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# Guide on Using Prior Knowledge for Genome Editing Gene Therapies
- URL: https://www.fdaweb.com/guide-on-using-prior-knowledge-for-genome-editing-gene-therapies/
- Published: 2026-06-02T12:00:00.000Z
- Updated: 2026-09-14T13:40:21.000Z
- Author: David McFarland
- Tags: Drugs, #legacy-id-D5161242

FDA has released a draft guidance outlining how developers of genome-editing gene therapies can leverage existing scientific and manufacturing knowledge to streamline product development and regulatory review. The draft was issued as part of the current user fee agreement to provide recommendations on leveraging prior knowledge in cell and gene therapy development.

The [document](https://www.fda.gov/media/192810/download?ref=fdaweb.com), *Leveraging Prior Knowledge in the Development of Human Gene Therapy Products Incorporating Genome Editing*, provides recommendations for manufacturers seeking to use previously generated data and experience to support the development of both in vivo and ex vivo genome-editing therapies.

The document is intended to help sponsors determine when it may be scientifically appropriate to rely on "prior knowledge" — including publicly available scientific information and experience gained through established technology platforms — in lieu of generating certain new data. The agency says such approaches could improve review efficiency and accelerate development timelines, particularly for rare disease therapies where patient populations are limited and unmet medical needs are significant.

FDA defines "prior knowledge" as either publicly available scientific information that is broadly accepted by experts or "platform knowledge" derived from experience developing and manufacturing similar products and technologies. Examples include published scientific literature, regulatory guidance documents, manufacturing data from previous products, information contained in master files maintained by contract development and manufacturing organizations, and data generated through industry collaborations and consortiums.

The agency notes that platform knowledge may come from a company's own development programs, third-party manufacturers, suppliers, or publicly available scientific resources. Sponsors may also seek to reference proprietary information submitted to FDA through master files, provided they obtain authorization from the owner of the data.

The guidance emphasizes that the appropriateness of leveraging prior knowledge depends on the specific context. For chemistry, manufacturing and controls (CMC) information, FDA said the relevance of prior data may depend on similarities in product structure, manufacturing processes, facilities, and equipment. For nonclinical studies, considerations include similarities in genomic edits, cell sources, formulations, mechanisms of action, and manufacturing methods.

Clinical data may also be leveraged under certain circumstances, according to the agency, but FDA says sponsors should evaluate factors such as similarities between products, diseases being treated, clinical development stages, and the intended use of the data.

FDA highlights that some types of knowledge may be easier to leverage than others. For example, information related to analytical methods may be more broadly applicable across products than data tied directly to product-specific characteristics such as potency or biological activity.

The agency also stresses that sponsors seeking to rely on prior knowledge should provide a scientific justification demonstrating why the information is applicable to the product under development. FDA also encourages developers to discuss proposed leveraging strategies with the agency during development.

Although the guidance focuses on genome-editing therapies, FDA notes that some recommendations may also be relevant to other cell and gene therapy platforms, including adeno-associated virus (AAV)-based therapies, nanoparticle-delivered gene therapies, and ex vivo modified cell therapies that do not incorporate genome editing.

For sponsors developing genome editing therapies, FDA says the draft “complements the agency's [Plausible Mechanism Framework](https://www.fda.gov/news-events/press-announcements/fda-launches-framework-accelerating-development-individualized-therapies-ultra-rare-diseases?ref=fdaweb.com), providing the scientific tools and data-sharing strategies that allow sponsors to efficiently establish the evidentiary foundation this approach requires. It also works in tandem with the FDA's recently issued draft guidance, [*Safety Assessment of Genome Editing in Human Gene Therapy Products Using Next-Generation Sequencing*](https://www.fda.gov/news-events/press-announcements/fda-issues-draft-guidance-genome-editing-safety-standards-advance-gene-therapy-development?ref=fdaweb.com), which recommends methods for evaluating off-target editing risks.”