A Phase 3 Open-Label Study of Safety, Pharmacokinetics, and Activity of Weekly Subcutaneous Pegzilarginase in Subjects <24 Months Old With Arginase 1 Deficiency
This is an open-label, multicentre study to evaluate the safety, PK, and activity (PD) of weekly subcutaneous (SC) administration of pegzilarginase in subjects with ARG1-D who are \< 24 months of age. The study consists of a screening period of up to 4 weeks, a subsequent 12-week treatment period, and a safety follow-up period of 8 weeks.
• Subjects must be \< 24 months of age on the date of informed consent
• Confirmed diagnosis of ARG1-D documented in medical records by at least 1 of the following methods:
‣ elevated plasma arginine levels
⁃ a mutation analysis revealing a pathogenic variant
⁃ red blood cell (RBC) arginase activity
• Subjects must weigh \> 8 kg due to clinical trial related blood collection volumes required
• Written informed consent by parent/legal guardian, in accordance with national stipulations, which includes compliance with the requirements and restrictions listed in the informed consent form and in this protocol
• At least one value of plasma arginine ≥ 180 μM during screening
• Documented confirmation from the Investigator and/or dietitian that the subject can:
‣ attempt to maintain a stable, age-appropriate level of protein consumption, including natural protein, and EAA supplementation within approximately ± 15% of dietitian recommended diet
⁃ attempt to maintain current use of ammonia scavengers, if prescribed