Ultragenyx Pharmaceutical Inc. (NASDAQ:RARE) on Wednesday announced the publication of 96-week Phase 3 trial data evaluating its gene therapy GENGLYCOS, also known as DTX401, for patients with glycogen storage disease type Ia (GSDIa).
Published in The Journal of Inherited Metabolic Disease, the long-term findings demonstrate sustained efficacy and safety for the newly approved therapy, which targets patients eight years of age and older.
Sustained Efficacy And Nighttime Relief
The study previously met its primary endpoint at Week 48 with a 41% mean reduction in cornstarch intake for DTX401 patients versus 10% for placebo.
By Week 96, both original participants and crossover subjects achieved a 61% mean reduction in daily cornstarch intake.
Additionally, 67% of initial participants and 72% of crossover participants achieved at least a 50% decrease in daily cornstarch reliance.
Treatment with DTX401 significantly reduced nighttime cornstarch burden, which accounted for roughly half of participants’ daily caloric intake at baseline.
By Week 96, two-thirds of all participants eliminated at least one overnight dose, while 33% of original patients and 42% of crossover patients completely stopped nighttime cornstarch use while maintaining stable glycemic control.
Patient Outcomes And Safety Profile
Patient-reported outcomes showed 83% of DTX401-dosed participants met or exceeded their baseline threshold for meaningful reduction by Week 48.
By Week 96, up to 95% reported overall condition improvement, allowing patients to transition toward balanced diets aligning with U.S. Dietary Guidelines.
DTX401 maintained a manageable safety profile through two years.
The most frequent treatment-related adverse events involved temporary liver enzyme spikes treated with prophylactic corticosteroids.
Researchers recorded no class-related toxicity, malignancy, or thrombotic microangiopathy.
RARE Stock Price Activity: Ultragenyx Pharmaceutical shares were down by 0.08% to $25.79 at the time of publication Wednesday, according to Benzinga Pro data.
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