4-hydroxytamoxifen

Afimoxifene

Clinical data
Routes of administration	Topical (gel)
Identifiers
IUPAC name (Z)-4-(1-(4-(2-(dimethylamino)ethoxy)phenyl)-2-phenylbut-1-enyl)phenol
Synonyms	4-Hydroxytamoxifen
CAS Number	68392-35-8 N
PubChem CID	449459
ChemSpider	395987 Y
UNII	17197F0KYM
KEGG	D06551 Y
ChEMBL	CHEMBL489 Y
ECHA InfoCard	100.155.464
Chemical and physical data
Formula	C26H29NO2
Molar mass	387.5139 g/mol
3D model (JSmol)	Interactive image
SMILES CC\C(c1ccccc1)=C(c2ccc(OCCN(C)C)cc2)/c3ccc(O)cc3
InChI InChI=1S/C26H29NO2/c1-4-25(20-8-6-5-7-9-20)26(21-10-14-23(28)15-11-21)22-12-16-24(17-13-22)29-19-18-27(2)3/h5-17,28H,4,18-19H2,1-3H3/b26-25- Y Key:TXUZVZSFRXZGTL-QPLCGJKRSA-N Y
NY (what is this?)

Afimoxifene, also known as 4-hydroxytamoxifen (4-OHT, 4-HT, OHTAM, others), is a selective estrogen receptor modulator (SERM) of the triphenylethylene group and the major active metabolite of tamoxifen. The drug is under development by Ascend Therapeutics under the tentative trademark TamoGel as a topical gel for the treatment of cyclical mastalgia (breast pain). It has completed a phase II clinical trial for this indication, but further studies are required before afimoxifene can be approved for this indication and marketed.

A study in France on 55 women showed that rubbing afimoxifene on the skin was as effective as oral tamoxifen at slowing breast cancer growth. A United States trial will compare 6 weeks use before breast cancer surgery. Skin application can reduce systemic levels by a factor of nine and this is expected to reduce the unpleasant side-effects of tamoxifen.

In addition to its antiestrogenic and estrogenic activity, afimoxifene has been found to act as an antagonist of the estrogen-related receptors (ERRs) ERRβ and ERRγ.