Aeglea BioTherapeutics Shares Plummet Following Refusal To File Letter From FDA

Aeglea BioTherapeutics, Inc. (NASDAQ: AGLE) announced the U.S. Food and Drug Administration (FDA) has refused to accept the company’s Biologics License Application (BLA) with a Refusal to File (RTF) letter.

The company filed the BLA in April for its lead drug candidate pegzilarginase for the treatment of Arginase 1 Deficiency (ARG1-D), based on positive results from PEACE Phase 3 study as well as a Phase 1/2 clinical trial and its open-label extension study.

Arginase 1 Deficiency is a rare, progressive and debilitating disease characterized by high levels of arginine.

The FDA communicated in the RTF letter, requesting additional data to support effectiveness, such as evidence showing that plasma arginine and metabolite reduction predicts clinical benefit in patients with ARG1-D.

Anthony Quinn, president and chief executive officer, commented : “While we are disappointed in the outcome of the FDA's initial review of our BLA, we continue to believe in the potential of pegzilarginase and thank the FDA for their constructive comments and ongoing collaboration.”

Shares of Aeglea BioTherapeutics are trading down 33% at $1.01 in the regular market session.