On April 14, 2026, the United States Food and Drug Administration (“FDA”) issued a draft guidance for sponsors seeking approval of human gene-editing therapy products involving gene-editing technologies. The guidance provides recommendations for assessing the safety of genome-editing therapies to bring effective treatments to patients.
The guidance includes considerations for next generation sequencing (“NGS”), on-target edit site assessment, studies assessing off-target editing activity, off-target edit site analysis accounting for human genetic variation, NGS method-based chromosomal integrity analysis, and submission of study reports describing off-target editing and chromosomal translocation analyses to the FDA. See Guidance at i. A central theme in the guidance is the goal of evaluating and mitigating off-target editing—a mechanism through which unintended, potentially harmful edits may occur in other parts of the genome as a consequence of a gene-editing therapy.
The FDA stated that this guidance may “guide stakeholders on designing nonclinical studies that use NGS methods and bioinformatics to evaluate the potential safety risks associated with off-target editing and loss of genome integrity in human [genome editing] products submitted in support of Investigational New Drug (IND) applications and Biologics License Applications (BLAs).” Id. at 1. Additionally, the draft guidance offers recommendations for both ex vivo products, where cells are edited outside of the body, as well as in vivo products, where gene editing occurs within the patient’s body. Id. at 6–7.
The draft guidance complements the FDA’s previous guidance from January 2024, titled “Guidance for Industry: Human Gene Therapy Products Incorporating Human Genome Editing.” According to FDA Commissioner Marty Makary, M.D., M.P.H., “[g]enome editing holds extraordinary promise for treating previously incurable genetic diseases,” and the draft guidance “represents the FDA’s forward approach to drive innovation and advance the development of genome editing therapies.”
The draft guidance is now available for public comment. Comments must be submitted by July 14, 2026.
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