FDA slaps CRL on Acer Therapeutics' NDA for ACER-001

The US Food and Drug Administration (FDA) has issued a Complete Response Letter (CRL) regarding the New Drug Application (NDA) for ACER-001 (sodium phenylbutyrate) for oral suspension for the treatment of patients with urea cycle disorders (UCDs), submitted by US rare diseases drug developer Acer Therapeutics (Nasdaq: ACER) and its collaboration partner, Relief Therapeutics Holdings (SIX: RLF).

The news pushed Acer’s shares 12% lower to $1.55 in early trading, while Relief’s shares were down 7.1% at 0.025 Swiss francs by mid-afternoon.

The CRL indicates that the FDA cannot approve the NDA in its current form. The CRL states: “[The FDA’s] field investigator could not complete inspection of [Acer’s third-party contract packaging manufacturer], because the facility was not ready for inspection. Satisfactory inspection is required before [the NDA] may be approved. Please notify us in writing when this facility is ready for inspection.”