letrozole 🐶 Veterinary Use | Indications/Contra | FAERs-F | FAERs-M | Orange Bk | BioActivity |

Stem definition	Drug id	CAS RN
aromatase inhibitors, imidazole-triazole derivatives	1556	112809-51-5

Description:

Molecule	Description
Molfile Inchi Smiles Synonyms: CGS-20267 CGS 20267 letrozole lerozole letrazole femara	Letrozole is a nonsteroidal competitive inhibitor of the aromatase enzyme system; it inhibits the conversion of androgens to estrogens. Used in treatment of hormonally responsive breast cancer (i.e., estrogen and/or progesterone receptor positive or receptor unknown) Molecular weight: 285.31 Formula: C17H11N5 CLOGP: 1.70 LIPINSKI: 0 HAC: 5 HDO: 0 TPSA: 78.29 ALOGS: -3.55 ROTB: 3 Status: OFP Legend: OFP - off patent OFM - off market ONP - on patent

Molecule

Description

Molfile Inchi Smiles

Synonyms:

CGS-20267
CGS 20267
letrozole
lerozole
letrazole
femara

Letrozole is a nonsteroidal competitive inhibitor of the aromatase enzyme system; it inhibits the conversion of androgens to estrogens. Used in treatment of hormonally responsive breast cancer (i.e., estrogen and/or progesterone receptor positive or receptor unknown)

Molecular weight: 285.31
Formula: C17H11N5
CLOGP: 1.70
LIPINSKI: 0
HAC: 5
HDO: 0
TPSA: 78.29
ALOGS: -3.55
ROTB: 3

Status: OFP

Legend:
OFP - off patent
OFM - off market
ONP - on patent

Drug dosage:

Dose	Unit	Route
2.50	mg	O

ADMET properties:

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Property	Value	Reference
BA (Bioavailability)	99 %	Kim MT, Sedykh A, Chakravarti SK, Saiakhov RD, Zhu H
t_half (Half-life)	45 hours	Lombardo F, Berellini G, Obach RS
EoM (Fraction excreted unchanged in urine)	3.90 %	Benet LZ, Broccatelli F, Oprea TI
Vd (Volume of distribution)	1.90 L/kg	Lombardo F, Berellini G, Obach RS
BDDCS (Biopharmaceutical Drug Disposition Classification System)	1	Benet LZ, Broccatelli F, Oprea TI
CL (Clearance)	0.57 mL/min/kg	Lombardo F, Berellini G, Obach RS
fu (Fraction unbound in plasma)	0.41 %	Lombardo F, Berellini G, Obach RS
MRTD (Maximum Recommended Therapeutic Daily Dose)	0.15 µM/kg/day	Contrera JF, Matthews EJ, Kruhlak NL, Benz RD
S (Water solubility)	0.04 mg/mL	Benet LZ, Broccatelli F, Oprea TI

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Approvals:

Date	Agency	Company	Orphan
Jan. 23, 2006	PMDA	Novartis
July 25, 1997	FDA	NOVARTIS PHARMS

FDA Adverse Event Reporting System (Female)

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MedDRA adverse event term	Likelihood ratio	Likelihood ratio threshold	Patients taking drug having adverse event	Patients taking drug not having adverse event	Patients not taking drug having adverse event	Patients not taking drug not having adverse event
Neutropenia	3260.34	11.59	2653	115510	172352	63198507
Malignant neoplasm progression	3186.80	11.59	1952	116211	80169	63290690
Metastases to bone	2474.29	11.59	1058	117105	19961	63350898
Neoplasm progression	2422.91	11.59	1235	116928	35193	63335666
Metastases to liver	1663.44	11.59	833	117330	22806	63348053
White blood cell count decreased	1358.43	11.59	1476	116687	137628	63233231
Disease progression	778.14	11.59	1047	117116	121711	63249148
Hot flush	737.80	11.59	672	117491	50487	63320372
Leukopenia	732.17	11.59	808	117355	76482	63294377
Drug ineffective	718.51	11.59	542	117621	1044223	62326636

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FDA Adverse Event Reporting System (Male)

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MedDRA adverse event term	Likelihood ratio	Likelihood ratio threshold	Patients taking drug having adverse event	Patients taking drug not having adverse event	Patients not taking drug having adverse event	Patients not taking drug not having adverse event
Product use issue	113.67	29.11	52	1214	63164	34892501
Metastases to lung	66.25	29.11	21	1245	9299	34946366
Epiphysiolysis	53.09	29.11	8	1258	99	34955566
Hot flush	45.79	29.11	19	1247	18047	34937618
Metastases to bone	42.27	29.11	16	1250	11954	34943711
Hyporesponsive to stimuli	39.79	29.11	9	1257	1099	34954566
Neoplasm progression	35.00	29.11	17	1249	23283	34932382
Drug exposure before pregnancy	34.67	29.11	4	1262	3	34955662
Wrong patient received product	31.98	29.11	9	1257	2645	34953020
PIK3CA-activated mutation	31.07	29.11	5	1261	97	34955568

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FDA Adverse Event Reporting System (Geriatric)

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MedDRA adverse event term	Likelihood ratio	Likelihood ratio threshold	Patients taking drug having adverse event	Patients taking drug not having adverse event	Patients not taking drug having adverse event	Patients not taking drug not having adverse event
Neoplasm progression	2055.56	12.24	1053	89122	50629	79603584
Neutropenia	1923.74	12.24	1973	88202	285737	79368476
Metastases to bone	1786.46	12.24	759	89416	23668	79630545
White blood cell count decreased	1333.87	12.24	1334	88841	186954	79467259
Malignant neoplasm progression	1304.95	12.24	1141	89034	134849	79519364
Metastases to liver	1030.45	12.24	544	89631	27770	79626443
Fatigue	705.94	12.24	2474	87701	927253	78726960
Hot flush	667.90	12.24	529	89646	54348	79599865
Breast cancer metastatic	604.37	12.24	260	89915	8342	79645871
Alopecia	543.26	12.24	953	89222	230402	79423811

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FDA Adverse Event Reporting System (Pediatric)

None

Pharmacologic Action:

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Source	Code	Description
ATC	L02BG04	ANTINEOPLASTIC AND IMMUNOMODULATING AGENTS ENDOCRINE THERAPY HORMONE ANTAGONISTS AND RELATED AGENTS Aromatase inhibitors
CHEBI has role	CHEBI:35610	antineoplastic agents
CHEBI has role	CHEBI:50790	aromatase inhibitors
FDA EPC	N0000175563	Aromatase Inhibitor
FDA MoA	N0000175080	Aromatase Inhibitors
MeSH PA	D000970	Antineoplastic Agents
MeSH PA	D047072	Aromatase Inhibitors
MeSH PA	D004791	Enzyme Inhibitors
MeSH PA	D004965	Estrogen Antagonists
MeSH PA	D006727	Hormone Antagonists

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Drug Use | Suggest Off label Use Form| |View source of the data|

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Disease	Relation	SNOMED_ID	DOID
Induction of ovulation in polycystic ovarian syndrome	indication	237055002	DOID:11612
Induction of ovulation in unexplained infertility	indication	237145004
Hormone receptor positive malignant neoplasm of breast	indication	417181009
Controlled ovarian stimulation	indication	732970000
Early Breast Cancer Hormone Receptor Positive and Postmenopausal	indication
Malignant tumor of ovary	off-label use	363443007	DOID:2394
Hypercholesterolemia	contraindication	13644009
Hyperbilirubinemia	contraindication	14783006	DOID:2741
Cirrhosis of liver	contraindication	19943007	DOID:5082
Hepatic failure	contraindication	59927004

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🐶 Veterinary Drug Use

None

🐶 Veterinary products

None

Acid dissociation constants calculated using MoKa v3.0.0

Dissociation level	Dissociation constant	Type (acidic/basic)
pKa1	3.04	Basic

Orange Book patent data (new drug applications)

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Formulation strength	Trade name	Applicant	Application number	Approval date	Type	Dose form	Route	Patent number	Patent expiration date	Patent use
2.5MG;EQ 200MG BASE	KISQALI FEMARA CO-PACK (COPACKAGED)	NOVARTIS	N209935	May 4, 2017	RX	TABLET	ORAL	9416136	Aug. 20, 2029	AS INITIAL ENDOCRINE-BASED THERAPY FOR THE TREATMENT OF ADULT PATIENTS WITH HORMONE RECEPTOR (HR)-POSITIVE, HUMAN EPIDERMAL GROWTH FACTOR RECEPTOR 2 (HER2)-NEGATIVE ADVANCED OR METASTATIC BREAST CANCER
2.5MG;EQ 200MG BASE	KISQALI FEMARA CO-PACK (COPACKAGED)	NOVARTIS	N209935	May 4, 2017	RX	TABLET	ORAL	9416136	Aug. 20, 2029	TREATMENT OF PRE/PERIMENOPAUSAL WOMEN WITH HORMONE RECEPTOR (HR)-POSITIVE, HUMAN EPIDERMAL GROWTH FACTOR RECEPTOR 2 (HER2)-NEGATIVE ADVANCED OR METASTATIC BREAST CANCER
2.5MG;EQ 200MG BASE	KISQALI FEMARA CO-PACK (COPACKAGED)	NOVARTIS	N209935	May 4, 2017	RX	TABLET	ORAL	8962630	Dec. 9, 2029	AS INITIAL ENDOCRINE-BASED THERAPY FOR THE TREATMENT OF ADULT PATIENTS WITH HORMONE RECEPTOR (HR)-POSITIVE, HUMAN EPIDERMAL GROWTH FACTOR RECEPTOR 2 (HER2)-NEGATIVE ADVANCED OR METASTATIC BREAST CANCER
2.5MG;EQ 200MG BASE	KISQALI FEMARA CO-PACK (COPACKAGED)	NOVARTIS	N209935	May 4, 2017	RX	TABLET	ORAL	8962630	Dec. 9, 2029	TREATMENT OF PRE/PERIMENOPAUSAL WOMEN WITH HORMONE RECEPTOR (HR)-POSITIVE, HUMAN EPIDERMAL GROWTH FACTOR RECEPTOR 2 (HER2)-NEGATIVE ADVANCED OR METASTATIC BREAST CANCER
2.5MG;EQ 200MG BASE	KISQALI FEMARA CO-PACK (COPACKAGED)	NOVARTIS	N209935	May 4, 2017	RX	TABLET	ORAL	9868739	Nov. 9, 2031	AS INITIAL ENDOCRINE-BASED THERAPY FOR THE TREATMENT OF ADULT PATIENTS WITH HORMONE RECEPTOR (HR)-POSITIVE, HUMAN EPIDERMAL GROWTH FACTOR RECEPTOR 2 (HER2)-NEGATIVE ADVANCED OR METASTATIC BREAST CANCER
2.5MG;EQ 200MG BASE	KISQALI FEMARA CO-PACK (COPACKAGED)	NOVARTIS	N209935	May 4, 2017	RX	TABLET	ORAL	9868739	Nov. 9, 2031	TREATMENT OF PRE/PERIMENOPAUSAL WOMEN WITH HORMONE RECEPTOR (HR)-POSITIVE, HUMAN EPIDERMAL GROWTH FACTOR RECEPTOR 2 (HER2)-NEGATIVE ADVANCED OR METASTATIC BREAST CANCER

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Orange Book exclusivity data (new drug applications)

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Formulation strength	Trade name	Applicant	Application number	Approval date	Type	Dose form	Route	Exclusivity date	Description
2.5MG;EQ 200MG BASE	KISQALI FEMARA CO-PACK (COPACKAGED)	NOVARTIS	N209935	May 4, 2017	RX	TABLET	ORAL	Dec. 10, 2024	NEW PATIENT POPULATION

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Bioactivity Summary:

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Target	Class	Pharos	UniProt	Action	Type	Activity value (-log[M])	Bioact source	MoA source
Aromatase	Enzyme	P11511	CP19A_HUMAN	INHIBITOR	IC50	8.22	WOMBAT-PK	CHEMBL
Cytochrome P450 11B1, mitochondrial	Enzyme	P15538	C11B1_HUMAN		IC50	5.58	CHEMBL
Cytochrome P450 11B2, mitochondrial	Enzyme	P19099	C11B2_HUMAN		IC50	5.85	CHEMBL

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External reference:

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ID	Source
006298	NDDF
108777007	SNOMEDCT_US
11317	MMSL
173561	MMSL
203769	RXNORM
386911004	SNOMEDCT_US
3902	PUBCHEM_CID
4021049	VUID
4021049	VANDF
4963	MMSL

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Pharmaceutical products:

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Product	Category	Ingredients	NDC	Form	Quantity	Route	Marketing	Label
Femara	HUMAN PRESCRIPTION DRUG LABEL	1	0078-0249	TABLET, FILM COATED	2.50 mg	ORAL	NDA	27 sections
Femara	HUMAN PRESCRIPTION DRUG LABEL	1	0078-0249	TABLET, FILM COATED	2.50 mg	ORAL	NDA	27 sections
Femara	HUMAN PRESCRIPTION DRUG LABEL	1	0078-0249	TABLET, FILM COATED	2.50 mg	ORAL	NDA	27 sections
Femara	HUMAN PRESCRIPTION DRUG LABEL	1	54868-4151	TABLET, FILM COATED	2.50 mg	ORAL	NDA	26 sections
Letrozole	HUMAN PRESCRIPTION DRUG LABEL	1	0093-7620	TABLET, FILM COATED	2.50 mg	ORAL	ANDA	26 sections
Letrozole	HUMAN PRESCRIPTION DRUG LABEL	1	0093-7620	TABLET, FILM COATED	2.50 mg	ORAL	ANDA	26 sections
Letrozole	HUMAN PRESCRIPTION DRUG LABEL	1	16729-034	TABLET, FILM COATED	2.50 mg	ORAL	ANDA	25 sections
Letrozole	HUMAN PRESCRIPTION DRUG LABEL	1	16729-034	TABLET, FILM COATED	2.50 mg	ORAL	ANDA	25 sections
Letrozole	HUMAN PRESCRIPTION DRUG LABEL	1	17856-0032	TABLET, FILM COATED	2.50 mg	ORAL	ANDA	25 sections
Letrozole	HUMAN PRESCRIPTION DRUG LABEL	1	23155-875	TABLET, FILM COATED	2.50 mg	ORAL	ANDA	26 sections

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