Formestane

Identification

Name

Formestane

Accession Number

DB08905

Type

Small Molecule

Groups

Approved, Investigational, Withdrawn

Description

Formestane was the first selective, type I, steroidal aromatase inhibitor used in the treatment of estrogen-receptor positive breast cancer in post-menopausal women. Formestane suppresses estrogen production from anabolic steroids or prohormones. It also acts as a prohormone to 4-hydroxytestosterone, an active steroid which displays weak androgenic activity in addition to acting as a mild aromatase inhibitor. It is listed as a prohibited substance by the World Anti-Doping Agency for use in athletes.

Formestane has poor oral bioavailability, and thus must be administered forthnightly (bi-weekly) by intramuscular injection. Some clinical data has suggested that the clinically recommended dose of 250mg was too low. With the discovery of newer, non-steroidal and steroidal, aromatase inhibitors which were orally active and less expensive than formestane, formestane lost popularity.

Currently, formestane (categorized as an anti-estrogenic agent) is prohibited from use in sports in accordance to the regulations of the World Anti-Doping Agency. It is not US FDA approved, and the intramuscular injection form of formestane (Lentaron) which was approved in Europe has been withdrawn.

Structure

3D

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MOLSDF3D-SDFPDBSMILESInChI

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Structure for DB08905 (Formestane)

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Synonyms

• 4-hydroxy-4-androstene-3,17-dione
• 4-Hydroxy-delta(4)-androstenedione
• 4-hydroxy-Δ4-androstenedione
• 4-hydroxyandrostenedione
• 4-OH-A
• 4-OHAD
• Formestano
• Formestanum

External IDs

CGP 32349 / CGP-32349

Product Ingredients

Not Available

Approved Prescription Products

Not Available

Approved Generic Prescription Products

Not Available

Approved Over the Counter Products

Not Available

Unapproved/Other Products

Not Available

International/Other Brands

Lentaron

Brand mixtures

Name	Ingredients	Dosage	Route	Labeller	Marketing Start	Marketing End
Lentaron	Formestane Sodium Chloride	Liquid; Powder, for solution	Intramuscular	Novartis	1994-12-31	1999-08-04

Categories

• 17-Ketosteroids
• Adrenal Cortex Hormones
• Androstanes
• Androstenes
• Antineoplastic Agents
• Antineoplastic and Immunomodulating Agents
• Aromatase Inhibitors
• Endocrine Therapy
• Enzyme Inhibitors
• Estrogen Antagonists
• Gonadal Hormones
• Gonadal Steroid Hormones
• Hormone Antagonists
• Hormone Antagonists and Related Agents
• Hormones
• Hormones, Hormone Substitutes, and Hormone Antagonists
• Ketosteroids
• Steroid Synthesis Inhibitors
• Steroids
• Testosterone Congeners

UNII

PUB9T8T355

CAS number

566-48-3

Weight

Average: 302.4079
Monoisotopic: 302.188194698

Chemical Formula

C₁₉H₂₆O₃

InChI Key

OSVMTWJCGUFAOD-KZQROQTASA-N

InChI

InChI=1S/C19H26O3/c1-18-10-8-15(20)17(22)14(18)4-3-11-12-5-6-16(21)19(12,2)9-7-13(11)18/h11-13,22H,3-10H2,1-2H3/t11-,12-,13-,18+,19-/m0/s1

IUPAC Name

(1S,2R,10R,11S,15S)-6-hydroxy-2,15-dimethyltetracyclo[8.7.0.0²,⁷.0¹¹,¹⁵]heptadec-6-ene-5,14-dione

SMILES

[H][[email protected]@]12CCC(=O)[[email protected]@]1(C)CC[[email protected]@]1([H])[[email protected]@]2([H])CCC2=C(O)C(=O)CC[[email protected]]12C

Pharmacology

Indication

For the treatment of estrogen-receptor positive breast cancer in post-menopausal women.

Structured Indications

Not Available

Pharmacodynamics

By significantly reducing estrogen levels in the bloodstream, formestane may exhibit antitumor activity.

In one trial involving 147 postmenopausal females with advanced breast cancers resistant to standard therapies, 22% of patients achieved a partial response, while another 20% achieved disease stabilization. [3]

In comparative trials comparing a non-steroidal aromatase inhibitor, anastrozole, with formestane, it was found that anastrozole was more effective and consistent at suppressing estrogen levels in the body. However, these results were of unverified clinical significance. [5]

Mechanism of action

Formestane is a second generation, irreversible, steroidal aromatase inhibitor. It inhibits the aromatase enzyme responsible for converting androgens to estrogens, thereby preventing estrogen production.

Breast cancer may be estrogen sensitive or insensitive. A majority of breast cancers are estrogen sensitive. Estrogen sensitive breast cancer cells depend on estrogen for viability. Thus removal of estrogen from the body can be an effective treatment for hormone sensitive breast cancers.

Formestane has been targeted specifically for the treatment of postmenopausal women. Unlike premenopausal women who produce most estrogen in the ovaries, postmenopausal women produce most estrogen in peripheral tissues with the help of the aromatase enzyme. Formestane, an aromatase inhibitor, can thus help to decrease the local production of estrogen by blocking the aromatase enzyme in peripheral tissues (ie. adispose tissue of the breast) to treat hormone sensitive breast cancer.

Absorption

Formestane has poor oral bioavailability, but is fully bioavailable when administered via the established intramuscular route. The AUC after an intravenous pulse dose does not vary considerably from that of an intramuscular dose.

Within 24-48 h of the first dose of intramuscular formestane, a C(max) of 48.0 +/- 20.9 nmol/l was achieved in one study. [2]

Volume of distribution

Vd = 1.8 L/kg; widely distributed to organs and tissues when delivered intravenously. [2]

Protein binding

Not Available

Metabolism

Hepatic metabolism. Phase I of metabolism is mainly reductive in nature. The reduction products 3 beta-hydroxy-5alpha-androstane-4,17-dione and 3alpha-hydroxy-5beta-androstane-4,17-dione are produced, and further reduced. A notable step in the process of metabolism is a keto reduction on carbon number three of the molecule. The main metabolite which is produced from formestane is 4-hydroyxyandrost-4-ene-3,17-dione-4-glucuronide.

The oxidation products identified were 4-hydroxyandrosta-4,6-diene-3,17-dione and 4-hydroxyandrosta-1,4-diene-3,17-dione.

In phase II, conjugation was diverse and included sulfatation and glucuronidation. 4-hydroxytestosterone, the 17-hydroxylated analog to formestane, was identified as one particular metabolite found in women's urine. This finding was the result of an oral administration of 500mg of formestane in women.

Reactions:

• Formestane
  4-Hydroxyandrostenedione glucuronide

Route of elimination

Renal elimination. >95% in urine, <5% in feces.

Half life

Terminal plasma elimination half life of 18 minutes, when delivered intravenously. [2]

Clearance

Plasma clearance is approximately 4.2 L/(h kg), when delivered intravenously.

In women, following a 500mg dose of formestane, 20% was excreted as glucuronide within the first 24 hours. [1]

One long term metabolite (3beta,4alpha-dihydroxy-5alpha-androstan-17-one) can be detected for 90 hours. A longer detection time is possible with more sensitive technology, which may be of utility in sports drug testing. [1]

Toxicity

Not Available

Affected organisms

Not Available

Pathways

Not Available

Pharmacogenomic Effects/ADRs

Not Available

Interactions

Drug Interactions

Drug	Interaction	Drug group
1,10-Phenanthroline	The risk or severity of adverse effects can be increased when Formestane is combined with 1,10-Phenanthroline.	Experimental
Aceclofenac	The risk or severity of adverse effects can be increased when Aceclofenac is combined with Formestane.	Approved
Acetyldigitoxin	Acetyldigitoxin may decrease the cardiotoxic activities of Formestane.	Approved
Acetylsalicylic acid	The risk or severity of adverse effects can be increased when Acetylsalicylic acid is combined with Formestane.	Approved, Vet Approved
Adapalene	The risk or severity of adverse effects can be increased when Adapalene is combined with Formestane.	Approved
Aldesleukin	Formestane may decrease the antineoplastic activities of Aldesleukin.	Approved
Aluminum hydroxide	The bioavailability of Formestane can be decreased when combined with Aluminum hydroxide.	Approved
Ambenonium	The risk or severity of adverse effects can be increased when Formestane is combined with Ambenonium.	Approved
Aminosalicylic Acid	The risk or severity of adverse effects can be increased when Aminosalicylic Acid is combined with Formestane.	Approved
Amiodarone	The serum concentration of Formestane can be increased when it is combined with Amiodarone.	Approved, Investigational
Amphotericin B	Formestane may increase the hypokalemic activities of Amphotericin B.	Approved, Investigational
Andrographolide	The risk or severity of adverse effects can be increased when HMPL-004 is combined with Formestane.	Investigational
Anisodamine	The risk or severity of adverse effects can be increased when Anisodamine is combined with Formestane.	Investigational
Antipyrine	The risk or severity of adverse effects can be increased when Antipyrine is combined with Formestane.	Approved
Apocynin	The risk or severity of adverse effects can be increased when Acetovanillone is combined with Formestane.	Investigational
Apremilast	The risk or severity of adverse effects can be increased when Apremilast is combined with Formestane.	Approved, Investigational
Aprepitant	The serum concentration of Formestane can be increased when it is combined with Aprepitant.	Approved, Investigational
Atazanavir	The serum concentration of Formestane can be increased when it is combined with Atazanavir.	Approved, Investigational
Atracurium besylate	Atracurium besylate may increase the adverse neuromuscular activities of Formestane.	Approved
Azapropazone	The risk or severity of adverse effects can be increased when Azapropazone is combined with Formestane.	Withdrawn
Azelastine	The risk or severity of adverse effects can be increased when Azelastine is combined with Formestane.	Approved
Balsalazide	The risk or severity of adverse effects can be increased when Balsalazide is combined with Formestane.	Approved, Investigational
Bazedoxifene	The serum concentration of Formestane can be increased when it is combined with Bazedoxifene.	Approved, Investigational
Bendroflumethiazide	Formestane may increase the hypokalemic activities of Bendroflumethiazide.	Approved
Benoxaprofen	The risk or severity of adverse effects can be increased when Benoxaprofen is combined with Formestane.	Withdrawn
Benzoic Acid	The therapeutic efficacy of Benzoic Acid can be decreased when used in combination with Formestane.	Approved
Betulinic Acid	The risk or severity of adverse effects can be increased when Betulinic Acid is combined with Formestane.	Investigational
Bevacizumab	Bevacizumab may increase the cardiotoxic activities of Formestane.	Approved, Investigational
Bismuth Subcitrate	The bioavailability of Formestane can be decreased when combined with Bismuth Subcitrate.	Approved
Boceprevir	The serum concentration of Formestane can be increased when it is combined with Boceprevir.	Withdrawn
Bromfenac	The risk or severity of adverse effects can be increased when Bromfenac is combined with Formestane.	Approved
Bucillamine	The risk or severity of adverse effects can be increased when Bucillamine is combined with Formestane.	Investigational
Bumetanide	Formestane may increase the hypokalemic activities of Bumetanide.	Approved
Cabazitaxel	The risk or severity of adverse effects can be increased when Cabazitaxel is combined with Formestane.	Approved
Calcitriol	The therapeutic efficacy of Calcitriol can be decreased when used in combination with Formestane.	Approved, Nutraceutical
Calcium Carbonate	The bioavailability of Formestane can be decreased when combined with Calcium carbonate.	Approved
Carbamazepine	The serum concentration of Formestane can be decreased when it is combined with Carbamazepine.	Approved, Investigational
Carprofen	The risk or severity of adverse effects can be increased when Carprofen is combined with Formestane.	Approved, Vet Approved, Withdrawn
Castanospermine	The risk or severity of adverse effects can be increased when Castanospermine is combined with Formestane.	Experimental
Celecoxib	The risk or severity of adverse effects can be increased when Celecoxib is combined with Formestane.	Approved, Investigational
Ceritinib	Formestane may increase the hyperglycemic activities of Ceritinib.	Approved
Chloroquine	The risk or severity of adverse effects can be increased when Chloroquine is combined with Formestane.	Approved, Vet Approved
Chlorothiazide	Formestane may increase the hypokalemic activities of Chlorothiazide.	Approved, Vet Approved
Chlorotrianisene	The serum concentration of Formestane can be increased when it is combined with Chlorotrianisene.	Withdrawn
Chlorthalidone	Formestane may increase the hypokalemic activities of Chlorthalidone.	Approved
Cholestyramine	Cholestyramine can cause a decrease in the absorption of Formestane resulting in a reduced serum concentration and potentially a decrease in efficacy.	Approved
Choline magnesium trisalicylate	The risk or severity of adverse effects can be increased when Trisalicylate-choline is combined with Formestane.	Approved
Cinoxacin	The risk or severity of adverse effects can be increased when Formestane is combined with Cinoxacin.	Approved, Withdrawn
Ciprofloxacin	The risk or severity of adverse effects can be increased when Formestane is combined with Ciprofloxacin.	Approved, Investigational
Clarithromycin	The serum concentration of Formestane can be increased when it is combined with Clarithromycin.	Approved
Clonixin	The risk or severity of adverse effects can be increased when Clonixin is combined with Formestane.	Approved
Cobicistat	The serum concentration of Formestane can be increased when it is combined with Cobicistat.	Approved
Colesevelam	Colesevelam can cause a decrease in the absorption of Formestane resulting in a reduced serum concentration and potentially a decrease in efficacy.	Approved
Colestipol	Colestipol can cause a decrease in the absorption of Formestane resulting in a reduced serum concentration and potentially a decrease in efficacy.	Approved
Conjugated estrogens	The serum concentration of Formestane can be increased when it is combined with Conjugated Equine Estrogens.	Approved
Corticorelin ovine triflutate	The therapeutic efficacy of Corticorelin ovine triflutate can be decreased when used in combination with Formestane.	Approved
Coumaphos	The risk or severity of adverse effects can be increased when Formestane is combined with Coumaphos.	Vet Approved
Curcumin	The risk or severity of adverse effects can be increased when Curcumin is combined with Formestane.	Investigational
Cyclophosphamide	Cyclophosphamide may increase the cardiotoxic activities of Formestane.	Approved, Investigational
D-Limonene	The risk or severity of adverse effects can be increased when D-Limonene is combined with Formestane.	Investigational
Darunavir	The serum concentration of Formestane can be increased when it is combined with Darunavir.	Approved
Decamethonium	The risk or severity of adverse effects can be increased when Formestane is combined with Decamethonium.	Approved
Deferasirox	The risk or severity of adverse effects can be increased when Formestane is combined with Deferasirox.	Approved, Investigational
Demecarium	The risk or severity of adverse effects can be increased when Formestane is combined with Demecarium.	Approved
dersalazine	The risk or severity of adverse effects can be increased when dersalazine is combined with Formestane.	Investigational
Deslanoside	Deslanoside may decrease the cardiotoxic activities of Formestane.	Approved
Dichlorvos	The risk or severity of adverse effects can be increased when Formestane is combined with Dichlorvos.	Vet Approved
Diclofenac	The risk or severity of adverse effects can be increased when Diclofenac is combined with Formestane.	Approved, Vet Approved
Dienestrol	The serum concentration of Formestane can be increased when it is combined with Dienestrol.	Approved
Diethylstilbestrol	The serum concentration of Formestane can be increased when it is combined with Diethylstilbestrol.	Approved
Diflunisal	The risk or severity of adverse effects can be increased when Diflunisal is combined with Formestane.	Approved
Digitoxin	Digitoxin may decrease the cardiotoxic activities of Formestane.	Approved
Digoxin	Digoxin may decrease the cardiotoxic activities of Formestane.	Approved
Dihydrotestosterone	Formestane may increase the fluid retaining activities of Dihydrotestosterone.	Illicit
Docetaxel	The risk or severity of adverse effects can be increased when Docetaxel is combined with Formestane.	Approved, Investigational
Donepezil	The risk or severity of adverse effects can be increased when Formestane is combined with Donepezil.	Approved
Droxicam	The risk or severity of adverse effects can be increased when Droxicam is combined with Formestane.	Approved
Duvelisib	The risk or severity of adverse effects can be increased when Duvelisib is combined with Formestane.	Investigational
E-6201	The risk or severity of adverse effects can be increased when E6201 is combined with Formestane.	Investigational
Ebselen	The risk or severity of adverse effects can be increased when Ebselen is combined with Formestane.	Investigational
Echothiophate	The risk or severity of adverse effects can be increased when Formestane is combined with Echothiophate.	Approved
Edrophonium	The risk or severity of adverse effects can be increased when Formestane is combined with Edrophonium.	Approved
Enoxacin	The risk or severity of adverse effects can be increased when Formestane is combined with Enoxacin.	Approved
Enzalutamide	The serum concentration of Formestane can be decreased when it is combined with Enzalutamide.	Approved
Epirizole	The risk or severity of adverse effects can be increased when Epirizole is combined with Formestane.	Approved
Equol	The serum concentration of Formestane can be increased when it is combined with S Equol.	Investigational
Estradiol	The serum concentration of Formestane can be increased when it is combined with Estradiol.	Approved, Investigational, Vet Approved
Estriol	The serum concentration of Formestane can be increased when it is combined with Estriol.	Approved, Vet Approved
Estrone	The serum concentration of Formestane can be increased when it is combined with Estrone.	Approved
Etacrynic acid	Formestane may increase the hypokalemic activities of Etacrynic acid.	Approved
Etanercept	The risk or severity of adverse effects can be increased when Etanercept is combined with Formestane.	Approved, Investigational
Ethinyl Estradiol	The serum concentration of Formestane can be increased when it is combined with Ethinyl Estradiol.	Approved
Etodolac	The risk or severity of adverse effects can be increased when Etodolac is combined with Formestane.	Approved, Investigational, Vet Approved
Etofenamate	The risk or severity of adverse effects can be increased when Etofenamate is combined with Formestane.	Approved
Etoricoxib	The risk or severity of adverse effects can be increased when Etoricoxib is combined with Formestane.	Approved, Investigational
Evening primrose oil	The risk or severity of adverse effects can be increased when Evening primrose oil is combined with Formestane.	Approved
exisulind	The risk or severity of adverse effects can be increased when exisulind is combined with Formestane.	Investigational
Fenbufen	The risk or severity of adverse effects can be increased when Fenbufen is combined with Formestane.	Approved
Fenoprofen	The risk or severity of adverse effects can be increased when Fenoprofen is combined with Formestane.	Approved
Fenthion	The risk or severity of adverse effects can be increased when Formestane is combined with Fenthion.	Vet Approved
Fleroxacin	The risk or severity of adverse effects can be increased when Formestane is combined with Fleroxacin.	Approved
Floctafenine	The risk or severity of adverse effects can be increased when Floctafenine is combined with Formestane.	Approved, Withdrawn
Flumequine	The risk or severity of adverse effects can be increased when Formestane is combined with Flumequine.	Withdrawn
Flunixin	The risk or severity of adverse effects can be increased when Flunixin is combined with Formestane.	Vet Approved
Fluoxymesterone	Formestane may increase the fluid retaining activities of Fluoxymesterone.	Approved, Illicit
Flurbiprofen	The risk or severity of adverse effects can be increased when Flurbiprofen is combined with Formestane.	Approved, Investigational
Fosaprepitant	The serum concentration of Formestane can be increased when it is combined with Fosaprepitant.	Approved
Fosphenytoin	The serum concentration of Formestane can be decreased when it is combined with Fosphenytoin.	Approved
Furosemide	Formestane may increase the hypokalemic activities of Furosemide.	Approved, Vet Approved
G17DT	The risk or severity of adverse effects can be increased when Formestane is combined with G17DT.	Investigational
Galantamine	The risk or severity of adverse effects can be increased when Formestane is combined with Galantamine.	Approved
Gallamine Triethiodide	The risk or severity of adverse effects can be increased when Formestane is combined with Gallamine Triethiodide.	Approved
Garenoxacin	The risk or severity of adverse effects can be increased when Formestane is combined with Garenoxacin.	Investigational
Gatifloxacin	The risk or severity of adverse effects can be increased when Formestane is combined with Gatifloxacin.	Approved, Investigational
Gemifloxacin	The risk or severity of adverse effects can be increased when Formestane is combined with Gemifloxacin.	Approved, Investigational
Genistein	The serum concentration of Formestane can be increased when it is combined with Genistein.	Investigational
GI-5005	The risk or severity of adverse effects can be increased when Formestane is combined with GI-5005.	Investigational
Ginkgo biloba	The risk or severity of adverse effects can be increased when Formestane is combined with Ginkgo biloba.	Approved, Nutraceutical
Glycerol Phenylbutyrate	The therapeutic efficacy of Glycerol Phenylbutyrate can be decreased when used in combination with Formestane.	Approved
Grepafloxacin	The risk or severity of adverse effects can be increased when Formestane is combined with Grepafloxacin.	Withdrawn
Hexestrol	The serum concentration of Formestane can be increased when it is combined with Hexestrol.	Withdrawn
Higenamine	The risk or severity of adverse effects can be increased when Higenamine is combined with Formestane.	Investigational
Huperzine A	The risk or severity of adverse effects can be increased when Formestane is combined with Huperzine A.	Investigational
Hyaluronidase	The therapeutic efficacy of Hyaluronidase can be decreased when used in combination with Formestane.	Approved, Investigational
Hydrochlorothiazide	Formestane may increase the hypokalemic activities of Hydrochlorothiazide.	Approved, Vet Approved
Hydroflumethiazide	Formestane may increase the hypokalemic activities of Hydroflumethiazide.	Approved
Ibuprofen	The risk or severity of adverse effects can be increased when Ibuprofen is combined with Formestane.	Approved
Ibuproxam	The risk or severity of adverse effects can be increased when Ibuproxam is combined with Formestane.	Withdrawn
Icatibant	The risk or severity of adverse effects can be increased when Icatibant is combined with Formestane.	Approved
Idelalisib	The serum concentration of Formestane can be increased when it is combined with Idelalisib.	Approved
Indacaterol	Indacaterol may increase the hypokalemic activities of Formestane.	Approved
Indapamide	Formestane may increase the hypokalemic activities of Indapamide.	Approved
Indinavir	The serum concentration of Formestane can be increased when it is combined with Indinavir.	Approved
Indomethacin	The risk or severity of adverse effects can be increased when Indomethacin is combined with Formestane.	Approved, Investigational
Indoprofen	The risk or severity of adverse effects can be increased when Indoprofen is combined with Formestane.	Withdrawn
INGN 201	The risk or severity of adverse effects can be increased when Formestane is combined with INGN 201.	Investigational
INGN 225	The risk or severity of adverse effects can be increased when Formestane is combined with INGN 225.	Investigational
Isoflurophate	The risk or severity of adverse effects can be increased when Formestane is combined with Isoflurophate.	Approved, Withdrawn
Isoniazid	The serum concentration of Isoniazid can be decreased when it is combined with Formestane.	Approved
Isoxicam	The risk or severity of adverse effects can be increased when Isoxicam is combined with Formestane.	Withdrawn
Itraconazole	The serum concentration of Formestane can be increased when it is combined with Itraconazole.	Approved, Investigational
Kebuzone	The risk or severity of adverse effects can be increased when Kebuzone is combined with Formestane.	Experimental
Ketoconazole	The serum concentration of Formestane can be increased when it is combined with Ketoconazole.	Approved, Investigational
Ketoprofen	The risk or severity of adverse effects can be increased when Ketoprofen is combined with Formestane.	Approved, Vet Approved
Ketorolac	The risk or severity of adverse effects can be increased when Ketorolac is combined with Formestane.	Approved
Leflunomide	The risk or severity of adverse effects can be increased when Leflunomide is combined with Formestane.	Approved, Investigational
Levofloxacin	The risk or severity of adverse effects can be increased when Formestane is combined with Levofloxacin.	Approved, Investigational
Lisofylline	The risk or severity of adverse effects can be increased when Lisofylline is combined with Formestane.	Investigational
Lomefloxacin	The risk or severity of adverse effects can be increased when Formestane is combined with Lomefloxacin.	Approved
Lopinavir	The serum concentration of Formestane can be increased when it is combined with Lopinavir.	Approved
Lornoxicam	The risk or severity of adverse effects can be increased when Lornoxicam is combined with Formestane.	Approved
Loxoprofen	The risk or severity of adverse effects can be increased when Loxoprofen is combined with Formestane.	Approved
Lumacaftor	The serum concentration of Formestane can be decreased when it is combined with Lumacaftor.	Approved
Lumiracoxib	The risk or severity of adverse effects can be increased when Lumiracoxib is combined with Formestane.	Approved, Investigational
Magaldrate	The bioavailability of Formestane can be decreased when combined with Magaldrate.	Withdrawn
Magnesium carbonate	The bioavailability of Formestane can be decreased when combined with Magnesium carbonate.	Approved
Magnesium Hydroxide	The bioavailability of Formestane can be decreased when combined with Magnesium hydroxide.	Approved
Magnesium oxide	The bioavailability of Formestane can be decreased when combined with Magnesium oxide.	Approved
Magnesium salicylate	The risk or severity of adverse effects can be increased when Magnesium salicylate is combined with Formestane.	Approved
Magnesium Trisilicate	The bioavailability of Formestane can be decreased when combined with Magnesium Trisilicate.	Approved
Malathion	The risk or severity of adverse effects can be increased when Formestane is combined with Malathion.	Approved, Investigational
Masoprocol	The risk or severity of adverse effects can be increased when Masoprocol is combined with Formestane.	Approved
Meclofenamic acid	The risk or severity of adverse effects can be increased when Meclofenamic acid is combined with Formestane.	Approved, Vet Approved
Mefenamic acid	The risk or severity of adverse effects can be increased when Mefenamic acid is combined with Formestane.	Approved
Mefloquine	The risk or severity of adverse effects can be increased when Formestane is combined with Mefloquine.	Approved
Meloxicam	The risk or severity of adverse effects can be increased when Meloxicam is combined with Formestane.	Approved, Vet Approved
Memantine	The risk or severity of adverse effects can be increased when Formestane is combined with Memantine.	Approved, Investigational
Mesalazine	The risk or severity of adverse effects can be increased when Mesalazine is combined with Formestane.	Approved
Mestranol	The serum concentration of Formestane can be increased when it is combined with Mestranol.	Approved
Metamizole	The risk or severity of adverse effects can be increased when Metamizole is combined with Formestane.	Withdrawn
Methadone	The serum concentration of Methadone can be increased when it is combined with Formestane.	Approved
Methallenestril	The serum concentration of Formestane can be increased when it is combined with Methallenestril.	Experimental
Methanesulfonyl Fluoride	The risk or severity of adverse effects can be increased when Formestane is combined with Methanesulfonyl Fluoride.	Investigational
Methyclothiazide	Formestane may increase the hypokalemic activities of Methyclothiazide.	Approved
Methyltestosterone	Formestane may increase the fluid retaining activities of Methyltestosterone.	Approved
Metolazone	Formestane may increase the hypokalemic activities of Metolazone.	Approved
Mifepristone	The therapeutic efficacy of Formestane can be decreased when used in combination with Mifepristone.	Approved, Investigational
Minaprine	The risk or severity of adverse effects can be increased when Formestane is combined with Minaprine.	Approved
Mitotane	The serum concentration of Formestane can be decreased when it is combined with Mitotane.	Approved
Mivacurium	Mivacurium may increase the adverse neuromuscular activities of Formestane.	Approved
Mizoribine	The risk or severity of adverse effects can be increased when Mizoribine is combined with Formestane.	Investigational
Moxifloxacin	The risk or severity of adverse effects can be increased when Formestane is combined with Moxifloxacin.	Approved, Investigational
Mycophenolate mofetil	The risk or severity of adverse effects can be increased when Mycophenolate mofetil is combined with Formestane.	Approved, Investigational
Mycophenolic acid	The risk or severity of adverse effects can be increased when Mycophenolic acid is combined with Formestane.	Approved
Nabumetone	The risk or severity of adverse effects can be increased when Nabumetone is combined with Formestane.	Approved
Nafamostat	The risk or severity of adverse effects can be increased when Nafamostat is combined with Formestane.	Approved, Investigational
Naftifine	The risk or severity of adverse effects can be increased when Naftifine is combined with Formestane.	Approved
Nalidixic Acid	The risk or severity of adverse effects can be increased when Formestane is combined with Nalidixic Acid.	Approved
Naproxen	The risk or severity of adverse effects can be increased when Naproxen is combined with Formestane.	Approved, Vet Approved
Nefazodone	The serum concentration of Formestane can be increased when it is combined with Nefazodone.	Approved, Withdrawn
Nelfinavir	The serum concentration of Formestane can be increased when it is combined with Nelfinavir.	Approved
Nemonoxacin	The risk or severity of adverse effects can be increased when Formestane is combined with Nemonoxacin.	Investigational
Neostigmine	The risk or severity of adverse effects can be increased when Formestane is combined with Neostigmine.	Approved, Vet Approved
Nepafenac	The risk or severity of adverse effects can be increased when Nepafenac is combined with Formestane.	Approved
Nevirapine	The serum concentration of Formestane can be decreased when it is combined with Nevirapine.	Approved
Nicorandil	The risk or severity of adverse effects can be increased when Formestane is combined with Nicorandil.	Approved
Niflumic Acid	The risk or severity of adverse effects can be increased when Niflumic Acid is combined with Formestane.	Approved
Nimesulide	The risk or severity of adverse effects can be increased when Nimesulide is combined with Formestane.	Approved, Withdrawn
Nitroaspirin	The risk or severity of adverse effects can be increased when Nitroaspirin is combined with Formestane.	Investigational
Norfloxacin	The risk or severity of adverse effects can be increased when Formestane is combined with Norfloxacin.	Approved
Ofloxacin	The risk or severity of adverse effects can be increased when Formestane is combined with Ofloxacin.	Approved
Oleandrin	Anvirzel may decrease the cardiotoxic activities of Formestane.	Experimental
Olopatadine	The risk or severity of adverse effects can be increased when Olopatadine is combined with Formestane.	Approved
Olsalazine	The risk or severity of adverse effects can be increased when Olsalazine is combined with Formestane.	Approved
Orgotein	The risk or severity of adverse effects can be increased when Orgotein is combined with Formestane.	Vet Approved
Ouabain	Ouabain may decrease the cardiotoxic activities of Formestane.	Approved
Oxandrolone	Formestane may increase the fluid retaining activities of Oxandrolone.	Approved, Investigational
Oxaprozin	The risk or severity of adverse effects can be increased when Oxaprozin is combined with Formestane.	Approved
Oxymetholone	Formestane may increase the fluid retaining activities of Oxymetholone.	Approved, Illicit
Oxyphenbutazone	The risk or severity of adverse effects can be increased when Oxyphenbutazone is combined with Formestane.	Withdrawn
Paclitaxel	The risk or severity of adverse effects can be increased when Paclitaxel is combined with Formestane.	Approved, Vet Approved
Parecoxib	The risk or severity of adverse effects can be increased when Parecoxib is combined with Formestane.	Approved
Pazufloxacin	The risk or severity of adverse effects can be increased when Formestane is combined with Pazufloxacin.	Investigational
Pefloxacin	The risk or severity of adverse effects can be increased when Formestane is combined with Pefloxacin.	Approved
Pentobarbital	The serum concentration of Formestane can be decreased when it is combined with Pentobarbital.	Approved, Vet Approved
Phenobarbital	The serum concentration of Formestane can be decreased when it is combined with Phenobarbital.	Approved
Phenylacetic acid	The therapeutic efficacy of Phenylacetic acid can be decreased when used in combination with Formestane.	Approved
Phenylbutazone	The risk or severity of adverse effects can be increased when Phenylbutazone is combined with Formestane.	Approved, Vet Approved
Phenylbutyric acid	The therapeutic efficacy of Sodium phenylbutyrate can be decreased when used in combination with Formestane.	Approved, Investigational
Phenytoin	The serum concentration of Formestane can be decreased when it is combined with Phenytoin.	Approved, Vet Approved
Physostigmine	The risk or severity of adverse effects can be increased when Formestane is combined with Physostigmine.	Approved
Pimecrolimus	The risk or severity of adverse effects can be increased when Pimecrolimus is combined with Formestane.	Approved, Investigational
Piretanide	Formestane may increase the hypokalemic activities of Piretanide.	Experimental
Pirfenidone	The risk or severity of adverse effects can be increased when Pirfenidone is combined with Formestane.	Investigational
Piroxicam	The risk or severity of adverse effects can be increased when Piroxicam is combined with Formestane.	Approved, Investigational
Polyestradiol phosphate	The serum concentration of Formestane can be increased when it is combined with Polyestradiol phosphate.	Approved
Polythiazide	Formestane may increase the hypokalemic activities of Polythiazide.	Approved
Posaconazole	The serum concentration of Formestane can be increased when it is combined with Posaconazole.	Approved, Investigational, Vet Approved
Primidone	The serum concentration of Formestane can be decreased when it is combined with Primidone.	Approved, Vet Approved
Promestriene	The serum concentration of Formestane can be increased when it is combined with Promestriene.	Investigational
Propacetamol	The risk or severity of adverse effects can be increased when Propacetamol is combined with Formestane.	Approved
Prulifloxacin	The risk or severity of adverse effects can be increased when Formestane is combined with Prulifloxacin.	Investigational
PTC299	The risk or severity of adverse effects can be increased when PTC299 is combined with Formestane.	Investigational
Pyridostigmine	The risk or severity of adverse effects can be increased when Formestane is combined with Pyridostigmine.	Approved
Quinestrol	The serum concentration of Formestane can be increased when it is combined with Quinestrol.	Approved
Quinethazone	Formestane may increase the hypokalemic activities of Quinethazone.	Approved
Rabies virus inactivated antigen, A	The risk or severity of adverse effects can be increased when Formestane is combined with Rabies vaccine.	Approved
Rapacuronium	Rapacuronium may increase the adverse neuromuscular activities of Formestane.	Withdrawn
Resveratrol	The risk or severity of adverse effects can be increased when Resveratrol is combined with Formestane.	Experimental, Investigational
Rifabutin	The serum concentration of Formestane can be decreased when it is combined with Rifabutin.	Approved
Rifampicin	The serum concentration of Formestane can be decreased when it is combined with Rifampicin.	Approved
Rifapentine	The serum concentration of Formestane can be decreased when it is combined with Rifapentine.	Approved
Rindopepimut	The risk or severity of adverse effects can be increased when Formestane is combined with CDX-110.	Investigational
Ritonavir	The serum concentration of Formestane can be increased when it is combined with Ritonavir.	Approved, Investigational
Rivastigmine	The risk or severity of adverse effects can be increased when Formestane is combined with Rivastigmine.	Approved, Investigational
Rofecoxib	The risk or severity of adverse effects can be increased when Rofecoxib is combined with Formestane.	Investigational, Withdrawn
Rosoxacin	The risk or severity of adverse effects can be increased when Formestane is combined with Rosoxacin.	Approved
Salicylamide	The risk or severity of adverse effects can be increased when Salicylamide is combined with Formestane.	Approved
Salicylic acid	The risk or severity of adverse effects can be increased when Salicylic acid is combined with Formestane.	Approved, Vet Approved
Salsalate	The risk or severity of adverse effects can be increased when Salsalate is combined with Formestane.	Approved
Saquinavir	The serum concentration of Formestane can be increased when it is combined with Saquinavir.	Approved, Investigational
Secoisolariciresinol	The serum concentration of Formestane can be increased when it is combined with Secoisolariciresinol.	Investigational
Seratrodast	The risk or severity of adverse effects can be increased when Seratrodast is combined with Formestane.	Approved
Sparfloxacin	The risk or severity of adverse effects can be increased when Formestane is combined with Sparfloxacin.	Approved
SRP 299	The risk or severity of adverse effects can be increased when Formestane is combined with SRP 299.	Investigational
SRT501	The risk or severity of adverse effects can be increased when SRT501 is combined with Formestane.	Investigational
St. John's Wort	The serum concentration of Formestane can be decreased when it is combined with St. John's Wort.	Nutraceutical
Stanozolol	Formestane may increase the fluid retaining activities of Stanozolol.	Approved, Vet Approved
Sulfasalazine	The risk or severity of adverse effects can be increased when Sulfasalazine is combined with Formestane.	Approved
Sulindac	The risk or severity of adverse effects can be increased when Sulindac is combined with Formestane.	Approved
Suprofen	The risk or severity of adverse effects can be increased when Suprofen is combined with Formestane.	Approved, Withdrawn
Synthetic Conjugated Estrogens, A	The serum concentration of Formestane can be increased when it is combined with Synthetic Conjugated Estrogens, A.	Approved
Synthetic Conjugated Estrogens, B	The serum concentration of Formestane can be increased when it is combined with Synthetic Conjugated Estrogens, B.	Approved
Tacrine	The risk or severity of adverse effects can be increased when Formestane is combined with Tacrine.	Withdrawn
Telaprevir	The serum concentration of Telaprevir can be decreased when it is combined with Formestane.	Withdrawn
Telithromycin	The serum concentration of Formestane can be increased when it is combined with Telithromycin.	Approved
Temafloxacin	The risk or severity of adverse effects can be increased when Formestane is combined with Temafloxacin.	Withdrawn
Tenoxicam	The risk or severity of adverse effects can be increased when Tenoxicam is combined with Formestane.	Approved
Tepoxalin	The risk or severity of adverse effects can be increased when Tepoxalin is combined with Formestane.	Vet Approved
Teriflunomide	The risk or severity of adverse effects can be increased when Teriflunomide is combined with Formestane.	Approved
Testosterone	Formestane may increase the fluid retaining activities of Testosterone.	Approved, Investigational
TG4010	The risk or severity of adverse effects can be increased when Formestane is combined with TG4010.	Investigational
Tiaprofenic acid	The risk or severity of adverse effects can be increased when Tiaprofenic acid is combined with Formestane.	Approved
Tibolone	The serum concentration of Formestane can be increased when it is combined with Tibolone.	Approved
Tinoridine	The risk or severity of adverse effects can be increased when Tinoridine is combined with Formestane.	Investigational
Tolfenamic Acid	The risk or severity of adverse effects can be increased when Tolfenamic Acid is combined with Formestane.	Approved
Tolmetin	The risk or severity of adverse effects can be increased when Tolmetin is combined with Formestane.	Approved
Torasemide	Formestane may increase the hypokalemic activities of Torasemide.	Approved
Tranilast	The risk or severity of adverse effects can be increased when Tranilast is combined with Formestane.	Approved, Investigational
Trastuzumab	Trastuzumab may increase the cardiotoxic activities of Formestane.	Approved, Investigational
Trichlorfon	The risk or severity of adverse effects can be increased when Formestane is combined with Trichlorfon.	Vet Approved
Trichlormethiazide	Formestane may increase the hypokalemic activities of Trichlormethiazide.	Approved, Vet Approved
Trovafloxacin	The risk or severity of adverse effects can be increased when Formestane is combined with Trovafloxacin.	Approved, Withdrawn
Tubocurarine	The risk or severity of adverse effects can be increased when Formestane is combined with Tubocurarine.	Approved
Valdecoxib	The risk or severity of adverse effects can be increased when Valdecoxib is combined with Formestane.	Investigational, Withdrawn
Voriconazole	The serum concentration of Formestane can be increased when it is combined with Voriconazole.	Approved, Investigational
Warfarin	Formestane may increase the anticoagulant activities of Warfarin.	Approved
Zaltoprofen	The risk or severity of adverse effects can be increased when Zaltoprofen is combined with Formestane.	Approved
Zeranol	The serum concentration of Formestane can be increased when it is combined with Zeranol.	Vet Approved
Zileuton	The risk or severity of adverse effects can be increased when Zileuton is combined with Formestane.	Approved, Investigational, Withdrawn
Zomepirac	The risk or severity of adverse effects can be increased when Zomepirac is combined with Formestane.	Withdrawn

Food Interactions

Not Available

References

Synthesis Reference

Kohler, Maxie, et al. "Metabolism of 4-hydroxyandrostenedione and 4-hydroxytestosterone: Mass spectrometric identification of urinary metabolites." Steroids 72.3 (2007): 278-286.

General References

1. Perez Carrion R, Alberola Candel V, Calabresi F, Michel RT, Santos R, Delozier T, Goss P, Mauriac L, Feuilhade F, Freue M, et al.: Comparison of the selective aromatase inhibitor formestane with tamoxifen as first-line hormonal therapy in postmenopausal women with advanced breast cancer. Ann Oncol. 1994;5 Suppl 7:S19-24. [PubMed:7873457 ]
2. Kohler M, Parr MK, Opfermann G, Thevis M, Schlorer N, Marner FJ, Schanzer W: Metabolism of 4-hydroxyandrostenedione and 4-hydroxytestosterone: Mass spectrometric identification of urinary metabolites. Steroids. 2007 Mar;72(3):278-86. Epub 2007 Jan 17. [PubMed:17207827 ]
3. Lonning PE, Geisler J, Johannessen DC, Gschwind HP, Waldmeier F, Schneider W, Galli B, Winkler T, Blum W, Kriemler HP, Miller WR, Faigle JW: Pharmacokinetics and metabolism of formestane in breast cancer patients. J Steroid Biochem Mol Biol. 2001 Apr;77(1):39-47. [PubMed:11358673 ]
4. Murray R, Pitt P: Treatment of advanced breast cancer with formestane. Ann Oncol. 1994;5 Suppl 7:S11-3. [PubMed:7873455 ]
5. Vorobiof DA, Kleeberg UR, Perez-Carrion R, Dodwell DJ, Robertson JF, Calvo L, Dowsett M, Clack G: A randomized, open, parallel-group trial to compare the endocrine effects of oral anastrozole (Arimidex) with intramuscular formestane in postmenopausal women with advanced breast cancer. Ann Oncol. 1999 Oct;10(10):1219-25. [PubMed:10586340 ]

External Links

KEGG Drug

D07260

PubChem Compound

11273

PubChem Substance

175427144

ChemSpider

10799

BindingDB

225704

ChEBI

75172

ChEMBL

CHEMBL132530

Drugs.com

Drugs.com Drug Page

Wikipedia

Formestane

ATC Codes

L02BG02 — Formestane

• L02BG — Aromatase inhibitors
• L02B — HORMONE ANTAGONISTS AND RELATED AGENTS
• L02 — ENDOCRINE THERAPY
• L — ANTINEOPLASTIC AND IMMUNOMODULATING AGENTS

AHFS Codes

Not Available

PDB Entries

Not Available

FDA label

Not Available

MSDS

Download (279 KB)

Clinical Trials

Clinical Trials

Not Available

Pharmacoeconomics

Manufacturers

Not Available

Packagers

Not Available

Dosage forms

Form	Route	Strength
Liquid; powder, for solution	Intramuscular

Prices

Not Available

Patents

Not Available

Properties

State

Solid

Experimental Properties

Property	Value	Source
melting point (°C)	199 - 202	MSDS
water solubility	Insoluble	MSDS
logP	2.66	MSDS
pKa	9.31	MSDS

Predicted Properties

Property	Value	Source
Water Solubility	0.0578 mg/mL	ALOGPS
logP	2.57	ALOGPS
logP	3.41	ChemAxon
logS	-3.7	ALOGPS
pKa (Strongest Acidic)	9.21	ChemAxon
pKa (Strongest Basic)	-3.7	ChemAxon
Physiological Charge	0	ChemAxon
Hydrogen Acceptor Count	3	ChemAxon
Hydrogen Donor Count	1	ChemAxon
Polar Surface Area	54.37 Å2	ChemAxon
Rotatable Bond Count	0	ChemAxon
Refractivity	85.57 m3·mol-1	ChemAxon
Polarizability	34.07 Å3	ChemAxon
Number of Rings	4	ChemAxon
Bioavailability	1	ChemAxon
Rule of Five	Yes	ChemAxon
Ghose Filter	Yes	ChemAxon
Veber's Rule	No	ChemAxon
MDDR-like Rule	No	ChemAxon

Predicted ADMET features

Property	Value	Probability
Human Intestinal Absorption	+	1.0
Blood Brain Barrier	+	0.9628
Caco-2 permeable	+	0.8149
P-glycoprotein substrate	Substrate	0.6597
P-glycoprotein inhibitor I	Inhibitor	0.7113
P-glycoprotein inhibitor II	Non-inhibitor	0.8526
Renal organic cation transporter	Non-inhibitor	0.7227
CYP450 2C9 substrate	Non-substrate	0.8331
CYP450 2D6 substrate	Non-substrate	0.9308
CYP450 3A4 substrate	Substrate	0.753
CYP450 1A2 substrate	Non-inhibitor	0.9046
CYP450 2C9 inhibitor	Non-inhibitor	0.9443
CYP450 2D6 inhibitor	Non-inhibitor	0.941
CYP450 2C19 inhibitor	Non-inhibitor	0.9025
CYP450 3A4 inhibitor	Non-inhibitor	0.85
CYP450 inhibitory promiscuity	Low CYP Inhibitory Promiscuity	0.9027
Ames test	Non AMES toxic	0.9311
Carcinogenicity	Non-carcinogens	0.9537
Biodegradation	Not ready biodegradable	0.963
Rat acute toxicity	1.6135 LD50, mol/kg	Not applicable
hERG inhibition (predictor I)	Weak inhibitor	0.9479
hERG inhibition (predictor II)	Non-inhibitor	0.7566

ADMET data is predicted using admetSAR, a free tool for evaluating chemical ADMET properties. (23092397 )

Spectra

Mass Spec (NIST)

Not Available

Spectra

Spectrum	Spectrum Type	Splash Key
LC-MS/MS Spectrum - , positive	LC-MS/MS	splash10-01t9-2920000000-24696d73561fe3ce6680
Predicted LC-MS/MS Spectrum - 10V, Positive	Predicted LC-MS/MS	Not Available
Predicted LC-MS/MS Spectrum - 20V, Positive	Predicted LC-MS/MS	Not Available
Predicted LC-MS/MS Spectrum - 40V, Positive	Predicted LC-MS/MS	Not Available
Predicted LC-MS/MS Spectrum - 10V, Negative	Predicted LC-MS/MS	Not Available
Predicted LC-MS/MS Spectrum - 20V, Negative	Predicted LC-MS/MS	Not Available
Predicted LC-MS/MS Spectrum - 40V, Negative	Predicted LC-MS/MS	Not Available

Taxonomy

Description

This compound belongs to the class of chemical entities known as androgens and derivatives. These are 3-hydroxylated C19 steroid hormones. They are known to favor the development of masculine characteristics. They also show profound effects on scalp and body hair in humans.

Kingdom

Chemical entities

Super Class

Organic compounds

Class

Lipids and lipid-like molecules

Sub Class

Steroids and steroid derivatives

Direct Parent

Androgens and derivatives

Alternative Parents

Hydroxysteroids / 3-oxo delta-4-steroids / 17-oxosteroids / Delta-4-steroids / Cyclohexenones / Enols / Organic oxides / Hydrocarbon derivatives

Substituents

Androgen-skeleton / 3-oxo-delta-4-steroid / 3-oxosteroid / Oxosteroid / 17-oxosteroid / 4-hydroxysteroid / Hydroxysteroid / Delta-4-steroid / Cyclohexenone / Cyclic ketone

Molecular Framework

Aliphatic homopolycyclic compounds

External Descriptors

enol, 3-oxo Delta(4)-steroid, 17-oxo steroid, hydroxy steroid (CHEBI:75172 )