 Pegzilarginase Showed Durable Clinical Response and Sustained Reduction in Plasma Arginine at 56 Week Analysis of Phase 12 Open-Label Extension Study Initiated Phase 12 Clinical Trial of ACN00177 for the Treatment of HomocystinuriaAUSTIN, Texas, Aug. 10, 2020 GLOBE NEWSWIRE -- Aeglea BioTherapeutics, Inc. NASDAQ:AGLE, a clinical-stage biotechnology company developing a new generation of human enzyme therapeutics as innovative solutions for rare and other high-burden diseases, today reported its second quarter 2020 financial results, and provided recent corporate and program highlights.Despite the operating challenges posed by the global pandemic, we continued to advance our pegzilarginase program in the first half of the year. The presentation of long-term data showing sustained lowering of arginine levels and durable clinical response with pegzilarginase treatment, as well as progress in our patient identification efforts, reinforce our belief in its potential as a life-changing therapy for those with Arginase 1 Deficiency and lay a strong foundation for the commercial launch of pegzilarginase, said Anthony Quinn, M.B Ch.B, Ph.D., president and chief executive officer of Aeglea. Additionally, we initiated our Phase 12 clinical trial of ACN00177 for Homocystinuria in the second quarter. We are continuing our patient identification activities and look forward to dosing the first patient once the clinical sites are able to begin screening patients.Recent Highlights and Updates Pegzilarginase in Arginase 1 Deficiency In May, Aeglea presented results from its 56 week analysis from the Companys completed Phase 12 clinical trial and ongoing open-label extension study during a late-breaking oral presentation at the 6th Congress of the European Academy of Neurology. Key results include: Treatment with pegzilarginase resulted in a significant reduction in plasma arginine from baseline with all 13 patients achieving plasma arginine levels within the target range 200 μM. 85 11 of 13 of patients were clinical responders based on mobility improvements evaluated using three assessments: 6MWT 6 Minute Walk Test, GMFM Gross Motor Function Part D standing and Part E walking, running, and jumping. Pegzilarginase was shown to have a favorable safety profile with more than 750 doses administered. To date, Aeglea has identified more than 240 Arginase 1 Deficiency patients. The number of identified patients represents more than 50 and 30 of the estimated genetic prevalence patient population in the U.S. and key European markets France, Germany, Spain, Italy and the United Kingdom, respectively.ACN00177 in Homocystinuria Aeglea initiated its Phase 12 clinical trial for ACN00177, a novel engineered human enzyme therapy designed to treat Homocystinuria, a serious metabolic disorder characterized by elevated plasma homocysteine which leads to a wide range of life-altering complications and reduced life expectancy.Corporate Eric Bradford, M.D., M.Sc., M.B.A. has been promoted to Chief Development Officer. Dr. Bradford will oversee the clinical programs for pegzilarginase and ACN00177 as well as shape the clinical development strategy for future programs from the Companys platform of novel human enzymes. Chief Medical Officer Ravi M. Rao, M.B BChir, Ph.D., will depart the company to pursue other opportunities. Dr. Rao will continue to support Aeglea in a medical advisor role through a transitional period.Ravi has been a valued and impactful member of the Aeglea team. While we are disappointed by his planned departure, we wish him the best as he returns to his roots in immunology research and development, said Dr. Quinn. I look forward to working more closely with Eric as we continue to strengthen our capabilities and advance pegzilarginase towards potential approval and launch.Upcoming Events Aeglea will be attending the following virtual investor conferences in the coming quarter. Wells Fargo Securities Healthcare Conference, September 9-10 H.C. Wainwright Healthcare Conference, September 13-15 Cantor Fitzgerald Global Healthcare Conference, September 15-17Further, Aegleas leadership looks forward to participating in dialogue about the Companys enzyme therapeutics platform during the following industry events, with additional details to be announced. World Orphan Drug Congress USA 2020, August 24-26 Child Neurology Society Annual Meeting-International Child Neurology Congress 2020, October 19-23Second Quarter 2020 Financial Results As of June 30, 2020, Aeglea had available cash, cash equivalents, marketable securities and restricted cash of 159.2 million. Based on Aegleas current operating plans, management believes it has sufficient capital resources to fund anticipated operations through 2022.Research and development expenses totaled 16.9 million for the second quarter of 2020 and 14.8 million for the second quarter of 2019. The increase was primarily associated with investing in manufacturing and pre-commercial activities for Aegleas lead product candidate, pegzilarginase; ramp-up in manufacturing activities for ACN00177 in Homocystinuria; and personnel-related expenses offset by decreasing clinical development expenses as a result of completing a Phase 12 clinical trial in patients with Arginase 1 Deficiency and closing out cancer trials. General and administrative expenses totaled 4.7 million for the second quarter of 2020 and 3.8 million for the second quarter of 2019. This increase was primarily due to additional employee headcount, ramping up commercial capabilities, and additional facilities to support company growth.Net loss totaled 21.4 million and 18.0 million for the second quarter of 2020 and 2019, respectively, with non-cash stock compensation expense of 1.6 million and 1.2 million for the second quarter of 2020 and 2019, respectively.About Pegzilarginase in Arginase 1 DeficiencyPegzilarginase is an enhanced human arginase that enzymatically lowers levels of the amino acid arginine. Aeglea is developing pegzilarginase for the treatment of patients with Arginase 1 Deficiency ARG1-D, a rare debilitating, progressive disease presenting in childhood with persistent hyperargininemia, spasticity, developmental delay, intellectual disability, seizures and early mortality. Pegzilarginase is intended for use as an enzyme therapy to reduce elevated blood arginine levels in patients with ARG1-D. Aegleas Phase 12 and Phase 2 open-label extension data for pegzilarginase in patients with ARG1-D demonstrated clinical improvements and sustained lowering of plasma arginine. The Companys single, global pivotal Phase 3 PEACE trial is designed to assess the effects of treatment with pegzilarginase versus placebo over 24 weeks with a primary endpoint of plasma arginine reduction.About ACN00177 in Homocystinuria Aeglea is developing ACN00177 for the treatment of patients with cystathionine beta synthase CBS deficiency, also known as Classical Homocystinuria. Homocysteine accumulation plays a key role in multiple progressive and serious disease-related complications, including thromboembolic vascular events, skeletal abnormalities including severe osteoporosis, developmental delay, intellectual disability, lens dislocation and severe near-sightedness. ACN00177 has been designed as a novel recombinant human enzyme, which degrades the amino acid homocysteine and its related homocystine dimer. With this mechanism, ACN00177 is intended to lower the abnormally high blood levels of homocysteine in patients with Homocystinuria. Preclinical data demonstrated that ACN00177 improved important disease-related abnormalities and survival in a mouse model of Homocystinuria. The Company initiated a Phase 12 trial in the second quarter of 2020 and continues patient identification and administrative activities. The timing of first patient dosing in this Phase 12 trial will depend on determinations by individual sites as they adjust to impacts from COVID-19.About Aeglea BioTherapeutics Aeglea BioTherapeutics is a clinical-stage biotechnology company redefining the potential of human enzyme therapeutics to benefit people with rare and other high burden diseases. Aegleas lead product candidate, pegzilarginase, is in a pivotal Phase 3 trial for the treatment of Arginase 1 Deficiency and has received both Rare Pediatric Disease and Breakthrough Therapy Designation. The Company initiated a Phase 12 clinical trial of ACN00177 for the treatment of Homocystinuria in the second quarter of 2020. Aeglea has an active discovery platform, with the most advanced program for Cystinuria. For more information, please visit Safe Harbor Forward Looking Statements This press release contains forward-looking statements within the meaning of the safe harbor provisions of the U.S. Private Securities Litigation Reform Act of 1995. Forward-looking statements can be identified by words such as: anticipate, intend, plan, goal, seek, believe, project, estimate, expect, strategy, future, likely, may, should, will and similar references to future periods. These statements are subject to numerous risks and uncertainties that could cause actual results to differ materially from what we expect. 