FDA Finalizes Potency Assurance Guidance for Cell and Gene Therapies

FDA issued final guidance on November 2, 2026, recommending that manufacturers of cellular and gene therapy (CGT) products implement a science- and risk-based Potency Assurance Strategy across a product's lifecycle.¹ The guidance, Potency Assurance for Cellular and Gene Therapy Products, replaces the FDA's 2011 potency testing guidance for CGT products. It applies to treatments for serious and often life-threatening conditions.¹

"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, BPharm, MS, director of the Center for Biologics Evaluation and Research (CBER) at FDA, in an agency press release.¹

What does the final guidance recommend?

Under the Potency Assurance Strategy, manufacturers are guided to test and verify, before a product reaches a patient, that every batch meets a defined potency standard for its intended therapeutic effect.¹ By law, manufacturers must verify that their products work as intended from approval through postapproval monitoring. The guidance presents FDA's current thinking on how to meet that requirement.¹

The recommendations are flexible and risk-based. They are intended to integrate potency considerations at every stage, from early-phase investigational new drug (IND) submissions through biologics license application (BLA) approval and continued postmarket verification.¹ Key topics include controls for variability in raw materials, testing during manufacturing, and laboratory tests that confirm each batch is biologically active in a way that matches its intended therapeutic effect.¹

The guidance also addresses specialized considerations for products with short shelf lives, viral vector gene therapies, and patient-specific therapies.¹ FDA also plans to host a webinar on December 10, 2026, to help stakeholders understand and implement the guidance.¹

How did the guidance develop?

FDA issued the guidance in draft form in December 2023 under docket FDA-2023-D-4299.² The draft described a risk-based approach to assuring potency throughout the product lifecycle. That approach included progressive potency strategies for investigational products and lot-release testing for licensed products. The draft also stated that the final version would supersede the January 2011 guidance, Potency Tests for Cellular and Gene Therapy Products.²

How does it relate to other recent CGT guidance?

The potency guidance follows other recent FDA actions on individualized CGT products. On October 27, 2026, the agency issued the draft guidance, Individualized Human Genome Editing Products: Considerations for BLA Submission and Postapproval Management. The draft outlines how sponsors can structure a single BLA for genome editing products tailored to each patient's genetic variant.³ It introduced the Individualized Feature Space (IFS), a set of predefined boundaries within which new patient-specific variants could be added to an approved BLA using in vitro data rather than new clinical trials.³ Comments on that draft are due by November 27, 2026.³

Both documents address products made for individual patients. The potency guidance includes specialized considerations for patient-specific therapies. The genome editing draft relies on assays showing adequate safety and activity for each new variant within the IFS.¹^,³

What are the limitations?

FDA guidance documents represent the agency's current thinking and are not legally binding. How the FDA applies the flexible, risk-based recommendations will depend on the product and may be clarified further through the December webinar and individual sponsor interactions. The announcement did not detail which recommendations changed from the 2023 draft, and the genome editing guidance remains in draft form.

References

1. FDA. FDA provides clarity to support cell and gene therapy development and quality. Press release. Published November 2, 2026. Accessed November 3, 2026. https://www.fda.gov/news-events/press-announcements/fda-provides-clarity-support-cell-and-gene-therapy-development-and-quality
2. FDA. Potency assurance for cellular and gene therapy products; draft guidance for industry; availability. Fed Regist. 2023;88(248):89707-89709. Published December 28, 2023. Accessed November 3, 2026. https://www.govinfo.gov/content/pkg/FR-2023-12-28/html/2023-28596.htm
3. US Department of Health and Human Services. FDA and CMS announce new steps to advance gene therapies and expand access for patients with rare diseases. Press release. Published October 27, 2026. Accessed November 3, 2026. https://www.hhs.gov/press-room/fda-cms-advance-gene-therapies-rare-diseases-patient-access.html