A Study of Two Fabrazyme (Agalsidase Beta) Dosing Regimens in Treatment-naïve, Male Pediatric Patients Without Severe Symptoms

Inclusion criteria

• The participant and/or participant's parent(s)/legal guardian(s) must provide written informed assent/consent prior to any protocol-related procedures being performed.
• The participant must had a confirmed diagnosis of Fabry disease as documented by leukocyte α-Galactosidase A (αGAL) activity of <4 nmol/hr/mg leukocyte (preferred assay; resulted from a central laboratory). If the leukocyte αGAL activity assay was difficult to obtain, the participant might be enrolled based on documented plasma αGAL <1.5 nmol/hr/mL, with the agreement of the Medical Monitor (resulted from a central laboratory).
• The participant must had evidence of globotriaosylceramide (GL-3) accumulation as documented by plasma GL-3 (>7.0 µg/mL) or urinary GL-3 (>0.3 mg GL-3/mmol creatinine) levels (results from a central laboratory).
• The participant must be male ≥5 and ≤18 years of age.

Exclusion criteria

• Participant had albuminuria (first morning void urinary albumin/creatinine ratio >30 mg/g on at least 2 out of 3 consecutive samples, each at least 1 week apart).
• Participant had a Glomerular Filtration Rate (GFR) by iohexol <90 L/min/1.73m^2. In case of properly documented low protein intake, values as low as 80 mL/min/1.73 m^2 might be acceptable, after consultation with the Medical Monitor.
• Participant had documented evidence of stroke or transient ischemic attack (TIA), or if a brain magnetic resonance imaging (MRI) had been performed, bright lesions >2 mm on T2- or fluid attenuated inversion recovery (FLAIR)- weighted images within the white matter or the basal ganglia.
• Participant had severe and recurrent acroparesthesia, judged by the physician as frequent (more than once a week) pain episodes for at least 3 months that influenced daily activities, irrespective of medication.
• Participant had an end-diastolic left ventricular posterior wall thickness (LVPWTd) and/or an end-diastolic interventricular septum thickness (IVSTd)≥2 standard deviations (SD) compared to normal (based on body surface area [BSA] normal ranges from Kampmann, et al 2000) as read at the study site.
• Participant had received prior treatment specific to Fabry Disease.
• Participant had participated in a study employing an investigational drug within 30 days of the start of their participation in this study.
• Participant had any medical condition or extenuating circumstance, which in the opinion of the Study Investigator, could interfere with study compliance.
• Participant had any medical condition or extenuating circumstance, for example diabetes mellitus, which in the opinion of the Study Investigator, could interfere with the interpretation of study results.
• Participant was on treatment with angiotensin converting enzyme inhibitors/angiotensin receptor blockers (ACEIs/ARBs).
• Participant had any contra-indication mentioned in the labeling of Fabrazyme and/or iohexol (Omnipaque).
• Participant or parent(s)/legal guardian(s) was unwilling to comply with the requirements of the protocol.