Percent predicted Hb and Altitude-adjusted DLco was calculated as: 100\*Adjusted DLco/Predicted DLco in unit of mL CO/min/mmHg where, adjusted DLco = Observed DLco (in mL CO/min/mmHg) times Hemoglobin-adjusted factor times Altitude-adjustment factor.

Percent predicted Hb and Altitude-adjusted DLco was calculated as: 100\*Adjusted DLco/Predicted DLco in unit of mL CO/min/mmHg where, adjusted DLco = Observed DLco (in mL CO/min/mmHg) times Hemoglobin-adjusted factor times Altitude-adjustment factor.

Spleen volume was assessed by abdominal magnetic resonance imaging (MRI) to quantitate the degree of splenomegaly in multiples of normal (MN).

Spleen volume was assessed by abdominal MRI to quantitate the degree of splenomegaly in MN.

The SRS rates 5 items: abdominal pain, abdominal discomfort, early satiety, dissatisfaction with abdominal body image, and difficulty to bend down using a numerical rating scale of 0 (absent) to 10 (worst imaginable). The total score of SRS ranges from 0 to 50, with higher scores (50) indicated worst imaginable rating. It was pre-specified as secondary endpoint for countries outside of US.

The SRS rates 5 items: abdominal pain, abdominal discomfort, early satiety, dissatisfaction with abdominal body image, and difficulty to bend down using a numerical rating scale of 0 (absent) to 10 (worst imaginable). The total score of SRS ranges from 0 to 50, with higher scores (50) indicated worst imaginable rating. It was pre-specified as secondary endpoint for countries outside of US.

TEAEs were defined as adverse events (AEs) that occurred or worsened during the on-treatment period (time from the start of investigational medicinal product \[IMP\]) administration until end of study (i.e. up to 64 weeks).

IARs were defined as AEs that occurred during the infusion or within up to 24 hours after the start of infusion and were considered as related or possibly related to the study treatment by the investigator or the sponsor. Protocol-defined IAR: all AEs that were identified as an IAR by the investigator. Events occurring greater than or equal to (\>=) 24 hours after the start of an infusion might had been judged an IAR at the discretion of the investigator or sponsor.

Change from Normal assessment (at Baseline) to Abnormal assessment (at Week 52) was reported. Physical examinations included following observations/measurements: examination of the skin, head, eyes, ears, nose, and throat; lymph nodes; heart, lungs, and abdomen; extremities and joints. Abnormality in physical examinations was based on investigator's discretion.

Change from Normal assessment (at Baseline) to Abnormal assessment (at Week 52) was reported. Neurological examination included: coordination examination, cranial nerve examination, extrapyramidal features, fundoscopy, gait and coordination examination, motor examination, tone peripheral nervous system, reflexes examination, sensory examination, strength examination, mental status.

Abnormal values in alanine aminotransferase (ALT), aspartate aminotransferase (AST), total bilirubin, and alkaline phosphatase were reported.

* Heart Rate (HR) High: \>=120 beats per minute (bpm) (adolescents), \>=120 bpm (children), \>=140 bpm (early children), \>=175 bpm (infants) \& increase from baseline (IFB) \>=20 bpm for all age categories. * HR Low: \<=50 bpm (adolescents), \<=50 bpm (children), \<=75 bpm (early children), \<=80 bpm (infants) \& decrease from baseline (DFB) \>=20 bpm for all age categories. * Systolic BP (SBP) High: \>=119 mmHg (adolescents), 108 mmHg (children), 101 mmHg (in early children), 98 mmHg (infants) \& IFB \>=20 mmHg for all age categories. * SBP Low: \<=90 mmHg (adolescents), \<= 80mm Hg (children), \<=70 mmHg (early children), \<=70 mmHg (infants) \& DFB \>=20 mmHg for all age categories. * Diastolic BP (DBP) High:\>=78 mmHg (adolescents), \>=72 mmHg (children), \>=59 mmHg (in early children), \>=54 mmHg (infants) \& IFB \>=10 mmHg for all age categories. * DBP Low:\<=54 mmHg (adolescents), \<=48 mmHg (children), \<=34 mmHg (early children), \<=34 mmHg (infants) \& DFB \>=10 mmHg for all age categories.

Criteria for potentially clinically significant ECG abnormalities: * High PR Interval: \>=180 milliseconds (ms) in adolescents, 170 ms in children, 160 ms in early children, and 140 ms in infants; * High QRS Interval: \>=110 ms in adolescents, 100 ms in children, 95 ms in early children and 85 ms in infants; * Prolonged QTc Fridericia (QTc F): \>450 ms in male adolescents, children, early children and infants or 470 ms in female adolescents, * QTc F \>500 ms; * QTc F increase from baseline \>60 ms.

Serum samples for immunogenicity assessment were analyzed to detect ADA. ADA response were categorized as: treatment emergent antibody i.e. treatment-induced/treatment-boosted response. A participant whose ADA status was positive anytime post-baseline and was negative or missing at baseline was considered to have treatment induced ADA. A participant whose ADA status was positive at baseline (pre-existing ADA) and the ADA titer level anytime post-baseline was significantly higher than that at baseline is considered to have treatment boosted ADA. Positive samples in the ADA assay were further analyzed in the NAb assay as positive NAb inhibition of catalytic activity and positive NAb inhibition of cellular uptake.

Evidence of portal hypertension was assessed by portal vein direction from liver ultrasound doppler.