FDA Refuses to File Aeglea Biologics License Application
The Biotech Firm Aeglea received a refusal to file from the FDA for its biologic pegzilarginase used to treat rare diseases.
Aeglea BioTherapuetics announced that it had failed to secure a biologics license application (BLA) from the FDA after administrators issued a refusal to file for the company’s biologic pegzilarginase.
The FDA returned Aeglea’s application requesting more information to prove the effectiveness of pegzilarginase in the treatment of arginase-1 deficiency (ARG1-D).
In the PEACE phase 3 clinical trial, pegzilarginase reached a 76.7% plasma arginine reduction, accompanied by a positive trend in motor function measures. The FDA’s choice to return the application was based on the level of motor function improvement in treated patients. To reach the market with their biologic, Aeglea will need to convey the advantage of reducing plasma arginine in ARG1-D affected people.
ARG1-D is a rare disease that affects children and can lead to severe disorders if left untreated. The condition is passed through hereditary genetics, and it affects anywhere from 1 in 300,000 and 1 in 1,000,000 births. Recessive genetic diseases like ARG1-D occur when both parents possess the same recessive gene for the disease.
"We believe the requests identified in the refusal to file (RTF) letter related to CMC can be readily addressed, and we intend to work collaboratively with the FDA to identify a viable path forward to demonstrate that lowering plasma arginine confers a clinical benefit," said Anthony G. Quinn, PhD, president, and chief executive officer of Aeglea. "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."
Biologics like pegzilarginase are specialty drugs that target specific diseases. Often, these drugs end up being the only treatment for a particular illness, as is the case for ARG1-D. The use of biologics is expected to grow exponentially in the near future.
FDA RTFs are generally rare, and less than 5% of applications are rejected with this method, while most other rejections come as complete response letters. The RTF indicates that the FDA is awaiting important additional data, and the administration had halted the evaluation process before reviewing the entire market application.
Recovering from the aftermath of an RTF can be a quick process for well-equipped pharmaceutical companies. For instance, in May of 2020, Bristol Myers Squibb received an RTF for its CAR T cell immunotherapy — idecabtagene vicleucel — and less than one year later, the company received FDA approval for the same drug.
