droloxifene and idoxifene

During recent years the development of hormone therapy for the treatment breast neoplasms has seen, in addition to classic aspecific antiestrogens (AE) like tamoxifen (TAM) and to a lesser extent toremifen, a major development of new molecules divided into two groups: the first is the so-called selective estrogen receptor modulators (SERMs), the most important of which is Raloxifen, which mediate estrogen-agonist effects in some tissues and estrogen-antagonist effects in others; the second group includes the aromatase inhibitors (AI), important enzymes for peripheral estrogen conversion. Some studies compare or associate classic AE with the new SERMs and AI, both in adjuvant therapy and in treatment for advanced forms. Other trials assess the anti-osteoporotic activity of some SERMs which present concomitant inhibitory activity on the breast and endometrium.

Topics: Adult; Anastrozole; Antineoplastic Agents; Antineoplastic Agents, Hormonal; Aromatase Inhibitors; Breast Neoplasms; Clinical Trials as Topic; Clinical Trials, Phase III as Topic; Enzyme Inhibitors; Estrogen Antagonists; Female; Forecasting; Humans; Indoles; Letrozole; Middle Aged; Neoplasm Metastasis; Nitriles; Osteoporosis; Postmenopause; Raloxifene Hydrochloride; Selective Estrogen Receptor Modulators; Tamoxifen; Toremifene; Triazoles

Based on the data and clinical experience derived from tamoxifen usage, the properties of an ideal antiestrogen is described that could have applications as a breast cancer preventative agent, long-term adjuvant therdpy, or as a treatment for osteoporosis. Each of the new antiestrogens currently being tested is discussed in terms of laboratory development, toxicology, pharmacology, endocrinology, and clinical evaluation. And each new compound is assessed according to the properties of an ideal antiestrogen.. A review of all published reports was facilitated by the use of Medline computer searches.. Numerous compounds are being evaluated in clinical trials and can be categorized as triphenylethylenes or tamoxifen analogs, pure antiestrogens, and targeted antiestrogens. Several of these compounds may have fewer uterotropic properties and greater effects on maintaining bone density compared with tamoxifen; however, the clinical experience (ie, patient-years of treatment) with any of these compounds is minimal.. Although many of these compounds appear promising, further evaluation will be necessary to determine the role these compounds may serve as preventive agents, adjuvant therapies, treatments for advanced disease, or other medical indications such as osteoporosis.

Topics: Antineoplastic Agents, Hormonal; Bone Density; Drugs, Investigational; Estradiol; Estrogen Antagonists; Female; Fulvestrant; Humans; Osteoporosis, Postmenopausal; Piperidines; Raloxifene Hydrochloride; Tamoxifen; Toremifene

EM-652 exerts pure antiestrogenic activity in the mammary gland and endometrium, while tamoxifen, the antiestrogen most widely used for the treatment of breast cancer, exerts mixed antiestrogenic-estrogenic activity in these tissues. Our objective was to compare the agonistic and antagonistic effects of EM-652 with tamoxifen and 5 other antiestrogens on the growth of ZR-75-1 human breast xenografts in ovariectomized nude mice. During the 23 weeks of treatment at a daily oral dose of 50 microg, EM-652 was the only compound that decreased tumor size relative to pretreatment values, whereas the 6 other antiestrogens only decreased to various extents the progression rate stimulated by estrone. Under estrone stimulation, all groups of animals had more than 60% of their tumors in the progression category except for the EM-652-treated group, where only 7% of the tumors progressed. In the absence of estrone stimulation, progression was seen in 60%, 33%, 21% and 12% of tumors in the tamoxifen-, idoxifene-, toremifene- and raloxifene-treated groups, respectively, while only 4% of tumors progressed in the EM-652-treated group. The agonistic and antagonistic actions of each antiestrogen were also measured on endometrial epithelial cell thickness. Our present findings indicate that EM-652, in addition to being the most potent antiestrogen on human breast tumor growth, has no agonistic effect in breast and endometrial tissues. Since previous data have shown benefits of EM-652 on bone density and lipid profile, this compound could be an ideal candidate for chemoprevention of breast and uterine cancers, while protecting against osteoporosis and cardiovascular disease.

Topics: Animals; Breast Neoplasms; Cell Division; Cell Size; Cinnamates; Endometrium; Epithelial Cells; Estrogen Antagonists; Estrone; Female; Humans; Kinetics; Mice; Mice, Nude; Neoplasm Transplantation; Ovariectomy; Piperidines; Raloxifene Hydrochloride; Stilbenes; Tamoxifen; Toremifene; Tumor Cells, Cultured

Topics: Antineoplastic Agents, Hormonal; Breast Neoplasms; Clinical Trials as Topic; Drugs, Investigational; Estrogen Antagonists; Female; Humans; Lavandula; Male; Neoplasms; Oils, Volatile; Ovarian Neoplasms; Piperidines; Plant Oils; Plants, Medicinal; Prostatic Neoplasms; Raloxifene Hydrochloride; Retinoids; Tamoxifen; Toremifene