Drug Groups

approved; investigational

Description

A first generation nonsteroidal selective estrogen receptor modulator (SERM) that is structurally related to tamoxifen. Like tamoxifen, it is an estrogen agonist for bone tissue and cholesterol metabolism but is antagonistic on mammary and uterine tissue. [PubChem]

Indication

For the treatment of metastatic breast cancer in postmenopausal women with estrogen receptor-positive or receptor-unknown tumors. Toremifene is currently under investigation as a preventative agent for prostate cancer in men with high-grade prostatic intraepithelial neoplasia and no evidence of prostate cancer.

Pharmacology

Toremifene is an antineoplastic hormonal agent primarily used in the treatment of advanced breast cancer. Toremifene is a nonsteroidal agent that has demonstrated potent antiestrogenic properties in animal test systems. The antiestrogenic effects may be related to its ability to compete with estrogen for binding sites in target tissues such as breast. Toremifene inhibits the induction of rat mammary carcinoma induced by dimethylbenzanthracene (DMBA) and causes the regression of already established DMBA-induced tumors. In this rat model, Toremifene appears to exert its antitumor effects by binding the estrogen receptors. In cytosols derived from human breast adenocarcinomas, Toremifene competes with estradiol for estrogen receptor protein.

Affected Organisms

Biotransformation

Hepatic. Mainly by CYP3A4 to N-demethyltoremifene, which exhibits antiestrogenic effects but has weak antitumor potency in vivo.

Absorption

Well absorbed

Half Life

5 days

Protein Binding

Toremifen is primarily bound to albumin (92%), 2% bound to α1-acid glycoprotein, and 6% bound to β1-globulin in the serum.

Elimination

Toremifene is extensively metabolized, principally by CYP3A4 to N-demethyltoremifene, which is also antiestrogenic but with weak in vivo antitumor potency.

Distribution

* 580 L

Clearance

* 5 L/h

References

External Links