# Drug-to-antibody ratio (DAR)

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

## TL;DR

The drug-to-antibody ratio (DAR) is how many payload molecules ride on each antibody, typically 2 to 8.

## Summary

The drug-to-antibody ratio, or DAR, is the number of payload molecules attached to each antibody in an antibody-drug conjugate, typically between 2 and 8. A higher DAR delivers more drug per binding event, as with T-DXd at roughly 8 and sacituzumab at about 7.6, but it increases hydrophobicity, aggregation and clearance unless hydrophilic linkers compensate. Site-specific conjugation gives a homogeneous DAR, which improves pharmacokinetics. The term belongs to the Antibody-drug conjugate (ADC) and Site-specific conjugation & linker chemistry technologies, is picked up by the Hydrophilic next-generation linkers term, and appears in the DESTINY-Breast03 paper and the idea on ADC dose and schedule optimisation trials.

## Fields

- Kind: Term
- Last checked: 2026-09-04
- Also known as: drug-to-antibody ratios

## 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/)
- ideas: [Dose and schedule optimisation trials specific to antibody-drug conjugates](https://onco.cc/ideas/idea-tr1-adc-dose-and-schedule-optimisation/)
- key papers: [DESTINY-Breast03: trastuzumab deruxtecan beats T-DM1 as second-line treatment of HER2-positive metastatic breast cancer](https://onco.cc/key-papers/paper-destiny-breast03-nejm-2022/)
- terms: [Hydrophilic next-generation linkers (TMALIN, Dolaflexin, sulfonyl-pyrimidine, PEG-containing)](https://onco.cc/terms/hydrophilic-next-gen/)

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