CT Findings From Interstitial Lung Diseases in Patients With Metastatic Breast Cancer Treated With Fam-Trastuzumab Deruxtecan: A Single Institutional Experience

Multidisciplinary clinical guidelines in proactive monitoring, early diagnosis, and effective management of trastuzumab deruxtecan (T-DXd)-induced interstitial lung disease (ILD) in breast cancer patients

Trastuzumab deruxtecan (T-DXd), a human epidermal growth factor receptor 2 (HER2)-directed antibody-drug conjugate (ADC), has altered the treatment landscape in breast cancer (BC), irrespective of the HR-receptor status. The use of the agent is increasing, despite the finding that exposure to T-DXd increases the risk of interstitial lung disease (ILD), particularly in BC patients. Although T-DXd-related ILD can be potentially severe and life-threatening, most low-grade cases can be treated safely using a multidisciplinary approach comprising early and accurate diagnosis, effective management, close monitoring, and the prompt administration of steroids. Additionally, increasing patients' education on ILD symptoms ensures close attention and enables prompt reporting, enhancing patient outcomes. It is recommended that predictive biomarkers are assessed in patients with risk factors for developing ILD. Currently, diagnostic criteria comprise newly identified pulmonary opacities, the relation of symptom onset to medication initiation, and the exclusion of other causes of ILD. The general condition of patients is weakened during the management of ILD (BC progression and corticosteroid treatment). Consequently, BC chemotherapy might be attenuated. This highlights the importance of preventing (high-grade) ILD, especially since its use is expanded. Identifying high-risk patients, diagnosing, and customizing treatment is, however, challenging and additional information on patient selection is often not fully clarified. In this paper, we provide updated multidisciplinary clinical guidance for patient selection, proactive monitoring, early diagnosis, and effectively management of T-DXd-induced ILD in HER2-positive BC patients. We describe the risk factors for developing ILD, patients' characteristics of ILD, and the histopathological and radiographic characteristics of ILD, including real-world clinical practice reports. These recommendations provide a structured step-by-step approach for managing each suspected BC-related ILD grade.

Incidence of interstitial lung disease and cardiotoxicity with trastuzumab deruxtecan in breast cancer patients: a systematic review and single-arm meta-analysis

BACKGROUND

Trastuzumab deruxtecan (T-DXd) has been shown to benefit progression-free survival and overall survival in patients with metastatic breast cancer (mBC) after progression on ≥1 human epidermal growth factor receptor 2 (HER2)-targeted therapies. However, interstitial lung disease (ILD) and cardiotoxicity are the most significant toxicities associated with T-DXd. Therefore, we conducted a systematic review and meta-analysis to assess the incidence and severity of these toxicities in mBC patients treated with T-DXd.

MATERIALS AND METHODS

We searched PubMed, Cochrane, and Scopus databases, and conferences websites for randomized clinical trials and nonrandomized studies of intervention including HER2-low or HER2-positive mBC patients who received at least one dose of T-DXd. Statistical analysis was carried out using R software.

RESULTS

We included 15 studies comprising 1970 patients with a mean follow-up of 13.3 months. Median age ranged from 53 to 59 years, 61.9% were non-Asian, and 67.4% had hormone receptor-positive mBC. In a pooled analysis, the incidence of ILD was 11.7% [222 patients; 95% confidence interval (CI) 9.1% to 15.0%]. Patients receiving T-DXd dose of 6.4 mg/kg developed a significantly higher rate of ILD (22.7%) compared to those receiving a dose of 5.4 mg/kg (9.3%) (P < 0.01). Most cases of ILD (80.2%; 174/217 patients) were mild (grade 1 or 2). Grade 3 or 4 ILD was reported in 29 patients (13.4%), and grade 5 in 14 patients (6.4%). The incidence of decreased left ventricular ejection fraction (LVEF) was 1.95% (95% CI 0.65% to 3.73%), and the QT interval (QTi) prolongation was 7.77% (95% CI 2.74% to 20.11%). Most patients were asymptomatic, but four had LV dysfunction and heart failure (0.26%).

CONCLUSIONS

In this meta-analysis of 1970 patients with mBC, treatment with T-DXd was associated with a 11.7% incidence of ILD, 7.7% incidence of prolonged QTi, and 1.9% incidence of reduced LVEF. Early detection and management of T-DXd-related toxicity by a multidisciplinary team may ultimately improve patient outcomes.