Major Phase 3 study for drug GTX-102 set for launch before the current year concludes
Ultragenyx Pharmaceutical is set to launch a Phase 3 clinical trial for its gene therapy candidate, GTX-102, by the end of 2024. This trial aims to improve cognition in people with Angelman syndrome, a rare genetic disorder caused by a mutation in the UBE3A gene.
The upcoming Phase 3 trial will enroll approximately 120 patients with a full maternal deletion, a group that tends to be on the more severe end of the Angelman syndrome spectrum. The trial will be a double-blind sham-controlled study, meaning neither researchers nor participants will know which patients are being given the treatment and which the placebo.
GTX-102 is an antisense oligonucleotide that targets the UBE3A antisense transcript, or UBE3A-AS, a molecule that keeps the paternal copy of the UBE3A gene from being active in cells. By inhibiting this molecule, GTX-102 aims to increase the expression of the functional UBE3A protein.
Ultragenyx is currently conducting a Phase 1/2 study called KIK-AS, which is testing multiple doses of GTX-102 in children with Angelman syndrome. This study finished recruitment earlier this year, with 74 patients enrolled. The KIK-AS study is expected to be completed by December.
Interim data from the KIK-AS study has been discussed with the FDA, highlighting improvement in cognition as assessed by the Bayley-4. Other measures of cognitive function, motor function, behaviour, sleep, and communication abilities will also be evaluated in the Phase 3 trial.
In addition to the Phase 3 trial in patients with a full UBE3A gene deletion, Ultragenyx plans to initiate a study to evaluate GTX-102 in patients with other mutations. The company has received positive feedback from both the U.S. Food and Drug Administration (FDA) and the European Medicines Agency regarding its planned Phase 3 trial design. Ultragenyx also plans to meet with regulators in Japan in the near future to review the trial design.
Further information about Ultragenyx's clinical trials can be found on the company's webpage for patients. Participants in the Phase 3 study will receive GTX-102 or a placebo for about one year, with the main goal of testing improvement in cognition as assessed by the Bayley-4. After the placebo-controlled part of the study ends, patients given the placebo will have the option to roll over into an extension part in which they would get active treatment.
The Phase 3 trial is a significant step forward in the development of a potential treatment for Angelman syndrome, a disorder that currently has no approved therapies. More information about the trial and how to participate can be found on Ultragenyx's website.
