Dr. Powell on Remaining Questions With Interstitial Lung Disease in HER2+ Breast Cancer

Charles Powell, MD, MBA, director of the Mount Sinai-National Jewish Health Respiratory Institute, and a professor of medicine, pulmonary, and critical care and sleep medicine at Mount Sinai, discusses remaining questions with interstitial lung disease (ILD) in HER2-positive breast cancer.

Patients with HER2-positive breast cancer who are treated with fam-trastuzumab deruxtecan-nxki (Enhertu) are at risk of developing ILD. However, it is not known why antibody-drug conjugates can cause pulmonary toxicities, says Powell. It is likely that ILD is an off-target effect of trastuzumab deruxtecan because HER2 is not solely expressed on cancer cells, Powell explains.

However, why only a subgroup of patients with HER2-positive breast cancer develop ILD from trastuzumab deruxtecan is unknown, says Powell. This is similar to the fact that only a subgroup of smokers will develop smoking-related lung diseases, such as chronic bronchitis, emphysema, or lung cancer, Powell explains. Ultimately, more research is needeed to inform which patients are at higher risk for developing pneumonitis with trastuzumab deruxtecan, Powell concludes.