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

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.

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.