Afimoxifene, also known as 4-hydroxytamoxifen (4-OHT) and by its tentative brand name TamoGel, is a
selective estrogen receptor modulator
Selective estrogen receptor modulators (SERMs), also known as estrogen receptor agonists/antagonists (ERAAs), are a class of drugs that act on estrogen receptors (ERs). Compared to pure ER agonists–antagonists (e.g., full agonists and silent ...
(SERM) of the
triphenylethylene
Triphenylethylene (TPE) is the organic compound with the formula . It is a colorless solid. Synthesis and reactions
The compound is prepared in two steps from benzophenone via the intermediacy of 1,2,2-triphenylethanol. Triphenylethylene reacts ...
tamoxifen
Tamoxifen, sold under the brand name Nolvadex among others, is a selective estrogen receptor modulator used to prevent breast cancer in women and men. It is also being studied for other types of cancer. It has been used for Albright syndrome ...
. The drug is under development under the tentative brand name TamoGel as a topical gel for the treatment of
hyperplasia
Hyperplasia (from ancient Greek ὑπέρ ''huper'' 'over' + πλάσις ''plasis'' 'formation'), or hypergenesis, is an enlargement of an organ or tissue caused by an increase in the amount of Tissue (biology), organic tissue that results from ...
of the
breast
The breasts are two prominences located on the upper ventral region of the torso among humans and other primates. Both sexes develop breasts from the same embryology, embryological tissues. The relative size and development of the breasts is ...
clinical trial
Clinical trials are prospective biomedical or behavioral research studies on human subject research, human participants designed to answer specific questions about biomedical or behavioral interventions, including new treatments (such as novel v ...
for cyclical mastalgia, but further studies are required before afimoxifene can be approved for this indication and marketed.
Afimoxifene is a SERM and hence acts as a tissue-selectiveagonist–antagonist of the
estrogen receptor
Estrogen receptors (ERs) are proteins found in cell (biology), cells that function as receptor (biochemistry), receptors for the hormone estrogen (17β-estradiol). There are two main classes of ERs. The first includes the intracellular estrogen ...
s
ERα
Estrogen receptor alpha (ERα), also known as NR3A1 (nuclear receptor subfamily 3, group A, member 1), is one of two main types of estrogen receptor, a nuclear receptor (mainly found as a chromatin-binding protein)
that is activated by the se ...
and
ERβ
Estrogen receptor beta (ERβ) also known as NR3A2 (nuclear receptor subfamily 3, group A, member 2) is one of two main types of estrogen receptor—a nuclear receptor which is activated by the sex hormone estrogen. In humans ERβ is encoded by t ...
with mixed
estrogen
Estrogen (also spelled oestrogen in British English; see spelling differences) is a category of sex hormone responsible for the development and regulation of the female reproductive system and secondary sex characteristics. There are three ...
agonist
An agonist is a chemical that activates a Receptor (biochemistry), receptor to produce a biological response. Receptors are Cell (biology), cellular proteins whose activation causes the cell to modify what it is currently doing. In contrast, an R ...
affinity
Affinity may refer to:
Commerce, finance and law
* Affinity (law), kinship by marriage
* Affinity analysis, a market research and business management technique
* Affinity Credit Union, a Saskatchewan-based credit union
* Affinity Equity Pa ...
estradiol
Estradiol (E2), also called oestrogen, oestradiol, is an estrogen steroid hormone and the major female sex hormone. It is involved in the regulation of female reproductive cycles such as estrous and menstrual cycles. Estradiol is responsible ...
). In addition to its estrogenic and antiestrogenic activity, afimoxifene has been found to act as an
antagonist
An antagonist is a character in a story who is presented as the main enemy or rival of the protagonist and is often depicted as a villain.estrogen-related receptors (ERRs) ERRβ and ERRγ.