The U.S. Food and Drug Administration (FDA) has issued final guidance outlining how manufacturers of cell and gene therapies can establish and maintain product potency throughout development, manufacturing and commercialization. The recommendations call for a science- and risk-based approach that builds potency assurance into every stage of a therapy’s lifecycle, helping ensure products consistently deliver their intended therapeutic effects.

The document, Potency Assurance for Cellular and Gene Therapy Products, replaces the agency’s 2011 guidance on potency testing for these products. It applies to therapies being developed for serious and often life-threatening conditions, including cancers and rare diseases. The FDA says manufacturers are responsible for demonstrating that their products work as intended, from initial approval through post-market monitoring.

The guidance introduces recommendations for a comprehensive Potency Assurance Strategy, which is intended to help manufacturers establish appropriate controls and testing procedures before products are administered to patients. Rather than relying on a single potency test, the FDA recommends integrating potency considerations throughout development and production, from early investigational new drug (IND) submissions through biologics license application (BLA) approval and continued commercial oversight.

Key areas addressed include managing variability in raw materials, implementing in-process manufacturing controls and using laboratory assays to confirm that each batch demonstrates biological activity consistent with its intended mechanism and therapeutic effect. The recommendations also address challenges associated with products that have short shelf lives, viral vector-based gene therapies and patient-specific treatments.

The agency emphasizes that potency assurance is particularly important for cell and gene therapies because many are developed for patients with limited treatment options, and some products are manufactured individually for a specific patient. FDA officials said the guidance is intended to provide manufacturers with greater regulatory clarity while maintaining expectations for product quality and patient safety.

The FDA will hold a webinar on December 10, 2026, to discuss the final guidance and help stakeholders understand its recommendations and implementation.

Visit www.FDA.gov for more information.