-First Gene Therapy Trial for Angelman Syndrome
-Orphan Drug Designation Granted for MVX-220
MIDDLETON, Mass., Nov. 6, 2025 /PRNewswire/ -- MavriX Bio, a clinical-stage biotechnology company focused on the development of transformative genetic therapies for Angelman syndrome (AS), today announced that the first patient has been dosed in the Phase 1/2 ASCEND-AS clinical trial of MVX-220, an investigational gene therapy for AS.
The ASCEND-AS trial (NCT07181837) represents the first clinical evaluation of a gene therapy for AS. Supported by the Foundation for Angelman Syndrome Therapeutics (FAST) and AS2Bio, MavriX Bio developed MVX-220 to restore functional expression of the UBE3A gene in neurons using targeted AAV delivery to the central nervous system. The trial will evaluate safety, tolerability, and efficacy of MVX-220 in both adult and pediatric participants with different AS genotypes, including deletion, uniparental disomy, and imprinting center defects.
In addition to this important clinical milestone, MavriX Bio announced that the U.S. Food and Drug Administration (FDA) granted Orphan Drug Designation for MVX-220 for treatment of AS. Orphan Drug Designation is a status granted to support the development of investigational therapies intended for the treatment of rare diseases that affect fewer than 200,000 people in the US. This designation confers various benefits related to market exclusivity, waiver or reduction of application fees, and certain tax credits.
"Dosing our first participant in the ASCEND-AS trial is a critical step in evaluating the potential of gene targeted therapies for AS, made possible by the unwavering dedication of the Angelman community, our scientific collaborators, and development partners," said Jennifer Panagoulias, Chief Operating Officer of MavriX Bio. "This milestone, combined with the recent receipt of Orphan Drug Designation from the FDA, reinforces the promise of MVX-220 and the urgency driving our work."
"This trial represents a new era in Angelman syndrome research," said Dr. Elizabeth Berry-Kravis, MD, PhD, Professor of Pediatrics, Neurological Sciences, Anatomy and Cell Biology and Director of the RUSH Pediatric Neurosciences F.A.S.T Center for Translational Research at Rush University Medical Center, and Principal Investigator for the ASCEND-AS trial. "For the first time, we are testing a one-time therapeutic approach that directly targets the genetic root cause of Angelman syndrome by replacing UBE3A expression in neurons. This is a meaningful step forward for the entire Angelman community, serving as an example for other genetic neurodevelopmental disorders."
Developed at the University of Pennsylvania with funding from FAST, MVX-220 was advanced through AS2Bio's drug development accelerator and licensed to MavriX Bio for clinical development following a research collaboration with GEMMABio.
Angelman syndrome affects approximately 1 in 12,000–20,000 individuals worldwide and currently has no approved disease-modifying treatments.
About MVX-220
MVX-220 is an investigational gene therapy designed to restore functional expression of the UBE3A gene in neurons, the underlying cause of AS, using targeted AAV delivery. The first-in-human study ASCEND-AS will evaluate the safety, tolerability, and efficacy of MVX-220 in adult and pediatric individuals living with various genotypes of AS, including deletion, uniparental disomy (UPD) and imprinting center defects (ID).
MVX-220 was developed at the University of Pennsylvania with full support from FAST, which funded both the development and nonclinical research activities. The program was subsequently licensed to MavriX Bio, a portfolio company of FAST's drug development accelerator AS2Bio.
About ASCEND-AS
ASCEND-AS (NCT07181837) is a Phase 1/2 first-in-human clinical study of MVX-220 in Angelman syndrome that will evaluate safety and tolerability with additional clinical assessments in US participants. Further details can be referenced at https://clinicaltrials.gov/study/NCT07181837?term=NCT07181837&rank=1
About MavriX Bio
MavriX Bio is a clinical-stage biotechnology company developing genetic medicines for severe neurological disorders with high unmet need. The company advances programs from discovery through early clinical development and collaborates with academic centers, investigators, and patient organizations to accelerate responsible innovation. For more information, visit mvxbio.com.
About AS2Bio
AS2Bio is drug development accelerator established by FAST to create an integrated approach to drug development in Angelman syndrome, leveraging collective expertise, resources, data and vital networks to provide a "bridge" for new technologies so they can move from proof-of-concept to early-stage clinical trials. MavriX Bio is one of the portfolio companies that AS2Bio supports. For more information, please visit as2bio.com.
About the Foundation for Angelman Syndrome Therapeutics (FAST)
FAST is the leading patient advocacy organization working to cure Angelman syndrome. As the largest non-governmental funder of AS research in the world, FAST's goal is to drive forward transformative research and development programs as efficiently as possible for those living with AS — regardless of age or genotype. Learn more at cureangelman.org.
About Angelman Syndrome
Angelman syndrome is a rare, non-degenerative neurogenetic disorder caused by loss of function of the UBE3A gene in neurons. Individuals with AS experience severe developmental delays, speech impairment, seizures, sleep challenges, and motor difficulties. It affects approximately 1 in 12,000–20,000 people worldwide. There are currently no approved disease-modifying treatments.
SOURCE AS2Bio
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