The US Food and Drug Administration (FDA) has issued final guidance for manufacturers of Cellular and Gene Therapy (CGT) products, outlining recommendations for implementing a comprehensive, science- and risk-based Potency Assurance Strategy to ensure products consistently meet established potency standards.

Titled Potency Assurance for Cellular and Gene Therapy Products, the guidance provides recommendations on how manufacturers can establish, evaluate and maintain product potency throughout the development and commercialisation process. It aims to ensure that every batch meets predefined potency requirements and delivers its intended therapeutic effect before being administered to patients.

The final guidance replaces the FDA's 2011 guidance on potency testing for cellular and gene therapy products. It applies to therapies developed for serious and often life-threatening conditions, including cancers and rare diseases. Under existing regulatory requirements, manufacturers must demonstrate that their products perform as intended, both at the time of approval and through post-approval monitoring.

Commenting on the guidance, Karim Mikhail, Director of the Centre for Biologics Evaluation and Research (CBER), said that patients receiving cellular and gene therapies often face serious or life-threatening conditions and require assurance that the products administered to them will perform as intended. He added that the guidance reflects the FDA's commitment to supporting innovation while maintaining high standards of product quality and patient safety.

The guidance provides flexible, risk-based recommendations for integrating potency considerations at every stage of product development and commercialisation. These extend from early-phase Investigational New Drug (IND) submissions through Biologics License Application (BLA) approval and continued post-market verification.

Key areas covered include managing variability in raw materials, implementing appropriate testing during manufacturing and using laboratory assays to confirm that each batch demonstrates the biological activity associated with its intended therapeutic effect.

It also addresses specific considerations for products with short shelf lives, viral vector-based gene therapies and patient-specific treatments. These recommendations are intended to help manufacturers establish appropriate potency controls for complex products while accounting for differences in their manufacturing processes and therapeutic characteristics.

According to the FDA, the guidance provides manufacturers with a clearer regulatory framework for demonstrating product potency and maintaining consistent quality. It is also intended to support the development and availability of safe and effective therapies, particularly for patients with limited treatment options and those receiving individually manufactured products.

The FDA will host a webinar on December 10, 2026, to help stakeholders understand the recommendations and their implementation.

The FDA operates under the US Department of Health and Human Services and is responsible for protecting public health by ensuring the safety, effectiveness and security of human and veterinary drugs, vaccines, biological products and medical devices, among other regulated product.