Study to evaluate the safety, tolerability, pharmacokinetics, and pharmacodynamics of migalastat hydrochloride (HCl) (migalastat) in participants with Fabry disease.

This was a Phase 2, open-label study in male participants with Fabry disease. All participants who met initial eligibility criteria underwent a 28-day screening period, including a 14-day run-in with migalastat (150 milligrams [mg] migalastat once a day [QD] from Days -28 to -15) to assess eligibility for entering the treatment period of the study. Participants who entered the treatment period were required to have α-galactosidase A (α-Gal A) activity responsive to migalastat.

Fifteen participants received at least 1 dose of study drug, however, 6 of these participants did not demonstrate α-Gal A activity responsive to migalastat and were thus screen failures (these participants are hereafter referred to as "dosed screen failures") due to not meeting all inclusion criteria for treatment. Therefore, 9 participants were enrolled into the treatment period (these participants are hereafter referred to as "eligible-enrolled").

Eligible-enrolled participants (those who satisfied the criteria for inclusion in the study) received escalating doses of migalastat twice a day (BID) for 6 weeks (Days 1 to 42), followed by 6 weeks at 1 dose level BID (Days 43 to 84) during the treatment period. Participants could then opt to participate in the extension period. The study consisted of 2 optional extension periods, the first through Week 48 and the second through Week 96. For participants who did not continue into the optional treatment extension, the study included a 2-week follow-up period.

Inclusion Criteria:

• Males between 18 and 55 years of age (inclusive)
• Hemizygous for Fabry disease
• Had a confirmed diagnosis of Fabry disease with a documented missense gene mutation (individual or familial)
• Had enhanceable enzyme activity
• In the judgment of the investigator, were either able to safely suspend ERT throughout the study, or be ERT naive
• Agreed to be sexually abstinent or use a condom with spermicide when engaging in sexual activity during the course of the study and for a period of 30 days following completion of the study
• Were willing and able to sign an informed consent form

Exclusion Criteria:

• History of significant disease other than Fabry disease (for example, end-stage renal disease; Class III or IV heart disease [per the New York Heart Association classification]; current diagnosis of cancer, except for basal cell carcinoma of the skin; diabetes [unless hemoglobin A1c ≤8]; or neurological disease that would have impaired the participant's ability to participate in the study)
• History of organ transplant
• Serum creatinine >2 mg per deciliter on Day -2
• Screening 12-lead electrocardiogram demonstrating corrected QT interval >450 milliseconds prior to dosing
• Taking a medication prohibited by the protocol: Fabrazyme® (agalsidase beta), Replagal™ (agalsidase alfa), Glyset® (miglitol), Zavesca® (miglustat), or any experimental therapy for any indication
• Participated in a previous clinical trial in the last 30 days
• Any other condition, which, in the opinion of the investigator, would jeopardize the safety of the participant or impact the validity of the study results

Eligible-enrolled participants who received at least 1 dose of study drug. 6 participants were dosed screen failures, and were not included in safety, PK, or PD analyses.

Day 1 after dosing through Week 96 (end of extension period)