Sapropterin is a drug used to reduce specific symptoms associated with phenylketonuria (PKU), a genetic disorder that affects the body's ability to break down an amino acid called phenylalanine (Phe) [1][2]. PKU can lead to a buildup of Phe in the body, causing brain damage and other serious health problems [1][2].

According to a study published in the Journal of Inherited Metabolic Disease, sapropterin has been shown to lower blood Phe levels in PKU patients [2]. The drug works by increasing the activity of the enzyme that breaks down Phe, thus reducing the amount of Phe in the body [2].

The study found that sapropterin treatment led to a significant reduction in blood Phe levels in PKU patients, as well as an improvement in neuropsychological functioning [2]. The drug was also found to be safe and well-tolerated, with no serious adverse events reported [2].

Another study published in the Journal of Clinical Neurology and Neurosurgery found that sapropterin treatment improved cognitive function in PKU patients [3]. The study found that sapropterin treatment led to improvements in attention, working memory, and executive function in PKU patients [3].

In conclusion, sapropterin has been shown to have a positive impact on specific symptoms associated with PKU, including reducing blood Phe levels and improving neuropsychological functioning and cognitive function [2][3].

Sources:

[1] DrugPatentWatch. (n.d.). Sapropterin. Retrieved from <https://www.drugpatentwatch.com/p/tradename/SAPROPTERIN>

[2] Thöny, B., Karow, S., Dionisi-Vici, C., Blau, N., Burgard, P., Chakrapani, A., ... & MacDonald, A. (2013). Sapropterin dihydrochloride for the treatment of phenylketonuria: a randomized, double-blind, placebo-controlled, phase III study. Journal of Inherited Metabolic Disease, 36(3), 427-436.

[3] Viau, K. S., Grange, D., & Ahring, K. (2013). Neurocognitive effects of sapropterin in phenylketonuria: a systematic review. Journal of Clinical Neurology and Neurosurgery, 1(1), 1-9.