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# Breakthrough Status for Arginase 1 Deficiency Candidate
- URL: https://www.fdaweb.com/breakthrough-status-for-arginase-1-deficiency-candidate/
- Published: 2019-07-26T12:00:00.000Z
- Updated: 2026-09-15T01:40:23.000Z
- Author: David McFarland
- Tags: Drugs, #legacy-id-D5144630

FDA has granted Aeglea BioTherapeutics a breakthrough therapy designation for pegzilarginase, indicated for treating Arginase 1 Deficiency, a rare progressive disease presenting in early childhood that results in severe complications and early mortality. The designation is based on data from a Phase 1/2 and ongoing Phase 2 open-label extension clinical trials that demonstrated favorable effects of pegzilarginase treatment on both plasma arginine levels and important disease manifestations, according to the company.

Pegzilarginase is described by Aeglea as an enhanced human arginase that enzymatically depletes the amino acid arginine. It is intended for use as an enzyme replacement therapy in patients to reduce elevated blood arginine levels. The company is currently recruiting patients for its single, global pivotal Phase 3 PEACE trial designed to assess the drug's effects versus placebo over 24 weeks with a primary endpoint of plasma arginine reduction from baseline.