Aeglea BioTherapeutics Announces Publication of 20 Week Data from Phase 1/2 and Open-Label Extension Studies of Pegzilarginase for the Treatment of Arginase 1 Deficiency in the Journal of Inherited Metabolic Disease

AUSTIN, Texas, July 14, 2021 /PRNewswire/ -- Aeglea BioTherapeutics, Inc. (NASDAQ: AGLE), a clinical-stage biotechnology company developing a new generation of human enzyme therapeutics as innovative solutions for rare metabolic diseases, today announced the publication of 20 week data from the Phase 1/2 clinical trial of pegzilarginase for the treatment of Arginase 1 Deficiency (ARG1-D), a rare, progressive and devastating disease characterized by high levels of the amino acid arginine. Pegzilarginase is a novel, recombinant human arginase 1 enzyme designed to lower levels of arginine that is also being investigated in PEACE, an ongoing Phase 3 pivotal trial for the treatment of ARG1-D.

The article, titled "Clinical Effect and Safety Profile of Pegzilarginase In Patients with Arginase 1 Deficiency," was lead authored by Dr. George Diaz, Division Chief of Medical Genetics in the Department of Genetics & Genomic Sciences at the Icahn School of Medicine at Mt. Sinai, New York, NY, and has been published in the July issue of the Journal of Inherited Metabolic Disease. The full publication can be accessed at https://onlinelibrary.wiley.com/doi/epdf/10.1002/jimd.12343.

"This trial is the first time clinical outcomes have been used to assess the impact of ARG1-D and provides critical information in our understanding of the disease burden and potential for its treatment," said Dr. Diaz. "Given the serious and progressive nature of this condition, understanding how to limit or even reverse the course of the disease has the potential to fundamentally alter how we treat ARG1-D and improve the lives of patients and their families."

The Phase 1/2 trial was designed to assess the safety and efficacy of pegzilarginase for the treatment of ARG1-D. These results represent data after only 20 doses of pegzilarginase. Key results from the study include:

• Pegzilarginase was well tolerated, and the rates of treatment-related adverse events decreased over time.
• Common treatment-related adverse events included hypersensitivity, vomiting, hyperammonemia, pruritus and abdominal pain.
• Serious treatment-related adverse events included hypersensitivity and hyperammonemia, which were infrequent, managed with standard treatment and did not lead to any patient discontinuations.
• All patients demonstrated a marked and sustained reduction in plasma arginine.
• By Dose 20, 13 of 14 (93%) patients had arginine levels