Dr Foldi on the Impact of ILD in HER2+ Breast Cancer Treatment

Julia Foldi, MD, PhD, assistant professor, medicine, Hematology/Oncology, Department of Medicine, University of Pittsburg Medical Center (UPMC), breast medical oncologist, UPMC Hillman Cancer Center, discusses interstitial lung disease (ILD) associated with the use of fam-trastuzumab deruxtecan-nxki (Enhertu; T-DXd) in patients with HER2-positive breast cancer.

The most concerning toxicity associated with T-DXd is ILD, Foldi begins, saying that in early clinical trials, before this adverse effect (AE) was fully understood, some deaths resulted from ILD. Consequently, oncologists have become highly attuned to the risk of this AE in this patient population, she emphasizes. In more recent trials, there has been significant emphasis on imaging surveillance to detect ILD, with oncologists typically increasing surveillance frequency with CT chest scans, Foldi says. Many oncologists now have increased this frequency, she notes, adding that she personally images patients approximately every 9 weeks to ensure that any asymptomatic ILD is detected early.

The reason for this increased surveillance is that if ILD is identified on imaging when still asymptomatic, it can be treated with steroids, Foldi continues. It also may be possible to rechallenge patients with T-DXd once the ILD has been resolved on imaging. However, if ILD progresses to a higher grade and becomes symptomatic, T-DXd rechallenge is not possible, even if symptoms and imaging findings resolve, according to the package insert and oncologists’ understanding of this toxicity, she elucidates.

For many patients, T-DXd is a highly effective treatment, so it is crucial to ensure patients remain on therapy for as long as possible, Foldi expands. Thus, increased ILD surveillance is essential. With this imaging approach, Foldi says she has become comfortable treating patients using T-DXd. It is also crucial to ask patients whether they are experiencing pulmonary symptoms, especially during the winter season, according to Foldi. Symptoms of ILD, such as a cough or shortness of breath, could be attributed to other causes, but any pulmonary symptom should be taken seriously in this context, and imaging should be done immediately, she concludes.