How do you differentiate between on-target and off-target cleavage events in a GxP environment?

We employ a suite of validated, orthogonal assays. On-target editing efficiency is quantified using next-generation sequencing (NGS) methods like amplicon sequencing. For off-target events, we use highly sensitive, unbiased techniques such as GUIDE-seq in vitro to nominate potential sites, which are then confirmed in vivo using targeted deep sequencing on GxP-compliant study samples. This multi-assay approach provides a comprehensive and defensible dataset for regulatory review.

What is your standard approach for quantifying potential chromosomal rearrangements post-CRISPR editing?

Our standard GxP testing battery includes classical cytogenetics, such as chromosomal aberration analysis and micronucleus assays, to detect large-scale structural changes. For higher resolution, we can deploy specialized NGS-based methods or Fluorescence In Situ Hybridization (FISH) to investigate specific translocation risks at the on-target site and at high-risk predicted off-target loci, providing a deeper view of genomic integrity.

How do you integrate biodistribution data with genotoxicity assessments for LNP-delivered CRISPR systems?

We design integrated study protocols where non-target tissue biodistribution data directly informs the sampling strategy for genotoxicity. Tissues showing the highest accumulation of the lipid nanoparticle (LNP) delivery vehicle are prioritized for off-target analysis via deep sequencing. This links exposure directly to potential genomic risk, creating a more robust safety narrative for IND submission.

What are the regulatory expectations for off-target nomination and validation for an IND submission?

Regulatory bodies expect a systematic, risk-based approach. This begins with comprehensive in silico prediction to nominate potential off-target sites, followed by empirical data from sensitive in vitro screening assays. The final step involves validating the highest-risk sites in vivo using samples from the definitive GxP toxicology study. The goal is to demonstrate a thorough investigation and provide a clear rationale for why any identified off-target events are considered to pose an acceptable risk.

For CRISPR/Cas9-based therapeutics, a comprehensive assessment of off-target cleavage and on-target genotoxicity is fundamental to building a successful Investigational New Drug (IND) application. Franklin Biolabs provides integrated, GxP-compliant workflows that combine unbiased screening with targeted in vivo validation to precisely characterize the genomic safety profile of your gene editing candidate. Our approach de-risks development programs by generating the robust, regulatory-grade data required for clinical progression.

The primary safety concern for any CRISPR/Cas9 therapeutic is the potential for unintended genomic alterations. These risks extend beyond simple off-target cuts and include complex on-target events such as large deletions, inversions, or chromosomal translocations that can occur during the DNA repair process.

A rigorous safety program must characterize both the specificity of the guide RNA and the full spectrum of outcomes at the intended editing site. This requires a multi-assay strategy capable of detecting a wide range of potential genetic changes with high sensitivity.

We utilize a phased approach to systematically identify and validate potential off-target liabilities, ensuring a thorough and efficient evaluation.

• Phase 1: In Silico Prediction: We begin by using validated computational algorithms to generate a comprehensive list of potential off-target sites based on sequence homology to the guide RNA.

• Phase 2: In Vitro Screening: The nominated sites are then screened using sensitive, unbiased cell-based assays (e.g., GUIDE-seq, CIRCLE-seq) to empirically identify loci that undergo cleavage.

• Phase 3: In Vivo Confirmation: The highest-risk sites identified in vitro are subjected to targeted deep sequencing using genomic DNA isolated from tissues collected during formal GxP toxicology studies.

The safety profile of a gene editing therapeutic is intrinsically linked to its delivery system. The choice of vehicle, such as a lipid nanoparticle (LNP), governs the non-target tissue biodistribution and duration of exposure to the CRISPR/Cas9 machinery. As highlighted in recent literature (PMID: 39856035), innovations in delivery chemistry, such as the development of branched ionizable lipids to enhance endosomal escape, are key to improving therapeutic efficacy and specificity. A thorough safety assessment must correlate biodistribution data with off-target analysis in relevant tissues. Our collaborations with leading delivery platform developers ensure your program benefits from this integrated perspective.

Our >100,000 sq ft facility is equipped to conduct a full battery of GxP-compliant genotoxicity studies tailored for gene editing programs, supporting an 18-24 month IND timeline. Since the Franklin Biolabs brand launch in 2024, our scientific leadership has maintained a 100% IND success rate dating back to 2019.

All in vivo studies are conducted in full compliance with AAALAC and USDA guidelines. We are committed to the principles of the 3Rs (Replacement, Reduction, and Refinement) in the design and execution of every research program, ensuring the highest standards of ethical and scientific conduct.