US FDA invites consultation on its draft guidance for genome editing therapies to standardise regulatory approval process

Draft guidance from regulator sets out next-generation sequencing standards to assess genome editing safety and support faster development of gene therapies

The US Food and Drug Administration (FDA) has issued draft guidance to support sponsors that seek approval for human gene therapy products that incorporate genome editing technologies, with a focus on standardised approaches to safety evaluation. The agency has stated that – once finalised – the document will set out scientifically grounded recommendations to enable comprehensive assessment of potential risks, with the intention to accelerate patient access to effective therapies.

The draft guidance has centred on the application of next-generation sequencing methodologies to detect and quantify unintended genomic alterations. These include off-target editing events and broader disruptions to genome integrity, both of which remain central safety concerns in the clinical development of gene editing interventions.

By establishing clearer expectations for sequencing strategies, analytical thresholds and reporting frameworks, the agency has sought to reduce variability in how developers generate and interpret safety data.

“Genome editing holds extraordinary promise for treating previously incurable genetic diseases and today’s announcement represents the FDA’s forward approach to drive innovation and advance the development of genome editing therapies,” said Dr. Marty Makary, who leads the agency.

“This guidance provides sponsors with clear, scientifically-grounded recommendations for evaluating off-target editing risks using state-of-the-art sequencing technologies. We are serious about moving this ball forward,” he added.

The guidance, issued through the Center for Biologics Evaluation and Research (CBER), has aligned with a broader regulatory framework introduced earlier in 2026 to support the development of individualised therapies for ultra-rare diseases. That framework has aimed to reshape engagement between regulators and developers, particularly in cases where conventional large-scale clinical trials are not practical. In this context, robust preclinical safety characterisation has taken on increased importance as a foundation for regulatory decision-making.

Titled: ‘Safety Assessment of Genome Editing in Human Gene Therapy Products Using Next-Generation Sequencing’, the document provides detailed technical recommendations that extend earlier guidance issued in January 2024. The current draft has placed particular emphasis on next-generation sequencing-based approaches to evaluate unintended genomic modifications, including both small-scale sequence changes and larger chromosomal rearrangements.

The recommendations have applied to nonclinical studies that support investigational new drug applications and biologics licence applications, and have covered both ex vivo approaches, in which cells undergo modification outside the body, and in vivo strategies, where editing occurs directly within patient tissues.

“Next-generation sequencing not only detects off-target editing and assesses chromosomal integrity; it also requires science-based recommendations for its use. We’re giving sponsors a roadmap for comprehensive safety assessment while supporting the efficient development of these promising therapies,” said Dr. Vinay Prasad, chief medical and scientific officer and director of the CBER.

“Our goal is to work collaboratively with the scientific community to bring safe and effective genome editing therapies to patients who need them most,” he said.

The FDA has also reiterated the importance of early regulatory engagement. Sponsors have been encouraged to initiate dialogue at an early stage in development, including prior to investigational new drug submission, through mechanisms such as Initial Targeted Engagement for Regulatory Advice on CBER/Center for Drug Evaluation and Research Products and pre-investigational new drug meetings. Such interactions have aimed to clarify expectations, align study design with regulatory standards and reduce the risk of later-stage delays.

The draft guidance has been released for public consultation, with stakeholders invited to submit comments by July 14, 2026 in the US Federal Register via Regulations.gov. The agency has stated that it will review all submissions before it proceeds to finalise the recommendations.