Site Editor
William J. Gradishar, MD, FACP, FASCO
William J. Gradishar, MD, FACP, FASCO
Posted: Monday, June 3, 2024
Giuseppe Curigliano, MD, PhD, of the University of Milan and European Institute of Oncology, IRCCS, Italy, and colleagues compared the use of the antibody-drug conjugate trastuzumab deruxtecan (T-DXd) and chemotherapy in patients with hormone receptor (HR)-positive, HER2-low, metastatic breast cancer who underwent prior endocrine therapy. Presented during the 2024 American Society of Clinical Oncology (ASCO) Annual Meeting (Abstract LBA1000), the results of the DESTINY-Breast06 trial revealed no new safety signals.
“T-DXd showed a statistically significant and clinically meaningful progression-free survival benefit vs physician’s choice of chemotherapy in HER2-low metastatic breast cancer,” the investigators concluded. “DESTINY-Breast06 establishes T-DXd as a standard of care following at least one endocrine-based therapy for patients with HER2-low and -ultralow, HR-positive metastatic breast cancer.”
A total of 866 patients with HER2-low (n = 713) or -ultralow, (n = 153) HR-positive, metastatic breast cancer were randomly assigned 1:1 to receive T-DXd at 5.4 mg/kg or chemotherapy. Prior chemotherapy was not allowed; however, participants were required to undergo at least one prior line of endocrine therapy. Endpoints included progression-free survival, overall survival, safety, and objective response rate.
Patients in the chemotherapy group received capecitabine (59.8%), nab-paclitaxel (24.4%), or paclitaxel (15.8%). The median duration of T-DXd and chemotherapy was 11.0 and 5.6 months, respectively. Among individuals with HER2-low disease, progression-free survival was significantly improved with T-DXd compared with chemotherapy (P < .0001); the intent-to-treat and HER2-ultralow populations experienced similar results.
At the first interim analysis, the median follow-up was 18.6 months; overall survival data remained immature.
Grade 3 or higher treatment-related adverse events were reported more frequently with T-DXd than with chemotherapy (40.6% vs 31.4%). Furthermore, interstitial lung disease/pneumonitis was more common among patients receiving T-DXd (n = 49) than those receiving chemotherapy (n = 1).
Disclosure: For full disclosures of the study authors, visit coi.asco.org.
JNCCN Spotlights
