Ultragenyx announces program, updates on GTX-102, UX701, setrusumab

Ultragenyx Pharmaceutical will provide updates on its development pipeline, including setrusumab for osteogenesis imperfecta, GTX-102 for Angelman syndrome, UX701 in Wilson disease and the rest of the company’s gene therapy portfolio at an Analyst Day held in New York City and by webcast. Analyst Day Updates. “UX143 monoclonal antibody for Osteogenesis Imperfecta: Interim Phase 2 data from the Phase 2/3 Orbit study show statistically significant decrease in annualized fracture rates following at least 6 months of treatment.” Data presented at the American Society for Bone and Mineral Research 2023 Annual Meeting show that treatment with setrusumab reduced the annualized fracture rate by 67% and this reduction was associated with continuing large and meaningful improvements in bone mineral density. Setrusumab was generally well tolerated with no drug related serious adverse events reported and no reports of drug-related hypersensitivity. The company plans to provide updated Phase 2 data next year. “GTX-102 antisense oligonucleotide for Angelman syndrome: Data from the extension cohorts in the Phase 1/2 study show clinically meaningful improvements in multiple domains.” Quantitative data show improvements across multiple clinical domains compared to natural history data, where available, and clinical changes were associated with quantitative changes in EEG. Long term data showed patients who stopped and restarted treatment reacquired previously gained developmental skills when they were re-dosed with the current regimen. There have been no additional treatment-related SAEs, including lower extremity weakness, since November 2022. Data from the dose expansion cohorts on at least 20 patients who have been on therapy for at least 6 months is anticipated in the first half of 2024. “UX701 AAV gene therapy for Wilson disease: Four of five patients in the lowest-dose cohort of the Phase 1/2/3 Cypress 2+ study show improvements in tapering standard of care”: Four out of 5 patients in the low-dose Cohort 1 have had reductions in urinary copper and are tapering off of chelators and/or zinc therapy, including 2 of 3 earlier treated patients in the Cohort that are now completely off standard therapy. UX701 has been generally well tolerated with no treatment-related SAEs. The seamless study is expected to complete dosing of all 3 dose cohorts in Stage 1 at the end of 2023 and these data are expected in the first half of 2024. Company also provided update on other late-stage gene therapy candidates: DTX401 AAV gene therapy for Glycogen Storage Disease Type Ia: The Phase 3 GlucoGene study was fully enrolled in the first quarter of 2023 and the company plans to provide preliminary data in the first half of 2024. UX111 for Sanfilippo syndrome: The pivotal Transpher A study has been fully enrolled and the company plans to meet with the FDA in the fourth quarter of 2023. DTX301 AAV gene therapy for Ornithine Transcarbamylase Deficiency: The Phase 3 Enh3ance study is expected to complete enrollment in the first half of 2024.