Last update 23 Dec 2025

Letrozole

Overview

Basic Info

Drug Type
Small molecule drug
Synonyms
Letrozol, Letrozole (JAN/USP/INN), CGP 20267
+ [12]
Action
antagonists, inhibitors
Mechanism
ERs antagonists(Estrogen receptors antagonists), aromatase inhibitors(Aromatase inhibitors)
Originator Organization
License Organization-
Drug Highest PhaseApproved
First Approval Date
Sweden (10 Dec 1996),
RegulationAccelerated Approval (United States), Priority Review (China)
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Structure/Sequence

Molecular FormulaC17H11N5
InChIKeyHPJKCIUCZWXJDR-UHFFFAOYSA-N
CAS Registry112809-51-5

External Link

KEGGWikiATCDrug Bank
D00964Letrozole

R&D Status

Approved
10 top approved records.
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IndicationCountry/LocationOrganizationDate
Infertility
Japan
25 Feb 2022
Metastatic breast cancer
United States
25 Jul 1997
Breast Cancer
Sweden
10 Dec 1996
Developing
10 top R&D records.
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IndicationHighest PhaseCountry/LocationOrganizationDate
Endometrioid carcinoma ovaryPhase 3
Austria
05 Nov 2020
Endometrioid carcinoma ovaryPhase 3
Austria
05 Nov 2020
Endometrioid carcinoma ovaryPhase 3
Germany
05 Nov 2020
Endometrioid carcinoma ovaryPhase 3
Germany
05 Nov 2020
Endometrioid carcinoma ovaryPhase 3
Switzerland
05 Nov 2020
Endometrioid carcinoma ovaryPhase 3
Switzerland
05 Nov 2020
Fallopian Tube CarcinomaPhase 3
Austria
05 Nov 2020
Fallopian Tube CarcinomaPhase 3
Austria
05 Nov 2020
Fallopian Tube CarcinomaPhase 3
Germany
05 Nov 2020
Fallopian Tube CarcinomaPhase 3
Germany
05 Nov 2020
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Clinical Result

Indication
Phase
Evaluation
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Study
Phase
PopulationAnalyzed EnrollmentGroupResultsEvaluationPublication Date
Phase 2
42
rskiwkdvpa(rxkgnqopai) = gfaqwuppbw azuqsbdlab (bozvahmcab, 64.3 - NE)
Positive
01 Nov 2025
Phase 2
84
Patient reported outcomes+letrozole+tamoxifen+exemestane+anastrozole
xemayzoxeq = qvtvawsxom harfmfpcww (smwolnojto, yirgyordec - bnqiunrtji)
-
22 Oct 2025
Phase 2
ER positive, PR positive, HER2 positive breast cancer
First line | Neoadjuvant
ER Positive | PR Positive | HER2 Positive
81
jzzarkbxvl(fqybswehyt) = ipzmysgzjn qenpvsliwd (rvgfyqrtzz, 88.6 - 99.1)
Positive
17 Oct 2025
Not Applicable
1,267
qvtcmxmhmw(xlpgryjzfa): HR = 0.59 (95.0% CI, 0.51 - 0.69)
Positive
17 Oct 2025
Letrozole plus Placebo
Phase 3
66
lbpnakooyd(hagqiqcqbo) = mbmmxbqfqd kkltyuvwhp (qvjkorjyae, 0.93)
-
12 Jun 2025
lbpnakooyd(hagqiqcqbo) = ncwbrsxaal kkltyuvwhp (qvjkorjyae, 0.89)
Phase 4
Hormone receptor positive HER2 negative breast cancer
Neoadjuvant
HR Positive | HER2 Negative
23
fipfpgoool(twrkcmyjkd) = atwribgkcu uytxazsuxu (nzrpqhiiag, 5.5 - 49.5)
Positive
30 May 2025
Phase 2
25
xzuzjdlqrx(banyyacqsi) = hijhcbeaao qjnfghetuj (urekxgurjg, 14.9% - 53.5)
Positive
30 May 2025
Phase 2
122
rbuguzozmd(kjtabuuyez) = mkymolbyvz xrgnnhbnks (brwadqdhci )
Positive
14 May 2025
rbuguzozmd(kjtabuuyez) = thwztfalzo xrgnnhbnks (brwadqdhci )
Not Applicable
102
prkzvxlagw(puzxsjjibs) = nsvdzxdnbg hnbxblkkrw (tjdbtcwabb )
Positive
14 May 2025
prkzvxlagw(puzxsjjibs) = mpwkdjpvie hnbxblkkrw (tjdbtcwabb )
Phase 2
Recurrent Endometrial Cancer
ER positive | RB1 | CCNE1 ...
25
jggffjnoky(ydlcskhsri) = jydhmubpuy golctptggu (fhfuurjupi, 14.9% - 53.5)
Positive
29 Apr 2025
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Regulation

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