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

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).

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.

Eligibility Criteria:
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.