Trial of N-Acetyl-l-Leucine in Niemann-Pick Disease Type C.

BACKGROUND: Niemann-Pick disease type C is a rare lysosomal storage disorder. We evaluated the safety and efficacy of N-acetyl-l-leucine (NALL), an agent that potentially ameliorates lysosomal and metabolic dysfunction, for the treatment of Niemann-Pick disease type C. METHODS: In this double-blind, placebo-controlled, crossover trial, we randomly assigned patients 4 years of age or older with genetically confirmed Niemann-Pick disease type C in a 1:1 ratio to receive NALL for 12 weeks, followed by placebo for 12 weeks, or to receive placebo for 12 weeks, followed by NALL for 12 weeks. NALL or matching placebo was administered orally two to three times per day, with patients 4 to 12 years of age receiving weight-based doses (2 to 4 g per day) and those 13 years of age or older receiving a dose of 4 g per day. The primary end point was the total score on the Scale for the Assessment and Rating of Ataxia (SARA; range, 0 to 40, with lower scores indicating better neurologic status). Secondary end points included scores on the Clinical Global Impression of Improvement, the Spinocerebellar Ataxia Functional Index, and the Modified Disability Rating Scale. Crossover data from the two 12-week periods in each group were included in the comparisons of NALL with placebo. RESULTS: A total of 60 patients 5 to 67 years of age were enrolled. The mean baseline SARA total scores used in the primary analysis were 15.88 before receipt of the first dose of NALL (60 patients) and 15.68 before receipt of the first dose of placebo (59 patients; 1 patient never received placebo). The mean (±SD) change from baseline in the SARA total score was -1.97±2.43 points after 12 weeks of receiving NALL and -0.60±2.39 points after 12 weeks of receiving placebo (least-squares mean difference, -1.28 points; 95% confidence interval, -1.91 to -0.65; P<0.001). The results for the secondary end points were generally supportive of the findings in the primary analysis, but these were not adjusted for multiple comparisons. The incidence of adverse events was similar with NALL and placebo, and no treatment-related serious adverse events occurred. CONCLUSIONS: Among patients with Niemann-Pick disease type C, treatment with NALL for 12 weeks led to better neurologic status than placebo. A longer period is needed to determine the long-term effects of this agent in patients with Niemann-Pick disease type C. (Funded by IntraBio; ClinicalTrials.gov number, NCT05163288; EudraCT number, 2021-005356-10.).

Natural history of valve disease in patients with mucopolysaccharidosis II and the impact of enzyme replacement therapy.

Mucopolysaccharidosis II (MPS II, Hunter syndrome) is a rare, X-linked lysosomal storage disease caused by reduced activity of iduronate-2-sulfatase (I2S), with subsequent cellular accumulation of the glycosaminoglycans (GAGs), heparan sulfate, and dermatan sulfate (DS). DS is a major component of the extracellular matrix of heart valves, which can be affected in MPS II. We investigated the natural history of valve disease in MPS II and the impact of long-term intravenous enzyme replacement therapy (ERT) with recombinant I2S (idursulfase). In total, 604 cardiac examinations were assessed from serial follow-up of 80 male patients (49 neuronopathic). Valve disease was classified according to standard practice from hemodynamic features evident from echocardiography. The natural history group comprised 48 patients (up to 14.8 years of follow-up; median, 2.6 years; 24 patients started ERT during the study); 56 patients were treated (up to 14.2 years of follow-up; median, 6.2 years). Lifetime GAG burden (calculated from urinary GAG measurements) correlated significantly with the degree of valve disease. Onset of moderate-to-severe valve disease was significantly delayed in treated (median age at onset, 29.1 ± 2 [95% CI: 25.2-32.9] years; Kaplan-Meier estimation) versus untreated patients (17.6 ± 1 [95% Cl: 15.8-19.4] years; p < 0.0001). Cox regression modeling found that long-term ERT reduced the probability of developing severe valve disease (χ2, 32.736; significant after 5 years of ERT). Overall, this study found that valve disease severity in MPS II correlates with GAG burden and that progression is delayed by long-term ERT.

Quantitative longitudinal natural history of 8 gangliosidoses-conceptual framework and baseline data of the German 8-in-1 disease registry. A cross-sectional analysis.

PURPOSE: Gangliosidoses are a group of inherited neurogenetic autosomal recessive lysosomal storage disorders usually presenting with progressive macrocephaly, developmental delay, and regression, leading to significant morbidity and premature death. A quantitative definition of the natural history would support and enable clinical development of specific therapies. METHODS: Single disease registry of 8 gangliosidoses (NCT04624789). Cross-sectional analysis of baseline data in N = 26 patients. Primary end point: disease severity assessed by the 8-in-1 score. Secondary end points: first neurologic sign or symptom observed (1) by parents and (2) by physicians, diagnostic delay, as well as phenotypical characterization. Tertiary end points: neurologic outcomes (development, ataxia, dexterity) and disability. RESULTS: The 8-in-1 score quantitatively captured severity of disease. Parents recognized initial manifestations (startle reactions) earlier than physicians (motor developmental delay and hypotonia). Median diagnostic delay was 3.16 (interquartile range 0.69-6.25) years. In total, 8 patients presented with late-infantile phenotypes. CONCLUSION: Data in this registry raise awareness of these rare and fatal conditions to accelerate diagnosis, inform counseling of afflicted families, define quantitative end points for clinical trials, and can serve as historical controls for future therapeutic studies. We provide further insight into the rare late-infantile phenotype for GM2-gangliosidosis. Longitudinal follow up is planned.

A randomized, placebo-controlled clinical trial evaluating olipudase alfa enzyme replacement therapy for chronic acid sphingomyelinase deficiency (ASMD) in adults: One-year results.

PURPOSE: This trial aimed to assess the efficacy and safety of olipudase alfa enzyme replacement therapy for non-central nervous system manifestations of acid sphingomyelinase deficiency (ASMD) in adults. METHODS: A phase 2/3, 52 week, international, double-blind, placebo-controlled trial (ASCEND; NCT02004691/EudraCT 2015-000371-26) enrolled 36 adults with ASMD randomized 1:1 to receive olipudase alfa or placebo intravenously every 2 weeks with intrapatient dose escalation to 3 mg/kg. Primary efficacy endpoints were percent change from baseline to week 52 in percent predicted diffusing capacity of the lung for carbon monoxide and spleen volume (combined with splenomegaly-related score in the United States). Other outcomes included liver volume/function/sphingomyelin content, pulmonary imaging/function, platelet levels, lipid profiles, and pharmacodynamics. RESULTS: Least square mean percent change from baseline to week 52 favored olipudase alfa over placebo for percent predicted diffusing capacity of the lung for carbon monoxide (22% vs 3.0% increases, P = .0004), spleen volume (39% decrease vs 0.5% increase, P < .0001), and liver volume (28% vs 1.5% decreases, P < .0001). Splenomegaly-related score decreased in both groups (P = .64). Other clinical outcomes improved in the olipudase alfa group compared with the placebo group. There were no treatment-related serious adverse events or adverse event-related discontinuations. Most adverse events were mild. CONCLUSION: Olipudase alfa was well tolerated and associated with significant and comprehensive improvements in disease pathology and clinically relevant endpoints compared with placebo in adults with ASMD.

The Clinical and Molecular Spectrum of GM1 Gangliosidosis.

OBJECTIVE: To evaluate the clinical presentation of patients with GM1 gangliosidosis and to determine whether specific clinical or biochemical signs could lead to a prompt diagnosis. STUDY DESIGN: We retrospectively analyzed clinical, biochemical, and genetic data of 22 patients with GM1 gangliosidosis from 5 metabolic centers in Germany and Austria. RESULTS: Eight patients were classified as infantile, 11 as late-infantile, and 3 as juvenile form. Delay of diagnosis was 6 ± 2.6 months in the infantile, 2.6 ± 3.79 years in the late-infantile, and 14 ± 3.48 years in the juvenile form. Coarse facial features, cherry red spots, and visceromegaly occurred only in patients with the infantile form. Patients with the late-infantile and juvenile forms presented with variable neurologic symptoms. Seventeen patients presented with dystonia and 14 with dysphagia. Laboratory analysis revealed an increased ASAT concentration (13/20), chitotriosidase activity (12/15), and pathologic urinary oligosaccharides (10/19). Genotype analyses revealed 23 causative or likely causative mutations in 19 patients, 7 of them being novel variants. In the majority, a clear genotype-phenotype correlation was found. CONCLUSIONS: Diagnosis of GM1 gangliosidosis often is delayed, especially in patients with milder forms of the disease. GM1 gangliosidosis should be considered in patients with progressive neurodegeneration and spastic-dystonic movement disorders, even in the absence of visceral symptoms or cherry red spots. ASAT serum concentrations and chitotriosidase activity may be of value in screening for GM1 gangliosidosis.

Pharmacokinetics, pharmacodynamics, and safety of moss-aGalactosidase A in patients with Fabry disease.

Moss-aGalactosidase A (moss-aGal) is a moss-derived version of human α-galactosidase developed for enzyme replacement therapy in patients with Fabry disease. It exhibits a homogenous N-glycosylation profile with >90% mannose-terminated glycans. In contrast to mammalian cell produced α-galactosidase, moss-aGal does not rely on mannose-6-phosphate receptor mediated endocytosis but targets the mannose receptor for tissue uptake. We conducted a phase 1 clinical trial with moss-aGal in six patients with confirmed diagnosis of Fabry disease during a 28-day schedule. All patients received a single dose of 0.2 mg/kg moss-aGal by i.v.-infusion. Primary endpoints of the trial were safety and pharmacokinetics; secondary endpoints were pharmacodynamics by analyzing urine and plasma Gb3 and lyso-Gb3 concentrations. In all patients, the administered single dose was well tolerated. No safety issues were observed. Pharmacokinetic data revealed a stable nonlinear profile with a short plasma half-life of moss-aGal of 14 minutes. After one single dose of moss-aGal, urinary Gb3 concentrations decreased up to 23% 7 days and up to 60% 28 days post-dose. Plasma concentrations of lyso-Gb3 decreased by 3.8% and of Gb3 by 11% 28 days post-dose. These data reveal that a single dose of moss-aGal was safe, well tolerated, and led to a prolonged reduction of Gb3 excretion. As previously shown, moss-aGal is taken up via the mannose receptor, which is expressed on macrophages but also on endothelial and kidney cells. Thus, these data indicate that moss-aGal may target kidney cells. After these promising results, phase 2/3 clinical trials are in preparation.

Assessment of the reliability, responsiveness, and meaningfulness of the scale for the assessment and rating of ataxia (SARA) for lysosomal storage disorders.

OBJECTIVE: To evaluate the reliability, responsiveness, and validity of the Scale for the Assessment and Rating of Ataxia (SARA) in patients with lysosomal storage disorders (LSDs) who present with neurological symptoms, and quantify the threshold for a clinically meaningful change. METHODS: We analyzed data from three clinical trial cohorts (IB1001-201, IB1001-202, and IB1001-301) of patients with Niemann-Pick disease type C (NPC) and GM2 Gangliosidoses (Tay-Sachs and Sandhoff disease) comprising 122 patients and 703 visits. Reproducibility was described as re-test reliability between repeat baseline visits or baseline and post-treatment washout visits. Responsiveness was determined in relation to the Investigator's, Caregiver's, and Patient's Clinical Global Impression of Improvement (CGI-I). The CGI-I data was also used to quantify a threshold for a clinically meaningful improvement on the SARA scale. Using a qualitative methods approach, patient/caregiver interviews from the IB1001-301 trial were further used to assess a threshold of meaningful change as well as the breadth of neurological signs and symptoms captured and evaluated by the SARA scale. RESULTS: The Inter-Class Correlation (ICC) was 0.95 or greater for all three trials, indicating a high internal consistency/reliability. The mean change in SARA between repeat baseline and post-treatment washout visit assessments in all trials was -0.05, SD 1.98, i.e., minimal, indicating no significant differences, learning effects or other systematic biases. For the CGI-I responses and change in SARA scores, Area Under the Curve (AUC) values were 0.82, 0.71, and 0.77 for the Investigator's, Caregiver's, and Patient's CGI-I respectively, indicating strong agreement. Further qualitative analyses of the patient/caregiver interviews demonstrated a 1-point or greater change on SARA to be a clinically meaningful improvement which is directly relevant to the patient's everyday functioning and quality of life. Changes captured by the SARA were also paralleled by improvement in a broad range of neurological signs and symptoms and beyond cerebellar ataxia. CONCLUSION: Qualitative and quantitative data demonstrate the reliability and responsiveness of the SARA score as a valid measure of neurological signs and symptoms in LSDs with CNS involvement, such as NPC and GM2 Gangliosidoses. A 1-point change represents a clinically meaningful transition reflecting the gain or loss of complex function.

Growth charts for patients with Sanfilippo syndrome (Mucopolysaccharidosis type III).

BACKGROUND: Mucopolysaccharidosis (MPS) type III (Sanfilippo syndrome) comprises a group of rare, lysosomal storage diseases caused by the deficiency of one of four enzymes involved in the degradation of heparan sulfate. The clinical hallmark of the disease is severe neurological deterioration leading to dementia and death in the second decade of life. Adult MPS patients are generally of short stature. To date there is no clear description of the physical development of MPS III patients. The aim of this study was to document growth reference data for MPS III patients. We collected growth data of 182 German MPS III patients and were able to develop growth charts for this cohort. Growth curves for height, weight, head circumference, and body mass index were calculated and compared to German reference charts. RESULTS: Birth height, weight and head circumference were within the physiological ranges. Both genders were significantly taller than healthy children at 2 years of age, while only male patients were taller at the age of four. Growth velocity decelerated after the ages of 4.5 and 5 years for female and male patients, respectively. Both genders were significantly shorter than the reference group at the age of 17.5 years. Head circumference was larger compared to healthy matched controls within the first 2 years of life and remained enlarged until physical maturity. CONCLUSION: MPS III is a not yet treatable severe neuro-degenerative disease, developing new therapeutic strategies might change the course of the disease significantly. The present charts contribute to the understanding of the natural history of MPS III. Specific growth charts represent an important tool for families and physicians as the expected height at physical maturity can be estimated and therapeutic effects can be monitored.

Retinal and optic nerve degeneration in α-mannosidosis.

BACKGROUND: α-mannosidosis is a rare, autosomal-recessive, lysosomal storage disease caused by a deficient activity of α-mannosidase. Typical symptoms include intellectual, motor and hearing impairment, facial coarsening, and musculoskeletal abnormalities. Ocular pathologies reported previously were mainly opacities of the cornea and lens, strabismus, and ocular motility disorders. However, retinal and optic nerve degeneration have been rarely described. METHODS: We report ocular findings of 32 patients with α-mannosidosis. We particularly concentrated on retinal abnormalities which we supported by posterior segment examination, fundus photography, and Spectral-Domain optical coherence tomography (SD-OCT) imaging. RESULTS: Tapeto-retinal degeneration with bone spicule formations in the peripheral retina or macular changes were seen in three patients (9.4%) on funduscopy; of these, two with optic nerve atrophy. Eight retinal images could be obtained by OCT or fundus photography; of these, six showed thinning of the outer retinal layers on OCT. Overall, optic nerve atrophy was seen in six patients (18.8%); of these, four with partial atrophy. Two patients had partial optic nerve atrophy with no retinal abnormalities on funduscopy. Cataract was seen in two (6.3%), corneal haze also in two patients (6.3%). Six patients (18.8%) had manifest strabismus, four (12.5%) nystagmus, and in five patients (15.6%) impaired smooth pursuit eye movements were seen. CONCLUSION: Ocular pathologies are not exclusively confined to opacities of the cornea and lens or strabismus and ocular motility disorders but tapeto-retinal degeneration and optic nerve atrophy may be a common feature in α-mannosidosis. OCT technology helps detecting early outer retinal thinning which can progress with age and potentially leads to vision loss over time.