toremifene and Hot-Flashes

Selective estrogen receptor modulators (SERMs) are synthetic non-steroidal agents which have varying estrogen agonist and antagonist activities in different tissues, most likely due to the receptor conformation changes associated with that SERM's binding and the subsequent effect on transcription. Clinical trials aim to differentiate amongst SERMs on selected target tissues for use in postmenopausal women including effects on breast, bone, cardiovascular venous thrombosis risk, endometrium, vagina, vasomotor symptoms, and brain. This paper describes differences in clinical effects on selected target tissues of SERMs that are approved, discontinued or in development. FDA approved SERMs include tamoxifen and toremifene used for prevention and treatment of breast cancer, raloxifene approved for prevention and treatment of osteoporosis and prevention of invasive breast cancer, and ospemifene approved for treatment of dyspareunia from menopausal vaginal atrophy. The FDA approved first tissue selective estrogen complex (TSEC) a pairing of conjugated equine estrogens with the SERM, bazedoxifene. This pairing reduces the risk of endometrial hyperplasia that can occur with the estrogenic component of the TSEC without the need for a progestogen in women with a uterus. It also allows for the estrogenic benefits on relief of hot flashes and prevention of bone loss without stimulating the breast or the endometrium. In clinical practice, the tissue-selective actions of SERMs, alone or paired with estrogens, allow for individualization in meeting the treatment needs of postmenopausal women by providing targeted tissue effects. This article is part of a Special Issue entitled 'Menopause'.

Topics: Breast Neoplasms; Clinical Trials as Topic; Dyspareunia; Estrogens, Conjugated (USP); Female; Hot Flashes; Humans; Indoles; Osteoporosis; Osteoporosis, Postmenopausal; Postmenopause; Pyrrolidines; Raloxifene Hydrochloride; Receptors, Estrogen; Selective Estrogen Receptor Modulators; Tamoxifen; Tetrahydronaphthalenes; Toremifene

An association between CYP2D6 polymorphisms and tamoxifen (TAM) efficacy has not been confirmed, partly due to unreliable prediction of active metabolite exposure solely by CYP2D6 activity. The efficacy of TAM dose escalation appears limited in poor TAM metabolizers. Since the chlorine atom on the side chain of toremifene (TOR) prevents 4-hydroxylation by CYP2D6, its contribution to active conversion of TOR is minor. We examined the role of TOR and its dose escalation among poor TAM metabolizers.. The pharmacokinetics (PK) and pharmacogenomics (PGx) of TAM and TOR were studied. Correlation between PK and CYP2D6 inhibitor use, smoking status, and PGx were examined by regression analysis. For patients showing low endoxifen levels, an intra-patient dose escalation of TOR was conducted, and TOR was increased from 40 to 120 mg for ≥ 24 weeks with PK sampling. Total activity was calculated as the sum of the concentration of each active metabolite adjusted by their respective in vitro activities.. Fifty and 11 of the 273 participating patients had endoxifen levels < 15 and < 7.5 ng/mL, respectively. The CYP2D6 genotype was the major determinant for TAM activity (p < 0.01). Smoking status (p = 0.07) and the CYP2C19 phenotype (p = 0.07), but not the CYP2D6 genotype (p = 0.61), showed marginally significant effects on TOR activity. TOR activity increased significantly with dose escalation, even among poor TAM metabolizers, and was maintained for ≥ 24 weeks.. TOR might be a valid alternative to TAM in patients predicted to be poor TAM metabolizers.

Topics: Adult; Aged; Aged, 80 and over; Breast Neoplasms; Cytochrome P-450 CYP2C19; Cytochrome P-450 CYP2D6; Cytochrome P-450 CYP2D6 Inhibitors; Female; Genotype; Hot Flashes; Humans; Hydroxylation; Middle Aged; Phenotype; Polymorphism, Genetic; Selective Estrogen Receptor Modulators; Smoking; Tamoxifen; Toremifene

Toremifene (TOR), a selective estrogen receptor modulator (SERM), showed efficacy equivalent to Tamoxifen (TAM) in terms of the objective response rate, stable disease, time to progression and overall survival in patients with metastatic breast cancer (MBC). High-dose TOR is also effective for patients with TAM-resistant breast cancer. We tried to study retrospectively the efficacy and the safety of high-dose TOR treatment for patients with MBC in our hospital. Ten patients received TOR 120 mg daily. Most of the patients were treated with one or more endocrine agents before high-dose TOR. Objective response and clinical benefits were found in 3 patients (30%) and 7 patients (70%), respectively. Median time to progression and median overall survival were 9 months and 21.5 months, respectively. In our study,we found the efficacy for patients with hormone receptor negative, TAM resistance and aromatase inhibitor (AI)-resistance breast cancer. Adverse events induced by high-dose TOR treatment were tolerable. High-dose TOR may be one of the optional treatments for patients with MBC after TAM and AI treatment.

Topics: Aged; Antineoplastic Agents, Hormonal; Breast Neoplasms; Dose-Response Relationship, Drug; Drug Administration Schedule; Female; Hot Flashes; Humans; Middle Aged; Neoplasm Metastasis; Postmenopause; Receptors, Estrogen; Receptors, Progesterone; Retrospective Studies; Selective Estrogen Receptor Modulators; Survival Analysis; Toremifene

Topics: Antineoplastic Agents; Antineoplastic Agents, Hormonal; Aromatase Inhibitors; Breast Neoplasms; Clinical Trials as Topic; Drug Interactions; Enzyme Inhibitors; Estrogen Antagonists; Female; Hot Flashes; Humans; Letrozole; Middle Aged; Nausea; Nitriles; Postmenopause; Toremifene; Triazoles