FDA Finalizes Guidance on Cell and Gene Therapies

The US Food and Drug Administration has finalised guidance for cell and gene therapies that replaces potency testing with lifecycle potency assurance, a move expected to streamline clinical trials and reduce costs for developers. The new guidance, announced on November 2, 2026, will impact genome editing developers and those working on CRISPR-Cas therapies, which are being used to treat a range of diseases, including sickle cell anaemia and muscular dystrophy. The FDA expects sponsors to have qualified release assays before pivotal trials, a requirement that could potentially justify clinical holds for therapies lacking adequate potency assurance.

The new guidance is non-binding, but its impact will be significant for genome editing developers who must now demonstrate lifecycle potency assurance in their clinical trials. The FDA's shift away from traditional potency testing comes after years of discussion and debate among industry experts and regulators. In 2011, the agency had established a framework for potency testing, which has been subject to criticism from some developers who argued that it was overly burdensome and did not accurately reflect the complexities of modern cell therapies. The FDA's decision to adopt a risk-based approach reflects a growing recognition of the need for more efficient and effective regulatory frameworks in the rapidly evolving field of gene editing.

The new guidance is expected to be welcomed by genome editing developers, who will now have greater flexibility in their clinical trials. Syntax Bio Programs' announcement that it has successfully programmed stem cells towards pancreatic beta cells in just four days is seen as a potential application of the FDA's new approach. The company's achievement raises hopes for more rapid progress in the development of gene therapies for diabetes and other diseases. However, critics argue that the shift from potency testing to lifecycle potency assurance may lead to inconsistent quality control across trials.