efficacy in Sheep

PURPOSE

Neuronal ceroid lipofuscinoses (NCL; Batten disease) are a group of rare inherited neurodegenerative disorders caused by mutations in one of 13 ceroid lipofuscinosis neuronal (CLN) genes. The diseases share a common set of symptoms, including motor and cognitive dysfunction, progressive loss of vision, and seizure activity. A naturally occurring model of CLN5 NCL exists in New Zealand Borderdale sheep, which exhibit similar clinical disease and post-mortem pathology to the human disease. Recent trials of concurrent intracerebroventricular and intravitreal gene therapy in sheep with CLN5 disease confirmed the therapeutic efficacy of this approach. Given the documented natural history of brain volume changes, detected by MRI, in sheep with CLN5 disease, the current study sought to utilize MRI as both a longitudinal readout and cross-sectional measure of therapeutic efficacy in treated sheep.

METHOD

Sheep treated at a pre-symptomatic timepoint underwent five T1-weighted structural MRI scans between 5 and 18 months of age. Sheep treated at early and advanced symptomatic disease stages underwent a single MRI at 18 months of age. All scans from treated sheep were compared to historical healthy control and affected untreated sheep at each age.

FINDING

Pre-symptomatic treated sheep showed growth in intracranial volume at a comparable rate to healthy control sheep over the course of the study. Whilst grey matter volume decreased and cerebrospinal fluid volume increased in treated sheep, this was to a much smaller degree than in untreated affected sheep. The majority of the cortical regions assessed showed stable volumes over the course of the study, with the notable exception of the cerebellum. Both early and advanced symptomatic treated sheep showed intracranial volumes comparable to untreated affected sheep at 18 months of age. However, when individual tissue types were assessed, grey and white matter were significantly larger, and cerebrospinal fluid was significantly smaller in early symptomatic sheep compared to untreated affected sheep, while the same volumes in advanced symptomatic treated sheep were comparable to untreated affected sheep. Cortical regions assessed showed an age-at-treatment and dose effect.

CONCLUSION

This study has demonstrated that MRI, a clinically relevant outcome measure, can be successfully utilized to assess therapeutic efficacy in a large animal model of CLN5 NCL, both in a longitudinal study and a cross-sectional study when robust natural history data is available for comparison.

Clinical and biochemical footprints of inherited metabolic diseases: Ia. Movement disorders, updated

Movement disorders are a common manifestation of inherited metabolic diseases (IMDs), categorized into hyperkinetic movement disorders, hypokinetic-rigid syndromes, ataxia, and spasticity. We reviewed and updated the list of known metabolic disorders associated with movement disorders, identifying a total of 559 IMDs. We outlined the more common and treatable causes, sorted by the dominant movement disorder phenomenology, and provided a practical clinical approach for suspected IMDs presenting with movement disorders. This work represents an updated catalog in a series of articles aimed at creating and maintaining a comprehensive list of clinical and metabolic differential diagnoses based on system involvement.

Real-world clinical outcomes of patients with CLN2 disease treated with cerliponase alfa

Introduction

This study assessed the real-world effectiveness and safety of the enzyme replacement therapy (ERT), cerliponase alfa, to treat neuronal ceroid lipofuscinosis type 2 (CLN2) disease.

Methods

Data from the DEM-CHILD database were analyzed, comparing patients who initiated ERT outside clinical trials with natural history (NH) controls. Treated patients were matched 1:1 with NH controls on baseline age and combined motor-language (ML) score on the CLN2 clinical rating scale. Rate of ML score decline, time to unreversed 2-point decline or score of 0, and time to unreversed score of 0 were assessed. Safety was assessed in treated patients.

Results

Twenty-four ERT-treated patients were eligible (mean [SD] follow-up: 106.7 [64.1] weeks); 21 matched to a NH control, with baseline mean (SD) age of 4.7 (1.9) years and mean (SD) ML score of 3.9 (1.6) points. ERT-treated patients had reduced likelihood of an unreversed ML 2-point decline or score of 0 (HR 0.08; 95% CI 0.02, 0.28; p < 0.0001), and unreversed ML score of 0 (HR 0.07; 95% CI 0.01, 0.40; p = 0.003) versus NH controls. Mean (SD) rate of ML score decline was 0.46 (0.43) versus 1.88 (1.45) points/48 weeks for ERT-treated and NH groups, respectively (mean difference: 1.42; 95% CI 0.74, 2.10; p = 0.0003). Sixteen patients (67%) had treatment-related adverse events; the most common were pyrexia (50%), vomiting (33%), and nausea (21%). No ERT-treated patients died.

Discussion

Cerliponase alfa for real-world CLN2 disease treatment slowed decline in motor and language function and demonstrated an acceptable safety profile.

Enzyme Replacement Therapy in CLN2-Associated Retinopathy

Neuronal ceroid lipofuscinoses, also known as Batten disease, are comprised of a group of genetically heterogenous neurodegenerative conditions, characterized by dementia, epilepsy, motor deterioration, and blindness. The underlying pathology is a dysregulation of lysosomal catabolic protein metabolism, resulting in an accumulation of lipofuscein-like material within the lysosomes in neuronal tissue, which ultimately leads to atrophy in the central nervous system and in the retina. Ceroid lipofuscinosis type 2 (CLN2) is caused by biallelic pathogenic variants in the TPP1 gene, encoding lysosomal tripeptidyl peptidase 1 (TPP-1). The classic late-infantile phenotype of CLN2 disease has an age of onset between 2 and 4 years and manifests with seizures and speech delay, followed by progressive cognitive and motor decline, vision loss, and early death. Vision loss occurs secondary to retinal degeneration and begins in the perifoveal ellipsoid zone, leading to bull's eye maculopathy, followed by generalized retinal thinning. In 2017, an intracerebroventricular enzyme replacement therapy (ERT) using recombinant human TPP1 (rhTPP1), cerliponase alfa, was approved as a disease-modifying treatment for CLN2 disease. The therapy slows psychomotor decline but fails to prevent loss of vision. In a canine model of CLN2 disease, intravitreal rhTPP1 was shown to halt retinal degeneration. A prospective, interventional, controlled, open-label compassionate-use study evidenced safety of 0.2 mg intravitreal rhTPP1 every 8 weeks in humans and its efficacy in reducing the rate of macular volume loss in patients who were still in the degenerative phase. One ongoing clinical phase I/II study is investigating the safety and efficacy of intravitreal rhTPP1 at 4 weekly intervals over 24 months (NCT05152914); another clinical phase II dose escalation trial is planned. In this review, we summarize the current knowledge on ERT for CLN2 retinopathy, complemented with our own experience from an individual treatment. The treatment now appears to be safe and markedly delays retinal degeneration, thereby preserving visual function and increasing the quality of life of the patient. This could be particularly relevant for those patients who were started on intracerebroventricular ERT early and still have good motor and language function. For this patient population, intravitreal ERT could be a valuable bridging therapy until other therapies such as gene therapy become available.

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.

The use of nanocarriers in treating Batten disease: A systematic review

The neuronal ceroid lipofuscinoses, commonly known as Batten disease, are a group of lysosomal storage disorders affecting children. There is extensive central nervous system and retinal degeneration, resulting in seizures, vision loss and a progressive cognitive and motor decline. Enzyme replacement and gene therapies are being developed, and mRNA and oligonucleotide therapies are more recently being considered. Overcoming the challenges of the blood-brain barrier and blood-ocular barrier is crucial for effectively targeting the brain and eye, whatever the therapeutic approach. Nanoparticles and extracellular vesicles are small carriers that can encapsulate a cargo and pass through these cell barriers. They have been investigated as drug carriers for other pathologies and could be a promising treatment strategy for Batten disease. Their use in gene, enzyme, or mRNA replacement therapy of all lysosomal storage disorders, including Mucopolysaccharidoses, Niemann-Pick diseases, and Fabry disease, is investigated in this systematic review. Different nanocarriers can efficiently target the lysosome and cross the barriers into the brain and eyes. This supports continued exploration of nanocarriers as potential future treatment options for Batten disease.

Neuronal Ceroid Lipofuscinosis-Concepts, Classification, and Avenues for Therapy

Neuronal ceroid lipofuscinosis (NCL) is a group of neurodegenerative lysosomal storage disorders characterized by excessive accumulation of lysosomal lipofuscin. Thirteen subtypes of NCL have been identified, each associated with distinct genes encoding various transmembrane proteins, secretory proteins, or lysosomal enzymes. Clinically, NCL manifests in infants through vision impairment, motor and cognitive dysfunctions, epilepsy, and premature death. The pathological complexity of NCL has hindered the development of effective clinical protocols. Current treatment modalities, including enzyme replacement therapy, pharmacological approaches, gene therapy, and stem cell therapy, have demonstrated limited efficacy. However, emerging evidence suggests a significant relationship between NCL and microglial cells, highlighting the potential of novel microglial cell replacement therapies. This review comprehensively examines the pathogenic genes associated with various NCL subtypes, elucidating their roles, clinical presentations, and corresponding mouse models. Especially, we thoroughly discuss the advances in the clinical study of potential therapeutics, which crucially calls for early diagnosis and treatment more than ever.

Gene therapy ameliorates bowel dysmotility and enteric neuron degeneration and extends survival in lysosomal storage disorder mouse models

Children with neurodegenerative disease often have debilitating gastrointestinal symptoms. We hypothesized that this may be due at least in part to underappreciated degeneration of neurons in the enteric nervous system (ENS), the master regulator of bowel function. To test this hypothesis, we evaluated mouse models of neuronal ceroid lipofuscinosis type 1 and 2 (CLN1 and CLN2 disease, respectively), neurodegenerative lysosomal storage disorders caused by deficiencies in palmitoyl protein thioesterase-1 and tripeptidyl peptidase-1, respectively. Both mouse lines displayed slow bowel transit in vivo that worsened with age. Although the ENS appeared to develop normally in these mice, there was a progressive and profound loss of myenteric plexus neurons accompanied by changes in enteric glia in adult mice. Similar pathology was evident in colon autopsy material from a child with CLN1 disease. Neonatal administration of adeno-associated virus-mediated gene therapy prevented bowel transit defects, ameliorated loss of enteric neurons, and extended survival in mice. Treatment after weaning was less effective than treating neonatally but still extended the lifespan of CLN1 disease mice. These data provide proof-of-principle evidence of ENS degeneration in two lysosomal storage diseases and suggest that gene therapy can ameliorate ENS disease, also improving survival.

Open-label evaluation of oral trehalose in patients with neuronal ceroid lipofuscinoses

The neuronal ceroid lipofuscinoses (NCLs) are incurable pediatric neurodegenerative diseases characterized by accumulation of lysosomal material and dysregulation of autophagy. Given the promising results of treatment with trehalose, an autophagy inducer, in cell and animal models of NCL, we conducted an open-label, non-placebo-controlled, non-randomized 12-month prospective study in NCL patients receiving oral trehalose (4 g/day). All were treated with a commercially available formulation for 6 months, followed by a 6-month washout. The primary endpoint was the presence of severe adverse reactions during treatment; secondary endpoints were clinical changes documented using the validated Unified Batten Disease Rating Scale and the Hamburg scale. Leveraging on our recent multiomic studies identifying convergent biomarkers in NCLs, fluid biomarker changes were taken as additional secondary endpoints. Of the 17 patients enrolled, 11 completed the study. Oral intake of trehalose in NCL patients with different genetic forms and at different disease stages was found to be well tolerated over 6 months. Oral trehalose is associated with subjective benefits reported by caregivers, but not with improvement or worsening on clinical scales. Analysis of potential biomarkers demonstrated significant differences between patients and controls at baseline, but we observed no modifications over time, or correlations with clinical scales and treatment. In our pilot experience in a heterogeneous disease group of NCL, oral trehalose seemed safe for patients. While subjective improvements were reported by caregivers, larger multicenter randomized placebo-controlled studies, and perhaps additional clinical tools covering multiple functions affected by the disease, will be needed to identify possible improvements in clinical scale scores and biomarkers.

Speech, Language and Non-verbal Communication in CLN2 and CLN3 Batten Disease

CLN2 and CLN3 diseases, the most common types of Batten disease (also known as neuronal ceroid lipofuscinosis), are childhood dementias associated with progressive loss of speech, language and feeding skills. Here we delineate speech, language, non-verbal communication and feeding phenotypes in 33 individuals (19 females) with a median age of 9.5 years (range 3-28 years); 16 had CLN2 and 17 CLN3 disease; 8/15 (53%) participants with CLN2 and 8/17 (47%) participants with CLN3 disease had speech and language impairments prior to genetic diagnosis. At the time of study all participants, bar one, had language impairments. The remaining participant with typical language was tested at age 3 years, following pre-symptomatic enzyme replacement therapy (ERT) from age 9 months. CLN2 and CLN3 disease had different profiles. For CLN2 disease, all affected individuals showed language impairment with dysarthria; older individuals with classical disease progressively became non-verbal. For CLN3 disease, the presentation was more heterogeneous. Speech impairment was evident early in the disease course, with dysarthria (13/15, 87%), often manifesting as neurogenic stuttering (5/15, 33%). Participants with CLN2 disease had comparable expressive and receptive language skills (p > 0.99), yet participants with CLN3 disease had stronger expressive language than receptive language skills (p = 0.004). Speech, cognitive and language impairment and adaptive behaviour showed progressive decline in both diseases. Individuals with pre-symptomatic ERT or atypical CLN2 disease were less impaired. Challenging behaviours were common in CLN3 (11/17, 65%), but less frequent in CLN2 (4/16, 25%) disease. Individuals with Batten disease require tailored speech therapy incorporating communication partner training utilising environment adaptations and informal communication behaviours.

Inherited metabolic epilepsies-established diseases, new approaches

Inherited metabolic epilepsies (IMEs) represent the inherited metabolic disorders (IMDs) in which epilepsy is a prevailing component, often determining other neurodevelopmental outcomes associated with the disorder. The different metabolic pathways affected by individual IMEs are the basis of their rarity and heterogeneity. These characteristics make it particularly challenging to establish their targeted therapies, and many of the IMEs are treated nowadays only symptomatically and supportively. However, owing to immense molecular and genetic progress in the last decades, important features of their pathomechanisms have been elucidated. This has led to advancements in the development of novel diagnostic approaches and specific therapies for a considerable number of these unique disorders. This review provides an overview of the broad approach to the diagnosis and management of IMEs, along with their eminent and new individual treatment options, ranging from dietary therapies and vitamins to enzyme and gene replacement therapies. PLAIN LANGUAGE SUMMARY: Inherited metabolic disorders (IMDs) in which epilepsy is a main symptom are considered inherited metabolic epilepsies (IMEs). It is challenging to develop targeted therapies for IMEs since they are rare and individually different in characteristics. Therefore, many of the IMEs are currently treated only symptomatically. However, scientific progress in the last decades led to the creation of specific treatments for many of these unique disorders. This review provides an overview of the approach to the diagnosis and management of IMEs, including the available newer therapeutic modalities.

Peripapillary Retinal Nerve Fiber Layer (pRNFL) Thickness - A Novel Biomarker of Neurodegeneration in Late-Infantile CLN2 Disease

Purpose

To investigate the presence of peripapillary retinal nerve fiber layer (pRNFL) degeneration in patients with late-infantile neuronal ceroid lipofuscinosis type 2 (CLN2) disease and to evaluate the role of optical coherence tomography (OCT) assessed pRNFL thickness as a biomarker for CLN2 disease progression.

Patients and Methods

Forty eyes of 20 patients with genetically and enzymatically confirmed diagnosis of late-infantile CLN2 disease were included in this retrospective cohort study. All patients received 300 mg of intracerebroventricular enzyme replacement treatment (cerliponase alfa) once every two weeks. OCT imaging was performed under general anesthesia using spectral domain OCT (Heidelberg Engineering, Heidelberg, Germany). PRNFL thickness and central retinal thickness (CRT) values were manually confirmed with the Heidelberg Eye Explorer software. Corresponding pediatric data were extracted from the DEM-CHILD database. Spearman correlation coefficient values (rs) were calculated between pRNFL and CRT values, age at examination, the Weill Cornell Late Infantile Neuronal Ceroid Lipofuscinosis (Weill Cornell LINCL) Scale and the Hamburg Motor and Language (HML) Scale.

Results

Fourteen of 20 patients underwent serial examinations resulting in a total of 84 OCT Scans and 42 Weill Cornell LINCL and HML Scale scores. Mean age was 6.90 years and mean follow-up time was 1.38 years. Mean global pRNFL (G-pRNFL) thickness was 77.02 μm presenting a significant decrease compared to normative values from healthy children (106.45 μm; p < 0.0001). G-pRNFL displayed significant correlations towards age at examination (rs = - 0.557, p < 0.01), the Weill Cornell LINCL Scale (rs = 0.849, p < 0.01), and the HML Scale (rs = 0.833, p < 0.01). Repeated measurements indicated decreases in pRNFL thickness over time in most patients.

Conclusion

Patients with late-infantile CLN2 disease exhibit early onset progressive pRNFL loss regardless of outer retinal degeneration, highlighting the potential of pRNFL as an independent ocular biomarker for retinal pathology in late-infantile CLN2 disease.

Adverse Reactions to the Orphan Drug Cerliponase Alfa in the Treatment of Neurolipofuscinosis Type 2 (CLN2)

Background/Objectives: Neuronal Ceroid Lipofuscinosis type 2 is a rare pathology affecting mainly the central nervous system (CNS) and retina, and is caused by variants in the gene encoding the lysosomal enzyme tripeptidyl peptidase 1. Therapy with enzyme replacement through the brain infusion of the orphan drug cerliponase alfa, a recombinant human tripeptidyl peptidase 1 enzyme replacement therapy delivered via intracerebroventricular infusion, has been approved for Neuronal Ceroid Lipofuscinosis type 2 disease. The safety profile of cerliponase alfa has been established based on pre-authorization studies; currently, no post-marketing investigation has been performed to confirm it. Here, a descriptive analysis of real-world spontaneous reporting data of suspected adverse reactions (SARs) to cerliponase alfa in the EudraVigilance database was performed to compile clear information on the safety profile. Methods: Suspected adverse reactions to cerliponase alfa reported in the data system EudraVigilance were analyzed for age, sex of the patient, adverse reactions, and the indication for use. Results: Cases with suspected adverse reactions to cerliponase alfa were found to be more frequent in female patients (58.1%) and in children aged 3-11 years. The most common adverse reactions were, in decreasing order, fever/pyrexia, device-related infection, vomiting, seizures/convulsions, pleocytosis, irritability, ventriculitis, and respiratory disorders. Conclusions: The results confirm the safety profile of cerliponase alfa established with pre-registration clinical studies but suggest the need for further studies to investigate the occurrence of adverse reactions, as possible predictive prognostic markers, in more depth.

Delivery of Neuroregenerative Proteins to the Brain for Treatments of Neurodegenerative Brain Diseases

Neurodegenerative brain diseases such as Alzheimer's disease (AD), multiple sclerosis (MS), and Parkinson's disease (PD) are difficult to treat. Unfortunately, many therapeutic agents for neurodegenerative disease only halt the progression of these diseases and do not reverse neuronal damage. There is a demand for finding solutions to reverse neuronal damage in the central nervous system (CNS) of patients with neurodegenerative brain diseases. Therefore, the purpose of this review is to discuss the potential for therapeutic agents like specific neurotrophic and growth factors in promoting CNS neuroregeneration in brain diseases. We discuss how BDNF, NGF, IGF-1, and LIF could potentially be used for the treatment of brain diseases. The molecule's different mechanisms of action in stimulating neuroregeneration and methods to analyze their efficacy are described. Methods that can be utilized to deliver these proteins to the brain are also discussed.

Psychometric Validation of the CLN2 Quality of Life Questionnaire in Participants with CLN2 Disease Treated with Cerliponase Alfa

OBJECTIVES

This study evaluated the psychometric properties of the ceroid lipofuscinosis type 2 Quality of Life (CLN2 QoL) questionnaire.

METHODS

Data from children with CLN2 disease aged 3-16 years receiving cerliponase alfa in the BMN 190-201 and BMN 190-202 clinical studies, collected via purposive sampling, were used to assess convergent and divergent validity, internal consistency and reliability. The clinically important difference (CID) was estimated with distribution- and anchor-based methods. Descriptive and inferential statistical analyses were conducted using IBM SPSS.

RESULTS

CLN2 QoL data of 22 participants were analysed. Ceiling effects were observed in 22 items (35% threshold); no floor effects were observed. Internal consistency analysis showed good reliability (Cronbach's alpha and Omega reliability >0.7) for four domains at study completion; only one domain had good reliability at baseline. All domains had good test-retest reliability (correlation >0.5) except Feeding With G-Tube and Seizures. Convergent and divergent correlation analysis showed moderate-strong correlations (>0.4) between PedsQL and CLN2 QoL total scores, between the Pediatric Quality of Life Inventory (PedsQL) total score and most CLN2 QoL domains at baseline, and between CLN2 QoL total score and most PedsQL domains at week 97. Known groups validity showed a significant difference in means for the Behaviour domain (p = 0.05) for reasons that could not be clarified. CID was 6.79-12.94 for domains; total score CID was 6.91 using distribution-based and 6.13-13.05 using anchor-based methods.

CONCLUSIONS

This study is the first to validate the CLN2 QoL and to estimate the CID of this instrument in CLN2 patients. Our results show good validity and reliability of this tool.

Enzyme Replacement Therapy for CLN2 Disease: MRI Volumetry Shows Significantly Slower Volume Loss Compared with a Natural History Cohort

BACKGROUND AND PURPOSE

Neuronal ceroid lipofuscinoses are a group of neurodegenerative disorders. Recently, enzyme replacement therapy (ERT) was approved for neuronal ceroid lipofuscinosis type 2 (CLN2), a subtype of neuronal ceroid lipofuscinoses. The aim of this study was to quantify brain volume loss in CLN2 disease in patients on ERT in comparison with a natural history cohort using MRI.

MATERIALS AND METHODS

Nineteen (14 female, 5 male) patients with CLN2 disease at 1 UK center were studied using serial 3D T1-weighted MRI (follow-up time, 1-9 years). Brain segmentation was performed using FreeSurfer. Volume measurements for supratentorial gray and white matter, deep gray matter (basal ganglia/thalami), the lateral ventricles, and cerebellar gray and white matter were recorded. The volume change with time was analyzed using a linear mixed-effects model excluding scans before treatment onset. Comparison was made with a published natural history cohort of 12 patients (8 female, 4 male), which was re-analyzed using the same method.

RESULTS

Brain volume loss of all segmented brain regions was much slower in treated patients compared with the natural history cohort. For example, supratentorial gray matter volume in treated patients decreased by a mean of 3% (SD, 0.74%) (P < .001) annually compared with an annual volume loss of a mean of 16.8% (SD, 1.5%) (P < .001) in the natural history cohort.

CONCLUSIONS

Our treatment cohort showed a significantly slower rate of brain parenchymal volume loss compared with a natural history cohort in several anatomic regions. Our results complement prior clinical data that found a positive response to ERT. We demonstrate that automated MRI volumetry is a sensitive tool to monitor treatment response in children with CLN2 disease.

Cathepsin D inhibition during neuronal differentiation selectively affects individual proteins instead of overall protein turnover

Cathepsin D (CTSD) is a lysosomal aspartic protease and its inherited deficiency causes a severe pediatric neurodegenerative disease called neuronal ceroid lipofuscinosis (NCL) type 10. The lysosomal dysfunction in the affected patients leads to accumulation of undigested lysosomal cargo especially in none-dividing cells, such as neurons, resulting in death shortly after birth. To explore which proteins are mainly affected by the lysosomal dysfunction due to CTSD deficiency, Lund human mesencephalic (LUHMES) cells, capable of inducible dopaminergic neuronal differentiation, were treated with Pepstatin A. This inhibitor of "acidic" aspartic proteases caused accumulation of acidic intracellular vesicles in differentiating LUHMES cells. Pulse-chase experiments involving stable isotope labelling with amino acids in cell culture (SILAC) with subsequent mass-spectrometric protein identification and quantification were performed. By this approach, we studied the degradation and synthesis rates of 695 and 680 proteins during early and late neuronal LUHMES differentiation, respectively. Interestingly, lysosomal bulk proteolysis was not altered upon Pepstatin A treatment. Instead, the protease inhibitor selectively changed the turnover of individual proteins. Especially proteins belonging to the mitochondrial energy supply system were differentially degraded during early and late neuronal differentiation indicating a high energy demand as well as stress level in LUHMES cells treated with Pepstatin A.

Emerging trends in virus and virus-like particle gene therapy delivery to the brain

Recent advances in gene therapy and gene-editing techniques offer the very real potential for successful treatment of neurological diseases. However, drug delivery constraints continue to impede viable therapeutic interventions targeting the brain due to its anatomical complexity and highly restrictive microvasculature that is impervious to many molecules. Realizing the therapeutic potential of gene-based therapies requires robust encapsulation and safe and efficient delivery to the target cells. Although viral vectors have been widely used for targeted delivery of gene-based therapies, drawbacks such as host genome integration, prolonged expression, undesired off-target mutations, and immunogenicity have led to the development of alternative strategies. Engineered virus-like particles (eVLPs) are an emerging, promising platform that can be engineered to achieve neurotropism through pseudotyping. This review outlines strategies to improve eVLP neurotropism for therapeutic brain delivery of gene-editing agents.

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.

Ceroid lipofuscinosis type 2 disease: Effective presymptomatic therapy-Oldest case of a presymptomatic enzyme therapy

Neuronal ceroid lipofuscinosis type 2 (CLN2) disease is a rare, lysosomal storage disorder that causes pediatric onset neurodegenerative disease. It is characterized by mutations in the TPP1 gene. Symptoms begin between 2 and 4 years of age with loss of previously acquired motor, cognitive, and language abilities. Cerliponase alfa, a recombinant human TPP1 enzyme, is the only approved therapy. We report the first presymptomatic cerliponase alfa intraventricular treatment in a familial case of CLN2 related to a classical TPP1 variant. Sister 1 presented with motor, cognitive, and language decline and progressive myoclonic epilepsy since the age of 3 years, evolved with severe diffuse encephalopathy, received no specific treatment, and died at 11 years. Sister 2 had a CLN2 presymptomatic diagnosis and has been treated with cerliponase since she was 12 months old. She is now 6 years 8 months and has no CLN2 symptom except one generalized seizure 1 year ago. No serious adverse event has occurred. Repeated Wechsler Preschool and Primary Scale of Intelligence, Fourth Edition standardized index scores are heterogeneous in the extremely low to low average ranges. Mean length of utterances, a global index of sentence complexity, showed a delay, but a gradual improvement. The reported case enhances the major contribution of presymptomatic diagnosis and significant middle-term treatment benefit for patients with CLN2.

Reduction of neuroinflammation and seizures in a mouse model of CLN1 batten disease using the small molecule enzyme mimetic, N-Tert-butyl hydroxylamine

Infantile neuronal ceroid lipofuscinosis (CLN1 Batten Disease) is a devastating pediatric lysosomal storage disease caused by pathogenic variants in the CLN1 gene, which encodes the depalmitoylation enzyme, palmitoyl-protein thioesterase 1 (PPT1). CLN1 patients present with visual deterioration, psychomotor dysfunction, and recurrent seizures until neurodegeneration results in death, typically before fifteen years of age. Histopathological features of CLN1 include aggregation of lysosomal autofluorescent storage material (AFSM), as well as profound gliosis. The current management of CLN1 is relegated to palliative care. Here, we examine the therapeutic potential of a small molecule PPT1 mimetic, N-tert-butyl hydroxylamine (NtBuHA), in a Cln1-/- mouse model. Treatment with NtBuHA reduced AFSM accumulation both in vitro and in vivo. Importantly, NtBuHA treatment in Cln1-/- mice reduced neuroinflammation, mitigated epileptic episodes, and normalized motor function. Live cell imaging of Cln1-/- primary cortical neurons treated with NtBuHA partially rescued aberrant synaptic calcium dynamics, suggesting a potential mechanism contributing to the therapeutic effects of NtBuHA in vivo. Taken together, our findings provide supporting evidence for NtBuHA as a potential treatment for CLN1 Batten Disease.

Neurological glycogen storage diseases and emerging therapeutics

Glycogen storage diseases (GSDs) comprise a group of inherited metabolic disorders characterized by defects in glycogen metabolism, leading to abnormal glycogen accumulation in multiple tissues, most notably affecting the liver, skeletal muscle, and heart. Recent findings have uncovered the importance of glycogen metabolism in the brain, sustaining a myriad of physiological functions and linking its perturbation to central nervous system (CNS) pathology. This link resulted in classification of neurological-GSDs (n-GSDs), a group of diseases with shared deficits in neurological glycogen metabolism. The n-GSD patients exhibit a spectrum of clinical presentations with common etiology while requiring tailored therapeutic approaches from the traditional GSDs. Recent research has elucidated the genetic and biochemical mechanisms and pathophysiological basis underlying different n-GSDs. Further, the last decade has witnessed some promising developments in novel therapeutic approaches, including enzyme replacement therapy (ERT), substrate reduction therapy (SRT), small molecule drugs, and gene therapy targeting key aspects of glycogen metabolism in specific n-GSDs. This preclinical progress has generated noticeable success in potentially modifying disease course and improving clinical outcomes in patients. Herein, we provide an overview of current perspectives on n-GSDs, emphasizing recent advances in understanding their molecular basis, therapeutic developments, underscore key challenges and the need to deepen our understanding of n-GSDs pathogenesis to develop better therapeutic strategies that could offer improved treatment and sustainable benefits to the patients.

New epilepsy therapies in development

Epilepsy is a common brain disorder, characterized by spontaneous recurrent seizures, with associated neuropsychiatric and cognitive comorbidities and increased mortality. Although people at risk can often be identified, interventions to prevent the development of the disorder are not available. Moreover, in at least 30% of patients, epilepsy cannot be controlled by current antiseizure medications (ASMs). As a result of considerable progress in epilepsy genetics and the development of novel disease models, drug screening technologies and innovative therapeutic modalities over the past 10 years, more than 200 novel epilepsy therapies are currently in the preclinical or clinical pipeline, including many treatments that act by new mechanisms. Assisted by diagnostic and predictive biomarkers, the treatment of epilepsy is undergoing paradigm shifts from symptom-only ASMs to disease prevention, and from broad trial-and-error treatments for seizures in general to mechanism-based treatments for specific epilepsy syndromes. In this Review, we assess recent progress in ASM development and outline future directions for the development of new therapies for the treatment and prevention of epilepsy.

Evolution of Movement Disorders in Patients With CLN2-Batten Disease Treated With Enzyme Replacement Therapy

OBJECTIVES

Neuronal ceroid lipofuscinosis type 2 (CLN2-disease) is an inherited childhood-onset neurodegenerative condition, with classical early features of speech delay, epilepsy, myoclonus, ataxia, and motor regression. This study aimed to better characterize the spectrum of movement disorders in CLN2-disease in a cohort of children receiving enzyme replacement therapy (ERT).

METHODS

A cohort of 18 children attending a single center for treatment with cerliponase alfa ERT was systematically assessed using a standardized structured history and a double-scored, video-recorded examination using the Unified Batten Disease Rating Scale (UBDRS) and Abnormal Involuntary Movement Scale.

RESULTS

Noncanonical movement disorders are common: while ataxia (89%) and myoclonus (83%) were near-universal, spasticity and dystonia were experienced by over half (61% each), with children having a median of 4 distinct movement disorder phenotypes. This progression was stereotyped with initial ataxia/myoclonus, then hyperkinesia/spasticity, and later hypokinesia. ERT slows progression of movement disorders, as measured by the UBDRS physical subscale, with 1.45 points-per-month progression before diagnosis and 0.44 points-per-month while on treatment (p = 0.019).

DISCUSSION

Movement disorders are a core feature of CLN2-disease and follow a typical pattern of progression which is slowed by ERT. Identifying and treating movement disorders should become standard, especially given increased patient survival.

Early Symptoms and Treatment Outcomes in Neuronal Ceroid Lipofuscinosis Type 2: Croatian Experience

BACKGROUND

Late infantile neuronal ceroid lipofuscinosis type 2 (CLN2) is a rare neurodegenerative disease that generally appears in children between 2 and 4 years old, leading to seizures and a progressive loss of language and motor functions. As the disease progresses, affected individuals typically experience blindness and ultimately pass away in late childhood. Treatment with intracerebroventricular cerliponase alfa has been shown to slow the deterioration of motor and language functions compared to the natural progression of the disease. We aim to highlight the early symptoms of CLN2 which help with early diagnosis and timely treatment initiation in children with specific medical indications, as well as identify medical contraindications for enzyme replacement therapy.

METHODS

We describe five Croatian patients and one Bosnia and Herzegovinian patient with CLN2 disease, analyzing the clinical characteristics, neuroimaging findings, electroencephalogram results, genetic analysis, treatment indications and contraindications, and disease progression.

RESULTS

All six patients presented with seizures: focal seizures (n = 1), myoclonic-atonic seizures (n = 1), febrile seizures (n = 2), and tonic-clonic seizures (n = 2), along with language delay (n = 6). Despite this, one patient refused treatment, two were initially included in the clinical trial and then continued treatment, one did not indicate starting treatment, and three continued treatment. One patient, after 4.5 years of treatment, no longer had medical indications for the therapy, which was discontinued. The other two patients who received treatment had a significant slowing of disease progression.

CONCLUSIONS

The early onset of seizures between ages 2 and 4, alongside delayed language development, is a defining characteristic of CLN2 disease. Enzyme replacement therapy using cerliponase alfa represents the initial treatment for neuronal ceroid lipofuscinosis type 2, targeting the underlying cause of the disease. It effectively delays the progression of language and motor decline in patients diagnosed with this condition.

The neuronal ceroid lipofuscinosis type 2 - associated variants: An analysis of alterations in the TPP1 gene and genotype-phenotype correlation in Ukraine

The neuronal ceroid lipofuscinosis type 2 (CLN2) is a heterogeneous group of neurodegenerative lysosomal storage disorders caused by autosomal recessive inheritance of two pathogenic variants in trans in the TPP1 gene. Classical late-infantile CLN2 disease has a very well-defined natural history. However, a small number of patients with TPP1 enzyme deficiency present a later onset or protracted disease course within this group there are phenotypic variants. Our work aimed to identify pathological variants in the TPP1 gene that conditioned the development of CLN2 disease in Ukrainian patients, to compare these variants with those found in patients from other European and non-European regions, and to make genotype-phenotype associations for this disease. The phenotypes and genotypes of the 48 CLN2-affected individuals belonging to 43 families were profiled through clinical data collection, enzyme analysis, and genotyping. In most patients, genotype and phenotype correlation are in keeping with the data of previous studies. The clinical signs of the disease in patients with new, previously undescribed variants, allowed us to augment existing data about genotype-phenotype correlations for CLN2 disease. The combination of genotype and clinical form of the disease demonstrated that predicting the type and clinical course of the disease based on genotype is very complicated. The data we obtained supplements existing information on genotype-phenotypic correlations in this rare disease, which, in turn, lays the foundation for a personalized approach to the management of this disease.

OCT Biomarkers in Ocular CLN2 Disease in Patients Treated With Intraventricular Enzyme Replacement Therapy

Purpose

Bilateral progressive, symmetrical loss of central retinal thickness (CRT) has been described in neuronal ceroid lipofuscinosis type 2 (CLN2) disease. This study details the pattern of morphological changes underlying CRT loss and disease progression in patients receiving intracerebroventricular (ICV) enzyme replacement therapy (ERT) with cerliponase alfa.

Methods

Spectral-domain optical coherence tomography macular cube scans were collected from 16 patients with classic CLN2 disease receiving ICV ERT. Detailed retinal structure analyses were performed on manually segmented horizontal B-scans through the fovea to determine the thickness of six retinal parameters and the extent of ellipsoid zone (EZ) loss.

Results

Anatomical changes primarily occurred in photoreceptor (PR)-related retinal parameters and correlated with ocular disease severity. Retinal degeneration began with initial focal parafoveal EZ discontinuities signaling the onset of rapid PR degeneration in a predictable pattern: parafoveal PR involvement with foveal sparing followed by profound parafoveal and foveal PR loss with additional thinning beyond the central retina. PR degeneration began with outer segment loss and progressed to outer nuclear layer (ONL) involvement. Longitudinal analyses confirmed these observations. The rate of PR loss was fastest at the fovea at ∼58 mm per year and became slower at locations farther away from the fovea.

Conclusions

Retinal degeneration in CLN2 disease is primarily associated with PR loss in a predictable pattern, with EZ disruption signaling early PR stress. CRT, ONL thickness, and PR layer thickness are useful anatomical biomarkers for understanding disease progression and treatment efficacy in CLN2. Studies using en face images will further clarify CLN2-related retinal degeneration.

Intraventricular Cerliponase Alfa Treatment in a Patient with Advanced Neuronal Ceroid Lipofuscinosis Type 2

Neuronal ceroid lipofuscinosis type 2 (CLN2) is an autosomal recessive lysosomal disease caused by decreased activity of the enzyme tripeptidyl peptidase 1 (TPP1) due to pathogenic variants in the TPP1 gene. Cerliponase alfa, a recombinant proenzyme form of TPP1, has shown efficacy in preventing motor and language function decline in early-stage CLN2. However, the safety and effects of this therapy in advanced-stage CLN2 are unclear. We herein report a case of intraventricular cerliponase alfa treatment for over a year in a patient with advanced-stage CLN2. The results suggest the safety and potential efficacy of treatment at an advanced stage of CLN2.

Exploring concurrent validity of the CLN2 Clinical Rating Scale: Comparison to PedsQL using cerliponase alfa clinical trial data

BACKGROUND

The CLN2 Clinical Rating Scale evaluates disease progression in CLN2 disease, an ultra-rare, neurodegenerative disorder with late infantile onset. To validate the Clinical Rating Scale, a comparison with the Pediatric Quality of Life Inventory (PedsQL) was conducted utilising clinical trial data investigating cerliponase alfa use in CLN2 disease.

METHODS

Linear regression and mixed effects models were used to investigate the relationship between the Clinical Rating Scale and PedsQL using open-label, single-arm, phase 1/2 (NCT01907087) and ongoing extension study (NCT02485899) data of 23 children with CLN2 disease treated with cerliponase alfa for ≥96 weeks.

RESULTS

Correlations between the four Clinical Rating Scale domains were low. Linear mixed effects analyses showed significant correlation between PedsQL and Clinical Rating Scale (Total score or motor-language [ML] score adjusted p-values <0.05), driven by the relationship with the PedsQL Physical domain. A statistically significant relationship was identified between the Clinical Rating Scale motor domain and PedsQL (Total score: adjusted p-value = 0.048, parameter estimate [PE] = 8.10; Physical domain score: adjusted p-value = 0.012; PE = 13.79).

CONCLUSIONS

Each domain of the Clinical Rating Scale provides unique information on disease state. Validity of the scale is supported by its relationship with the PedsQL. Among the four domains of the Clinical Rating Scale, motor has the highest correlation to PedsQL, suggesting motor function as a driver of patients' quality of life. The lack of association between the remaining domains of the Clinical Rating Scale and PedsQL suggests that additional disease-specific measures may be needed to fully capture the quality of life impact of CLN2 disease.

TRIAL REGISTRATION

NCT01907087, NCT02485899.

Brain-targeted drug delivery - nanovesicles directed to specific brain cells by brain-targeting ligands

Neurodegenerative diseases are characterized by extensive loss of function or death of brain cells, hampering the life quality of patients. Brain-targeted drug delivery is challenging, with a low success rate this far. Therefore, the application of targeting ligands in drug vehicles, such as lipid-based and polymeric nanoparticles, holds the promise to overcome the blood-brain barrier (BBB) and direct therapies to the brain, in addition to protect their cargo from degradation and metabolization. In this review, we discuss the barriers to brain delivery and the different types of brain-targeting ligands currently in use in brain-targeted nanoparticles, such as peptides, proteins, aptamers, small molecules, and antibodies. Moreover, we present a detailed review of the different targeting ligands used to direct nanoparticles to specific brain cells, like neurons (C4-3 aptamer, neurotensin, Tet-1, RVG, and IKRG peptides), astrocytes (Aquaporin-4, D4, and Bradykinin B2 antibodies), oligodendrocytes (NG-2 antibody and the biotinylated DNA aptamer conjugated to a streptavidin core Myaptavin-3064), microglia (CD11b antibody), neural stem cells (QTRFLLH, VPTQSSG, and NFL-TBS.40-63 peptides), and to endothelial cells of the BBB (transferrin and insulin proteins, and choline). Reports demonstrated enhanced brain-targeted delivery with improved transport to the specific cell type targeted with the conjugation of these ligands to nanoparticles. Hence, this strategy allows the implementation of high-precision medicine, with reduced side effects or unwanted therapy clearance from the body. Nevertheless, the accumulation of some of these nanoparticles in peripheral organs has been reported indicating that there are still factors to be improved to achieve higher levels of brain targeting. This review is a collection of studies exploring targeting ligands for the delivery of nanoparticles to the brain and we highlight the advantages and limitations of this type of approach in precision therapies.

Improving epilepsy diagnosis across the lifespan: approaches and innovations

Epilepsy diagnosis is often delayed or inaccurate, exposing people to ongoing seizures and their substantial consequences until effective treatment is initiated. Important factors contributing to this problem include delayed recognition of seizure symptoms by patients and eyewitnesses; cultural, geographical, and financial barriers to seeking health care; and missed or delayed diagnosis by health-care providers. Epilepsy diagnosis involves several steps. The first step is recognition of epileptic seizures; next is classification of epilepsy type and whether an epilepsy syndrome is present; finally, the underlying epilepsy-associated comorbidities and potential causes must be identified, which differ across the lifespan. Clinical history, elicited from patients and eyewitnesses, is a fundamental component of the diagnostic pathway. Recent technological advances, including smartphone videography and genetic testing, are increasingly used in routine practice. Innovations in technology, such as artificial intelligence, could provide new possibilities for directly and indirectly detecting epilepsy and might make valuable contributions to diagnostic algorithms in the future.

Intravitreal enzyme replacement for inherited retinal diseases

PURPOSE OF REVIEW

This paper provides an update on intravitreal (IVT) enzyme replacement therapy (ERT) in metabolic retinal diseases; particularly neuronal ceroid lipofuscinosis type 2 (CLN2) also known as Batten disease.

RECENT FINDINGS

ERT is being explored in CLN2 related Batten disease, a fatal neurodegenerative condition associated with retinopathy and blindness that is caused by the deficiency of lysosomal enzyme TPP1. Cerliponase alfa, a recombinant human tripeptidyl-peptidase1 (rhTPP1) administered by intraventricular infusions has been demonstrated to slow the rate of neurodegenerative decline but not retinopathy. A preclinical study of IVT rhTPP1 in a CLN2 canine model demonstrated efficacy in preserving retinal function and retinal morphology shown on histology. More recently, intravitreal (IVT) administration of rhTPP1 was reported in a first-in-human compassionate use study. Patients received 12-18 months of 8-weekly IVT ERT (0.2 mg rhTPP-1 in 0.05 ml) in one eye. No significant ocular adverse reactions were reported. Treatment decreased the rate of retinal thinning but modestly.

SUMMARY

The evidence suggests that IVT ERT with rhTPP1 may be a safe and effective treatment for CLN2 retinopathy. However, the optimal dosage and frequency to achieve the best possible outcomes requires further investigation as does patient selection.

Development of an Infantile GM2 Clinical Rating Scale: Remote Assessment of Clinically Meaningful Health-Related Function

GM2 gangliosidoses (GM2) are a group of rare lysosomal storage disorders in which accumulation of GM2 gangliosides results in progressive central nervous system damage. The infantile GM2 phenotype is characterized by delays in milestones by 6 months of age, followed by rapid loss of motor, cognitive, and visual function. Advancements in early diagnosis and pharmacotherapies provide promise for improved outcomes. However, the lack of feasible and clinically meaningful clinical outcome assessments for GM2 poses a challenge to characterizing GM2 natural history and selecting clinical trial endpoints. The purpose of this study was to develop a remotely administered infantile GM2 rating scale to measure health-related function in children with infantile GM2. A 2-phase mixed methods design was employed. In phase 1 of the study, 8 families of children with Infantile GM2 completed a natural history survey and a 1:1 semistructured interview to provide caregiver perspectives on the impacts of GM2 on health-related function. In phase 2 of the study, 8 expert clinicians provided feedback via surveys and participated in videoconference-hosted focus groups to refine scale administration and scoring procedures. These methods guided the development of 16 scale items to assess function in 5 health-related function domains: vision, hand and arm use, communication, gross motor, and feeding. This study used caregiver perspectives and expert clinician feedback to develop a remotely administered clinical outcome assessment of clinically meaningful health-related function in children with infantile GM2. Future studies will further evaluate the feasibility, reliability, and validity of the Infantile GM2 Clinical Rating Scale.

Pharmacodynamic rationale for the choice of antiseizure medications in the paediatric population

In the landscape of paediatric epilepsy treatment, over 20 anti-seizure medications (ASMs) have gained approval from Drug Regulatory Agencies, each delineating clear indications. However, the complexity of managing drug-resistant epilepsy often necessitates the concurrent use of multiple medications. This therapeutic challenge highlights a notable gap: the absence of standardized guidelines, compelling clinicians to rely on empirical clinical experience when selecting combination therapies. This comprehensive review aims to explore current evidence elucidating the preferential utilization of specific ASMs or their combinations, with a primary emphasis on pharmacodynamic considerations. The fundamental objective underlying rational polytherapy is the strategic combination of medications, harnessing diverse mechanisms of action to optimize efficacy while mitigating shared side effects. Moreover, the intricate interplay between epilepsy and comorbidities partly may influence the treatment selection process. Despite advancements, unresolved queries persist, notably concerning the mechanisms underpinning drug resistance and the paradoxical exacerbation of seizures. By synthesizing existing evidence and addressing pertinent unresolved issues, this review aims to contribute to the evolving landscape of paediatric epilepsy treatment strategies, paving the way for more informed and efficacious therapeutic interventions.

First in man study of intravitreal tripeptidyl peptidase 1 for CLN2 retinopathy

BACKGROUND/OBJECTIVES

CLN2 Batten Disease is a fatal neurodegenerative condition of childhood associated with retinal dystrophy and blindness. Intracerebroventricular infusion of rhTPP1 greatly slows the rate of neurodegenerative decline but not retinopathy. Intravitreal rhTPP1 is known to slow retinal degeneration in a canine model of CLN2. We report a first-in-man controlled clinical trial of intravitreal rhTPP1 for CLN2 associated retinal dystrophy.

SUBJECTS/METHODS

8 children aged 5-9 with CLN2 Batten Disease were prospectively enroled. Severely affected patients were preferentially selected, provided that vision was better than no perception of light. Children underwent 8 weekly intravitreal injections of rhTPP1 (0.2 mg in 0.05 ml) into the right eye for 12-18 months. The left eye was untreated and acts as a paired control. The primary outcome was safety based on the clinical detection of complications. A secondary outcome was paracentral macular volume (PMV) measured by spectral domain OCT. Linear regression/paired t tests were used to compare rates of decline.

RESULTS

No severe adverse reactions (uveitis, raised IOP, media opacity) occurred. The mean baseline PMV was 1.28 mm3(right), 1.27 mm3(left). 3 of the youngest patients exhibited bilateral progressive retinal thinning (p < 0.05), whereas retinal volume was stable in the remaining 5 patients. In the 3 patients undergoing retinal degeneration, the rate of PMV loss was slower in the treated vs. untreated eye (p = 0.000042, p = 0.0011, p = 0.00022).

CONCLUSIONS

Intravitreal rhTPP1 appears to be a safe and effective treatment for CLN2 related retinopathy however commencement of treatment early in the course of disease is more likely to be efficacious.

GABAergic interneurons contribute to the fatal seizure phenotype of CLN2 disease mice

GABAergic interneuron deficits have been implicated in the epileptogenesis of multiple neurological diseases. While epileptic seizures are a key clinical hallmark of CLN2 disease, a childhood-onset neurodegenerative lysosomal storage disorder caused by a deficiency of tripeptidyl peptidase 1 (TPP1), the etiology of these seizures remains elusive. Given that Cln2 R207X/R207X mice display fatal spontaneous seizures and an early loss of several cortical interneuron populations, we hypothesized that those two events might be causally related. To address this hypothesis, we first generated an inducible transgenic mouse expressing lysosomal membrane-tethered TPP1 (TPP1LAMP1) on the Cln2 R207X/R207X genetic background to study the cell-autonomous effects of cell-type-specific TPP1 deficiency. We crossed the TPP1LAMP1 mice with Vgat-Cre mice to introduce interneuron-specific TPP1 deficiency. Vgat-Cre ; TPP1LAMP1 mice displayed storage material accumulation in several interneuron populations both in cortex and striatum, and increased susceptibility to die after PTZ-induced seizures. Secondly, to test the role of GABAergic interneuron activity in seizure progression, we selectively activated these cells in Cln2 R207X/R207X mice using Designer Receptor Exclusively Activated by Designer Drugs (DREADDs) in in Vgat-Cre : Cln2 R207X/R207X mice. EEG monitoring revealed that DREADD-mediated activation of interneurons via chronic deschloroclozapine administration accelerated the onset of spontaneous seizures and seizure-associated death in Vgat-Cre : Cln2 R207X/R207X mice, suggesting that modulating interneuron activity can exert influence over epileptiform abnormalities in CLN2 disease. Taken together, these results provide new mechanistic insights into the underlying etiology of seizures and premature death that characterize CLN2 disease.

Classic and Atypical Late Infantile Neuronal Ceroid Lipofuscinosis in Latin America: Clinical and Genetic Aspects, and Treatment Outcome with Cerliponase Alfa

Introduction

Late infantile neuronal ceroid lipofuscinosis type 2 (CLN2), is a neurodegenerative autosomal recessive disease caused by TPP1 gene variants, with a spectrum of classic and atypical phenotypes. The aim of treatment is to slow functional decline as early as possible in an attempt to improve quality of life and survival. This study describes the clinical characteristics as well as the response to treatment with cerliponase alfa.

Materials and methods

A retrospective study was conducted in five Latin-American countries, using clinical records from patients with CLN2. Clinical follow-up and treatment variables are described. A descriptive and bivariate statistical analysis was performed.

Results

A total of 36 patients were observed (range of follow-up of 61-110 weeks post-treatment). At presentation, patients with the classic phenotype (n = 16) exhibited regression in language (90%), while seizures were the predominant symptom (87%) in patients with the atypical phenotype (n = 20). Median age of symptom onset and time to first specialized consultation was 3 (classical) and 7 (atypical) years, while the median time interval between onset of symptoms and treatment initiation was 4 years (classical) and 7.5 (atypical). The most frequent variant was c.827 A > T in 17/72 alleles, followed by c.622C > T in 6/72 alleles. All patients were treated with cerliponase alfa, and either remained functionally stable or had a loss of 1 point on the CLN2 scale, or up to 2 points on the Wells Cornel and Hamburg scales, when compared to pretreatment values.

Discussion and conclusion

This study reports the largest number of patients with CLN2 currently on treatment with cerliponase alfa in the world. Data show a higher frequency of patients with atypical phenotypes and a high allelic proportion of intron variants in our region. There was evidence of long intervals until first specialized consultation, diagnosis, and enzyme replacement therapy. Follow-up after the initiation of cerliponase alfa showed slower progression or stabilization of the disease, associated with adequate clinical outcomes and stable functional scores. These improvements were consistent in both clinical phenotypes.

Treatable inherited metabolic epilepsies

Inherited metabolic epilepsies (IMEs) represent inherited metabolic disorders predominately presenting with seizures. While most IMEs are currently managed with symptomatic and supportive therapies, some are amenable to disorder-specific targeted treatments. In most cases, these treatments are effective only if given in a narrow time window early in the lives of affected patients. Hence, prompt recognition of treatable inherited metabolic epilepsies at an early age and as soon as symptoms appear has paramount importance. Herein, we provide an overview of inherited metabolic epilepsies, which presently have established targeted treatments showing clinical efficacy in reducing seizure burden and improving neurodevelopmental outcomes. These therapeutic modalities range from specific diets, vitamins, and supplementation of organic compounds to synthetic pharmacological agents and novel genetic-based therapies that alter the biochemical pathways of these disorders at the cellular or molecular level, steering them to their normal function.

Dem-Aging: autophagy-related pathologies and the "two faces of dementia"

Neuronal ceroid lipofuscinosis (NCL) is an umbrella term referring to the most frequent childhood-onset neurodegenerative diseases, which are also the main cause of childhood dementia. Although the molecular mechanisms underlying the NCLs remain elusive, evidence is increasingly pointing to shared disease pathways and common clinical features across the disease forms. The characterization of pathological mechanisms, disease modifiers, and biomarkers might facilitate the development of treatment strategies.The DEM-AGING project aims to define molecular signatures in NCL and expedite biomarker discovery with a view to identifying novel targets for monitoring disease status and progression and accelerating clinical trial readiness in this field. In this study, we fused multiomic assessments in established NCL models with similar data on the more common late-onset neurodegenerative conditions in order to test the hypothesis of shared molecular fingerprints critical to the underlying pathological mechanisms. Our aim, ultimately, is to combine data analysis, cell models, and omic strategies in an effort to trace new routes to therapies that might readily be applied in the most common forms of dementia.

Safety and efficacy of cerliponase alfa in children with neuronal ceroid lipofuscinosis type 2 (CLN2 disease): an open-label extension study

BACKGROUND

Cerliponase alfa is a recombinant human tripeptidyl peptidase 1 (TPP1) enzyme replacement therapy for the treatment of neuronal ceroid lipofuscinosis type 2 (CLN2 disease), which is caused by mutations in the TPP1 gene. We aimed to determine the long-term safety and efficacy of intracerebroventricular cerliponase alfa in children with CLN2 disease.

METHODS

This analysis includes cumulative data from a primary 48-week, single-arm, open-label, multicentre, dose-escalation study (NCT01907087) and the 240-week open-label extension with 6-month safety follow-up, conducted at five hospitals in Germany, Italy, the UK, and the USA. Children aged 3-16 years with CLN2 disease confirmed by genetic analysis and enzyme testing were eligible for inclusion. Treatment was intracerebroventricular infusion of 300 mg cerliponase alfa every 2 weeks. Historical controls with untreated CLN2 disease in the DEM-CHILD database were used as a comparator group. The primary efficacy outcome was time to an unreversed 2-point decline or score of 0 in the combined motor and language domains of the CLN2 Clinical Rating Scale. This extension study is registered with ClinicalTrials.gov, NCT02485899, and is complete.

FINDINGS

Between Sept 13, 2013, and Dec 22, 2014, 24 participants were enrolled in the primary study (15 female and 9 male). Of those, 23 participants were enrolled in the extension study, conducted between Feb 2, 2015, and Dec 10, 2020, and received 300 mg cerliponase alfa for a mean of 272·1 (range 162·1-300·1) weeks. 17 participants completed the extension and six discontinued prematurely. Treated patients were significantly less likely than historical untreated controls to have an unreversed 2-point decline or score of 0 in the combined motor and language domains (hazard ratio 0·14, 95% CI 0·06 to 0·33; p<0·0001). All participants experienced at least one adverse event and 21 (88%) experienced a serious adverse event; nine participants experienced intracerebroventricular device-related infections, with nine events in six participants resulting in device replacement. There were no study discontinuations because of an adverse event and no deaths.

INTERPRETATION

Cerliponase alfa over a mean treatment period of more than 5 years was seen to confer a clinically meaningful slowing of decline of motor and language function in children with CLN2 disease. Although our study does not have a contemporaneous control group, the results provide crucial insights into the effects of long-term treatment.

FUNDING

BioMarin Pharmaceutical.