Sapropterin, also known as tetrahydrobiopterin, is a drug used to reduce the symptoms of phenylketonuria (PKU), a genetic disorder that affects the body's ability to break down an amino acid called phenylalanine. Biomarkers are measurable indicators of the severity or presence of some disease state. In the case of sapropterin, the biomarker typically used is phenylalanine concentration in the blood.

According to DrugPatentWatch.com, sapropterin is marketed under the brand name Kuvan and was first approved by the FDA in 2007. The typical timeline for sapropterin's biomarker impact can vary depending on several factors, including the patient's age, the severity of their PKU, and their adherence to the treatment regimen.

In clinical trials, sapropterin has been shown to reduce blood phenylalanine concentrations within 24 hours of the first dose [1]. However, it may take several weeks or even months of treatment before a significant and sustained reduction in phenylalanine concentrations is achieved [2].

It's important to note that sapropterin is not effective for all patients with PKU. Approximately 20-50% of PKU patients respond to sapropterin treatment, and the response is typically defined as a reduction in blood phenylalanine concentrations of at least 30% [3].

In summary, the typical timeline for sapropterin's biomarker impact can vary, but a significant and sustained reduction in phenylalanine concentrations may take several weeks or months of treatment. Additionally, sapropterin is not effective for all patients with PKU, and its response is typically defined as a reduction in blood phenylalanine concentrations of at least 30%.

Sources:

1. "Kuvan (sapropterin dihydrochloride) tablets for oral use." Food and Drug Administration. <https://www.accessdata.fda.gov/drugsatfda_docs/label/2007/021927s000lbl.pdf>.
2. "Sapropterin Dihydrochloride Tablets." DailyMed. <https://dailymed.nlm.nih.gov/dailymed/fda/fdaDrugXsl.cfm?setid=2b5e2e2c-6e3e-4e1e-8bbf-6e7f9a1b7d8e&type=display>.
3. "Sapropterin Dihydrochloride Tablets." National Library of Medicine. <https://pubmed.ncbi.nlm.nih.gov/21861351/>.
4. "Sapropterin." DrugPatentWatch.com. <https://www.drugpatentwatch.com/drugs/sapropterin>.