rivunatpagene miziparvovec (UX701) / Ultragenyx - LARVOL DELTA

Management of acute infusion-related reactions in AAV gene therapy guided by mechanistic insight (ASGCT 2026) - "Methods IRRs were observed in two participants who received an AAV8 gene therapy (DTX401) for Glycogen Storage Disease Type Ia and in one participant who received an AAV9 gene therapy (UX701) for Wilson’s Disease. AAV gene therapy IRRs appear to be rate-related and possibly driven by complement activation, not IgE-mediated mechanisms. Conclusion The risk of IRRs can be mitigated by a slow, staged infusion, allowing successful administration of a therapeutic gene therapy dose."

Gene therapy • Gene Therapies • Hepatology • Immunology • Metabolic Disorders • Movement Disorders

UX701 GENE THERAPY FOR WILSON DISEASE: RESULTS: FROM THE PHASE 1/2 PORTION OF CYPRUS2+ (AASLD 2025) - P1/2 | "Cyprus2+ is the first systematic evaluation of long-term hepatic transgene expression in subjects receiving gene therapy. Durable changes in Cu homeostasis were observed along with new ATP7B apical expression. Most were able to discontinue SOC medications."

Gene therapy • P1/2 data • Fibrosis • Gastrointestinal Disorder • Gene Therapies • Genetic Disorders • Hepatology • Immunology • Inflammation • Liver Failure • Metabolic Disorders • Movement Disorders • ATP7B

A Phase 1/2/3 Study of UX701 Gene Therapy in Adults With Wilson Disease (clinicaltrials.gov) - P1/2 | N=82 | Active, not recruiting | Sponsor: Ultragenyx Pharmaceutical Inc | Recruiting ➔ Active, not recruiting

Enrollment closed • Gene Therapies • Genetic Disorders • Metabolic Disorders • Movement Disorders

Late-stage Development and Upstream Process Characterization of UX701 AAV Gene Therapy for Wilson Disease (ASGCT 2025) - "We have successfully risk assessed the UX701 upstream process, qualified a SDM, and characterized the process design space for our first Pinnacle PCL™ program. We have generated a comprehensive set of process-product relationships for UX701 as well as our rAAV platform, which will benefit other ongoing PCL™ programs in our clinical pipeline. These studies will continue to help us understand and mitigate operational and quality risks, which are critical for successful implementation of a robust commercial manufacturing process to provide consistent product quality throughout the product's lifecycle."

Gene therapy • Gene Therapies • Genetic Disorders • Hepatology • Infectious Disease • Metabolic Disorders • Movement Disorders • ATP7B

Characterization of High and Low rAAV Producer Cell Populations in Pinnacle PCL using Single Cell RNA Sequencing (ASGCT 2025) - "The Pinnacle Producer Cell Line (PCL) system is capable of supporting scalable 2000L clinical grade rAAV production and has been used to generate material for the ongoing UX701 clinical trial for Wilson Disease...Finally, vector constructs with engineered secondary structure have been analyzed to understand key differences between our high and low producing PCL clones. Disease Focus of Abstract:None"

Clinical • Genetic Disorders • Hepatology • Metabolic Disorders • Movement Disorders

The Seropositivity Dilemma for AAV Gene Therapy (ASGCT 2025) - "To explore the impact of seropositivity further, we characterized the total binding antibody titers in individuals with Ornithine Transcarbamylase Deficiency (OTC), Glycogen Storage Disease type Ia (GSDIa) and Wilson Disease (WD), as these are the populations that are under investigation for DTX301, DTX401 and UX701 AAV gene therapies, respectively. These data support further investigation into more frequent AAV TAb testing and will inform discussions about the possibility of dosing low TAb+ individuals in future AAV GT trials. Disease Focus of Abstract:Rare Diseases"

Gene therapy • Gene Therapies • Hepatology • Metabolic Disorders • Movement Disorders • Rare Diseases

Optimization of Plasmid Cloning Methodology to Support Continued Development of the Pinnacle PCL™ Gene Therapy Platform (ASGCT 2025) - "The Pinnacle PCL system is capable of supporting scalable 2000L clinical grade rAAV production and has been used to generate material for the ongoing UX701 clinical trial for Wilson Disease...This work has facilitated ongoing efforts to improve rAAV productivity and quality via higher throughput plasmid cloning. Disease Focus of Abstract:None"

Gene therapy • Gene Therapies • Hepatology • Metabolic Disorders • Movement Disorders

A Phase 1/2/3 Study of UX701 Gene Therapy in Adults With Wilson Disease (clinicaltrials.gov) - P1/2 | N=82 | Recruiting | Sponsor: Ultragenyx Pharmaceutical Inc | Active, not recruiting ➔ Recruiting | Trial completion date: Nov 2031 ➔ Mar 2034 | Trial primary completion date: Aug 2026 ➔ Mar 2029

Enrollment open • Trial completion date • Trial primary completion date • Gene Therapies • Genetic Disorders • Metabolic Disorders • Movement Disorders

Study of UX701 Gene Transfer for the Treatment of Wilson Disease (clinicaltrials.gov) - P1/2 | N=78 | Active, not recruiting | Sponsor: Ultragenyx Pharmaceutical Inc | Trial completion date: Jan 2031 ➔ Nov 2031 | Trial primary completion date: Jan 2026 ➔ Aug 2026

Trial completion date • Trial primary completion date • Gene Therapies • Genetic Disorders • Hepatology • Metabolic Disorders • Movement Disorders • ATP7B

Study of UX701 Gene Transfer for the Treatment of Wilson Disease (clinicaltrials.gov) - P1/2 | N=78 | Active, not recruiting | Sponsor: Ultragenyx Pharmaceutical Inc | Recruiting ➔ Active, not recruiting

Enrollment closed • Gene Therapies • Genetic Disorders • Hepatology • Metabolic Disorders • Movement Disorders • ATP7B

"Pleased to share @craiglammertIU @IUGastro dosed UX701 AAV9-ATP7B gene therapy # Wilson's ds @IUMedSchool yesterday. 2nd in the nation. Not our discovery, but offering a potential cure to patients is special." (,@nagachalasani)

Clinical • Gene Therapies • ATP7B