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Regulatory Toxicology for Advanced Gene Therapies

PROVEN INTELLIGENCE IN GENE EDITING TOXICOLOGY.

Regulatory Toxicology for Advanced Gene Therapies

CELL & GENE | RNA | BIOLOGICS

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Executive Summary

Preclinical programs for base and prime editors require a tailored strategy that addresses unique safety considerations beyond standard gene replacement therapies. Key areas of focus include quantifying off-target editing events, assessing potential immunogenicity of the nuclease components, and evaluating the long-term durability of the intended edit. This page outlines the pharmacological and toxicological frameworks necessary for advancing these next-generation therapies toward successful IND, IMPD, and other global regulatory submissions.

Frequently Asked Questions

What are the primary toxicology concerns for IND-enabling studies of base and prime editors?

The primary concerns involve assessing off-target and non-target editing events in relevant tissues, evaluating potential immunogenicity against the Cas nuclease or other protein components, and determining the biodistribution of the delivery vector (e.g., LNP or AAV). A robust preclinical program must quantify these risks in appropriate in vivo models under GxP conditions.

How does Franklin Biolabs tailor a preclinical strategy for a novel gene editing therapeutic?

A standard template does not exist. We design each program based on the specific editor, delivery modality, and target indication. This involves selecting the correct animal models, developing custom analytical methods to detect editing events, and designing studies that meet harmonized ICH guidelines for submissions to global authorities like the FDA and EMA.

Can you support both viral and non-viral delivery systems for gene editing payloads?

Yes. Our teams have deep experience in the preclinical evaluation of both AAV vectors and lipid nanoparticle (LNP) delivery systems. We apply this foundational knowledge to de-risk the delivery component of your therapeutic, allowing the toxicology program to focus on the unique biology of the editing payload itself.

Tailored Pharmacology & Toxicology Programs for Base and Prime Editors

The advancement of base and prime editing platforms offers high precision in correcting pathogenic mutations. Their pathway to the clinic requires a nonclinical safety program that is scientifically rigorous and customized to the modality. A successful program moves beyond simple dose-finding to interrogate the specific potential liabilities of the editing machinery itself.

Our approach is built on a deep history of characterizing novel biologic entities. Foundational work in defining a wide therapeutic window for AAV-delivered transgenes (PMID: 28319445) provides the framework for assessing the pharmacology of a therapeutic editor. This experience informs the design of studies that establish proof-of-concept and define a safe starting dose.

A marketing flyer for Franklin Biolabs detailing their immunogenicity services, including various assays and support for cell and gene therapy clinical trials.

A scientist in a sterile laboratory setting uses a multichannel pipette to transfer pink liquid into a multi-well plate for a high-throughput experiment.

De-Risking Immunogenicity and Off-Target Events

A primary consideration for any CRISPR-derived editor is the potential for an immune response to the nuclease component. Our experience in evaluating and mitigating immunogenicity for novel viral vectors in nonhuman primate models (PMID: 19812149) is directly applicable. We design studies to characterize immune responses and their potential impact on efficacy and safety.

For any gene editor, the preclinical program must rigorously assess two key safety questions:

  • Off-Target Editing: Unintended edits at locations in the genome that are similar to the target sequence.

  • Non-Target Tissue Biodistribution: The presence of the delivery vector and editing machinery in tissues outside the intended target organ.

Assessment Category Base Editor Considerations Prime Editor Considerations
Primary Pharmacology Quantify on-target editing efficiency; assess durability of the base conversion. Measure on-target insertion/deletion efficiency; confirm correct sequence integration.
Safety Pharmacology Standard battery of CNS, respiratory, and cardiovascular assessments. Standard battery of CNS, respiratory, and cardiovascular assessments.
Toxicology Evaluate for off-target editing; assess non-target tissue biodistribution. Characterize potential for larger unintended insertions/deletions; assess off-target activity.
Immunogenicity Characterize host immune response to deaminase and Cas nuclease domains. Characterize host immune response to reverse transcriptase and Cas nuclease domains.

NHP Models and Commitment to Animal Welfare

For many programs, nonhuman primate (NHP) models provide the most predictive data on immunogenicity and biodistribution. Our comprehensive animal welfare program is central to our operations and includes a firm commitment to the 3Rs (Replacement, Reduction, and Refinement).

This capability, combined with a 100% successful IND rate since 2019 achieved by our core scientific leadership, enables us to help sponsors navigate the 18-24 month journey to IND. Franklin Biolabs was formally launched in 2024, and this track record reflects the deep prior history of our principal scientists and study directors in the field. Our work is conducted in-house within our >100,000 sq ft GxP-compliant facility, ensuring data integrity for global regulatory filings.

This program is part of our comprehensive Preclinical and Translational Services.

Scientific Process Diagram

This content is for informational purposes. For guidance specific to your therapeutic program, please contact our team for a consultation.

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