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Exemestane versus anastrozole as front‐line endocrine therapy in postmenopausal patients with hormone receptor‐positive, advanced breast cancer
Author(s) -
LlombartCussac Antonio,
Ruiz Amparo,
Antón Antonio,
Barnadas Agustí,
Antolín Silvia,
AlésMartínez José E.,
Álvarez Isabel,
Andrés Raquel,
García Saenz José A.,
Lao Juan,
Carrasco Eva,
Cámara Carmen,
Casas Isabel,
Martín Miguel
Publication year - 2011
Publication title -
cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.052
H-Index - 304
eISSN - 1097-0142
pISSN - 0008-543X
DOI - 10.1002/cncr.26299
Subject(s) - exemestane , anastrozole , medicine , aromatase inhibitor , breast cancer , tamoxifen , oncology , clinical endpoint , metastatic breast cancer , aromatase , cancer , gynecology , clinical trial
BACKGROUND: Several aromatase inhibitor studies have reported variations in the inhibitory potency of these agents that could lead to differences in clinical outcomes. In the current study, the authors formally evaluated the activity of anastrozole and exemestane in postmenopausal women with hormone‐responsive, advanced breast cancer. METHODS: Postmenopausal women who had measurable disease according to Response Evaluation Criteria in Solid Tumors and had not received previous endocrine therapy for advanced breast cancer were randomized to receive either oral exemestane 25 mg daily or oral anastrozole 1 mg daily until they had disease progression. The primary endpoint was the objective response rate (ORR), and secondary endpoints included the clinical benefit rate (CBR), time to progression (TTP), overall survival, and safety. Crossover to the other aromatase inhibitor was permitted at the time of disease progression; ORR, CBR, and TTP after second‐line treatment also were explored. RESULTS: In total, 103 patients were enrolled. The median patient age was 71.6 years, 52.4% of patients had visceral disease, and 75.8% of patients had ≥2 disease sites. Half of the patients had received previous tamoxifen, and 60% had received previous chemotherapy. The efficacy observed in the exemestane and anastrozole groups was an ORR of 36.2% and 46%, respectively; a CBR of 59.6% and 68%, respectively, and a TTP of 6.1 months and 12.1 months, respectively. At progression, 28 patients crossed over to the other aromatase inhibitor, including 16 patients who switched to exemestane (CBR, 43.7%; TTP, 4.4 months) and 12 patients who switched to anastrozole (CBR, 8.3%; TTP, 2 months). Both drugs were generally well tolerated, and no study drug‐related serious adverse events were reported. CONCLUSIONS: In this phase 2 randomized trial, no significant differences in clinical activity were observed in favor of exemestane to justify a superiority phase 3 trial design in the first‐line setting. Cancer 2012;. © 2011 American Cancer Society.