Letrozole, a new oral non-steroidal aromastase inhibitor in treating postmenopausal patients with advanced breast cancer. A pilot study

G. Bisagni, G. Cocconi, F. Scaglione, F. Fraschini, Ch Pfister, P. F. Trunet

Research output: Contribution to journalArticle

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Abstract

Purpose: To evaluate the endocrine effects as well as the pharmacokinetic parameters, efficacy and safety of letrozole, a new fourth-generation non-steroidal aromatase inhibitor. Patients and methods: Fourteen postmenopausal women with progressive metastatic breast cancer, previously treated with endocrine therapy and/or chemotherapy for advanced disease, were treated with 0.5 mg daily doses of letrozole, orally. Endocrine and pharmacokinetic measurements were made before treatment and on days 14, 28, 56, and 84 of therapy. Results: Letrozole induced a >86% decrease in plasma estrone and a ~ 67% reduction in circulating estradiol from day 14 on. There was a statistically significant decrease in plasma cortisol, which appeared clinically irrelevant since all values remained within the normal range. No significant changes in aldosterone concentration were noted. One patient achieved a complete response (CR) and 4 patients a partial response (PR), with an objective response rate of 36% (95% CI 13% to 65%). Median duration of response was 24 months, ranging from 4 to 44 months. No toxic effects attributable to letrozole were noted in any patient. Conclusion: Letrozole appears to be a very promising new antiaromatase drug. The characteristics of the patients more likely to respond, taking into account prior systemic treatment, should be defined by future studies. Further phase II and phase III studies comparing letrozole to other available second or even first-line endocrine-therapy agents, are warranted.

Original languageEnglish
Pages (from-to)99-102
Number of pages4
JournalAnnals of Oncology
Volume7
Issue number1
Publication statusPublished - Jan 1996

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letrozole
Breast Neoplasms
Pharmacokinetics
Therapeutics
Aromatase Inhibitors
Estrone
Poisons
Aldosterone
Hydrocortisone
Estradiol
Reference Values

Keywords

  • Aromatase inhibitors
  • Breast carcinoma
  • Endocrine therapy
  • Letrozole

ASJC Scopus subject areas

  • Oncology
  • Cancer Research

Cite this

Letrozole, a new oral non-steroidal aromastase inhibitor in treating postmenopausal patients with advanced breast cancer. A pilot study. / Bisagni, G.; Cocconi, G.; Scaglione, F.; Fraschini, F.; Pfister, Ch; Trunet, P. F.

In: Annals of Oncology, Vol. 7, No. 1, 01.1996, p. 99-102.

Research output: Contribution to journalArticle

Bisagni, G. ; Cocconi, G. ; Scaglione, F. ; Fraschini, F. ; Pfister, Ch ; Trunet, P. F. / Letrozole, a new oral non-steroidal aromastase inhibitor in treating postmenopausal patients with advanced breast cancer. A pilot study. In: Annals of Oncology. 1996 ; Vol. 7, No. 1. pp. 99-102.
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