Sustained Benefits and Safety Profile in Sangamo's Phase 1/2 Fabry Disease Study

Sangamo Therapeutics, a genomic medicine company, has reported promising results from its Phase 1/2 STAAR clinical study of isaralgagene civaparvovec, a gene therapy for Fabry disease. The study has shown that the treatment can sustain elevated levels of alpha-galactosidase A (α-Gal A) for up to three years in some patients and all patients who discontinued enzyme replacement therapy (ERT) maintained this elevated activity for up to 19 months. The therapy also significantly reduced total antibody and neutralizing antibody titers against α-Gal A in patients with pre-existing antibodies from ERT.

The 13 patients monitored for over a year post-treatment exhibited stable kidney function and marked improvements in disease severity, quality of life, and gastrointestinal symptoms. The treatment demonstrated a favorable safety profile, with no liver function test elevations post-treatment requiring steroids. Sangamo has dosed four additional patients since the data cutoff date, completing the enrollment for the Phase 1/2 STAAR study. The company is in discussions with the U.S. FDA and other health authorities regarding the pathway to registration.

The preliminary data will be presented at the 20th Annual WORLDSymposium in San Diego, CA, and is also available on Sangamo’s website. Dr. Robert Hopkin, an investigator of the study, highlighted the potential of ST-920 as a single-dose treatment for Fabry disease, given its well-tolerated nature and sustained supraphysiologic α-Gal A activity. Lisa Rojkjaer, Sangamo's Chief Medical Officer, expressed optimism about the emerging data and the convenience of a single-dose treatment option.

The STAAR study is an open-label, single-dose, dose-ranging, multicenter clinical trial designed to assess the safety and tolerability of isaralgagene civaparvovec in Fabry disease patients. The study has enrolled patients on ERT, ERT pseudo-naïve, or ERT-naïve. The treatment has received Orphan Drug, Fast Track, and RMAT designations from the U.S. Food and Drug Administration, as well as Orphan Medicinal Product designation from the European Medicines Agency.

Fabry disease is a lysosomal storage disorder caused by a deficiency in α-Gal A enzyme activity, resulting from mutations in the GLA gene. This deficiency leads to a buildup of Gb3 in cells, causing damage to vital organs and a range of symptoms. Sangamo Therapeutics is focused on developing genomic medicine to treat serious neurological disorders and is exploring delivery beyond currently available methods.

The company is deferring further investments in planning for a registrational trial until securing a collaboration partnership or financing. Sangamo will also present pharmacology and safety data from nonclinical work for isaralgagene civaparvovec at the WorldSymposium, showcasing the potential for Phase 3 clinical dosing. A detailed report on the updated preliminary results from the Phase 1/2 STAAR study will be filed by Sangamo.