Ultragenyx Acquires GeneTx, Phase 1/2 Trial of GTX-102 Gene Therapy

Margarida Maia, PhD avatar

by Margarida Maia, PhD |

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GeneTx Biotherapeutics, a company set up by the Foundation for Angelman Syndrome Therapeutics (FAST), has been acquired by Ultragenyx Pharmaceutical, which will take over the ongoing GTX-102 clinical program for Angelman syndrome.

The two companies began working together in 2019, and they jointly launched a Phase 1/2 clinical trial (NCT04259281) of GTX-102, an investigational gene therapy for Angelman, at sites in the U.K., Canada, and the U.S.

Ultragenyx put into effect an exclusive right to buy GeneTx’s shares, assuming full control of the study and the GTX-102 clinical program.

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Trial: Gene Therapy GTX-102 Shows Promise in Angelman Children

“What happened … is why FAST was founded, why we started GeneTx, and why we donate and fundraise: to discover and accelerate promising therapies for [Angelman syndrome],” John Schlueter, chairperson of the board at FAST, said in a press release.

“Our approach, from funding frontline discoveries through preclinical studies, to forging strategic partnerships in the biotechnology industry, aims to quickly advance translational research, so that families living with [Angelman syndrome] move closer to potentially transformative treatments,” Schlueter added.

GTX-102 trial enrolling at sites in US, UK, Canada

Proceeds from the sale will be used to support disease research and programs, FAST stated in the release.

Angelman is caused by the absence or malfunction of the ubiquitin protein ligase E3A (UBE3A) gene. This gene encodes the information needed to make ubiquitin protein ligase E3A (UBE3A), a protein that tags other proteins for recycling within cells. This helps keep cells healthy by getting rid of unwanted or poorly working proteins.

People normally inherit one copy of the UBE3A gene from their mother and another copy from their father. Both copies are turned on, becoming active, in most cells in the body. But in certain brain cells, only the mother’s copy is active.

This means that when the maternal UBE3A gene is dysfunctional, brain cells lack the instructions typically provided by the gene for proper recycling, leading to the symptoms of Angelman syndrome.

GTX-102 is an antisense oligonucleotide — a short string of DNA or RNA that can control how much of a protein is made by cells. It can pair with another antisense oligonucleotide occurring naturally within the brain cells, called UBE3A-AS, which normally turns off, or silences, the paternal copy of UBE3A.

This is expected to activate the paternal copy of UBE3A so that brain cells can make more of properly working UBE3A, preventing or easing disease symptoms.

Interim trial data supported the potential of GTX-102, given intrathecally (into the spinal canal), to lessen disease severity and improve function in 11 treated children and adolescents with Angelman due to a complete deletion of the mother’s copy of UBE3A. Improvements were seen at six months of follow-up in various aspects: behavior, gross and fine motor function, expressive and receptive communication, and sleep.

Enrollment of eligible patients, ages 4 to 17, in this Phase 1/2 trial is continuing, and study contact and site information is available. The open-label study aims to recruit 83 children.

“We are most grateful to the entire Angelman syndrome community, our phenomenal scientific team, and our incredible families who work tirelessly to help raise the funds to advance these promising developments in [Angelman syndrome] research,” said Allyson Berent, chief science officer for FAST.

“The effort it takes to make a difference in the therapeutic landscape for those living with Angelman syndrome has been a journey of a lifetime, and this is an exciting milestone in the journey,” Berent added.