Ultragenyx Pharmaceutical Inc. and Mereo BioPharma Group plc today announced promising 14-month results for osteogenesis imperfecta (OI) from the Phase 2 portion of the ongoing Phase 2/3 Orbit study (NCT05125809). The data demonstrated that treatment with setrusumab (UX143) significantly reduced fracture rates and improved bone mineral density (BMD) in patients with osteogenesis imperfecta.
As of the May 24, 2024 data cut-off, setrusumab treatment resulted in a substantial 67% reduction in the annualized fracture rate, with a persistent median annualized fracture rate of 0.00 (p=0.0014). Patients treated with setrusumab for at least 14 months showed sustained improvements in lumbar spine BMD, with a mean increase from baseline of 22% (p<0.0001) and a mean improvement in Z-score of +1.25 (p<0.0001).
“These results are consistent with our expectations, showing that setrusumab significantly reduces fractures and improves BMD in patients with osteogenesis imperfecta,” said Dr. Gary S. Gottesman, Professor of Pediatrics and Medicine at Washington University School of Medicine. “The ongoing response suggests that patients will continue to benefit from this treatment over the long term.”
DTX401 Gene Therapy Reduces Cornstarch Intake and Maintains Glucose Control in GSDIa Patients
The study also met key secondary endpoints, including a reduction in the number of daily cornstarch doses and maintenance of glucose control at Week 48. The mean reduction in cornstarch doses per day was 1.1 in the DTX401 group compared to 0.2 in the placebo group (p=0.0011). Patients in the DTX401 group also showed significant improvement in nighttime cornstarch dosing frequency and quantity compared to the placebo group.
“The meaningful reduction in cornstarch intake while maintaining glucose control indicates a significant improvement in patients’ quality of life,” stated Dr. Rebecca Riba-Wolman, director of the Glycogen Storage Disease Program at Connecticut Children’s Medical Center. “This treatment could alleviate daily concerns for people with GSDIa, reducing the risk of severe low blood sugar and acidosis.”
The study demonstrated an acceptable safety profile for DTX401, with manageable hepatic effects and no observed AAV8 class effects of dorsal root ganglion toxicity or thrombotic microangiopathy through Week 48. Full 48-week data will be presented at a scientific conference later this year to support a marketing application in 2025.
Ultragenyx Presents Promising Long-Term Data for Advances Setrusumab for Osteogenesis Imperfecta
Ultragenyx recently presented long-term Phase 1/2 data for DTX401 at the American Society of Gene and Cell Therapy 2024, showing durable response and sustained reductions in cornstarch intake lasting up to five years.
Ultragenyx is developing setrusumab for pediatric and young adult patients with osteogenesis imperfecta sub-types I, III, and IV through the Phase 2/3 Orbit study and Phase 3 Cosmic study. The Orbit study evaluates setrusumab’s effect on clinical fracture rate in patients aged 5 to 25 years, with the Phase 3 portion enrolling an additional 158 patients across 11 countries. The Cosmic study focuses on patients aged 2 to <7 years, comparing setrusumab with intravenous bisphosphonates.
Setrusumab is a fully human monoclonal antibody that inhibits sclerostin, a negative regulator of bone formation, aiming to increase bone mineral density and strength. Ultragenyx and Mereo BioPharma are collaborating on setrusumab’s development, focusing on pediatric and young adult patients with osteogenesis imperfecta.
Resource: Ultragenyx Pharmaceutical, June 11, 2024
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