Phase 2 N=33 Treatment

Dose-Ranging Study of ST-920, an AAV2/6 Human Alpha Galactosidase A Gene Therapy in Subjects With Fabry Disease (STAAR)

Fabry Disease

Bottom Line

View on ClinicalTrials.gov: NCT04046224 ↗

Enrolled (actual)

Serious AEs

12.1%

Results posted

Apr 2026

Primary outcome: Primary: Incidence of Treatment-emergent Adverse Events (TEAEs) - All — 2; 2; 3; 2 Participants

Study Design & Population

Study type: Interventional
Phase: Phase 2
Interventions: ST-920 (Biological)
Age: Adult, Older Adult · 18+ yrs
Sex: All
Sponsor: Sangamo Therapeutics
Primary completion: Apr 2025

Outcome Measures

Outcome	Result	p-value
PRIMARY Incidence of Treatment-emergent Adverse Events (TEAEs) - All	2; 2; 3; 2; 5; 5	—
PRIMARY Incidence of Treatment-emergent Adverse Events (TEAEs) - Related to ST-920	0; 0; 0; 0; 5; 4	—
PRIMARY Incidence of Treatment-emergent Adverse Events (TEAEs) - Serious	0; 0; 0; 0; 0; 0	—
PRIMARY Incidence of Treatment-emergent Adverse Events (TEAEs) - Any TEAEs Leading to Study Discontinuation or Withdrawal	0; 0; 0; 0; 0; 0	—
SECONDARY To Assess Alpha Gal-A Activity in Plasma Over Time	43.596; 38.549; 75.534; 60.062; 16.244; 24.098	—

Summary

This is the first in human treatment with ST-920, an adeno-associated virus (AAV2/6) vector encoding the complementary deoxyribonucleic acid (cDNA) for human a-Gal A. The purpose of this study is to evaluate the safety and tolerability of ascending doses of ST-920. ST-920 aims to provide stable, long-term production of α-Gal A at therapeutic levels in subjects with Fabry disease. The constant production of α-Gal A in humans should, importantly, enable reduction and potentially clearance of Fabry disease substrates Gb3 and lyso-Gb3. On Day 1, patients will be infused intravenously with a single dose of ST-920 and followed for a period of 52 weeks.

Eligibility Criteria

Inclusion Criteria

≥ 18 years of age
Documented diagnosis of Fabry disease
One or more of the following symptoms: i) cornea verticillata, ii) acroparesthesia, iii) anhidrosis, iv) angiokeratoma
Subject must be fully vaccinated (as per the Centers for Disease Control and Prevention (CDC) definition in the US and as per local guidelines in other countries) for Coronavirus Disease (COVID-19) at least one month prior to dosing

Additional Inclusion Criteria:

Renal Cohort:

Screening estimated glomerular filtration rate (eGFR) value between 40-90 mL/min/1.73 m²
Linear negative eGFR slope (estimated from at least 3 serum creatinine values within 18 months, including the value obtained during screening visit) of ≥ 2 mL/min/1.73m²/year

Cardiac Cohort:

Left ventricular hypertrophy (LVH) in 2D echocardiography or cardiac magnetic resonance imaging (CMR) defined as an end diastolic septum and posterior wall thickness ≥12 mm with no other explanation for LVH, OR presentation with cardiac changes indicative of disease progression such as decreased global longitudinal strain on 2D strain echocardiography or low native T1 mapping on CMR

Exclusion Criteria

Neutralizing antibodies to AAV6
eGFR 0.5 g/g who are not being treated with an ACE inhibitor or ARB

Cardiac cohort:

Significant cardiac fibrosis defined by late gadolinium enhancement on CMR
Any contraindications to CMR as per local hospital/institution guidelines
Angiotensin converting enzyme (ACE) inhibitor or angiotensin receptor blocker (ARB) therapy initiated within 4 weeks prior to screening or changed ACE inhibitor or ARB dose in the 4 weeks prior to screening
New York heart association (NYHA) Class IV

View full record on ClinicalTrials.gov →

Data sourced from ClinicalTrials.gov (NCT04046224). Outcome figures and adverse-event rates are extracted automatically from the registry's posted results and are provided for clinician reference, not as a substitute for the primary publication.