Rechallenge of Trastuzumab-based Therapy in HER2-Positive Breast Cancer Patients who Progressed Under TDM-1

• Published in: Indian journal of surgical oncology 2024-09, Vol.15 (3), p.484-488
• Main Authors: Dogan, Izzet, Ahmed, Melin Aydan, Yıldız, Anıl, Vatansever, Sezai
• Format: Article
• Language: English
• Subjects: Breast cancer; Chemotherapy; Medicine; Medicine & Public Health; Metastasis; Oncology; Original Article; Surgery; Surgical Oncology; Toxicity
• ISSN: 0975-7651; 0976-6952
• DOI: 10.1007/s13193-024-01935-9

Data on rechallenges of HER2 targetted agents in breast cancer patients is limited. The goal of the study was to evaluate the effectiveness of trastuzumab-based therapy in patients who progressed under trastuzumab emtansine (TDM-1). The study was designed as a retrospective observational study. Survival plots were performed with the Kaplan–Meier method. Fifteen patients were involved in the study. The average age was 45 (range, 30–66). De novo metastatic patient number was six (40%), and the average number of metastatic sites was 2 (range, 1–4) at diagnosis. Fourteen patients (92.3%) had undergone breast surgery (lumpectomy or mastectomy). All patients previously had been treated with trastuzumab-based chemotherapy and TDM-1. Also, nine (60%) patients had received endocrine therapy, and nine (60%) patients had palliative radiotherapy. After progression under TDM-1, patients received trastuzumab with chemotherapy (73.3%) or alone (26.7%). The overall response ratio was 66.7%. Median progression-free survival was 9.4 months (95% CI, 3.4–15.3). The median OS duration was 24.2 (95% CI, 13.5–34.9) months. Toxicity in all grades was observed in ten (66.7%) patients, and grade 3–4 toxicity (anemia and neutropenia) in two patients (13.3%). This study showed that rechallenge trastuzumab-based therapy was effective and good-tolerated in heavily pretreated patients who had progressed under TDM-1.