Sangamo's Gene Therapy for Fabry Disease Clears FDA Hurdle: What This Means for Rare Disease Treatment

Sangamo Therapeutics has achieved a significant milestone in its pursuit of bringing a groundbreaking gene therapy to patients with Fabry disease. The FDA has greenlit the company’s rolling Biologics License Application (BLA) submission strategy for isaralgagene civaparvovec, marking an accelerated pathway toward potential approval.

Understanding the Disease and the Breakthrough

Fabry disease represents one of the most challenging lysosomal storage disorders, driven by mutations in the galactosidase alpha (GLA) gene. The condition triggers progressive deterioration across multiple organ systems—kidneys, heart, neurological tissue, vision, digestive tract, and skin—making it a devastating diagnosis for affected individuals. Current treatment options manage symptoms but do not fundamentally halt disease progression.

Isaralgagene civaparvovec offers a fundamentally different approach: a single-administration gene therapy designed to address the underlying genetic cause rather than merely treating symptoms.

Clinical Evidence Supporting FDA’s Decision

The Phase 1/2 STAAR study provided compelling evidence. Most notably, the therapy demonstrated a positive mean annualized estimated glomerular filtration rate (eGFR) slope at 52 weeks across all treated patients—a critical metric indicating preservation or improvement of kidney function. This endpoint will serve as the cornerstone for FDA approval decisions, representing a rare instance where regulators have aligned with the company’s chosen primary efficacy measure.

Beyond kidney outcomes, the study revealed multi-organ clinical benefits that exceed currently available therapeutic standards, suggesting isaralgagene civaparvovec could fundamentally reshape treatment paradigms for Fabry disease patients.

Regulatory Acceleration in Motion

The FDA’s acceptance of the rolling submission indicates confidence in the program’s trajectory. The gene therapy has already accumulated substantial regulatory recognition: Orphan Drug designation, Fast Track status, and RMAT (Regenerative Medicine Advanced Therapy) designation from the FDA, alongside Orphan Medicinal Product designation, PRIME eligibility from the European Medicines Agency, and Innovative Licensing and Access Pathway recognition from the U.K. Medicines and Healthcare products Regulatory Agency.

Next Steps and Timeline

Sangamo intends to initiate the rolling BLA submission to the FDA under the accelerated approval pathway during the fourth quarter of 2025. This phased review strategy allows regulators to evaluate data as it becomes available, potentially compressing the traditional approval timeline for this potentially transformative therapy.