piperidines and levormeloxifene

Selective estrogen receptor modulators (SERMs) are structurally diverse compounds that bind to estrogen receptors (ER) and elicit agonist or antagonist responses depending on the target tissue and hormonal milieu. They are being evaluated primarily for conditions associated with aging, including hormone-responsive cancer, osteoporosis and cardiovascular disease. Several SERMs are marketed or are in clinical development, including triphenylethylenes (tamoxifen and its derivatives: toremifene, droloxifene and idoxifene), chromans (levormeloxifene), benzothiophenes (raloxifene, LY353381) and naphthalenes (CP336,156). Tamoxifen and toremifene, both used to treat advanced breast cancer, also have beneficial effects on bone mineral density and serum lipids in postmenopausal women. Tamoxifen was recently shown to decrease the risk of invasive breast cancer in women at high risk. Unfortunately, both drugs also have stimulatory effects on the endometrium. Raloxifene, used for prevention of postmenopausal osteoporosis and fragility fractures, also has favourable effects on bone mineral density, serum lipids and the incidence of invasive breast cancer in postmenopausal women but does not stimulate the endometrium. Like replacement estrogens, SERMs increase the risk of venous thromboembolism. SERMs offer post-menopausal women many of the advantages of estrogen replacement while mitigating some of the disadvantages, particularly the concern over breast cancer. Newer SERMs, exemplified by raloxifene, also eliminate the concerns over endometrial stimulation that were not addressed by first generation SERMs. The clinical success of SERMs has set the stage for a variety of drug therapies based on selective modulation of nuclear receptor activity.

Topics: Estrogen Antagonists; Estrogen Replacement Therapy; Female; Humans; Piperidines; Postmenopause; Pyrrolidines; Raloxifene Hydrochloride; Receptors, Estrogen; Tamoxifen; Toremifene

We have discovered a new, nonsteroidal, estrogen agonist/antagonist, 3-phenyl-4-[[4-[2-(1-piperidinyl)ethoxy]phenyl] methyl]-2H-1-benzopyran-7-ol (CHF 4056). The aim of this study was to determine the effects of CHF 4056 on a series of parameters (body weight, uteri, serum cholesterol, and bones) that were previously shown to be sensitive to estrogens and to selective estrogen receptor modulators (SERMs). CHF 4056 is a benzopyran derivative that binds with high affinity to the human estrogen receptors alpha and beta (dissociation constant K(i) of 0.041 and 0.157 nM, respectively). In immature rats, CHF 4056 induced a full estrogen antagonism (half-maximal efficacious dose = 0.33 mg/kg x day p.o.) coupled with a lack of uterine stimulatory activity, whereas the structurally related SERM levormeloxifene demonstrated a maximal partial agonist effect of approximately 65% that of 17alpha-ethynyl estradiol (EE2). In ovariectomized (OVX) rats, CHF 4056 (0.1-1 mg/kg x day p.o. for 4 weeks) significantly reduced OVX-induced bone loss in the lumbar spine L1-4 and OVX-induced increase in serum osteocalcin. These protective effects on bone tissue were comparable with those of 0.1 mg/kg x day EE2. In the same experimental conditions, serum cholesterol was significantly lower in the CHF 4056-treated animals, compared with vehicle-treated OVX rats. In line with the results observed in immature rats, also in OVX rats CHF 4056 diverged dramatically from EE2 and levormeloxifene in its lack of significant estrogenic effects on uterine tissue. In conclusion, CHF 4056 is a new SERM that produces beneficial effects on bone and cholesterol levels, while maintaining antagonist effects on the uterus.

Topics: Animals; Benzopyrans; Bone Density; Cholesterol; Dose-Response Relationship, Drug; Eosinophil Peroxidase; Estradiol Congeners; Estrogen Antagonists; Estrogen Receptor alpha; Estrogen Receptor beta; Ethinyl Estradiol; Female; Humans; In Vitro Techniques; Ovariectomy; Peroxidases; Piperidines; Pyrrolidines; Rats; Rats, Sprague-Dawley; Receptors, Estrogen; Selective Estrogen Receptor Modulators; Uterus