Ultragenyx Pharmaceutical Inc. Doses First Patient in Groundbreaking Aurora Study for Angelman Syndrome
1. Expanding Treatment Opportunities for Angelman Syndrome
On October 30, 2025, Ultragenyx Pharmaceutical Inc. (NASDAQ: RARE) announced a significant milestone in the clinical development of GTX-102 (apazunersen), an investigational antisense oligonucleotide (ASO) designed to treat Angelman syndrome (AS). The company reported that the first patient has been dosed in the *Aurora* study (NCT07157254), which aims to evaluate the efficacy and safety of GTX-102 across a broader range of genotypes and age groups than previously explored in the Phase 3 *Aspire* study.
2. A Comprehensive Approach to Angelman Syndrome
The *Aurora* study is pivotal as it expands the treatment population for GTX-102 to include both younger and older patients with various non-deletion AS genotypes. Dr. Eric Crombez, Ultragenyx's Chief Medical Officer, emphasized the study's open-label basket design, which facilitates a comprehensive assessment of safety and efficacy across different demographics. "We recognize the importance of bringing this potential new treatment to all patients, across genotypes and ages, as quickly as possible," he stated.
The *Aspire* study had previously focused on patients aged 4 to 17 years with a genetically confirmed diagnosis of full maternal *UBE3A* gene deletion, representing the largest group of Angelman patients. The *Aurora* study aims to include approximately 60 participants aged 1 to less than 65 years, thereby encompassing a broader spectrum of individuals affected by this rare condition.
3. Study Design and Cohorts
The *Aurora* study is structured to enroll patients into one of four cohorts, each with specific age and genotype criteria:
| Cohort | Age(years) | Genotype | Primary Endpoint |
|---|---|---|---|
| A | ≥ 1 to < 4 | Deletion-type AS | Bayley-4 cognitive raw score |
| B | ≥ 4 to < 18 | Uniparental paternal disomy (UPD) and imprinting center defect (ICD) | Multi-domain Responder Index (MDRI) response |
| C | ≥ 18 to < 65 | All genotypes | MDRI response |
| D | ≥ 4 to < 18 | *UBE3A* gene mutation | MDRI response |
Cohorts A, B, and C will be single-arm only, while Cohort D will include a randomized component, with participants assigned to either the GTX-102 treatment group or a No Treatment group. All cohorts will undergo a 48-week primary efficacy period, after which the No Treatment group will have the opportunity to cross over to treatment.
4. Community Response and Impact
The announcement of the *Aurora* trial has been met with enthusiasm within the Angelman syndrome community. Amanda Moore, CEO of the Angelman Syndrome Foundation, and Ryan Fischer, COO of the Foundation for Angelman Syndrome Therapeutics, issued a joint statement expressing their appreciation for Ultragenyx's dedication to advancing research. "This study captures a broad spectrum of individuals living with Angelman syndrome and reflects a collective goal shared by our community—to ensure that clinical trial opportunities are available across ages and genotypes," they noted.
5. Background on GTX-102
GTX-102 (apazunersen) is delivered via intrathecal administration and is designed to target the *UBE3A-AS* to prevent the silencing of the paternal allele of the *UBE3A* gene. This innovative approach aims to reactivate the expression of the deficient protein associated with Angelman syndrome. The therapy has already received multiple designations from regulatory bodies, including Breakthrough Therapy Designation and Orphan Drug Designation from the FDA, underscoring its potential significance in addressing this orphan condition.
6. The Challenges of Angelman Syndrome
Angelman syndrome, a rare neurogenetic disorder, results from the loss of function of the maternally inherited allele of the *UBE3A* gene. The condition is characterized by severe cognitive and motor impairments, balance issues, and debilitating seizures, significantly impacting the quality of life for affected individuals. While the syndrome does not typically shorten lifespan, those diagnosed require continuous care and face challenges in daily living activities.
Despite the lack of approved therapies, the potential for symptom reversal has been demonstrated in adult animal models, suggesting that effective treatments may be possible at various life stages.
7. Conclusion: A Promising Future
Ultragenyx's commitment to developing GTX-102 for Angelman syndrome reflects a broader mission to address unmet medical needs in rare genetic disorders. With the initiation of the *Aurora* study, the company is poised to explore new avenues for treatment, offering hope to families affected by this complex condition. As the study progresses, stakeholders eagerly await data that could pave the way for new therapeutic options in Angelman syndrome.
