Long-term outcome for men with androgen independent prostate cancer treated with ketoconazole and hydrocortisone

The Efficacy of Ketoconazole Containing Regimens in Castration-Resistant Prostate Cancer: A Systematic Review and Meta-Analysis

Castration resistant prostate cancer (CRPC) is a challenging subset of prostate cancer associated with an extensive metastatic profile and high mortality. Ketoconazole is a nonselective steroid 17α-hydroxylase/17,20 lyase (CYP17A1) inhibitor and is employed as a second line treatment option for CRPC with an established efficacy profile in patients. The aim of this study is to assess the efficacy of ketoconazole containing regimens for CRPC in terms of prostate specific antigen (PSA) decline rate using a systematic review and meta-analysis. In this review, an electronic search was carried out on PubMed, Cochrane CENTRAL, Scopus, and Google Scholar to find relevant literature. Random effects model was used to assess pooled PSA decline rate and 95% CIs. Publication bias was assessed using the funnel plot symmetry and one-tailed Egger's and Begg's test. In all cases, P-value <.05 was indicative of significant results. The review is registered with PROSPERO: CRD42023466536. A total of 483 articles were retrieved after database searching, out of which 23 studies (having a total of 1315 patients) were included in the review based on prespecified criteria. The PSA decline rate was reported in the 14 observational studies (having 964 patients) and 9 experimental studies (having 351 patients). Pooled results revealed that 48.6% (95% CI 43.1-54.2; P-value <.001; I2 = 73.24%) of participants achieved more than 50% decline in PSA (602/1315 participants). Sensitivity analysis using the leave-one-out method revealed no substantial change in pooled effect estimates; (Risk Ratio) RR 47.2% to RR 49.8% demonstrating the robustness of our results. There was no evidence of publication bias as assessed from the funnel plot symmetry. Ketoconazole containing regimens have shown moderate efficacy in high risk CRPC patients as demonstrated by the pooled results. Hence, a ketoconazole based chemotherapy can be added to patients' regimen if there is a persistent rise in PSA levels after androgen deprivation therapy.

Repurposing antifungal drugs for cancer therapy

BACKGROUND

Repurposing antifungal drugs in cancer therapy has attracted unprecedented attention in both preclinical and clinical research due to specific advantages, such as safety, high-cost effectiveness and time savings compared with cancer drug discovery. The surprising and encouraging efficacy of antifungal drugs in cancer therapy, mechanistically, is attributed to the overlapping targets or molecular pathways between fungal and cancer pathogenesis. Advancements in omics, informatics and analytical technology have led to the discovery of increasing "off-site" targets from antifungal drugs involved in cancerogenesis, such as smoothened (D477G) inhibition from itraconazole in basal cell carcinoma.

AIM OF REVIEW

This review illustrates several antifungal drugs repurposed for cancer therapy and reveals the underlying mechanism based on their original target and "off-site" target. Furthermore, the challenges and perspectives for the future development and clinical applications of antifungal drugs for cancer therapy are also discussed, providing a refresh understanding of drug repurposing.

KEY SCIENTIFIC CONCEPTS OF REVIEW

This review may provide a basic understanding of repurposed antifungal drugs for clinical cancer management, thereby helping antifungal drugs broaden new indications and promote clinical translation.

Testosterone analysis in prostate cancer patients

Testosterone is an essential steroid hormone associated with a wide variety of biological processes in humans. In prostate cancer, androgen signaling is an important driver of tumor cell growth. Depletion of gonadal testosterone, achieved by surgical or chemical castration, prevents androgenic signaling and temporally reduces, stops or reverses tumor growth before inevitable progression to castration-resistant prostate cancer occurs. Additional treatment strategies targeting androgenic signaling have become available, although these are without curative intent. While circulating testosterone is also associated with disease risk and potential clinical utility, the main use in the clinical lab is monitoring adequate castration and subsequent resistance to therapy. Adequate castrate testosterone concentrations are currently based on over 50 year-old double-isotope derivative assays that are disputed in automated immunoassay (IA) analysis. The debate has been further fueled with the introduction of mass spectrometry-based assays for testosterone, offering a substantial increase in sensitivity and specificity. In this review, we discuss testosterone regulation and androgen deprivation therapy in prostate cancer. We provide an overview of the developments in testosterone analysis for monitoring adequate castration and resistance to therapy. Current clinical practice and future clinical utility will be discussed. Finally, clinical and research recommendations will be presented.

Therapies Targeted to Androgen Receptor Signaling Axis in Prostate Cancer: Progress, Challenges, and Hope

Prostate cancer is the mostly commonly diagnosed non-cutaneous malignancy and the second leading cause of cancer-related death affecting men in the United States. Moreover, it disproportionately affects the men of African origin, who exhibit significantly greater incidence and mortality as compared to the men of European origin. Since androgens play an important role in the growth of normal prostate and prostate tumors, targeting of androgen signaling has remained a mainstay for the treatment of aggressive prostate cancer. Over the years, multiple approaches have been evaluated to effectively target the androgen signaling pathway that include direct targeting of the androgens, androgen receptor (AR), AR co-regulators or other alternate mechanisms that impact the outcome of androgen signaling. Several of these approaches are currently in clinical practice, while some are still pending further development and clinical evaluation. This remarkable progress has resulted from extensive laboratory, pre-clinical and clinical efforts, and mechanistic learnings from the therapeutic success and failures. In this review, we describe the importance of androgen signaling in prostate cancer biology and advances made over the years to effectively target this signaling pathway. We also discuss emerging data on the resistance pathways associated with the failure of various androgen signaling- targeted therapies and potential of this knowledge for translation into future therapies for prostate cancer.

The role of ketoconazole in current prostate cancer care

Ketoconazole is a nonselective steroid 17α-hydroxylase/17,20 lyase (CYP17A1) inhibitor that has been used, off-label, as a second-line therapy for castration-resistant prostate cancer (CRPC). The drug has shown clinical efficacy without survival benefit. Despite not improving survival, ketoconazole has beneficial characteristics, such as its low cost, a relatively favourable toxicity profile compared with chemotherapy, and its efficacy both before and after chemotherapy. The approval of several new, highly effective treatments, including abiraterone acetate, enzalutamide, and apalutamide, warrants re-evaluation of the role of ketoconazole and other classic agents in achieving the optimal timing and sequencing of available agents to prolong survival and maintain patients' quality of life. In the current CRPC treatment landscape, we believe that ketoconazole can be considered in patients with nonmetastatic CRPC and in those with metastatic CRPC who do not respond to, tolerate, or have access to chemotherapy and other standard therapeutic options.

Effects of Ketoconazole on ACTH-Producing and Non-ACTH-Producing Neuroendocrine Tumor Cells

Prolonged remission of hypercortisolism with steroidogenesis inhibitors has been described in patients with ectopic adrenocorticotropic hormone (ACTH) syndrome. The anti-proliferative and pro-apoptotic effect of ketoconazole in human cancer cells was previously suggested. The aim of this study was to explore the effects of ketoconazole on ACTH-producing and non-ACTH-producing neuroendocrine tumor (NET) cell lines. The effects of ketoconazole alone, and in combination with somatostatin analogs, were evaluated in two human cell lines: DMS-79 (ectopic ACTH-producing small cell lung carcinoma) and BON-1 (human pancreatic NET). Total DNA measurement, apoptosis, cell cycle, chromogranin A (CgA)/proopiomelanocortin (POMC) expression by qRT-PCR, serotonin, CgA, and ACTH secretion assays were performed. In both cell lines, ketoconazole significantly suppressed cell growth and colony formation in a dose and time-dependent manner. The effect in DMS-79 was primarily cytotoxic, while it was more apoptotic in BON-1 cells. Ketoconazole also induced increase in G0/G1 phase in both cell lines and arrest in phase G2/M of BON-1 cells. Ketoconazole did not affect the secretion of serotonin, CgA, ACTH, or the mRNA expression of CgA and POMC. Decreased serotonin secretion was observed after the combination treatment with pasireotide. These results suggest a direct effect of ketoconazole on cell proliferation, apoptosis, and cell cycle in both ACTH- and non-ACTH-producing NET cells.

Comparison of abiraterone acetate versus ketoconazole in patients with metastatic castration resistant prostate cancer refractory to docetaxel

BACKGROUND

Abiraterone, a potent CYP 17 inhibitor, is standard treatment in docetaxel refractory, metastatic castrate resistant prostate cancer (mCRPC). However, in countries where abiraterone has not been approved yet, or for patients who cannot afford it, ketoconazole is used as an alternative CYP 17 inhibitor. Although preclinical data suggests that ketoconazole is a less potent inhibitor of CYP 17, there are limited clinical data comparing both agents. We aimed to compare the clinical effectiveness of abiraterone versus ketoconazole in docetaxel refractory mCRPC.

METHODS

Records from mCRPC patients treated with ketoconazole (international multicenter database, n = 162) were reviewed retrospectively. Twenty-six patients treated post docetaxel were individually matched by clinicopathologic factors to patients treated with abiraterone (national multicenter database, n = 140). We compared the PSA response, biochemical and radiological progression free survival (PFS), and overall survival (OS) between the groups. PFS and OS were determined by Cox regression.

RESULTS

The groups were matched by Gleason score, pre-treatment disease extent, ECOG PS, pre-treatment risk category (Keizman, Oncologist 2012). Furthermore, they were balanced regarding other known confounding risk factors. In the groups of abiraterone versus ketoconazole, PSA response was 46% versus 19% (OR 4.3, P = 0.04), median biochemical PFS 7 versus 2 months (HR 1.54, P = 0.02), median radiological PFS 8 versus 2.5 months (HR 1.8, P = 0.043), median OS 19 versus 11 months (HR 0.53, P = 0.79), and treatment interruption d/t severe adverse events 8% (n = 2) versus 31% (n = 8) (0R 0.6, P = 0.023).

CONCLUSIONS

In docetaxel refractory mCRPC, the outcome of abiraterone treatment may be superior to ketoconazole.

Castration-resistant prostate cancer: AUA Guideline

PURPOSE

This Guideline is intended to provide a rational basis for the management of patients with castration-resistant prostate cancer based on currently available published data.

MATERIALS AND METHODS

A systematic review and meta-analysis of the published literature was conducted using controlled vocabulary supplemented with keywords relating to the relevant concepts of prostate cancer and castration resistance. The search strategy was developed and executed by reference librarians and methodologists to create an evidence report limited to English-language, published peer-reviewed literature. This review yielded 303 articles published from 1996 through 2013 that were used to form a majority of the guideline statements. Clinical Principles and Expert Opinions were used for guideline statements lacking sufficient evidence-based data.

RESULTS

Guideline statements were created to inform clinicians on the appropriate use of observation, androgen-deprivation and antiandrogen therapy, androgen synthesis inhibitors, immunotherapy, radionuclide therapy, systemic chemotherapy, palliative care and bone health. These were based on six index patients developed to represent the most common scenarios encountered in clinical practice.

CONCLUSIONS

As a direct result of the significant increase in FDA-approved therapeutic agents for use in patients with metastatic CRPC, clinicians are challenged with a multitude of treatment options and potential sequencing of these agents that, consequently, make clinical decision-making more complex. Given the rapidly evolving nature of this field, this guideline should be used in conjunction with recent systematic literature reviews and an understanding of the individual patient's treatment goals. In all cases, patients' preferences and personal goals should be considered when choosing management strategies.

[Recomendations on the management of controversies in advanced castrate-resistant prostate cancer]

CONTEXT

Controversies and uncertainties among integral management of advanced castration resistant prostate cancer continue to exist despite the number of evidence based clinical practice guidelines published with high international consensus.

OBJECTIVE

To develop a document that reviews the management of controversies in advanced castration resistant prostate cancer, with recommendations from the definition, to the management in hormonal maneuvers, first-line treatment and second-line with new treatments as cabazitaxel or abirarerone and the multidisciplinary approach of the pathology with the goal of finding the most efficient, best time to act and safety.

EVIDENCE ACQUISITION

Two meetings of a multidisciplinary group of experts involved in the management of this disease (Oncologist and Urologist) where pooled analysis of original literature and reached consensus document of recommendations on castration resistant prostate cancer, reviewing and attempting to address the current controversies of the disease.

EVIDENCE SYNTHESIS

This document is endorsed by the corresponding Scientific Associations and Working Groups involved in the current management of Genitourinary Tumours: the Spanish Association of Urology (AEU) with the Uro-Oncoloy Group (GUO) and the Spanish Oncology of Genitourinary Group (SOGUG).

CONCLUSIONS

With the adaptation and implementation of this Document of Recommendations for clinical practice are available for the first time, a real road map for quality, efficiency and safety in the management of patients with CRPC.

Pretreatment neutrophil-to-lymphocyte ratio in metastatic castration-resistant prostate cancer patients treated with ketoconazole: association with outcome and predictive nomogram

BACKGROUND

The neutrophil-to-lymphocyte ratio (NLR), an inflammation marker, is prognostic in several cancers. We assessed the association between the pretreatment NLR and outcome of patients with metastatic castration-resistant prostate cancer (mCRPC) treated with the CYP17 inhibitor ketoconazole.

METHODS

This was an international, retrospective study of 156 mCRPC patients treated with ketoconazole. The independent effect of the pretreatment NLR and factors associated with treatment outcome were determined by multivariate analysis.

RESULTS

Seventy-eight patients (50%) had a ≥50% decline in prostate-specific antigen (PSA). The median progression-free survival (PFS) time was 8 months. Excluded from the analysis were 23 patients without available data on their NLR and those with a recent health event or treatment associated with a blood count change. Sixty-two patients (47%) had a pretreatment NLR >3. Risk factors associated with the PFS outcome were a pretreatment NLR >3 and PSA doubling time (PSADT) <3 months and a prior response to a gonadotropin-releasing hormone agonist of <24 months or to an antiandrogen of <6 months. The number of risk factors was used to form a predictive nomogram by patient categorization into favorable (zero or one factor), intermediate (two factors), and poor (three or four factors) risk groups.

CONCLUSIONS

In mCRPC patients treated with ketoconazole, the pretreatment NLR and PSADT, and prior response to androgen-deprivation therapy, may be associated with the PFS time and used to form a risk stratification predictive nomogram.

Role of hormonal therapy for prostate cancer: perspective from Japanese experiences

Hormonal therapy has been playing an important role in the treatment of prostate cancer. However, it has recently been the subject of criticism that it shows minimal effectiveness, it may reduce patients' quality of life, and induce adverse effects. On the other hand, next-generation hormonal drugs have provided new strategies for hormonal therapy to overcome advanced prostate cancer. Therefore, it is necessary to accumulate further clinical evidence concerning the efficacy and adverse effects of hormonal therapy. And, what is important for the treatment of prostate cancer is how we use hormonal therapy most effectively. This article presents a review of the possible roles of hormonal therapy for prostate cancer based upon experience in Japan.

[Castration-resistant prostate cancer: where are we going?]

CONTEXT

Hormonal therapy allows effective control of cancer-related symptoms in advanced stages. However, the disease will progress in almost all these metastatic prostate cancer patient until becoming resistant to androgen suppression. The emergence of new drugs will most probably have open up new expectations regarding the treatment of this cancer.

OBJECTIVE

The aim of the present review has been to provide an overview of the current status of castration-resistant prostate cancer and to share the high expectations created with the new treatments.

EVIDENCE ACQUISITION

Evidence was obtained from multidisciplinary meetings with the participation of urologists and oncologists, where they pooled the analysis of original articles in the literature and defined the content of the article.

EVIDENCE SYNTHESIS

Chemotherapy with docetaxel was a turning point in castration-resistant prostate cancer after the failure of hormonal therapy failure. For the first time, it achieved increased survival time in comparison with mitoxantrone and prednisone. Combination therapy with docetaxel and prednisone is the first-line choice treatment. Once the cancer has progressed, there is no clear alternative, although some novel agents have created expectations for the treatment of this type of cancer.

CONCLUSIONS

The range of therapeutic options for castration-resistant prostate cancer has increased dramatically with the arrival of new drugs. At present, cabazitaxel, and in the near future, abiraterone, have been found to be effective drugs in second-line treatment after progression to docetaxel, increasing survival by 2-4 months and reducing risk of death by 30-35%.

Contemporary experience with ketoconazole in patients with metastatic castration-resistant prostate cancer: clinical factors associated with PSA response and disease progression

BACKGROUND

Adrenal/intratumoral androgen biosynthesis contributes to ligand-dependent androgen receptor activation in metastatic castration-resistant prostate cancer (mCRCP). Compounds targeting CYP-17 hydroxylase and lyase, as ketoconazole and abiraterone, block adrenal/intratumoral androgen biosynthesis, and are used as sequential endocrine approaches in mCRCP. We aimed to describe contemporary experience and association of clinical factors with Prostate specific antigen (PSA) response and disease progression, in mCRPC progressing on GnRH-agonist, antiandrogen, antiandrogen withdrawal, and treated with ketoconazole.

METHODS

Data were retrospectively analyzed in all mCRPC patients treated with ketoconazole. Patients continued GnRH-agonist, and treated with ketoconazole 200-400 mg 3× a day until dose-limiting toxicity or disease progression. A multivariate cox regression model was used to identify clinical factors associated with PSA response and disease progression.

RESULTS

From 1999 to 2010, 114 mCRPC patients were treated with ketoconazole. With a median follow-up time of 31 months (range 5-129), 25 patients (22%) had grade 3/4 toxicity, most commonly fatigue, abdominal discomfort, nausea, and dizziness. Sixty-one patients (54%) had ≥50% PSA decline. Median time to progression was 8 months (range 1-129). Factors associated with PSA response and disease progression were response to prior antiandrogen (≥6 vs. <6 months), pre-treatment PSADT (≥3 vs. <3 months) and extent of disease (limited-axial skeleton and/or nodal vs. extensive-appendicular skeleton and/or visceral).

CONCLUSIONS

Ketoconazole is effective and safe in mCRPC. Prior response to antiandrogen, pre-treatment PSADT, and disease extent are associated with PSA response and disease progression, and further supports a therapeutic role in suppressing adrenal androgens in mCRPC.

Comparison of Ketoconazole and Estramustine for Treating Patients with Castration-Resistant Prostate Cancer

Purpose

We investigated the efficacy of ketoconazole and estramustine before chemotherapy for treating patients with progressive castration-resistant prostate cancer (CRPC) after anti-androgen withdrawal syndrome.

Materials and Methods

Eighty-four patients who were diagnosed with CRPC and were treated between 2005 and 2009 were included. Thirty-nine patients were treated with 600 mg of ketoconazole and 10 mg of prednisolone per day (group I), and 45 patients were treated with 560 mg of estramustine per day (group II). The prostate-specific antigen (PSA) response, progression-free survival, and side effects were compared.

Results

The median age of the patients, PSA level, and follow-up period were 72 years, 48.5 ng/ml, and 4 months (range, 1 to 29 months), respectively. The overall PSA response rate was 35.7%, and the PSA response rates were 33.3% for group I and 37.8% for group II (p=0.672). The median progression-free survival times were 8 months (95% confidence interval [CI] 5.9-10.1) overall, 5 months (95% CI 1.6-8.3) in group I, and 8 months (95% CI 5.9-10.0) in group II (p=0.282). The most common complications in groups I and II were nausea and vomiting (51.3%) and anemia (77.8%), respectively. Nausea and vomiting and hepatotoxicity were observed more often in group I, and gynecomastia, neutropenia, and anemia were observed more often in group II. The toxicities of each adverse effect were ≤grade 2.

Conclusions

With a resultant PSA decline and mild adverse effects, both ketoconazole and estramustine are worth consideration as treatment options for progressive CRPC patients after primary hormonal therapy.

Low dose of ketoconazole in patients with prostate adenocarcinoma resistant to pharmacological castration

OBJECTIVE

• To assess the efficacy of ketoconazole in patients with castration-resistant prostate cancer (CRPC).

PATIENTS AND METHODS

• From April 2008 to November 2009, 37 patients with CRPC have been treated with ketoconazole. The primary endpoint was the prostate-specific antigen (PSA) response; the secondary endpoints were progression-free survival and safety profile. • Ketoconazole was administered by oral route at a dose of 200 mg every 8 h continuous dosing until the onset of serious adverse events or disease progression. • The study was based on a two-step design with an interim efficacy analysis carried out on the first 12 patients accrued.

RESULTS

• Main characteristics of population were: median age 75 years (range 60-88); baseline mean PSA 28.8 ng/mL (4.3-1000); 30 patients previously challenged with at least two lines of hormone therapy; 15 patients previously treated with chemotherapy. • Biochemical responses accounted for: two complete responses (5%), six partial responses (16%), 13 patients with stable disease (35%), and 14 with progressive disease (38%). Of 15 patients resistant to chemotherapy, overall disease control (complete plus partial responses plus stable disease) was recorded in seven of them. • Treatment was feasible without inducing grade 3-4 adverse events. The most common grade 1-2 adverse events were asthenia (27%), vomiting (8%) and abdominal pain (8%).

CONCLUSION

• Treatment with low-dose ketoconazole is feasible and well tolerated. The efficacy was satisfactory in patients previously treated with chemotherapy.

Itraconazole, a commonly used antifungal that inhibits Hedgehog pathway activity and cancer growth

In a screen of drugs previously tested in humans we identified itraconazole, a systemic antifungal, as a potent antagonist of the Hedgehog (Hh) signaling pathway that acts by a mechanism distinct from its inhibitory effect on fungal sterol biosynthesis. Systemically administered itraconazole, like other Hh pathway antagonists, can suppress Hh pathway activity and the growth of medulloblastoma in a mouse allograft model and does so at serum levels comparable to those in patients undergoing antifungal therapy. Mechanistically, itraconazole appears to act on the essential Hh pathway component Smoothened (SMO) by a mechanism distinct from that of cyclopamine and other known SMO antagonists, and prevents the ciliary accumulation of SMO normally caused by Hh stimulation.

[Management of metastatic androgeno-independent prostate cancer]

After first line hormonal therapy (agonist LHRH), metastasic prostate cancer becomes androgen independent in a period of 18 months on average. After this period and after having verified the castration by blood testosterone level, a few options are possible: either inhibit adrenal androgens by maximum androgen blockage (+anti androgens) or by specific adrenal androgen inhibitors. It is also possible to use estrogen or, in a few cases, to propose chemotherapy.

Phase II study of fulvestrant (Faslodex) in castration resistant prostate cancer

BACKGROUND

Preclinical evidence supports the role of estrogen receptor signaling in prostate cancer. In this trial we investigated the tolerability and efficacy of fulvestrant, a pure estrogen receptor antagonist, in the treatment of castration resistant prostate cancer (CRPC).

METHODS

Patients with CRPC were enrolled after written informed consent. Fulvestrant was administered by intramuscular injection at a dose of 500 mg on day 0, then 250 mg on day 14, day 28 and monthly thereafter. History, physical examination, serum prostate specific antigen (PSA) levels and toxicity was evaluated monthly. Radiographic studies were repeated every 3 months to assess disease. Treatment was continued until disease progression, unacceptable toxicity, non-compliance or consent withdrawal.

RESULTS

Twenty patients were enrolled over a period of six months. All patients were Caucasians with median age of 69.5 years [range: 47-85 years]. Sixteen patients (80%) had radiological evidence of metastasis and four patients (20%) had rising PSA as the only evidence of progressive disease. Patients received a median of three treatment cycles of fulvestrant [range: 1-11]. Median time to progression was 4.3 months (95% confidence interval of 3-5.7 months) and median overall survival was 19.4 months (range: 9.9-19.4 months) after a median follow-up of 16 months. No patient showed >or=50% reduction in PSA or radiologic improvement. Few adverse events were noted, none of which were attributed directly to fulvestrant.

CONCLUSION

Fulvestrant was well tolerated but failed to produce clinical or PSA response in men with CRPC.

Leuprorelin depot injection: patient considerations in the management of prostatic cancer

Hormone therapy is well established for treating patients with prostate cancer and remains the mainstay of the treatment of metastatic and locally advanced disease, this article reviews the rationale for its use, its different forms, and complications and controversies still surrounding some of its modalities. Availability of long-acting synthetic luteinizing hormone-releasing hormone (LHRH) agonists revolutionized the hormonal treatment of prostate cancer, and helped to avoid the emotional and psychological effects related to surgical castration. The depot formula has gained wide acceptance from both patients and physicians. This review emphasizes the newer, long-acting formula, leuprorelin (leuprolide acetate), especially the 6-month formula, its advantage over over shorter-acting depot products, and its potential to become a standard of care for patients eligible for androgen deprivation therapy.

Induction of the NAD(P)H:quinone oxidoreductase 1 by ketoconazole and itraconazole: a mechanism of cancer chemoprotection

Studies in many carcinogen-induced animal models and cell lines demonstrated that azole antifungal drugs are therapeutically effective against different types of cancer. Yet, the molecular mechanisms involved are still poorly understood. Therefore, we examined the ability of three structurally different antifungal drugs, ketoconazole (KTZ), itraconazole (ITZ), and fluconazole (FLZ) to induce the expression of NAD(P)H:quinone oxidoreductase 1 (Nqo1), an enzyme known to play an important role in xenobiotic and carcinogen detoxifications. We showed that KTZ and ITZ, but not FLZ, induced Nqo1 mRNA and enzymatic activity levels in a concentration- and time-dependent manner in wild-type but not aryl hydrocarbon receptor (AhR)-deficient Hepa 1c1c7 cells. Furthermore, KTZ and ITZ increased Nqo1 de novo RNA synthesis without significantly affecting the levels of existing RNA, suggesting a transcriptional mechanism is involved. This study provides the first evidence for the ability of KTZ and ITZ to induce the Nqo1 gene expression through an AhR-dependent mechanism.

Efficacy of Low-dose Ketoconazole in Hormone Refractory Prostate Cancer Patients at the National Cancer Centre and The Cancer Institute, Singapore

Introduction: The advent of prostate specific antigen (PSA) has resulted in an increased incidence of early detection of prostate cancer recurrence. Patients treated with androgen deprivation therapy (ADT) become hormone-resistant after 18 to 24 months. In patients with biochemical failure, where there is a rise in PSA but no objective evidence of metastases, or in whom there are small volume metastases but who are asymptomatic, there is no standard of care after ADT. Ketoconazole, an antimycotic which affects the synthesis of androgens and other steroids, has shown direct cytotoxic effects in prostate cancer cell lines in in-vitro studies. This study describes our experience with ketoconazole treatment for hormone refractory prostate cancer (HRPC). Materials and Methods: A retrospective study of HRPC patients given ketoconazole at the National Cancer Centre and The Cancer Institute from 2004 to 2005 was performed. All eligible patients had histologically proven adenocarcinoma of the prostate and a rising PSA level despite ADT with orchidectomy or luteinising hormone-releasing hormone (LHRH) agonist therapy. All patients received 200 mg of ketoconazole thrice daily. Response was defined as a decline in PSA of at least 50% from the pre-treatment level and confirmed by a second PSA value 4 or more weeks later. The endpoints evaluated were the presence and duration of a response and the toxicity profile of the treatment. Results: A total of 32 patients with HRPC were treated with ketoconazole. Twelve (38%) of the 32 patients had a greater than 50% decrease in their PSA values. The median duration of response was 6.75 months. The median time to reach PSA nadir was 3.5 months. Five patients continue to exhibit progression-free response at the time of writing. Ketoconazole was generally well tolerated. Eighteen (56%) patients recorded mild toxicities related to ketoconazole. There were no grade 3 or 4 toxicities. Key words: Androgen deprivation therapy, Prostate specific antigen

Prostate Cancer-Specific Survival and Clinical Progression-Free Survival in Men with Prostate Cancer Treated Intermittently with Testosterone Inactivating Pharmaceuticals

OBJECTIVES

More than 85% of men with prostate cancer die of other causes. An effective method is needed to distinguish fatal forms of prostate cancer from benign variants.

METHODS

We performed a retrospective chart review from a medical oncology practice specializing in prostate cancer. All men with negative bone scans, prostate-specific antigen (PSA) level less than 100 ng/mL, adequate records for review, and who started taking testosterone inactivating pharmaceutical (TIP) agents before January 2000 were included in the study. Six factors were evaluated as potential predictors of prostate cancer-specific mortality: PSA nadir greater than 0.05 ng/mL while taking TIP, PSA doubling time of less than 12 months, Gleason score, stage, baseline PSA level greater than 20 ng/mL, and age.

RESULTS

The study criteria were met by 160 men. The median follow-up was 10 years. The median age, PSA level, PSA nadir, and PSA doubling time was 65.6 years, 9.6 ng/mL, 0.03 ng/mL, and 10 months, respectively. Of the 160 men, 39 died of prostate cancer. Death from prostate cancer was far more common (78% versus 11%) and accelerated (median of 4 years versus 7 years) for men with a PSA nadir greater than 0.05 ng/mL than for those with a lower nadir. Multivariate Cox regression analysis indicated that the hazard ratio for prostate cancer-specific mortality in men with a PSA nadir greater than 0.05 ng/mL was 11.6 (P <0.0001). The hazard ratio for men with a PSA doubling time of less than 12 months was 2.9 (P = 0.04). Gleason score, stage, baseline PSA level greater than 20 ng/mL, and age were not statistically significant.

CONCLUSIONS

Of the factors studied, the PSA nadir while taking a TIP was the best predictor of prostate cancer-specific mortality.

Significant Prostate-Specific Antigen (PSA) Response to Low-Dose Ketoconazole in a Patient With Non-Metastatic Androgen-Independent Prostate Cancer (AIPC) and a Review of the Literature

Although there are a variety of treatment options for nonmetastatic androgen-independent prostate cancer (AIPC), they have limited benefits. Currently, no standard of care exists for this population. Ultimately, sequential therapeutics can be used to minimize symptomatic progression and control the underlying disease, as determined by prostate-specific antigen (PSA) levels. We report here a 90-year-old patient who had PSA progression after multiple previous treatments and was started on ketoconazole 200 mg, three times daily. His serum PSA levels dropped 84% in less than a year on therapy. A literature review yields several studies that support the benefits of ketoconazole as noted by PSA reduction and correlates these responses with survival benefits. The literature also suggests that low-dose ketoconazole may be an appropriate second- or third-line hormonal agent in AIPC, causing a PSA decline, symptomatic relief, and minimal toxicity.

Recent progress in hormonal therapy for advanced prostate cancer

PURPOSE OF REVIEW

Primary androgen deprivation therapy and secondary hormonal therapy remain the cornerstones of treatment for advanced prostate cancer. This review outlines the basic evidence for use of hormonal therapy while highlighting major research developments made in the past year.

RECENT FINDINGS

Recent research on androgen deprivation therapy has suggested that patients with high-risk features may have longer metastasis-free survival with early initiation of androgen deprivation therapy. Fracture risk has been shown to be significantly increased in patients on androgen deprivation therapy and is correlated with duration of treatment. In the treatment of androgen-independent prostate cancer, oral premarin has been shown to induce of prostate specific antigen responses more than 50% in 32% of patients, though thromboembolism remains a risk despite prophylactic low-dose warfarin. Transdermal estradiol has been associated with virtually no cardiovascular toxicity, but induced of prostate specific antigen responses more than 50% in only 12.5% of patients. Clinical studies of nilutamide, flutamide, and ketoconazole have further clarified efficacy of these secondary hormonal treatments.

SUMMARY

Optimal timing of androgen deprivation therapy awaits the results of randomized trials, but available evidence indicates that patients with high-risk features may benefit from early androgen deprivation therapy. New estrogen-based therapies have shown promising efficacy in the treatment of androgen-independent prostate cancer, with significantly less cardiovascular toxicity than traditional estrogens.

Response to low-dose ketoconazole and subsequent dose escalation to high-dose ketoconazole in patients with androgen-independent prostate cancer

BACKGROUND

High-dose ketoconazole (HDK) in combination with steroids has been recognized as an effective secondary hormonal therapy in androgen-independent prostate cancer (AIPC). However, HDK causes more severe adverse events than low-dose ketoconazole (LDK). To the authors' knowledge, relatively little is known regarding the efficacy of LDK in AIPC. The efficacy of LDK and of subsequent dose escalation from LDK to HDK was evaluated as secondary hormonal therapy in patients with AIPC.

METHODS

In a single institution, patients with AIPC treated with LDK (at a dose of 200 mg orally 3 times daily) as secondary hormonal therapy with or without concomitant steroids were retrospectively identified. In addition, patients were identified who received dose escalation to HDK (400 mg orally 3 times daily) after experiencing a rising prostate-specific antigen (PSA) level.

RESULTS

Thirty-nine of 138 eligible patients (28.3%, 95% confidence interval [95% CI], 20.9-36.6%) treated with LDK experienced PSA declines > or =50%. The median time to disease progression or dose escalation on LDK was 3.2 months (range, 0.1(+)-61 months). Dose escalation to HDK was subsequently performed in 55 patients (39.9%), 7 of whom (12.7%) demonstrated a subsequent PSA decline > or =50%. A longer duration of primary androgen deprivation therapy and total duration of all previous hormonal therapies was associated with a longer time to progression with LDK (P < .05). The most common reversible adverse effect of LDK was NCI Common Toxicity Criteria Grade 1 or 2 fatigue (12.3%).

CONCLUSIONS

LDK is associated with a PSA response rate comparable to HDK as secondary hormonal therapy in patients with AIPC, but with less toxicity. Although uncommon, additional durable responses occurred in some patients after dose escalation.

[Hormone-refractory prostate cancer. Modifications of the therapeutic strategies since chemotherapy proved its usefulness]

Back in the 90's it was difficult to have access to the conclusions of publications on HRPC. Homogeneity was very scarce regarding issues as significant as the definition of HRPC itself, patient selection, or evaluation of the responses to therapy. Consensus has currently been reached on such matters, and it is described in this text. Two works were published in late 2004 showing that docetaxel-based chemotherapy improved metastatic HRPC survival. Until then, the different treatments used could only provide symptomatic relief. But probably not all of the HRPC patients are eligible for primary docetaxel chemotherapy. The current debate focuses on determinating to which patients should chemotherapy be administered and at which time should it start, in order to exclude those patients at risk of experiencing its adverse effects without benefitting from its clinical advantages. Non-metastatic HRPC patients may be candidates to receiving secondary hormone manoeuvres before starting with chemotherapy. We will analyse in this review the changes occurred in the therapeutic strategies ever since chemotherapy showed its value, and we shall also disclose our attitude regarding treatment of these patients in daily practice.

Increased expression of genes converting adrenal androgens to testosterone in androgen-independent prostate cancer

Androgen receptor (AR) plays a central role in prostate cancer, and most patients respond to androgen deprivation therapies, but they invariably relapse with a more aggressive prostate cancer that has been termed hormone refractory or androgen independent. To identify proteins that mediate this tumor progression, gene expression in 33 androgen-independent prostate cancer bone marrow metastases versus 22 laser capture-microdissected primary prostate cancers was compared using Affymetrix oligonucleotide microarrays. Multiple genes associated with aggressive behavior were increased in the androgen-independent metastatic tumors (MMP9, CKS2, LRRC15, WNT5A, EZH2, E2F3, SDC1, SKP2, and BIRC5), whereas a candidate tumor suppressor gene (KLF6) was decreased. Consistent with castrate androgen levels, androgen-regulated genes were reduced 2- to 3-fold in the androgen-independent tumors. Nonetheless, they were still major transcripts in these tumors, indicating that there was partial reactivation of AR transcriptional activity. This was associated with increased expression of AR (5.8-fold) and multiple genes mediating androgen metabolism (HSD3B2, AKR1C3, SRD5A1, AKR1C2, AKR1C1, and UGT2B15). The increase in aldo-keto reductase family 1, member C3 (AKR1C3), the prostatic enzyme that reduces adrenal androstenedione to testosterone, was confirmed by real-time reverse transcription-PCR and immunohistochemistry. These results indicate that enhanced intracellular conversion of adrenal androgens to testosterone and dihydrotestosterone is a mechanism by which prostate cancer cells adapt to androgen deprivation and suggest new therapeutic targets.