Off-Target Activity Assessment Service
Overview
As the landscape of oligonucleotide therapeutics expands from rare genetic disorders to common metabolic diseases, the imperative for rigorous safety profiling has never been higher. CD BioGlyco provides an industry-leading off-target activity assessment service, specifically engineered to de-risk RNA-based drug candidates early in the development cycle. While delivery technologies like GalNAc clusters have solved the tissue-targeting challenge, the intracellular specificity of the RNA payload remains a critical variable. Our service identifies and quantifies unintended hybridization events, passenger strand loading, and innate immune activation. By integrating advanced transcriptomics with proprietary bioinformatic pipelines, we ensure that your lead candidates possess the highest possible therapeutic index before moving into costly clinical phases.
Core Technologies
Our assessment platform utilizes a multi-layered approach to detect unwanted molecular interactions at every biological level:
- In Silico Prediction Algorithms
Our algorithms incorporate thermodynamic binding energies, seed-region complementarity, and mRNA accessibility motifs to predict potential off-target sites across the entire human transcriptome.
- High-Depth RNA-Seq (Transcriptomics)
To validate predicted off-targets, we perform genome-wide expression profiling. By comparing treated and untreated cell populations, we identify differentially expressed genes (DEGs) that signify secondary silencing effects or compensatory cellular pathways.
- GEnO-seq (Global Evaluation of Oligonucleotide Specificity)
This specialized sequencing technique captures the direct interaction between the oligonucleotide and its unintended RNA targets in a cellular context. It provides a "physical map" of where the ASO or siRNA is actually binding, independent of downstream expression changes.
Off-Target Activity Assessment: Ensuring Safety and Specificity in RNA Therapeutics
Our service is a comprehensive analytical package designed for the modern biotech pipeline. Our scope covers the full spectrum of oligonucleotide modalities, including siRNA, antisense oligonucleotides (ASOs), microRNA (miRNA) mimics, and aptamers. We provide assessment services across multiple species, including human, non-human primate (NHP), and rodent genomes, allowing for cross-species safety comparisons that are vital for IND filings.
A key pillar of our service is the focus on "Seed-Region" toxicity. Most siRNA off-targeting is driven by the 2nd to 8th nucleotides of the guide strand. Our scope includes specialized "Seed-Vulnerability" mapping to identify sequences prone to microRNA-like effects. Additionally, we evaluate the risk of passenger strand loading (for siRNAs) and the potential for ribonuclease H (RNase H)-mediated cleavage at non-target sites (for ASOs). We also offer customized assays to detect the activation of innate immune sensors, such as Toll-like receptors (TLRs), ensuring that your candidate doesn't trigger unexpected inflammatory responses.
Workflow
Candidate Screening & In Silico Analysis
Our process begins with a comprehensive in silico screening of your RNA sequence library. We utilize advanced bioinformatic platforms and proprietary algorithms to cross-reference your sequences against extensive, up-to-date genomic and transcriptomic databases. This analysis predicts and ranks potential off-target binding sites based on sequence complementarity, prioritizing candidate molecules that demonstrate the lowest theoretical off-target burden and the highest predicted specificity for your intended target, thereby de-risking the initial selection.
In Vitro Cell-Based Assays
Top candidate sequences are advanced to rigorous in vitro testing. We employ high-efficiency transfection methods to deliver the RNA into relevant cell models, such as primary hepatocytes for liver-targeted GalNAc conjugates. To maximize the detection of rare or weak off-target events, assays are performed under "super-physiological" conditions, using doses significantly higher than the therapeutic range to deliberately force and amplify potential off-target interactions, ensuring a sensitive and stringent assessment of specificity.
Whole-Transcriptome Sequencing
Following the cell-based assay, total RNA is extracted and prepared for next-generation sequencing. We employ deep-coverage, strand-specific whole-transcriptome sequencing (RNA-seq) to obtain an unbiased, genome-wide profile of gene expression changes. This high-sensitivity approach is critical for capturing even subtle alterations in low-abundance transcripts that, while potentially missed in standard assays, could pose significant long-term safety or efficacy concerns.
Bioinformatic Filtering & Enrichment
The resulting sequencing data undergoes sophisticated bioinformatic processing. Our specialized pipeline employs statistical models to differentiate between primary, direct off-target silencing (caused by RNAi-mediated mRNA cleavage or steric blockade) and secondary, indirect transcriptional responses resulting from pathway modulation or cellular feedback. This critical filtering step produces a curated, high-confidence list of "primary off-targets" for downstream validation, removing confounding biological noise.
Validation via qPCR/Western Blot
The most relevant off-target candidates identified, typically those with high fold-change or those involving genes of toxicological concern, are subjected to orthogonal validation. We employ quantitative PCR (qPCR) to precisely measure changes in mRNA levels and Western blot analysis (or other protein quantification methods) to assess the corresponding impact at the protein level. This confirmatory step, performed at therapeutically relevant doses, verifies the magnitude and biological relevance of the off-target effect.
Comprehensive Safety Reporting
You receive a final, integrated safety assessment dossier. This report includes a proprietary "specificity score" for each candidate, a detailed risk assessment evaluating the implications of identified off-targets for clinical translation, and data-driven optimization recommendations. These recommendations may include specific sequence modifications, chemical adjustment strategies, or dosage considerations to enhance specificity and advance the most promising, safe candidate forward.
Publication Data
Journal: SLAS Discovery
DOI: 10.1016/j.slasd.2025.100254
IF: 2.7
Published: 2025
Results: This review article provides a comprehensive analysis of the off-target effects associated with oligonucleotide therapeutics, such as ASOs and siRNAs, which pose a significant challenge to their clinical development despite their high specificity. The authors systematically classify these unintended toxicities into hybridization-dependent effects (e.g., partial complementarity to non-target RNAs) and hybridization-independent effects (e.g., immune activation, hepatotoxicity), while also summarizing relevant regulatory guidelines from agencies. A major contribution of the work is its proposal of a structured preclinical assessment framework, which integrates in silico predictions, in vitro assays (e.g., cytotoxicity, immunogenicity), and in vivo models to evaluate and mitigate off-target risks. By analyzing data from approved oligonucleotides, the review highlights the translational gaps between nonclinical findings and clinical adverse events, emphasizing that a systematic evaluation strategy is essential for improving the safety profile and clinical success of these promising therapeutic agents.
Applications
Cardiovascular RNAi Therapeutics Research
We assess the specificity of siRNAs targeting the liver (e.g., PCSK9, ANGPTL3) to ensure that gene silencing is confined only to the target mRNA, avoiding systemic metabolic disruption.
Oncology Drug Discovery
Our service identifies off-target silencing of tumor suppressors or essential cell-cycle regulators, preventing unintended toxicities that could compromise the safety of RNA-based cancer treatments.
Rare Disease Gene Modulation
For ASOs targeting rare enzyme deficiencies, we provide deep-dive analysis to ensure that the required high doses do not lead to non-specific RNase H cleavage in non-target organs.
Antiviral RNA Research
We help researchers design highly specific siRNAs against viral genomes (like HBV or HIV) while ensuring no cross-reactivity with the human host transcriptome occurs during the treatment period.
Advantages
Unmatched Bioinformatic Depth
Our in silico tools go beyond simple sequence matching by integrating thermodynamic parameters and RNA structural data. This ensures we catch potential off-targets that traditional search tools often miss.
High-Sensitivity Detection Limits
We utilize deep-coverage RNA-Seq (up to 100M reads per sample) to identify low-level transcriptomic changes. This sensitivity is critical for identifying subtle off-targets that could lead to chronic toxicity.
Direct Binding Evidence
With technologies like GEnO-seq, we provide physical proof of oligonucleotide-RNA interactions. This distinguishes direct off-target silencing from indirect downstream cellular stress responses.
Passenger Strand De-risking
For siRNA projects, we specifically analyze the potential for the passenger strand to enter the RISC complex. This prevents unintended silencing caused by the "carrier" strand of the duplex.
Frequently Asked Questions
Customer Review
The off-target analysis from CD BioGlyco was pivotal for our lead selection. They identified a seed-based interaction with a vital cell-cycle gene that we completely missed in silico.
— By Dr. S.Y., Head of Oligonucleotide Discovery
I was impressed by their GEnO-seq technology. Being able to see exactly where our ASO was binding across the genome gave us the safety confidence we needed to move forward.
— By Dr. K.M., Senior Principal Scientist
The 'Specificity Index' is a great tool. It allowed us to rank our 15 siRNA candidates clearly and choose the one with the best therapeutic window for our rare disease project.
— By Dr. P.L., Associate Professor
Associated Services
High-potency liver targeting paired with our advanced specificity screening for maximum safety.
Optimized antisense oligonucleotides with enhanced stability and hepatocyte-specific delivery.
Precision microRNA mimics and inhibitors designed to modulate complex regulatory networks safely.
High-affinity RNA aptamers for targeted delivery of therapeutic payloads or diagnostic imaging agents.
CD BioGlyco is dedicated to the philosophy that a therapeutic is only as good as its safety profile. Our off-target activity assessment service represents the gold standard in oligonucleotide de-risking, providing the clarity and precision needed to advance RNA-based drugs with confidence. Don't let unintended interactions compromise your clinical success. Contact us to ensure your candidates are as specific as they are powerful.
Reference
- Ruan, H.; et al. Off-target effects of oligonucleotides and approaches of preclinical assessments. SLAS Discovery. 2025, 100254. (Open Access)