This Phase 2a, multicenter, open-label, dose-escalation study was designed to assess the safety and biological activity of once-daily (or twice-daily [BID], only for the highest dose level) oral administration of 4 escalating doses of sapropterin dihydrochloride to subjects with Sickle Cell Disease (SCD); 32 subjects were enrolled in the dose-escalation phase of this study. Subjects received oral, once daily (for 2.5, 5, and 10 mg/kg/day) or BID (for 20 mg/kg/day) doses of sapropterin dihydrochloride during a 16-week, dose-escalation period, with dose levels increasing within subjects every 4 weeks, as follows: 2.5, 5, 10, and 20 mg/kg/day. At the highest dose level (20 mg/kg/day), the total dose of sapropterin dihydrochloride was divided, half of the tablets taken in the morning within 1 hour after a meal, and half approximately 12 hours later (or BID) within 1 hour after a meal. The extension phase of this study was terminated.
This Phase 2a, multicenter, open-label, dose-escalation study is designed to assess the safety and biologic activity of daily oral administration of 4 escalating doses of sapropterin dihydrochloride over 16 weeks in subjects with sickle cell disease. During an optional extension phase, the study will assess the safety, tolerability, and efficacy of extended treatment with sapropterin dihydrochloride, for a total of up to 2 years; The extension phase of this study was terminated.