National Cancer Institute intramural approach to advanced prostate cancer

Prostate cancer treatment and survival: evidence for men with prevalent comorbid conditions

BACKGROUND

The absence of evidence-based guidelines for prostate cancer treatment led the Institute of Medicine to include localized prostate cancer treatment among the 25 most important topics for comparative effectiveness research.

OBJECTIVE

This study compared prostate cancer treatment and survival in men with and without prevalent comorbid conditions.

RESEARCH DESIGN

The sample comprised elderly men, aged 66 years and older, extracted from SEER-Medicare data, between 2004 and 2009 (N=73,563). Treatment and survival for men with at least 1 of 4 prevalent comorbid conditions were compared with men who did not have any of the 12 Charlson comorbid conditions. The sample was stratified by comorbid condition and low-risk, intermediate-risk, and high-risk disease.

RESULTS

Over half of men received some form of cancer-directed treatment, irrespective of comorbid condition. Men who have congestive heart failure (CHF) or multiple comorbid conditions were less likely to be treated, whereas men with diabetes were more likely to be treated. With the exception of men with CHF, men with comorbid conditions and low-risk disease received no survival benefit from any type of treatment.

CONCLUSIONS

Most men received treatment, particularly radiation therapy, regardless of comorbid condition. The evidence suggests more caution should be used when treating men with low-risk disease and comorbid conditions as they are at risk for adverse events and additional medical costs, without a survival benefit.

Employing the treatment-free interval of intermittent androgen ablation to screen candidate prostate cancer therapies

BACKGROUND

Because neither continuous nor intermittent hormonal therapy is curative, we designed a clinical model to screen new drugs for additive or synergistic effects with hormonal therapy and used IM862, a naturally occurring dipeptide with antiangiogenic and immunomodulatory properties, to test it.

METHODS

Patients with prostate cancer who had rising PSA levels after radical prostatectomy and/or radiation therapy were given combined androgen ablation for 3 months. After 2 months' treatment, patients were randomly assigned in a double-blind fashion to receive intranasal IM862 or placebo daily. Treatment continued for 6 months or until disease progression, which was defined by a rising serum PSA level, the appearance of new skeletal or extraskeletal metastatic disease, or new symptoms requiring intervention.

RESULTS

Seventy-one patients were evaluable for response. Median time to PSA progression was not reached in either group. At 6 months, disease had progressed in 14 (41%) of the 34 patients receiving treatment and 18 (49%) of the 37 receiving placebo (P = 0.39). No significant toxicities emerged.

CONCLUSIONS

The model was demonstrated to be an efficient platform for new drug screening; however, IM862, though well tolerated, failed to demonstrate superiority over placebo in prolonging time to PSA progression.

Simultaneous determination of docetaxel and ketoconazole in rat plasma by liquid chromatography/electrospray ionization tandem mass spectrometry

A rapid and sensitive liquid chromatography/tandem mass spectrometry (LC/MS/MS) method has been developed and validated for simultaneous quantification of docetaxel and ketoconazole in rat plasma with paclitaxel as internal standard (IS). The analytes were extracted from rat plasma by using a liquid-liquid extraction technique with ethyl acetate and the LC separation was performed on a Cosmosil-C(18) analytical column (150 mm x 2.0 mm i.d., Nacalai Tesque Inc., Japan). The extracted samples were analyzed with LC/MS/MS, operating in selected reaction monitoring (SRM) mode. The SRM transitions of precursor ions to product ions were 830.3-->549.1 (m/z) for docetaxel, 531.2-->489.3 (m/z) for ketoconazole, and 876.7-->307.9 (m/z) for the IS. The calibration curves were linear over the range of 2-500 ng/mL for docetaxel and 50-20 000 ng/mL for ketoconazole, with coefficients of correlation above 0.999. The limits of quantification for docetaxel and ketoconazole were both 2 ng/mL. The limit of detection for each analyte was 1 ng/mL. The intra- and inter-day precision (CV) of analysis were within 7%, and the accuracy ranged from 95 to 110%. The overall recoveries for docetaxel and ketoconazole were about 89.0% and 91.1%, respectively. The total analysis time was only 9.0 min. This quantitation method was successfully applied to the simultaneous determination of docetaxel and ketoconazole in rat plasma and some potential interaction was found in the current coadministration pharmacokinetic study. This established method was also utilized in the in vitro and in vivo drug-drug interaction study of docetaxel and ketoconazole (to be published).

Intermittent androgen deprivation: clinical experience and practical applications

Prostate cancer is more frequently being diagnosed at an earlier age, men are dying of prostate cancer at an older age, and men are now treated with androgen deprivation for biochemical relapse. As a result, the amount of time that patients are potentially subjected to androgen deprivation is increasing. Intermittent androgen deprivation (IAD) has been investigated as a potential alternative to continuous androgen deprivation (CAD) in order to improve quality of life and potentially delay the progression to androgen independence. Along with the increased use of primary hormonal therapy in clinically localized prostate cancer, IAD may supplant the traditional surgical or radiotherapy options, specifically in men who have underlying co-morbidities and decreased life expectancy. There are ongoing multi-institutional, randomized trials that will lend insight into the utility, efficacy, and feasibility of IAD versus CAD. This article discusses the theoretical benefits and rationale of IAD and reviews the completed and on-going IAD trials. Finally, the controversies, practical applications, and future directions of IAD are addressed.

U94 alters FN1 and ANGPTL4 gene expression and inhibits tumorigenesis of prostate cancer cell line PC3

Background

Insensitivity of advanced-stage prostate cancer to androgen ablation therapy is a serious problem in clinical practice because it is associated with aggressive progression and poor prognosis. Targeted therapeutic drug discovery efforts are thwarted by lack of adequate knowledge of gene(s) associated with prostate tumorigenesis. Therefore there is the need for studies to provide leads to targeted intervention measures. Here we propose that stable expression of U94, a tumor suppressor gene encoded by human herpesvirus 6A (HHV-6A), could alter gene expression and thereby inhibit the tumorigenicity of PC3 cell line. Microarray gene expression profiling on U94 recombinant PC3 cell line could reveal genes that would elucidate prostate cancer biology, and hopefully identify potential therapeutic targets.

Results

We have shown that stable expression of U94 gene in PC3 cell line inhibited its focus formation in culture, and tumorigenesis in nude mice. Moreover gene expression profiling revealed dramatic upregulation of FN 1 (fibronectin, 91 ± 16-fold), and profound downregulation of ANGPTL 4 (angiopoietin-like-4, 20 ± 4-fold) in U94 recombinant PC3 cell line. Quantitative real-time polymerase chain reaction (QRT-PCR) analysis showed that the pattern of expression of FN 1 and ANGPTL 4 mRNA were consistent with the microarray data. Based on previous reports, the findings in this study implicate upregulation of FN 1 and downregulation of ANGPTL 4 in the anti tumor activity of U94. Genes with cancer inhibitory activities that were also upregulated include SERPINE 2 (serine/cysteine protease inhibitor 2, 7 ± 1-fold increase) and ADAMTS 1 (a disintegrin-like and metalloprotease with thrombospondin type 1 motif, 7 ± 2-fold increase). Additionally, SPUVE 23 (serine protease 23) that is pro-tumorigenic was significantly downregulated (10 ± 1-fold).

Conclusion

The dramatic upregulation of FN 1 and downregulation of ANGPTL 4 genes in PC3 cell line stably expressing U94 implicate up-regulation of FN 1 and downregulation of ANGPTL 4 in anti tumor activity of U94. Further studies are necessary to determine functional roles of differentially expressed genes in U94 recombinant PC3 cell line, and hopefully provide leads to potential therapeutic targets in prostate cancer.

Angiogenesis and prostate cancer: Important laboratory and clinical findings

Prostate cancer is the leading cause of cancer diagnosis in men and the second leading cause of cancer-related death. Androgen ablation is effective initially, and progression of disease often occurs in many patients. Although recent reports have noted a survival benefit when patients with androgen-independent prostate cancer are treated with docetaxel, patients still have disease progression. Angiogenesis plays a pivotal role for the growth, invasion, and metastasis of prostate cancer. Therefore, antiangiogenesis is a promising new therapeutic modality. More than 20 antiangiogenic agents are now in various stages of clinical trials. We discuss current knowledge on controlling tumor angiogenesis and advances in the development of antiangiogenic agents with promising antitumor activity in prostate cancer.

Thalidomide and analogues: current proposed mechanisms and therapeutic usage

Microvessel density is a prognostic factor for many cancers, including prostate. For this reason, several studies and therapeutic approaches that target the tumor microvasculature have been attempted. Thalidomide has long been recognized as an antiangiogenic molecule. Recently, this drug has regained favor as an anticancer agent and is in clinical trial for multiple myeloma and prostate cancer, among others. This article will briefly review the proposed mechanisms of action for thalidomide, discuss why these activities are of therapeutic value in diseases currently undergoing clinical trials, and summarize the current status of clinical trials for prostate cancer. The focus will be predominantly on the relationship of thalidomide to angiogenesis, as well as on the future and potential value of thalidomide-inspired structural derivatives.