# Linker (ADC)

Source: https://onco.cc/terms/linker/  
OnCo record `linker` (Term). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

The linker is the chemical tether between antibody and payload. It must hold in the blood and let go inside the tumour.

## Summary

Cleavable linkers (protease-sensitive peptides like Val-Cit or GGFG, acid-labile hydrazones, glutathione-sensitive disulfides) release free payload; non-cleavable linkers (SMCC in T-DM1) release payload still attached to an amino acid, which cannot cross membranes. Linker hydrophilicity permits high DAR without aggregation.

## Fields

- Kind: Term
- Last checked: 2026-09-04

## Sources

- Wikipedia: https://en.wikipedia.org/wiki/Antibody-drug_conjugate
- Wikipedia: https://en.wikipedia.org/wiki/Antibody-drug_conjugate

## Connected records

- technologies: [Antibody-drug conjugate (ADC)](https://onco.cc/technologies/adc/), [Site-specific conjugation & linker chemistry](https://onco.cc/technologies/site-specific-conjugation/)
- drugs: [Inotuzumab ozogamicin](https://onco.cc/drugs/inotuzumab-ozogamicin/)
- ideas: [Platform designation for ADC linker-payloads so manufacturing data carry across](https://onco.cc/ideas/idea-reg-adc-platform-designation/)
- key papers: [ASCENT: sacituzumab govitecan doubles survival in heavily pretreated metastatic triple-negative breast cancer](https://onco.cc/key-papers/paper-ascent-nejm-2021/)
- terms: [Acid-labile hydrazone (AcBut)](https://onco.cc/terms/hydrazone/), [CL2A](https://onco.cc/terms/cl2a/), [Hydrophilic next-generation linkers (TMALIN, Dolaflexin, sulfonyl-pyrimidine, PEG-containing)](https://onco.cc/terms/hydrophilic-next-gen/), [Maleimidocaproyl (mc), non-cleavable](https://onco.cc/terms/mc-non-cleavable/), [mc-Val-Cit-PABC](https://onco.cc/terms/mc-vc-pabc/), [Prodrug](https://onco.cc/terms/prodrug/), [SMCC (thioether, non-cleavable)](https://onco.cc/terms/smcc/), [Sulfo-SPDB (disulfide)](https://onco.cc/terms/sulfo-spdb/), [Tetrapeptide GGFG (maleimide-GGFG-aminomethyl)](https://onco.cc/terms/ggfg/), [Val-Ala dipeptide](https://onco.cc/terms/val-ala/)

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JSON: https://onco.cc/api/v1/entities/linker.json