Rare Daily Staff

The U.S. Food and Drug Administration granted rare pediatric disease designation to the Aeglea BioTherapuetics lead product candidate, pegzilarginase, for the treatment of arginase 1 deficiency, a rare, debilitating urea cycle disorder.

Arginase 1 deficiency presents in childhood. A genetic mutation results in an enzyme deficiency with persistent hyperargininemia, severe progressive neurological abnormalities and early mortality. The condition causes elevated levels of arginine and ammonia in the blood, and leads to severe, progressive, neurological abnormalities and early mortality.

Pegzilarginase is an enhanced human arginase that enzymatically depletes the amino acid arginine. Pegzilarginase is intended for use as an enzyme replacement therapy in patients to reduce elevated blood arginine levels.

The company’s interim phase 1/2 data demonstrated clinical improvements and rapid and sustained lowering of plasma arginine in arginase 1 deficiency patients.

The FDA grants Rare Pediatric Disease designation for serious or life-threatening diseases with manifestations in individuals aged from birth to 18 years, including access to the FDA’s expedited review and approval process. The designation makes pegzilarginase eligible for a Rare Pediatric Disease Priority Review Voucher upon approval of the therapy by the FDA.

The vouchers can be used to reduce the time of an FDA new drug approval review to six months from ten months. The vouchers are potentially lucrative because they are transferable. Most recently, Ultragenyx and Kyowa Hakko Kirin sold their Priority Review Voucher for $80.6 million.

“This designation underscores the seriousness of Arginase 1 Deficiency and its devastating impact on patients and families living with this disease,” said Anthony Quinn, president and CEO of Aeglea. “We look forward to continued collaboration with the FDA as we advance pegzilarginase into a pivotal study in the first half of 2019.”


October 1, 2018
Photo: Anthony Quinn, president and CEO of Aeglea