In vivo inhibition of aromatization by exemestane, a novel irreversible aromatase inhibitor, in postmenopausal breast cancer patients.
Clin Cancer Res
; 4(9): 2089-93, 1998 Sep.
Article
em En
| MEDLINE
| ID: mdl-9748124
ABSTRACT
The effect of exemestane (6-methylenandrosta-1,4-diene-3,17-dione) 25 mg p.o. once daily on in vivo aromatization was studied in 10 postmenopausal women with advanced breast cancer. Aromatization was determined before treatment and after 6-8 weeks on therapy by administering a bolus injection of [3H]androstenedione (500 microCi) and [14C]estrone (5 microCi) followed by measurement of the isotope ratio of urinary estrogens after high-performance liquid chromatography purification. In addition, plasma endogenous estrogens were measured with highly sensitive radioimmunoassays after separation with high-performance liquid chromatography. Treatment with exemestane suppressed whole body aromatization from a mean pretreatment value of 2.059% to 0.042% (mean suppression of 97.9%). Plasma levels of estrone, estradiol, and estrone sulfate were found to be suppressed by 94.5%, 92.2%, and 93.2%, respectively. This is the first study revealing near total aromatase inhibition in vivo with the use of a steroidal aromatase inhibitor. The observation that exemestane is a highly potent aromatase inhibitor, together with the fact that the drug is administered p.o. and causes limited side effects, suggests that exemestane is a promising new drug for the treatment of hormone sensitive breast cancer.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Neoplasias da Mama
/
Inibidores da Aromatase
/
Androstadienos
/
Antineoplásicos
Tipo de estudo:
Clinical_trials
Limite:
Female
/
Humans
Idioma:
En
Revista:
Clin Cancer Res
Assunto da revista:
NEOPLASIAS
Ano de publicação:
1998
Tipo de documento:
Article
País de afiliação:
Noruega