Ultragenyx Advances Multiple Gene Therapies Toward Regulatory Approval with DTX401 BLA Submission
Key Insights
Ultragenyx completed a rolling BLA submission for DTX401 gene therapy in Q4 2025, targeting Glycogen Storage Disease Type Ia (search) with Phase 3 data showing 61% reduction in daily cornstarch intake at Week 96.
The company's Phase 3 UX143 trials for osteogenesis imperfecta (search) are progressing toward final analyses with data expected by end of 2025, while GTX-102 for Angelman syndrome (search) completed enrollment with 129 patients.
Q3 2025 revenue reached $160 million, up 15% year-over-year, driven by Crysvita's $112 million contribution, with full-year guidance maintained at $640-670 million despite net losses of $180 million.
Ultragenyx Pharmaceutical Inc. has completed a rolling Biologics License Application (BLA) submission for DTX401, its AAV gene therapy for Glycogen Storage Disease Type Ia (search) (GSDIa), marking a significant regulatory milestone for the rare disease specialist. The submission, which began in August 2025 and concluded in Q4 2025, incorporates data from a randomized, placebo-controlled Phase 3 study demonstrating statistically significant and clinically meaningful reductions in daily cornstarch intake.
DTX401 Demonstrates Sustained Efficacy in Phase 3 Trial
The Phase 3 study for DTX401 showed compelling long-term results, with both the originally treated group (n=20) and crossover group (n=19) achieving a mean reduction in daily cornstarch intake of 61% at Week 96. The therapy's impact extended beyond metabolic improvements, with quality of life enhancements measured by the Patient Global Impression of Change (PGIC) scale. By Week 96, disease management improvements were reported in 83% (10/12) of patients in the original treatment group and 95% (18/19) of patients in the crossover group.
The initial 48-week data had already demonstrated statistically significant reductions in daily cornstarch intake compared with placebo, with longer-term results announced in September 2025 showing enhanced reductions during the crossover period.
Broad Pipeline Advances Across Multiple Rare Diseases
Beyond DTX401, Ultragenyx is advancing several late-stage programs targeting rare genetic conditions. The Phase 3 Orbit and Cosmic studies for UX143 (setrusumab) in osteogenesis imperfecta (search) are progressing toward final analyses, with data expected by the end of 2025. These trials evaluate setrusumab in pediatric and young adult patients over an 18-month treatment period.
For Angelman syndrome (search), the company completed enrollment in its global Phase 3 Aspire study for GTX-102 in July 2025, randomizing 129 patients across 28 sites. Data from this study are anticipated in the second half of 2026, with the supportive Phase 2/3 Aurora study expanding evaluation into additional genotypes and age groups.
The company also plans to resubmit its BLA for UX111 AAV gene therapy for Sanfilippo Syndrome Type A (search) in early 2026, following a Complete Response Letter from the FDA. The resubmission will include additional clinical data demonstrating durable treatment effects and a favorable safety profile.
Strong Revenue Growth Amid Continued Losses
Ultragenyx reported Q3 2025 revenue of $160 million, representing a 15% increase year-over-year. Crysvita (burosumab) led revenue generation with $112 million, including $47 million from Latin America and Turkey. Dojolvi (triheptanoin) contributed $24 million, while Evkeeza (evinacumab) generated $17 million, reflecting continued international launches.
Despite revenue growth, net losses widened to $180 million, or $1.81 per share, compared to $134 million in the prior-year quarter. The company maintained its 2025 revenue guidance of $640-670 million, representing 14%-20% growth compared to 2024.
Financial Position Strengthened Through Strategic Transaction
Ultragenyx secured $400 million through the sale of an additional 25% royalty interest in Crysvita sales in the U.S. and Canada to OMERS (search), with payments beginning in 2028. Under the agreement, OMERS will receive 30% of Crysvita's net sales in the U.S. and Canada once the 2022 royalty purchase agreement cap of 1.45 times the purchase price has been reached, with total payments limited to 1.55 times the 2025 purchase price.
As of September 30, 2025, the company held $447 million in cash, cash equivalents, and marketable debt securities, providing financial flexibility as multiple programs advance toward regulatory decisions over the next 12-18 months.