ATAMESTANE

Possibly Marketed Outside US

Details

Stereochemistry	ABSOLUTE
Molecular Formula	C20H26O2
Molecular Weight	298.4192
Optical Activity	UNSPECIFIED
Defined Stereocenters	5 / 5
E/Z Centers	0
Charge	0

SHOW SMILES / InChI

Structure Search

SMILES

CC1=CC(=O)C=C2CC[C@H]3[C@@H]4CCC(=O)[C@@]4(C)CC[C@@H]3[C@@]12C

InChI

InChIKey=PEPMWUSGRKINHX-TXTPUJOMSA-N

InChI=1S/C20H26O2/c1-12-10-14(21)11-13-4-5-15-16-6-7-18(22)19(16,2)9-8-17(15)20(12,13)3/h10-11,15-17H,4-9H2,1-3H3/t15-,16-,17-,19-,20-/m0/s1

HIDE SMILES / InChI

Molecular Formula	C20H26O2
Molecular Weight	298.4192
Charge	0
Count

Stereochemistry	ABSOLUTE
Additional Stereochemistry	No
Defined Stereocenters	5 / 5
E/Z Centers	0
Optical Activity	UNSPECIFIED

Description
Sources: https://www.ncbi.nlm.nih.gov/pubmed/17971594 | http://adisinsight.springer.com/drugs/800002517 | https://www.ncbi.nlm.nih.gov/pubmed/1722797 | https://www.ncbi.nlm.nih.gov/pubmed/7682838

Atamestane is a new, competitive, and irreversible inhibitor of estrogen biosynthesis. It is an aromatase inhibitor. Atamestane lacks other intrinsic hormonal or antihormonal activities and shows no inhibition of other cytochrome-P450 dependent enzymes of adrenal steroidogenesis. It had been in phase III clinical trial for the treatment of breast cancer and phase II for the treatment of benign prostatic hyperplasia. It was discontinued from development after an 865-patient trial in breast cancer showed no improvement in efficacy over letrozole.

Originator

Approval Year

Targets

Primary Target	Pharmacology	Condition	Potency
Aromatase 8 Target ID: P11511 Gene ID: 1588.0 Gene Symbol: CYP19A1 Target Organism: Homo sapiens (Human) Sources: https://www.ncbi.nlm.nih.gov/pubmed/7682838	Inhibitor 8504		0.4 µM [EC50]

Conditions

Condition	Modality	Highest Phase	Product
Breast cancer 432 Sources: https://www.ncbi.nlm.nih.gov/pubmed/17971594	Primary	Phase III 665	Unknown Approved Use Unknown
Benign prostatic hyperplasia 28 Sources: https://www.ncbi.nlm.nih.gov/pubmed/7545721 https://www.ncbi.nlm.nih.gov/pubmed/7541854	Primary	Phase II 1147	Unknown Approved Use Unknown
Physical frailty 1 Sources: https://www.ncbi.nlm.nih.gov/pubmed/16804050 http://www.ergo-log.com/dheaplusatamestane.html	Primary	Phase II 1147	Unknown Approved Use Unknown

Doses

Dose	Population	Adverse events
300 mg 1 times / day steady, oral Highest studied dose\|Studied dose Dose: 300 mg, 1 times / day Route: oral Route: steady Dose: 300 mg, 1 times / day Sources: https://pubmed.ncbi.nlm.nih.gov/8876703/	unhealthy, ADULT Health Status: unhealthy Age Group: ADULT Sex: M Food Status: UNKNOWN Sources: https://pubmed.ncbi.nlm.nih.gov/8876703/	Disc. AE: Dizziness, Allergic reaction... AEs leading to discontinuation/dose reduction: Dizziness (1%) Allergic reaction (2%) Nervous system dis (4.9%) Headache (7.8%) Sources: https://pubmed.ncbi.nlm.nih.gov/8876703/
500 mg steady, oral Highest studied dose\|Studied dose Dose: 500 mg Route: oral Route: steady Dose: 500 mg Sources: https://pubmed.ncbi.nlm.nih.gov/17971594/	unhealthy, ADULT Health Status: unhealthy Age Group: ADULT Sex: F Food Status: UNKNOWN Sources: https://pubmed.ncbi.nlm.nih.gov/17971594/	Other AEs: Asthenia, Weight increased... Other AEs: Asthenia (11%) Weight increased (12%) Hot flush (10%) Sources: https://pubmed.ncbi.nlm.nih.gov/17971594/

AEs

AE	Significance	Dose	Population
Dizziness	1% Disc. AE	300 mg 1 times / day steady, oral Highest studied dose\|Studied dose Dose: 300 mg, 1 times / day Route: oral Route: steady Dose: 300 mg, 1 times / day Sources: https://pubmed.ncbi.nlm.nih.gov/8876703/	unhealthy, ADULT Health Status: unhealthy Age Group: ADULT Sex: M Food Status: UNKNOWN Sources: https://pubmed.ncbi.nlm.nih.gov/8876703/
Allergic reaction	2% Disc. AE	300 mg 1 times / day steady, oral Highest studied dose\|Studied dose Dose: 300 mg, 1 times / day Route: oral Route: steady Dose: 300 mg, 1 times / day Sources: https://pubmed.ncbi.nlm.nih.gov/8876703/	unhealthy, ADULT Health Status: unhealthy Age Group: ADULT Sex: M Food Status: UNKNOWN Sources: https://pubmed.ncbi.nlm.nih.gov/8876703/
Nervous system dis	4.9% Disc. AE	300 mg 1 times / day steady, oral Highest studied dose\|Studied dose Dose: 300 mg, 1 times / day Route: oral Route: steady Dose: 300 mg, 1 times / day Sources: https://pubmed.ncbi.nlm.nih.gov/8876703/	unhealthy, ADULT Health Status: unhealthy Age Group: ADULT Sex: M Food Status: UNKNOWN Sources: https://pubmed.ncbi.nlm.nih.gov/8876703/
Headache	7.8% Disc. AE	300 mg 1 times / day steady, oral Highest studied dose\|Studied dose Dose: 300 mg, 1 times / day Route: oral Route: steady Dose: 300 mg, 1 times / day Sources: https://pubmed.ncbi.nlm.nih.gov/8876703/	unhealthy, ADULT Health Status: unhealthy Age Group: ADULT Sex: M Food Status: UNKNOWN Sources: https://pubmed.ncbi.nlm.nih.gov/8876703/
Hot flush	10%	500 mg steady, oral Highest studied dose\|Studied dose Dose: 500 mg Route: oral Route: steady Dose: 500 mg Sources: https://pubmed.ncbi.nlm.nih.gov/17971594/	unhealthy, ADULT Health Status: unhealthy Age Group: ADULT Sex: F Food Status: UNKNOWN Sources: https://pubmed.ncbi.nlm.nih.gov/17971594/
Asthenia	11%	500 mg steady, oral Highest studied dose\|Studied dose Dose: 500 mg Route: oral Route: steady Dose: 500 mg Sources: https://pubmed.ncbi.nlm.nih.gov/17971594/	unhealthy, ADULT Health Status: unhealthy Age Group: ADULT Sex: F Food Status: UNKNOWN Sources: https://pubmed.ncbi.nlm.nih.gov/17971594/
Weight increased	12%	500 mg steady, oral Highest studied dose\|Studied dose Dose: 500 mg Route: oral Route: steady Dose: 500 mg Sources: https://pubmed.ncbi.nlm.nih.gov/17971594/	unhealthy, ADULT Health Status: unhealthy Age Group: ADULT Sex: F Food Status: UNKNOWN Sources: https://pubmed.ncbi.nlm.nih.gov/17971594/

Overview

CYP3A4	CYP2C9	CYP2D6	hERG

OverviewOther

Other Inhibitor	Other Substrate	Other Inducer
CYP19A1 429

Drug as perpetrator

Target	Modality	Activity	Metabolite	Clinical evidence
CYP19A1 430	inhibitor 4027 Sources: https://pubmed.ncbi.nlm.nih.gov/10443682/	yes [IC50 0.0304 uM]

PubMed

Title	Date	PubMed
Comparing the effects of atamestane, toremifene and tamoxifen alone and in combination, on bone, serum lipids and uterus in ovariectomized rats.	2009-02	19429427
Toremifene-atamestane; alone or in combination: predictions from the preclinical intratumoral aromatase model.	2008-01	17942301
Phase III, double-blind, controlled trial of atamestane plus toremifene compared with letrozole in postmenopausal women with advanced receptor-positive breast cancer.	2007-11-01	17971594
An alpha-fetoprotein-derived peptide reduces the uterine hyperplasia and increases the antitumour effect of tamoxifen.	2007-08-06	17637684
Superiority of gas chromatography/tandem mass spectrometry assay (GC/MS/MS) for estradiol for monitoring of aromatase inhibitor therapy.	2007-07	17588628
The effects of atamestane and toremifene alone and in combination compared with letrozole on bone, serum lipids and the uterus in an ovariectomized rat model.	2007-07	17063268
Effects of dehydroepiandrosterone and atamestane supplementation on frailty in elderly men.	2006-10	16804050

Patents

Sample Use Guides

In Vivo Use Guide

Atamestane is administered over 48 weeks as a daily dose of 100 mg or 300 mg.

Route of Administration: Oral

In Vitro Use Guide

The levels of aromatase mRNA was 6.31 amol/ug total RNA in JEG-3 cells, cultured in the presence or absence of 10 uM Atamestane at 37°C for 24 h.

Substance Class	Chemical Created by `admin` on `Wed Apr 02 08:21:13 GMT 2025` Edited by `admin` on `Wed Apr 02 08:21:13 GMT 2025`
Record UNII	62GA3K28B6
Record Status	`Validated (UNII)`
Record Version

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Name

Type

Language

atamestane [INN]

Preferred Name

English

ATAMESTANE

Official Name

English

SH-489

Code

English

1-METHYLANDROSTA-1,4-DIENE-3,17-DIONE

Systematic Name

English

Atamestane [WHO-DD]

Common Name

English

Classification Tree Code System Code

NCI_THESAURUS

C2017