Acer Therapeutics Inc. and its collaboration partner, RELIEF THERAPEUTICS Holding SA announced that the U.S. Food and Drug Administration (FDA) has accepted for filing the New Drug Application (NDA) for ACER-001 (sodium phenylbutyrate) for the treatment of patients with Urea Cycle Disorders (UCDs). The FDA has assigned a Prescription Drug User Fee Act (PDUFA) target action date of June 5, 2022. Acer's 505(b)(2) NDA is supported by results from two previously announced bioequivalence (BE) trials in which ACER-001 showed similar relative bioavailability for both phenylbutyrate (PBA) and phenylacetate (PAA), the active metabolite of sodium phenylbutyrate, compared to the reference listed drug, BUPHENYL(R) (sodium phenylbutyrate).