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DTX401 · 2 trials · 2 indications
An AE is defined as any untoward medical occurrence, regardless of its causal relationship to study product. An SAE is defined as any event that: results in death; is immediately life threatening; requires inpatient hospitalization or prolongation of existing hospitalization; results in persistent or significant disability/incapacity; results in a congenital anomaly/birth defect; or an important medical event, in the opinion of the investigator. The relationship to study drug was categorized as unrelated, possible, probable or definite. A DLT is defined as any AE/SAE ≥ Grade 3 that is considered by the Investigator and/or Sponsor to be related to DTX401, based on the Nation Cancer Institute Common Terminology Criteria for Adverse Events (NCI CTCAE) Version 5.0 or later version. Per protocol, SAEs that occurred \> 30 days after EOS or Early withdrawal visit, did not need to be reported unless Investigator considered them related to study product.
| Arm | Type | Description |
|---|---|---|
| DTX401, Then Placebo | EXPERIMENTAL | Participants receive single peripheral intravenous (IV) infusion of DTX401 in solution. At week 48 participants receive single peripheral IV infusion of Placebo. |
| Placebo, Then DTX401 | PLACEBO_COMPARATOR | Participants receive single peripheral IV infusion of Placebo. At week 48 eligible participants receive single peripheral IV infusion of DTX401 solution. |
| DTX401 (Japan Only) | EXPERIMENTAL | Participants receive single peripheral intravenous (IV)infusion of DTX401 in solution. |
| DTX401 Cohort 1 | EXPERIMENTAL | Dose 1 (2.0 × 10\^12 GC/kg) with a reactive steroid regimen (6 weeks, at a starting dose of 40 mg/day, after alanine aminotransferase \[ALT\] elevation) |
| DTX401 Cohort 2 | EXPERIMENTAL | Dose 2 (6.0 × 10\^12 GC/kg) with a reactive steroid regimen (6 weeks, at a starting dose of 40 mg/day, after ALT elevation) |
| DTX401 Cohort 3 | EXPERIMENTAL | Dose 2 (6.0 × 10\^12 GC/kg) with an optimized reactive steroid regimen (7 weeks, at a starting dose of 60 mg/day, after ALT elevation) |
| DTX401 Cohort 4 | EXPERIMENTAL | Dose 2 (6.0 × 10\^12 GC/kg) with a prophylactic steroid regimen (8 weeks, at a starting dose of 60 mg/day, starting on Day 1) |
| Name | Type | Description |
|---|---|---|
| DTX401 | GENETIC | nonreplicating, recombinant, adeno-associated virus (AAV) serotype 8 (AAV8) |
| Placebo | OTHER | Normal Saline infusion |
| Oral prednisolone | DRUG | Participants who receive DTX401 solution will receive oral prednisolone |
| Placebo for oral prednisolone | DRUG | Participants who receive placebo will receive placebo oral prednisolone to maintain the study blind |
| steroid regimen | DRUG | prednisone or prednisolone to manage alanine aminotransferase (ALT) elevation |
Key Inclusion Criteria: * Documented GSDIa with confirmation by molecular testing or enzymatic activity on liver biopsy * Currently receiving a therapeutic regimen of cornstarch (or equivalent), following international guidance/recommendations with stable nutrition, glycemic, and clinical status. *...
DTX401 is an investigational gene therapy being developed for the treatment of Glycogen Storage Disease Type IA (GSDIa), a rare inherited metabolic disorder. It is designed to deliver a functional copy of the glucose-6-phosphatase gene to address the underlying enzyme deficiency. DTX401 is currently in clinical development and has not been approved by regulatory authorities.
DTX401 is a gene therapy that targets the underlying genetic cause of Glycogen Storage Disease Type IA by delivering a functional copy of the glucose-6-phosphatase gene. This enzyme is deficient in patients with GSDIa, leading to impaired glucose metabolism. The therapy uses an adeno-associated virus serotype 8 (AAV8) vector to deliver the gene.
DTX401 is being developed by Ultragenyx Pharmaceutical Inc., a biopharmaceutical company focused on rare diseases. Ultragenyx is publicly traded on the NASDAQ under the ticker symbol RARE. The company is conducting clinical trials to evaluate the safety and efficacy of DTX401 in patients with Glycogen Storage Disease Type IA.
DTX401 has completed a Phase 1 trial and a Phase 3 trial, both of which are listed as completed in clinical trial registries. The Phase 1 study evaluated safety and dose-finding in adults, while the Phase 3 study assessed gene transfer in a broader patient population. DTX401 remains investigational and is not yet approved.
DTX401 has been studied in two clinical trials. The first, NCT03517085, was a Phase 1 safety and dose-finding study in adults with GSDIa, completed with 12 participants. The second, NCT05139316, was a Phase 3 study of AAV8-mediated gene transfer in patients with GSDIa, completed with 49 participants across multiple countries.
DTX401 is also known as AAV8G6PC, as referenced in the title of its Phase 1 clinical trial. The name reflects the therapy's composition: an adeno-associated virus serotype 8 (AAV8) vector carrying the glucose-6-phosphatase (G6PC) gene. Both names refer to the same investigational gene therapy for Glycogen Storage Disease Type IA.