Risdiplam in Patients Previously Treated with Other Therapies for Spinal Muscular Atrophy: An Interim Analysis from the JEWELFISH Study

INTRODUCTION: Risdiplam is a survival of motor neuron 2 (SMN2) splicing modifier for the treatment of patients with spinal muscular atrophy (SMA). The JEWELFISH study (NCT03032172) was designed to assess the safety, tolerability, pharmacokinetics (PK), and pharmacodynamics (PD) of risdiplam in previously treated pediatric and adult patients with types 1-3 SMA. Here, an analysis was performed after all patients had received at least 1 year of treatment with risdiplam. METHODS: Patients with a confirmed diagnosis of 5q-autosomal recessive SMA between the ages of 6 months and 60 years were eligible for enrollment. Patients were previously enrolled in the MOONFISH study (NCT02240355) with splicing modifier RG7800 or treated with olesoxime, nusinersen, or onasemnogene abeparvovec. The primary objectives of the JEWELFISH study were to evaluate the safety and tolerability of risdiplam and investigate the PK after 2 years of treatment. RESULTS: A total of 174 patients enrolled: MOONFISH study (n = 13), olesoxime (n = 71 patients), nusinersen (n = 76), onasemnogene abeparvovec (n = 14). Most patients (78%) had three SMN2 copies. The median age and weight of patients at enrollment was 14.0 years (1-60 years) and 39.1 kg (9.2-108.9 kg), respectively. About 63% of patients aged 2-60 years had a baseline total score of less than 10 on the Hammersmith Functional Motor Scale-Expanded and 83% had scoliosis. The most common adverse event (AE) was upper respiratory tract infection and pyrexia (30 patients each; 17%). Pneumonia (four patients; 2%) was the most frequently reported serious AE (SAE). The rates of AEs and SAEs per 100 patient-years were lower in the second 6-month period compared with the first. An increase in SMN protein was observed in blood after risdiplam treatment and was comparable across all ages and body weight quartiles. CONCLUSIONS: The safety and PD of risdiplam in patients who were previously treated were consistent with those of treatment-naïve patients

Two-year efficacy and safety of risdiplam in patients with type 2 or non-ambulant type 3 spinal muscular atrophy (SMA)

Risdiplam is an oral, survival of motor neuron 2 (SMN2) pre-mRNA splicing modifier approved for the treatment of spinal muscular atrophy (SMA). SUNFISH (NCT02908685) Part 2, a Phase 3, randomized, double-blind, placebo-controlled study, investigated the efficacy and safety of risdiplam in type 2 and non‑ambulant type 3 SMA. The primary endpoint was met: a significantly greater change from baseline in 32-item Motor Function Measure (MFM32) total score was observed with risdiplam compared with placebo at month 12. After 12 months, all participants received risdiplam while preserving initial treatment blinding. We report 24-month efficacy and safety results in this population. Month 24 exploratory endpoints included change from baseline in MFM32 and safety. MFM‑derived results were compared with an external comparator. At month 24 of risdiplam treatment, 32% of patients demonstrated improvement (a change of ≥ 3) from baseline in MFM32 total score; 58% showed stabilization (a change of ≥ 0). Compared with an external comparator, a treatment difference of 3.12 (95% confidence interval [CI] 1.67-4.57) in favor of risdiplam was observed in MFM-derived scores. Overall, gains in motor function at month 12 were maintained or improved upon at month 24. In patients initially receiving placebo, MFM32 remained stable compared with baseline (0.31 [95% CI - 0.65 to 1.28]) after 12 months of risdiplam; 16% of patients improved their score and 59% exhibited stabilization. The safety profile after 24 months was consistent with that observed after 12 months. Risdiplam over 24 months resulted in further improvement or stabilization in motor function, confirming the benefit of longer-term treatment

Clinical, pathological and functional characterization of riboflavin-responsive neuropathy.

Brown-Vialetto-Van Laere syndrome represents a phenotypic spectrum of motor, sensory, and cranial nerve neuropathy, often with ataxia, optic atrophy and respiratory problems leading to ventilator-dependence. Loss-of-function mutations in two riboflavin transporter genes, SLC52A2 and SLC52A3, have recently been linked to Brown-Vialetto-Van Laere syndrome. However, the genetic frequency, neuropathology and downstream consequences of riboflavin transporter mutations are unclear. By screening a large cohort of 132 patients with early-onset severe sensory, motor and cranial nerve neuropathy we confirmed the strong genetic link between riboflavin transporter mutations and Brown-Vialetto-Van Laere syndrome, identifying 22 pathogenic mutations in SLC52A2 and SLC52A3, 14 of which were novel. Brain and spinal cord neuropathological examination of two cases with SLC52A3 mutations showed classical symmetrical brainstem lesions resembling pathology seen in mitochondrial disease, including severe neuronal loss in the lower cranial nerve nuclei, anterior horns and corresponding nerves, atrophy of the spinothalamic and spinocerebellar tracts and posterior column-medial lemniscus pathways. Mitochondrial dysfunction has previously been implicated in an array of neurodegenerative disorders. Since riboflavin metabolites are critical components of the mitochondrial electron transport chain, we hypothesized that reduced riboflavin transport would result in impaired mitochondrial activity, and confirmed this using in vitro and in vivo models. Electron transport chain complex I and complex II activity were decreased in SLC52A2 patient fibroblasts, while global knockdown of the single Drosophila melanogaster riboflavin transporter homologue revealed reduced levels of riboflavin, downstream metabolites, and electron transport chain complex I activity. This in turn led to abnormal mitochondrial membrane potential, respiratory chain activity and morphology. Riboflavin transporter knockdown in Drosophila also resulted in severely impaired locomotor activity and reduced lifespan, mirroring patient pathology, and these phenotypes could be partially rescued using a novel esterified derivative of riboflavin. Our findings expand the genetic, clinical and neuropathological features of Brown-Vialetto-Van Laere syndrome, implicate mitochondrial dysfunction as a downstream consequence of riboflavin transporter gene defects, and validate riboflavin esters as a potential therapeutic strategy

Polymyositis without Beneficial Response to Steroid Therapy:Should Miyoshi Myopathy be a Differential Diagnosis?

Patient: Male, 16 Final Diagnosis: Miyoshi myopathy Symptoms: HyperCKemia • myalgia • weakness Medication: — Clinical Procedure: — Specialty: Neurology OBJECTIVE: Rare disease BACKGROUND: Miyoshi myopathy (MM) is an autosomal-recessive muscle disorder caused by mutations in the DYSF gene. Clinical features and histopathological changes in dysferlinopathies may mimic inflammatory myopathies and a high degree of clinical suspicion is required to guide the genetic investigation. CASE REPORT: We report the case of a 16-year-old male who presented with severe bilateral calf pain and elevated CK levels (15 000 IU/l) who was on prolonged steroid therapy prompted by the clinical suspicion of inflammatory myopathy. Three years into his illness, he was referred for neuromuscular evaluation presenting with untreatable muscle pain and progressive weakness. The diagnosis of “refractory polymyositis” was revisited. Targeted exome sequencing revealed homozygous pathogenic mutations in the DYSF gene, confirming a diagnosis of Miyoshi myopathy. CONCLUSIONS: Our case illustrates that severe muscle pain may be the initial feature of Miyoshi myopathy and should be considered in the differential diagnosis of inflammatory myopathies. Although the described patient reported partial clinical improvement in muscle pain, steroid treatment is not an effective therapy for dysferlinopathy patients and it did not prevent disease progression. In addition, we confirm the utility of next-generation sequencing approaches to myopathies, particularly in complex or unusual cases when muscle biopsy is not available

Report on the EUROMAC McArdle Exercise Testing Workshop, Madrid, Spain, 11-12 July 2014

We report the main outcomes of the EUROMAC McArdle Exercise Testing Workshop, held in the Universidad Europea (Madrid, Spain) in 11-12 July 2014Fondo de Investigaciones Sanitarias (FIS) PI12/009143.107 JCR (2015) Q2, 61/192 Clinical Neurology, 103/256 NeurosciencesUE

EUROMAC: A European registry for patients with McArdle disease and other very rare muscle glycogenoses

EUROMAC is a European registry of McArdle Disease patients and other very rare muscle glycogenosis (glycogenosis types 0, IV, VII, IX, X, XIII; phosphoglycerate kinase 1 deficiency and muscle lactate dehydrogenase deficiency) presenting with exercise intolerance as the key symptom. EUROMAC aims to promote awareness and understanding of McArdle disease and related conditions to harmonize standards of diagnosis and care and to promote research. EUROMAC was created and developed by a network of 15 partners from 7 EU countries, Turkey and US. Initially funded by the European Commission's Directorate General for Health and Consumers, the registry is currently supported by a grant received from the Fondo de Investigaciones Sanitarias (PI116/01492). Following informed consent from the participant, data (demographics, main clinical symptoms, comorbidities, age at diagnosis and genetic diagnosis) were uploaded onto a safe, encrypted web-based registry (https://www.registryeuromac.eu/en/). In parallel, education, training and dissemination activities were performed. EUROMAC is the largest international registry for patients with McArdle disease. As of March 2018, 313 patients from 10 different countries were recruited. The first Polish patient diagnosed with McArdle disease followed a EUROMAC teaching course, held in Warsaw. The implementation of the EUROMAC project and the setting-up of an international registry have significantly contributed to the effective dissemination of rare muscle GSDs, raising the awareness of these conditions. Additionally, it provided a unique insight into the co-comorbidities affecting people with McArdle disease that should lead to strategies to reduce and manage them in the future.Sin financiación3.115 JCR (2019) Q3, 76/204 Clinical Neurology1.177 SJR (2019) Q1, 85/378 Neurology (clinical)No data IDR 2019UE

Data from the European registry for patients with McArdle disease and other muscle glycogenoses (EUROMAC)

Background: The European registry for patients with McArdle disease and other muscle glycogenoses (EUROMAC) was launched to register rare muscle glycogenoses in Europe, to facilitate recruitment for research trials and to learn about the phenotypes and disseminate knowledge about the diseases through workshops and websites. A network of twenty full and collaborating partners from eight European countries and the US contributed data on rare muscle glycogenosis in the EUROMAC registry. After approximately 3 years of data collection, the data in the registry was analysed. Results: Of 282 patients with confirmed diagnoses of muscle glycogenosis, 269 had McArdle disease. New phenotypic features of McArdle disease were suggested, including a higher frequency (51.4%) of fixed weakness than reported before, normal CK values in a minority of patients (6.8%), ptosis in 8 patients, body mass index above background population and number of comorbidities with a higher frequency than in the background population (hypothyroidism, coronary heart disease). Conclusions: The EUROMAC project and registry have provided insight into new phenotypic features of McArdle disease and the variety of co-comorbidities affecting people with McArdle disease. This should lead to better management of these disorders in the future, including controlling weight, and preventive screening for thyroid and coronary artery diseases, as well as physical examination with attention on occurrence of ptosis and fixed muscle weakness. Normal serum creatine kinase in a minority of patients stresses the need to not discard a diagnosis of McArdle disease even though creatine kinase is normal and episodes of myoglobinuria are absent.Sin financiación4.123 JCR (2020) Q2, 64/175 Genetics & Heredity1.274 SJR (2020) Q1, 365/2448 Medicine (miscellaneous)No data IDR 2019UE

Is the expression of muscle glycogen phosphorylase tissue-specific? New perspectives on McArdle disease

McArdle disease is a rare glycogen storage disorder with a reported incidence of ∼1:100.000 people. It is caused by recessive mutations in the gene encoding for muscle glycogen phosphorylase (MGP), which prevents the skeletal muscle from metabolizing stored glycogen. Until very recently, MGP expression was thought to be essentially restricted to the skeletal muscle tissue. Yet, we have shown that human T lymphocytes also express MGP, which in turn plays a key role to control the migration and proliferation capacity of these cells. This finding suggests that MGP could play an important role in regulating human immune function. In addition, our group has observed previously unreported co-morbidities in patients with McArdle disease including retinopathy, thyroid disease, neurocognitive symptoms and psychiatric disorders. Here we will report on the expression levels of the three glycogen phosphorylase isoforms (brain, liver and muscle [i.e., MGP]) in human immortalized thyroid follicular epithelial (Nthy-ori-3-1) and retinal pigmented epithelium cells (ARPE-19), and in human microglia and astrocytes. We will also present data showing that the absence of expression MGP in Nthy-ori-3-1 and ARPE-19 modifies its biological functions.Sin financiación3.115 JCR (2019) Q3, 76/204 Clinical Neurology1.177 SJR (2019) Q1, 85/378 Neurology (clinical)No data IDR 2019UE