Formestane: Effective therapy in postmenopausal women with advanced breast cancer

E. Bajetta, N. Zilembo, R. Buzzoni, C. Noberasco, A. Martinetti, L. Ferrari, C. Bartoli, V. Sacchini, A. Attili, P. Lepera

Research output: Contribution to journalArticlepeer-review


Aromatase inhibitors are a useful therapeutic option in the management of endocrine-dependent advanced breast cancer. Formestane (Lentaron®) is the first irreversible aromatase inhibitor to be extensively investigated. In a phase II study to determine the effects of formestane on serum estradiol and urinary 17-hydroxycorticosteroid (17-OHCS) levels and to evaluate its clinical activity, 72 postmenopausal. patients with advanced breast cancer were given formestane 250 mg intramuscularly every 2 weeks. Of 66 patients fully evaluable, 56 were estrogen receptor (ER) positive, and 43 had a disease-free interval ≥ 2 years. Metastases were assessable in soft tissue (53%), bone (53%) and viscera (47%); 34 patients had 1, 32 had ≥ 2 metastatic lesions. Serum estradiol levels fell significantly (p <0.01) after 2 weeks and remained unchanged thereafter, whereas urinary 17-OHCS levels did not change during treatment. Objective responses were obtained in 19 patients (29%), of whom 8 had complete response. In relation to disease sites, similar responses were obtained in soft tissue (33%) and viscera (30%), whereas response in bone was 18%. The overall tolerability of formestane was satisfactory, and only two patients complained of local side effects. We conclude that formestane is an effective aromatase inhibitor in postmenopausal patients with hormone-dependent breast cancer, and does not interfere with adrenal steroidogenesis.

Original languageEnglish
Pages (from-to)15-17
Number of pages3
JournalAnnals of Oncology
Issue numberSUPPL. 7
Publication statusPublished - 1994


  • Aromatase inhibition
  • Endocrine therapy
  • Formestane
  • Lentaron®
  • Postmenopausal breast cancer

ASJC Scopus subject areas

  • Oncology
  • Cancer Research

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