Sangamo Therapeutics Reports Phase 1/2 STAAR Study Data on Fabry Disease Showing Sustained Benefits and Safety

Sangamo Therapeutics, a genomic medicine company based in Richmond, California, has shared promising updates from its Phase 1/2 STAAR study on isaralgagene civaparvovec, branded as ST-920. This gene therapy product candidate is being developed as a treatment for Fabry disease, offering hope as a durable, one-time therapy to significantly improve patient outcomes.

The latest data from the STAAR study supports the potential effectiveness of isaralgagene civaparvovec. The findings, which will be presented at the 21st Annual WORLDSymposium in San Diego, demonstrate sustained benefits with increased alpha-galactosidase A (α-Gal A) activity for nearly four years in the longest treated patient. This sustained enzyme activity is crucial for addressing the enzyme deficiency characteristic of Fabry disease.

A key highlight from the study is the positive mean estimated glomerular filtration rate (eGFR) slope observed among the 23 patients who had at least one year of follow-up. This result indicates substantial improvements in kidney function, a critical factor for those affected by Fabry disease. The significance of these improvements cannot be overstated, as kidney dysfunction is a leading cause of morbidity and mortality in this condition.

Safety data from the study shows that isaralgagene civaparvovec is generally well-tolerated, with most adverse events being mild to moderate. Importantly, there were no elevations in liver function tests post-dosing that required steroid intervention, and no severe adverse events led to study discontinuation. The efficacy of the treatment is further underscored by the fact that all 18 patients who started the study on enzyme replacement therapy (ERT) have been successfully withdrawn from ERT and remain off it.

On the regulatory front, Sangamo is preparing for potential accelerated approval. The data collected thus far is expected to support an Accelerated Approval pathway, with the company anticipating a Biologics License Application (BLA) submission to the U.S. Food and Drug Administration (FDA) in the latter half of 2025. The FDA has already shown alignment with this pathway, utilizing data from the ongoing STAAR study as a primary basis for approval under its Accelerated Approval Program.

Sangamo is also actively pursuing business development opportunities for a potential collaboration around ST-920. The continued success of the STAAR study not only highlights the potential of isaralgagene civaparvovec but also strengthens Sangamo's position in ongoing discussions with both the FDA and the European Medicines Agency.

The Phase 1/2 STAAR study is designed as a global open-label, single-dose, dose-ranging, multicenter clinical trial aimed at evaluating the efficacy and safety of isaralgagene civaparvovec in patients with Fabry disease. This study includes patients on ERT, those pseudo-naïve to ERT, and those who are ERT-naïve. The gene therapy involves a one-time infusion and has been granted various designations by regulatory bodies, including Orphan Drug and Fast Track designations by the FDA, as well as PRIME eligibility from the European Medicines Agency.

Fabry disease, a lysosomal storage disorder, results from mutations in the GLA gene, leading to deficient enzyme activity necessary for breaking down globotriaosylceramide (Gb3). Accumulation of Gb3 can severely impact vital organs, causing symptoms like kidney disease, heart problems, and neuropathic pain. Sangamo's promising results in addressing this enzyme deficiency offer a potential breakthrough for patients suffering from this debilitating disease.

In conclusion, Sangamo Therapeutics is making significant strides with its gene therapy candidate, ST-920, potentially setting a new standard in the treatment of Fabry disease. With encouraging data supporting both safety and efficacy, and a clear regulatory path ahead, this therapy could become a pivotal option for improving the lives of those affected by Fabry disease.