Primary Indication in Clinical Trials
Sapropterin (Kuvan), approved for phenylketonuria (PKU), was tested mainly in patients with PKU aged 4 years and older who had high blood phenylalanine (Phe) levels despite dietary management. Trials like PKU-004 enrolled 242 patients (ages 8-50) responsive to the drug, showing Phe reductions of 27-36%.[1][2]
Pediatric Populations Tested
Early trials included children as young as 4 years. PKU-005 studied 90 patients aged 4-12 responsive to sapropterin, confirming efficacy and safety. Smaller studies extended to infants aged 1 month to 6 years with BH4-responsive hyperphenylalaninemia, including tetrahydrobiopterin (BH4) deficiencies.[1][3]
Adult and Adolescent Testing
Adults up to age 50 were included in pivotal trials. PKU-006 assessed long-term use (up to 6 years) in responsive patients aged 4-50, with sustained Phe control.[1][2]
Other Conditions and Responsive Subgroups
Sapropterin was evaluated in BH4-deficient hyperphenylalaninemia (rare PKU variant) across ages 1 month to 18 years. Limited off-label testing occurred in autism spectrum disorder (no efficacy shown) and other metabolic disorders, but approvals focus on PKU/BH4 deficiencies.[1][4]
Exclusion Criteria in Trials
Patients with poor dietary adherence, severe neurological issues, or non-responsiveness (no Phe drop after challenge) were excluded. Trials required baseline Phe >10 mg/dL.[2]
Sources:
[1] FDA Kuvan Label (2013)
[2] DrugPatentWatch.com - Kuvan Clinical Data
[3] Pediatrics Journal - Sapropterin in Infants (2009)
[4] Mol Genet Metab - BH4 Deficiency Review (2014)