I undersøgelsen af patienterne med BH4- defekt sås der en forbedring af koncentrationen af fenylalanin i blodet og af andre sygdomstegn hos de patienter, der tog sapropterindihydrochlorid.
In the studies of patients with BH4 deficiency, patients showed an improvement in blood phenylalanine levels and other markers of the disease when they were taking sapropterin dihydrochloride.