Serum placental protein 14: a novel marker of selective oestrogen receptor modulator action on the postmenopausal endometrium

Single and multiple ascending dose studies of a novel tissue-selective oestrogen receptor modulator, CHF 4227, in healthy postmenopausal women

AIMS

We evaluated the tolerability, adverse events profile, pharmacokinetics, and pharmacodynamics of CHF 4227, a new selective oestrogen receptor modulator (SERM), in healthy postmenopausal women.

METHODS

Two phase I studies were conducted according to a double-bind, placebo-controlled design. Subjects were randomized to receive six single (5-400 mg) or five multiple oral doses of CHF 4227 for 28 days (5-100 mg).

RESULTS

No vaginal bleeding and no changes in either endometrial thickness or the placenta protein 14 marker were found after 4 weeks of treatment. The compound did not induce negative effects on the fibrinolytic system. After 28 days of treatment, CHF 4227 decreased both total and LDL cholesterol concentrations (maximum decreases from baseline of 17.4% (95% CI 7.0, 27.7) and 27.6% (95% CI 9.0, 46.3), respectively). Decreases in both serum and urinary type-I C-terminal collagen telopeptide were also observed producing maximum changes of 40.6% (95% CI 29.5, 51.7), and 41.7% (95% CI 20.3, 56.8), respectively. CHF4227 (5 and 10 mg) induced near maximal oestrogen-like effects on bone markers and serum lipids without causing hot flushes. The pharmacokinetics of CHF 4227 were characterized by a slow absorption, a long elimination half-life (31-42 h after single administration) and dose linearity with respect to C(max) and AUC up to 100 mg.

CONCLUSIONS

CHF 4227 is a well-tolerated SERM when administered once daily for 28 days. It is potentially active on bone resorption and serum lipids, without affecting the endometrium and without worsening hot flushes. CHF 4227 is a promising agent for the treatment of several conditions in postmenopausal women.

Gene expression changes induced by estrogen and selective estrogen receptor modulators in primary-cultured human endometrial cells: signals that distinguish the human carcinogen tamoxifen

Tamoxifen has long been the endocrine treatment of choice for women with breast cancer and is now employed for prophylactic use in women at high risk from breast cancer. Other selective estrogen receptor modulators (SERMs), such as raloxifene, mimic some of tamoxifen's beneficial effects and, like tamoxifen, exhibit a complex mixture of organ-specific estrogen agonist and antagonistic properties. However, accompanying the positive effects of tamoxifen has been the emergence of evidence for an increased risk of endometrial cancer associated with its use. A more complete understanding of the mechanism(s) of SERM carcinogenicity and endometrial effects is therefore required. We have sought to compare and characterise the transcript profile of tamoxifen, raloxifene and the agonist estradiol in human endometrial cells. Using primary cultures of human endometria, to best emulate the in vivo responses in a manageable in vitro system, we have shown 230 significant changes in gene expression for epithelial cultures and 83 in stromal cultures, either specific to 17beta-estradiol, tamoxifen or raloxifene, or changed across more than one of the treatments. Considering the transcriptome as a whole, the endometrial responses to raloxifene or tamoxifen were more similar than either drug was to 17beta-estradiol. Treatment of endometrial cultures with tamoxifen resulted in the largest number of gene changes relative to control cultures and a high proportion of genes associated with regulation of gene transcription, cell-cycle control and signal transduction. Tamoxifen-specific changes that might point towards mechanisms for its proliferative response in the endometrium included changes in retinoblastoma and c-myc binding proteins, the APCL, dihydrofolate reductase (DHFR) and E2F1 genes and other transcription factors. Tamoxifen was also found to give rise to the highest number of gene expression changes common to those that characterise malignant endometria. It is anticipated that this study will provide leads for further and more focused investigation into SERM carcinogenicity.