Phase I study of the oral nonsteroidal aromatase inhibitor CGS 20267 in healthy postmenopausal women

Iveson, T. J.

doi:10.1210/jc.77.2.324

Cited by 84Estrogen and related hormone effectsMenopause: Health Impacts and TreatmentsBreast Cancer Treatment Studies

Phase I study of the oral nonsteroidal aromatase inhibitor CGS 20267 in healthy postmenopausal women

Iveson, T. J.·1993·Journal of Clinical Endocrinology & Metabolism

DOI 10.1210/jc.77.2.324

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Abstract

We have performed a phase I study of the effect of a single dose of CGS 20267, an oral nonsteroidal aromatase inhibitor, in 12 healthy volunteer postmenopausal women. Each subject received 2 single doses of CGS 20267 (0.1, 0.5, or 2.5 mg) or placebo separated by a washout period of at least 6 weeks. There was statistically significant suppression of serum estrone and estradiol at all three doses of CGS 20267 tested. Serum estrone and estradiol concentrations were maximally suppressed by 76% and 79% from baseline levels, respectively. Urinary excretion of estrone and estradiol was also suppressed, although this did not reach statistical significance. Serum concentrations of aldosterone, cortisol, 17 alpha-hydroxyprogesterone, androstenedione, testosterone, FSH, LH, and TSH were unaffected by CGS 20267. The drug was well tolerated, with no significant side-effects. This study has shown CGS 20267 to be a potent and specific aromatase inhibitor, and further studies are now needed to assess its clinical efficacy.

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Aromatase inhibitors have a relatively short half-life compared with CC and therefore would be eliminated from the body rapidly.
“These aromatase inhibitors have a relatively short half-life compared with CC and therefore would be eliminated from the body rapidly (14,15).”
From Use of an aromatase inhibitor for induction of ovulation in patients with an inadequate response to clomiphene citrate (2001) · cites this paper as [15]
Continuous administration of letrozole up to 5 mg/d produced marked suppression of E2, estrone, and estrone sulfate, with very few side effects.
“Continuous administration of letrozole up to 5 mg/d produced marked suppression of E 2 , estrone, and estrone sulfate, with very few side effects (14,15).”
From Use of an aromatase inhibitor for induction of ovulation in patients with an inadequate response to clomiphene citrate (2001) · cites this paper as [15]

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Open dose-finding study of a new potent and selective nonsteroidal aromatase inhibitor, CGS 20 267, in healthy male subjects
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Authors: Iveson, T. J.
Affiliations: Royal Marsden Hospital (GB)
ORCID: Iveson, T. J.
Venue: Journal of Clinical Endocrinology & Metabolism
Publisher: The Endocrine Society
Published: 1993-08-01
Volume: 77
Issue: 2
Pages: 324-331
ISSN: 0021-972X (ISSN-L)
DOI: 10.1210/jc.77.2.324
OpenAlex: W2019170771
Cited by: 82
References: 27
Citations by year: 2025: 1 · 2024: 1 · 2020: 1 · 2019: 3 · 2018: 1 · 2017: 4 · 2016: 2 · 2015: 5 · 2014: 2 · 2013: 1 · 2012: 7
FWCI: 2.10
Type: journal article
Language: en
Open access: closed
Locations: The Journal of Clinical Endocrinology & Metabolism (publishedVersion)
PubMed (publishedVersion)
Topics: Life Sciences › Biochemistry, Genetics and Molecular Biology › Genetics › Estrogen and related hormone effects
Health Sciences › Medicine › Endocrinology, Diabetes and Metabolism › Menopause: Health Impacts and Treatments
Life Sciences › Biochemistry, Genetics and Molecular Biology › Cancer Research › Breast Cancer Treatment Studies
Keywords: nonsteroidal aromatase inhibitors, postmenopausal women, estradiol suppression, urinary excretion, dose-response relationship, drug tolerability, healthy volunteers
MeSH terms: Letrozole, Administration, Oral, Aged, Aldosterone, Androstenedione, Dose-Response Relationship, Drug, Estradiol, Estrone, Female, Follicle Stimulating Hormone, Humans, Hydrocortisone, Hydroxyprogesterones, Luteinizing Hormone, Male, Menopause, Middle Aged, Nitriles, Random Allocation, Testosterone, Thyrotropin, Time Factors, Triazoles, 17-alpha-Hydroxyprogesterone, Aromatase Inhibitors

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Phase I study of the oral nonsteroidal aromatase inhibitor CGS 20267 in healthy postmenopausal women

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