Trastuzumab deruxtecan (TDXD) and datopotamab deruxtecan (Dato-DXd) share the same cytotoxic payload, yet Dato-DXd has a much lower rate of interstitial lung disease (ILD). This indicates the toxicity is driven by the antibody-antigen interaction, not the payload itself.

Contrary to the belief that any interstitial lung disease (ILD) requires permanent discontinuation of TDXD, data shows patients with asymptomatic, radiographically-identified Grade 1 ILD can be safely rechallenged. Treatment is paused and the patient is treated, but therapy can resume once resolved. Symptomatic ILD, however, requires permanent discontinuation.

For urothelial cancer patients treated with trastuzumab deruxtecan (TDXD), developing symptomatic (Grade 2) interstitial lung disease or pneumonitis is a critical event. Following protocols from other cancers, this requires permanent discontinuation of the therapy. Re-challenging the patient with TDXD after a Grade 2 event is not recommended without more disease-specific safety data.

The discovery of low-grade, asymptomatic interstitial lung disease (ILD) on scans for patients on certain ADCs does not mandate permanent discontinuation. By holding the drug, initiating steroids, and involving pulmonology, the inflammation can resolve, often allowing the patient to safely resume a highly effective therapy.

To manage the risk of interstitial lung disease (ILD) with TDXD, experts now recommend routine screening with high-resolution chest CT scans every 6-12 weeks. This practice aims to catch asymptomatic, grade 1 ILD early, allowing for treatment holds and steroid intervention, which may preserve the option to rechallenge.

Interstitial Lung Disease (ILD) is a significant risk with TDXD. However, a history of a completely resolved grade 1 event does not automatically preclude a patient from receiving the drug again. Clinicians may consider a re-challenge, balancing the risk against the lack of other viable therapies.

Given the risk of interstitial lung disease (ILD) with TDXD, clinicians should consider a baseline pulmonology consult for NSCLC patients with pre-existing lung issues. This proactive step helps establish a baseline and can prevent mismanaging potential adverse events.

Contrary to initial fears, both clinical trial and real-world data show that patients experiencing asymptomatic, grade 1 interstitial lung disease (ILD) from TDXD can be safely retreated. This allows patients to continue benefiting from a highly effective therapy without undue risk.

The risk of serious interstitial lung disease (ILD) with the drug TDXD is heavily dependent on the total duration of therapy. A short, 4-cycle neoadjuvant course has a low 4% ILD rate, whereas a longer 14-cycle adjuvant course sees this risk more than double to over 10%, making the shorter pre-surgical approach significantly safer.