Ultragenyx Reports Positive Longer-term Data From Phase 1/2 Studies Of DTX401, DTX301

(RTTNews) - Biopharmaceutical company Ultragenyx Pharmaceutical Inc. (RARE) on Friday announced positive longer-term safety and efficacy data from the first three cohorts of the ongoing Phase 1/2 studies of DTX401, an investigational adeno-associated virus or AAV gene therapy for Glycogen Storage Disease Type Ia (GSDIa), and DTX301, an AAV gene therapy for ornithine transcarbamylase (OTC) deficiency.

GSDIa is the most severe genetically inherited glycogen storage disease. It is caused by a defective gene coding for the enzyme G6Pase-a, resulting in the inability to regulate blood sugar, or glucose.

OTC deficiency, the most common urea cycle disorder, is caused by a genetic defect in a liver enzyme responsible for detoxification of ammonia.

"GSDIa patients treated with DTX401 demonstrate continually improved glucose metabolism with reduction or elimination of cornstarch dependence over time. OTC patients treated with DTX301 show good metabolic control after tapering or discontinuation of alternate pathway medications and protein restricted diet," said Eric Crombez, Chief Medical Officer of the Ultragenyx Gene Therapy development unit.

Ultragenyx noted that dosing is nearing completion for the prophylactic steroid cohorts in both studies. The company is continuing discussions with regulatory agencies for both programs.

Ultragenyx expects to initiate Phase 3 studies for DTX401 in the first half of 2021 and for DTX301 in the second half of 2021.

The company submitted an Investigational New Drug or IND application in December as planned for UX701, an AAV gene therapy for Wilson disease. The company said it plans to start a seamless single-protocol Phase 1/2/3 study for UX701 in the first half of 2021.