Combining Endocrine Therapy with Trastuzumab Emtansine Improves Progression-Free Survival and Overall Survival in HER2-Positive, Hormone Receptor-Positive Metastatic Breast Cancer

• Published in: Medicina (Kaunas, Lithuania) Vol. 60; no. 6; p. 951
• Main Authors: Kınıkoğlu, Oğuzcan, Odabas, Hatice, Altıntaş, Yunus Emre, Yıldız, Anıl, Çakan, Burçin, Akdağ, Goncagül, Yıldırım, Sedat, Bal, Hamit, Kaya, Tuğba, Tünbekici, Salih, Işık, Deniz, Başoğlu, Tuğba, Yıldırım, Mahmut Emre, Turan, Nedim
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 01.06.2024; MDPI
• Subjects: Ado-Trastuzumab Emtansine - therapeutic use; Adult; Aged; Aged, 80 and over; Antimitotic agents; Antineoplastic agents; Antineoplastic Agents, Immunological - pharmacology; Antineoplastic Agents, Immunological - therapeutic use; Antineoplastic Combined Chemotherapy Protocols - pharmacology; Antineoplastic Combined Chemotherapy Protocols - therapeutic use; Breast cancer; Breast Neoplasms - drug therapy; Breast Neoplasms - mortality; Cancer; Chemotherapy; Cytotoxicity; Development and progression; Endocrine therapy; Estrogens; Female; Hormones; Humans; Medical records; Metastasis; metastatic breast cancer; Middle Aged; Multivariate analysis; Neoplasm Metastasis; Patient outcomes; Patients; pertuzumab plus trastuzumab; Progression-Free Survival; Receptor, ErbB-2 - analysis; Receptors, Estrogen - analysis; Receptors, Estrogen - metabolism; Retrospective Studies; Statistical analysis; Survival analysis; Trastuzumab - therapeutic use; trastuzumab emtansine; Tumors; trastuzumab emtansine; metastatic breast cancer; endocrine therapy; pertuzumab plus trastuzumab
• ISSN: 1648-9144; 1010-660X; 1648-9144
• DOI: 10.3390/medicina60060951

Patients with human epidermal growth factor receptor 2 (HER2) -positive, hormone receptor-positive (HR-positive) metastatic breast cancer (MBC) usually undergo trastuzumab emtansine (T-DM1) therapy in subsequent lines. Combining endocrine therapy (ET) with T-DM1 can improve treatment outcomes in this subtype. Therefore, this study aimed to investigate the benefits of using T-DM1 with ET in HER2-positive and HR-positive MBC. This study was the first to investigate the benefits of combining ET with T-DM1. This study analyzed the medical records of patients with HER2-positive and HR-positive MBC who were treated with T-DM1 from June 2010 to December 2021. The patients were divided into groups based on whether they received concomitant ET with T-DM1. The primary endpoint was to determine the progression-free survival (PFS), while the secondary endpoints were overall survival (OS), objective response rate, and safety of the treatment. Our analysis examined 88 patients, of whom 32 (36.4%) were treated with T-DM1 in combination with ET. The combination therapy showed a significant improvement in median PFS (15.4 vs. 6.4 months; = 0.00004) and median OS (35.0 vs. 23.1 months; = 0.026) compared to T-DM1 alone. The ORR was also higher in the combination group (65.6% vs. 29.3%; = 0.026). Patients treated with pertuzumab priorly had reduced median PFS on T-DM1 compared to those who were not treated with pertuzumab (11.7 vs. 5.4 months, respectively; < 0.01). T-DM1 demonstrated better median PFS in HER2 3+ patients compared to HER2 2+ patients, with an amplification ratio of >2.0 (10.8 vs 5.8 months, respectively; = 0.049). The safety profiles were consistent with previous T-DM1 studies. The combination of T-DM1 with ET can significantly improve PFS and OS in patients with HER2-positive and HR-positive MBC. Our study suggests that prior pertuzumab treatment plus trastuzumab treatment might decrease T-DM1 efficacy.