BRISBANE, Calif. – Sangamo Therapeutics, Inc. (Nasdaq: SGMO), a genomic medicine company, today announced preliminary results from the Phase 1/2 STAAR clinical study evaluating isaralgagene civaparvovec, or ST-920, a wholly owned gene therapy product candidate for the treatment of Fabry disease. As of the September 17, 2021 cutoff date, results from the four patients treated in the first two dose cohorts (0.5e13 vg/kg and 1e13 vg/kg) showed that isaralgagene civaparvovec was generally well tolerated. All four patients exhibited above normal alpha-galactosidase A (α-Gal A) activity, which was maintained for up to one year for the first patient treated and through 14 weeks for the most recently treated patient. Activity of 2-fold to 15-fold above mean normal was observed at last measurement as of the cutoff date. Withdrawal from enzyme replacement therapy (ERT) has taken place for one patient and is planned for the other patient on ERT, based on the stability of their α-Gal A activity following treatment.
“There is significant unmet need in Fabry disease, a progressive and challenging condition that is currently treated with frequent burdensome infusions that do not adequately address the underlying disease,” said Rob Schott, M.D., M.P.H, F.A.C.C, Head of Development at Sangamo. “We are encouraged by these early yet promising results, particularly that the first three treated patients dosed all reported improvements in their ability to sweat, which is noteworthy as this limits a person’s capability to tolerate strenuous tasks and exercise. As we continue with this study, we hope to further understand the potential treatment effect over the longer-term and in more patients, while we initiate plans for a Phase 3 trial.”
A presentation containing additional details about the study and these results is available on the Events & Presentations page of Sangamo’s website.
As of the cutoff date, there were no treatment-related adverse events higher than Grade 1 (mild) and no treatment-related serious adverse events. No patients experienced liver enzyme elevations requiring steroid treatment.
The one patient with a significant elevation in plasma lyso-Gb3 pre-treatment showed significant reductions of approximately 40% (from baseline within 10 weeks after dosing, maintained through Week 32) in this biomarker after treatment with isaralgagene civaparvovec. Patients with low baseline levels of lyso-Gb3 maintained steady levels through the cutoff date.
The fifth patient in the Phase 1/2 STAAR study, who is the first patient in the third cohort (3e13vg/kg), was dosed after the cutoff date. The sixth patient is currently in screening, also for the third dose cohort. Sangamo expects to provide updated results from the STAAR study throughout 2022 and present these results at a medical meeting.
Based on STAAR study results to date, Sangamo has initiated planning for a Phase 3 clinical trial.
About the STAAR Study
The Phase 1/2 STAAR study is a global open-label, single-dose, dose-ranging, multicenter clinical study designed to evaluate the safety and tolerability of isaralgagene civaparvovec, or ST-920, a gene therapy product candidate in patients with Fabry disease. Isaralgagene civaparvovec requires a one-time infusion, without preconditioning. The STAAR study is enrolling patients who are on ERT, are ERT pseudo-naïve (defined as having been off ERT for six or more months), or who are ERT-naïve. The age range of the four patients dosed as of the cutoff date is 22 to 48 years old. The U.S. Food and Drug Administration has granted Orphan Drug designation to isaralgagene civaparvovec, which has also received Orphan Medicinal Product designation from the European Medicines Agency.
About Fabry Disease
Fabry disease is a lysosomal storage disorder caused by mutations in the galactosidase alpha gene (GLA), which leads to deficient alpha-galactosidase A (α-Gal A) enzyme activity, which is necessary for metabolizing globotriaosylceramide (Gb3). The buildup of Gb3 in the cells can cause serious damage to vital organs including the kidney, heart, nerves, eyes, gut and skin. Symptoms of Fabry disease can include decreased or absent sweat production, heat intolerance, angiokeratoma (skin blemishes), vision problems, kidney disease, heart failure, gastrointestinal disturbance, mood disorders, neuropathic pain and tingling in the extremities.
About Sangamo Therapeutics
Sangamo Therapeutics is a clinical-stage biopharmaceutical company with a robust genomic medicines pipeline. Using ground-breaking science, including our proprietary zinc finger genome engineering technology and manufacturing expertise, Sangamo aims to create new genomic medicines for patients suffering from diseases for which existing treatment options are inadequate or currently don’t exist. For more information about Sangamo, visit www.sangamo.com.