Dr Bagegni on the Prevalence of ILD With Trastuzumab Deruxtecan in HER2+ Breast Cancer

Nusayba Bagegni, MD, assistant professor of medicine, Division of Medical Oncology, Washington University School of Medicine, medical oncologist, Siteman Cancer Center, discusses the prevalence of interstitial lung disease (ILD) in patients with HER2-positive breast cancer treated with fam-trastuzumab deruxtecan-nxki (Enhertu).

Although trastuzumab deruxtecan has been a transformative treatment option approved for select patients with metastatic HER2-positive and HER2-low breast cancer, ILD is a toxicity linked with the antibody-drug conjugate (ADC).

Bagegni notes that she has treated patients who have developed grade 1 ILD following treatment with trastuzumab deruxtecan. These patients received routine scans that detected ground-glass opacities, and in these cases, trastuzumab deruxtecan needed to be interrupted. Patients with grade 1 ILD may also be offered corticosteroids, Bagegni says.

Trastuzumab deruxtecan should be stopped for symptomatic patients with ILD, and they should also receive corticosteroids immediately, Bagegni explains. These patients should also be examined by a pulmonologist, who can conduct pulmonary function tests and evaluate for infectious disease, Bagegni adds.

In her experience managing patients with grade 1 ILD, Bagegni says a chest computed tomography (CT) scan approximately 4 weeks following the onset of toxicity is used to reassess the ILD and determine if the patient can resume treatment with trastuzumab deruxtecan. However, in symptomatic patients with grade 2 or higher ILD, if the adverse effect is determined to be related to trastuzumab deruxtecan, it is recommended that those patients discontinue therapy with the ADC, Bagegni explains. More investigations are needed to better understand which patients are at a higher risk for ILD and which patients could potentially be rechallenged with trastuzumab deruxtecan, Bagegni concluded.