Phase II Study of Low Dose and High Dose Conjugated Estrogen for Androgen Independent Prostate Cancer

Pathophysiology, Biomarkers, and Therapeutic Modalities Associated with Skeletal Muscle Loss Following Spinal Cord Injury

A spinal cord injury (SCI) may lead to loss of strength, sensation, locomotion and other body functions distal to the lesion site. Individuals with SCI also develop secondary conditions due to the lack of skeletal muscle activity. As SCI case numbers increase, recent studies have attempted to determine the best options to salvage affected musculature before it is lost. These approaches include pharmacotherapeutic options, immunosuppressants, physical activity or a combination thereof. Associated biomarkers are increasingly used to determine if these treatments aid in the protection and reconstruction of affected musculature.

A phase II randomized clinical trial using aglycone isoflavones to treat patients with localized prostate cancer in the pre-surgical period prior to radical prostatectomy

Prostate cancer (PCa) is the most common cancer in American men. Additionally, African American Men (AAM) are 60% more likely to be diagnosed with PCa and 2.4 times more likely to die from this disease compared to Caucasian men (CM). To date, there are few strategies effective for chemoprevention for men with localized PCa. There is thus a need to continue to evaluate agents and strategies for chemoprevention of prostate cancer. Epidemiological, laboratory and early phase clinical trials have shown that the isoflavones modulates several biomarkers implicated in prostate carcinogenesis. The goal of this phase II randomized clinical trial was to explore the comparative effectiveness and safety of 40 mgs of aglycone isoflavones in AAM and CM with localized PCa in the pre-surgical period prior to radical prostatectomy. Thirty six participants (25 CM, 6AAM) were randomized to the isoflavone arm and 34 (25 CM, 7AAM) to the placebo arm, with 62 completing the intervention. Results indicated that isoflavones at a dose of 20 mgs BID for 3-6 weeks was well tolerated but did not reduce tissue markers of proliferation. A significant reduction in serum PSA was observed with isoflavone supplementation in CM compared to the placebo arm, but not observed in AAM. We observed no changes in serum steroid hormones with isoflavone supplementation. In AAM, a reduction in serum IGF-1 concentrations and IGF1: IGFBP-3 ratios were observed with isoflavone supplementation. Well-powered studies for longer duration of intervention may inform future trials with isoflavones, for chemoprevention of PCa.

Clinical Efficacy of a Novel Therapeutic Principle, Anakoinosis

Classic tumor therapy, consisting of cytotoxic agents and/or targeted therapy, has not overcome therapeutic limitations like poor risk genetic parameters, genetic heterogeneity at different metastatic sites or the problem of undruggable targets. Here we summarize data and trials principally following a completely different treatment concept tackling systems biologic processes: the principle of communicative reprogramming of tumor tissues, i.e., anakoinosis (ancient greek for communication), aims at establishing novel communicative behavior of tumor tissue, the hosting organ and organism via re-modeling gene expression, thus recovering differentiation, and apoptosis competence leading to cancer control - in contrast to an immediate, "poisoning" with maximal tolerable doses of targeted or cytotoxic therapies. Therefore, we introduce the term "Master modulators" for drugs or drug combinations promoting evolutionary processes or regulating homeostatic pathways. These "master modulators" comprise a broad diversity of drugs, characterized by the capacity for reprogramming tumor tissues, i.e., transcriptional modulators, metronomic low-dose chemotherapy, epigenetically modifying agents, protein binding pro-anakoinotic drugs, such as COX-2 inhibitors, IMiDs etc., or for example differentiation inducing therapies. Data on 97 anakoinosis inducing schedules indicate a favorable toxicity profile: The combined administration of master modulators, frequently (with poor or no monoactivity) may even induce continuous complete remission in refractory metastatic neoplasia, irrespectively of the tumor type. That means recessive components of the tumor, successively developing during tumor ontogenesis, are accessible by regulatory active drug combinations in a therapeutically meaningful way. Drug selection is now dependent on situative systems characteristics, to less extent histology dependent. To sum up, anakoinosis represents a new substantive therapy principle besides novel targeted therapies.

Favourable response of serum prostate-specific antigen to conjugated oestrogen in castrate-resistant prostate cancer in Jamaica

Conjugated oestrogen is one of the more affordable secondary hormonal options available for castrate-resistant prostate cancer (CRPC) in Jamaica. The present study was conducted to examine the disease response in Jamaican men with CRPC treated with conjugated oestrogen. This study retrospectively reviewed the medical notes of patients who attended the urologic clinic of the University Hospital of the West Indies from 1 January 2009 to 31 December 2013 and a private urology clinic from 2 November 2005 to 3 June 2015 to identify patients diagnosed with CRPC treated with conjugated oestrogen (Premarin ®) as secondary therapy. The primary endpoint of favourable response, using the Prostate Cancer Clinical Trials Working Group 2 criteria is a decline of ≥50% in serum prostate-specific antigen (PSA) concentrations from baseline after treatment. The proportion of patients responding by the first 3-month follow-up visit and the maximal PSA declined over the 24 months of follow-up which were recorded. Thirty-two patients diagnosed with CRPC and treated with conjugated oestrogen were identified. All patients were prescribed 5.0 mg (2.5 mg tablets, twice daily) orally, as well as low dose aspirin. Favourable response was observed in 14 (43.8%) patients; however, eight other patients showed a decline in serum PSA concentration of <50%. There were no reported adverse effects. Conjugated oestrogen produced a PSA decline in Jamaican CRPC patients of this study and may therefore be a useful option for secondary therapy of CRPC. Further assessment is needed.

Sequencing current therapies in the treatment of metastatic prostate cancer

The standard treatment for metastatic prostate cancer is androgen deprivation therapy. However, progressive, metastatic disease usually develops, giving rise to metastatic castration-resistant prostate cancer (mCRPC). Great improvements have been made recently in the management of mCRPC, with current approved treatments including chemotherapy, androgen receptor-targeted agents, immunotherapies and radiopharmaceuticals. While the emergence of multiple effective therapies is encouraging, devising a treatment strategy can be difficult and it is becoming increasingly important, and challenging, to identify factors that influence the ideal timing of specific therapies. Considering where to place these agents in the treatment schedule of mCRPC, or whether these agents should be sequenced or combined to derive the optimal benefit for the patient, is not yet clear. Furthermore, cross-resistance may exist between these agents, which may ultimately influence treatment decisions and sequence choices. Preliminary data are emerging regarding the safety and activity for sequential treatment regimens, but there are currently no prospective studies. As prostate cancer is highly heterogeneous clinically, it is likely that no single treatment sequence will be optimal for all patients. However, at present, there are no validated biomarkers to guide individualized treatment for mCRPC. Here we review available data for the different mCRPC treatments, discussing potential sequencing of agents and possible cross-resistance or synergy among the recently approved and emerging therapies.

Androgen-deprivation therapy for nonmetastatic prostate cancer is associated with an increased risk of peripheral arterial disease and venous thromboembolism

BACKGROUND

Previous studies demonstrate that androgen-deprivation therapy (ADT) with gonadotropin-releasing hormone (GnRH) agonists and orchiectomy for prostate cancer (PCa) is associated with cardiovascular disease. However, few studies have examined its effect on the peripheral vascular system.

OBJECTIVE

To study the risk of peripheral artery disease (PAD) and venous thromboembolism associated with ADT for PCa.

DESIGN, SETTINGS, AND PARTICIPANTS

This was a population-based observational study of 182 757 US men ≥ 66 yr of age who were diagnosed with nonmetastatic PCa from 1992 to 2007, with a median follow-up of 5.1 yr, of whom 47.8% received GnRH agonists and 2.2% orchiectomy.

MEASUREMENTS

We used Cox proportional hazards models with time-varying treatment variables to adjust for demographic and tumor characteristics in assessing whether treatment with GnRH agonists or orchiectomy were associated with PAD and/or venous thromboembolism.

RESULTS AND LIMITATIONS

GnRH agonist use was associated with an increased risk of incident PAD (adjusted hazard ratio [HR]: 1.16; 95% confidence interval [CI], 1.12-1.21) and incident venous thromboembolism (adjusted HR: 1.10; 95% CI, 1.04-1.15). In addition, orchiectomy was associated with an increased risk of peripheral arterial disease (adjusted HR: 1.13; 95% CI, 1.02-1.26) and venous thromboembolism (adjusted HR: 1.27; 95% CI, 1.11-1.45). Limitations include the observational study design and the inability to assess the use of oral antiandrogens.

CONCLUSIONS

ADT for nonmetastatic PCa is associated with an increased risk of PAD and venous thromboembolism. Additional research is needed to better understand the potential risks and benefits of ADT, so that this treatment can be targeted to patients for whom the benefits are clearest.

Estradiol suppresses tissue androgens and prostate cancer growth in castration resistant prostate cancer

Background

Estrogens suppress tumor growth in prostate cancer which progresses despite anorchid serum androgen levels, termed castration resistant prostate cancers (CRPC), although the mechanisms are unclear. We hypothesize that estrogen inhibits CRPC in anorchid animals by suppressing tumoral androgens, an effect independent of the estrogen receptor.

Methods

The human CRPC xenograft LuCaP 35V was implanted into orchiectomized male SCID mice and established tumors were treated with placebo, 17β-estradiol or 17β-estradiol and estrogen receptor antagonist ICI 182,780. Effects of 17β-estradiol on tumor growth were evaluated and tissue testosterone (T) and dihydrotestosterone (DHT) evaluated by mass spectrometry.

Results

Treatment of LuCaP 35V with 17β-estradiol slowed tumor growth compared to controls (tumor volume at day 21: 785 ± 81 mm³ vs. 1195 ± 84 mm³, p = 0.002). Survival was also significantly improved in animals treated with 17β-estradiol (p = 0.03). The addition of the estrogen receptor antagonist ICI 182,780 did not significantly change survival or growth. 17β-estradiol in the presence and absence of ICI 182,780 suppressed tumor testosterone (T) and dihydrotestosterone (DHT) as assayed by mass spectrometry. Tissue androgens in placebo treated LuCaP 35V xenografts were; T = 0.71 ± 0.28 pg/mg and DHT = 1.73 ± 0.36 pg/mg. In 17β-estradiol treated LuCaP35V xenografts the tissue androgens were, T = 0.20 ± 0.10 pg/mg and DHT = 0.15 ± 0.15 pg/mg, (p < 0.001 vs. controls). Levels of T and DHT in control liver tissue were < 0.2 pg/mg.

Conclusions

CRPC in anorchid animals maintains tumoral androgen levels despite castration. 17β-estradiol significantly suppressed tumor T and DHT and inhibits growth of CRPC in an estrogen receptor independent manner. The ability to manipulate tumoral androgens will be critical in the development and testing of agents targeting CRPC through tissue steroidogenesis.

The mechanism of action of estrogen in castration-resistant prostate cancer: clues from hormone levels

BACKGROUND

Estrogen therapy plays a role in the management of castration-resistant prostate cancer (CRPC), although the mechanism of action is not fully known. This current analysis reports the relationship of change in adrenal androgen levels and prostate-specific antigen (PSA) response in patients with CRPC treated with estrogen therapy.

PATIENTS AND METHODS

Hormone levels were measured for patients with CRPC treated in a multicenter phase II trial of 2 estrogen-containing compounds, the herbal supplement PC-SPES and diethylstilbestrol (DES), with known efficacy in CRPC. Patients with castrate levels of testosterone were randomized to initially receive either PC-SPES 960 mg t.i.d. or DES 3 mg/day. Levels of testosterone, dihydrotestosterone (DHT), estradiol, estrone, sex hormone-binding globulin (SHBG), dehydroepiandrosterone (DHEA), DHEA-sulfate (DHEA-S), and androstenedione were obtained at baseline and at 12-week intervals until disease progression. Hormone levels were obtained for 38 patients, 20 treated with PC-SPES and 18 treated with DES.

RESULTS

Significant declines between baseline and 12 weeks of treatment were observed in levels of serum testosterone (P < .001), estrone (P = .02), and DHEA (P < .001). The percent changes at 12 weeks in these hormone levels were inversely proportional to baseline values as measured by Spearman's rank correlation (testosterone: -0.41, P = .01; estrone: -0.64, P = .0001; DHEA: -0.39, P = .02). Levels of SHBG increased in almost all of the patients (97%), with a median percent increase of > 5-fold (P < .0001). Of the 38 evaluable patients, 15 (39% [95% CI, 24%-57%]) experienced a > 50% decline in PSA level. There was no significant difference between treatment groups or between responders and nonresponders in baseline distributions for any of the hormones. At follow-up, 73% of the responders had a decline in the level of DHEA-S compared with 41% of the nonresponders, resulting in a difference in the distribution of the percent change between the subsets (Mann-Whitney test: P = .03). Conversely, 64% of the responders compared with 30% of the nonresponders experienced an increase in DHT, with differing distributions of percent change (P = .02).

CONCLUSION

Androgens decline in response to estrogen therapy. A decline in DHEA-S and a rise in DHT are both associated with a decline in PSA while patients receive estrogen therapy.

Activity of ketoconazole after taxane-based chemotherapy in castration-resistant prostate cancer

OBJECTIVE

To assess the efficacy of the androgen-synthesis inhibitor ketoconazole as a secondary hormonal therapy in patients with castration-resistant prostate cancer (CRPC) previously treated with chemotherapy, as persistent androgens appear to play a role in the development and maintenance of CRPC.

PATIENTS AND METHODS

We retrospectively identified 34 patients with CRPC who were treated with ketoconazole as a secondary hormonal therapy after paclitaxel- or docetaxel-based chemotherapy for CRPC. They were treated with ketoconazole 200-400 mg three times daily with or without hydrocortisone. Patients with previous use of ketoconazole were excluded. Half the patients had received estramustine as part of their chemotherapy regimen. The primary endpoint was the proportion of patients with a decline of > or =50% in their prostate-specific antigen (PSA) level. PSA progression was defined by the PSA Working Group 1 Criteria.

RESULTS

Eight of the 32 evaluable patients (25%) had a PSA decline of > or =50%. The median time to progression (TTP) was 3 months (95% confidence interval, 1.2-5.4). A history of previous response to taxane-based chemotherapy was not associated with the response to ketoconazole. However, previous use of oestrogens for CRPC was significantly associated with a shorter TTP on ketoconazole (1.5 vs 10.2 months; P = 0.03).

CONCLUSIONS

Ketoconazole has moderate activity as secondary hormonal therapy in patients with CRPC previously treated with taxane-based chemotherapy, although the TTP was short. Previous treatment with oestrogenic therapy is associated with a shorter TTP.

Androgen receptor: role and novel therapeutic prospects in prostate cancer

Androgen receptor (AR) signaling is necessary for the development of prostate cancer. Androgen-deprivation therapy (ADT) for prostate cancer was described over 50 years ago and ADT remains the mainstay of systemic therapy. AR signaling remains intact as the disease evolves to castration-resistant prostate cancer (CRPC). Through cellular adaptations, CRPC continues to rely on androgens and AR growth signaling, and thus AR remains an important therapeutic target. CRPC cells upregulate enzymes used in androgen synthesis, thus providing an intracellular source of androgen despite systemic castration. Compounds in development, such as antiandrogens, lyase inhibitors, heat-shock protein-90 inhibitors, histone deacetylase inhibitors and others, will provide new tools to more effectively reduce ligand, inhibit AR and/or inhibit costimulatory pathways and result in improved clinical outcomes.