One-year results of a clinical trial of olipudase alfa enzyme replacement therapy in pediatric patients with acid sphingomyelinase deficiency

Assessment of health state utilities associated with adult and pediatric acid sphingomyelinase deficiency (ASMD)

INTRODUCTION

Acid sphingomyelinase deficiency (ASMD) type B is a rare genetic disorder leading to enlargement of the spleen and liver, pulmonary dysfunction, and other symptoms. Cost-utility analyses are often conducted to quantify the value of new treatments, and these analyses require health state utilities. Therefore, the purpose of this study was to estimate utilities associated with varying levels of severity of adult and pediatric ASMD type B.

METHODS

Seven adult and seven child health state vignettes describing ASMD were developed based on published literature, clinical trial results, and interviews with clinicians, patients with ASMD, and parents of children with ASMD. The health states were valued in time trade-off interviews with adult general population respondents in the UK.

RESULTS

Interviews were completed with 202 participants (50.0% female; mean age = 41.3 years). The health state representing ASMD without impairment had the highest mean utility for both the adult and child health states (0.92/0.94), and severe ASMD had the lowest mean utility (0.33/0.45). Every child health state had a significantly greater utility than the corresponding adult health state. Differences between adult/child paired states ranged from 0.02 to 0.13. Subgroup analyses explored the impact of parenting status on valuation of child health states.

DISCUSSION

Greater severity of ASMD was associated with lower mean utility. Results have implications for valuation of pediatric health states. The resulting utilities may be useful in cost-utility modeling estimating the value of treatment for ASMD.

Acid sphingomyelinase deficiency in France: a retrospective survival study

BACKGROUND

Acid sphingomyelinase deficiency (ASMD) or Niemann-Pick disease types A, A/B, and B is a progressive, life-limiting, autosomal recessive disorder caused by sphingomyelin phosphodiesterase 1 (SMPD1) gene mutations. There is a need to increase the understanding of morbidity and mortality across children to adults diagnosed with ASMD.

METHODS

This observational retrospective survey analysed medical records of patients with ASMD with retrievable data from 27 hospitals in France, diagnosed/followed up between 1st January 1990 and 31st December 2020. Eligible records were abstracted to collect demographic, medical/developmental history, and mortality data. Survival outcomes were estimated from birth until death using Kaplan-Meier survival analyses; standardised mortality ratio (SMR) was also explored.

RESULTS

A total of 118 medical records of patients with ASMD (type B [n = 94], type A [n = 15], and type A/B [n = 9]) were assessed. The majority of patients were males (63.6%); the median [range] age at diagnosis was 8.0 [1.0-18.0] months (type A), 1.0 [0-3] year (type A/B), and 5.5 [0-73] years (type B). Overall, 30 patients were deceased at the study completion date; the median [range] age at death for patients with ASMD type A (n = 14) was 1 [0-3.6] year, type A/B (n = 6) was 8.5 [3.0-30.9] years, and type B (n = 10) was 57.6 [3.4-74.1] years. The median [95% confidence interval (CI)] survival age from birth in patients with ASMD type A and type A/B was 2.0 [1.8-2.7] years and 11.4 [5.5-18.5] years, respectively. Survival analysis in ASMD type B was explored using SMR [95% CI] analysis (3.5 [1.6-5.9]), which showed that age-specific deaths in the ASMD type B population were 3.5 times more frequent than those in the general French population. The causes of death were mostly severe progressive neurodegeneration (type A: 16.7%), cancer (type B: 16.7%), or unspecified (across groups: 33.3%).

CONCLUSIONS

This study illustrated a substantial burden of illness with high mortality rates in patients with ASMD, including adults with ASMD type B, in France.

Natural history of acid sphingomyelinase deficiency among European patients during childhood and adolescence: A retrospective observational study

Acid sphingomyelinase deficiency (ASMD) is a rare, lysosomal storage disease with limited evidence on its natural history. This retrospective, medical record abstraction study aimed to characterize the natural history of ASMD (types B and A/B) during childhood and adolescence. Recruiting sites were European centers (i.e., France, Germany, Italy, and the United Kingdom) from the ASCEND-Peds trial (NCT02292654); these sites were targeted because of the rarity of ASMD and specialized care provided at these centers. The study population comprised ASMD trial patients (before exposure to treatment) and ASMD non-trial participants who were managed at the same trial sites. Overall, 18 patients were included (11 trials; 7 non-trials; median [Q1; Q3] age at ASMD diagnosis: 2.5 [1.0; 4.0] years). Median follow-up duration was 10.0 years. Frequently reported medical conditions were hepatobiliary (17 [94.4%]) and blood and lymphatic system disorders (16 [88.9%]). Adenoidectomy (3 [16.7%]) was the most commonly reported surgical procedure; gastroenteritis (5 [27.8%]) was the most frequently reported infection, and epistaxis (6 [33.3%]) was the most commonly reported bleeding event. Abnormal spleen (16 [88.9%]) and liver (15 [83.3%]) size and respiratory function (8 [44.4%]) were commonly reported during physical examination. Overall, 11 (61.1%) patients were hospitalized; 6 (33.3%) patients had emergency room visits. Findings were consistent with published literature and support the current understanding of natural history of ASMD.

The Liver and Lysosomal Storage Diseases: From Pathophysiology to Clinical Presentation, Diagnostics, and Treatment

The liver, given its role as the central metabolic organ, is involved in many inherited metabolic disorders, including lysosomal storage diseases (LSDs). The aim of this manuscript was to provide a comprehensive overview on liver involvement in LSDs, focusing on clinical manifestation and its pathomechanisms. Gaucher disease, acid sphingomyelinase deficiency, and lysosomal acid lipase deficiency were thoroughly reviewed, with hepatic manifestation being a dominant clinical phenotype. The natural history of liver disease in the above-mentioned lysosomal disorders was delineated. The importance of Niemann-Pick type C disease as a cause of cholestatic jaundice, preceding neurological manifestation, was also highlighted. Diagnostic methods and current therapeutic management of LSDs were also discussed in the context of liver involvement.

Lung Diseases and Rare Disorders: Is It a Lysosomal Storage Disease? Differential Diagnosis, Pathogenetic Mechanisms and Management

Pulmonologists may be involved in managing pulmonary diseases in children with complex clinical pictures without a diagnosis. Moreover, they are routinely involved in the multidisciplinary care of children with rare diseases, at baseline and during follow-up, for lung function monitoring. Lysosomal storage diseases (LSDs) are a group of genetic diseases characterised by a specific lysosomal enzyme deficiency. Despite varying pathogen and organ involvement, they are linked by the pathological accumulation of exceeding substrates, leading to cellular toxicity and subsequent organ damage. Less severe forms of LSDs can manifest during childhood or later in life, sometimes being underdiagnosed. Respiratory impairment may stem from different pathogenetic mechanisms, depending on substrate storage in bones, with skeletal deformity and restrictive pattern, in bronchi, with obstructive pattern, in lung interstitium, with altered alveolar gas exchange, and in muscles, with hypotonia. This narrative review aims to outline different pulmonary clinical findings and a diagnostic approach based on key elements for differential diagnosis in some treatable LSDs like Gaucher disease, Acid Sphingomyelinase deficiency, Pompe disease and Mucopolysaccharidosis. Alongside their respiratory clinical aspects, which might overlap, we will describe radiological findings, lung functional patterns and associated symptoms to guide pediatric pulmonologists in differential diagnosis. The second part of the paper will address follow-up and management specifics. Recent evidence suggests that new therapeutic strategies play a substantial role in preventing lung involvement in early-treated patients and enhancing lung function and radiological signs in others. Timely diagnosis, driven by clinical suspicion and diagnostic workup, can help in treating LSDs effectively.

A retrospective study of morbidity and mortality of chronic acid sphingomyelinase deficiency in Germany

BACKGROUND

Acid sphingomyelinase deficiency (ASMD) is a rare, progressive, potentially fatal lysosomal storage disease that exhibits a broad spectrum of clinical phenotypes. There is a need to expand the knowledge of disease mortality and morbidity in Germany because of limited information on survival analysis in patients with chronic ASMD (type B or type A/B).

METHODS

This observational, multicentre, retrospective cohort study was conducted using medical records of patients with the first symptom onset/diagnosis of ASMD type B or type A/B between 1st January 1990 and 31st July 2021 from four German medical centres. Eligible medical records were abstracted to collect data on demographic characteristics, medical history, hospitalisation, mortality, and causes of death from disease onset to the last follow-up/death. Survival outcomes were estimated using the Kaplan-Meier analysis. Standardised mortality ratio (SMR) was also explored.

RESULTS

This study included 33 chart records of patients with ASMD type B (n = 24) and type A/B (n = 9), with a median (interquartile range [IQR]) age of 8.0 [3.0-20.0] years and 1.0 [1.0-2.0] years, respectively, at diagnosis. The commonly reported manifestations were related to spleen (100.0%), liver (93.9%), and respiratory (77.4%) abnormalities. Nine deaths were reported at a median [IQR] age of 17.0 [5.0-25.0] years, with 66.7% of overall patients deceased at less than 18 years of age; the median [IQR] age at death for patients with ASMD type B (n = 4) and type A/B (n = 5) was 31.0 [11.0-55.0] and 9.0 [4.0-18.0] years, respectively. All deaths were ASMD-related and primarily caused by liver or respiratory failures or severe progressive neurodegeneration (two patients with ASMD type A/B). The median (95% confidence interval [CI]) overall survival age since birth was 45.4 (17.5-65.0) years. Additionally, an SMR [95% CI] analysis (21.6 [9.8-38.0]) showed that age-specific deaths in the ASMD population were 21.6 times more frequent than that in the general German population.

CONCLUSIONS

This study highlights considerable morbidity and mortality associated with ASMD type B and type A/B in Germany. It further emphasises the importance of effective therapy for chronic ASMD to reduce disease complications.

The Genetic Basis, Lung Involvement, and Therapeutic Options in Niemann-Pick Disease: A Comprehensive Review

Niemann-Pick Disease (NPD) is a rare autosomal recessive disease belonging to lysosomal storage disorders. Three types of NPD have been described: NPD type A, B, and C. NPD type A and B are caused by mutations in the gene SMPD1 coding for sphingomyelin phosphodiesterase 1, with a consequent lack of acid sphingomyelinase activity. These diseases have been thus classified as acid sphingomyelinase deficiencies (ASMDs). NPD type C is a neurologic disorder due to mutations in the genes NPC1 or NPC2, causing a defect of cholesterol trafficking and esterification. Although all three types of NPD can manifest with pulmonary involvement, lung disease occurs more frequently in NPD type B, typically with interstitial lung disease, recurrent pulmonary infections, and respiratory failure. In this sense, bronchoscopy with broncho-alveolar lavage or biopsy together with high-resolution computed tomography are fundamental diagnostic tools. Although several efforts have been made to find an effective therapy for NPD, to date, only limited therapeutic options are available. Enzyme replacement therapy with Olipudase α is the first and only approved disease-modifying therapy for patients with ASMD. A lung transplant and hematopoietic stem cell transplantation are also described for ASMD in the literature. The only approved disease-modifying therapy in NPD type C is miglustat, a substrate-reduction treatment. The aim of this review was to delineate a state of the art on the genetic basis and lung involvement in NPD, focusing on clinical manifestations, radiologic and histopathologic characteristics of the disease, and available therapeutic options, with a gaze on future therapeutic strategies.

Real-life impacts of olipudase alfa: The experience of patients and families taking an enzyme replacement therapy for acid sphingomyelinase deficiency

BACKGROUND

Acid Sphingomyelinase Deficiency (ASMD) is an ultra-rare autosomal recessive lysosomal storage disorder characterized by intracellular lipid accumulation resulting from reduced function of acid sphingomyelinase. Olipudase alfa, an enzyme replacement therapy, was recently approved in several countries for the treatment of the non-neurologic manifestations of ASMD. Studies demonstrate improvement in organomegaly, pulmonary function and lipid profiles with olipudase alfa, yet little is known about its impact on quality of life (QoL) for patients and caregivers. The purpose of this study is to better understand the real-life impact of ASMD on patients and caregivers and assess how olipudase alfa impacts QoL for pediatric patients and their caregivers.

METHODS

Caregivers of pediatric patients (≤ 18 years of age) with a confirmed diagnosis of ASMD that received olipudase alfa for at least 12 months were recruited in early 2022 through national patient organizations to participate in a global online questionnaire followed by semi-structured interviews. Ten caregivers of patients with ASMD who utilized olipudase alfa as an experimental therapy for pediatric patients participated in the study. Quantitative analysis of the results was undertaken, and qualitative data was analyzed using an inductive thematic approach.

RESULTS

Ten eligible participants completed questionnaires, and 8 of the 10 went on to participate in structured interviews. Symptom burden of ASMD and impact on symptomatology and quality of life after olipudase alfa use are reported here. Five themes emerged from analysis: (1) ASMD is a systemic disease with a wide array of manifestations that significantly impact QoL; (2) Olipudase alfa was associated with improvements in all non-neurologic manifestations of ASMD; (3) Participants perceived the risk associated with olipudase alfa to be low and the benefits to greatly outweigh any risk or burden; (4) Participants reported an unmet need to treat the neurologic manifestations of the disease despite the benefits of olipudase alfa in the management of non-neurological symptoms; (5) Participants felt all patients with ASMD need access to olipudase alfa based on the life-changing experience they perceived.

CONCLUSIONS

These findings highlight the sustained positive impact olipudase alfa had in many domains that are deemed important to patients and families living with ASMD and outline the extensive unmet need for patients and families living with ASMD.

Continued improvement in disease manifestations of acid sphingomyelinase deficiency for adults with up to 2 years of olipudase alfa treatment: open-label extension of the ASCEND trial

BACKGROUND

Olipudase alfa is a recombinant human acid sphingomyelinase enzyme replacement therapy for non-central-nervous-system manifestations of acid sphingomyelinase deficiency (ASMD). The ASCEND randomized placebo-controlled trial in adults with ASMD demonstrated reductions in sphingomyelin storage, organomegaly, interstitial lung disease and impaired diffusion capacity of the lung (DLCO), during the first year of olipudase alfa treatment. In an ongoing open-label extension of the ASCEND trial, individuals in the placebo group crossed over to olipudase alfa, and those in the olipudase alfa group continued treatment.

RESULTS

Thirty-five of 36 participants continued in the extension trial, and 33 completed year 2. Change-from-baseline results are presented as least-square mean percent change ± SEM. Improvements in the cross-over group after 1 year of treatment paralleled those of the olipudase alfa group from the primary analysis, while clinical improvement continued for those receiving olipudase alfa for 2 years. In the cross-over group, percent-predicted DLCO increased by 28.0 ± 6.2%, spleen volume decreased by 36.0 ± 3.0% and liver volume decreased by 30.7 ± 2.5%. For those with 2 years of olipudase alfa treatment, the percent predicted DLCO increased by 28.5 ± 6.2%, spleen volume decreased by 47.0 ± 2.7%, and liver volume decreased by 33.4 ± 2.2%. Lipid profiles and elevated liver transaminase levels improved or normalized by 1 year and remained stable through 2 years of treatment. Overall, 99% of treatment-emergent adverse events were mild or moderate, with one treatment-related serious adverse event (extrasystoles; previously documented cardiomyopathy). No individual discontinued due to an adverse event.

CONCLUSION

Treatment with olipudase alfa is well tolerated and reduces manifestations of chronic ASMD with sustained efficacy. Trial registration NCT02004691 registered 9 December 2013, https://clinicaltrials.gov/ct2/show/NCT02004691.

Effect of acid sphingomyelinase deficiency in type A Niemann-Pick disease on the transport of therapeutic nanocarriers across the blood-brain barrier

ASM deficiency in Niemann-Pick disease type A results in aberrant cellular accumulation of sphingomyelin, neuroinflammation, neurodegeneration, and early death. There is no available treatment because enzyme replacement therapy cannot surmount the blood-brain barrier (BBB). Nanocarriers (NCs) targeted across the BBB via transcytosis might help; yet, whether ASM deficiency alters transcytosis remains poorly characterized. We investigated this using model NCs targeted to intracellular adhesion molecule-1 (ICAM-1), transferrin receptor (TfR), or plasmalemma vesicle-associated protein-1 (PV1) in ASM-normal vs. ASM-deficient BBB models. Disease differentially changed the expression of all three targets, with ICAM-1 becoming the highest. Apical binding and uptake of anti-TfR NCs and anti-PV1 NCs were unaffected by disease, while anti-ICAM-1 NCs had increased apical binding and decreased uptake rate, resulting in unchanged intracellular NCs. Additionally, anti-ICAM-1 NCs underwent basolateral reuptake after transcytosis, whose rate was decreased by disease, as for apical uptake. Consequently, disease increased the effective transcytosis rate for anti-ICAM-1 NCs. Increased transcytosis was also observed for anti-PV1 NCs, while anti-TfR NCs remained unaffected. A fraction of each formulation trafficked to endothelial lysosomes. This was decreased in disease for anti-ICAM-1 NCs and anti-PV1 NCs, agreeing with opposite transcytosis changes, while it increased for anti-TfR NCs. Overall, these variations in receptor expression and NC transport resulted in anti-ICAM-1 NCs displaying the highest absolute transcytosis in the disease condition. Furthermore, these results revealed that ASM deficiency can differently alter these processes depending on the particular target, for which this type of study is key to guide the design of therapeutic NCs.

[Ocular manifestation of an adult Niemann-Pick disease type B]

Niemann-Pick disease is a rare, autosomal recessive inherited lysosomal storage disorder. The pathophysiological background for this condition is the deficiency or reduced function of the enzyme sphingomyelinase, as well as a deficiency in the intracellular cholesterol transporter protein. Due to the breakdown defect, sphingomyelin and cholesterol accumulate in the lysosomes of cells. The disease is divided into 5 subtypes (A, A/B, B, C, D). The authors present the case of a 24-year-old young man diagnosed with Niemann-Pick disease type B as a child, focusing on the ophthalmic manifestation of the disease. During the examination of the patient, fundus photographs and fundus autofluorescence imaging were taken, and optical coherence tomography (OCT), optical coherence tomography angiography (OCTA), and visual field (perimetry) examinations were performed. The characteristic macular halo and the cherry-red spot in the fovea were clearly visible during ophthalmoscopy and on the fundus photographs. The OCT images showed focal thickening with high reflectivity in the ganglion cell layer corresponding to the macular halo, and the area of the foveola was spared. With visual field examination, an intact field of vision was found on both eyes. Similar to the presented patient, symptoms in patients with the B subtype are milder, and besides the visceral symptoms, there are no neurological symptoms, and the specific ophthalmic abnormalities do not cause visual impairment. Currently, Niemann-Pick disease is considered a rare disease, and the diagnosis of the patients is often delayed or even missed due to non-specific or mild symptoms. Through consultation between medical specialties, ophthalmological examination can also contribute to the correct diagnosis in cases with mild general symptoms. Timely diagnosis can potentially lead to mitigation of symptoms thanks to the ever-expanding therapeutic options, stabilization of the disease progression, and increase of the patients' life expectancy. Orv Hetil. 2023; 164(46): 1838-1844.

[Research advances in pharmacotherapy for rare diseases in children]

There are more than 7 000 rare diseases and approximately 475 million individuals with rare diseases globally, with children accounting for two-thirds of this population. Due to a relatively small patient population and limited financial resources allocated for drug research and development in pharmaceutical enterprises, there are still no drugs approved for the treatment of several thousands of these rare diseases. At present, there are no drugs for 95% of the patients with rare diseases, and consequently, the therapeutic drugs for rare diseases have been designated as orphan drugs. In order to guide pharmaceutical enterprises to strengthen the research and development of orphan drugs, various nations have enacted the acts for rare disease drugs, promoted and simplified the patent application process for orphan drugs, and provided scientific recommendations and guidance for the research and development of orphan drugs. Since there is a relatively high incidence rate of rare diseases in children, this article reviews the latest research on pharmacotherapy for children with rare diseases.

Expert opinion on patient journey, diagnosis and clinical monitoring in acid sphingomyelinase deficiency in Turkey: a pediatric metabolic disease specialist's perspective

This review by a panel of pediatric metabolic disease specialists aimed to provide a practical and implementable guidance document to assist clinicians in best clinical practice in terms of recognition, diagnosis and management of patients with acid sphingomyelinase deficiency (ASMD). The participating experts consider the clinical suspicion of ASMD by the physician to be of utmost importance in the prevention of diagnostic delay and strongly suggest the use of a diagnostic algorithm including/starting with dried blood spots assay in the timely diagnosis of ASMD in patients presenting with hepatosplenomegaly and a need for increased awareness among physicians in this regard to consider ASMD in the differential diagnosis. In anticipation of the introduction of enzyme replacement therapy, raising awareness of the disease among physicians to prevent diagnostic delay and further investigation addressing natural history of ASMD across the disease spectrum, potential presenting characteristics with a high index of suspicion, as well as biomarkers and genotype-phenotype correlations suggestive of poor prognosis seem important in terms of implementation of best practice patterns.

Novel Therapeutic Approaches in Inherited Neuropathies: A Systematic Review

The management of inherited neuropathies relies mostly on the treatment of symptoms. In recent years, a better understanding of the pathogenic mechanisms that underlie neuropathies has allowed for the development of disease-modifying therapies. Here, we systematically review the therapies that have emerged in this field over the last five years. An updated list of diseases with peripheral neuropathy as a clinical feature was created based on panels of genes used clinically to diagnose inherited neuropathy. This list was extended by an analysis of published data by the authors and verified by two experts. A comprehensive search for studies of human patients suffering from one of the diseases in our list yielded 28 studies that assessed neuropathy as a primary or secondary outcome. Although the use of various scales and scoring systems made comparisons difficult, this analysis identified diseases associated with neuropathy for which approved therapies exist. An important finding is that the symptoms and/or biomarkers of neuropathies were assessed only in a minority of cases. Therefore, further investigation of treatment efficacy on neuropathies in future trials must employ objective, consistent methods such as wearable technologies, motor unit indexes, MRI or sonography imaging, or the use of blood biomarkers associated with consistent nerve conduction studies.

Olipudase Alfa in Non-CNS Manifestations of Acid Sphingomyelinase Deficiency: A Profile of Its Use

Olipudase alfa (Xenpozyme™) is an intravenously administered acid sphingomyelinase enzyme replacement therapy indicated to treat non-CNS manifestations of acid sphingomyelinase deficiency (ASMD) in adult and paediatric patients. It is the first and currently the only disease-modifying treatment for ASMD. Olipudase alfa treatment improves hepatosplenomegaly, lung function and platelet counts, along with multiple other pathological features of ASMD in adult and paediatric patients with ASMD. These benefits are sustained through at least 24 months of treatment. Olipudase alfa is generally well tolerated; infusion-associated reactions (mostly mild) were the most common treatment-related adverse events. Other warnings and precautions associated with its use include risks of hypersensitivity reactions (including anaphylaxis) and elevated transaminase levels seen in clinical trials, and foetal malformation based on animal studies. All these risks are generally manageable. A gradual dose escalation of olipudase alfa, followed by a maintenance phase, is required to reduce the risks of toxic sphingomyelin catabolites build up, infusion-associated reactions and transient transaminase elevations.

Healthcare Service Use Patterns Among Patients with Acid Sphingomyelinase Deficiency Type B: A Retrospective US Claims Analysis

INTRODUCTION

Acid sphingomyelinase deficiency (ASMD) is a rare lysosomal storage disease. Patients with ASMD type B experience multiple morbidities, potentially leading to early mortality. Before the 2022 approval of olipudase alfa for non-neuronopathic ASMD manifestations, only symptom management was offered. Data on healthcare services used by patients with ASMD type B are limited. This analysis used medical claims data to evaluate real-world healthcare service use by patients with ASMD type B in the United States of America (USA).

METHODS

The IQVIA Open Claims patient-level database (2010-2019) was cross-examined. Two patient cohorts were identified: the primary analysis cohort, which included patients with at least two claims associated with ASMD type B (ICD-10 code E75.241) and more total claims with ASMD type B than any other ASMD types, and the sensitivity analysis cohort, which included patients with a high probability of having ASMD type B identified using a validated machine-learning algorithm. Claims for ASMD-associated healthcare services were recorded, including outpatient visits, emergency department (ED) visits, and inpatient hospitalizations.

RESULTS

The primary analysis cohort included 47 patients; a further 59 patients made up the sensitivity analysis cohort. Patient characteristics and healthcare service use were similar in both cohorts and were consistent with established characteristics of ASMD type B. Overall, 70% of the primary analysis cohort from this study were aged < 18 years, and the liver, spleen, and lungs were the most frequently affected organs. Cognitive, developmental, and/or emotional problems and respiratory/lung disorders caused most outpatient visits; respiratory/lung disorders accounted for most ED visits and hospitalizations.

CONCLUSION

This retrospective analysis of medical claims data identified patients with ASMD type B who had characteristics typical of this condition. A machine-learning algorithm detected further cases with a high probability of having ASMD type B. High use of ASMD-related healthcare services and medications was observed in both cohorts.

Olipudase alfa enzyme replacement therapy for acid sphingomyelinase deficiency (ASMD): sustained improvements in clinical outcomes after 6.5 years of treatment in adults

BACKGROUND

Enzyme replacement therapy with olipudase alfa, a recombinant human acid sphingomyelinase (rhASM), is indicated for non-central nervous system manifestations of acid sphingomyelinase deficiency (ASMD) in children and adults. An ongoing, open-label, long-term study (NCT02004704) assessed the safety and efficacy of olipudase alfa in 5 adults with ASMD.

RESULTS

After 6.5 years of treatment, there were no discontinuations, no olipudase-alfa-related serious adverse events, and no new safety signals compared to earlier assessments. Most treatment-emergent adverse events were mild in intensity (1742/1766, 98.6%). Among treatment-related adverse events (n = 657), more than half were considered infusion-associated reactions (n = 403, 61.3%) such as headache, nausea, abdominal pain, arthralgia, pyrexia, and fatigue. No patient developed neutralizing anti-drug antibodies to cellular uptake, and there were no clinically significant adverse changes in vital signs, hematology, or cardiac safety parameters. Improvements (decreases) in spleen and liver volumes progressed through 6.5 years (mean changes from baseline of -59.5% and  -43.7%, respectively). There was a mean increase in diffusing capacity of the lung for carbon monoxide from baseline of 55.3%, accompanied by improvements in interstitial lung disease parameters. Lipid profiles at baseline indicated dyslipidemia. All patients had sustained decreases in pro-atherogenic lipid levels and increases in anti-atherogenic lipid levels following olipudase alfa treatment.

CONCLUSIONS

Olipudase alfa is the first disease-specific treatment for ASMD. This study demonstrates that long-term treatment with olipudase alfa is well-tolerated and is associated with sustained improvements in relevant disease clinical measures. NCT02004704 registered 26 November 2013, https://clinicaltrials.gov/ct2/show/NCT02004704?term=NCT02004704&draw=2&rank=1 .

Consensus clinical management guidelines for acid sphingomyelinase deficiency (Niemann-Pick disease types A, B and A/B)

BACKGROUND

Acid Sphingomyelinase Deficiency (ASMD) is a rare autosomal recessive disorder caused by mutations in the SMPD1 gene. This rarity contributes to misdiagnosis, delayed diagnosis and barriers to good care. There are no published national or international consensus guidelines for the diagnosis and management of patients with ASMD. For these reasons, we have developed clinical guidelines that defines standard of care for ASMD patients.

METHODS

The information contained in these guidelines was obtained through a systematic literature review and the experiences of the authors in their care of patients with ASMD. We adopted the Appraisal of Guidelines for Research and Evaluation (AGREE II) system as method of choice for the guideline development process.

RESULTS

The clinical spectrum of ASMD, although a continuum, varies substantially with subtypes ranging from a fatal infantile neurovisceral disorder to an adult-onset chronic visceral disease. We produced 39 conclusive statements and scored them according to level of evidence, strengths of recommendations and expert opinions. In addition, these guidelines have identified knowledge gaps that must be filled by future research.

CONCLUSION

These guidelines can inform care providers, care funders, patients and their carers about best clinical practice and leads to a step change in the quality of care for patients with ASMD with or without enzyme replacement therapy (ERT).

Acid sphingomyelinase deficiency (ASMD): addressing knowledge gaps in unmet needs and patient journey in Italy-a Delphi consensus

Acid sphingomyelinase deficiency (ASMD) is an ultra-rare disease, and several gaps of knowledge on various issues remain, particularly at a regional/national level. Expert opinions collected through well-defined consensus methodologies are increasingly used to make available reliable information in the context of rare/ultra-rare diseases. With the aim to provide indications on infantile neurovisceral ASMD (also formerly known as Niemann-Pick disease type A), chronic neurovisceral ASMD (formerly known as Niemann-Pick disease type A/B) and chronic visceral ASMD (formerly known as Niemann-Pick disease type B) in Italy, we conducted a Delphi consensus of experts focused on five main areas: (i) patients and disease characteristics; (ii) unmet needs and quality of life; (iii) diagnostic issues; (iv) treatment-related aspects; and (v) patient journey. Pre-specified, objective criteria were used to outline the multidisciplinary panel, based on 19 Italian experts in ASMD in paediatric and adult patients from different Italian Regions, including both clinicians (n = 16) and ASMD patients' advocacy or payors with expertise in rare diseases (n = 3). During two Delphi rounds, a high ratio of agreement was found on several topics related to ASMD characteristics, diagnosis, management and disease burden. Our findings may provide valuable indications for management of ASMD at a public health level in Italy.

Zebra-Sphinx: Modeling Sphingolipidoses in Zebrafish

Sphingolipidoses are inborn errors of metabolism due to the pathogenic mutation of genes that encode for lysosomal enzymes, transporters, or enzyme cofactors that participate in the sphingolipid catabolism. They represent a subgroup of lysosomal storage diseases characterized by the gradual lysosomal accumulation of the substrate(s) of the defective proteins. The clinical presentation of patients affected by sphingolipid storage disorders ranges from a mild progression for some juvenile- or adult-onset forms to severe/fatal infantile forms. Despite significant therapeutic achievements, novel strategies are required at basic, clinical, and translational levels to improve patient outcomes. On these bases, the development of in vivo models is crucial for a better understanding of the pathogenesis of sphingolipidoses and for the development of efficacious therapeutic strategies. The teleost zebrafish (Danio rerio) has emerged as a useful platform to model several human genetic diseases owing to the high grade of genome conservation between human and zebrafish, combined with precise genome editing and the ease of manipulation. In addition, lipidomic studies have allowed the identification in zebrafish of all of the main classes of lipids present in mammals, supporting the possibility to model diseases of the lipidic metabolism in this animal species with the advantage of using mammalian lipid databases for data processing. This review highlights the use of zebrafish as an innovative model system to gain novel insights into the pathogenesis of sphingolipidoses, with possible implications for the identification of more efficacious therapeutic approaches.

The Niemann-Pick type diseases – A synopsis of inborn errors in sphingolipid and cholesterol metabolism

Disturbances of lipid homeostasis in cells provoke human diseases. The elucidation of the underlying mechanisms and the development of efficient therapies represent formidable challenges for biomedical research. Exemplary cases are two rare, autosomal recessive, and ultimately fatal lysosomal diseases historically named "Niemann-Pick" honoring the physicians, whose pioneering observations led to their discovery. Acid sphingomyelinase deficiency (ASMD) and Niemann-Pick type C disease (NPCD) are caused by specific variants of the sphingomyelin phosphodiesterase 1 (SMPD1) and NPC intracellular cholesterol transporter 1 (NPC1) or NPC intracellular cholesterol transporter 2 (NPC2) genes that perturb homeostasis of two key membrane components, sphingomyelin and cholesterol, respectively. Patients with severe forms of these diseases present visceral and neurologic symptoms and succumb to premature death. This synopsis traces the tortuous discovery of the Niemann-Pick diseases, highlights important advances with respect to genetic culprits and cellular mechanisms, and exposes efforts to improve diagnosis and to explore new therapeutic approaches.

Impact of Potential Symptoms and Risks Associated with Acid Sphingomyelinase Deficiency on Patients and Caregivers: A Best-Worst Scaling Study

Purpose

Acid sphingomyelinase deficiency (ASMD) is a rare, progressive, and potentially fatal disease affecting major organs; its symptoms present heterogeneously. Data on the most bothersome symptoms for patients with ASMD types B or A/B and their caregivers or parents are limited. We conducted a survey to quantify the relative impact of potential ASMD symptoms and risks for patients and parents/caregivers.

Patients and Methods

Twenty respondents, recruited via National Niemann-Pick Disease Foundation (United States) and Niemann-Pick United Kingdom, took a preference survey: 11 patients who had a self-reported diagnosis of ASMD types B or A/B and 9 parents who had a child with ASMD types B or A/B. Using object-case best-worst scaling, we explored the most and least bothersome among a set of 15 ASMD symptoms/risks selected based on clinical input and qualitative research with patients and caregivers. In 15 experimentally designed questions containing five items each, respondents ranked the symptoms/risks, irrespective of their experiences with them. Data were analyzed using a conditional multinomial logit model.

Results

Patients reported constant abdominal pain, severe pain in bones and joints, and severe fatigue to be the most bothersome potential symptoms or risks, followed by a chance of bleeding in the spleen. The next most bothersome potential symptom was constant shortness of breath. Easy bruising and noticeable abdominal enlargement were among the least bothersome symptoms. The most bothersome symptom for parents was bleeding in the spleen.

Conclusion

Patients and parents had similar perceptions of the most bothersome potential symptoms/risks. Despite the small sample size typical of rare disease studies, understanding patient preferences is important for such diseases and can inform shared decision-making.

Enzyme replacement therapy for children with acid sphingomyelinase deficiency in the real world: A single center experience in Taiwan

Background

Acid sphingomyelinase deficiency (ASMD) is a lysosomal storage disease with multi-systemic involvement, with no disease-modifying treatment available. Olipudase alfa is an investigational enzyme product developed to replace the deficient acid sphingomyelinase in ASMD patients. Several clinical trials have reported promising safety and efficacy results in adult and pediatric patients. However, no data have been reported outside of the clinical trial setting yet. This study aimed to evaluate major outcomes in pediatric chronic ASMD patients receiving olipudase alfa in the real-world setting.

Materials and methods

Two children with type A/B (chronic neuropathic) ASMD have received olipudase alfa treatment since May 2021. Clinical parameters, including height, weight, complete blood count, liver function tests, lipid profiles, biomarkers, abdominal ultrasonography with shear wave elastography, chest computed tomography, nerve conduction studies, neurodevelopmental evaluations, and six-minute walk tests, were checked at baseline and every three to six months in the first year of enzyme replacement therapy (ERT) to assess its efficacy and safety.

Results

The two patients in our study started olipudase alfa treatment at the age of 5 years and 8 months and 2 years and 6 months. During the first year of treatment, both patients saw a reduction in their hepatic and splenic volumes as well as liver stiffness. Height z-score, weight z-score, lipid profiles, biomarker levels, interstitial lung disease scores, and bone mineral densities also improved over time. The six-minute walk test showed a gradual increase in walking distance in both patients. There were no obvious improvements or deterioration in neurocognitive function and peripheral nerve conduction velocities after treatment. No severe infusion-associated reactions were noted during the first year of treatment. One patient had two episodes of transient but significantly elevated liver enzymes during the dose-escalation phase. The patient was asymptomatic, and the impaired liver function resolved spontaneously within two weeks.

Conclusion

Our results provide real-world experience that olipudase alfa is safe and effective in improving major systemic clinical outcomes for pediatric chronic ASMD patients. Monitoring of liver stiffness by shear wave elastography is a noninvasive procedure that can monitor treatment efficacy during ERT.

Current Status of Peptide Medications and the Position of Active Therapeutic Peptides with Scorpion Venom Origin

: Peptides are highly potent, selective, and relatively safe therapeutics. Over the past two decades, natural peptides have been obtained, studied, and eventually approved by the Food and Drug Administration (FDA) due to advancements in identification, production, modification, and analytical technologies. Some peptide therapeutics has been derived from the venom gland of venomous animals, including snake, leech, lizard, snail, and scorpion. Scorpion was identified as a reservoir of important peptides with pharmaceutical properties. The scorpion uses these peptides for capturing prey and defense. However, their pharmacological properties in treating different diseases, including cardiac problems, autoimmune and infectious diseases, and diverse cancers, have been confirmed. Ion channel modifiers are the greatest components of the scorpion venom glands. Due to advances in proteomic and transcriptomic approaches, the identification of new scorpion venom peptides is steadily increasing. In this review, we tried to represent the current status of peptide medicines and describe the last peptide medications approved by FDA in 2022. Moreover, we will further explain potent peptides originating from scorpion venom, which have gone through important steps to be approved.

Gene Therapy of Sphingolipid Metabolic Disorders

Sphingolipidoses are defined as a group of rare hereditary diseases resulting from mutations in the genes encoding lysosomal enzymes. This group of lysosomal storage diseases includes more than 10 genetic disorders, including GM1-gangliosidosis, Tay-Sachs disease, Sandhoff disease, the AB variant of GM2-gangliosidosis, Fabry disease, Gaucher disease, metachromatic leukodystrophy, Krabbe disease, Niemann-Pick disease, Farber disease, etc. Enzyme deficiency results in accumulation of sphingolipids in various cell types, and the nervous system is also usually affected. There are currently no known effective methods for the treatment of sphingolipidoses; however, gene therapy seems to be a promising therapeutic variant for this group of diseases. In this review, we discuss gene therapy approaches for sphingolipidoses that are currently being investigated in clinical trials, among which adeno-associated viral vector-based approaches and transplantation of hematopoietic stem cells genetically modified with lentiviral vectors seem to be the most effective.

Similarities and differences between Gaucher disease and acid sphingomyelinase deficiency: An algorithm to support the diagnosis

Lysosomal storage disorders are a group of inborn errors of metabolism due to defects in proteins crucial for lysosomal function. Gaucher disease is the most common autosomal recessive lysosomal storage disorder due to mutations in the GBA1 gene, resulting in the lysosomal deficiency of glucocerebrosidase activity. Gaucher disease is characterized by the toxic accumulation of glucosylceramide in the reticuloendothelial system. Acid sphingomyelinase deficiency (ASMD), previously known as Niemann Pick A/B disease, is also an autosomal recessive lysosomal storage disorder due to mutations in the SMPD1 gene, which result in acid sphingomyelinase deficiency and the accumulation of sphingomyelin in mononuclear phagocytic system and hepatocytes. The phenotypic expression of Gaucher disease type 1 (GD1), the most common type, and chronic visceral ASMD may overlap for several signs or symptoms. Splenomegaly is detectable in approximately 90% of the patients in both conditions; however, since GD1 is more frequent than ASMD, clinicians are more prone to suspect it, often neglecting the diagnosis of ASMD. Based on previous experience, a group of experts in the clinical and laboratory diagnosis, management, and treatment of lysosomal storage disorders developed an algorithm for both GD1 and ASMD to support physicians, including primary care providers, internists, and specialists (e.g., hepatologists, hematologists, and pulmonologists) to suspect and differentiate GD1 and ASMD and to provide the appropriate referral.

Long-term safety and clinical outcomes of olipudase alfa enzyme replacement therapy in pediatric patients with acid sphingomyelinase deficiency: two-year results

BACKGROUND

Olipudase alfa is a recombinant human acid sphingomyelinase (ASM) enzyme replacement therapy (ERT) for non-central-nervous-system manifestations of acid sphingomyelinase deficiency (ASMD). We report 2-year cumulative safety and efficacy data after olipudase alfa treatment in 20 children (four adolescents [12-17 year], nine children [6-11 year], and seven infants/early child [1-5 year]) with baseline splenomegaly and growth deficits who completed the 1-year ASCEND-Peds clinical trial (NCT02292654) and who continue to receive olipudase alfa in a long-term study (NCT02004704). Efficacy endpoints include spleen and liver volumes, diffusing capacity of the lung for carbon monoxide (DL_CO), high-resolution computed tomography (HRCT) lung imaging, lipid profiles, liver function tests, and height Z-scores.

RESULTS

All 20 former ASCEND-Peds patients completed at least 2 years of olipudase alfa treatment. No patient discontinued and no new safety issue arose during the second year of treatment; 99% of adverse events were mild or moderate. During year 2, one patient had two treatment-related serious events of hypersensitivity that resolved. Mean reductions from baseline in spleen and liver volumes were 61% and 49%, respectively (p < 0.0001) and mean percent-predicted-DL_CO increased by 46.6% (p < 0.0001) in nine patients who performed the test at baseline. Lipid profiles and elevated liver transaminase levels that improved or normalized by 1 year remained stable. Mean height Z-scores improved in all age groups (mean change from baseline 1.17, P < 0.0001).

CONCLUSION

Olipudase alfa was generally well-tolerated during 2 years of treatment. Improvements in clinically relevant disease endpoints observed during the first year of treatment were maintained or augmented in the second year. Trial registration NCT02004704 registered 26 Nov 2013, https://clinicaltrials.gov/ct2/show/record/NCT02004704 .

Cyclodextrins applied to the treatment of lysosomal storage disorders

Cyclodextrin (CD), a cyclic oligosaccharide, is a pharmaceutical additive that improves the solubility of hydrophobic compounds. Recent research has focused on the potential active pharmaceutical abilities of CD. Lysosomal storage diseases are inherited metabolic diseases characterized by lysosomal dysfunction and abnormal lipid storage. Niemann-Pick disease type C (NPC) is caused by mutations in cholesterol transporter genes (NPC1, NPC2) and is characterized by cholesterol accumulation in lysosomes. A biocompatible cholesterol solubilizer 2-hydroxypropyl-β-cyclodextrin (HP-β-CD) was recently used in NPC patients for compassionate use and in clinical trials. HP-β-CD is an attractive drug candidate for NPC; however, its adverse effects, such as ototoxicity, should be solved. In this review, we discuss the current use of HP-β-CD in basic and clinical research and discuss alternative CD derivatives that may outperform HP-β-CD, which should be considered for clinical use. The potential of CD therapy for the treatment of other lysosomal storage diseases is also discussed.

Three-years misdiagnosis of Niemann Pick disease type B with novel mutations in SMPD1 gene as Budd-Chiari syndrome

Background

The chronic visceral subtype of acid sphingomyelinase deficiency, commonly known as Niemann Pick disease type B (NPDB), is a relatively rare autosomal recessive genetic disorder that is caused by mutations in the SMPD1 gene. NPDB with sea-blue histiocytes (SBH) clinically mimics Budd-Chiari syndrome (BCS), as it lacks specific clinical characteristics. This makes its diagnosis difficult.

Case presentation

Here, we report a case of NPDB with SBH that was misdiagnosed as BCS for three years. A 20-year-old female with abdominal distension, hepatosplenomegaly, and haematological anomalies was initially diagnosed with BCS based on her imaging finding of a thin hepatic vein and rapid blood flow at the confluence of the hepatic vein and inferior vena cava. Her bone marrow cytology found sea-blue histiocytes. Liver biopsy showed foamy cytoplasm in hepatocytes surrounded by numerous Kupffer cells. Sequencing analysis of the SMPD1 gene led to the finding of two missense mutations in the heterozygous state: C.829 T > C (p.Trp277Arg) in exon 2 (novel) and c.1805G > A (p.Arg602His) in exon 6 (already described). These findings established the diagnosis of NPDB.

Conclusion

The patient presented with hepatosplenomegaly, haematological anomalies, and dyslipidaemia. Thus, NPDB should be considered following the exclusion of related diseases. The diagnosis of NPDB was suspected by clinical symptoms and routine laboratory tests and was confirmed by liver biopsy and gene sequencing. The novel mutation c.829 T > C in exon 2 of the SMPD1 gene has never been reported and needs to be further investigated.

Acid sphingomyelinase deficiency: The clinical spectrum of 2 patients who carry the Q294K mutation and diagnostic challenges

Acid sphingomyelinase deficiency (ASMD) is caused by pathogenic variants in the SMPD1 gene. This chronic, progressive, and potentially fatal condition requires prompt specialist care. The diagnosis of ASMD can be delayed or missed if patients that harbor the Q294K mutation undergo enzyme activity assessments that employ synthetic fluorometric substrates. Two case studies are presented, which illustrate the spectrum of disease in patients with a compound heterozygous Q294K pathogenic variant and the impact of false normal ASM activity results.

Niemann-Pick type A disease with new mutation: a case report

BACKGROUND

Niemann-Pick type A (NP-A) is a congenital, hereditary disease caused by a deficiency in acid sphingomyelinase, a lysosomal enzyme. This deficiency results in an accumulation of sphingomyelin in lysosomes, leading to cellular apoptosis and ultimately to hepatosplenomegaly, neurodegenerative disorder and failure to thrive. Cherry-red spots in the macula and foamy cells in the bone marrow are other manifestations of the disease that help with diagnosis. Type A is a rare, untreatable disease with early manifestations and a poor prognosis, with newborns rarely surviving for 2-3 years.

CASE PRESENTATION

A 1-year-old Persian boy was referred to our clinic due to abdominal distention and poor weight gain. He was the first male offspring of consanguineous parents. Other findings were neurodevelopmental delay, hepatosplenomegaly, severe hypotonia, difficulty in breathing, and a slightly coarse face with an open mouth and protruding tongue. The initial diagnosis was clinical mucopolysaccharidosis (MPS) based on the coarse facial features, but further workup ruled out this inherited disorder. Enzyme histochemistry revealed that the level of acid sphingomyelinase was lower than normal. In the genetic study, next-generation sequencing of all coding exons and flanking intronic regions of the patient's DNA demonstrated a homozygous c.682T>G variant in the SMPD1 gene. This variant was classified as a variant of unknown significance. Further evaluation of DNA extract from his parents and examined using Sanger sequencing showed a heterozygous c.682T>G variant in the SMPD1 gene of both parents.

CONCLUSIONS

We describe a 1-year-old boy with neurodevelopmental delay, hepatosplenomegaly, and severe hypotonia. Further investigation demonstrated a new mutation for Niemann-Pick disease.

Olipudase Alfa: First Approval

Olipudase alfa (XENPOZYME^®) is a recombinant human acid sphingomyelinase that has been developed by Sanofi, for the treatment of acid sphingomyelinase deficiency (ASMD). Olipudase alfa catalyses the hydrolysis of sphingomyelin accumulated in hepatocytes and in mononuclear-macrophage cells, such as the lungs, liver, spleen, kidneys and bone marrow. Olipudase alfa was approved in Japan under the SAKIGAKE designation on 28 March 2022 for use in adult and paediatric patients with non-CNS manifestations of ASMD and has received a positive Committee for Medicinal Products for Human Use opinion in the EU. Regulatory review in the USA is underway. This article summarizes the milestones in the development of olipudase alfa leading to this first approval for the treatment of patients with ASMD.

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.

Acid Sphingomyelinase Deficiency: Sharing Experience of Disease Monitoring and Severity in France

Acid sphingomyelinase deficiency (ASMD) is a rare inherited lipid storage disorder caused by a deficiency in lysosomal enzyme acid sphingomyelinase which results in the accumulation of sphingomyelin, predominantly within cells of the reticuloendothelial system located in numerous organs, such as the liver, spleen, lungs, and central nervous system. Although all patients with ASMD share the same basic metabolic defect, a wide spectrum of clinical presentations and outcomes are observed, contributing to treatment challenges. While infantile neurovisceral ASMD (also known as Niemann-Pick disease type A) is rapidly progressive and fatal in early childhood, and the more slowly progressive chronic neurovisceral (type A/B) and chronic visceral (type B) forms have varying clinical phenotypes and life expectancy. The prognosis of visceral ASMD is mainly determined by the association of hepatosplenomegaly with secondary thrombocytopenia and lung disease. Early diagnosis and appropriate management are essential to reduce the risk of complications and mortality. The accessibility of the new enzyme replacement therapy olipudase alfa, a recombinant human ASM, has been expedited for clinical use based on positive clinical data in children and adult patients, such as improved respiratory status and reduced spleen volume. The aim of this article is to share the authors experience on monitoring ASMD patients and stratifying the severity of the disease to aid in care decisions.

The past, present, and future of enzyme-based therapies

Enzyme-based therapeutics (EBTs) have the potential to tap into an almost unmeasurable amount of enzyme biodiversity and treat myriad conditions. Although EBTs were some of the first biologics used clinically, the rate of development of newer EBTs has lagged behind that of other biologics. Here, we review the history of EBTs, and discuss the state of each class of EBT, their potential clinical advantages, and the unique challenges to their development. Additionally, we discuss key remaining technical barriers that, if addressed, could increase the diversity and rate of the development of EBTs.

Advancing Diagnosis and Treatment of Niemann-Pick C disease through Biomarker Discovery

Niemann-Pick C is a rare neurodegenerative, lysosomal storage disease caused by accumulation of unesterified cholesterol. Diagnosis of the disease is often delayed due to its rarity, the heterogeneous presentation and the early non-specific symptoms. The discovery of disease-specific biomarkers - cholestane-3β,5α,6β-triol (C-triol), trihydroxycholanic acid glycinate (TCG) and N-palmitoyl-O-phosphocholineserine (PPCS, initially referred to as lysoSM-509) - has led to development of non-invasive, blood-based diagnostics. Dissemination of these rapid, sensitive, and specific clinical assays has accelerated diagnosis. Moreover, the superior receiver operating characteristic of the TCG bile acid biomarker and its detection in dried blood spots has also facilitated development of a newborn screen for NPC, which is currently being piloted in New York state. The C-triol, TCG and PPCS biomarkers have also proven useful for monitoring treatment response in peripheral tissues, but are uninformative with respect to treatment efficacy in the central nervous system (CNS). A major gap for the field is the lack of a validated, non-invasive biomarker to monitor the course of disease and CNS response to therapy.

Acid Sphingomyelinase Deficiency: A Clinical and Immunological Perspective

Acid sphingomyelinase deficiency (ASMD) is a lysosomal storage disease caused by deficient activity of acid sphingomyelinase (ASM) enzyme, leading to the accumulation of varying degrees of sphingomyelin. Lipid storage leads to foam cell infiltration in tissues, and clinical features including hepatosplenomegaly, pulmonary insufficiency and in some cases central nervous system involvement. ASM enzyme replacement therapy is currently in clinical trial being the first treatment addressing the underlying pathology of the disease. Therefore, presently, it is critical to better comprehend ASMD to improve its diagnose and monitoring. Lung disease, including recurrent pulmonary infections, are common in ASMD patients. Along with lung disease, several immune system alterations have been described both in patients and in ASMD animal models, thus highlighting the role of ASM enzyme in the immune system. In this review, we summarized the pivotal roles of ASM in several immune system cells namely on macrophages, Natural Killer (NK) cells, NKT cells, B cells and T cells. In addition, an overview of diagnose, monitoring and treatment of ASMD is provided highlighting the new enzyme replacement therapy available.

Focal hepatic lesions in acid sphingomyelinase deficiency: Differential diagnosis between foamy macrophages aggregates and malignancy

Acid sphingomyelinase deficiency (ASMD) is a rare metabolic disorder due to biallelic mutation in the SMPD1 gene. The defect leads to the accumulation of sphingomyelin within the cells of the reticulo-endothelial system, particularly in the spleen, liver, lungs, and bone marrow causing hepato-splenomegaly, lung disease and hematological abnormalities. At present, data on abdominal imaging in ASMD are limited. Here we describe the characteristics of focal liver lesions observed in a 30 years old female. During the Magnetic Resonance follow up an increase in number and size of the lesions, showing T1 hypointensity and T2 hyperintensity with contrast enhancement, was observed. Contrast enhanced ultrasound evidenced rapid wash-in and steady isoecogenicity without appreciable wash-out at 80 seconds. The main lesion was biopsied to rule out the presence of a hepatocellular carcinoma, and showed to be a benign foamy macrophages aggregate. In this report, we discuss the possible pathogenesis of focal hepatic lesions in ASMD and their differential diagnosis.

Acid Sphingomyelinase, a Lysosomal and Secretory Phospholipase C, Is Key for Cellular Phospholipid Catabolism

Here, we present the main features of human acid sphingomyelinase (ASM), its biosynthesis, processing and intracellular trafficking, its structure, its broad substrate specificity, and the proposed mode of action at the surface of the phospholipid substrate carrying intraendolysosomal luminal vesicles. In addition, we discuss the complex regulation of its phospholipid cleaving activity by membrane lipids and lipid-binding proteins. The majority of the literature implies that ASM hydrolyses solely sphingomyelin to generate ceramide and ignores its ability to degrade further substrates. Indeed, more than twenty different phospholipids are cleaved by ASM in vitro, including some minor but functionally important phospholipids such as the growth factor ceramide-1-phosphate and the unique lysosomal lysolipid bis(monoacylglycero)phosphate. The inherited ASM deficiency, Niemann-Pick disease type A and B, impairs mainly, but not only, cellular sphingomyelin catabolism, causing a progressive sphingomyelin accumulation, which furthermore triggers a secondary accumulation of lipids (cholesterol, glucosylceramide, GM2) by inhibiting their turnover in late endosomes and lysosomes. However, ASM appears to be involved in a variety of major cellular functions with a regulatory significance for an increasing number of metabolic disorders. The biochemical characteristics of ASM, their potential effect on cellular lipid turnover, as well as a potential impact on physiological processes will be discussed.

Prospective study of the natural history of chronic acid sphingomyelinase deficiency in children and adults: eleven years of observation

Background

Acid sphingomyelinase deficiency (ASMD) (also known as Niemann-Pick disease types A and B) is a rare and debilitating lysosomal storage disorder. This prospective, multi-center, multinational longitudinal study aimed to characterize the clinical features of chronic forms of ASMD and disease burden over time in children and adults.

Results

Fifty-nine patients (31 males/28 females) ranging in age from 7 to 64 years with chronic ASMD types A/B and B and at least two disease symptoms participated from 5 countries. Disease characteristics were assessed at baseline, after 1 year, and at the final visit (ranging from 4.5 to 11 years). Thirty patients (51%) were < 18 years at baseline (median age 12 years), and 29 were adults (median age 32 years). Overall, 32/59 patients completed the final visit, 9 died, 9 discontinued, and 9 were lost to follow up. Common clinical characteristics that tended to worsen gradually with time were splenomegaly, hepatomegaly, interstitial lung disease, lung diffusion capacity (DL_CO), and dyslipidemia. Spleen volumes ranged from 4 to 29 multiples of normal at baseline, and splenomegaly was moderate or severe in 86%, 83%, and 90% of individuals at baseline, year 1, and final visits, respectively. The proportion of all individuals with interstitial lung disease was 66% (39/59) at baseline and 78% (25/32) at the final visit, while median % predicted DL_CO decreased by > 10% from baseline to the final visit. Nine patients died (15%), eight of causes related to ASMD (most commonly pneumonia); of these eight patients, five (63%) had symptom onset at or before age 2. Overall, six of the nine deaths occurred before age 50 with three occurring before age 20. Individuals with either severe splenomegaly or prior splenectomy were ten times more likely to have died during the follow-up period than those with smaller or intact spleens (odds ratio 10.29, 95% CI 1.7, 62.7). Most children had growth deficits that persisted into adulthood.

Conclusions

This study provides important information about the natural history of chronic ASMD and provides a longitudinal view of the spectrum of disease manifestations and major morbidities in children and adults and supports the selection of clinically meaningful endpoints in therapeutic trials.