NEW YORK – Sangamo Therapeutics on Monday said it is preparing to start a potential Phase III trial of its Fabry disease gene therapy ST-920 (isaralgagene civaparvovec) and plans to meet with the US Food and Drug Administration this summer to discuss the design of the trial.
The Brisbane, California-based genomic medicines company is advancing plans for ST-920 after it received fast-track designation from the US Food and Drug Administration. Fast-track designation gives Sangamo the opportunity to meet with the FDA more often to discuss the development program for ST-920 and allows the firm to apply for priority review or accelerated approval in the future.
Fabry disease, a rare lysosomal storage disorder, is caused by GLA gene mutations that result in deficiencies in the human alpha-galactosidase A (α-Gal A) enzyme needed to metabolize globotriaosylceramide. When globotriaosylceramide builds up in the body, it can damage vital organs and make patients intolerant to heat, and prone to skin damage, heart failure, vision problems, and other problems.
ST-920 is a liver-tropic recombinant adeno-associated virus 2/6 vector carrying the cDNA for the α-Gal A enzyme. The FDA previously granted ST-920 orphan drug designation.
Sangamo is currently studying ST-920 in the Phase I/II STAAR study, in which 20 patients have received a one-time infusion of the gene therapy without preconditioning. According to a data readout in February with 13 patients dosed, 78 percent had globotriaosylceramide (Gb3) substrate clearance six months after treatment and 77 percent had reduced urine podocyte loss in one of the first kidney biopsies. Patients also experienced clinically meaningful and statistically significant increases in mean general health scores.
Based on the data from the Phase I/II trial, Sangamo is now planning a Phase III study for ST-920, which it hopes to start by year-end based on its interactions with the FDA.