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Poster Discussion - Breast cancer, metastatic

2713 - Leuprorelin (LEUP) combined with Letrozole (LET) with/without Everolimus (EVE) in Ovarian suppressed premenopausal women with hormone receptor (HR) positive, HER2-negative metastatic breast cancer (MBC): Primary analysis of LEO Trial (NCT02344550)


29 Sep 2019


Poster Discussion - Breast cancer, metastatic


Jaeho Jeong


Annals of Oncology (2019) 30 (suppl_5): v104-v142. 10.1093/annonc/mdz242


J. Jeong1, J.E. Kim2, J. Ahn1, K.H. Jung2, S. Koh3, J. Cheon3, J. Sohn4, G.M. Kim4, K.S. Lee5, I.H. Park5, S.H. Sim5, S. Kim2

Author affiliations

  • 1 Department Of Oncology, Asan Medical Center, University of Ulsan College of Medicine, 138-931 - Seoul/KR
  • 2 Department Of Oncology, Asan Medical Center, University of Ulsan College of Medicine, 05505 - Seoul/KR
  • 3 Division Of Hematology And Oncology, Ulsan University Hospital, 44033 - Ulsan/KR
  • 4 Medical Oncology, Yonsei Cancer Center Yonsei University, 120-752 - Seoul/KR
  • 5 Center For Breast Cancer, National Cancer Center, 10408 - Goyang-Si/KR


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Abstract 2713


Premenopausal women with MBC have a distinct tumor biology, and more aggressive behavior. In the BOLERO-2 trial, adding EVE to exemestane (EXE) significantly prolonged progression-free survival (PFS) compared with EXE alone in postmenopausal women with recurrent/metastatic HR+, HER2– breast cancer. LEO is the first randomized phase II trial investigating the effect of adding EVE to LET in ovarian suppressed premenopausal women with MBC.


Patients (pts) with progression or prior exposed to tamoxifen with or without GnRH agonist, either sequentially or concurrently, in adjuvant or metastatic setting were randomly assigned (2:1) to receive LEUP+LET+EVE (arm A) or LEUP+LET (arm B) until disease progression or unacceptable toxicity. Randomization was stratified by the presence of visceral metastases and sensitivity to endocrine therapy. The primary end point was PFS. Secondary end points included overall survival (OS), objective response rate (ORR), and safety.


Between January 2014 and October 2018, 137 pts were enrolled in this study. Baseline characteristics were well balanced between the two groups. The median age was 44 years (range 24-54), 74.5% had endocrine-sensitive disease, and 60.6% had visceral metastasis. At a median follow-up of 32.4 months, the median PFS was 18.1 months in arm A and 13.8 months in arm B, respectively (HR 0.73; 95% CI, 0.48 to 1.11; P = 0.137), and predominant in pts with visceral metastases (16.4 vs. 9.5 Mo) (HR 0.58; 95% CI, 0.34 to 0.99; p = 0.048). The median OS was not reached in both arms. ORR was 46.9% and 28.2% in arms A and B, respectively (P = 0.051). The most common grade 3/4 adverse events were neutropenia (9.8% in arm A vs. 0% in arm B), AST elevation (5.4% vs. 0%), enterocolitis (4.3% vs. 0%), and anemia (3.3% vs. 0%), without grade 3/4 stomatitis in both arms. Five pts discontinued treatment (1 AKI, 1 pneumonitis, 1 liver dysfunction, 2 unknown) but no treatment related death.


Adding EVE to LET demonstrated numerically improved PFS (D 4.3 Mo, median PFS), higher ORR. Significant improved PFS was noted in patients with visceral metastases.

Clinical trial identification


Editorial acknowledgement

Legal entity responsible for the study

Sung-Bae Kim.


Novartis, Dongkook Pharma Co. Ltd.


All authors have declared no conflicts of interest.

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