"Rush for treatment prompts boost in participant sign-ups for GTX-102 trial"
In a significant development for those affected by Angelman syndrome, Ultragenyx Pharmaceutical announced that its experimental therapy, GTX-102 (apazunersen), has completed enrollment in the Phase 3 clinical trial. This follows the successful completion of the Phase 1/2 study, known as the KIK-AS study, which indicated that GTX-102 was generally well-tolerated and led to improvements in cognition.
The Phase 3 trial, named the Aspire study (NCT06617429), enrolled approximately 129 participants aged 4-17 with a completely missing maternal UBE3A copy. The main goal of the Aspire study is to assess the impact of treatment on the Bayley-4 Cognitive Raw Score. Other measures assessed include tests of motor function and behaviour, along with safety outcomes.
The Aspire study achieved full enrollment in just seven months, starting from December 2021, thanks in part to support from the Angelman syndrome community. The continued developmental gains observed in the Phase 1/2 study provide a strong foundation for advancing the program with the potential to address the underlying genetic cause of Angelman syndrome and enhance the quality of life for children living with the condition.
GTX-102 is an antisense oligonucleotide designed to inhibit the mechanism that silences the paternal UBE3A gene copy, turning on the healthy version from the father. It is administered by intrathecal injection, into the spinal canal.
Ultragenyx Pharmaceutical, the developer of GTX-102, is planning to launch a separate study named Aurora to test GTX-102 in other ages and mutation types. The results of the Aspire study are expected in late 2026.
It is important to note that Eric Crombez, MD, the chief medical officer at Ultragenyx, has been involved in insider trading activities. In 2025, he sold shares of Ultragenyx Pharmaceutical, and he has also made significant stock transactions, including selling 4.72 thousand shares in a recent trade.
Angelman syndrome is caused by mutations in the UBE3A gene. In nerve cells, the copy of the UBE3A gene inherited from the father is usually inactive in people with Angelman syndrome. People with Angelman syndrome have a missing or faulty copy of the gene inherited from the mother, leaving them with no functional UBE3A gene in their nerve cells.
As the Aspire study progresses, the scientific community will closely watch the results to determine the potential of GTX-102 as a treatment for Angelman syndrome. The launch of the Aurora study later this year by Ultragenyx Pharmaceutical further underscores the company's commitment to finding a cure for this debilitating condition.
