| E.1 Medical condition or disease under investigation | 
| E.1.1 | Medical condition(s) being investigated  |  | 
| E.1.1.1 | Medical condition in easily understood language  | 
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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  | 24.1 | 
 
| E.1.2 | Level  | PT | 
 
| E.1.2 | Classification code  | 10016016 | 
 
| E.1.2 | Term  | Fabry's 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  | 
| To assess the effect of venglustat on neuropathic or abdominal pain in adult Fabry disease patients who are treatment-naïve or untreated for at least 6 months prior to screening | 
 
 
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| E.2.2 | Secondary objectives of the trial  | 
- To assess the effect of venglustat on plasma globotriaosylsphingosine (lyso-GL-3) levels - To evaluate the effect of venglustat on symptoms of Fabry disease - To assess the safety and tolerability of venglustat in patients with Fabry disease - To evaluate the pharmacokinetics (PK) of venglustat in patients with Fabry disease | 
 
 
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| E.2.3 | Trial contains a sub-study  |  No  | 
| E.3 | Principal inclusion criteria  | 
- Male and female adult patients 18 year of age or older, who have had a previously confirmed diagnosis of Fabry disease and a history of clinical symptoms of Fabry disease - Patients who are treatment-naïve or without prior treatment with an approved or experimental therapy for Fabry disease within at least 6 months prior to screening. - Elevated plasma globotriaosylsphingosine (lyso GL 3) at screening, or a previous biopsy of any organ that shows deposition of GL 3. - Average score of ≥3 (0=no symptom, 10=symptom as bad as you can imagine) on neuropathic pain in upper extremities (item 1), and/or neuropathic pain in lower extremities (item 5) and/or abdominal pain (item 10), as measured by the Fabry Disease Patient-Reported Outcome (FD PRO) at screening. - Contraception for male or female participants: not pregnant or breastfeeding; no sperm donating for male participant. - A signed informed consent must be provided prior to any study-related procedures. 
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| E.4 | Principal exclusion criteria | 
- Any manifestations of Fabry disease that preclude placebo administration. - History of transient ischemic attack, stroke, myocardial infarction, heart failure, major cardiovascular surgery, or kidney transplantation. - History of ongoing clinically significant cardiac arrhythmia or prior or ongoing treatment for the above. - Patients with hepatitis C, HIV, or hepatitis B infection. - Neuropathic pain in upper or lower extremities, or abdominal pain not related to Fabry disease. - History of seizures currently requiring treatment. - Uncontrolled hypertension over the past 12 months prior to screening. - Estimated glomerular filtration rate <60 mL/min/1.73m2. - Presence of severe depression as measured by Beck’s Depression Inventory (BDI)-II >28 and/or a history of an untreated, unstable major affective disorder within 1 year of the screening visit. - Positive SARS-CoV-2 virus test within 2 weeks of enrollment, or COVID 19 requiring hospitalization within 6 months of enrollment. - Moderate to severe hepatic impairment. - History of drug and/or alcohol abuse. - History of or active hepatobiliary disease. - Liver enzymes (alanine aminotransferase (ALT)/aspartate aminotransferase (AST)) or total bilirubin >2 times the upper limit of normal (ULN). - Cortical cataract ≥one-quarter of the lens circumference (Grade cortical cataract [COR-2]) or a posterior subcapsular cataract ≥2 mm (Grade posterior subcapsular cataract [PSC-2]) at the time of screening. - Chronic regimen of potentially cataractogenic medications. - Initiation of chronic treatment for pain, or change in pain medication regimen, within 3  months prior to randomization. - Strong or moderate inducers or inhibitors of cytochrome P450 CYP3A per FDA classification within 14 days or 5 half lives, whichever is longer, prior to randomization. 
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| E.5 End points | 
| E.5.1 | Primary end point(s) | 
| Proportion of responders in neuropathic or abdominal pain, as assessed by Fabry Disease Patient-Reported Outcome (FD-PRO), in patients treated with venglustat versus placebo | 
 
 
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| E.5.1.1 | Timepoint(s) of evaluation of this end point | 
| From baseline to 6 month and 12 months | 
 
 
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| E.5.2 | Secondary end point(s) | 
1 - Percent change in plasma globotriaosylsphingosine (lyso-GL-3) 2 - Proportion of responders in tiredness component of FD-PRO 3 - Change in the percentage of days with at least 1 stool reflecting diarrhea (Bristol Stool Form Scale [BSFS] Type 6 or 7) 4 - Number of participants with adverse event (AE) and serious adverse event (SAE) 5 - Change in lens clarity by ophthalmologic examination  6 - Change in Beck Depression Inventory-II (BDI-II) score 7 - Plasma venglustat concentrations at prespecified visits over the study duration 8 - Maximum venglustat plasma concentration (Cmax) 9 - Time to maximum venglustat plasma concentration (tmax) 10 - Area under the venglustat plasma concentration versus time curve from time 0 to 24 hours (AUC0-24) | 
 
 
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| E.5.2.1 | Timepoint(s) of evaluation of this end point | 
For 1 to 10: From baseline to 6 month and 12 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 |  No  | 
| 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) |  No  | 
| 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 |  Yes  | 
| 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
                             |  Yes  | 
| E.8.4 |  The trial involves multiple sites in the Member State concerned  |  No  | 
| E.8.5 | The trial involves multiple Member States |  Yes  | 
| E.8.5.1 | Number of sites anticipated in the EEA | 24 | 
| 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 | 
| Argentina | 
 
| Brazil | 
 
| Canada | 
 
| China | 
 
| Mexico | 
 
| Russian Federation | 
 
| Turkey | 
 
| Ukraine | 
 
| Austria | 
 
| Denmark | 
 
| Finland | 
 
| France | 
 
| Norway | 
 
| Poland | 
 
| United Kingdom | 
 
| Bulgaria | 
 
| Netherlands | 
 
| Romania | 
 
| Germany | 
 
| Greece | 
 
| Italy | 
 
 
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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 |  | 
| E.8.9.1 | In the Member State concerned months | 44 | 
| E.8.9.1 | In the Member State concerned days |  | 
| E.8.9.2 | In all countries concerned by the trial months | 44 |