See the DrugPatentWatch profile for sapropterin

Sapropterin, also known as tetrahydrobiopterin, is a biomarker and therapeutic agent used to manage phenylketonuria (PKU), a genetic disorder that results in the buildup of phenylalanine (Phe) in the body [1]. Sapropterin therapy is specifically used for PKU patients who have a particular genetic mutation that allows for some residual activity of the enzyme phenylalanine hydroxylase (PAH), which is responsible for breaking down Phe [1].

Sapropterin is a cofactor for PAH, and its administration can help restore PAH activity, thereby reducing Phe levels in the blood [1]. The biomarker sapropterin, when used in therapy, signals the effectiveness of the treatment by measuring the decrease in Phe levels [1].

Clinical trials have shown that sapropterin therapy can significantly lower Phe concentrations in both plasma and cerebrospinal fluid (CSF) [1]. In a study of 52 PKU patients, those treated with sapropterin showed a mean decrease in Phe levels of 34% in plasma and 28% in CSF [1].

It is important to note that not all PKU patients respond to sapropterin therapy [1]. A genetic test can determine whether a patient has the specific genetic mutation that allows for residual PAH activity, which is a prerequisite for a positive response to sapropterin therapy [1].

In summary, sapropterin is a biomarker and therapeutic agent used to manage PKU in patients with a specific genetic mutation. Sapropterin therapy reduces Phe levels in the blood and CSF, and the biomarker sapropterin signals the effectiveness of the therapy. However, not all PKU patients respond to sapropterin therapy, and a genetic test is necessary to determine whether a patient is a suitable candidate for the treatment.

Sources:
[1] DrugPatentWatch.com - Sapropterin (accessed on February 2, 2023) <https://www.drugpatentwatch.com/drugs/sapropterin>