Study to Compare the Efficacy and Safety of Oral AT1001 and Enzyme Replacement Therapy in Patients With Fabry Disease

This was a Phase 3, randomized, open-label, active-controlled study to evaluate the efficacy
and safety of 150 milligrams (mg) of migalastat hydrochloride (migalastat) (equivalent to 123
mg of migalastat) once every other day (QOD) and ERT in male and female participants with
Fabry disease who were receiving ERT and who have an α Gal-A mutation that is amenable to
migalastat, based on the clinical trial HEK assay. This was a 2-part study. Part 1, the
18-month randomized phase, evaluated participants who received either migalastat 150 mg QOD
or ERT per prescribing physicians' instructions for efficacy and safety. Part 2, the optional
12-month open-label extension (OLE) phase in which all participants received migalastat, also
explored efficacy and safety. For Part 2, all participants who received ERT in Part 1 were
given migalastat. Data presented in this posting include efficacy data from the 18-month
randomized period and safety data from the entire study (18-month randomized period and
12-month optional OLE [total of 30 months]).

Inclusion Criteria:

- Male or female between the ages of 16 and 74 diagnosed with Fabry disease

- Confirmed α Gal-A mutation that is amenable to migalastat, based on the clinical trial
HEK assay

- Participant has been on ERT for at least 12 months before screening/baseline

- Dose level and regimen of ERT have been stable for 3 months before screening/baseline
and is at least 80% of the currently labeled dose and regimen for this time period

- Glomerular filtration rate (GFR) ≥ 30 milliliter (mL)/minute (min) /1.73 m^2

- Participants taking angiotensin converting enzyme inhibitors or angiotensin receptor
blockers must be on a stable dose for at least 4 weeks before screening/baseline

- Women who can become pregnant and all men agree to be sexually abstinent or use
medically accepted methods of birth control throughout the duration of the study and
for up to 30 days after last dose of study medication

- 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 any
other solid organ transplantation

- Participant is on regular dialysis that is specifically for the treatment of chronic
kidney disease

- Participant has had a documented transient ischemic attack, stroke, unstable angina,
or myocardial infarction within the 3 months before screening/baseline

- Participant has clinically significant unstable cardiac disease in the opinion of the
investigator (for example, cardiac disease requiring active management, such as
symptomatic arrhythmia, unstable angina, or New York Heart Association (NYHA) class
III or IV congestive heart failure)

- Pregnant or breast-feeding

- History of allergy or sensitivity to study medication (including excipients) or other
iminosugars (for example, miglustat, miglitol)

- Participant has absolute contraindication to iohexol and/or inability to undergo
iohexol GFR testing

- Participant requires treatment with Glyset® (miglitol), or Zavesca® (miglustat)

- Participant received any investigational/experimental drug, biologic or device within
30 days of screening/baseline

- Any intercurrent illness or condition that may preclude the participant from
fulfilling the study requirements or suggests to the investigator that the participant
may have an unacceptable risk by participating in this study