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Table 1 Algorithm for phenylalanine (Phe) intake adjustments according to mean Phe concentrations

From: Efficacy, safety and population pharmacokinetics of sapropterin in PKU patients <4 years: results from the SPARK open-label, multicentre, randomized phase IIIb trial

Mean Phe concentration, μmol/L Phe intake adjustment
At Week 2
 0–300 Increase by 5 mg/kg/day
 301–359 No adjustment required
 360–∞ No adjustment required, but monitor concentration at next visit
Post-Week 2
 0–180 Increase by 15 mg/kg/day
 181–240 Increase by 10 mg/kg/day
 241–300 Increase by 5 mg/kg/day
 301–359 No change in dietary Phe intake
 360–∞ Determine if the subject had one or more previous dietary Phe intake increases
• If so, remove the dietary Phe in the order that it was previously increased, beginning with the amount of the last increase
• If not, no adjustment required
 360–1199 If this is first occasion at this concentration, monitor concentration at the next visit and if second occasion is at this concentration, provide dietary counseling
 1200–∞ If this is first occasion at this concentration, provide dietary counseling and monitor concentration at the next visit and if second occasion is at this concentration, provide dietary counseling and terminate from the trial