Ultragenyx Announces First Patient Dosed in Pivotal Phase 3 Aspire Study Evaluating GTX-102 in Angelman Syndrome

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Ultragenyx Pharmaceutical Inc.
Ultragenyx Pharmaceutical Inc.

Company on track to initiate the Aurora study to evaluate GTX-102 in other Angelman syndrome genotypes and in other age groups in 2025

NOVATO, Calif., Dec. 19, 2024 (GLOBE NEWSWIRE) -- Ultragenyx Pharmaceutical Inc. (NASDAQ: RARE), today 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.

"Initiation of patient dosing in our Phase 3 Aspire study represents an important step forward in the development of an effective, and much needed, treatment for patients and families affected by Angelman syndrome,” said Eric Crombez, M.D., chief medical officer at Ultragenyx. "Our goal with Aspire is to confirm the safety and clinical efficacy of GTX-102 in a large, randomized trial with a population that represents the majority of patients with Angelman syndrome. Additionally, the Aurora study will further assess safety and validate efficacy in patients with different genotypes and in younger and older patients."

The global Phase 3 Aspire study will enroll approximately 120 children ages 4 to 17 with Angelman syndrome with a genetically confirmed diagnosis of full maternal UBE3A gene deletion. Participants will be randomized 1:1 to receive GTX-102 by intrathecal injection via lumbar puncture or to the sham comparator group during the 48-week primary efficacy analysis period. Participants in the active treatment group will receive three, monthly 8 mg loading doses of GTX-102 followed by dosing in a maintenance period that will increase to a maximum dose of 14 mg of GTX-102 quarterly. Patients in the sham comparator group will be eligible to crossover onto treatment after Week 48 is complete. The primary endpoint will be improvement in cognition assessed by Bayley-4 cognitive raw score, and the key secondary endpoint will be the Multi-domain Responder Index (MDRI) across the five domains of cognition, receptive communication, behavior, gross motor function, and sleep.

“Angelman syndrome affects cognitive and motor function, making walking, communicating, and performing many everyday tasks more difficult for individuals living with Angelman syndrome. As a united community, ASF and FAST work together to further awareness and treatment of Angelman syndrome and are excited by all the recent progress in research and drug development. The initiation of the Phase 3 Aspire study by Ultragenyx is a significant achievement and something the community should celebrate,” stated Amanda Moore, chief executive officer at the Angelman Syndrome Foundation (ASF) and Ryan Fischer, chief operating officer at Foundation for Angelman Syndrome Therapeutics (FAST), in a joint statement.