Der ved øges eller genoprettes den oxidative fenylalanin metabolisme til et niveau, der er tilstrækkeligt til at reducere eller vedholde fenylalanin niveauet i blodet, forebygge eller mindske yderligere fenylalaninophobning samt øge tolerancen over for indtaget af fenylalanin via kosten.
The rationale for administration of Kuvan in patients with BH4-responsive PKU is to enhance the activity of the defective phenylalanine hydroxylase and thereby increase or restore the oxidative metabolism of phenylalanine sufficient to reduce or maintain blood phenylalanine levels, prevent or decrease further phenylalanine accumulation, and increase tolerance to phenylalanine intake in the diet.