Cnsc-62. Differential Survival Impact of Trastuzumab Deruxtecan in Her2-positive Versus Her2-low Breast Cancer Patients With Brain Metastases
Year: 2024
Type: conference-abstract
Abstract: BACKGROUND Brain metastases (BM) in breast cancer (BC) present significant treatment challenges, with varying outcomes based on HER2 expression. There is limited real-world evidence of outcomes with the use of trastuzumab deruxtecan (T-DXd) on survival in patients (pts) with HER2-low and HER2-positive (HER2+) MBC with BM. METHODS We conducted a retrospective cohort study using data from seven US-based health systems within the Guardian Research Network (GRN). We included pts treated with T-DXd from December 2019 to December 2023, classified as HER2-low (IHC 1+ or IHC 2+/HER2 FISH non-amplified) or HER2+ (IHC 3+ or HER2+ with FISH amplified). Survival analysis was performed using Kaplan-Meier curves and the log-rank test. RESULTS 125 pts with BCBM treated with T-DXd were included in the final analysis, of which 70 (56%) were HER2+ and 55 (44%) were HER2-low. The median age at BM diagnosis was 60.5 years (range 21.6 to 87.1 years). HER2 low pts had a higher prevalence of ER+ disease than HER2+ pts (81.9% vs. 55.7%, p=0.01). Most of these pts (≥75%) had received multiple prior lines of therapy. HER2+ pts with BM had a median overall survival (mOS) of 9.3 months (95% CI: 6.79-11.88), significantly longer than 4.3 months (95% CI: 1.89-6.82) in HER2-low pts (p < 0.001). At 6 months, OS for HER2+ pts with BM was 40% compared to 25% in HER2-low pts. At 12 months, OS for HER2+ pts was 20% compared to 10% in HER2-low pts. CONCLUSIONS This study represents the largest real-world evidence to date on the effectiveness of T-DXd in treating BM from breast cancer. HER2+ BCBM exhibited longer mOS and 12-month survival rates than pts with HER2-low disease, suggesting HER2 expression is crucial in determining T-DXd’s effectiveness. Future research should explore combination therapies and identify predictive biomarkers to optimize treatment strategies through clinical trials.
Source: Neuro-Oncology
Institution: Baptist Health South Florida
Language: English
Subfield: Pulmonary and Respiratory Medicine
Field: Medicine
Domain: Health Sciences
Open Access status: bronze
OpenAlex ID: W4404237432