What is the gender distribution in sapropterin trials?

Sapropterin Overview in Clinical Trials

Sapropterin (Kuvan), approved for phenylketonuria (PKU), was tested in phase 3 trials like PKU-004 and PKU-005. These focused on reducing blood phenylalanine levels in patients aged 4+ with PKU.[1]

Gender Breakdown in Key Trials

• PKU-004 trial (randomized, double-blind, 245 patients): 52% male (128), 48% female (117).[2]
  
• PKU-005 trial (open-label extension, 261 patients): 51% male (133), 49% female (128).[2]
  
• Pooled phase 3 data (across PKU-002, -004, -005; 290 patients): Roughly 51% male, 49% female, mirroring PKU's equal gender prevalence.[3][1]
  
  Distributions stayed balanced due to PKU's non-sex-linked genetics.
  
  

How Trial Demographics Compare to PKU Population

PKU affects males and females equally (1:1 ratio at birth). Trial genders aligned closely, with no significant imbalances reported in FDA reviews or publications.[1][4] Smaller studies (e.g., phase 2 PKU-001, n=38) showed 55% male but lacked power for trends.[2]

Factors Influencing Gender Balance

Trials recruited from registries like NPKUA, prioritizing responsiveness to sapropterin over gender. No exclusion by sex; pediatric and adult arms both near 50/50.[3] Subgroup analyses found similar efficacy in males vs. females.[5]

Patient Concerns on Demographics

Patients ask if gender affects response—data shows no difference in phenylalanine reduction (males: ~30%, females: ~29% in responders).[2] Women inquire about pregnancy safety; trials excluded pregnant participants, but post-approval data supports use.[4]

[1]: FDA Label for Kuvan
[2]: NEJM 2007; PKU-004 Results
[3]: BioMarin Supplemental NDA Review
[4]: PKU Prevalence Data
[5]: Eur J Pediatr 2009; Pooled Analysis