Replagal Enzyme Replacement Therapy for Children With Fabry Disease

Overview

Primary Objective(s): * To assess the safety of Replagal at a dose of 0.2 mg/kg administered over 40 (+/-10) minutes in children with Fabry disease * To assess the effect of Replagal on heart rate variability in patients 7 to 17 years of age Secondary Objective(s): * To determine the pharmacokinetics of Replagal at baseline and after the initiation of enzyme replacement therapy (ERT) * To determine exploratory measurements of efficacy including renal function (ie, estimated glomerular filtration rate \[eGFR\] and creatinine clearance), clinical outcomes (in Cohorts 1 and 2), and sweating and left ventricular mass index (LVMI) (Cohort 1, Phase 1 only)

TKT029 is an open label multi-center study to assess the safety of enzyme replacement therapy with Replagal (agalsidase alfa) in children with Fabry disease, who have completed 6 months of agalsidase alfa therapy in study TKT023 (Cohort 1) or who are treatment-naïve (Cohort 2) and meet all inclusion/exclusion criteria of this study. The study will consist of every other week treatment with Replagal for 52 weeks, with periodic reassessments by Shire HGT for continuation of the study beyond 52 weeks. A decision on the part of the study sponsor to terminate the study may be made at any time. In Cohort 1, safety and clinical measurement assessments performed during Week 25 or 26 of Study TKT023 served as the baseline assessments for TKT029. Patients in Cohort 1 began treatment with Replagal manufactured using a roller bottle process (Replagal RB); this portion of treatment is denoted as Cohort 1, Phase 1. Safety evaluation visits for Cohort 1, Phase 1 were to be performed at Weeks 13, 25, 55, and every 26 weeks thereafter until the patient discontinued from the study or transitioned to treatment with Replagal manufactured using a bioreactor process (Replagal AF). The transition to Replagal AF marked the restart of the study clock and was denoted as Cohort 1, Phase 2. Safety evaluation visits for Cohort 1, Phase 2 will be performed at Weeks 1, 13, 25, 55, and every 26 weeks thereafter until the patient discontinues from or the sponsor terminates the study. Patients in Cohort 2 will receive treatment with Replagal AF only; therefore there is only 1 study phase for these patients. Screening assessments performed at Week -1 will serve as the baseline assessments for this study. Safety evaluation visits for Cohort 2 will be performed at Weeks 13, 25, 37, 55 and every 26 weeks thereafter until the patients discontinues from or the sponsor terminates the study. The final study visit for both cohorts will follow 30 days after the study study drug infusion, at which time a final safety evaluation will be performed. Patients who complete the study will be interviewed by telephone 30 days after their last study infusion for resolution of any outstanding adverse events (AEs) or concomitant medication changes. Any patient who withdraws early from the study will have a final study visit 30 days after the last study drug infusion, at which time a final safety evaluation will be performed.