This section highlights FDA-related milestones and regulatory updates for drugs developed by Ultragenyx Pharmaceutical (RARE).
Over the past two years, Ultragenyx Pharmaceutical has reported clinical trial outcomes, regulatory submissions, approvals, and other FDA events for drugs and therapies such as
DTX401, GTX-102, UX111, and UX143. For definitions of regulatory abbreviations such as NDA, BLA, or PDUFA, see the event status legend.
DTX401 - FDA Regulatory Timeline and Events
DTX401 is a drug developed by Ultragenyx Pharmaceutical for the following indication: Glycogen Storage Disease Type Ia (GSDIa).
This drug is under review by the U.S. Food and Drug Administration (FDA).
Below is a timeline of key regulatory milestones for this therapy.
- Drug:
- DTX401
- Announced Date:
- May 30, 2024
- Indication:
- Glycogen Storage Disease Type Ia (GSDIa)
Announcement
Ultragenyx Pharmaceutical announced positive topline results from the Phase 3 GlucoGene study (NCT05139316) evaluating DTX401, an investigational gene therapy for the treatment of patients aged eight years and older with glycogen storage disease type Ia (GSDIa).
AI Summary
Ultragenyx Pharmaceutical announced positive topline results from the Phase 3 GlucoGene study of its investigational gene therapy DTX401 for treating glycogen storage disease type Ia (GSDIa) in patients aged eight years and older. The study met its primary endpoint by achieving a statistically significant 41.3% reduction in daily cornstarch intake at Week 48 for the DTX401 group, compared to only 10.3% in the placebo group (p<0.0001). Furthermore, all patients receiving DTX401 saw a decrease in cornstarch use, with 68% experiencing a reduction of at least 30% and 37% seeing a reduction of 50% or more. Along with cornstarch reduction, key secondary endpoints—including fewer daily doses and maintained glucose control—were successfully met. The Phase 3 trial results support previous findings and indicate that DTX401 could offer a meaningful improvement in the quality of life for individuals managing GSDIa.
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GTX-102 - FDA Regulatory Timeline and Events
GTX-102 is a drug developed by Ultragenyx Pharmaceutical for the following indication: Angelman Syndrome.
This drug is under review by the U.S. Food and Drug Administration (FDA).
Below is a timeline of key regulatory milestones for this therapy.
- Drug:
- GTX-102
- Announced Date:
- June 27, 2025
- Indication:
- Angelman Syndrome
Announcement
Ultragenyx Pharmaceutical announced that it has received Breakthrough Therapy Designation from the U.S. Food and Drug Administration (FDA) for GTX-102 (apazunersen) as a treatment for Angelman syndrome.
AI Summary
Ultragenyx Pharmaceutical has achieved a significant milestone by receiving Breakthrough Therapy Designation from the U.S. Food and Drug Administration for its investigational treatment GTX-102 (apazunersen). This designation is a major step in the development of a potential therapy for Angelman syndrome, a rare neurogenetic disorder that affects cognitive, motor, and speech abilities.
The FDA breakthrough status highlights GTX-102’s promise in addressing serious symptoms of Angelman syndrome. It also triggers an expedited process for reviewing the drug’s safety and effectiveness data. Ultragenyx is moving quickly in its clinical program, including a global Phase 3 study enrolling children with a genetically confirmed diagnosis. Additionally, further evaluations in different genotypes and age groups are planned later in the year, offering hope to families and patients affected by this challenging condition.
Read Announcement- Drug:
- GTX-102
- Announced Date:
- December 19, 2024
- Indication:
- Angelman Syndrome
Announcement
Ultragenyx Pharmaceutical announced that the first patient has been dosed in the pivotal Phase 3 Aspire study (NCT06617429) evaluating the efficacy and safety of GTX-102, its investigational antisense oligonucleotide (ASO) for Angelman syndrome.
AI Summary
Ultragenyx Pharmaceutical announced that the first patient has been dosed in the pivotal Phase 3 Aspire study (NCT06617429), which tests GTX-102, an investigational antisense oligonucleotide designed for Angelman syndrome. The study will enroll around 120 children, aged 4 to 17, who have a genetically confirmed full maternal UBE3A gene deletion. During the 48-week evaluation period, participants are randomly assigned to either receive GTX-102 through intrathecal injections or be part of a sham comparator group, with the option to crossover after Week 48. The trial plans to assess the drug’s efficacy using improvements measured by the Bayley-4 cognitive raw score and other key indicators like communication, behavior, motor skills, and sleep. This development marks a significant step toward finding a much-needed treatment for individuals and families affected by Angelman syndrome.
Read Announcement- Drug:
- GTX-102
- Announced Date:
- July 24, 2024
- Estimated Event Date Range:
- July 24, 2024 - July 24, 2024
- Target Action Date:
- July 24, 2024
- Indication:
- Angelman Syndrome
Announcement
- Ultragenyx Pharmaceutical announced that the company will share the latest clinical data, regulatory progress and program next steps for GTX-102, its investigational antisense oligonucleotide for Angelman syndrome, on Wednesday, July 24, at the 2024 Angelman Syndrome Foundation (ASF) Family Conference and Research Symposium in Sandusky, Ohio.
AI Summary
Ultragenyx Pharmaceutical announced that it will present updated information on GTX‑102, its investigational antisense oligonucleotide for Angelman syndrome, at the 2024 Angelman Syndrome Foundation (ASF) Family Conference and Research Symposium in Sandusky, Ohio. The presentations on Wednesday, July 24, 2024, will cover the latest clinical data, recent regulatory progress, and next steps in the program for GTX‑102, a treatment designed to target the UBE3A antisense transcript that limits expression of the paternal UBE3A allele. During the conference, Ultragenyx will review the positive interim Phase 1/2 results and provide an update on plans to initiate a Phase 3 pivotal trial by the end of the year. The event will be livestreamed from the ASF website, ensuring that patients, researchers, and other stakeholders have access to the newest insights and future directions for GTX‑102.
Read Announcement- Drug:
- GTX-102
- Announced Date:
- July 17, 2024
- Estimated Event Date Range:
- October 1, 2024 - December 31, 2024
- Target Action Date:
- 2024-LATE
- Indication:
- Angelman Syndrome
Announcement
Ultragenyx Pharmaceutical announced that Phase 3 study on track to initiate by the end of this year
AI Summary
Ultragenyx Pharmaceutical has announced that its pivotal Phase 3 study for GTX‐102 is on track to begin by the end of this year. The study, designed as a global, randomized, double‐blind, sham‐controlled trial, will enroll about 120 patients with Angelman syndrome who have a full maternal UBE3A gene deletion. The primary endpoint of the trial will be an improvement in cognition measured by the Bayley-4 cognitive raw score. In addition, the study will assess a key secondary endpoint using the Multi-Domain Responder Index (MDRI), which evaluates responses across several areas, including communication, motor function, behavior, and sleep.
This FDA alignment on the study design and endpoints supports Ultragenyx’s commitment to rapidly advancing clinical research for Angelman syndrome. The company aims to potentially expand testing to include patients with other genetic mutations, ultimately broadening treatment options for more children and adults facing this challenging disorder.
Read Announcement- Drug:
- GTX-102
- Announced Date:
- July 17, 2024
- Indication:
- Angelman Syndrome
Announcement
Ultragenyx Pharmaceutical announced the successful completion of an end-of-Phase 2 (EoP2) meeting with the U.S. Food and Drug Administration (FDA), supporting its Phase 3 study plans for GTX-102, an antisense oligonucleotide for Angelman syndrome.
AI Summary
Ultragenyx Pharmaceutical announced that it successfully completed an end-of-Phase 2 meeting with the FDA, marking a key step in the company’s plans for a Phase 3 study of GTX-102. This experimental therapy is an antisense oligonucleotide intended to treat Angelman syndrome, a rare neurogenetic disorder. During the meeting, the FDA aligned with Ultragenyx on the study design, which will focus on key endpoints including improvement in cognition measured by the Bayley-4 score and additional assessment using the Multi-Domain Responder Index (MDRI).
The phase 3 trial is designed as a global, randomized, double-blind, sham-controlled study, aiming to quickly enroll approximately 120 patients with a full maternal UBE3A gene deletion. This FDA-endorsed study design is expected to allow rapid initiation of the pivotal trial by the end of the year, potentially expanding treatment options for children and adults affected by this devastating disease.
Read Announcement- Drug:
- GTX-102
- Announced Date:
- April 15, 2024
- Indication:
- Angelman Syndrome
Announcement
Ultragenyx Pharmaceutical announced new data from the Phase 1/2 study of GTX-102 for the treatment of Angelman syndrome. Patients in Expansion Cohorts A & B treated with a set dose and regimen of GTX-102 showed rapid and clinically meaningful improvement across multiple domains consistent with or exceeding Dose-escalation Cohorts 4-7 data at Day 170.
AI Summary
Ultragenyx Pharmaceutical announced promising new Phase 1/2 study data for GTX-102 in treating Angelman syndrome. In Expansion Cohorts A and B, patients received a set dose and regimen of GTX-102 and demonstrated rapid, clinically meaningful improvements across multiple domains at Day 170. These results not only match but sometimes exceed the benefits seen in previous Dose-escalation Cohorts 4–7 at the same timepoint. The improvements were measured in areas such as cognition, behavior, sleep, and communication, with early signs of better motor skills also noted. The data suggest that GTX-102 may offer significant, rapid developmental gains, potentially leading to increased patient independence. This development is an important step forward, especially since no approved disease-modifying treatments currently exist for Angelman syndrome. The promising findings add to the growing evidence that GTX-102 could be a beneficial therapy for patients facing this challenging condition.
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UX111 - FDA Regulatory Timeline and Events
UX111 is a drug developed by Ultragenyx Pharmaceutical for the following indication: For Sanfilippo syndrome type A (MPS IIIA).
This drug is under review by the U.S. Food and Drug Administration (FDA).
Below is a timeline of key regulatory milestones for this therapy.
- Drug:
- UX111
- Announced Date:
- February 18, 2025
- Indication:
- For Sanfilippo syndrome type A (MPS IIIA)
Announcement
Ultragenyx Pharmaceutical announced the U.S. Food and Drug Administration (FDA or the Agency) has accepted for review the Biologics License Application (BLA) seeking accelerated approval for UX111 (ABO-102) AAV gene therapy as a treatment for patients with Sanfilippo syndrome type A (MPS IIIA).
AI Summary
Ultragenyx Pharmaceutical announced that the U.S. Food and Drug Administration (FDA) has accepted its Biologics License Application (BLA) for review. The application seeks accelerated approval for UX111 (ABO-102), an AAV gene therapy designed to treat Sanfilippo syndrome type A (MPS IIIA), a rare, fatal lysosomal storage disease that primarily affects the brain.
The FDA has granted Priority Review and set a Prescription Drug User Fee Act (PDUFA) action date of August 18, 2025. This milestone is an important step toward providing the first-ever treatment for patients with MPS IIIA. Ultragenyx is preparing to launch the therapy if approved, marking significant progress for families facing this devastating condition and paving the way for future advancements in treating metabolic brain diseases.
Read Announcement- Drug:
- UX111
- Announced Date:
- February 18, 2025
- Estimated Event Date Range:
- August 18, 2025 - August 18, 2025
- Target Action Date:
- August 18, 2025
- Indication:
- For Sanfilippo syndrome type A (MPS IIIA)
Announcement
Ultragenyx Pharmaceutical Inc announced that The FDA granted the BLA Priority Review with a Prescription Drug User Fee Act (PDUFA) action date of August 18, 2025.
AI Summary
Ultragenyx Pharmaceutical Inc. announced that the U.S. Food and Drug Administration (FDA) granted Priority Review for its Biologics License Application (BLA) for UX111, a gene therapy aimed at treating Sanfilippo syndrome type A. This review comes under the Prescription Drug User Fee Act (PDUFA), with an action date set for August 18, 2025. The Priority Review designation means that the FDA will evaluate the application more quickly than standard reviews.
The decision marks an important milestone in the effort to offer the first-ever treatment for this rare and severe neurological disorder. UX111 is designed to address the underlying enzyme deficiency, and if approved, it could greatly improve the lives of patients and their families. Ultragenyx’s commitment to advancing therapies for serious rare diseases is reflected in this significant regulatory step.
Read Announcement- Drug:
- UX111
- Announced Date:
- February 5, 2025
- Indication:
- For Sanfilippo syndrome type A (MPS IIIA)
Announcement
Ultragenyx Pharmaceutical announced new data demonstrating treatment with UX111 (ABO-102) AAV gene therapy led to a statistically significant improvement in the Bayley-IIIi raw scores for the subdomains of cognition, receptive communication and expressive communication in patients with Sanfilippo syndrome type A (MPS IIIA) compared to natural history data from untreated patients.
AI Summary
Ultragenyx Pharmaceutical recently released new data showing that treatment with UX111 (ABO-102) gene therapy significantly improved developmental skills in patients with Sanfilippo syndrome type A (MPS IIIA). In the pivotal Transpher A study, patients receiving UX111 showed a +22.7 point treatment effect (p<0.0001) on the Bayley-III cognitive raw scores compared to natural history data from untreated children aged 24 to 60 months. The therapy also led to statistically better scores in receptive and expressive communication. These improvements highlight UX111’s potential to not only slow the disease’s progression but also help patients gain new developmental abilities. The findings, which also correlated with a marked reduction in heparan sulfate in cerebrospinal fluid, were gathered from both the modified intent-to-treat group and older children with advanced disease, underlining the therapy’s broad impact across different age groups.
Read Announcement- Drug:
- UX111
- Announced Date:
- December 19, 2024
- Indication:
- For Sanfilippo syndrome type A (MPS IIIA)
Announcement
Ultragenyx Pharmaceutical announced the submission of a Biologics License Application (BLA) to the U.S. Food and Drug Administration (FDA or the Agency) seeking accelerated approval for UX111 (ABO-102) AAV gene therapy as a treatment for patients with Sanfilippo syndrome type A (MPS IIIA).
AI Summary
Ultragenyx Pharmaceutical recently announced the submission of a Biologics License Application (BLA) to the U.S. Food and Drug Administration. The company is seeking accelerated approval for its new AAV gene therapy, UX111 (also known as ABO‑102), designed to treat patients with Sanfilippo syndrome type A (MPS IIIA). This innovative therapy targets the underlying genetic defect responsible for this severe disorder, which leads to significant developmental delays and neurological challenges.
The BLA submission marks a major step forward in addressing the urgent unmet needs of patients with MPS IIIA. If approved, UX111 could offer a much-needed treatment option, potentially improving patient outcomes and quality of life. Ultragenyx is committed to advancing transformative therapies and working closely with the FDA to bring this promising treatment to those affected by this rare genetic condition.
Read Announcement- Drug:
- UX111
- Announced Date:
- June 12, 2024
- Indication:
- For Sanfilippo syndrome type A (MPS IIIA)
Announcement
Ultragenyx Pharmaceutical announced that the company held a successful meeting with the U.S. Food and Drug Administration (FDA or the Agency) during which the company reached agreement with the Agency that cerebral spinal fluid (CSF) heparan sulfate (HS) is a reasonable surrogate endpoint that could support submission of a biologics license application (BLA) seeking accelerated approval for UX111 (ABO-102) AAV gene therapy for the treatment of Sanfilippo syndrome (MPS IIIA).
AI Summary
Ultragenyx Pharmaceutical announced that in a recent meeting with the FDA, the agency agreed that measuring heparan sulfate in the cerebrospinal fluid (CSF HS) is a reasonable surrogate endpoint for its gene therapy, UX111 (ABO-102). This agreement is a key step in the development of the treatment for Sanfilippo syndrome (MPS IIIA), a rare, fatal genetic disorder that primarily affects the central nervous system and causes rapid neurodegeneration in children. Using CSF HS as a biomarker, Ultragenyx plans to support a biologics license application (BLA) seeking accelerated approval for UX111. This decision brings hope to families affected by the disease, as it could speed up the availability of a much-needed therapy. The company intends to finalize the BLA details in a pre-submission meeting with the FDA, aiming to file later this year or early next year.
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UX143 (setrusumab) - FDA Regulatory Timeline and Events
UX143 (setrusumab) is a drug developed by Ultragenyx Pharmaceutical for the following indication: Osteogenesis Imperfecta (OI).
This drug is under review by the U.S. Food and Drug Administration (FDA).
Below is a timeline of key regulatory milestones for this therapy.
- Drug:
- UX143 (setrusumab)
- Announced Date:
- July 9, 2025
- Indication:
- Osteogenesis Imperfecta (OI)
Announcement
Ultragenyx Pharmaceutical announced that the randomized, placebo-controlled Phase 3 portion of the Orbit study evaluating UX143 (setrusumab) in pediatric and young adult patients with osteogenesis imperfecta (OI) is progressing toward a final analysis consistent with the original plan, around the end of the year.
AI Summary
Ultragenyx Pharmaceutical announced that the Phase 3 portion of the Orbit study, which is testing UX143 (setrusumab) in pediatric and young adult patients with osteogenesis imperfecta (OI), is on track for final analysis as planned. This randomized, placebo-controlled study is designed to evaluate the benefits of setrusumab in reducing fracture rates by increasing bone mass and strength. The Data Monitoring Committee has noted that the safety profile of UX143 remains acceptable, allowing the study to continue until its planned conclusion. Investigators and families involved in the study have provided positive feedback regarding the treatment’s effectiveness. The final analysis is expected to be completed around the end of the year after patients have received at least 18 months of therapy, advancing the team's efforts to deliver a potentially impactful treatment for OI.
Read Announcement- Drug:
- UX143 (setrusumab)
- Announced Date:
- September 26, 2024
- Indication:
- Osteogenesis Imperfecta (OI)
Announcement
Ultragenyx Pharmaceutical announced that it will present seven abstracts related to its ongoing late-stage program evaluating setrusumab (UX143) and osteogenesis imperfecta (OI), including a late-breaker oral presentation of the 14-month data from the Phase 2/3 Orbit study, at the American Society for Bone and Mineral Research (ASBMR) 2024 Annual Meeting.
AI Summary
Ultragenyx Pharmaceutical announced that it will present seven abstracts at the American Society for Bone and Mineral Research (ASBMR) 2024 Annual Meeting. The focus of these presentations is its late-stage program evaluating setrusumab (UX143) for osteogenesis imperfecta (OI). Among these is a late-breaker oral presentation, which will detail the 14‐month data from the Phase 2/3 Orbit study. This data highlights a rapid and clinically meaningful increase in bone mineral density along with a reduction in the annualized fracture rate, signaling promising progress in addressing OI’s challenges. Held in Toronto from September 27-30, 2024, the meeting will provide insights into the effects of setrusumab on improved bone formation and enhanced patient outcomes. According to Ultragenyx’s chief medical officer, these presentations aim to deepen the understanding of OI and underscore the urgent need for innovative treatment options for patients living with this challenging condition.
Read Announcement- Drug:
- UX143 (setrusumab)
- Announced Date:
- June 11, 2024
- Indication:
- Osteogenesis Imperfecta (OI)
Announcement
Ultragenyx Pharmaceutical Inc. announced positive 14-month results from the Phase 2 portion of the ongoing Phase 2/3 Orbit study (NCT05125809) demonstrating that, as of a May 24, 2024 data cut-off date, treatment with setrusumab (UX143) continued to significantly reduce incidence of fractures in patients with OI with at least 14 months of follow-up.
AI Summary
Ultragenyx Pharmaceutical Inc. announced positive 14-month results from the Phase 2 portion of its ongoing Phase 2/3 Orbit study (NCT05125809) for patients with osteogenesis imperfecta (OI). As of a May 24, 2024 data cut-off, treatment with setrusumab (UX143) led to a significant reduction in fractures. Notably, patients experienced a 67% drop in the annualized fracture rate, with the median rate reducing to 0.00 (p=0.0014) after at least 14 months of follow-up.
In addition to fewer fractures, setrusumab treatment resulted in meaningful gains in bone health. The lumbar spine bone mineral density (BMD) increased by an average of 22% from baseline at 12 months, with an accompanying mean improvement in Z-score of +1.25 (both statistically significant at p<0.0001). These improvements suggest that the treatment is not only safe but continues to offer ongoing benefits over time.
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