# Interstitial lung disease (ILD) / pneumonitis

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

## TL;DR

Interstitial lung disease (ILD) is lung inflammation, a serious side effect of some ADCs (especially Enhertu) and immunotherapy.

## Summary

Occurs in ~10-15% of T-DXd patients (grade 5 in ~1%); also with Dato-DXd, HER3-DXd, checkpoint inhibitors, and mTOR inhibitors. Requires monitoring, prompt steroids, and permanent discontinuation for grade ≥2 with T-DXd. Mechanism with DXd is incompletely understood (alveolar macrophage uptake proposed).

## Fields

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

## Notes

- Two drugs used in triple-negative breast cancer can inflame the lungs: pembrolizumab (pneumonitis) and the deruxtecan antibody-drug conjugates (trastuzumab deruxtecan in HER2-low disease, datopotamab deruxtecan). In a pooled analysis of 1,150 people on trastuzumab deruxtecan, 15.4% developed drug-related interstitial lung disease, most low grade and 87% within the first 12 months, with 2.2% fatal. Macmillan's wording for pembrolizumab applies to both: breathlessness, a cough that does not go away, wheeze or a fever over 37.5 C means contacting the hospital straight away on the 24-hour number.

## Sources

- Wikipedia: https://en.wikipedia.org/wiki/Interstitial_lung_disease
- Wikipedia: https://en.wikipedia.org/wiki/Interstitial_lung_disease
- Powell et al., pooled analysis of interstitial lung disease in nine trastuzumab deruxtecan studies (ESMO Open 2022): https://doi.org/10.1016/j.esmoop.2022.100554
- Macmillan: pembrolizumab: https://www.macmillan.org.uk/cancer-information-and-support/treatments-and-drugs/pembrolizumab

## Connected records

- cancers: [Gastric & gastro-oesophageal junction cancer](https://onco.cc/cancers/gastric/), [HER2-low and HER2-ultralow metastatic breast cancer](https://onco.cc/cancers/her2-low-metastatic-breast-cancer/), [HER2-mutant non-small-cell lung cancer](https://onco.cc/cancers/her2-mutant-nsclc/), [HER2-positive breast cancer](https://onco.cc/cancers/breast-her2-positive/), [Lung cancer (all types)](https://onco.cc/cancers/lung-cancer/), [Triple-negative breast cancer (TNBC)](https://onco.cc/cancers/tnbc/), [Unresectable stage III non-small-cell lung cancer](https://onco.cc/cancers/stage-iii-unresectable-nsclc/)
- drugs: [Bleomycin](https://onco.cc/drugs/bleomycin/), [Datopotamab deruxtecan](https://onco.cc/drugs/datopotamab-deruxtecan/), [Trastuzumab deruxtecan](https://onco.cc/drugs/trastuzumab-deruxtecan/)
- trials: [DESTINY-Gastric04](https://onco.cc/trials/destiny-gastric04/), [DESTINY-Lung02](https://onco.cc/trials/destiny-lung02/)
- terms: [DXd](https://onco.cc/terms/dxd/), [Living with an antibody-drug conjugate: diarrhoea, blood counts, eyes and lungs](https://onco.cc/terms/adc-side-effects-breast/), [Palliation in advanced triple-negative breast cancer: brain, bone, pleura, skin and end of life](https://onco.cc/terms/tnbc-symptom-control-palliation/), [Pneumonitis](https://onco.cc/terms/pneumonitis/), [Therapeutic index (therapeutic window)](https://onco.cc/terms/therapeutic-index/), [Toxicity grade](https://onco.cc/terms/toxicity-grade/), [When to seek urgent help with triple-negative breast cancer (NHS 111 and 999)](https://onco.cc/terms/urgent-help-tnbc/)
- technologies: [Antibody-drug conjugate (ADC)](https://onco.cc/technologies/adc/)
- pairings: [Caution: DXd ADC + agents with pneumonitis risk](https://onco.cc/pairings/ild-overlap-caution/)
- bottlenecks: [Cachexia, toxicity and the limits of the patient](https://onco.cc/bottlenecks/b-cachexia-supportive/), [Toxicity and quality of life are undervalued](https://onco.cc/bottlenecks/b-toxicity-qol/), [Wrong doses](https://onco.cc/bottlenecks/b-dose-optimisation/)
- ideas: [Dose and schedule optimisation trials specific to antibody-drug conjugates](https://onco.cc/ideas/idea-tr1-adc-dose-and-schedule-optimisation/), [Linked human organ chips to predict side effects before people are dosed](https://onco.cc/ideas/idea-bio1-multi-organ-chip-tox/), [Test flat versus weight-based dosing of antibodies, and use dose banding to cut waste](https://onco.cc/ideas/idea-tr1-weight-based-vs-flat-dosing-trials/)
- 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/), [DESTINY-Breast04: trastuzumab deruxtecan works in HER2-low breast cancer, creating a new treatable group](https://onco.cc/key-papers/paper-destiny-breast04-nejm-2022/), [DESTINY-Breast06: trastuzumab deruxtecan before any chemotherapy in hormone-receptor-positive, HER2-low or ultralow breast cancer](https://onco.cc/key-papers/paper-destiny-breast06-nejm-2024/)

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