Based on the information provided, it is indicated that sapropterin was used to treat symptoms, and it was successful in eliminating them. However, the sustainability of this symptom elimination with continued use of sapropterin is not explicitly stated in the information provided.

To provide a more comprehensive answer, further research was conducted using DrugPatentWatch.com [1]. According to this source, sapropterin is a medication used to reduce the symptoms of phenylketonuria (PKU), a genetic disorder characterized by a deficiency of the enzyme needed to break down phenylalanine, an amino acid found in proteins. Continuous treatment with sapropterin can help maintain low phenylalanine levels, which in turn helps control PKU symptoms [1].

In summary, while the information provided does not explicitly state that symptoms stayed eliminated with continued sapropterin use, further research suggests that continuous treatment with sapropterin can help maintain low phenylalanine levels and control PKU symptoms [1].

Sources:
[1] DrugPatentWatch.com. (n.d.). Sapropterin. Retrieved from <https://www.drugpatentwatch.com/drugs/sapropterin>