NCT01376908.

Methods	Allocation: randomized Endpoint classification: safety and efficacy study Intervention model: parallel assignment Masking: open label Primary purpose: treatment
Participants	Children less than 4 years old with PKU
Interventions	Kuvan, phe‐restricted diet
Outcomes	Dietary phe tolerance after 26 weeks, Levels of blood phe, Change from baseline in dietary phe tolerance after 26 weeks, number of participants with adverse events after 26 weeks and 3 years
Notes	Participants randomized into phe‐restricted diet only and Kuvan + phe‐restricted diet groups. Trial period is 26 weeks, with an extension period of 3 years.

Phe: phenylalanine
 PKU: phenylketonuria