High intratumoral dihydrotestosterone is associated with antiandrogen resistance in VCaP prostate cancer xenografts in castrated mice.

Antiandrogen treatment resistance is a major clinical concern in castration-resistant prostate cancer (CRPC) treatment. Using xenografts of VCaP cells we showed that growth of antiandrogen resistant CRPC tumors were characterized by a higher intratumor dihydrotestosterone (DHT) concentration than that of treatment responsive tumors. Furthermore, the slow tumor growth after adrenalectomy was associated with a low intratumor DHT concentration. Reactivation of androgen signaling in enzalutamide-resistant tumors was further shown by the expression of several androgen-dependent genes. The data indicate that intratumor DHT concentration and expression of several androgen-dependent genes in CRPC lesions is an indication of enzalutamide treatment resistance and an indication of the need for further androgen blockade. The presence of an androgen synthesis, independent of CYP17A1 activity, has been shown to exist in prostate cancer cells, and thus, novel androgen synthesis inhibitors are needed for the treatment of enzalutamide-resistant CRPC tumors that do not respond to abiraterone.

Phase I/IIa, open-label, multicentre study to evaluate the optimal dosing and safety of ODM-203 in patients with advanced or metastatic solid tumours.

BACKGROUND: Genetic alterations in fibroblast growth factor receptor (FGFR) and vascular endothelial growth factor receptor (VEGFR) signalling are observed in various tumours. We report a first-in-human phase I/IIa trial evaluating tolerability, pharmacokinetics and preliminary antitumour activity of ODM-203, a novel FGFR and VEGFR inhibitor. METHODS: Open-label, non-randomised, multicentre, phase I/IIa dose escalation and expansion study in patients with advanced or metastatic solid tumours. RESULTS: Overall, 84 patients received treatment; optimal tablet dose was found to be 400 mg/day with food. All patients experienced at least one adverse event; the majority (89.2%) were grade 1 or 2% and 70.4% were considered treatment related. The most commonly reported events were bilirubin increase-related events (75%) and diarrhoea (50%).Overall response rate was 9.2% and median progression-free survival was 16.1 and 12.4 weeks for patients with aberrant or non-aberrant FGFR tumours. Median time on treatment was 10.1 weeks for all patients and 14.5 weeks for patients who received 400 mg tablets. CONCLUSION: This study suggests ODM-203 400 mg/day results in sufficient plasma concentrations and acceptable tolerability in most patients. Preliminary signs of therapeutic activity of ODM-203 in patients with solid tumours was observed. TRIAL REGISTRATION NUMBER: NCT02264418.

ODM-204, a Novel Dual Inhibitor of CYP17A1 and Androgen Receptor: Early Results from Phase I Dose Escalation in Men with Castration-resistant Prostate Cancer.

BACKGROUND: Most prostate cancer patients develop castration-resistant prostate cancer (CRPC) after androgen deprivation therapy treatment. CRPC growth is mediated mostly by androgen receptor signalling driven by primary androgens synthesised largely by the CYP17A1 enzyme. OBJECTIVE: To evaluate the safety profile and dose-limiting toxicities of ODM-204. DESIGN, SETTING, AND PARTICIPANTS: In this open, uncontrolled, nonrandomised, multicentre, tolerability and pharmacokinetic first-in-man phase I dose escalation study, patients with metastatic CRPC were randomised to receive ODM-204 in sequential cohorts of five dose levels (ie, 50, 100, 200, 300, and 500mg twice daily) concomitantly with prednisone. INTERVENTION: ODM-204, a novel, orally administered, investigational, nonsteroidal dual inhibitor of CYP17A1 and androgen receptor. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: ODM-204 plasma concentrations, serum testosterone, and prostate-specific antigen (PSA) levels were evaluated and imaging of lesions was performed. RESULTS AND LIMITATIONS: Of the 23 patients enrolled into the study, 60.9% experienced mild adverse effects considered to be related to the study treatment, which were fatigue, increased/decreased appetite, nausea, asthenia, diarrhoea, and weight decrease. ODM-204 area under the curve (AUC0-12) values increased dose dependently until the 300mg dose. The AUC was lower on day 8 after repeated dosing compared with day 1 from the 200mg dose upwards. Decreases in testosterone levels were seen with ODM-204 treatment confirming androgen deprivation. Of the patients, 13% also demonstrated a >50% decrease in PSA at week 12 and continued ODM-204 treatment for over a year. CONCLUSIONS: ODM-204 was well tolerated up to the highest evaluated dose. There were decreases in both testosterone and PSA levels, suggesting preliminary antitumour activity in the treatment of CRPC. The pharmacokinetic properties of the molecule, however, prevent further development. PATIENT SUMMARY: This study looked at the safety of ODM-204, a novel dual inhibitor of CYP17A1 and the androgen receptor, in castration-resistant prostate cancer patients. ODM-204 treatment was found to be well tolerated, and it also reduced both serum testosterone and prostate-specific antigen levels, but the properties of the molecule prevent further development.

Discovery and development of ODM-204: A Novel nonsteroidal compound for the treatment of castration-resistant prostate cancer by blocking the androgen receptor and inhibiting CYP17A1.

We report the discovery of a novel nonsteroidal dual-action compound, ODM-204, that holds promise for treating patients with castration-resistant prostate cancer (CRPC), an advanced form of prostate cancer characterised by high androgen receptor (AR) expression and persistent activation of the AR signaling axis by residual tissue androgens. For ODM-204, has a dual mechanism of action. The compound is anticipated to efficiently dampen androgenic stimuli in the body by inhibiting CYP17A1, the prerequisite enzyme for the formation of dihydrotestosterone (DHT) and testosterone (T), and by blocking AR with high affinity and specificity. In our study, ODM-204 inhibited the proliferation of androgen-dependent VCaP and LNCaP cells in vitro and reduced significantly tumour growth in a murine VCaP xenograft model in vivo. Intriguingly, after a single oral dose of 10-30 mg/kg, ODM-204 dose-dependently inhibited adrenal and testicular steroid production in sexually mature male cynomolgus monkeys. Similar results were obtained in human chorionic gonadotropin-treated male rats. In rats, leuprolide acetate-mediated (LHRH agonist) suppression of the circulating testosterone levels and decrease in weights of androgen-sensitive organs was significantly and dose-dependently potentiated by the co-administration of ODM-204. ODM-204 was well tolerated in both rodents and primates. Based on our data, ODM-204 could provide an effective therapeutic option for men with CRPC.

Adrenals Contribute to Growth of Castration-Resistant VCaP Prostate Cancer Xenografts.

The role of adrenal androgens as drivers for castration-resistant prostate cancer (CRPC) growth in humans is generally accepted; however, the value of preclinical mouse models of CRPC is debatable, because mouse adrenals do not produce steroids activating the androgen receptor. In this study, we confirmed the expression of enzymes essential for de novo synthesis of androgens in mouse adrenals, with high intratissue concentration of progesterone (P4) and moderate levels of androgens, such as androstenedione, testosterone, and dihydrotestosterone, in the adrenal glands of both intact and orchectomized (ORX) mice. ORX alone had no effect on serum P4 concentration, whereas orchectomized and adrenalectomized (ORX + ADX) resulted in a significant decrease in serum P4 and in a further reduction in the low levels of serum androgens (androstenedione, testosterone, and dihydrotestosterone), measured by mass spectrometry. In line with this, the serum prostate-specific antigen and growth of VCaP xenografts in mice after ORX + ADX were markedly reduced compared with ORX alone, and the growth difference was not abolished by a glucocorticoid treatment. Moreover, ORX + ADX altered the androgen-dependent gene expression in the tumors, similar to that recently shown for the enzalutamide treatment. These data indicate that in contrast to the current view, and similar to humans, mouse adrenals synthesize significant amounts of steroids that contribute to the androgen receptor-dependent growth of CRPC.

Safety and Antitumour Activity of ODM-201 (BAY-1841788) in Chemotherapy-naïve and CYP17 Inhibitor-naïve Patients: Follow-up from the ARADES and ARAFOR Trials.

BACKGROUND: ODM-201, a new androgen receptor antagonist for treatment of metastatic castration-resistant prostate cancer (mCRPC), demonstrated antitumour activity and acceptable tolerability in phase 1/2 trials. OBJECTIVE: To determine the antitumour activity and safety profile of extended treatment with ODM-201 in men with mCRPC. DESIGN, SETTING, AND PARTICIPANTS: ARADES and ARAFOR trials with ODM-201 enrolled chemotherapy-naïve and CYP17 inhibitor (CYP17i)-naïve mCRPC patients. Both trials had extended follow-up. Here we report results for chemotherapy-naïve and CYP17i-naïve patients from both trials (data cutoff October 2014 for ARADES and April 2015 for ARAFOR) after extended follow-up. INTERVENTION: A total of 41 chemotherapy-naïve and CYP17i-naïve patients received oral ODM-201 twice daily (total daily dose of 1200, 1400 or 1800mg). OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Antitumour activity was assessed in terms of prostate-specific antigen (PSA) declines and PSA/radiographic progression. Safety was assessed until disease progression and/or drug discontinuation due to any intolerable adverse event (AE). RESULTS AND LIMITATIONS: ODM-201 safety data after a median treatment time of 13.5 mo (95% confidence interval [CI] 9.7-15.6, interquartile range [IQR] 7.5-22.0) were similar to those reported in the main ARADES and ARAFOR trials. The overall AE incidence was 80.5% (n=33/41), with 58.5% (n=24/41) of patients experiencing only grade 1-2 AEs. The most common AEs were fatigue, back pain, diarrhoea, nausea, and pain in extremity. The median times to PSA and radiological progression were 12.4 mo (95% CI 6.3-18.2, IQR 5.5-22.0) and 15.3 mo (95% CI 9.5-not reached [NR], IQR 6.3-NR), respectively. CONCLUSIONS: Extended treatment with ODM-201 (1200-1800mg/d) was well tolerated, with no new safety concerns, and provided evidence of sustained antitumour activity in chemotherapy-naïve and CYP17i-naïve patients with mCRPC. PATIENT SUMMARY: Prolonged treatment with high doses of ODM-201 was well tolerated and provided long-lasting disease control in patients with mCRPC. ODM-201 represents a therapeutic treatment option for mCRPC. The ARAFOR trial (including the follow-up stage) and the follow-up component of the ARADES trial are registered with ClinicalTrials.gov as trial numbers NCT01784757 and NCT01429064.

Safety and Antitumour Activity of ODM-201 (BAY-1841788) in Castration-resistant, CYP17 Inhibitor-naïve Prostate Cancer: Results from Extended Follow-up of the ARADES Trial.

BACKGROUND: Patients with castration-resistant prostate cancer (CRPC) had extended responses to the androgen receptor antagonist ODM-201, in phase 1/2 studies. OBJECTIVE: To evaluate the safety and antitumour activity of prolonged ODM-201 treatment in patients with CRPC. DESIGN, SETTING, AND PARTICIPANTS: The ARADES trial was a multicentre phase 1 (dose escalation) and phase 2 (dose expansion) trial; 134 patients with CRPC were stratified by previous chemotherapy to receive ODM-201. This paper reports extended follow-up in CYP17 inhibitor (CYP17i)-naïve patients. INTERVENTION: Patients (n=77) received oral ODM-201 twice daily at daily doses of 200-1800mg. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Safety, measured as the occurrence of adverse events (AEs), prostate-specific antigen (PSA), and radiographic progression. RESULTS AND LIMITATIONS: The safety profile of extended ODM-201 treatment (median treatment duration 8.2 mo, 95% confidence interval [CI] 5.6-11.0) was consistent with that reported at the time of the original data cutoff in the main ARADES trial, with no unexpected safety concerns over time. The majority of AEs (61.1%) were mild (grade 1); the most common AE was fatigue/asthenia (35.1% of patients), with no clear relationship to ODM-201. Median time to PSA progression was 25.2 mo (95% CI 11.3-25.2) for chemotherapy-naïve men and not reached (NR; 95% CI 5.5-NR) for chemotherapy-pretreated patients; a trend for improved antitumour response was observed for chemotherapy-naïve patients. The median time to radiographic progression was longer for chemotherapy-naïve (14.0 mo, 95% CI 8.1-33.3) than for chemotherapy-pretreated (7.2 mo, 95% CI 2.7-11.0) patients. CONCLUSIONS: Prolonged exposure to ODM-201 was well tolerated, with no additional safety concerns; disease suppression was sustained, especially in chemotherapy-naïve patients. These data support further development of ODM-201 in men with CYP17i-naïve CRPC. PATIENT SUMMARY: Extended ODM-201 therapy was well tolerated, with beneficial antitumour activity in men with advanced prostate cancer, indicating that ODM-201 may represent a new active treatment for men with CRPC. This extension trial is registered at ClinicalTrials.gov (www.clinicaltrials.gov) under identification number NCT01429064.

Bone Scan Index and Progression-free Survival Data for Progressive Metastatic Castration-resistant Prostate Cancer Patients Who Received ODM-201 in the ARADES Multicentre Study.

BACKGROUND: ODM-201, a new-generation androgen receptor inhibitor, has shown clinical efficacy in prostate cancer (PCa). Quantitative methods are needed to accurately assess changes in bone as a measurement of treatment response. The Bone Scan Index (BSI) reflects the percentage of skeletal mass a given tumour affects. OBJECTIVE: To evaluate the predictive value of the BSI in metastatic castration-resistant PCa (mCRPC) patients undergoing treatment with ODM-201. DESIGN, SETTING, AND PARTICIPANTS: From a total of 134 mCRPC patients who participated in the Activity and Safety of ODM-201 in Patients with Progressive Metastatic Castration-resistant Prostate Cancer clinical trial and received ODM-201, we retrospectively selected all those patients who had bone scan image data of sufficient quality to allow for both baseline and 12-wk follow-up BSI-assessments (n=47). We used the automated EXINI bone BSI software (EXINI Diagnostics AB, Lund, Sweden) to obtain BSI data. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: We used the Cox proportional hazards model and Kaplan-Meier estimates to investigate the association among BSI, traditional clinical parameters, disease progression, and radiographic progression-free survival (rPFS). RESULTS AND LIMITATIONS: In the BSI assessments, at follow-up, patients who had a decrease or at most a 20% increase from BSI baseline had a significantly longer time to progression in bone (median not reached vs 23 wk, hazard ratio [HR]: 0.20; 95% confidence interval [CI], 0.07-0.58; p=0.003) and rPFS (median: 50 wk vs 14 wk; HR: 0.35; 95% CI, 0.17-0.74; p=0.006) than those who had a BSI increase >20% during treatment. CONCLUSIONS: The on-treatment change in BSI was significantly associated with rPFS in mCRPC patients, and an increase >20% in BSI predicted reduced rPFS. BSI for quantification of bone metastases may be a valuable complementary method for evaluation of treatment response in mCRPC patients. PATIENT SUMMARY: An increase in Bone Scan Index (BSI) was associated with shorter time to disease progression in patients treated with ODM-201. BSI may be a valuable method of complementing treatment response evaluation in patients with advanced prostate cancer.

Toremifene in the treatment of breast cancer.

Although more widespread screening and routine adjuvant therapy has improved the outcome for breast cancer patients in recent years, there remains considerable scope for improving the efficacy, safety and tolerability of adjuvant therapy in the early stage disease and the treatment of advanced disease. Toremifene is a selective estrogen receptor modifier (SERM) that has been widely used for decades in hormone receptor positive breast cancer both in early and late stage disease. Its efficacy has been well established in nine prospective randomized phase III trials compared to tamoxifen involving more than 5500 patients, as well as in several large uncontrolled and non-randomized studies. Although most studies show therapeutic equivalence between the two SERMs, some show an advantage for toremifene. Several meta-analyses have also confirmed that the efficacy of toremifene is at least as good as that of tamoxifen. In terms of safety and tolerability toremifene is broadly similar to tamoxifen although there is some evidence that toremifene is less likely to cause uterine neoplasms, serious vascular events and it has a more positive effect on serum lipids than does tamoxifen. Toremifene is therefore effective and safe in the treatment of breast cancer. It provides not only a useful therapeutic alternative to tamoxifen, but may bring specific benefits.

Activity and safety of ODM-201 in patients with progressive metastatic castration-resistant prostate cancer (ARADES): an open-label phase 1 dose-escalation and randomised phase 2 dose expansion trial.

BACKGROUND: ODM-201 is a novel androgen receptor (AR) inhibitor designed to block the growth of prostate cancer cells through high-affinity binding to the AR and inhibition of AR nuclear translocation. This trial assessed ODM-201's safety, pharmacokinetics, and activity in men with metastatic castration-resistant prostate cancer. METHODS: The ARADES trial is an open-label phase 1-2 trial undertaken in 23 hospitals across Europe and USA with ongoing long-term follow-up. Men with progressive metastatic castration-resistant prostate cancer, who had castrate concentrations of testosterone and an Eastern Cooperative Oncology Group score of 0-1 were enrolled. In the phase 1 part of the trial, patients were given oral ODM-201 at a starting daily dose of 200 mg, which was increased to 400 mg, 600 mg, 1000 mg, 1400 mg, and 1800 mg. In phase 2, patients were randomly assigned centrally and stratified by previous chemotherapy and treatment with CPY17 inhibitors, to receive one of three daily doses of ODM-201 (200 mg, 400 mg, and 1400 mg). The primary endpoint in phase 1 was safety and tolerability, whereas in phase 2 it was the proportion of patients with a PSA response (50% or greater decrease in serum PSA) at week 12. All analyses included patients who had received at least one dose of ODM-201. This trial is registered with ClinicalTrials.gov, number NCT01317641, and NCT01429064 for the follow-up after 12 weeks. FINDINGS: We enrolled patients between April 5, 2011, and March 12, 2013. In phase 1, 24 patients were enrolled to six sequential cohorts of three to six patients and received a daily dose of ODM-201, 200-1800 mg. No dose-limiting toxic effects were reported and the maximum tolerated dose was not reached. In phase 1, three patients reported eight adverse events of grade 3 (fracture, muscle injury, laceration, paralytic ileus, pain, presyncope, urinary retention, and vomiting) and one patient had a grade 4 adverse event (lymphoedema). None of the grade 3-4 adverse events were deemed to be related to ODM-201. Of the phase 1 patients, the four who received 200 mg, seven who received 400 mg, and three who received 1400 mg entered the phase 2 part of the trial. In addition to these patients, 110 were randomly assigned to three groups: 200 mg (n=38), 400 mg (n=37), and 1400 mg (n=35). For these patients, the most common treatment-emergent adverse events were fatigue or asthenia (15 [12%] of 124 patients), hot flush (six [5%]), and decreased appetite (five [4%]). One patient (<1%) had a grade 3 treatment-emergent adverse event (fatigue); no patients had a treatment-emergent grade 4 adverse event. 38 patients who received 200 mg, 39 who received 400 mg, and 33 who received 1400 mg were assessable for PSA response at 12 weeks. 11 (29%) patients in the 200 mg group, 13 (33%) in the 400 mg group, and 11 (33%) in the 1400 mg group had a PSA response at 12 weeks. INTERPRETATION: Our results suggest that ODM-201 monotherapy in men with progressive metastatic castration-resistant prostate cancer provides disease suppression and that ODM-201 has a favourable safety profile. These findings support further investigation of clinical responses with ODM-201 in men with castration-resistant prostate cancer. FUNDING: Orion Corporation Orion Pharma, Endo Pharmaceuticals Inc.

Implementation of a Bayesian design in a dose-escalation study of an experimental agent in healthy volunteers.

Bayesian decision procedures have recently been developed for dose escalation in phase I clinical trials concerning pharmacokinetic responses observed in healthy volunteers. This article describes how that general methodology was extended and evaluated for implementation in a specific phase I trial of a novel compound. At the time of writing, the study is ongoing, and it will be some time before the sponsor will wish to put the results into the public domain. This article is an account of how the study was designed in a way that should prove to be safe, accurate, and efficient whatever the true nature of the compound. The study involves the observation of two pharmacokinetic endpoints relating to the plasma concentration of the compound itself and of a metabolite as well as a safety endpoint relating to the occurrence of adverse events. Construction of the design and its evaluation via simulation are presented.

Continuous combined hormone replacement therapy relieves climacteric symptoms and improves health-related quality of life in early postmenopausal women.

OBJECTIVE: Hormone replacement therapy (HRT) relieves menopausal symptoms but its effect on health related quality of life (HRQoL) is uncertain. The aim of this study was to assess the effect of three dose regimens of continuous combined HRT, consisting of estradiol valerate (E2V) and medroxyprogesterone acetate (MPA) on HRQoL in early postmenopausal women (last menstrual period 1-3 years before study entry). STUDY DESIGN: This was a 52-week, randomized, double-blind, multinational study comparing E2V (1 mg or 2 mg) plus MPA (2.5 mg or 5 mg) in different dose combinations. The intention-to-treat population comprised 459 women (average age 51.5 years). MAIN OUTCOME MEASURES: HRQoL was assessed by the Women's Health Questionnaire (WHQ), the 15D Questionnaire and a visual analogue scale (VAS). RESULTS: There were improvements on eight of the nine domains of the WHQ with all dose regimens during the first 12 weeks (P<0.0001) and an improvement in the remaining domain (menstrual symptoms) with the lower-dose regimens (P<0.05). These initial improvements in HRQoL were then maintained or augmented over the remainder of the study (P<0.0001 for change from baseline at 52 weeks for all domains and dose regimens). Mean 15D total score had improved meaningfully and significantly by 12 weeks (P<0.0001 versus baseline) in all treatment groups and this improvement was maintained thereafter. This improvement in 15D total score was most marked among previous non-users of HRT (P<0.05 versus previous users). VAS scores recorded significant (P<0.05) reductions in hot flushes, sweating and sleep disturbances in all groups after week 1 and highly significant (P<0.0001) relief of all climacteric symptoms at week 52. CONCLUSION: Continuous combined HRT was associated with pronounced improvement of vasomotor symptoms and HRQoL in this population of early postmenopausal women.

No increased risk of endometrial hyperplasia with fixed long-cycle oestrogen-progestogen therapy after five years.

OBJECTIVE: The aim of this study was to evaluate the long-term endometrial safety of long-cycle sequential oestrogen-progestogen hormone replacement therapy (HRT). STUDY DESIGN: A prospective, longitudinal, single group study was undertaken in postmenopausal women, aged 45-66 years, treated with up to 21 3-month cycles (five years) of sequential oestrogen-progestogen HRT. Treatment consisted of 70 days of 2 mg/day oestradiol valerate (E(2)V), followed by 14 days of E(2)V combined with 20 mg/day medroxyprogesterone acetate (MPA), followed by seven days placebo. Endometrial biopsies were assessed at baseline, at 12 months in women with an endometrial thickness >6 mm and in all participants at 24, 36, 48 and 60 months. Mammography was performed at baseline and at 24-month intervals thereafter. Adverse events were assessed throughout the study. RESULTS: Of 132 women enrolled, 94 completed five years of treatment (540 women years). Endometrial changes (oestrogen effect II) were apparent in most women from 24-60 months (95, 83.3% women at 24 months). One case of simple hyperplasia was found (at 60 months), and none of complex hyperplasia or endometrial cancer. The pattern and frequency of adverse events were consistent with other sequential oestrogen-progestogen HRT regimens. CONCLUSIONS: The incidence of hyperplasia over five years (0.19%, upper 95% CI 0.88) was well within the acceptable rates defined by the European Union Committee for Proprietary Medicinal Products (CPMP).

Epididymal dysfunction initiated by the expression of simian virus 40 T-antigen leads to angulated sperm flagella and infertility in transgenic mice.

We have generated two transgenic mouse lines (GPX5-Tag1 and GPX5-Tag2) by expressing the Simian virus 40 large and small T-antigens under a 5-kb promoter of the murine glutathione peroxidase 5 (GPX5) gene. In GPX5-Tag1 mice, with a high level of T-antigen expression, severe dysplasia was found in the epididymis and seminal vesicles. These mice also developed adrenal and prostate tumors, and spermatogenesis was disrupted. In GPX5-Tag2 mice, with a lower level of T-antigen expression, the only histological change was the slightly hyperplastic epithelium in the initial segment of the epididymidis and in the seminal vesicles. Despite normal mating behavior, these mice were infertile. The most conspicuous feature of the sperm was angulation of the flagellum, which appeared during epididymal transit, probably due to the observed reduction in the osmotic pressure of cauda epididymidal fluid. The angulation did not affect the motility or kinematic parameters of the sperm, but the sperm were also incapable of fertilization in vitro. The lack of expression of several genes specific for the initial segment suggests that in the GPX5-Tag2 mice the transgene expression brings about a differentiation arrest in this part of epididymis. This novel mouse line provides a model for epididymal dysfunction leading to defects in posttesticular sperm maturation and infertility.

No increased risk of endometrial hyperplasia with fixed long-cycle hormone replacement therapy after two years.

The appropriate dose of progestogen during long-cycle hormone replacement is still under debate. We present preliminary two-year results from an open five-year clinical trial of 132 postmenopausal women. All subjects had long-cycle HRT consisting of 70 days 2 mg oestradiol valerate (E(2)V), followed by 14 days 2 mg E(2)V plus 20 mg medroxyprogesterone acetate, and a seven-day hormone-free period. No endometrial samples with hyperplasia or indicative of malignancy were found at 24 months.