FDA's new prior knowledge guidance: why rare disease gene therapy no longer has to start from zero

For many rare disease families, every new therapy feels like building from scratch. FDA's draft guidance on prior knowledge points to a more connected path, where what we learn in one genome editing program can help carry the next one forward.

Why does every rare disease therapy feel like starting over?

A diagnosis is the beginning of a long road. For families facing a rare or ultra-rare genetic disease, that road has often looked the same each time. A new team. A new manufacturing plan. A new safety package. A new investigational new drug application, or IND. And a new request to use data that someone, somewhere, has already generated.

Each of those steps takes time. For families, time is the one thing in shortest supply.

Part of the reason is structural, and it comes from a good place. For years, the relationship between a developer and FDA has worked a little like a confessional. A company can tell FDA detailed, private information about its product, its manufacturing process, and its safety data. FDA can review it, understand it, and rely on it for that company's product. But FDA generally cannot turn around and share that confidential knowledge with the next researcher, foundation, or family working on a similar problem.

That confidentiality protects the people who do the hard, expensive work of generating data, which matters. It also has a side effect: useful knowledge has tended to stay locked inside individual programs.

What is a "right of reference," and why has it mattered?

When one group wants to build on confidential data that another group already submitted to FDA, the usual tool is a right of reference.

A right of reference is permission. It lets one sponsor authorize FDA to use information from an existing regulatory file, such as an IND or a drug master file, to support a different submission. It is genuinely useful, and it has helped many programs move forward.

But it has limits. A right of reference can be slow to negotiate. It can be incomplete. And it depends entirely on whether the original data holder agrees to grant it. If they say no, or simply never respond, the next program may have to regenerate work that already exists. For a disease that affects a handful of people in the world, that kind of duplication is not just inefficient. It can be the difference between a therapy reaching a child in time and not.

What FDA's prior knowledge guidance actually changes

FDA has issued a draft guidance titled "Leveraging Prior Knowledge in the Development of Human Gene Therapy Products Incorporating Genome Editing." It is a meaningful step toward a more connected model of development.

The guidance focuses on gene therapies that use genome editing, the tools that can correct or rewrite DNA directly inside cells, delivered either outside the body (ex vivo) or inside it (in vivo). FDA also noted that some of the thinking may be informative more broadly, including for certain AAV and nanoparticle-based gene therapies.

Here is the core idea, in plain language: not every genome editing program should have to prove the same foundational science over and over. The guidance describes two kinds of prior knowledge a developer may use to support a new program.

Public knowledge. Information that is already published and openly available, such as peer-reviewed studies and the established scientific understanding of a tool or mechanism.

Platform knowledge. Accumulated experience with a well-understood, reproducible technology, including manufacturing, nonclinical, and clinical data that a sponsor has gathered across earlier programs.

When the science is similar enough, FDA's framework allows that prior knowledge to help support a new submission, with the goal of making review more efficient and accelerating development across multiple programs.

FDA notes that the ability to leverage prior knowledge may be especially helpful for genome editing products meant to treat rare diseases, many of which are serious and life threatening.

Public knowledge vs. platform knowledge: a simple way to think about it

If the confessional explains why knowledge gets locked away, a second picture helps explain what the guidance lets travel between programs. Imagine each genome editing therapy as a building.

Public knowledge is the shared engineering science everyone can use: how the materials behave, what makes a foundation safe, the physics that does not change from one building to the next.

Platform knowledge is your own crew's hard-won experience. Once you have built several houses with the same proven method, you do not re-derive how the method works each time. You carry that experience forward and spend your energy on what is genuinely new about the next build.

The new guidance is FDA acknowledging, in a structured way, that both kinds of knowledge can responsibly travel from one program to the next.

What this means for rare disease families

The promise here is not a shortcut around safety. FDA still expects a clear scientific rationale showing exactly why a given piece of prior knowledge applies to this product, this edit, and this patient situation.

What it does offer is the beginning of a future with fewer silos and less duplication. A more realistic path from diagnosis to a therapy strategy. And a recognition that personalized genetic medicine, including therapies built for a single child, deserves a development system designed for that reality, not one borrowed from mass-market drugs.

A genetic diagnosis names the condition. A mechanism explains what is going wrong. Prior knowledge helps carry useful evidence from one program to the next, so the next family does not have to begin at zero.

This guidance is part of a larger shift

FDA's prior knowledge guidance does not stand alone. It joins a growing set of frameworks built specifically for small populations and individualized therapies.

Human Gene Therapy for Rare Diseases, FDA's guidance on manufacturing, preclinical, and clinical design for rare disease gene therapy programs.

The Platform Technology Designation Program, established under Section 506K of the Federal Food, Drug, and Cosmetic Act, which creates a pathway to formally recognize a well-understood, reusable technology.

A set of guidances for individualized antisense oligonucleotide (ASO) therapies, the same family of n-of-1 medicines pioneered by milasen, the treatment designed for a single child named Mila.

Read together, these point in one direction: a regulatory system that is learning how to let knowledge compound, rather than reset, with every new program.

The bottom line

For rare disease families, useful knowledge should not stay locked away forever. FDA's prior knowledge guidance is an encouraging signal that the system is moving toward something more connected, more efficient, and more honest about what these families are up against.

At Nome, this is the future we are building for. Every program we run is designed to capture what we learn and carry it forward, so each new family benefits from the work that came before. The less often we start from zero, the faster the next therapy reaches the person waiting for it.

About Nome

Nome Therapeutics is the Operating System for Personalized Therapeutics, turning every rare disease patient's genome into an actionable treatment plan and helping execute on it at the lowest cost and highest speed in the industry.

References

1. FDA. Leveraging Prior Knowledge in the Development of Human Gene Therapy Products Incorporating Genome Editing; Draft Guidance for Industry. fda.gov

2. FDA. Human Gene Therapy for Rare Diseases; Guidance for Industry. fda.gov

3. FDA. Platform Technology Designation Program for Drug Development; Draft Guidance for Industry. fda.gov

4. FDA. IND Applications for Clinical Treatment: Contents and Format. fda.gov

5. FDA. Guideline for Drug Master Files. fda.gov

6. FDA. Guidance Documents for Rare Disease Drug Development. fda.gov

7. FDA. IND Submissions for Individualized Antisense Oligonucleotide Drug Products for Severely Debilitating or Life-Threatening Diseases: Clinical Recommendations. fda.gov

8. FDA. IND Submissions for Individualized ASO Drug Products: Chemistry, Manufacturing, and Controls Recommendations. fda.gov

9. FDA. IND Submissions for Individualized ASO Drug Products: Administrative and Procedural Recommendations. fda.gov

10. Kim J, et al. Patient-customized oligonucleotide therapy for a rare genetic disease. N Engl J Med. 2019;381:1644-1652. nejm.org

11. National Organization for Rare Disorders (NORD). Rare Disease Information and Resources. rarediseases.org