See the DrugPatentWatch profile for sapropterin

Sapropterin is a medication used to treat phenylketonuria (PKU), a rare genetic disorder that affects the body's ability to break down the amino acid phenylalanine. However, not all patients respond equally to sapropterin treatment. Identifying biomarkers that predict non-response to sapropterin therapy is crucial for optimizing treatment outcomes.

Several studies have investigated potential biomarkers for predicting sapropterin non-response. One such biomarker is the expression of the enzyme phenylalanine hydroxylase (PAH), which is responsible for converting phenylalanine into tyrosine. A study published in the Journal of Inherited Metabolic Disease found that patients with lower PAH activity were more likely to experience a poor response to sapropterin therapy [1].

Another potential biomarker is the level of phenylalanine in the blood. A study published in the Journal of Clinical Biochemistry and Nutrition found that patients with higher phenylalanine levels at the start of sapropterin treatment were more likely to experience a poor response [2].

Additionally, genetic variations in the PAH gene have been linked to sapropterin non-response. A study published in the American Journal of Human Genetics found that patients with certain PAH gene mutations were more likely to experience a poor response to sapropterin therapy [3].

Furthermore, a study published in the Journal of Inherited Metabolic Disease found that patients with higher levels of the protein tyrosine hydroxylase (TPH) were more likely to experience a poor response to sapropterin therapy [4].

In conclusion, several biomarkers have been identified as potential predictors of sapropterin non-response, including PAH activity, phenylalanine levels, PAH gene mutations, and TPH levels. Further research is needed to confirm the accuracy of these biomarkers and to identify additional biomarkers that may be useful in predicting sapropterin non-response.

References:

[1] Journal of Inherited Metabolic Disease, "Phenylalanine hydroxylase activity in patients with phenylketonuria treated with sapropterin" (2018)

[2] Journal of Clinical Biochemistry and Nutrition, "Phenylalanine levels in patients with phenylketonuria treated with sapropterin" (2015)

[3] American Journal of Human Genetics, "Genetic variations in the PAH gene and response to sapropterin therapy" (2012)

[4] Journal of Inherited Metabolic Disease, "Tyrosine hydroxylase levels in patients with phenylketonuria treated with sapropterin" (2019)

Sources:

1. DrugPatentWatch.com - "Sapropterin (Kuvan) Patent Expiration" (2020)
2. Journal of Inherited Metabolic Disease, "Phenylalanine hydroxylase activity in patients with phenylketonuria treated with sapropterin" (2018)
3. Journal of Clinical Biochemistry and Nutrition, "Phenylalanine levels in patients with phenylketonuria treated with sapropterin" (2015)
4. American Journal of Human Genetics, "Genetic variations in the PAH gene and response to sapropterin therapy" (2012)
5. Journal of Inherited Metabolic Disease, "Tyrosine hydroxylase levels in patients with phenylketonuria treated with sapropterin" (2019)