| E.1 Medical condition or disease under investigation | 
| E.1.1 | Medical condition(s) being investigated  | 
| Niemann Pick disease type C | 
 
 
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| E.1.1.1 | Medical condition in easily understood language  | 
| Niemann-Pick Type C is a rare and inherited disease in which quantities of fatty substances accumulate in the brain and other organs. The brain, central nervous system, liver and spleen are affected. | 
 
 
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| E.1.1.2 | Therapeutic area  | Diseases [C] - Congenital, Hereditary, and Neonatal Diseases and Abnormalities [C16] | 
| MedDRA Classification | 
| E.1.2 Medical condition or disease under investigation | 
| E.1.2 | Version  | 20.0 | 
 
| E.1.2 | Level  | PT | 
 
| E.1.2 | Classification code  | 10029403 | 
 
| E.1.2 | Term  | Niemann-Pick disease | 
 
| E.1.2 | System Organ Class  | 10010331 - Congenital, familial and genetic disorders | 
 
 
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| E.1.3 | Condition being studied is a rare disease  |  Yes  | 
| E.2 Objective of the trial | 
| E.2.1 | Main objective of the trial  | 
MAIN STUDY: To evaluate therapeutic response to arimoclomol versus placebo, both in addition to best available standard of care, at 12 months. 
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| E.2.2 | Secondary objectives of the trial  | 
MAIN STUDY: •To evaluate the therapeutic response to arimoclomol through clinical, biological and imaging assessments at 6 and 12 months; •To evaluate the long term therapeutic response (clinical and biological assessments) at 18 months  and every 6 months thereafter until End of Extension Phase at 60 months and hereafter annually until study end; •To evaluate the safety of arimoclomol. 
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| E.2.3 | Trial contains a sub-study  |  Yes  | 
| E.2.3.1 | Full title, date and version of each sub-study and their related objectives | 
PAEDIATRIC SUBSTUDY: (within the same protocol, under the same title) Primary: • To evaluate the safety and tolerability of arimoclomol in patients aged 6 to <24 months at study enrollment. Secondary: • To evaluate the therapeutic response to arimoclomol in patients aged 6 to <24 months at study enrollment through clinical, biological and imaging assessments. • To assess the PK [AUC0-8,SS] of arimoclomol, and if relevant also of metabolites in patients aged 6 to <24 months at study enrollment. 
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| E.3 | Principal inclusion criteria  | 
•	Diagnosis of NPC1 or NPC2; •	NPC diagnosis confirmed by: o	Genetically confirmed (deoxyribonucleic acid [DNA] sequence analysis) by mutations in both alleles of NPC1 or NPC2, OR Mutation in only one allele of NPC1 or NPC2 plus either positive filipin staining or elevated cholestane triol/oxysterols (>2 x upper limit of normal [ULN]). • Main study: Males and females aged from 2 years to 18 years and 11 months; • Paediatric substudy: Males and females aged 6 to <24 months; with a cap of maximum 3 patients above 18 months • Treated or not treated with miglustat; o	Main study: If a patient is under prescribed treatment with miglustat, it has to be under stable dose of the medication for at least 6 continuous months prior to inclusion in the CT ORZY NPC 002 study; o	Main study: If a patient has been discontinued from prescribed treatment with miglustat, they must have been discontinued for at least 3 continuous months prior to inclusion in the CT-ORZY-NPC-002 study; o	Paediatric substudy: If a patient is on prescribed treatment with miglustat, the dose must have been stable for at least 1 month prior to inclusion in the paediatric substudy; o	Paediatric substudy: If a patient has been discontinued from prescribed treatment with miglustat, they must have been discontinued for at least 1 month prior to inclusion in the paediatric substudy. 
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| E.4 | Principal exclusion criteria | 
Main exclusion criteria: • Severe liver insufficiency (defined as hepatic laboratory parameters, AST and/or ALT greater than three-times the ULN for age and gender [central laboratory assessment]); • Renal insufficiency, with serum creatinine level greater than 1.5 times the ULN (central laboratory assessment); • Paediatric substudy: Patients with known causes of active liver disease or prolonged icterus or malformation of organs other than NPC (e.g. Gaucher disease, chronic viral hepatitis, Gilbert syndrome, blood group incompatibilities); • Paediatric substudy: Patient was born before 37 weeks gestation; • Paediatric substudy: Patient weight <5 kg at study enrolment; • Paediatric substudy: Patient was diagnosed with severe intra-uterine growth restriction. | 
 
 
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| E.5 End points | 
| E.5.1 | Primary end point(s) | 
•	Change in the NPC disease severity based on the 5 domain NPCCSS scores (ambulation, speech, swallow, fine motor skills and cognition) from baseline (Visit 1) to 12 months; •	Safety and tolerability. 
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| E.5.1.1 | Timepoint(s) of evaluation of this end point | 
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| E.5.2 | Secondary end point(s) | 
Key Secondary Endpoints: •	Responder analysis of patient’s CGI-I score remains stable or shows improvement at 12 months (for the FDA submission, this endpoint is considered co-primary); •	Responder analysis of patient’s 5 domain NPCCSS score remains stable or improves at 12 months compared to baseline; •	Time to worsening (as defined by reaching the minimal clinically important difference [MCID] on patient's 5 domain NPCCSS).  The MCID will be determined and documented prior to unblinding the study;  •	Proportion of patients worsening (as defined by reaching the MCID on patient’s 5 domain NPCCSS) at 6 and 12 months •	Change in full scale NPCCSS score apart from hearing domains (i.e. Hearing and Auditory Brainstem Response) at 12 months. 
 Other Secondary Endpoints: • Change in 5 domain NPCCSS score at 6 and 18 months and every 6 months thereafter until End of Extension Phase at 60 months; • Change in full scale NPCCSS score apart from hearing domains(i.e. Hearing and Auditory Brainstem Response) at 6 and 18 months and every 6 months thereafter until End of Extension Phase at 60 months; • Responder analysis of the CGI-I score remains stable or shows improvement at 6 and 18 months and every 6 months thereafter until End of Extension Phase at 60 months; • Responder analysis of 5 domain NPCCSS score remains stable or improves at 6 and 18 months and every 6 months thereafter until End of Extension Phase at 60 months compared to baseline; • Proportion of patients worsening (as defined by reaching the MCID on patient's 5 domain NPCCSS) at 18 months and every 6 months thereafter until End of Extension Phase at 60 months; • Changes in each individual domain of the NPCCSS at 6, 12 and 18 months and every 6 months thereafter until End of Extension Phase at 60 months; • Change in the Niemann Pick type C Clinical Database (NPC-cdb) score (modified Stampfer Score" [Stampfer et al., 2013]) at 6, 12 and 18 months and every 6 months thereafter until End of Extension Phase at 60 months; • Change in Quality of Life (EQ-5D-Y) at 6, 12 and 18 months and every 6 months thereafter until End of Extension Phase at 60 months; • Change in the SARA score at 6, 12 and 18 months and every 6 months thereafter until End of Extension Phase at 60 months; • Change in the 9HPT time at 6, 12 and 18 months, and every 6 months thereafter until End of Extension Phase at 60 months; • CGI-S score at 6, 12 and 18 months and every 6 months thereafter until End of Extension Phase at 60 months; • CGI-I score at 6, 12 and 18 months and every 6 months thereafter until End of Extension Phase at 60 months. 
 PAEDIATRIC SUBSTUDY: • Clinical signs and symptoms captured through physical examination; • Change from baseline in patient weight and height; • Change in Bayley III score: Developmental delay scoring. | 
 
 
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| E.5.2.1 | Timepoint(s) of evaluation of this end point | 
| Timepoints will be at 6 months, 12 months, 18 months and every 6 months thereafter until End of Extension Phase at 60 months | 
 
 
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| E.6 and E.7 Scope of the trial | 
| E.6 | Scope of the trial | 
| E.6.1 | Diagnosis |  No  | 
| E.6.2 | Prophylaxis |  No  | 
| E.6.3 | Therapy |  Yes  | 
| E.6.4 | Safety |  Yes  | 
| E.6.5 | Efficacy |  Yes  | 
| E.6.6 | Pharmacokinetic |  Yes  | 
| E.6.7 | Pharmacodynamic |  No  | 
| E.6.8 | Bioequivalence |  No  | 
| E.6.9 | Dose response |  No  | 
| E.6.10 | Pharmacogenetic |  No  | 
| E.6.11 | Pharmacogenomic |  No  | 
| E.6.12 | Pharmacoeconomic |  No  | 
| E.6.13 | Others |  No  | 
| E.7 | Trial type and phase | 
| E.7.1 | Human pharmacology (Phase I) |  No  | 
| E.7.1.1 | First administration to humans |  No  | 
| E.7.1.2 | Bioequivalence study |  No  | 
| E.7.1.3 | Other |  No  | 
| E.7.1.3.1 | Other trial type description |  | 
| E.7.2 | Therapeutic exploratory (Phase II) |  Yes  | 
| E.7.3 | Therapeutic confirmatory (Phase III) |  Yes  | 
| E.7.4 | Therapeutic use (Phase IV) |  No  | 
| E.8 Design of the trial | 
| E.8.1 | Controlled |  Yes  | 
| E.8.1.1 | Randomised |  Yes  | 
| E.8.1.2 | Open |  No  | 
| E.8.1.3 | Single blind |  No  | 
| E.8.1.4 | Double blind  |  Yes  | 
| E.8.1.5 | Parallel group |  No  | 
| E.8.1.6 | Cross over  |  No  | 
| E.8.1.7 | Other |  No  | 
| E.8.2 |  Comparator of controlled trial | 
| E.8.2.1 | Other medicinal product(s) |  No  | 
| E.8.2.2 | Placebo  |  Yes  | 
| E.8.2.3 | Other |  No  | 
| E.8.2.4 | Number of treatment arms in the trial | 2 | 
| E.8.3 | 
                                The trial involves single site in the Member State concerned
                             |  No  | 
| E.8.4 |  The trial involves multiple sites in the Member State concerned  |  Yes  | 
| E.8.4.1 | Number of sites anticipated in Member State concerned | 2 | 
| E.8.5 | The trial involves multiple Member States |  Yes  | 
| E.8.5.1 | Number of sites anticipated in the EEA | 15 | 
| E.8.6 Trial involving sites outside the EEA | 
| E.8.6.1 | Trial being conducted both within and outside the EEA |  Yes  | 
| E.8.6.2 | Trial being conducted completely outside of the EEA |  No  | 
| E.8.6.3 | If E.8.6.1 or E.8.6.2 are Yes, specify the regions in which trial sites are planned | 
| Switzerland | 
 
| United States | 
 
 
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| E.8.7 | Trial has a data monitoring committee |  Yes  | 
| E.8.8 | 
                        Definition of the end of the trial and justification where it is not the last
                        visit of the last subject undergoing the trial
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| E.8.9 Initial estimate of the duration of the trial | 
| E.8.9.1 | In the Member State concerned years | 5 | 
| E.8.9.1 | In the Member State concerned months | 0 | 
| E.8.9.1 | In the Member State concerned days | 0 | 
| E.8.9.2 | In all countries concerned by the trial years | 5 | 
| E.8.9.2 | In all countries concerned by the trial months | 0 | 
| E.8.9.2 | In all countries concerned by the trial days | 0 |