FDA issues final guidance for cell and gene therapy potency standards

The U.S. Food and Drug Administration issued final guidance on Monday 02 November 2026 for manufacturers of cellular and gene therapy products. The guidance provided recommendations for a Potency Assurance Strategy and applied to treatments for serious and often life-threatening conditions.

The FDA said manufacturers should test and verify each batch before it reaches a patient. Each batch must meet a defined potency standard confirming that the product is biologically active in a way that matches its intended therapeutic effect.

The guidance replaced FDA's 2011 potency testing guidance for cellular and gene therapy products. It provided flexible, risk-based recommendations for integrating potency considerations throughout development and commercialization.

The FDA said this included early-phase investigational new drug submissions, biologics license application approval and continued post-market verification. The recommendations also covered controls for variability in raw materials and testing during manufacturing.

By law, manufacturers were expected to verify that their products worked as intended from the time of approval through post-approval monitoring. The guidance addressed specialized considerations for products with short shelf lives, viral vector gene therapies and patient-specific therapies.

Karim Mikhail, Director of the Center for Biologics Evaluation and Research, said patients receiving cellular and gene therapies often had serious or life-threatening conditions and deserved assurance that administered products would perform as intended. The agency said the guidance supported regulatory clarity, product quality and patient safety.