A Study of Lumasiran in Infants and Young Children With Primary Hyperoxaluria Type 1

Percent change in spot urinary oxalate:creatinine ratio was estimated by an average percent change from baseline across Months 3 through 6. A negative change from Baseline indicates a favorable outcome.

A negative change from baseline indicates a favorable outcome.

Percentage of time that spot urinary oxalate: creatinine (UOx:Cr) ratio level is at or below ≤ 1.5xULN is calculated as (cumulative months at or below near normalization threshold divided by cumulative months of assessments)*100. Cumulative months in near-normalization is defined as the summation across all intervals that met the near-normal threshold and cumulative months of valid assessments is defined as the summation across all valid post-baseline collections. ULN levels of spot urinary oxalate to creatinine ratio where urine oxalate levels were analyzed using enzymatic assay. The age-dependent reference ULN levels of spot urinary oxalate to creatinine ratio are as follows: 1-1.5 years=0.158; 1.5-2 years=0.138; 2-2.5 years=0.124; 2.5-3 years=0.116; 3-3.5 years=0.102; 3.5-4 years=0.094; 4-4.5 years=0.088; 4.5-5 years=0.082; 5-5.5 years=0.077; 5.5-6 years=0.073.

The absolute change is represented as ratio of millimoles of urinary oxalate to millimoles of urinary creatinine.

The percentage of participants meeting the criteria (UOx:Cr ratio ≤ the ULN for age) at least at one post-baseline visit were reported for this outcome measure. The age-dependent reference ULN levels of spot urinary oxalate to creatinine ratio are as follows: 1-1.5 years=0.158; 1.5-2 years=0.138; 2-2.5 years=0.124; 2.5-3 years=0.116; 3-3.5 years=0.102; 3.5-4 years=0.094; 4-4.5 years=0.088; 4.5-5 years=0.082; 5-5.5 years=0.077; 5.5-6 years=0.073.

The percentage of participants meeting the criteria (UOx:Cr ratio ≤ 1.5xULN for age) at least at one post-baseline visit were reported for this outcome measure. The age-dependent reference ULN levels of spot urinary oxalate to creatinine ratio are as follows: 1-1.5 years=0.158; 1.5-2 years=0.138; 2-2.5 years=0.124; 2.5-3 years=0.116; 3-3.5 years=0.102; 3.5-4 years=0.094; 4-4.5 years=0.088; 4.5-5 years=0.082; 5-5.5 years=0.077; 5.5-6 years=0.073.

The lower limit of quantification (LLOQ) was 5.55 micromoles per liter (μmol/L). A negative change from baseline indicates a favorable outcome.

The LLOQ was 5.55 μmol/L. A negative change from Baseline indicates a favorable outcome.

Cmax was the maximum plasma concentration post-dose within the pharmacokinetic (PK) sampling time frame. Higher Cmax generally indicates higher drug exposure.

Tmax was estimated by calculating the time required to reach the maximum plasma concentration (Cmax) after the drug administration. Lower Tmax generally indicates faster drug absorption from the administration site.

Elimination half-life was estimated from the terminal phase of the plasma concentration-time profile post-dose. Shorter half-life generally indicates rapid drug elimination from the body.

AUC0-24 was the total drug exposure calculated as the area under the plasma concentration-time curve from the time of dosing (t = 0) to 24 hours.

AUC0-last was the total drug exposure calculated as the area under the plasma concentration-time curve from time 0 to the time of the last measurable (quantifiable) concentration (C_last).

AUC0-infinity was the total drug exposure estimated as the area under the plasma concentration-time curve from time 0 extrapolated to infinity.

Apparent clearance was calculated by dividing the area under the plasma concentration-time curve from zero infinity by the dose administered. A higher clearance generally indicates faster elimination from the body.

Apparent Volume of Distribution generally indicates the extent of drug distribution in the body.

eGFR [in milliliters per minute per 1.73 meters square (mL/min/1.73m^2)] was calculated from serum creatinine (SCr) based on the Schwartz Bedside Formula for participants ≥12 months of age at the time of assessment.

An Adverse Event (AE) is any untoward medical occurrence in a participant or clinical investigational participant administered a medicinal product and which does not necessarily have a causal relationship with this treatment.