The FDA has granted accelerated approval to Genglycos (pariglasgene brecaparvovec-opnr, formerly DTX401), from Ultragenyx — the first therapy to target the root cause of glycogen storage disease type Ia (GSDIa), a rare inherited metabolic disorder.
In GSDIa, an enzyme deficiency prevents the liver from releasing glucose, so patients face constant risk of dangerously low blood sugar. Management is grueling: continuous monitoring and frequent doses of raw cornstarch, day and night, to keep glucose stable. Genglycos is a gene therapy that uses an AAV8 viral vector to deliver a functional gene to liver cells, addressing the underlying defect rather than just its symptoms.
The evidence
Approval rests on a 48-week Phase 3 trial (GlucoGene) in 46 participants, which showed a statistically significant reduction in the amount of cornstarch patients needed. The therapy is approved for adults and children aged 8 and older. “The approval of Genglycos fulfills our commitment to provide the first therapy that directly targets the root cause of GSDIa,” said Ultragenyx chief medical officer Dr. Eric Crombez.
What accelerated approval means
Accelerated approval lets a therapy reach patients based on a measure reasonably likely to predict benefit, with confirmation to follow. Ultragenyx will track two years of safety and efficacy data from a commercial group of about 50 patients plus 20 controls, monitored for up to a decade — standard practice for a one-time gene therapy in an ultra-rare disease.