A Study of the Safety, Efficacy and Pharmacokinetics of Glycerol Phenylbutyrate in Pediatric Subjects Under 2 Years of Age With Urea Cycle Disorders

The percentage of participants with successful transition is based on Investigator response to the question, "Has transition to 100% RAVICTI been successful with controlled ammonia?" For participants 2 months of age and older, after a minimum of 24 hours of ammonia monitoring following the first full dose of RAVICTI alone, the participant was effectively transitioned when following conditions were met: no signs and symptoms of hyperammonemia; ammonia level less than 100 μmol/L (without normalization of ammonia, ie, without conversion of values from local laboratories with varying normal ranges to standardized values); and eligible for discharge per Investigator judgment.

The percentage of participants with successful transition is based on Investigator response to the question, "Has transition to 100% RAVICTI been successful with controlled ammonia?" For participants < 2 months of age, after a minimum of 24 hours of ammonia monitoring following the first full dose of RAVICTI alone, the participant was effectively transitioned when following conditions were met: no signs and symptoms of hyperammonemia; ammonia level less than 100 μmol/L (without normalization of ammonia, ie, without conversion of values from local laboratories with varying normal ranges to standardized values); and eligible for discharge per Investigator judgment.

HAC is defined having signs and symptoms consistent with hyperammonemia (such as but not limited to frequent vomiting, nausea, headache, lethargy, irritability, combativeness, and/or somnolence) associated with high blood ammonia and requiring medical intervention. Rate of HACs per 6 months during the safety extension is calculated as sum of (number of HAC) / sum of (days during first 6 months starting on Day 8 or number days on RAVICTI, whichever is less) across all participants in the corresponding group.

An adverse event (AE) is any untoward medical occurrence, whether or not the event is considered related to the study drug. A serious AE is any AE that: results in death; is life threatening; requires hospitalization or prolongation of existing hospitalization; results in disability/incapacity; is a congenital anomaly/birth defect; is an important medical event. TEAEs are defined as AEs with an onset date on or after the first dose of study medication until study discontinuation. The Investigator assessed the causal relationship of each TEAE to the study drug as not related, possibly related, or probably related.

To assess any effect of study drug treatment on growth, Z-scores were calculated to express the deviation from a reference population for BMI. The Z-scores are based on the World Health Organization's Child Growth Standards charts. Negative Z-scores indicate lower than typical for age and gender while positive scores indicate higher than typical for age and gender.

To assess any effect of study drug treatment on growth, Z-scores were calculated to express the deviation from a reference population for BSA. The Z-scores are based on weight-for-length charts. Negative Z-scores indicate lower than typical for age and gender while positive scores indicate higher than typical for age and gender.

HAC is defined as having signs and symptoms consistent with hyperammonemia (such as but not limited to frequent vomiting, nausea, headache, lethargy, irritability, combativeness, and/or somnolence) associated with high blood ammonia and requiring medical intervention. Rate of HACs per 6 months during the safety extension was calculated as sum of (number of HAC) / sum of (days during first 6 months starting on Day 8 or number days on RAVICTI, whichever is less) across all participants in the corresponding group.

An AE is any untoward medical occurrence, whether or not the event is considered related to the study drug. A serious AE is any AE that: results in death; is life threatening; requires hospitalization or prolongation of existing hospitalization; results in disability/incapacity; is a congenital anomaly/birth defect; is an important medical event. TEAEs are defined as AEs with an onset date on or after the first dose of study medication until study discontinuation. The Investigator assessed the causal relationship of each TEAE to the study drug as not related, possibly related, or probably related.

To assess any effect of study drug treatment on growth, Z-scores were calculated to express the deviation from a reference population for BMI. The Z-scores are based on the World Health Organization's Child Growth Standards charts. Negative Z-scores indicate lower than typical for age and gender while positive scores indicate higher than typical for age and gender.

To assess any effect of study drug treatment on growth, Z-scores were calculated to express the deviation from a reference population for BSA. The Z-scores are based on weight-for-length charts. Negative Z-scores indicate lower than typical for age and gender while positive scores indicate higher than typical for age and gender.