Overview

ADCs combine the high specificity of monoclonal antibodies with the high activity of small molecule cytotoxic drugs to improve the targeting of tumor drugs. CD BioGlyco has extensive experience to fit the specific needs of clients in the development of glycosylation site-specific ADCs.

ADC is a drug that combines the high specificity of monoclonal antibodies with the high activity of small molecule cytotoxic drugs to improve the targeting of tumor drugs and reduce toxic side effects. At present, the development of ADCs has gone through three stages: 1) The first-generation ADCs use mouse-derived antibodies or chimeric antibodies and use non-site-directed conjugation technology, resulting in poor efficacy, strong toxic side effects, strong immunogenicity, and short half-life; 2) The second-generation ADC is improved based on the first-generation ADC and monoclonal antibodies with better antigen affinity are selected to improve the targeting of tumor cells and reduce cross-reaction with normal tissues. Second-generation ADCs have higher targeting, higher efficacy, and lower immunogenicity. However, there are still problems such as strong toxic side effects, drug resistance, and high drug-to-antibody ratio (DAR); 3) The third-generation ADC uses small molecule toxicants and human monoclonal antibodies for site-specific coupling, and the DAR value is more uniform. And there are many differentiated small molecule poisons to choose from. Compared to the previous two generations of ADCs, the stability and pharmacokinetics are greatly improved, the drug activity is higher, and the toxicity is lower.

Key Technologies

Employing a proprietary orchestration of enzymatic and chemical intelligence, our platform synthesizes antibody-drug conjugates of exceptional consistency and quality. Initial stages employ enzymatic remodeling of native N-linked glycans at the conserved Asn-297 locus. A curated enzymatic cascade—incorporating endoglycosidases for glycan truncation to a terminal GlcNAc residue—establishes a homogeneous glycan architecture primed for subsequent functionalization.

Thereafter, glycosyltransferases append synthetic monosaccharides bearing non-native bioorthogonal moieties (e.g., azides or alkynes). This introduces a specific conjugation handle absent in endogenous biomolecules, enabling selective linkage. The ultimate conjugation leverages click chemistry—azide-alkyne cycloaddition under physiocompatible aqueous conditions—to forge stable triazole bridges between antibody and drug-linker constructs.

This chemoenzymatic triad ensures precise, high-fidelity ADC synthesis absent genetic manipulation, preserving structural and functional integrity of the parental immunoglobulin while achieving near-stoichiometric conjugation yields.

Enzymatic Precision: Where Sugars Anchor Cures.

The third-generation ADC mainly focuses on selecting unique amino acid sites and using unique molecules or performing site-specific coupling through proximity effect, mainly including the following 4 types: 1) Interchain disulfide bond modification; 2) Glycosylation site-specific conjugation; 3) Chemoselective modification; 4) Proximity-based modification. At CD BioGlyco, we provide ADC development services based on the enzymatic modification of glycans for our clients. The specific strategies are as follows:

• Treatment of antibody glycans by β1,4-galactosyltransferase (β1,4-GalT) and α2,6-sialyltransferase (α2,6-SiaT) yields products with monosialylated glycans. These glycans are then oxidized by periodate and conjugated to aminooxy drugs.

• To eliminate the need for periodate treatment, an azide-modified sialic acid derivative at the C9 position is incorporated into antibody N-glycans, using the substrate tolerance of sialyltransferases. The cyclooctyne-conjugated biotin, fluorophore, or cytotoxic drug is then reacted with the azide-containing antibody to form ADC with DARs of 3.5-4.5.

• Transfer of N-azidoacetylgalactosamine (GalNAz) to substrates containing N-acetylgalactosamine (GalNAc) by β1,4-GalT mutants. The modified antibody is then attached to the payload via copper-free click chemistry, resulting in a highly stable and homogeneous ADC.

Workflow

• Project Assessment and Strategy

We begin with a detailed consultation to understand your specific antibody and payload. Our team of experts will then design a custom development plan, including the selection of the most suitable enzymes and drug-linker for your project.

• Glycan Remodeling and Activation

Your antibody is treated with our proprietary enzyme cocktail to prepare the glycan for modification. This is a critical step that removes the heterogeneous native glycans and introduces a uniform, reactive handle for conjugation.

• Conjugation and Purification

The activated antibody is then conjugated to your chosen drug-linker using highly efficient click chemistry. The resulting ADC is rigorously purified to remove any unconjugated species and ensure a pristine final product.

• Characterization and Preclinical Evaluation

The final ADC is comprehensively characterized using a suite of advanced analytical techniques, including mass spectrometry and HPLC. We offer a full range of in vitro and in vivo studies to evaluate the ADC's stability, potency, and pharmacokinetics, providing the data needed for successful preclinical and clinical development.

Publication Data

Advantages

• The use of a highly stable triazole linkage ensures that the drug payload remains securely attached to the antibody in circulation, minimizing off-target toxicity and dramatically enhancing the therapeutic index.
• This service can be used in creating homogeneous ADCs with precise drug-to-antibody ratios by enzymatically modifying glycans for targeted payload attachment.
• This service can be used in incorporating azide-modified sialic acid into antibodies via enzymes, allowing copper-free "click chemistry" for stable ADC assembly without chemical oxidation.

Application

• ADC development enables site-specific drug delivery and multifunctional agents.
• ADCs integrate diagnostic tracking with therapy:
  • Fluorescent ADCs: Near-infrared dye-conjugated ADCs enable real-time monitoring of drug distribution and tumor targeting.
  • pH-sensitive probes: Tandem fluorescent systems visualize ADC intracellular trafficking and payload release dynamics.

Frequently Asked Questions

Associated Services

Glycan enzymatic modification-based ADC development harnesses precise glycosyltransferase engineering to create homogeneous antibody-drug conjugates with optimized therapeutic profiles. To ensure the safety and efficacy of all biotherapeutic components—from complex biologics to critical small-molecule adjuvants—we extend our analytical expertise to pharmaceutical analysis, including:

CD BioGlyco is committed to providing ADC development services utilizing glycosylation site-specific conjugation technology to meet the research needs of our clients. If you have glycan enzymatic modification-based ADC development services, please feel free to contact us for more information.

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