Study TKT024EXT was conducted in 2 phases. The first phase ("Phase I") was 2 years (104 weeks) in duration and consisted of weekly infusions of IV idursulfase (0.5 mg/kg), and the collection of patients' safety and clinical outcomes. Week 105 defined the beginning of the second phase of the study. The second phase ("Phase II") consisted of weekly infusions of IV idursulfase (0.5 mg/kg) and the monitoring of patients for safety (via collection of adverse events, concomitant medications, and vital signs). Study completion was defined as the time a patient either transitioned to commercially available idursulfase or discontinued this study.
Idursulfase was administered to patients as a continuous IV infusion at a dose of 0.5 mg of protein per kg of body weight (0.5 mg/kg). Final evaluations from Study TKT024, the one-year predecessor Phase 2/Phase 3 registration study, served as the baseline assessments for the TKT024EXT study. Forced vital capacity (FVC) and the 6-minute walk test (6MWT) continued to be the primary clinical outcomes of TKT024EXT study. Efficacy outcomes were evaluated over the course of 2 years and were determined at 4-month intervals during the first year (ie, Weeks 18, 36, and 53) and at 6-month intervals in the second year (ie, Weeks 79 and 105). Safety outcomes were assessed throughout the duration of the study. The safety and clinical testing performed in the TKT024EXT study were identical to those performed in the double-blind phase of Study TKT024.
