TL;DR
The FDA issued final guidance recommending that cell and gene therapy manufacturers use a science- and risk-based Potency Assurance Strategy throughout a product’s lifecycle. It replaces the agency’s 2011 potency-testing guidance and covers testing, manufacturing controls and continued verification after approval.
The U.S. Food and Drug Administration issued final guidance on November 2, 2026, recommending that cell and gene therapy manufacturers build a Potency Assurance Strategy into development, manufacturing and post-approval monitoring. The guidance replaces the FDA’s 2011 recommendations on potency testing and sets out the agency’s current thinking on how manufacturers can verify that therapies meet defined standards for their intended biological activity.
The guidance applies to cellular and gene therapy products, including treatments for serious and often life-threatening conditions. The FDA says manufacturers are expected by law to verify that their products work as intended, from approval through post-approval monitoring. Its recommendations describe a broader approach to potency assurance rather than relying only on a single test at one point in development.
Under the FDA’s proposed framework, manufacturers should consider potency throughout the product lifecycle, from early-phase investigational new drug submissions through biologics license application review and continued verification after a product reaches the market. The guidance discusses managing variability in raw materials, testing during manufacturing and laboratory tests intended to show that each batch is biologically active in a way consistent with its intended therapeutic effect.
The recommendations also address issues for products with short shelf lives, viral-vector gene therapies and patient-specific therapies. The FDA characterizes its approach as flexible and risk-based, meaning the strategy should account for the particular product and its manufacturing process. The agency has not described the guidance as a new law; it presents recommendations on meeting existing requirements.
Potency Checks Across Therapy Lifecycles
Potency assurance matters because cell and gene therapies can be complex to produce, and some are made for an individual patient. A manufacturer needs a way to establish that each batch has the biological activity tied to its intended therapeutic effect. The FDA says the guidance is meant to help companies plan that verification across development and production, rather than treat potency as an isolated testing issue.
For patients, the underlying concern is whether a therapy administered to them performs as intended. The agency links its recommendations to product quality and patient safety, while also saying clearer expectations can support innovation and access. Those are the FDA’s stated aims; the announcement does not provide data showing that the guidance will shorten development timelines or increase patient access.
For manufacturers, the guidance offers a common regulatory reference as products move from early clinical development toward licensing and commercial supply. Its attention to raw-material variability, product-specific testing and post-market checks may inform how companies design controls and document potency. The practical effect will depend on how firms apply the recommendations to different therapies and how the FDA evaluates those plans.
Replacing the 2011 Testing Guidance
The final document replaces FDA guidance on potency testing for cell and gene therapy products issued in 2011. The agency describes the new document as its current thinking on how manufacturers can meet the requirement to verify product performance. It frames potency as an assurance strategy spanning the product lifecycle, including post-approval verification, rather than focusing solely on a test result.
That scope reflects the range of products covered. Some therapies use viral vectors; others involve cells prepared for a particular patient, and some products have limited shelf lives. The FDA’s announcement identifies these as areas needing specialized consideration, but does not set out one universal assay or testing protocol for every product. The recommendations are intended to be applied with attention to each therapy’s characteristics and risks.
FDA Center for Biologics Evaluation and Research Director Karim Mikhail said patients receiving these therapies often have serious or life-threatening conditions, including cancers and rare diseases. He described the guidance as part of an effort to match innovation with high standards for quality and patient safety.
“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.”
— Karim Mikhail, director of the FDA’s Center for Biologics Evaluation and Research
How Manufacturers Will Apply Recommendations
The announcement does not specify how individual manufacturers should design a potency assay for each therapy, nor does it provide a single testing method that applies across all products. The guidance’s risk-based approach means implementation will depend on product characteristics and manufacturing processes. The FDA release also does not quantify likely effects on development costs, review times, approvals or patient access.
It is also not clear from the announcement how the agency will assess particular company strategies in future applications or what additional evidence may be requested for specific products. Those questions may be addressed through the full guidance and subsequent regulatory interactions. The FDA’s release confirms that the document is final, but its recommendations should not be mistaken for a report of newly approved therapies or a change to the legal requirement described by the agency.
FDA Webinar Set for December
The FDA says it will hold a webinar on December 10, 2026, to help stakeholders understand and implement the final guidance. The announcement does not give further details about the webinar’s format or registration. Manufacturers and other interested stakeholders can consult the agency’s guidance materials for the recommendations themselves and watch for additional FDA information about the session.
As companies apply the framework to development and manufacturing programs, its practical effects will become clearer through regulatory submissions and post-approval monitoring. The agency’s announcement does not identify a further deadline or a separate implementation timetable.
Key Questions
What did the FDA announce?
The FDA issued final recommendations for a Potency Assurance Strategy for cell and gene therapy products, covering development, manufacturing and post-approval monitoring.
Does the guidance replace an earlier FDA document?
Yes. It replaces the FDA’s 2011 potency-testing guidance for cell and gene therapy products.
What does potency assurance cover?
The recommendations address how manufacturers can verify that products meet defined standards for intended biological activity. Topics include raw-material variability, manufacturing tests and laboratory testing of batches.
Does the guidance require one specific test for every therapy?
The FDA describes its recommendations as flexible and risk-based and highlights different product types requiring specialized consideration. Its announcement does not prescribe one universal test for all therapies.
When will the FDA discuss the guidance with stakeholders?
The agency says it will host a webinar on December 10, 2026, to help stakeholders understand and implement the guidance.
Source: fda.gov
