KEY TAKEAWAYS
- The study aimed to assess the benefits of using T-DM1 in addition to ET in pts with HER2+/HR+ MBC.
- The primary endpoint was to determine PFS.
- The combination of T-DM1 & ET improved outcomes in HER2+/HR+ MBC; prior pertuzumab may reduce efficacy.
Patients (pts) with human epidermal growth factor receptor 2-positive (HER2+), hormone receptor-positive (HR+) metastatic breast cancer (MBC) typically receive trastuzumab emtansine (T-DM1) therapy in subsequent lines of treatment. Combining endocrine therapy (ET) with T-DM1 may enhance treatment outcomes for this subtype.
Oğuzcan Kınıkoğlu and the team designed this study to investigate the benefits of using T-DM1 + ET in HER2+ and HR+ (HER2+/HR+) MBC. It was the 1 breakthrough unveiling the benefits of this comninatorial therapy.
Researchers analyzed the medical records of pts with HER2+/HR+ MBC who were being treated with T-DM1 from June 2010 to December 2021. The pts were stratified into groups on the basis of concomitant ET received along with T-DM1. The primary endpoint was to evaluate progression-free survival (PFS) and the secondary endpoints of the analysis were to calculate overall survival (OS), objective response rate (ORR), and safety of the treatment.
Results indicated that the analysis of 88 pts, of whom 32 (36.4%) were treated with T-DM1 in combination with ET. The combination of this therapy demonstrated a statistically significant inlcine in median PFS (15.4 vs 6.4 months; P = 0.00004) and median OS (35.0 vs 23.1 months; P = 0.026) vs T-DM1 alone. The ORR was also higher in the combination group (65.6% vs 29.3%; P = 0.026).
Patients receiving prior treatment with pertuzumab demonstrated a reduced median PFS with T-DM1vs those not recieving prior pertuzumab (11.7 vs 5.4 months, respectively; P < 0.01). T-DM1 demonstrated better median PFS in HER2 3+ pts compared to HER2+ pts with an amplification ratio of >2.0 (10.8 vs 5.8 months, respectively; P = 0.049). The safety profiles were manageable and concurrent with already established T-DM1 studies.
The study concluded that combining T-DM1 with ET significantly enhances PFS and OS in HER2-positive, HR-positive MBC. Additionally, pre-treatment with pertuzumab + trastuzumab may reduce the efficacy of T-DM1.
The study did not receive any external funding.
Source: https://pubmed.ncbi.nlm.nih.gov/38929568/
Kınıkoğlu O., Odabas H., Altıntaş Y. E., et al. (2024). “Combining Endocrine Therapy with Trastuzumab Emtansine Improves Progression-Free Survival and Overall Survival in HER2-Positive, Hormone Receptor-Positive Metastatic Breast Cancer.” Medicina (Kaunas). 2024 Jun 7;60(6):951. doi: 10.3390/medicina60060951. PMID: 38929568.
