Ketoconazole therapy for hormonally refractive metastatic prostate cancer

Novel functionalized 5-(phenoxymethyl)-1,3-dioxane analogs exhibiting cytochrome P450 inhibition: a patent evaluation WO2015048311 (A1)

Cytochrome P450's (CYP's) constitute a diverse group of over 500 monooxygenase hemoproteins, catalyzing transformations that involve xenobiotic metabolism, steroidogenesis and other metabolic processes. Over-production of the steroid hormone cortisol is implicated in the progression of diseases such as diabetes, heart failure and hypertension, stroke, Cushing's syndrome, obesity and renal failure, among others. The biosynthesis of cortisol involves a cascade of cholesterol metabolizing reactions regulated through three major CYP proteins: 17α-hydroxylase-C17/20-lyase (CYP17), 21-hydroxylase (CYP21), and 11β-hydroxylase (CYP11B1). Excess activities of these enzymes are linked to the progression of malignancies including prostate, breast, ovarian, and uterine cancers. A series of novel functionalized dioxane analogs have been developed and recently patented as CYP17, CYP21, and CYP11B1 inhibitors, which lead to the modulation of cortisol production as a method for treating, delaying, slowing, and inhibiting the implicated diseases. The findings disclosed in this patent have been analyzed and compared with the literature data on inhibitors of CYP17, CYP21, and CYP11B1. The compiled data provide insight into the novel functionality of the compounds described in the patent. In this regard, an objective opinion on the effectiveness and novel biochemistry of these compounds in comparison to current CYP inhibitors used in the treatment of cortisol-related diseases is presented in this paper.

Metastatic castrate-resistant prostate cancer: dawn of a new age of management

What's known on the subject? and What does the study add? Metastatic castrate-resistant prostate cancer (mCRPC) was historically considered to be an aggressive disease resistant to conventional anticancer therapy. Within the last decade the outlook has changed beyond recognition; docetaxel chemotherapy is now firmly established as a well-tolerated treatment with significant survival benefits. Building on this, more recently there have been several landmark developments using various approaches in patients whose disease has progressed despite previous chemotherapy. Cabazitaxel chemotherapy offers survival and health-related quality of life (HRQL) improvements in this setting, as does the CYP inhibitor abiraterone acetate. Significant clinical benefits are also seen with novel radioisotope and immunotherapeutic approaches. There have been many developments in the management of this condition within the last 2 years, with several landmark studies showing new treatments that offer survival and HRQL benefits even in the setting of advanced disease, which has been heavily pretreated. This review article summarises these important developments and gives the reader an overview of current practice, recent changes and future directions. With current and forthcoming developments in the treatment of metastatic castrate-resistant prostate cancer (mCRPC) post-docetaxel, we are embarking on an age of potential 'chronic' management of this disease. It is hoped that the survival benefits associated with the various treatments, cytotoxic, hormonal and immunotherapeutic, will prove to be additive, providing a multimodal continuum of care. If so, it will be necessary to determine the optimal sequence and timing of the new treatments. One key factor in this regard is likely to be the patient's performance status and hence his eligibility for cytotoxic intervention. If chemotherapy is offered early in the post-docetaxel pathway, the patient may still be able to benefit from non-chemotherapeutic options subsequently. However, if this stage of management begins with a non-chemotherapeutic option, there is a risk that the patient's performance status will decline before he has an opportunity to benefit from chemotherapy. Further studies and ongoing clinical experience are likely to clarify this important issue, and help clinicians to maximise the survival of men with mCRPC post-docetaxel.

Management of metastatic castration-resistant prostate cancer after first-line docetaxel

Although chemotherapy, based on docetaxel, is now established in the management of metastatic castration-resistant prostate cancer (mCRPC), until recently, there has been no treatment licensed for use in the second line in men whose disease progresses during or after docetaxel therapy. This article reviews the classes of agents that have shown potential in this setting, notably chemotherapy drugs, hormonal therapies, immunotherapies, anti-angiogenic drugs, and clusterin-targeted therapy.

A phase I clinical study of high dose ketoconazole plus weekly docetaxel for metastatic castration resistant prostate cancer

PURPOSE

This phase I study of high dose ketoconazole and docetaxel was designed against castration resistant prostate cancer to determine the maximum tolerated doses, side effects, and pharmacokinetic interaction of co-administered docetaxel and ketoconazole.

MATERIALS AND METHODS

Patients with metastatic castration resistant prostate cancer received weekly docetaxel for 3 of every 4 weeks plus daily ketoconazole. Pharmacokinetic studies were performed on day 1 (docetaxel alone) and day 16 (after ketoconazole).

RESULTS

The study enrolled 42 patients at 9 different dose levels. The combination regimens investigated included docetaxel weekly, increasing from 5 to 43 mg/m(2), with starting doses of 600, 800 or 1,200 mg ketoconazole daily. Decreases in prostate specific antigen of 50% or greater were seen in 62% of patients. Of 25 patients with soft tissue disease 7 (28%) had a partial response. Median overall survival was 22.8 months and was significantly greater in docetaxel naïve patients than in patients pretreated with docetaxel (36.8 vs 10.3 months, p = 0.0001). The most frequently observed adverse events were anemia, edema, fatigue, diarrhea, nausea, sensory neuropathy and elevated liver function tests. The fractional change in docetaxel clearance correlated significantly with ketoconazole exposure (p <0.01). Concomitant ketoconazole increased docetaxel exposure 2.6-fold with 1,200 mg daily, 1.6-fold with 800 mg daily and approximately 1.3 to 1.5-fold with 600 mg daily.

CONCLUSIONS

Combination regimens using 600 mg ketoconazole daily were fairly well tolerated and the maximum tolerated dose of docetaxel was 32 mg/m(2). Results suggest that the combination has significant antitumor activity in castration resistant prostate cancer. The long survival in the docetaxel naïve cohort warrants additional, larger trials of docetaxel with ketoconazole or possibly CYP17A1 inhibitors such as abiraterone.

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

Phase II study of mitoxantrone and ketoconazole for hormone-refractory prostate cancer

BACKGROUND

Doxorubicin plus ketoconazole has exhibited significant activity in patients with advanced prostate cancer. However, overall and cardiac-specific toxicity was reported to be high. Mitoxantrone has activity similar to that of doxorubicin, is less cardiotoxic, and is widely used to treat prostate cancer. The current study sought to evaluate the toxicity and activity of mitoxantrone plus ketoconazole in a cohort of patients with hormone-refractory prostate cancer.

METHODS

Progression after medical or surgical castration and, for those patients receiving antiandrogens, progression after withdrawal was required, as was objective evidence of metastasis, castrate levels of testosterone, an Eastern Cooperative Oncology Group (ECOG) performance status of 0 to 2, and intact cardiac function. After enrollment onto a multicenter local consortium study, subjects were treated with mitoxantrone at a dose of 12 mg/m2 intravenously every 3 weeks plus continuous oral ketoconazole at a dose of 400 mg 3 times daily and ascorbic acid at a dose of 250 mg. Replacement doses of hydrocortisone were given.

RESULTS

For 40 enrolled subjects, the median prostate-specific antigen and ECOG performance status were 68 and 1, respectively, 53% had Gleason scores of 8 to 10, and all had metastasis. Predominant Grade 3/4 toxicities were: neutropenia in 13%, neutropenic fever in 10%, and anemia in 13%. Of 37 evaluable patients, 8% achieved a complete remission (CR) and 62% achieved a partial remission (PR), for a CR plus PR rate of 70%. For soft tissue and bone disease, overall response rates were 13% and 8%, respectively. The median progression-free survival and overall survival were 10 months and 18 months, respectively.

CONCLUSIONS

Mitoxantrone plus ketoconazole is well tolerated, is active in hormone-refractory prostate cancer, and should be studied further.

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

PURPOSE

The combination of high dose ketoconazole and hydrocortisone (HDK) is active against androgen independent prostate cancer (AIPC). Median response times with HDK tend to be brief but a significant minority of AIPC patients benefit with extended responses. Well characterized response and survival information, especially in the cohort of patients who experience these longer, more durable, responses has not been previously reported. Characterization of this subgroup is of particular interest since men with long-term responses derive the greatest benefit from HDK therapy.

MATERIALS AND METHODS

The medical records of 78 patients with AIPC treated with HDK between March 1991 and February 1999 were retrospectively reviewed. Baseline clinical and laboratory factors predictive of prolonged response and survival were identified.

RESULTS

The median baseline prostate specific antigen (PSA) before the initiation of HDK was 25.1. The number of patients with zero, 1 to 3, and more than 3 lesions on bone scan were 25, 35 and 18, respectively. Median and mean time to PSA progression was 6.7 and 14.5 months. Median and mean survival time was 38.0 and 42.4 months, respectively. Response time and survival were highly correlated (r = 0.799). A total of 34 (44%) men had a greater than 75% decrease in PSA. The median survival times in men with more vs less than a 75% decrease were 60 vs 24 months, respectively. In a Cox proportional hazard regression, prolonged survival was predicted by percent PSA decrease, extent of disease on bone scan and baseline PSA.

CONCLUSIONS

Ketoconazole can induce prolonged responses, occasionally lasting for years. Long responses are more likely to occur in men initiating HDK earlier in the course of disease before the cancer burden becomes excessive.

An Evaluation of Intermediate-Dose Ketoconazole in Hormone Refractory Prostate Cancer

OBJECTIVES

The management of hormone refractory prostate cancer remains controversial. Among the options, second-line hormonal therapy is commonly used. We investigated the efficacy of ketoconazole, an inhibitor of testicular and adrenal androgen biosynthesis, for treating patients with advanced hormone refractory prostate cancer.

METHODS

The study comprised 38 patients with progressive disease despite combined androgen blockade. Treatment consisted of intermediate-dose ketoconazole (300mg three times daily) and replacement hydrocortisone. Patients were monitored clinically and with serial psa measurements every 3 months. the principal endpoint was psa response.

RESULTS

Of the 38 patients, 21 (55.3%) showed a decrease in PSA >50% (95% confidence interval 38.3%-71.4%) with a median duration of 6 months (range 3-48 months). A PSA reduction >50% was seen in 21 of 34 patients (61.8%) with established metastases. Thirteen patients (34.2%), all of whom had metastases, exhibited a PSA decrease >80% (95% confidence interval 19.6%-51.4%) with a median duration of 9 months (range 3-48 months). Age, PSA at diagnosis, Gleason score and bone scan result were not significantly associated with response to ketoconazole treatment in univariate or multivariate analyses. For the entire study group, the median time to progression was 5 months (range 0-27 months) and the median survival was 12 months (range 3-48 months). Overall, 12 patients (31.6%) reported toxicity related to intermediate-dose ketoconazole but only 6 patients (15.8%) discontinued therapy due to intolerable side effects.

CONCLUSION

It is apparent from this study that a reasonable percentage of patients failing standard hormonal therapy respond favourably to intermediate-dose ketoconazole and that toxicity is mild. In the absence of studies demonstrating better survival with chemotherapy, we believe that a trial of ketoconazole should be considered when progression occurs on hormone therapy.

Docetaxel and ketoconazole in advanced hormone-refractory prostate carcinoma

BACKGROUND

Docetaxel has significant single-agent activity in patients with prostate carcinoma, and ketoconazole has activity as a second-line hormonal agent. In vitro, ketoconazole exhibits synergy with several chemotherapeutic agents. A potential drug interaction exists, however, because both docetaxel and ketoconazole are metabolized hepatically by the cytochrome p450 system (CYP3A4). The authors performed a Phase I study and a pharmacokinetic study evaluating the both tolerability of a docetaxel/ketoconazole combination as well as this potential drug interaction.

METHODS

For all initial patients, docetaxel was administered intravenously at a dose of 55 mg/m(2) over 1 hour every 21 days. Starting on Day 8 after their first docetaxel dose, cohorts of at least 3-5 new patients were enrolled to receive escalating doses of ketoconazole. When the maximally tolerated dose (MTD) of ketoconazole was reached, the subsequent cohort of patients received an escalating dose of docetaxel. Pharmacokinetic studies were performed after docetaxel infusions on Day 1 (prior to ketoconazole) and Day 22 (after starting ketoconazole).

RESULTS

Twenty-six patients were enrolled and completed at least 2 cycles of treatment. The MTD was ketoconazole 400 mg twice daily and docetaxel 55 mg/m(2). Dose-limiting toxicities included neutropenia and fatigue. Ketoconazole did not cause a consistent effect on docetaxel pharmacokinetics, although there was significant intrapatient and interpatient variability in serum levels.

CONCLUSIONS

The recommended Phase II dose for this combination is ketoconazole 400 mg twice daily and docetaxel 55 mg/m(2) every 21 days.

Hormone-refractory Prostate Cancer

For more than five decades, the preferred treatment for advanced prostate cancer has been suppression of androgen production by medical or surgical castration. However, all patients treated with androgen deprivation eventually develop resistant disease as manifested by increasing prostate-specific antigen levels, progressive disease on imaging studies, and ultimately worsening symptoms. The treatment of patients with hormone-refractory prostate cancer (HRPC), once thought to represent a relatively futile endeavor, has changed significantly in the past several years with the development of new therapeutics. One of the most important new treatment strategies involves secondary hormonal manipulation after the failure of primary androgen deprivation; this approach is predicated on the recognition that HRPC is a heterogenous disease. Some patients may respond to alternative hormonal interventions despite the presence of castrate levels of testosterone. Furthermore, the application of chemotherapeutic regimens has provided viable treatment options for patients with HRPC.

Hormonal treatment for prostate cancer

For nearly six decades the preferred primary treatment for advanced prostate cancer has been continuous suppression of testicular androgen production by medical or surgical castration. While androgen deprivation is effective in inducing tumour regression in the large majority of cases, essentially all patients will develop progressive disease. In addition androgen deprivation may be associated with a variety of side effects. Thus, strategies that minimise the use of these agents could potentially lower the morbidity and cost associated with the treatment of advanced prostate cancer. In the era of prostate-specific antigen (PSA) testing, hormonal therapy is being used earlier in the course of the disease when the only evidence of recurrent disease is an elevated PSA. These men may survive for many years and thus have the potential for long periods of exposure to hormonal therapy and its side effects. It has been hoped that the development of alternative hormonal interventions might lead to both enhanced antitumour efficacy as well as improvements in side effect profile.

Secondary hormonal manipulations in hormone refractory prostate cancer

Hormone refractory prostate cancer is clinically heterogeneous, and many patients retain sensitivity to subsequent hormonal manipulations, even after combined androgen blockage. Antiandrogen withdrawal is a mandatory first step. Subsequent treatment with an alternate antiandrogen, adrenal androgen inhibitor (such as ketoconazole), or glucocorticoid may provide both subjective and objective clinical benefit in up to 65% of patients.

Ketoconazole-induced apoptosis through P53-dependent pathway in human colorectal and hepatocellular carcinoma cell lines

In this study, we first demonstrated that the widely used oral antifungal drug, ketoconazole (KT), can induce apoptosis in various type of human cancer cells and in a primary culture of rat liver cells. We further investigated the molecular mechanisms of KT-induced apoptosis. It was found that KT induced nuclear accumulation of p53 protein in a dose- and time-dependent manner. The level of p53 protein was elevated approximately three times as much in treated cells 24 h after KT (5 microM) exposure as in cells receiving mock treatment. We found that cells containing wild-type p53 (COLO 205 and Hep G2) were more sensitive to KT exposure. The bax protein was induced and the bcl-2 protein was inhibited by KT in cells containing wild-type p53 (Hep G2, COLO 205) but not in cells without p53 (Hep 3B). The caspase-3 was activated 24 h after KT treatment. The Poly-(ADP ribose) polymerase (PARP) and the lamin A degradation was induced by KT, which promoted nuclear membrane disassembly and eventually caused apoptosis. Our results also indicated that none of the PKC gene family was involved in KT-induced apoptosis.

Ketoconazole-induced adrenal crisis in a patient with metastatic prostatic adenocarcinoma: case report and review of the literature

Ketoconazole has been used with success to treat disseminated intravascular coagulation and acute spinal cord compression syndromes associated with metastatic prostatic adenocarcinoma. It effects prompt, reversible medical castration, making it especially useful as empiric therapy when histologic diagnosis is delayed but prostate cancer is suspected. Side effects are usually limited to asthenia, nausea, diarrhea, and gynecomastia, but a theoretical risk of adrenal suppression exists. We report a case of fulminant adrenal crisis precipitated by ketoconazole given on a 6-hour dosing schedule in a patient with nerve root compression secondary to prostatic metastases. Through a review of the literature, we attempt to provide a better understanding of the use and potential dangers associated with ketoconazole therapy.

In vitro effect of gallium nitrate when combined with ketoconazole in the prostate cancer cell line PC-3

Secondary hormonal manipulations are common following the failure of combined androgen blockade in patients with metastatic prostate cancer. Ketoconazole has been shown to have activity in this disease by inhibiting cytochrome P450 steroid hormone biosynthesis, thus inducing androgen deprivation. Gallium nitrate has been reported to target tumor tissue in vitro and some preliminary data suggests activity in patients with prostate cancer. Thus, we conducted a Phase II study of gallium nitrate in patients with androgen-independent prostate cancer. Two patients with progressive prostate cancer were removed from this study and subsequently placed on ketoconazole, as a palliative agent. Surprisingly, both of these patients had a greater than 50% decline in their prostate specific antigen (PSA) with this secondary endocrine maneuver. Based on this clinical observation, we conducted the following in vitro study to determine if there was a substantial additive effect of gallium nitrate followed by ketoconazole. Gallium nitrate or ketoconazole was added to the androgen-independent prostatic epithelial cell line, PC-3. One hundred and twenty hours (120 h) following the addition of one of the agents, the media was aspirated and the second agent was added to the wells. One plate was assayed every 24 h for cell viability using a non-isotopic cell proliferation assay kit. Cells treated with gallium nitrate followed by ketoconazole were 70-100% of control at the end of the gallium nitrate treatment; ketoconazole was then added and viability either remained constant or dropped steadily. Gallium nitrate by itself had a weak inhibitory effect on cell viability that only became apparent at the highest concentration evaluated. Ketoconazole, on the other hand, showed a substantial growth inhibition that was concentration-dependent. Cells treated with this agent alone showed a pronounced steady decrease in viability. Exposure to ketoconazole for 120 h followed by incubation in culture medium alone for 120 h caused a decrease in cell viability to 26.0% of control. Our in vitro results suggest that the combination of gallium nitrate and ketoconazole has no additive activity in the PC-3 cell line. Furthermore, this study confirms that ketoconazole added to prostate cancer cells has antiproliferative activity. The in vitro activity of ketoconazole has traditionally been thought to result from its inhibition of cytochrome P450-dependent enzymes responsible for steroidogenesis; however, an alternative hypothesis is necessary to explain the cytotoxic effect in the absence of adrenal and testicular androgen production as found in an in vitro system.

Hormone refractory disease

Hormone refractory disease is observed in less than 20% of newly diagnosed cases of advanced prostatic cancer. In the majority of cases, hormone refractory disease appears after a median time of 18 months of endocrine manipulation and is attributed to the selection and/or cloning of pre-existing or de novo appearing hormone-independent or resistant cell lines. There are no generally accepted rules for second-line management. The varying sets of criteria used by different study groups make comparisons of widely different regimens very difficult. Actually, it seems reasonable to consider length of survival as the only objective response criterion. This implies, however, that there should be an unanimous definition about the moment of primary treatment failure. Indeed, the detection of hormonal escape is a gradual event and the relative length of survival time depends on the chosen moment of therapy administration. To date, monitoring of prostate specific antigen (PSA) has become the best and primary tool to document progression of disease. Earlier diagnosis based on a rise in PSA levels in patients that are still asymptomatic with a good performance status, might provide the opportunity to treat patients that could profit from therapy and give a fair chance to the investigated drug to show efficacity and tolerability. In this paper we will discuss the rationale of the current available second-line therapeutic options in relapsed prostatic cancer.

Endocrine therapy of advanced carcinoma of the prostate

Increasing evidence suggests that growth of the prostatic tissue is regulated by a network of hormones and growth factors, in which androgens play the prominent role. Hormonal manipulation remains the core of treatment for locally advanced and metastatic prostate cancer. Achievement of a complete androgen blockade, by surgical or medical means or a combination of both, offers superior results in palliative management of advanced disease. Management of hormonal refractory cancer, however, remains a challenge to clinicians.

Ketoconazole and liarozole in the treatment of advanced prostatic cancer

BACKGROUND

Ketoconazole, an imidazole derivative, is an orally active antifungal agent. In high doses (400 mg three times a day), it inhibits the biosynthesis of testicular and adrenal androgens and may therefore be useful for the treatment of hormone dependent diseases such as advanced prostatic cancer. Similarly, a new imidazole derivative, liarozole, was recently found to interfere with testicular and adrenal steroid biosynthesis in animals and healthy volunteers.

METHODS

The therapeutic and endocrine effects of ketoconazole and liarozole in patients with disseminated prostatic cancer are discussed, including data from the literature and personal experience.

RESULTS

Using high-dose ketoconazole, medical castration with the expected clinical response was achieved easily in previously untreated patients in all clinical series (personal data include seven patients). In patients with prostatic cancer who had relapses after castration, few objective remissions were achieved. By contrast, long-lasting subjective remissions, especially pain relief, were seen in more than half of the patients (personal data include 20 patients). Gastrointestinal intolerance, which was the main side effect, severely limits the routine use of the drug. Recently, the authors studied the effect of liarozole on adrenal steroid production in castrated patients whose disease was progressive after first-line treatment. Unlike ketoconazole therapy, adrenal androgen and cortisol levels were not modified. A Phase I-II trial was then done in 44 patients with metastatic prostatic cancer in clinical relapse. In patients with measurable disease, objective responses, including tumoral volume reduction, occurred in approximatively 30%. A prostate specific antigen reduction of 50% or more was noted in approximatively 50% of patients. Pain relief occurred in most patients. Mucocutaneous side effects were observed in most patients--dryness of the skin and onychomalacia. Raised tissue retinoic acid levels suggested a possible pathway by which this drug might exert its cytotoxic effects.

CONCLUSIONS

Ketoconazole in high doses is effective in first-line and second-line therapy for advanced prostatic cancer, but gastrointestinal side effects limit its routine use. Liarozole is a new imidazole that is also effective in second-line therapy for prostatic cancer and has fewer side effects. Unlike ketoconazole, its effect is not mediated by inhibition of steroid biosynthesis.

Hormone treatments in the common 'hormone-dependent' carcinomas

Current understanding of the mechanisms of action of hormonal therapies in carcinomas of the breast, prostate, endometrium and ovary is briefly reviewed. The range of available hormonal therapies for each disease is considered together with response rates, toxicity and any evidence for survival benefit. Practical guidelines for the palliative use of hormonal therapies are suggested.

Management of relapsing disease in prostate cancer

Almost all patients with prostatic cancer will eventually escape the control of the first-line endocrine therapy and relapse. This escape is attributed to selecting and/or cloning preexisting or de novo appearing hormone-independent or resistant cell lines and occurs in most patients after a median time of 12 to 18 months. Currently, there are no generally accepted rules for second-line management, either endocrine or by other means. It seems reasonable to consider length of survival as the only objective response criterion and not to rely on other response criteria. Available second-line therapeutic modalities in relapsed prostatic cancer are alternative endocrine manipulations, chemotherapy, combined endocrine and cytotoxic therapy, new drugs, radiation therapy, and general antitumoral and supportive care. Second-line therapy in relapsed disease makes sense if life can be prolonged while relieving symptoms and maintaining or improving the quality of survival. The capacity to prolong survival is limited. As a result, second-line therapy should aim more at improving the quality rather than the length of survival while considering the specific expectations and wishes of the patient.

Indications for use of ketoconazole in management of metastatic prostate cancer

Newer methods of androgen ablation for the treatment of metastatic prostatic carcinoma have been developed as alternatives to the standard forms of therapy, oral estrogens and surgical castration. The purpose of this review is to elucidate the indications and to determine the role of ketoconazole in the management of metastatic prostatic cancer. Eighteen patients have been treated with ketoconazole. The indications for usage have included: prompt therapeutic response, when orchiectomy is contraindicated, when estrogens are contraindicated, initial empirical therapy, and hormonally refractory disease. It can also be used in conjunction with luteinizing hormone-releasing hormone analogues. Ketoconazole is excellent for short-term usage prior to bilateral orchiectomy and when prompt therapeutic response is needed but orchiectomy cannot be performed. However, it is not particularly useful for long-term hormonal therapy.

Carcinoma of the prostate. Treating disease that has metastasized

Common manifestations of metastatic carcinoma of the prostate are bone pain, spinal cord compression, and disseminated intravascular coagulation. Prostate-specific antigen represents a useful marker to monitor tumor progression and response to therapy. Until recently, no therapy was available to prolong survival in these patients. Now, the use of a luteinizing hormone-releasing hormone agonist (leuprolide acetate [Lupron]) plus an antiandrogen (flutamide [Eulexin]) to provide total androgen blockade has demonstrated a 25% increase in survival time.

Antitumoral effects of R 75251 on the growth of transplantable R3327 prostatic adenocarcinoma in rats

The antitumoral activity of a novel imidazole derivative, R 75,251, has been studied in the androgen-dependent R3327G Dunning prostate adenocarcinoma grafted subcutaneously in syngeneic rats. Dietary application resulting approximately in dose levels of 80, 120, and 160 mg/kg reduced tumor weight by 66, 81, and 79%, respectively. This effect was not significantly different from that measured after castration (-82%). In intact animals, however, serum testosterone levels were almost not affected by R 75,251 treatment while LH levels rose two- to threefold. In castrated rats a tenfold increase in LH was observed. Moreover, prostate and seminal vesicles weights decreased much less after R 75,251 treatment than after castration. In castrated animals, treatment with R 75,251 induced a slight, non-significant reduction in tumor weight (-36%) compared with castration alone. In castrated animals, tumor growth was restored by exogenous administration of testosterone. In such animals R 75,251 also significantly reduced tumor weight by 57%. Similar results were obtained with Dunning R3327G prostate adenocarcinoma grafted beneath the renal capsule in male syngeneic rats receiving twice daily orally by gavage a dose of 80 mg/kg of R 75,251. These data suggest that R 75,251 exerts an antitumoral effect independent of its inhibition of androgen biosynthesis.

R 75251, a new inhibitor of steroid biosynthesis

R 75251, a new imidazole derivative, inhibited the conversion of androgens to estrogens, of progestins to androstenedione and testosterone, and of 11-deoxycorticosterone to corticosterone in human placenta microsomes, subcellular fraction of rat testis, bovine adrenocortical mitochondria, in cultured rat granulosa, testicular and adrenal cells, respectively. In vitro, no effect on cholesterol synthesis and cholesterol side-chain cleavage was found at concentrations up to 10 microM. In rat granulosa cells, no effect on progesterone production was detected. In vitro, no effect on steroid radioligand binding was observed. In male volunteers, a single dose of 300 mg of R 75251 significantly lowered plasma testosterone and estradiol for 24 hours and increased plasma concentration of 17 alpha-hydroxyprogesterone and progesterone. As compared with ketoconazole high dose (600 mg b.i.d), R 75251 (300 mg b.i.d) was at least as efficacious as inhibitor of testosterone synthesis when studied during ACTH stimulation. In contrast to ketoconazole, R 75251 did not significantly affect circulating adrenal androgen levels in male volunteers. Precursors of gluco- and mineralocorticoids such as 11-deoxycortisol and 11-deoxycorticosterone accumulated more than after ketoconazole administration. The data show that the cytochrome P450-dependent aromatase, 17-hydroxylase/17,20-lyase, and 11-hydroxylase are the target enzymes for R 75251.

Hormonal therapy for prostate cancer

Since the demonstration in 1941 by Huggins and Hodges that prostatic cancers are androgen dependent, hormonal treatment by androgen ablation has been the principal treatment for patients with advanced adenocarcinoma of the prostate. Although not able to permanently and totally eradicate every cancer cell since prostate cancer cells are quite heterogeneous in their sensitivity to androgens, hormonal therapy can produce dramatic subjective improvement as well as objective remissions. This results in an improved quality of survival and for patients with metastatic adenocarcinoma, endocrine therapy does reduce the death rate from cancer, and if death from other concurrent illness is controlled, there is an absolute increase in survival. At present, a variety of strategies are available for ablation of testicular and adrenal androgens, but results are not clinically significantly better than orchiectomy.

High dose ketoconazole for the treatment of hormone refractory metastatic prostate carcinoma: 16 cases and review of the literature

We treated 16 patients who had hormone refractory metastatic prostate cancer with 400 mg. ketoconazole orally every 8 hours. None of the patients had an objective response, although 6 (37.5 per cent) had stable disease (2 of whom had a subjective decrease in bone pain). The median duration of stable disease was 6.8 months (range 2 to 12 months) and side effects were seen in 14 patients. Nausea, vomiting or anorexia was noted in 10 patients, rash and pruritus in 2, transient abnormal liver function tests in 1 and transient pulmonary infiltrates in 1. Nine prior studies investigating the use of ketoconazole in hormone refractory metastatic prostate cancer were reviewed. Only 1 complete response was reported. A partial response was noted in 14 per cent of the patients. Most of the patients had stable or progressive disease. High dose ketoconazole as a single agent appears to have limited use in patients who have failed prior systemic therapy.