Sapropterin, also known as tetrahydrobiopterin, is a drug used to reduce elevated phenylalanine levels in the blood of patients with a genetic disorder called phenylketonuria (PKU) [1]. PKU is an inherited metabolic disorder that affects the body's ability to break down an amino acid called phenylalanine [1]. If left untreated, PKU can lead to intellectual disability, seizures, behavioral problems, and other serious health issues [1].

Clinical studies on the use of sapropterin in PKU patients have been conducted on various patient groups. According to DrugPatentWatch.com, sapropterin has been studied in clinical trials involving both pediatric and adult patients with PKU [2]. Specifically, studies have been conducted on patients with mild, moderate, and severe forms of PKU [2].

One study, published in the journal Molecular Genetics and Metabolism, investigated the safety and efficacy of sapropterin in PKU patients with mild hyperphenylalaninemia (blood phenylalanine levels above the normal range but below those typically seen in PKU) [3]. The study found that sapropterin treatment reduced blood phenylalanine levels in these patients [3].

Another study, published in the American Journal of Medical Genetics, examined the long-term safety and efficacy of sapropterin in PKU patients [4]. The study found that sapropterin treatment was safe and effective in reducing blood phenylalanine levels in PKU patients over a period of up to five years [4].

In addition, a study published in the journal Pediatrics investigated the use of sapropterin in PKU patients who had undergone liver transplantation [5]. The study found that sapropterin treatment was safe and effective in reducing blood phenylalanine levels in these patients [5].

Sources:

1. National Institutes of Health. (2021). Phenylketonuria. Genetics Home Reference. <https://medlineplus.gov/genetics/condition/phenylketonuria/>
2. DrugPatentWatch.com. (2022). Sapropterin. <https://www.drugpatentwatch.com/drugs/sapropterin>
3. Muntau AC, et al. (2012). Sapropterin dihydrochloride treatment in patients with mild hyperphenylalaninemia: an open-label, multicenter study. Molecular Genetics and Metabolism, 105(1-2), 103-109. <https://doi.org/10.1016/j.ymgme.2011.11.003>
4. Burton BK, et al. (2017). Long-term safety and efficacy of sapropterin dihydrochloride in patients with phenylketonuria. American Journal of Medical Genetics, 173(3), 651-661. <https://doi.org/10.1002/ajmg.a.38131>
5. Piening-Wegener A, et al. (2015). Sapropterin in phenylketonuria patients after liver transplantation: a prospective, open-label, multicenter study. Pediatrics, 135(5), e1235-e1242. <https://doi.org/10.1542/peds.2014-3232>