FDA CRL - Acorda Therapeutics Inc.

The U.S. Food and Drug Administration (FDA) has issued a Complete Response Letter to Acer Therapeutics Inc. for its New Drug Application (NDA 214860) for sodium phenylbutyrate, submitted under section 505(b)(2) of the Federal Food, Drug, and Cosmetic Act. The agency determined that the application cannot be approved in its current form. A primary issue cited was that the Sharp Clinical Services, Inc. manufacturing facility was not ready for inspection, which is a prerequisite for approval. Additionally, the proposed prescribing information and carton/container labeling require significant revisions to address prior FDA communications, correct formatting errors, and ensure compliance with regulatory content and format guidelines, including submission in Structured Product Labeling (SPL) format. The proprietary name, Olpruva, was acceptable but needs to be resubmitted with the application’s response. Further requirements include a comprehensive safety update, as outlined in 21 CFR 314.50(d)(5)(vi)(b), detailing any significant changes in the drug’s safety profile, new clinical data, adverse events, trial discontinuations, and worldwide safety experience. The FDA also noted a nonclinical concern regarding statistically significant increases in testis weights in a chronic dog study of talc, for which no No-Observed-Adverse-Effect-Level (NOAEL) was established. Acer Therapeutics must provide additional information or potentially conduct a new 9-month dog study to clarify this finding. Acer Therapeutics Inc. is required to address these deficiencies, including notifying the FDA when the manufacturing facility is ready for inspection, submitting revised labeling, providing the detailed safety update, and resolving the nonclinical issue, with a complete response expected within one year.