Rare Daily Staff

Aeglea Therapeutics said that the U.S. Food and Drug Administration has granted Breakthrough Therapy designation to the company’s lead investigational therapy pegzilarginase for the treatment of Arginase 1 Deficiency. 

Arginase 1 Deficiency (ARG1-D) is an autosomal recessive condition resulting from a mutation that leads to a deficiency in the enzyme arginase, which leads to the inability to breakdown the amino acid arginine and remove ammonia from the blood. Symptoms usually begin around one to three years of age and include delayed growth, developmental delays, balancing trouble, tight muscles, irritability, poor appetite, vomiting, weak muscle tone, breathing trouble, trouble regulating body temperature, small head size, and hyperactivity. It is a rare debilitating disease that can lead to severe progressive neurological abnormalities and early mortality.

“The emerging clinical data demonstrating favorable effects of pegzilarginase treatment on both plasma arginine levels and important disease manifestations has led to the FDA’s designation of pegzilarginase as a breakthrough therapy,” said Anthony Quinn, president and CEO of Aeglea. “Breakthrough Therapy designation provides a path to work closely with the FDA as we quickly advance this potentially transformative therapy for patients suffering from ARG1-D.”

Breakthrough Therapy Designation is granted by the FDA to expedite the development and review of new therapies to treat serious or life-threatening conditions.  The criteria for granting requires preliminary clinical evidence that demonstrates the therapy may have substantial improvement on at least one clinically significant endpoint over available therapy. 

For pegzilarginase, granting the designation was based on data from the phase 1/2 and ongoing phase 2 open-label extension clinical trials in patients with ARG1-D. This designation conveys all fast-track program features, as well as more intensive FDA guidance on an efficient drug development program, and eligibility for rolling review and priority review. Aeglea expects to continue discussions with the FDA on the pegzilarginase program and our next steps in the fourth quarter of 2019.

Aeglea is currently recruiting patients for its single, global pivotal phase 3 PEACE trial designed to assess the effects of treatment with pegzilarginase versus placebo over 24 weeks with a primary endpoint of plasma arginine reduction from baseline.

Aeglea also has two pipeline programs in IND-enabling studies for homocystinuria and cystinuria and an active discovery pipeline.

Photo: Anthony Quinn, president and CEO of Aeglea

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