GeneTx and Ultragenyx Announce Presentation of Phase 1/2 Data on Investigational GTX-102 in Patients with Angelman Syndrome

Results presented at Foundation for Angelman Syndrome Therapeutics (FAST) Global Summit

Additional data, including EEG findings, support prior initial indications of activity and there were no new adverse events

SARASOTA, Fla. and NOVATO, Calif., Dec. 05, 2020 (GLOBE NEWSWIRE) -- GeneTx Biotherapeutics LLC and Ultragenyx Pharmaceutical Inc. (NASDAQ: RARE), companies partnered in the development of intrathecally administered GTX-102, an investigational treatment for Angelman syndrome, today announced the presentation of data from the Phase 1/2 study of GTX-102 at the Foundation for Angelman Syndrome Therapeutics (FAST) Global Summit. Details regarding the scientific basis for GTX-102 targeting in Angelman syndrome were presented along with additional supportive clinical data on EEG and other endpoints, along with further description of the safety events. Additional nonclinical study data were included showing substantial silencing activity at low repeat doses along with chronic nonclinical safety data at higher doses compared to dosing in the human study. Presentations were made by Scott Stromatt, M.D., Chief Medical Officer of GeneTx and Elizabeth M. Berry-Kravis, M.D., Ph.D. Professor of Pediatrics, Neurological Sciences and Biochemistry at Rush University on Friday December 4^th, and by Emil D. Kakkis, M.D., Ph.D., Chief Executive Officer and President of Ultragenyx, on Saturday, December 5^th.

“I am excited by the preliminary findings presented at the FAST scientific symposium. A tremendous amount of work was put into understanding the UBE3A-AS transcript and developing GTX-102, so it is great to see how those efforts have translated into initial indications of effect in the clinical study in patients with Angelman syndrome,” said Scott V. Dindot, Ph.D., Associate Professor, Texas A&M University, and Executive Director, Molecular Genetics at Ultragenyx. “I am grateful to be a part of this endeavor, and I look forward to seeing what the future holds for the Angelman syndrome community.”

“GTX-102 demonstrates a paternal UBE3A gene targeting strategy can result in substantial clinical activity and in a more rapid time frame than we expected,” stated Dr. Scott Stromatt. “We better understand the serious adverse events reported with GTX-102 at higher doses and we see a way forward to redose patients and to enroll new patients into the clinical trial. We are working with FDA to reach agreement on a modified trial design.”