The U.S. Food and Drug Administration today issued final guidance for manufacturers of cellular and gene therapy products to implement a comprehensive, science- and risk-based plan for making sure their products meet potency standards. The guidance applies to treatments for serious and often life-threatening conditions, according to the agency.

The document provides the FDA’s recommendations for a Potency Assurance Strategy. That strategy guides manufacturers to test and verify, before a product reaches a patient, that every batch meets a defined standard of potency to do what the product is supposed to do therapeutically. The final guidance, titled Potency Assurance for Cellular and Gene Therapy Products, replaces the FDA’s 2011 potency testing guidance for cellular and gene therapy products.

By law, manufacturers are expected to verify that their products work as intended, from the time of approval through post-approval monitoring. The agency said the final guidance provides its current thinking and recommendations on how manufacturers can meet that requirement.

“Patients who receive cellular and gene therapies are often battling serious or life-threatening conditions, such as cancers and rare diseases, and they deserve the assurance that the product administered to them will perform as intended,” said Karim Mikhail, B. Pharm., M.S., Director of the Center for Biologics Evaluation and Research. “This guidance reflects the FDA’s commitment to ensuring America remains the best place in the world to innovate — and that innovation is matched by the highest standards of product quality and patient safety,” Mikhail said.

The guidance provides flexible, risk-based recommendations for manufacturers on how to integrate potency considerations at every stage of development and commercialization, the agency said. Those stages run from early-phase investigational new drug submissions through biologics license application approval and continued post-market verification. Key topics include controls for variability in raw materials, testing during manufacturing, and lab tests that confirm each batch is biologically active in a way that matches its intended therapeutic effect.

The guidance also addresses specialized considerations for products with short shelf lives, viral vector gene therapies, and patient-specific therapies. The FDA said that by giving manufacturers a clear, predictable roadmap, the guidance supports faster access to safe and effective therapies for patients who often have no other treatment options, many of whom receive products made individually for a single person.

In doing so, the agency said, the guidance advances its public health pillars: protecting patients through rigorous quality standards, promoting innovation by providing regulatory clarity, and reinforcing the integrity of the supply chain for some of the most complex medical products in existence.

The FDA will host a webinar on Dec. 10, 2026, to help stakeholders understand and implement the guidance.