Study of the Effects of Oral AT1001 (Migalastat Hydrochloride) in Patients With Fabry Disease

Study Overview
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Brief Summary
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The primary objective of this study was to compare the effect of migalastat (123 milligrams [mg] of migalastat [equivalent to 150 mg of migalastat hydrochloride]) (migalastat) versus placebo on kidney globotriaosylceramide (GL-3).

Detailed Description
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This double-blind, randomized, placebo-controlled study was conducted in 67 participants at 46 sites worldwide. The study consisted of 2 stages and an optional open-label treatment extension phase: Stage 1 included a screening period of up to 2 months followed by a 6-month treatment period which involved 4 visits to the clinic. Participants were randomized in equal proportions to receive either migalastat or placebo. After completing the 6-month double-blind phase, all participants entered Stage 2 of the study and received migalastat in an open-label manner. Stage 2 treatment lasted for 6 months and involved up to 4 visits to the clinic. Participants who completed both Stage 1 and Stage 2 of the study as scheduled were offered the opportunity to participate in an open-label treatment extension phase with migalastat. The open-label treatment extension phase lasted 12 months and involved 2 visits to the clinic. A follow-up visit was undertaken 1 month following completion or discontinuation from the open-label treatment extension. Participants completing the 12-month open-label treatment extension and providing consent to enter a separate long-term extension were not required to complete this follow-up visit. Study assessments included clinical laboratory tests, 12-lead electrocardiogram, kidney biopsy, kidney function testing, echocardiography, and patient-reported outcomes.

Official Title
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A Double-Blind, Randomized, Placebo-Controlled Study to Evaluate the Efficacy, Safety and Pharmacodynamics of AT1001 in Patients With Fabry Disease and AT1001-Responsive GLA Mutations

Conditions
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Fabry Disease

Intervention / Treatment
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* Drug: migalastat hydrochloride
* Drug: Placebo


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Male or female between the ages of 16 and 74 diagnosed with Fabry disease. Confirmed mutant form of α-galactosidase A shown to be responsive to migalastat in vitro. Participant has never been treated with enzyme replacement therapy (ERT) or has not received ERT for 6 consecutive months or longer before the screening visit for the study. Urine GL-3 ≥4 times the upper limit of normal at screening. Participants taking angiotensin converting enzyme inhibitors or angiotensin receptor blockers must be on a stable dose for a minimum of 4 weeks before the baseline visit. Females who can become pregnant and all males agree to be sexually abstinent or use medically accepted methods of birth control during the study and for 30 days after study completion. Participant is willing and able to provide written informed consent and assent, if applicable. Exclusion Criteria: Participant has undergone or is scheduled to undergo kidney transplantation, or is currently on dialysis. Estimated glomerular filtration rate <30 milliliters per minute per 1.73 meters squared (chronic kidney disease Stage 4 or 5) based on the Modification of Diet in Renal Disease equation at screening. Pregnant or breast-feeding. History of allergy or sensitivity to study medication (including excipients) or other iminosugars (for example, miglustat, miglitol). Participant is treated or has been treated with any investigational drug within 30 days of study start. Participant is currently treated or has ever been treated with migalastat.

Ages Eligible for Study
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Minimum Age: 16 Years
Maximum Age: 74 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Migalastat<br>Migalastat 150-mg capsule taken orally every other day (QOD) for 6 months and an open-label 6-month treatment extension, followed by an optional, 12-month, open-label treatment extension. | Drug: migalastat hydrochloride<br>* Oral capsule QOD<br>* Other names: Migalastat;|
| Placebo Comparator: Placebo<br>Placebo capsule taken orally QOD for 6 months. | Drug: Placebo<br>* Oral capsule QOD<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Percentage Of Participants With At Least A 50% Reduction From Baseline To Month 6 In The Average Number Of Kidney Interstitial Capillary (IC) Globotriaosylceramide (GL-3) Inclusions | Renal biopsies were taken at Baseline and Month 6 (Stage 1). The specimens were evaluated using virtual microscopy. The annotation, scoring, and adjudication of the kidney histology assessments were performed by the Clinical Pathology Endpoints Committee. The number of kidney IC GL-3 inclusions was assessed by 3 renal pathologists who were blinded to treatment assignments, participants' data, and biopsy sequence. One pathologist served as annotator and identified the 300 capillaries on up to 8 slides per specimen to be scored. Two pathologists served as scorers; these pathologists completed the blinded paired assessments. Each pathologist served as annotator/adjudicator for 1/3 of the cases. Paired assessments were undertaken at Baseline and Month 6. Assessments were made using digital images. A responder was defined as a participant with a ≥50% reduction from Baseline to Month 6 in the average number of kidney IC GL-3 inclusions. | Baseline, Month 6 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Percent Change In Kidney IC GL-3 Inclusions From Baseline To Month 6 | Renal biopsies were taken at Baseline and Month 6. The specimens were evaluated using virtual microscopy. The annotation, scoring, and adjudication of the kidney histology assessments were performed by the Clinical Pathology Endpoints Committee. The number of kidney IC GL-3 inclusions was assessed by 3 renal pathologists who were blinded to treatment assignments, participants' data, and biopsy sequence. One pathologist served as annotator and identified the 300 capillaries on up to 8 slides per specimen to be scored. Two pathologists served as scorers; these pathologists completed the blinded paired assessments. Each pathologist served as annotator/adjudicator for 1/3 of the cases. Paired assessments were undertaken at Baseline and Month 6. Assessments were made using digital images. | Baseline, Month 6 | 
| Change From Baseline Through Month 24 In Urine GL-3 Levels | The effect of migalastat versus placebo on urine GL-3 levels was measured by liquid chromatography-mass spectrometry/mass spectrometry. The 24-hour urine samples were collected at Baseline, Month 6 (Stage 1), Month 12 (Stage 2), and Month 24 (OLE). Results are presented as changes in nanograms (ng)/mg creatinine from Baseline to the end of the 3 stages. | Baseline, Months 6, 12, and 24 | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Amicus Therapeutics, AT1001, Migalastat, Pharmacokinetics, Substrate, Galafold