A Study to Learn About the Safety and Effects of the Study Drug PRX-102 in Children and Adolescents With Fabry Disease

DRUG

PRX-102 1 mg/kg every two weeks

Drug: PRX-102 1 mg/kg every two weeks

Incidence of Treatment Emergent Adverse Events (TEAEs)

Time frame: 12 Months

Incidence of Infusion Related Reactions (IRRs)

Time frame: 12 Months

Incidence of Injection site reactions (ISRs)

Time frame: 12 Months

Change in Tanner stage

Time frame: Baseline and 12 Months

Tanner Staging of Sexual Development will be used to assess sexual development (i.e. breast development (B1 to B5) and pubic hair development (Ph-1 to Ph-5) in females and pubic hair and genetical development (G1-G5) in males.

Change from baseline of 12-lead ECG quantitative parameters: Mean Heart Rate

Time frame: Baseline and 12 Months

Change from baseline of 12-lead ECG quantitative parameters: PR Interval

Time frame: Baseline and 12 Months

Change from baseline of 12-lead ECG quantitative parameters: QRS Duration

Time frame: Baseline and 12 Months

Change from baseline of 12-lead ECG quantitative parameters: QT Interval

Time frame: Baseline and 12 Months

Change from baseline of 12-lead ECG quantitative parameters: QTc Interval

Time frame: Baseline and 12 Months

Change from baseline of 12-lead ECG quantitative parameters: ST Segment

Time frame: Baseline and 12 Months

Incidence of treatment-emergent Anti-Drug Antibodies (ADAs)

Time frame: Baseline and 12 Months

Incidence of premedication use at each visit and change of infusion premedications from baseline

Time frame: Baseline and 12 Months

Pharmacokinetics: Time to maximum plasma concentration (tmax)

Time frame: Stage I - Baseline, week 2, week 4, week 12, week 26 and week 52; Stage II -Baseline, week 12, week 26 and week 52]

Pharmacokinetic : Area under the plasma concentration-time curve from time 0 to time t (AUC0 t)

Time frame: Stage I - Baseline, week 2, week 4, week 12, week 26 and week 52; Stage II -Baseline, week 12, week 26 and week 52]

Pharmacokinetics: Area under the curve from time 0 to 2 weeks (AUC0-2wk)

Time frame: Stage I - Baseline, week 2, week 4, week 12, week 26 and week 52; Stage II -Baseline, week 12, week 26 and week 52]

Pharmacokinetics: Area under the curve from time 0 to infinity (AUC0-∞)

Time frame: Stage I - Baseline, week 2, week 4, week 12, week 26 and week 52; Stage II -Baseline, week 12, week 26 and week 52]

Pharmacokinetics: Terminal half-life (t1/2)

Time frame: Baseline, week 2, week 4, week 12, week 26 and week 52]

Pharmacokinetics: Area under the curve over a dosing interval (AUCτ)

Time frame: Baseline, week 2, week 4, week 12, week 26 and week 52; Stage II -Baseline, week 12, week 26 and week 52]

Pharmacokinetics: Observed drug concentration at the end of the dosing interval (Cτ)

Time frame: Stage I - Baseline, week 2, week 4, week 12, week 26 and week 52; Stage II -Baseline, week 12, week 26 and week 52]

Pharmacokinetics: Clearance (Cl)

Time frame: Stage I - Baseline, week 2, week 4, week 12, week 26 and week 52; Stage II -Baseline, week 12, week 26 and week 52]

Pharmacokinetics: Volume of distribution (Vz)

Time frame: Stage I - Baseline, week 2, week 4, week 12, week 26 and week 52; Stage II -Baseline, week 12, week 26 and week 52]

Change in eGFR

Time frame: Baseline and 12 Months

Change in annualized eGFR slope

Time frame: Baseline and 12 Months

Change in urine albumin levels

Time frame: Baseline and 12 Months

Change in urine protein levels

Time frame: Baseline and 12 Months

Change from baseline in LVMi as assessed by echocardiogram

Time frame: Baseline and 12 Months

Echocardiogram parameters include left ventricular mass index (LVMi)

Change from baseline in LVMi as assessed by echocardiogram

Time frame: Baseline and 12 Months

Echocardiogram parameters include ejection fraction

Change from baseline in LVMi as assessed by echocardiogram

Time frame: Baseline and 12 Months

Echocardiogram parameters include, fractional shortening

Change from baseline in LVMi as assessed by echocardiogram

Time frame: Baseline and 12 Months

Echocardiogram parameters include left ventricular mass

Change from baseline in LVMi as assessed by echocardiogram

Time frame: Baseline and 12 Months

Echocardiogram parameters include valve abnormalities and thickness.

Incidence of any cardiac arrythmias as assessed by Holter ECG

Time frame: Baseline and 12 Months

Change in plasma levels of cardiac biomarkers

Time frame: Baseline and 12 Months

High-sensitivity cardiac troponin T (hs-cTnT) and N- terminal pro brain natriuretic peptide (NT-Pro BNP) will be assessed.

Change in plasma level of Gb3 concentration (nM)

Time frame: Baseline and 12 Months

Change in plasma level of lyso-Gb3 (nM)

Time frame: Baseline and 12 Months

Change in urine level of lyso-Gb3 (nM)

Time frame: Baseline and 12 Months

Incidence of change from baseline in the number of different pain medications

Time frame: Baseline and 12 Months

Incidence of Fabry Clinical Events

Time frame: 12 Months

FCEs are classified into four categories: renal, cardiac, cerebrovascular and death due to non-cardiac reasons

Change from baseline of Mainz Severity Score Index (MSSI) scores

Time frame: Baseline and 12 Months

Domains (general, neurological, cardiovascular, renal dysfunction)

Change from baseline of PedsQL-GI (or GSRS for subjects who reaches 18 yrs of age) scores

Time frame: Baseline and 12 Months

Change from baseline of FPHPQ scores

Time frame: Baseline and 12 Months

Change from baseline of PedsQL-PPQ (or BPI-SF for subjects who reaches 18 yrs of age) scores

Time frame: Baseline and 12 Months

Change from baseline of EQ-5D-Y (or EQ-5D-5L for subjects who reaches 18 yrs of age) scores

Time frame: Baseline and 12 Months

What is a clinical trial?

A clinical trial is a research study that tests new medical treatments, drugs, devices, or procedures to determine their safety and effectiveness. Trials are carefully designed and monitored to protect participants while advancing medical knowledge.

Is it safe to participate?

Clinical trials follow strict safety guidelines and ethical standards. Trials must be reviewed and approved, and participants are closely monitored by medical professionals throughout the study. You can withdraw at any time if you choose.

Will I be compensated?

Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.

Will I receive a placebo instead of treatment?

When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.

Can I leave a trial if I change my mind?

Absolutely. Participation in clinical trials is completely voluntary. You have the right to withdraw from the study at any time, for any reason, without penalty or loss of benefits to which you are otherwise entitled.

How long does a clinical trial last?

Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.