When the United States (US) Food and Drug Administration (FDA) releases a new guidance, there can either be little fanfare, or a fervor that spreads across the drug development industry causing a great deal of chatter throughout the Biotech and Pharmaceutical landscape. 

On June 2, 2026, the FDA issued a new draft Guidance for Industry entitled “Leveraging Prior Knowledge in the Development of Human Gene Therapy Products Incorporating Genome Editing; Draft Guidance for Industry (June 20926).” The chatter began in a big way. 

The emails started flowing. Cell phones lit up with texts asking if everyone saw the latest release. What was released was more than just the usual guidance, rather it was the real-time dawning of a new era for cell and gene therapies rife with possibilities and full of hope both for drug developers and for patients. This was officially an introduction to what was previously thought of as a “Neverland.”

What the Agency Actually Stated

The guidance signaled to the industry that cell and gene therapy developers may rely on prior knowledge, inclusive of both publicly available information and product platform knowledge, to support portions of regulatory submissions rather than regenerating all of the data from scratch, essentially. This prior knowledge may affect Chemistry, Manufacturing, and Controls (CMC), the nonclinical data package, and/or the clinical sections of an Investigational New Drug (IND) application or potentially later submissions, provided the Sponsor company provides a strong scientific justification for why the prior data is applicable to the new investigational product. 

The regulatory burden shifts from “generate everything anew” to “demonstrate scientific relevance and comparability.” In other words, a Sponsor must clearly explain, in detail, why the prior knowledge is transferable based on factors such as molecular similarity, manufacturing process similarity, formulation, route of administration (RoA), dose justification, intended mechanism of action (MoA), and the nature of a genomic edit.

Early FDA Engagement and Discussion Now Even More Important

The Industry and Regulators must be on the same path walking in lock-step together for this development pathway to work. The guidance encourages Sponsor companies to bring possible leveraging strategies and bridging rationale to the Agency for discussion early, well before IND submission, so the Agency can assess whether the proposed reliance on prior knowledge is scientifically sound. From a regulatory strategy standpoint, that means early meetings such as “INitial Targeted Engagement for Regulatory Advice on CBER/CDER ProducTs” (INTERACT) meetings and pre-IND meetings will be more important than ever before. Receiving regulatory alignment and a clear path forward could bring new, cutting-edge therapies to patients earlier than industry would have previously thought possible.  

CMC Strategy Benefit

Every Sponsor company engaged in cell and gene therapy (CGT) development is well aware of the time drain and cost burden involved in the CMC components of any new therapy.  CMC is usually on the critical path for an IND or for marketing approval. A major implication of the issued guidance is that CMC may increasingly be reviewed through a platform lens. 

For example, if a Sponsor uses the same editing system, similar manufacturing workflow, analytical methods, release testing, stability approaches, or process controls across programs, the guidance suggests some of that knowledge may be leveraged across therapies and applications. This could shorten development timelines when comparability is convincingly established. The shortened development time inevitably leads to cost savings for the Sponsor company but will eventually lead to decreased costs for patients and payers. In any industry, time is money and cost of goods is impactful.  

Nonclinical Programs 

For genome editing products, nonclinical expectations may become more streamlined. Instead of repeating every toxicology or proof-of-concept (POC) study, Sponsors may be able to leverage prior nonclinical data when key variables are sufficiently similar such as the same edit type, similar cell source, related delivery approach, or comparable mechanism. But if there are material differences, the Agency may still expect new studies. 

When the FDA released the draft guidance entitled General Considerations for the Use of New Approach Methodologies in Drug Development in March 2026, the industry wondered how this approach for reducing animal studies would actually work in practice. With this most recent CGT guidance, there may be an actionable path to reducing the use of animals in nonclinical studies by reducing the need for unnecessary repetition and nonclinical data regeneration. 

Clinical Benefit for Rare and Orphan Disease 

The guidance explicitly noted that the prior knowledge approach may be especially helpful for rare/orphan diseases and other life-threatening illnesses, where small patient populations make traditional data generation difficult for drug developers. When it is hard to find patients, it is hard to generate sufficient clinical data. The regulatory implications include potentially more efficient clinical development programs and submissions, especially when prior clinical or platform experience can help justify dosing, monitoring, or other design features of a clinical study. 

Regulatory Roundup

Hopefully this guidance will create a clearer pathway for Sponsor companies to build upon existing evidence in the public realm and/or from their own internal programs and previous product data. This could potentially reduce not only overall development time but also reduce data duplication and redundancy. It may also allow the Agency to truly focus their review time on new data and reduce the need to spend time reviewing an LNP or a vector that is already well-known and understood. 

However, the guidance also raises the importance of providing robust bridging rationale and justification of product development similarities across a possible platform. It means careful documentation of the similarities and relevance inclusive of genome editing and off target risk assessment, as well as the value of early interaction with the Agency.

Crossing Into “Neverland”

At the start of the modern CGT era, as the first therapies were making their way to market, regular meetings and discussions with regulators took place. These discussions included what the future could look like.  

A question came up between the Sponsor company and the health authority about there ever being a day and time if gene therapy would become more “plug and play.” 

More specifically, once certain vectors were tested and used time and time again, would it be possible to only change out and test the transgene insert and not the entirety of the whole therapy over and over again: capsid, vector, transgene, LNP, etc. Is there a future where the delivery vector and capsid remain the same, and are generally recognized as safe, but only the transgene itself is replaced and tested to target a specific disease? Does the proverbial wheel have to be reinvented and retested for every road traveled, or can the same wheel be used to travel to a different destination? 

At first, the room fell silent and the question hung in the air. Then some chuckles began to bubble up from the panel attendees as the question was fully digested. The response was “No. That will never be possible. That will never happen. Gene therapy is too new, too cutting edge, and too much is unknown. There is too much uncertainty and too much risk. No health authority would ever be comfortable with that type of development for gene therapy. Never.”

The June, 2026 FDA guidance officially welcomes the CGT industry to “Neverland.”

Welcome … So, Now What?

Arriving in “Neverland” is not a passive achievement. It requires active expertise. 

The old regulatory model was one of completeness: generate all data, submit all documentation, let the Agency review the totality. The process was slow but necessary.

But now we are in new somewhat uncharted territory. The new model demands something more rigorous: the ability to construct and defend a scientifically sound comparative case across program boundaries. It has the potential to unleash many closed doors in medicine.

However, playing the long game and implementing smart early planning have become “must haves” instead of a “nice to haves.” It shifts the skill set required of quality and regulatory professionals, as well as development teams. 

Companies are no longer developing a single product; they are building platforms, and platforms require platform thinking. This requires development teams to now master breadth as well as depth during the development process. They must understand genome editing principles, vector comparability, manufacturing platform architecture, and the specific mechanisms by which prior data transfers to new applications. 

Your pre-IND interactions with the FDA will hinge on whether you can articulate why your bridging rationale is scientifically sound and what components are re-usable, not simply whether you’ve checked every box. For organizations committed to staying ahead in the CGT space, this inflection point signals an investment in training, understanding, planning and capability-building. 

The question is no longer “Can we do this?” The question now is: “How quickly can development teams navigate the new landscape?” 

About the Author

Julie K. Hagan, MS, is President & Owner of Anchor Regulatory Consulting, LLC. With more than 20 years of experience, Julie is a Regulatory Affairs Professional  specializing in Orphan Indications, Rare Diseases, Gene Therapies (AAV, CRISPR/Cas9), RNA/LNP, Autologous Cell Therapy, Fast Track Designation (FTD) applications, Orphan Drug Designation (ODD) applications, RMAT applications, Monoclonal antibodies, Good Laboratory Practice (GLP), GMP, and Good Clinical Practice (GCP). Find her on LinkedIn.