FDA Draft Guidance Sets Out How Genome Editing Developers Can Reuse Prior Knowledge

The US Food and Drug Administration on June 2 published a draft guidance describing how developers of gene therapies that use genome editing can draw on existing scientific and platform data to speed development, rather than generating every data set anew for each product. The document, "Leveraging Prior Knowledge in the Development of Human Gene Therapy Products Incorporating Genome Editing," was issued by the Center for Biologics Evaluation and Research's Office of Therapeutic Products, according to the FDA guidance page.

The draft applies to gene therapy products incorporating ex vivo and in vivo genome editing of human somatic cells. FDA says it reflects the agency's current thinking on the type of prior knowledge, meaning public and platform knowledge, that may be scientifically appropriate to leverage, and how sponsors may use it "to increase review efficiency and accelerate product development across multiple programs."

Manufacturing, nonclinical and clinical data

The recommendations cover chemistry, manufacturing and controls (CMC), nonclinical and clinical prior knowledge. On the guidance page, FDA writes that "The ability to leverage prior knowledge to expedite product development may be particularly helpful in the context of GE products intended to treat rare diseases, many of which may be serious and life threatening."

As reported by Regulatory Focus, the news service of the Regulatory Affairs Professionals Society, the CMC examples address analytical methods, method qualification and validation data, as well as lot release specifications, stability, comparability, process characterization and validation, and data from manufacturing facilities. For nonclinical work, how much prior knowledge can be leveraged may depend on similarity in on-target genomic edits, cell sources, manufacturing processes, formulation and intended therapeutic mechanism; for in vivo products, route of administration, dosing regimens and dose levels also matter.

FDA set a condition on all such reuse. "However, in all cases, when leveraging any kind of prior knowledge, a sponsor should provide a justification for the applicability of the data being leveraged," the agency said, according to Regulatory Focus. It added that "Sponsors should submit any leveraging proposals to FDA for consideration, and, if desired, discussion (see section IV)."

A user-fee commitment with wider reach

The agency tied the document to its drug user-fee agreement. "This guidance is being released as part of a [Prescription Drug User Fee Amendments (PDUFA VII)] commitment to publish guidance on leveraging prior knowledge for cell and GT (CGT) products," FDA said, as quoted by Regulatory Focus. FDA added that, while the draft focuses on genome editing products, some recommendations may apply to other cell and gene therapies, including adeno-associated viral (AAV) vectors, nanoparticle-based products and ex vivo-modified cell therapies that do not use genome editing, though additional considerations may apply to those product types.

The draft is not for implementation and contains non-binding recommendations. FDA is accepting comments under docket number FDA-2026-D-1257.