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Bremova-Ertl T, Schneider S. Current advancements in therapy for Niemann-Pick disease: progress and pitfalls. Expert Opin Pharmacother 2023; 24:1229-1247. [PMID: 37211769 DOI: 10.1080/14656566.2023.2215386] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Accepted: 05/15/2023] [Indexed: 05/23/2023]
Abstract
INTRODUCTION Niemann-Pick disease type C (NPC) is a rare, autosomal recessive, lysosomal storage disorder. To combat the progressive neurodegeneration in NPC, disease-modifying treatment needs to be introduced early in the course of the disease. The only approved, disease-modifying treatment is a substrate-reduction treatment, miglustat. Given miglustat's limited efficacy, new compounds are under development, including gene therapy; however, many are still far from clinical use. Moreover, the phenotypic heterogeneity and variable course of the disease can impede the development and approval of new agents. AREAS COVERED Here, we offer an expert review of these therapeutic candidates, with a broad scope not only on the main pharmacotherapies, but also on experimental approaches, gene therapies, and symptomatic strategies. The National Institute of Health (NIH) database PubMed has been searched for the combination of the words 'Niemann-Pick type C'+ 'treatment' or 'therapy' or 'trial.' The website clinicaltrials.gov has also been consulted. EXPERT OPINION We conclude a combination of treatment strategies should be sought, with a holistic approach, to improve the quality of life of affected individuals and their families.
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Affiliation(s)
- Tatiana Bremova-Ertl
- Department of Neurology, University Hospital Bern (Inselspital) and University of Bern, Bern, Switzerland
- Center for Rare Diseases, University Hospital Bern (Inselspital) and University of Bern, Bern, Switzerland
| | - Susanne Schneider
- Department of Neurology, Ludwig-Maximilians-University, Munich, Germany
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Abstract
The lysosomal storage disorders are hereditary metabolic disorders characterized by autosomal recessive inheritance, mainly caused by deficiency of an enzyme responsible for the intra-lysosomal breakdown of various substrates and products of cellular metabolism. This chapter examines the underlying defects, clinical manifestations, and provides context for the expected clinical outcome of various available therapy options employing enzyme replacement therapy, hematopoietic stem cell transplantation, substrate reduction, and enzyme enhancement therapies.
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Affiliation(s)
- Gregory M Pastores
- Department of Medicine (Clinical Genetics), National Center for Inherited Metabolic Disorders, Mater Misericordiae University Hospital, Dublin, Ireland; Department of Medicine (Genetics), University College of Dublin School of Medicine, Dublin, Ireland.
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Capitini C, Feo F, Caciotti A, Tonin R, Lulli M, Coviello D, Guerrini R, Calamai M, Morrone A. Fluorescent In Situ Staining and Flow Cytometric Procedures as New Pre-Diagnostic Tests for Sialidosis, GM1 Gangliosidosis and Niemann–Pick Type C. Biomedicines 2022; 10:1962. [PMID: 36009508 PMCID: PMC9405762 DOI: 10.3390/biomedicines10081962] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 08/03/2022] [Accepted: 08/10/2022] [Indexed: 11/16/2022] Open
Abstract
Background: Early diagnosis is essential in the field of lysosomal storage disorders for the proper management of patients and for starting therapies before irreversible damage occurs, particularly in neurodegenerative conditions. Currently, specific biomarkers for the diagnosis of lysosomal storage disorders are lacking in routine laboratory practice, except for enzymatic tests, which are available only in specialized metabolic centers. Recently, we established a method for measuring and verifying changes in GM1 ganglioside levels in peripheral blood lymphocytes in patients with GM1 gangliosidosis. However, fresh blood is not always available, and using frozen/thawed lymphocytes can lead to inaccurate results. Methods: We used frozen/thawed fibroblasts obtained from stored biopsies to explore the feasibility of fluorescent imaging and flow-cytometric methods to track changes in storage materials in fibroblasts from patients with three lysosomal neurodegenerative conditions: GM1 gangliosidosis, Sialidosis, and Niemann–Pick type C. We used specific markers for each pathology. Results and Conclusions: We demonstrated that with our methods, it is possible to clearly distinguish the levels of accumulated metabolites in fibroblasts from affected and unaffected patients for all the three pathologies considered. Our methods proved to be rapid, sensitive, unbiased, and potentially applicable to other LSDs.
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Farhat N, Bailey L, Friedmann K, Bushnell DM, Rodriguez D, Berry-Kravis E, Porter FD. Consistently High Agreement Between Independent Raters of Niemann-Pick Type C1 Clinical Severity Scale in Phase 2/3 Trial. Pediatr Neurol 2022; 127:32-38. [PMID: 34952292 PMCID: PMC8900058 DOI: 10.1016/j.pediatrneurol.2021.11.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Revised: 11/21/2021] [Accepted: 11/23/2021] [Indexed: 02/03/2023]
Abstract
BACKGROUND Niemann-Pick disease, type C1 (NPC1) is a rare neurodegenerative genetic disorder characterized by impaired intracellular transport of cholesterol and other lipids. The Niemann-Pick Disease, type C1 Severity Scale (NPC-SS) was developed to quantify neurological progression of NPC; it is used to monitor the natural history of disease progression and assess response to treatment. The objective of the study was to examine the interrater reliability of the NPC-SS in a phase 2/3 trial. METHODS Study data were from a multicenter, prospective, randomized, double-blind trial of adrabetadex in 56 subjects with NPC1. Clinical data recorded at each study site were distributed to two independent blinded central raters to generate a severity score. A composite four-item score was utilized as the primary clinical study end point, whereas a five-item focused score has been utilized in other NPC1 trials. Interrater reliability was assessed using two-way mixed models for instrument stability, Cohen kappa, weighted kappa, and percent agreement for the four- and five-item scores. RESULTS The frequency distribution and mean (S.D.) of the NPC-SS domain assessments by the raters were almost identical. Evaluation at the patient visit level showed wide variability between visits; however, weighted kappa calculation provided a lower variability between visits. The average kappa coefficients ranged between 0.69 and 0.89, indicating good to very good agreement between raters. CONCLUSIONS These results support the NPC-SS, including derived four- and five-item composite scores, as reliable measures for use in a clinical trial setting.
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Affiliation(s)
- Nicole Farhat
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland.
| | - Laurie Bailey
- Division of Human Genetics, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, USA
| | - Katherine Friedmann
- Department of Pediatrics, Neurological Sciences and Biochemistry, Rush University Medical Center, Chicago, Illinois, USA
| | | | | | - Elizabeth Berry-Kravis
- Department of Pediatrics, Neurological Sciences and Biochemistry, Rush University Medical Center, Chicago, Illinois, USA
| | - Forbes D. Porter
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
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Jiang X, Ory DS. Advancing Diagnosis and Treatment of Niemann-Pick C disease through Biomarker Discovery. Explor Neuroprotective Ther 2021; 1:146-158. [PMID: 35356760 PMCID: PMC8963791 DOI: 10.37349/ent.2021.00012] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2021] [Accepted: 11/05/2021] [Indexed: 05/30/2023]
Abstract
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.
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Affiliation(s)
- Xuntian Jiang
- Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110
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Abstract
Niemann-Pick type C (NPC) disease is a genetically determined neurodegenerative metabolic disease. It belongs to the lysosomal storage diseases and its main cause is impaired cholesterol transport in late endosomes or lysosomes. It is an autosomal recessive inherited disease that results from mutations in the NPC1 or NPC2 genes. The treatment efforts are focused on the slowing its progression. The only registered drug, devoted for NPC patients is Miglustat. Effective treatment is still under development. NPC disease mainly affects the nervous system, and the crossing of the blood-brain barrier by medicines is still a challenge, therefore the combination therapies of several compounds are increasingly being worked on. The aim of this paper is to present the possibilities in treatment of Niemann-Pick type C disease. The discussed research results relate to animal studies.
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Affiliation(s)
- Dominika Sitarska
- Department of Genetics, Institute of Psychiatry and Neurology, Al. Sobieskiego 9, 02-957, Warsaw, Poland.
| | - Anna Tylki-Szymańska
- Department of Pediatric Nutrition and Metabolic Diseases, The Children's Memorial Health Institute, 04-730, Warsaw, Poland
| | - Agnieszka Ługowska
- Department of Genetics, Institute of Psychiatry and Neurology, Al. Sobieskiego 9, 02-957, Warsaw, Poland.
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Evans W, Patterson M, Platt F, Guldberg C, Mathieson T, Pacey J. International consensus on clinical severity scale use in evaluating Niemann-Pick disease Type C in paediatric and adult patients: results from a Delphi Study. Orphanet J Rare Dis 2021; 16:482. [PMID: 34794481 PMCID: PMC8600786 DOI: 10.1186/s13023-021-02115-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Accepted: 11/06/2021] [Indexed: 01/08/2023] Open
Abstract
Background Several scales have been developed in the past two decades to evaluate Niemann–Pick disease Type C (NPC) severity in clinical practice and trials. However, a lack of clarity concerning which scale to use in each setting is preventing the use of standardised assessments across the world, resulting in incomparable data sets and clinical trial outcome measures. This study aimed to establish agreed approaches for the use of NPC severity scales in clinical practice and research. Methods A Delphi method of consensus development was used, comprising three survey rounds. In Round 1, participants were asked nine multiple-choice and open-ended questions to gather opinions on the six severity scales and domains. In Rounds 2 and 3, questions aimed to gain consensus on the opinions revealed in Round 1 using a typical Likert scale. Results Nineteen experts, active in NPC paediatric and adult research and treatment, participated in this study. Of these, 16/19 completed Rounds 1 and 2 and 19/19 completed Round 3. Consensus (defined as ≥ 70% agreement or neutrality, given the study aim to identify the severity scales that the clinical community would accept for international consistency) was achieved for 66.7% of the multiple-choice questions in Round 2 and 83% of the multiple-choice questions in Round 3. Consensus was almost reached (68%) on the use of the 5-domain NPCCSS scale as the first choice in clinical practice. Consensus was reached (74%) for the 17-domain NPCCSS scale as the first choice in clinical trial settings, but the domains measured in the 5-domain scale should be prioritised as the primary endpoints. Experts called for educational and training materials on how to apply the NPCCSS (17- and 5-domains) for clinicians working in NPC. Conclusions In achieving a consensus on the use of the 17-domain NPCCSS scale as the first choice for assessing clinical severity of NPC in clinical trial settings but prioritising the domains in the 5-domain NPCCSS scale for routine clinical practice, this study can help to inform future discussion around the use of the existing NPC clinical severity scales. For routine clinical practice, the study helps provide clarity on which scale is favoured by a significant proportion of a representative body of experts, in this case, the 5-domain NPCCSS scale.
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Affiliation(s)
- William Evans
- NPUK, Suite 2, Vermont House, Concord, Washington, Tyne and Wear, NE37 2SQ, UK. .,Primary Care Stratified Medicine (PRISM), Division of Primary Care, University of Nottingham, Nottingham, UK.
| | - Marc Patterson
- Departments of Neurology, Pediatrics and Medical Genetics, Mayo Clinic Children's Center, Rochester, MN, USA
| | - Frances Platt
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, UK
| | | | - Toni Mathieson
- NPUK, Suite 2, Vermont House, Concord, Washington, Tyne and Wear, NE37 2SQ, UK.,Primary Care Stratified Medicine (PRISM), Division of Primary Care, University of Nottingham, Nottingham, UK
| | - Jessica Pacey
- 67health, Sterling House, Fulbourne Road, Walthamstow, London, E17 4E, UK
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Mengel E, Patterson MC, Da Riol RM, Del Toro M, Deodato F, Gautschi M, Grunewald S, Grønborg S, Harmatz P, Héron B, Maier EM, Roubertie A, Santra S, Tylki‐Szymanska A, Day S, Andreasen AK, Geist MA, Havnsøe Torp Petersen N, Ingemann L, Hansen T, Blaettler T, Kirkegaard T, í Dali C. Efficacy and safety of arimoclomol in Niemann-Pick disease type C: Results from a double-blind, randomised, placebo-controlled, multinational phase 2/3 trial of a novel treatment. J Inherit Metab Dis 2021; 44:1463-1480. [PMID: 34418116 PMCID: PMC9293014 DOI: 10.1002/jimd.12428] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Revised: 08/11/2021] [Accepted: 08/19/2021] [Indexed: 12/13/2022]
Abstract
Niemann-Pick disease type C (NPC) is a rare, genetic, progressive neurodegenerative disorder with high unmet medical need. We investigated the safety and efficacy of arimoclomol, which amplifies the heat shock response to target NPC protein misfolding and improve lysosomal function, in patients with NPC. In a 12-month, prospective, randomised, double-blind, placebo-controlled, phase 2/3 trial (ClinicalTrials.gov identifier: NCT02612129), patients (2-18 years) were randomised 2:1 to arimoclomol:placebo, stratified by miglustat use. Routine clinical care was maintained. Arimoclomol was administered orally three times daily. The primary endpoint was change in 5-domain NPC Clinical Severity Scale (NPCCSS) score from baseline to 12 months. Fifty patients enrolled; 42 completed. At month 12, the mean progression from baseline in the 5-domain NPCCSS was 0.76 with arimoclomol vs 2.15 with placebo. A statistically significant treatment difference in favour of arimoclomol of -1.40 (95% confidence interval: -2.76, -0.03; P = .046) was observed, corresponding to a 65% reduction in annual disease progression. In the prespecified subgroup of patients receiving miglustat as routine care, arimoclomol resulted in stabilisation of disease severity over 12 months with a treatment difference of -2.06 in favour of arimoclomol (P = .006). Adverse events occurred in 30/34 patients (88.2%) receiving arimoclomol and 12/16 (75.0%) receiving placebo. Fewer patients had serious adverse events with arimoclomol (5/34, 14.7%) vs placebo (5/16, 31.3%). Treatment-related serious adverse events (n = 2) included urticaria and angioedema. Arimoclomol provided a significant and clinically meaningful treatment effect in NPC and was well tolerated.
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Affiliation(s)
- Eugen Mengel
- SphinCS GmbHInstitute of Clinical Science for LSDHochheimGermany
| | - Marc C. Patterson
- Departments of Neurology, Pediatrics and Medical GeneticsMayo ClinicRochesterMinnesotaUSA
| | - Rosalia M. Da Riol
- Regional Coordination Center for Rare DiseasesAcademic Hospital ‘Santa Maria della Misericordia’UdineItaly
| | - Mireia Del Toro
- Pediatric Neurology DepartmentVall d'Hebron University HospitalBarcelonaSpain
| | - Federica Deodato
- Division of MetabolismOspedale Pediatrico Bambino Gesù, IRCCSRomeItaly
| | - Matthias Gautschi
- Department of Paediatrics, Division of Endocrinology, Diabetology and Metabolism, and Institute of Clinical Chemistry, InselspitalUniversity Hospital Bern, University of BernBernSwitzerland
| | - Stephanie Grunewald
- Department of Metabolic MedicineGreat Ormond Street Hospital, Institute of Child Health, UCL, NIHR Biomedical Research CenterLondonUK
| | - Sabine Grønborg
- Centre for Inherited Metabolic DiseasesCopenhagen University Hospital (Rigshospitalet)CopenhagenDenmark
| | - Paul Harmatz
- Gastroenterology and HepatologyUCSF Benioff Children's Hospital OaklandOaklandCaliforniaUSA
| | - Bénédicte Héron
- Department of Pediatric Neurology, Reference Centre for Lysosomal DiseasesUniversity Hospital Armand TrousseauParisFrance
| | - Esther M. Maier
- Department of Inborn Errors of MetabolismUniversity of Munich Children's HospitalMunichGermany
| | - Agathe Roubertie
- Department of NeuropediatricsCentre Hospitalier Universitaire de MontpellierMontpellierFrance
| | - Saikat Santra
- Department of Inherited Metabolic DisordersBirmingham Children's HospitalBirminghamUK
| | - Anna Tylki‐Szymanska
- Department of Paediatrics, Nutrition and Metabolic DiseasesThe Children's Memorial InstituteWarsawPoland
| | - Simon Day
- BiostatisticsClinical Trials Consulting & Training LimitedBuckinghamUK
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Mengel E, Bembi B, Del Toro M, Deodato F, Gautschi M, Grunewald S, Grønborg S, Héron B, Maier EM, Roubertie A, Santra S, Tylki-Szymanska A, Day S, Symonds T, Hudgens S, Patterson MC, Guldberg C, Ingemann L, Petersen NHT, Kirkegaard T, Dali CÍ. Correction to: Clinical disease progression and biomarkers in Niemann-Pick disease type C: a prospective cohort study. Orphanet J Rare Dis 2021; 16:246. [PMID: 34074315 PMCID: PMC8168003 DOI: 10.1186/s13023-021-01855-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Affiliation(s)
- Eugen Mengel
- SphinCS GmbH, Institute of Clinical Science for LSD, Hochheim, Germany.
| | - Bruno Bembi
- Regional Coordinator Centre for Rare Diseases, Academic Hospital Santa Maria Della Misericordia, Udine, Italy
| | | | | | | | - Stephanie Grunewald
- Metabolic Department, Great Ormond Street Hospital NHS Foundation Trust, Institute for Child Health, NIHR Biomedical Research Centre UCL, London, UK
| | - Sabine Grønborg
- Centre for Inherited Metabolic Diseases, Copenhagen University Hospital (Rigshospitalet), Copenhagen, Denmark
| | - Bénédicte Héron
- Reference Centre for Lysosomal Disease, Trousseau University Hospital, Paris, France
| | - Esther M Maier
- Dr. Von Hauner Children's Hospital, University of Munich, Munich, Germany
| | - Agathe Roubertie
- Institute of Neurosciences, University Hospital of Montpellier, Montpellier, France
| | | | | | - Simon Day
- Clinical Trials Consulting and Training Limited, Buckingham, UK
| | - Tara Symonds
- Clinical Outcomes Solutions Limited, Folkestone, UK
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Lupica A, Di Stefano V, Gagliardo A, Iacono S, Pignolo A, Ferlisi S, Torrente A, Pagano S, Gangitano M, Brighina F. Inherited Neuromuscular Disorders: Which Role for Serum Biomarkers? Brain Sci 2021; 11:398. [PMID: 33801069 DOI: 10.3390/brainsci11030398] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2021] [Revised: 03/08/2021] [Accepted: 03/18/2021] [Indexed: 12/12/2022] Open
Abstract
Inherited neuromuscular disorders (INMD) are a heterogeneous group of rare diseases that involve muscles, motor neurons, peripheral nerves or the neuromuscular junction. Several different lab abnormalities have been linked to INMD: sometimes they are typical of the disorder, but they usually appear to be less specific. Sometimes serum biomarkers can point out abnormalities in presymtomatic or otherwise asymptomatic patients (e.g., carriers). More often a biomarker of INMD is evaluated by multiple clinicians other than expert in NMD before the diagnosis, because of the multisystemic involvement in INMD. The authors performed a literature search on biomarkers in inherited neuromuscular disorders to provide a practical approach to the diagnosis and the correct management of INMD. A considerable number of biomarkers have been reported that support the diagnosis of INMD, but the role of an expert clinician is crucial. Hence, the complete knowledge of such abnormalities can accelerate the diagnostic workup supporting the referral to specialists in neuromuscular disorders.
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Patterson MC, Lloyd-Price L, Guldberg C, Doll H, Burbridge C, Chladek M, íDali C, Mengel E, Symonds T. Validation of the 5-domain Niemann-Pick type C Clinical Severity Scale. Orphanet J Rare Dis 2021; 16:79. [PMID: 33579322 PMCID: PMC7881637 DOI: 10.1186/s13023-021-01719-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Accepted: 02/01/2021] [Indexed: 11/29/2022] Open
Abstract
Background Niemann-Pick disease type C (NPC) is an ultra-rare, progressive, genetic disease leading to impaired lysosomal function and neurodegeneration causing serious morbidity and shortened life expectancy. The Niemann-Pick type C Clinical Severity Scale (NPCCSS) is a 17 domain, disease-specific, clinician-reported outcome measure of disease severity and progression. An abbreviated 5-domain NPCCSS scale has been developed (measuring Ambulation, Swallow, Cognition, Speech, and Fine Motor Skills) and the scale reliability has been established. Additional psychometric properties and meaningful change of the scale need, however, to be assessed. Methods Mixed method studies were conducted to ascertain which NPCCSS domains were most important, as well as to explore meaningful change: 1) surveys in caregivers/patients (n = 49) and 2) interviews with clinicians (n = 5) as well as caregivers/patients (n = 28). Clinical trial data (n = 43) assessed construct validity and meaningful change through an anchor-based approach. Results Domains identified as most important by clinicians, caregivers, and patients (independent of current age, age of onset, and disease severity) were Ambulation, Swallow, Cognition, Speech, and Fine Motor Skills, indicating content validity of the 5-domain NPCCSS. Criterion validity was shown with the 5-domain NPCCSS being highly correlated with the 17-item NPCCSS total score (excluding hearing domains), r2 = 0.97. Convergent validity was demonstrated against the 9 Hole Peg Test, r2 = 0.65 (n = 31 patients), and the Scale for Assessment and Rating of Ataxia (SARA), r2 = 0.86 (n = 49 patients). Any change was seen as meaningful by patients/caregivers across domains. Meaningful change using trial data and interviews with NPC experts (n = 5) and patients/caregivers (n = 28) suggested that a 1-category change on a domain is equivalent to 1-point change or greater in the 5-domain NPCCSS total score. Conclusions Qualitative and quantitative data support content and construct validity of the 5-domain NPCCSS score as a valid endpoint in NPC trials. A 1-category change on any domain is equivalent to 1-point change or greater in the 5 domain NPCCSS total score, representing a clinically meaningful transition and reflecting loss of complex function and increased disability. Trial registration NCT02612129. Registered 23 November 2015, https://clinicaltrials.gov/ct2/show/NCT02612129
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Affiliation(s)
- Marc C Patterson
- Mayo Clinic Children's Center, 200 1st St SW, Rochester, MN, 55905, USA.
| | | | | | - Helen Doll
- Clinical Outcomes Solutions, Folkestone, Kent, UK
| | | | | | | | - Eugen Mengel
- SphinCS GmbH, Institute of Clinical Science for LSD, Hochheim, Germany
| | - Tara Symonds
- Clinical Outcomes Solutions, Folkestone, Kent, UK
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