The rates of septicemia in older adults with prostate cancer treated with abiraterone or enzalutamide: A population-based study

INTRODUCTION

Prostate cancer (PCa) is the most common non-cutaneous tumor among American men. Androgen receptor signaling inhibitors such as abiraterone and enzalutamide have been approved for similar disease states among patients with advanced PCa. Existing data suggest using steroids is associated with an increased risk of infection. Because abiraterone is usually prescribed with prednisone, we sought to compare the risk of septicemia in patients using abiraterone vs. enzalutamide.

MATERIALS AND METHODS

We utilized the SEER-Medicare-linked data and used negative binomial regression models to compare the changes in the rates of septicemia-related hospitalizations six months pre- and post-abiraterone and enzalutamide initiation.

RESULTS

We found that the incidence of septicemia-related hospitalizations increased 2.77 fold within six months of initiating abiraterone (incidence rate ratio [IRR]: 2.77, 95% confidence interval [CI]: 2.17-3.53) 1.97 fold within six months of starting enzalutamide (IRR: 1.97, 95% CI: 1.43-2.72). However, the difference in the changes did not reach statistical significance (interaction IRR: 0.71, 95% CI: 0.48-1.06).

DISCUSSION

The findings suggest that both abiraterone and enzalutamide are associated with an increased risk of septicemia-related hospitalizations. However, the difference in the increase of septicemia risk following the two treatments did not reach statistical significance. Further studies are warranted to understand the mechanisms at play.

Prognostic and predictive analyses of circulating plasma biomarkers in men with metastatic castration resistant prostate cancer treated with docetaxel/prednisone with or without bevacizumab

BACKGROUND

CALGB 90401 (Alliance) was a phase III trial of 1050 patients with metastatic castration-resistant prostate cancer (mCRPC) comparing docetaxel, prednisone, bevacizumab (DP+B) versus DP alone. While this trial did not show an improvement in overall survival (OS), there were improved intermediate outcomes suggesting that subsets of men may derive benefit from this combination. The purpose of this analysis was to identify prognostic and predictive biomarkers associated with OS and progression-free survival (PFS) benefit from DP+B.

METHODS

Baseline EDTA plasma samples from 650 consenting patients were analyzed for 24 biomarkers. The proportional hazards model was utilized to test for the prognostic and predictive importance of the biomarkers for OS. The statistically significant biomarkers of OS were further investigated for prognostic and predictive importance for other secondary outcomes.

RESULTS

15 markers [ICAM-1, VEGF-R3, TIMP-1, TSP-2, Ang-2, Her-3, Osteopontin (OPN), PlGF, VCAM-1, HGF, VEGF, Chromogranin A, IL-6, VEGF-R1, BMP-9] were prognostic of OS, while 9 markers (ICAM-1, VEGF-R3, Her-3, TIMP-1, Ang-2, OPN, PlGF, HGF, and VEGF) were also prognostic of PFS. All markers were statistically significant in univariate analyses after adjustment for multiplicity (FDR < 0.1). In multivariable analyses of OS adjusting for risk score, seven markers had FDR < 0.1, including ICAM-1, VEGF-R3, TIMP-1, Ang-2, VEGF, TSP-2 and HGF. In unadjusted analysis, OPN was predictive of PFS improvement with DP+B, in both univariate and multivariable analysis. However, none of the biomarkers tested were predictive of clinical outcomes after adjusting for multiple comparisons.

CONCLUSIONS

Multiple biomarkers were identified in CALGB 90401 as prognostic of clinical outcomes but not predictive of OS. While OPN may have promise as a potential biomarker for anti-angiogenic therapies, further mechanistic and clinical studies are needed to determine the underlying biology and potential clinical application.

Predictors of consenting to participate in a clinical trial among urban cancer patients

BACKGROUND

Patient participation in clinical trials is influenced by demographic and other individual level characteristics. However, there is less research on the role of geography and neighborhood-level factors on clinical trial participation. This study identifies the demographic, clinical, geographic, and neighborhood predictors of consenting to a clinical trial among cancer patients at a large, urban, NCI-designated cancer center in the Mid-Atlantic region.

METHODS

We used demographic and clinical data from patients diagnosed with cancer between 2015 and 2017. We geocoded patient addresses and calculated driving distance to the cancer center. Additionally, we linked patient data to neighborhood-level educational attainment, social capital and cancer prevalence. Finally, we used generalized linear mixed-effects conditional logistic regression to identify individual and neighborhood-level predictors of consenting to a clinical trial.

RESULTS

Patients with higher odds of consenting to trials were: Non-Hispanic White, aged 50-69, diagnosed with breast, GI, head/neck, hematologic, or certain solid tumor cancers, those with cancers at regional stage, never/former tobacco users, and those with the highest neighborhood social capital index. Patients who lived further from the cancer center had higher odds of consenting to a trial. With every 1-km increase in residential distance, there was a 4% increase in the odds that patients would consent to a trial. Neither of the additional neighborhood-level variables predicted consenting to a clinical trial.

CONCLUSIONS

This study identifies important demographic, patient-level, and geographic factors associated with consenting to cancer clinical trials, and lays the groundwork for future research exploring the role of neighborhood-level factors in clinical trial participation.

Abstract 780: Racial disparities in death from cardiovascular disease for patients with prostate cancer: A population-based study

Introduction: Prostate cancer (PCa) is the most common cancer diagnosis among men in the United States. However, a vast majority of patients with PCa die of causes other than PCa, the most common being cardiovascular disease (CVD). We hypothesize that CVD-related mortality in PCa patients is disproportionately higher among Blacks as compared to Whites.

Methods: We identified patients with PCa from the Surveillance, Epidemiology and End Results (SEER)-Medicare linked files between 1/1/2004 and 12/31/2015. The PCa risk groups were created based on the National Comprehensive Cancer Network criteria: low, intermediate, and high risk. The primary endpoint was CVD-related mortality. The following CVD conditions were included in the CVD-specific mortality: acute myocardial infarction, stroke, congestive heart failure, atrial fibrillation, and ischemic heart disease. A proportional hazards model that considered the competing risks was fitted to address the hypothesis. The model was adjusted for age, year of diagnosis, marital status, income level, SEER-region, state buy-in, radiation, surgery, and education level.

Results: We identified 394,323 patients with PCa. Among these 80% were Whites, 15% were Blacks, and 5% were other races. The median age at diagnosis for Whites, Blacks, and other races was 69, 66, and 70 years, respectively. The incidence of CVD-related mortality was 5.6%, 6.6%, and 5% among Whites, Blacks, and Other races, respectively. Compared to Whites, Blacks had a significantly higher risk of mortality due to CVD across all PCa risk groups (Table). Similar results were not seen when the Other races was compared to Whites.

Conclusion: Blacks with PCa have a significantly higher risk of mortality due to CVD as compared to Whites across all PCa risk groups. Our study highlights the importance of cardio-oncology in the setting of PCa. Further studies are warranted to confirm the findings.

Table: Risk of CVD-related mortality among PCa patients; stratified by PCa risk group.Low-Risk (N=84,367)Intermediate-Risk(N=146,411)High-Risk(N=96,502)HR (95%CI); p-valueHR (95%CI); p-valueHR (95%CI); p-valueWhites(N=316,803)RefRefRefBlacks(N=58,046)1.23 (1.09-1.39); p&lt;0.0011.24 (1.14-1.34); p&lt;0.0011.09 (1.01-1.20); p=0.029Other Races(N=19,474)0.79 (0.60-1.04); p=0.0890.87 (0.74-1.03); p=0.1120.79 (0.69-0.91); p&lt;0.001

Citation Format: Nikita Nikita, Joshua Banks, Scott Keith, Kosj Yamoah, Ulhas P. Naik, Felix J. Kim, David M. Shipon, Wm Kevin Kelly, Timothy R. Rebbeck, Grace Lu Yao. Racial disparities in death from cardiovascular disease for patients with prostate cancer: A population-based study [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 780.

New and topics: enfortumab vedotin mechanisms of response and resistance in urothelial cancer - What do we understand so far?

Enfortumab vedotin (EV) was FDA approved in December 2019 for platinum- and checkpoint-refractory urothelial cancer based on an exceptional 44% response rate, and is currently approved for use after platinum and checkpoint inhibitor therapy. Enfortumab is an antibody-drug conjugate that targets Nectin-4, which is widely expressed in urothelial cancer. Despite this ample target, clinical benefit is not achieved by all patients, and mechanisms of treatment resistance are undescribed. Herein we summarize what is known to date regarding coorelative findings and subgroup analysis and EV response, including novel biopsy data in patients with tumor progression post EV.

A Randomized Phase II Study of Androgen Deprivation Therapy with or without Palbociclib in RB-positive Metastatic Hormone-Sensitive Prostate Cancer

PURPOSE

Palbociclib, a cyclin-dependent kinase (CDK) 4/6 inhibitor, blocks proliferation in a RB and cyclin D-dependent manner in preclinical prostate cancer models. We hypothesized that cotargeting androgen receptor and cell cycle with palbociclib would improve outcomes in patients with metastatic hormone-sensitive prostate cancer (mHSPC).

PATIENTS AND METHODS

A total of 60 patients with RB-intact mHSPC were randomized (1:2) to Arm 1: androgen deprivation (AD) or Arm 2: AD + palbociclib. Primary endpoint was PSA response rate (RR) after 28 weeks of therapy. Secondary endpoints included safety, PSA, and clinical progression-free survival (PFS), as well as PSA and radiographic RR. Tumors underwent exome sequencing when available. Circulating tumor cells (CTC) were enumerated at various timepoints.

RESULTS

A total of 72 patients with mHSPC underwent metastatic disease biopsy and 64 had adequate tissue for RB assessment. A total of 62 of 64 (97%) retained RB expression. A total of 60 patients initiated therapy (Arm 1: 20; Arm 2: 40). Neutropenia was the most common grade 3/4 adverse event in Arm 2. Eighty percent of patients (Arm 1: 16/20, Arm 2: 32/40; P = 0.87) met primary PSA endpoint ≤4 ng/mL at 28 weeks. PSA undetectable rate at 28 weeks was 50% and 43% in Arms 1 and 2, respectively (P = 0.5). Radiographic RR was 89% in both arms. Twelve-month biochemical PFS was 69% and 74% in Arms 1 and 2, respectively (P = 0.72). TP53 and PIK3 pathway mutations, 8q gains, and pretreatment CTCs were associated with reduced PSA PFS.

CONCLUSIONS

Palbociclib did not impact outcome in RB-intact mHSPC. Pretreatment CTC, TP53 and PIK3 pathway mutations, and 8q gain were associated with poor outcome.

Urine Extracellular Vesicle GATA2 mRNA Discriminates Biopsy Result in Men with Suspicion of Prostate Cancer

PURPOSE

Prostate specific antigen has limited performance in detecting prostate cancer. The transcription factor GATA2 is expressed in aggressive prostate cancer. We analyzed the predictive value of urine extracellular vesicle GATA2 mRNA alone and in combination with a multigene panel to improve detection of prostate cancer and high risk disease.

MATERIALS AND METHODS

GATA2 mRNA was analyzed in matched extracellular vesicles isolated from urines before and after prostatectomy (16) and paired urine and tissue prostatectomy samples (19). Extracellular vesicle GATA2 mRNA performance to distinguish prostate cancer and high grade disease was tested in training (52) and validation (165) cohorts. The predictive value of a multigene score including GATA2, PCA3 and TMPRSS2-ERG (GAPT-E) was tested in both cohorts.

RESULTS

Confirming its prostate origin, urine extracellular vesicle GATA2 mRNA levels decreased significantly after prostatectomy and correlated with prostate cancer tissue GATA2 mRNA levels. In the training and validation cohort GATA2 discriminated prostate cancer (AUC 0.74 and 0.66) and high grade disease (AUC 0.78 and 0.65), respectively. Notably, the GAPT-E score improved discrimination of prostate cancer (AUC 0.84 and 0.72) and high grade cancer (AUC 0.85 and 0.71) in both cohorts when compared with each biomarker alone and PT-E (PCA3 and TMPRSS2-ERG). A GAPT-E score for high grade prostate cancer would avoid 92.1% of unnecessary prostate biopsies, compared to 61.9% when a PT-E score is used.

CONCLUSIONS

Urine extracellular vesicle GATA2 mRNA analysis improves the detection of high risk prostate cancer and may reduce the number of unnecessary biopsies.

Clinical outcomes in men of diverse ethnic backgrounds with metastatic castration-resistant prostate cancer

BACKGROUND

We have shown previously in multivariable analysis that black men had 19% lower risk of death than white men with metastatic castration-resistant prostate cancer (mCRPC) treated with a docetaxel and prednisone (DP)-based regimen. The primary goal of this analysis was to compare progression-free survival (PFS), biochemical PFS, ≥50% decline in prostate-specific antigen (PSA) from baseline and objective response rate (ORR) in white, black and Asian men with mCRPC treated with a DP-based regimen.

PATIENTS AND METHODS

Individual patient data from 8820 mCRPC men randomized on nine phase III trials to a DP-containing regimen were combined. Race used in the analysis was based on self-report. End points were PFS, biochemical PSA, ≥50% decline in PSA from baseline and ORR. The proportional hazards and the logistic regression models were employed to assess the prognostic importance of race in predicting outcomes adjusting for established prognostic factors.

RESULTS

Of 8820 patients, 7528 (85%) were white, 500 (6%) were black, 424 were Asian (5%) and 368 (4%) had race unspecified. Median PFS were 8.3 [95% confidence interval (CI) 8.2-8.5], 8.2 (95% CI 7.4-8.8) and 8.3 (95% CI 7.6-8.8) months in white, black and Asian men, respectively. Median PSA PFS were 9.9 (95% CI 9.7-10.4), 8.5 (95% CI 8.0-10.3) and 11.1 (95% CI 9.9-12.5) months in white, black and Asian men, respectively.

CONCLUSIONS

We observed no differences in clinical outcomes by race and ethnic groups in men with mCRPC enrolled on these phase III clinical trials with DP.

PARP-1 regulates DNA repair factor availability

PARP-1 holds major functions on chromatin, DNA damage repair and transcriptional regulation, both of which are relevant in the context of cancer. Here, unbiased transcriptional profiling revealed the downstream transcriptional profile of PARP-1 enzymatic activity. Further investigation of the PARP-1-regulated transcriptome and secondary strategies for assessing PARP-1 activity in patient tissues revealed that PARP-1 activity was unexpectedly enriched as a function of disease progression and was associated with poor outcome independent of DNA double-strand breaks, suggesting that enhanced PARP-1 activity may promote aggressive phenotypes. Mechanistic investigation revealed that active PARP-1 served to enhance E2F1 transcription factor activity, and specifically promoted E2F1-mediated induction of DNA repair factors involved in homologous recombination (HR). Conversely, PARP-1 inhibition reduced HR factor availability and thus acted to induce or enhance "BRCA-ness". These observations bring new understanding of PARP-1 function in cancer and have significant ramifications on predicting PARP-1 inhibitor function in the clinical setting.

MAPK Reliance via Acquired CDK4/6 Inhibitor Resistance in Cancer

Purpose: Loss of cell-cycle control is a hallmark of cancer, which can be targeted with agents, including cyclin-dependent kinase-4/6 (CDK4/6) kinase inhibitors that impinge upon the G1-S cell-cycle checkpoint via maintaining activity of the retinoblastoma tumor suppressor (RB). This class of drugs is under clinical investigation for various solid tumor types and has recently been FDA-approved for treatment of breast cancer. However, development of therapeutic resistance is not uncommon.Experimental Design: In this study, palbociclib (a CDK4/6 inhibitor) resistance was established in models of early stage, RB-positive cancer.Results: This study demonstrates that acquired palbociclib resistance renders cancer cells broadly resistant to CDK4/6 inhibitors. Acquired resistance was associated with aggressive in vitro and in vivo phenotypes, including proliferation, migration, and invasion. Integration of RNA sequencing analysis and phosphoproteomics profiling revealed rewiring of the kinome, with a strong enrichment for enhanced MAPK signaling across all resistance models, which resulted in aggressive in vitro and in vivo phenotypes and prometastatic signaling. However, CDK4/6 inhibitor-resistant models were sensitized to MEK inhibitors, revealing reliance on active MAPK signaling to promote tumor cell growth and invasion.Conclusions: In sum, these studies identify MAPK reliance in acquired CDK4/6 inhibitor resistance that promotes aggressive disease, while nominating MEK inhibition as putative novel therapeutic strategy to treat or prevent CDK4/6 inhibitor resistance in cancer. Clin Cancer Res; 24(17); 4201-14. ©2018 AACR.

Trial Design and Objectives for Castration-Resistant Prostate Cancer: Updated Recommendations From the Prostate Cancer Clinical Trials Working Group 3

PURPOSE

Evolving treatments, disease phenotypes, and biology, together with a changing drug development environment, have created the need to revise castration-resistant prostate cancer (CRPC) clinical trial recommendations to succeed those from prior Prostate Cancer Clinical Trials Working Groups.

METHODS

An international expert committee of prostate cancer clinical investigators (the Prostate Cancer Clinical Trials Working Group 3 [PCWG3]) was reconvened and expanded and met in 2012-2015 to formulate updated criteria on the basis of emerging trial data and validation studies of the Prostate Cancer Clinical Trials Working Group 2 recommendations.

RESULTS

PCWG3 recommends that baseline patient assessment include tumor histology, detailed records of prior systemic treatments and responses, and a detailed reporting of disease subtypes based on an anatomic pattern of metastatic spread. New recommendations for trial outcome measures include the time to event end point of symptomatic skeletal events, as well as time to first metastasis and time to progression for trials in the nonmetastatic CRPC state. PCWG3 introduces the concept of no longer clinically benefiting to underscore the distinction between first evidence of progression and the clinical need to terminate or change treatment, and the importance of documenting progression in existing lesions as distinct from the development of new lesions. Serial biologic profiling using tumor samples from biopsies, blood-based diagnostics, and/or imaging is also recommended to gain insight into mechanisms of resistance and to identify predictive biomarkers of sensitivity for use in prospective trials.

CONCLUSION

PCWG3 moves drug development closer to unmet needs in clinical practice by focusing on disease manifestations most likely to affect prognosis adversely for therapeutics tested in both nonmetastatic and metastatic CRPC populations. Consultation with regulatory authorities is recommended if a trial is intended to seek support for drug approval.

A randomised non-comparative phase II trial of cixutumumab (IMC-A12) or ramucirumab (IMC-1121B) plus mitoxantrone and prednisone in men with metastatic docetaxel-pretreated castration-resistant prostate cancer

BACKGROUND

Cixutumumab, a human monoclonal antibody (HuMAb), targets the insulin-like growth factor receptor. Ramucirumab is a recombinant HuMAb that binds to vascular endothelial growth factor receptor-2. A non-comparative randomised phase II study evaluated cixutumumab or ramucirumab plus mitoxantrone and prednisone (MP) in metastatic castration-resistant prostate cancer (mCRPC).

PATIENTS AND METHODS

Men with progressive mCRPC during or after docetaxel therapy received mitoxantrone 12 mg/m(2) on day 1 and prednisone 5mg twice daily and were randomised 1:1 to receive either cixutumumab or ramucirumab 6 mg/kg intravenously weekly in a 21-day cycle. Primary end-point was composite progression-free survival (cPFS). Secondary end-points included safety, response, radiographic progression-free survival (PFS) and overall survival (OS). Sample size was based on a 50% increase in median cPFS from 2.6 (MP) to 3.9 months (either combination).

RESULTS

132 men were treated (66 per arm). Median cPFS was 4.1 months (95% confidence interval (CI), 2.2-5.6) for cixutumumab and 6.7 months (95% CI, 4.5-8.3) for ramucirumab. Median time to radiographic progression was 7.5 months for cixutumumab and 10.2 months for ramucirumab, with a median OS of 10.8 and 13.0 months, respectively. Fatigue was the most frequent adverse event (AE). Incidence of most non-haematologic grade 3-4 AEs was <10% on both arms. Grade 3 cardiac dysfunction occurred in 7.6% of patients on ramucirumab.

CONCLUSION

Combinations of cixutumumab or ramucirumab plus MP were feasible and associated with moderate toxicities in docetaxel-pretreated men with mCRPC. Of the two regimens, the ramucirumab regimen is worthy of further testing based on the observed cPFS relative to the historical control.

Practical guide to the use of enzalutamide

INTRODUCTION

We summarize the development, definitive trials, and practical use of enzalutamide for practicing urologists and medical oncologists. The care paradigm for patients with metastatic castration resistant prostate cancer (mCRPC) is a changing landscape, with the ongoing discovery of drivers of cancer progression yielding actionable targets for drug development. Since 2010, sipuleucel-T, cabazitaxel, abiraterone with prednisone, radium 223 and enzalutamide have been Food and Drug Administration approved based upon improvement in overall survival in men with mCRPC.

MATERIALS AND METHODS

A MEDLINE search for "enzalutamide or MDV3100" yielded 258 results. Prospective trials were reviewed. Abstracts from ASCO (American Society of Clinical Oncology) meetings and press release information were included where applicable.

RESULTS

Enzalutamide, an oral inhibitor of the androgen receptor pathway, was approved in 2012 based upon improvement in overall survival of 4.8 months in men with mCRPC following docetaxel versus placebo. Measures of prostate-specific antigen (PSA) and radiographic response, and clinically significant endpoints such as quality of life improvement and toxicity parameters favored enzalutamide. Toxicity is modest with asthenia and fatigue being most common, with a 1% incidence of seizure reported, though patients can be selected to decrease this risk.

CONCLUSION

Enzalutamide is an effective oral therapy for mCRPC, with an overall survival benefit before and following chemotherapy. Toxicity is mild, and seizure risk can be mitigated by careful patient selection. Ongoing studies will help determine the best sequence of novel agents for prostate cancer, along with safe and effective combinations of therapies. Better understanding of tumor characteristics, particularly reliance on the androgen receptor pathway, will lead to personalized approaches to prostate cancer therapy.

Targeting epigenetics for the treatment of prostate cancer: recent progress and future directions

Epigenetic aberrations contribute to prostate cancer carcinogenesis and disease progression. Efforts have been made to target DNA methyltransferase and histone deacetylases (HDACs) in prostate cancer and other solid tumors but have not had the success that was seen in the hematologic malignancies. Oral, less toxic, and more specific agents are being developed in solid tumors including prostate cancer. Combinations of epigenetic agents alone or with a targeted agent such as androgen receptor signaling inhibitors are promising approaches and will be discussed further.

Enzalutamide: a novel antiandrogen for patients with castrate-resistant prostate cancer

Enzalutamide (MDV3100, Xtandi, Medivation\Astellas) is an oral inhibitor of androgen receptor signaling that blocks androgen receptor interaction, inhibits translocation of the androgen receptor to the nucleus, impairs androgen receptor binding to DNA, and inhibits coactivator recruitment and receptor-mediated DNA transcription. In a phase III randomized study comparing enzalutamide with placebo in men with progressive castration-resistant prostate cancer (CRPC) who were previously treated with docetaxel, enzalutamide showed an improvement in overall survival (18.4 vs. 13.6 months, HR, 0.63; P < 0.001). In addition, all secondary endpoints including proportion of patients with prostate-specific antigen (PSA) decline, soft-tissue response, quality-of-life response, time to PSA progression, radiographic progression-free survival, and the time to the first radiographic skeletal event all significantly favored patients treated with enzalutamide. Fatigue, diarrhea, and hot flashes were common in patients treated with enzalutamide, with seizures reported in 5 (0.6%) of the patients. Enzalutamide is a novel therapy that very potently blocks the androgen signaling pathway, which is unregulated during the development of CRPC. The preclinical studies along with the pivotal trials that led to its approval by the U.S. Food and Drug Administration (FDA) in September 2012 will be reviewed.

c-Met is a prognostic marker and potential therapeutic target in clear cell renal cell carcinoma

BACKGROUND

Activation of the c-Met pathway occurs in a range of malignancies, including papillary renal cell carcinoma (RCC). Its activity in clear cell RCC is less clear. We investigated c-Met expression and inhibition in a large cohort of RCC tumors and cell lines.

METHODS

c-Met protein expression was determined by automated quantitative analysis (AQUA) on a tissue microarray (TMA) constructed from 330 RCC tumors paired with adjacent normal renal tissue. c-Met expression and selective inhibition with SU11274 and ARQ 197 were studied in clear cell RCC cell lines.

RESULTS

Higher c-Met expression was detected in all RCC subtypes than in the adjacent normal renal tissue (P < 0.0001). Expression was highest in papillary and sarcomatoid subtypes, and high-grade and stage tumors. Higher c-Met expression correlated with worse disease-specific survival [risk ratio = 1.36; 95% confidence interval (CI) 1.08-1.74; P = 0.0091] and was an independent predictor of survival, maintained in clear cell subset analyses. c-Met protein was activated in all cell lines, and proliferation (and colony formation) was blocked by SU11274 and ARQ 197.

CONCLUSIONS

c-Met is associated with poor pathologic features and prognosis in RCC. c-Met inhibition demonstrates in vitro activity against clear cell RCC. Further study of ARQ 197 with appropriate biomarker studies in RCC is warranted.

Screening for prostate cancer: the current evidence and guidelines controversy

INTRODUCTION

Prostate cancer presents a global public health dilemma. While screening with prostate specific antigen (PSA) has led to more men diagnosed with prostate cancer than in previous years, the potential for negative effects from over-diagnosis and treatment cannot be ignored.

MATERIALS AND METHODS

We reviewed Medline for recent articles that discuss clinical trials, evidence based recommendations and guidelines from major medical organizations in the United States and worldwide concerning prostate cancer screening.

RESULTS

Results from the European Randomized Screening for Prostate Cancer (ERSPC), the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial, and Göteborg Swedish trials regarding prostate screening are controversial with the ERSPC and Göteborg showing a reduction in prostate cancer mortality and the PLCO trial showing no benefit. Recommendations from the American Urological Association (AUA), Japanese Urological Association (JUA), and National Comprehensive Cancer Network (NCCN) have recommended that all men obtain a baseline PSA beginning at age 40. The American Cancer Society (ACS) stratifies screening recommendations based on age and risk, but states that screening should take place only after an informed discussion between provider and patient. The United States Preventative Health Service Task Force (USPSTF) states that evidence is insufficient to assess the risks and benefits of prostate cancer screening in men younger than 75 years. Other major international health organizations offer a similar reserved approach or recommend against screening for prostate cancer. Most groups indicate that screening to determine who should undergo prostate biopsy typically includes both a serum PSA and digital rectal examination, with the latest ACS publications noting that the rectal exam is optional. A common theme from all groups is that an informed discussion with the patients is strongly recommended and that screening does increase the number of men diagnosed with non-metastatic, early disease.

CONCLUSIONS

Prostate cancer screening guidelines vary widely between countries and between different medical organizations within individual countries including the United States. Further, the evidence for and against prostate cancer screening remains highly controversial. Longitudinal follow up of completed screening trials is ongoing and may yield additional findings as the time course of prostate cancer outcomes can be protracted. The literature controversy suggests that no standard of care exists for prostate cancer screening today. Until there is agreement in guidelines between major professional organizations who have weighed in on this topic, patients and physicians should be encouraged to consider engaging in shared and informed decision process concerning screening for prostate cancer.

Prostate cancer, comorbidity, and participation in randomized controlled trials of therapy

BACKGROUND

Randomized controlled trials (RCTs) evaluate the potential benefits of chemotherapy regimens and guide clinical care for patients with cancer. Inclusion criteria for RCTs are usually stringent and may exclude many patients seen in clinical practice. Our objective was to determine the proportion of men with castrate-resistant prostate cancer (CRPC) in a clinical setting that would have been excluded from major phase 3 RCTs.

METHODS

We reviewed eligibility criteria from 24 phase 3 clinical trials evaluating chemotherapy for CRPC active from January, 2004, through April, 2008. We created a common list of criteria used in at least 3 studies and separately considered the criteria from a prominent RCT (TAX 327). We applied these criteria to a population of patients with CRPC treated during 2004 to 2006 at the Veterans Affairs Connecticut Healthcare System.

RESULTS

Among 106 patients with CRPC, 99 (93%) had complete medical records, and 45 (45%) of the 99 would have been excluded from RCTs. Common reasons for exclusion were abnormal laboratory values, other malignancies, and other serious medical conditions including cardiac disease.

CONCLUSIONS

Almost half of the CRPC patients examined in a clinical setting would have been ineligible for phase 3 RCTs, highlighting that such trials may not be applicable to general oncology practice.

Efficacy of carboplatin-taxane combinations in the management of castration-resistant prostate cancer: a pooled analysis of seven prospective clinical trials

BACKGROUND

Docetaxel is associated with prolonged survival in castration-resistant prostate cancer (CRPC). Platinum compounds have modest but distinct single-agent activity. Carboplatin may have greatest potential for benefit when combined with taxanes. We investigated whether there is a subset of patients with CRPC for whom the efficacy of combination taxane-estramustine-carboplatin (TEC) chemotherapy may be greatest.

PATIENTS AND METHODS

Individual patient data (n = 310) were obtained from seven trials using TEC chemotherapy. Prostate-specific antigen (PSA) response was defined as > or = 50% post-therapy decline from baseline. Overall survival was defined from baseline to death from any cause. Logistic and Cox regression were used to investigate heterogeneity in outcome to TEC by patient and disease characteristics. Predicted survival probabilities were calculated from the Halabi Cancer and Leukemia Group B (CALGB) nomogram.

RESULTS

The pooled PSA response proportion was 69% [95% confidence interval (CI) 56% to 80%]. There was no evidence of differential PSA response by disease characteristics. Established prognostic factors were associated with survival. The pooled 12-month survival estimate of 79% (95% CI 71% to 84%) was higher than the median 59% 12-month nomogram-predicted survival.

CONCLUSIONS

TEC chemotherapy has significant clinical activity in CRPC. A randomized, controlled trial evaluating the addition of carboplatin to taxane-based chemotherapy is needed to elucidate the value of carboplatin in CRPC.

Histone deacetylase inhibitors: biology and mechanism of action

Histone deacetylases (HDACs) and histone acetyltransferases are enzymes that regulate chromatin structure and function through the removal and addition, respectively, of the acetyl group from the lysine residues of core nucleosomal histones. This posttranslational modification of histones is an important process in the regulation of gene expression. Aberrant expression and recruitment and disrupted activities of HDACs and histone acetyltransferases have been found in malignant tissues, implicating their involvement in cancer. HDAC inhibitors (HDACIs) function through diverse mechanisms, including the promotion of cell cycle arrest and apoptosis and the inhibition of angiogenesis. Malignant cells appear more sensitive to the proapoptotic effects of HDACIs, underscoring the therapeutic potential of these agents. Multiple HDACIs are currently under investigation in clinical trials, including vorinostat (suberoylanilide hydroxamic acid), which was recently approved by the U.S. Food and Drug Administration for the treatment of cutaneous manifestations of cutaneous T-cell lymphoma in patients with progressive, persistent, or recurrent disease on or after 2 systemic therapies.

Pharmacokinetics and toxicity of weekly docetaxel in older patients

PURPOSE

To evaluate the pharmacokinetics of weekly docetaxel in a cohort of older patients with metastatic cancer and to explore the relationship of pharmacokinetic variables, Erythromycin Breath Test results, age, geriatric assessment variables, and toxicity to therapy.

EXPERIMENTAL DESIGN

Twenty patients ages > or = 65 years with metastatic breast, prostate, or lung cancer entered an Institutional Review Board-approved protocol to evaluate the pharmacokinetics of weekly docetaxel administered at 35 mg/m2 i.v. for 3 weeks followed by a 1-week break. The Erythromycin Breath Test and geriatric assessment were done before the first dose. Blood samples were collected for pharmacokinetic analysis with the first dose of docetaxel.

RESULTS

Of the 20 patients who entered the study, 19 were evaluable. There were no age-related differences in the pharmacokinetics of weekly docetaxel. Fifty-eight percent (11 of 19) experienced grade > or = 3 toxicity: 16% (3 of 19) grade > or = 3 hematologic toxicity, and 53% (10 of 19) grade > or = 3 nonhematologic toxicity. There was an association between the Erythromycin Breath Test results and docetaxel pharmacokinetic variables; however, there was no association between Erythromycin Breath Test results or docetaxel pharmacokinetics with frequency of grade > or = 3 toxicity.

CONCLUSIONS

Despite no statistically significant age-related differences in weekly docetaxel pharmacokinetics, over half of these older patients experienced a grade > or = 3 toxicity at the 35 mg/m2 starting dose. We advocate a starting dose of 26 mg/m2 on this weekly schedule and dose escalating if no toxicity.

Clinical outcomes by age in men with hormone refractory prostate cancer: a pooled analysis of 8 Cancer and Leukemia Group B (CALGB) studies

PURPOSE

We determined if age is a prognostic factor of clinical outcomes, specifically overall survival, disease-free survival and progression-free survival in men with hormone refractory prostate cancer.

MATERIALS AND METHODS

Data from 8 multi-institutional trials performed by Cancer and Leukemia Group B were combined. Eligible patients had progressive adenocarcinoma of the prostate after androgen ablation, Eastern Cooperative Oncology Group performance status 0 to 2, and adequate hematological, renal and hepatic function. The proportional hazards model stratified by study was used to assess the prognostic importance of age for predicting clinical outcomes.

RESULTS

Of 1,194 men 132 (11%) were 50 to 60 years old and 120 (10%) were 80 to 89 years old. Median survival was 12.2 months (95% CI 10.6 to 13.8) in men 50 to 59 years old, 15.9 months (95% CI 14.2 to 17.6) in men 60 to 69 years old, 15.6 months (95% CI 13.8 to 16.9) in men 70 to 79 years old and 8.9 months (95% CI 6.6 to 12.1) in men 80 to 89 years old. Compared to 70 to 79-year-old men the HR for death in octogenarians was 1.3 (95% CI 1.0 to 1.6, p = 0.015). Furthermore, the HR for prostate cancer death in octogenarians was 1.3 (95% CI 1.1 to 1.7, p = 0.010) and in 50 to 59-year-old men it was 1.3 (95% CI 1.0 to 1.6, p = 0.042) compared to men 70 to 79 years old. Black men were at lower risk for death than white men (HR 0.77, 95 CI% 0.65 to 0.92, p = 0.004).

CONCLUSIONS

Octogenarians and white men are at increased risk for death compared to other men with hormone refractory prostate cancer.

Histone deacetylase inhibitors: development as cancer therapy

Histone deacetylase (HDAC) inhibitors represent a new class of targeted anticancer agents. A number of structural classes of HDAC inhibitors have been developed of which several are in clinical trials, including phenylbutyrate (PB) and related compounds; the hydroxamic acids, suberoylanilide hydroxamic acid (SAHA) and depsipeptide (FK-228); and the benzamides, MS-275 and C1-994. This review will focus on our studies with the hydroxamic acid HDAC inhibitors, of which SAHA is the lead agent. X-ray crystallographic studies with a HDAC homologue (HDLP) demonstrated that the hydroxamic acid group, most of the aliphatic chain and part of the phenyl amino group of SAHA inserts into the pocket-like catalytic site of the enzyme, at the base of which is a zinc molecule. SAHA inhibits the activity of class I and II HDACs and is selective in altering gene expression. SAHA is synergistic in its anticancer activity with radiation, kinase inhibitors, cytotoxic agents and differentiating agents. In phase I clinical trial with orally administered SAHA the agent caused accumulation of acetylated histones in peripheral mononuclear cells and tumour cells, has excellent bioavailability and has shown antitumour activity in patients with haematologic and solid tumours.

Pilot study of epothilone B analog (BMS-247550) and estramustine phosphate in patients with progressive metastatic prostate cancer following castration

BACKGROUND

Several trials have demonstrated that the response proportions to microtubule agents in patients with prostate cancer are increased by the addition of estramustine phosphate (EMP). The epothilone B analog BMS-247550 is a novel microtubule agent that has shown activity in taxane-resistant tumors. We conducted a dose-escalation study to determine a safe dose of BMS-247550 to combine with EMP in patients with metastatic prostate cancer.

PATIENTS AND METHODS

Chemotherapy-naive patients with castrate-metastatic prostate cancer were treated with intravenous BMS-247550 and oral EMP (280 mg three times daily for 5 days) every 3 weeks.

RESULTS

Thirteen patients were treated at two dose levels (35 and 40 mg/m(2)). Three of six patients treated at 40 mg/m(2) developed grade 4 neutropenia, establishing 35 mg/m(2) as the maximum-tolerated dose. Significant peripheral neuropathy (grade >/= 2) was related to dose level and infusion rate. A decline in prostate-specific antigen (PSA) of >/= 50% was seen in 11 of 12 evaluable patients (92%) (95% confidence interval 76% to 100%). There were objective responses in soft tissue (57%) and bone metastasis (40%).

CONCLUSIONS

The phase II dose of BMS-247550 combined with EMP is 35 mg/m(2) over 3 h every 3 weeks. This combination is safe and >/= 50% post-therapy declines in PSA were seen in 11 of 12 patients (92%).

Phase I clinical trial of histone deacetylase inhibitor: suberoylanilide hydroxamic acid administered intravenously

PURPOSE

To evaluate the safety, pharmacokinetics, and biological activity of suberoylanilide hydroxamic acid (SAHA) administered by 2-h i.v. infusion in patients with advanced cancer.

EXPERIMENTAL DESIGN

SAHA was administered for 3 days every 21 days in part A and 5 days for 1-3 weeks in part B. Dose escalation proceeded independently in patients with solid tumor and hematological malignancies (part B only). Pharmacokinetic studies were performed along with assessment of acetylated histones in peripheral blood mononuclear cells and tumor tissues.

RESULTS

No dose-limiting toxicities were observed in 8 patients enrolled in part A (75, 150, 300, 600, and 900 mg/m(2)/day). Among 12 hematological and 17 solid tumor patients enrolled in part B (300, 600, and 900 mg/m(2)/day), therapy was delayed > or = 1 week for grade 3/4 leukopenia and/or thrombocytopenia in 2 of 5 hematological patients at 600 mg/m(2)/day x 5 days for 3 weeks. The maximal-tolerated dose was 300 mg/m(2)/day x 5 days for 3 weeks for hematological patients. One solid patient on 900 mg/m(2)/day x 5 days for 3 weeks developed acute respiratory distress and grade 3 hypotension. The cohort was expanded to 6 patients, and no additional dose-limiting toxicities were observed. Mean terminal half-life ranged from 21 to 58 min, and there was dose-proportional increase in area under the curve. An accumulation of acetylated histones in peripheral blood mononuclear cells up to 4 h postinfusion was observed at higher dose levels. Posttherapy tumor biopsies showed an accumulation of acetylated histones by immunohistochemistry. Four (2 lymphoma and 2 bladder) patients had objective tumor regression with clinical improvement in tumor related symptoms.

CONCLUSIONS

Daily i.v. SAHA is well tolerated, inhibits the biological target in vivo, and has antitumor activity in solid and hematological tumors.

Histone deacetylases and cancer: causes and therapies

Together, histone acetyltransferases and histone deacetylases (HDACs) determine the acetylation status of histones. This acetylation affects the regulation of gene expression, and inhibitors of HDACs have been found to cause growth arrest, differentiation and/or apoptosis of many tumours cells by altering the transcription of a small number of genes. HDAC inhibitors are proving to be an exciting therapeutic approach to cancer, but how do they exert this effect?

The Collection of Indirect and Nonmedical Direct Costs (COIN) form: a new tool for collecting the invisible costs of androgen independent prostate carcinoma

BACKGROUND

There are limited data available regarding the cost of care in patients with androgen independent prostate carcinoma (AIPC), and there are no data on the impact of direct nonmedical and indirect costs (DNM/IC). This lack of data, along with the feasibility of collecting DNM/IC, was examined in patients with AIPC who took part in a randomized trial using a newly developed questionnaire, the Collection of Indirect and Nonmedical Direct Costs (COIN) form.

METHODS

Patients with AIPC were randomized to one of three treatment arms: 1) strontium only (strontium 4 Mci in Week 1 and Week 12) (STRONT); 2) vinblastine 4 mg/m(2) per week for 3 weeks then 1 week off and estramustine, 10 mg/kg per day (CHEMO); or 3) a combination of treatments outlined in the arms for CHEMO and STRONT (CHEMO/STRONT). Direct medical costs were collected through the hospital billing system. DNM/IC data were obtained prospectively using the COIN form. Cost data were analyzed for a period of 6 months.

RESULTS

Twenty-nine patients were randomized, after which the protocol was closed because of poor accrual. The median survival of the patients was 22.3 months. The mean and median total costs for the 20 of 29 patients with complete cost information were $12,647 and $11,257 over 6 months, respectively. DNM/IC represented 11% of the total cost (range, from < 1% to 42%); in 20% of participating individuals, these costs accounted for 35-42% of total costs. Failure to collect complete cost information was due to early death, administrative difficulties, and loss to follow-up.

CONCLUSIONS

In this pilot project, the collection of these cost data using the COIN form was feasible and practical and was limited primarily by logistic, not form specific, issues. DNM/IC were found to be a significant proportion of total costs (up to 42%) in selected patients, and this information proved to be a useful addition to the cost analysis. Approximately 98 patients would be required to detect a 20% difference in total costs between arms in a properly powered, randomized trial. Considering the potentially significant impact on total costs, DNM/IC data should be included in future cost-analysis studies of patients with AIPC and other diseases.

Paclitaxel, estramustine phosphate, and carboplatin in patients with advanced prostate cancer

PURPOSE

To determine the safety and activity of weekly paclitaxel in combination with estramustine and carboplatin (TEC) in patients with advanced prostate cancer.

PATIENTS AND METHODS

In a dose-escalation study, patients with advanced prostate cancer were administered paclitaxel (weekly 1-hour infusions of 60 to 100 mg/m(2)), oral estramustine (10 mg/kg), and carboplatin (area under the curve, 6 mg/mL-min every 4 weeks). Paclitaxel levels were determined 0, 30, 60, 90, and 120 minutes and 18 hours after infusion, and a concentration-time curve was estimated. Once a safe dose was established, a multi-institutional phase II trial was conducted in patients with progressive androgen-independent disease.

RESULTS

Fifty-six patients with progressive androgen-independent disease were treated for a median of four cycles. The dose of paclitaxel was escalated from 60 to 100 mg/m(2) without the occurrence of DLT. Posttherapy decreases in serum prostate-specific antigen levels of 50%, 80%, and 90% were seen in 67%, 48%, and 39% (95% confidence interval, 55% to 79%, 35% to 61%, 26% to 52%) of the patients, respectively. Of the 33 patients with measurable disease, two (6%) had a complete response and 13 (39%) had a partial response. The overall median time to progression was 21 weeks, and the median survival time for all patients was 19.9 months. Major grade 3 or 4 adverse effects were thromboembolic disease (in 25% of patients), hyperglycemia (in 38%), and hypophosphatemia (in 42%). Significant leukopenia, thrombocytopenia, and peripheral neuropathy were not observed.

CONCLUSION

TEC has significant antitumor activity and is well tolerated in patients with progressive androgen-independent prostate cancer.

Prospective trial of the herbal supplement PC-SPES in patients with progressive prostate cancer

PURPOSE

PC-SPES is an herbal supplement for which there are anecdotal reports of anti-prostate cancer activity. This phase II study was undertaken to assess the efficacy and toxicity of PC-SPES in prostate cancer patients.

PATIENTS AND METHODS

Thirty-three patients with androgen-dependent prostate cancer (ADPCa) and 37 patients with androgen-independent prostate cancer (AIPCa) were treated with PC-SPES at a dose of nine capsules daily. Clinical outcome was assessed with serial serum prostate-specific androgen (PSA) level measurement and imaging studies.

RESULTS

One hundred percent of ADPCa patients experienced a PSA decline of >/= 80%, with a median duration of 57+ weeks. No patient has developed PSA progression. Thirty-one patients (97%) had declines of testosterone to the anorchid range. Two ADPCa patients had positive bone scans; both improved. One patient with a bladder mass measurable on computed tomography scan experienced disappearance of this mass. Nineteen (54%) of 35 AIPCa patients had a PSA decline of >/= 50%, including eight (50%) of 16 patients who had received prior ketoconazole therapy. Median time to PSA progression was 16 weeks (range, 2 to 69+ weeks). Of 25 patients with positive bone scans, two had improvement, seven had stable disease, 11 had progressive disease, and five did not have a repeat bone scan because of PSA progression. Severe toxicities included thromboembolic events (n = 3) and allergic reactions (n = 3). Other frequent toxicities included gynecomastia/gynecodynia, leg cramps, and grade 1 or 2 diarrhea.

CONCLUSION

PC-SPES seems to have activity in the treatment of both ADPCa and AIPCa and has acceptable toxicity. Further study is required to determine whether its effects exceed those expected with estrogen therapy.

Endocrine withdrawal syndrome and its relevance to the management of hormone refractory prostate cancer

Therapeutic options for patients with metastatic prostate cancer relapsing from primary hormonal therapy are limited. On the selective discontinuation of flutamide in patients that have relapsed on combined androgen ablation, a third of the patients will show a significant clinical benefit for 4-6 months. A multivariate model has identified prolonged exposure to combined androgen blockade, high baseline alkaline phosphatase and prolonged flutamide exposure as prognostic factors for patients that have a significant prostate-specific antigen (PSA) decline after the withdrawal of flutamide. This phenomenon has also been described with bicalutamide and other antiandrogens, and thus has been more appropriately renamed the endocrine withdrawal syndrome. The molecular basis for this endocrine withdrawal syndrome is not completely understood but data suggest that mutations in the androgen receptor may be responsible for the paradoxical effect observed. Recognition of this syndrome has introduced a non-toxic therapy for advanced prostate cancer patients and has had a dramatic impact on the interpretation and design of clinical trials in patients with 'hormone refractory disease'.

Chemotherapy for androgen- independent prostate cancer: myth or reality

In the past, the treatment options for patients with metastatic prostate cancer that progressed despite castrate levels of testosterone was limited, and no therapies provided an improvement in survival. The majority of these patients had extensive osseous disease, multiple comorbidities, and poor performance status. With the widespread use of prostate-specific antigen (PSA) to monitor their clinical course, patients have presented with less extensive disease and a better performance status. Clinical trial methodology has improved as well, through incorporation of post-therapy changes in PSA to evaluate novel agents. This approach allows more patients to enter clinical trials, and the results show that the majority of these patients will have significant reduction in pain, regression of measurable disease, and suppression of PSA. These data suggest that prostate cancer is not as resistant to chemotherapy as it was once thought to be.

Results of a phase II study using estramustine phosphate and vinblastine in combination with high-dose three-dimensional conformal radiotherapy for patients with locally advanced prostate cancer

PURPOSE

To assess the feasibility and tolerance of neoadjuvant and concomitant estramustine phosphate and vinblastine (EV) with high-dose three-dimensional conformal radiotherapy (3D-CRT) for patients with unfavorable-risk prostate cancer.

PATIENTS AND METHODS

Twenty-seven patients with unfavorable-risk prostate cancer were enrolled onto a prospective study to determine the feasibility of combining EV with 3D-CRT. Patients were eligible if any of the following requirements were satisfied: (1) Gleason score > or =8 and prostate-specific antigen (PSA) > 10 ng/mL; (2) Gleason score of 7 and PSA > 20 ng/mL; (3) clinical stage T3N0M0 disease with PSA > 20 ng/mL; (4) any patient with T4N0M0 disease; or (5) patients with TXN1MO disease. Therapy consisted of three 8-week cycles of EV and 8 weeks of 3D-CRT. Estramustine phosphate was given orally beginning on week 1 and continued until the completion of 3D-CRT. Each 8-week cycle of vinblastine consisted of 6 weekly intravenous injections followed by a 2-week rest period. Radiation therapy was administered using a three-dimensional conformal approach to a prescription dose of 75.6 Gy. The median follow-up was 26 months (range, 6 to 40 months).

RESULTS

Twenty-three (85%) of 27 patients completed the entire course of therapy and were assessable for toxicities and biochemical outcome. Two patients (7%) developed grade 3 hematologic toxicity that resolved, and two patients (7%) developed grade 3 hepatoxicity, manifesting as persistent elevation of serum transaminase levels, necessitating discontinuation of the chemotherapy and withdrawal from the treatment program. The most prominent adverse effects from this regimen were mild to moderate (grade 1 to 2) nausea and fatigue related to estramustine. Mild peripheral edema was seen in 15% of patients and was treated with diuresis. 3D-CRT was tolerated well in these patients. Medications were required for relief of acute grade 2 rectal (gastrointestinal [GI]) and urinary (genitourinary [GU]) symptoms in 35% and 48% of patients, respectively. Three patients developed acute grade 3 GU toxicities. The 2-year actuarial likelihood of late grade 2 GI toxicity was 20%. No late grade 3 or 4 GI toxicities were observed. The 2-year actuarial likelihoods of late grade 2 and 3 GU toxicities were 25% and 12%, respectively. No grade 4 GU toxicity was observed.

CONCLUSION

Neoadjuvant and concomitant EV with high-dose 3D-CRT is well tolerated in patients with unfavorable-risk prostate cancer. Although the incidence of modest (grade 2) late GI and GU toxicities seem to be increased compared with 3D-CRT alone or in combination with androgen ablation therapy, no severe toxicities were encountered with this regimen.

Ifosfamide, paclitaxel, and cisplatin for patients with advanced transitional cell carcinoma of the urothelial tract: final report of a phase II trial evaluating two dosing schedules

BACKGROUND

A combination regimen of ifosfamide, paclitaxel, and cisplatin (ITP), recycled every 4 weeks, was reported in the treatment of previously untreated patients with advanced transitional cell carcinoma (TCC). This study sought to examine ITP at 3-week intervals to assess its feasibility and toxicity, compare the results for different schedules, and assess the impact of prognostic factors and postchemotherapy surgery on outcome.

METHODS

ITP (ifosfamide 1.5 g/m(2) daily for 3 days, paclitaxel 200 mg/m(2) over 3 hours, and cisplatin 70 mg/m(2) on Day 1) was administered to patients with metastatic or unresectable TCC and was recycled every 4 weeks (for 30 patients) or 3 weeks (for 15 patients). Granulocyte-colony stimulating factor was given during each cycle.

RESULTS

Thirty of 44 assessable patients (68%; 95% confidence interval, 52-81%) demonstrated a major response (10 complete responses [23%], 20 partial [45%]), with durations of response ranging from 4 to 36 months. At a median follow-up of 28 months, the median survival was 20 months. Eleven patients (25%) were disease free at last follow-up. Overall toxicity for the 15 patients whose treatment was recycled at 3 weeks was similar to that for patients treated every 4 weeks. Hematologic toxicity included anemia, thrombocytopenia, and febrile neutropenia. Febrile neutropenia was observed in 7 patients (16%) and in 3.3% of cycles of therapy. No Grade 4 nonhematologic toxicity was observed. Grade 3 nonhematologic toxicity included alopecia, renal insufficiency (11%), and neuropathy (9%).

CONCLUSIONS

ITP is an active, well-tolerated regimen for previously untreated patients with TCC of the urothelial tract, resulting in a median survival of 20 months. Treatment can be recycled at 3-week intervals without enhanced toxicity.

The development of biologic end points in patients treated with differentiation agents: an experience of retinoids in prostate cancer

The evaluation of new therapies in prostate cancer requires unique end points for agents with diverse mechanisms of action. Because retinoic acid may have a confounding effect on prostate-specific antigen, we incorporated a pathological end point into the outcome assessment of two sequential clinical trials using all-trans-retinoic acid (ATRA) and the combination of 13-cis-retinoic acid and IFN-2a (cRA¿IFN). Pre- and posttherapy tumor biopsy specimens were studied for histological changes, apoptosis (terminal deoxynucleotidyl transferase-mediated nick end labeling assay), and proliferation index (Ki67). Prostate-specific membrane antigen (PSMA) expression was also evaluated using two different monoclonal antibodies to its intracellular domain (Cytogen 7E11 and Hybritech PM2). Fourteen patients with androgen-independent disease were treated with ATRA (50 mg/m2 p.o. every 8 h daily) and 16 androgen-independent and 4 androgen-dependent patients were treated with cRA¿IFN (10 mg/kg/day cRA plus 3, 6, or 9 million units daily IFN). Both therapies were well tolerated, with fatigue and cheilitis being the most common adverse events. Clinical activity, assessed by radiographs and serum prostate-specific antigen, was minimal, and the majority of patients progressed within 3 months. One patient with androgen-dependent disease had prolonged stabilization for >1 year. The majority of cases (95%) showed no gross histological changes and no difference in apoptotic or proliferative indices. Increased PSMA immunoreactivity was seen in seven of nine (78%) cases using PM2 antibody and in two of nine (22%) cases using the 7E11 antibody. Although antitumor effects were modest, the results suggest a role for retinoids in modulating the expression of PSMA on prostate cancer cells.

Phase I evaluation of sequential doxorubicin gemcitabine then ifosfamide paclitaxel cisplatin for patients with unresectable or metastatic transitional-cell carcinoma of the urothelial tract

PURPOSE

This phase I trial sought to evaluate the toxicity of and determine the maximum-tolerated dose (MTD) for the two-drug regimen doxorubicin and gemcitabine (AG) followed by the three-drug regimen of ifosfamide, paclitaxel, and cisplatin (ITP) in patients with unresectable or metastatic transitional-cell carcinoma.

PATIENTS AND METHODS

Patients received AG every other week for six cycles followed by ITP every 3 weeks for four cycles. Five AG dose levels were investigated, up to doxorubicin 50 mg/m(2) and gemcitabine 2, 000 mg/m(2), to determine the MTD of the regimen. The dose and schedule of ITP were constant: ifosfamide 1,500 mg/m(2) (days 1 to 3); paclitaxel 200 mg/m(2) (day 1); and cisplatin 70 mg/m(2) (day 1). Granulocyte colony-stimulating factor was given between all cycles of therapy.

RESULTS

Fifteen patients enrolled onto this phase I trial. AG was well tolerated at all dose levels, with no grade 3 or 4 myelosuppression. Toxicity experienced with ITP included grade 3 and 4 granulocytopenia in four patients and grade 3 nausea/vomiting in three patients. No grade 3 and 4 neurotoxicity was observed. Eight of 14 assessable patients experienced a major response to AG, including five of six patients treated at the two highest AG dose levels. After completion of AG-ITP, nine of 14 assessable patients had a major response (three complete responses and six partial responses).

CONCLUSION

AG is a well-tolerated and active regimen. Sequential chemotherapy with AG-ITP is also well tolerated, and phase II investigation at the highest dose level is ongoing.

Prognostic significance of extent of disease in bone in patients with androgen-independent prostate cancer

PURPOSE

To evaluate the prognostic significance of a bone scan index (BSI) based on the weighted proportion of tumor involvement in individual bones, in relation to other factors and to survival in patients with androgen-independent prostate cancer.

PATIENTS AND METHODS

Baseline radionuclide bone scans were reviewed in 191 assessable patients with androgen-independent disease who were enrolled onto an open, randomized trial of liarozole versus prednisone. The extent of skeletal involvement was assessed by scoring each scan using the BSI and independently according to the number of metastatic lesions. The relationship of the scored bone involvement to other known prognostic factors was explored in single- and multiple-variable analyses.

RESULTS

In single-variable analyses, the pretreatment factors found to be associated with survival were age (P = .0446), performance status (P = .0005), baseline prostate-specific antigen (P = .0001), hemoglobin (P = .0001), alkaline phosphatase (P = .0002), AST (P = .0021), lactate dehydrogenase (P = .0001), and treatment (P = .0098). The extent of osseous disease was significant using both the BSI (P = .0001) and the number of lesions present (P = .0001). In multiple-variable proportional hazards analyses, only BSI, age, hemoglobin, lactate dehydrogenase, and treatment arm were associated with survival. When the patient population was divided into three equal groups, with BSI values of < 1.4%, 1.4% to 5.1%, and > 5.1%, median survivals of 18.3, 15.5, and 8.1 months, respectively, were observed (P = .0079).

CONCLUSION

The BSI quantifies the extent of skeletal involvement by tumor. It allows the identification of patients with distinct prognoses for stratification in clinical trials. Further study is needed to assess the utility of serial BSI determinations in monitoring treatment effects. The BSI may be particularly useful in the evaluation of agents for which prostate-specific antigen changes do not reflect clinical outcomes accurately.

Small cell and anaplastic prostate cancer: correlation between CT findings and prostate-specific antigen level

PURPOSE

To evaluate the computed tomographic (CT) findings in patients with the anaplastic clinical variant of prostate cancer and to correlate these with prostate-specific antigen (PSA) levels.

MATERIALS AND METHODS

Twenty-seven men with the anaplastic clinical variant of prostate cancer, including 12 patients with small cell cancer of the prostate, underwent CT before platinum-based chemotherapy. CT findings were retrospectively reviewed for the extent of disease in the abdominal and pelvic lymph nodes, liver, bone, and prostate. CT findings were correlated with baseline PSA levels.

RESULTS

The overall mean PSA level was 59.9 ng/ml +/- 23.3 (range, 0-583 ng/ml; median, 4 ng/ml), with a mean PSA level in the small cell cancer subgroup of 12.3 ng/ml +/- 9.0 (range, 0-110 ng/mL; median, 1.7 ng/mL). Twenty-six patients (96%) had metastatic disease evident at CT, but only nine (33%) had PSA levels greater than 10 ng/mL. The mean PSA level in patients with pelvic lymphadenopathy was 12.8 ng/mL +/- 7.9 (median, 1.6 ng/mL); that in the small cell cancer subgroup was only 2.8 ng/ml +/- 1.4 (median, 1.6 ng/ml). Whereas 19 (70%) of all patients had osseous metastases and an average PSA level of 73 ng/ml +/- 32(median, 9.1 ng/mL), the seven (58%) with small cell cancer and bone metastases had an average PSA level of 18 ng/mL +/- 13 (median, 4 ng/mL).

CONCLUSION

Unlike patients with advanced typical adenocarcinoma of the prostate, patients with the anaplastic clinical variant of prostate cancer often have extensive metastatic disease at CT despite relatively low PSA levels.

Treatment of patients with transitional-cell carcinoma of the urothelial tract with ifosfamide, paclitaxel, and cisplatin: a phase II trial

PURPOSE

A phase II trial of ifosfamide, paclitaxel, and cisplatin (ITP) was conducted in previously untreated patients with advanced transitional-cell carcinoma (TCC) to assess its efficacy and toxicity.

PATIENTS AND METHODS

Thirty patients with metastatic or unresectable TCC were treated with ifosfamide 1.5 g/m2/d for 3 days with paclitaxel 200 mg/m2 over 3 hours and cisplatin 70 mg/m2 on day 1 of each 28-day treatment cycle. Therapy was continued for a maximum of six cycles. Prophylactic hematopoietic growth factor (recombinant human granulocyte colony-stimulating factor [rhG-CSF]) was given on days 6 to 17 of each cycle.

RESULTS

Twenty-three of 29 assessable patients (79%; 95% confidence interval [CI], 60% to 92%) demonstrated a major response (six complete [CR] and 17 partial [PR]) with response durations that ranged from 5 to 24+ months. Five patients with T4 bladder primary tumors had a major response, two with pathologic CR. At a median follow-up duration of 17.9 months, nine (31%) patients remain disease-free (range, 10+ to 24+). Hematologic toxicity included anemia, thrombocytopenia, and neutropenia; febrile neutropenia was observed in 17% of patients and 4% of cycles. No grade 4 nonhematologic toxicity was observed. Grade 3 nonhematologic toxicity included alopecia, allergy (3%), renal insufficiency (13%), and neuropathy (10%). Dose reductions or drug omissions were necessary for adverse events in seven (23%) patients.

CONCLUSION

ITP is an active, well-tolerated regimen in previously untreated patients with TCC of the urothelial tract. Further study of this regimen in patients with both TCC and non-transitional-cell urothelial tumors is ongoing.

Localized squamous cell carcinoma of the bladder causing hypercalcemia and inhibition of PTH secretion

We report a case of symptomatic hypercalcemia in a patient with muscle-invasive, resectable squamous cell carcinoma of the bladder. Serum parathyroid hormone was consistent with secretion of parathyroid hormone-related protein. After radical cystoprostatectomy, calcium levels returned to normal. Patients with squamous cell carcinoma and an abnormal serum calcium level may have localized disease and should not be denied definitive local therapy.

Immunological approaches for the treatment of prostate cancer

Conventional therapies for patients with early-stage relapsed prostate cancer often do not provide an acceptable quality of life. These patients often have increasing PSAs as the sole manifestation of their disease recurrence and represent a unique subgroup of patients for whom alternative treatment strategies are needed. The patients are asymptomatic and may be an appropriate population for targeted immunological approaches. Vaccine therapies, based on synthetically constructed, naturally occurring prostate-associated antigens or genetically modified immune cells, offer exciting new approaches toward treating this disease with resulting antitumor effects and minimal toxicities. The results of clinical trials using these technologies reinforces the use of immunological approaches for the treatment of prostate cancer.

Bicalutamide for advanced prostate cancer: the natural versus treated history of disease

PURPOSE

To determine the therapeutic effects of bicalutamide 200 mg in patients with prostate cancers of different hormone sensitivities.

METHODS

Patients with progressive prostate cancer were treated with bicalutamide 200 mg daily. Before treatment, patients' tumors were classified on the basis of prior hormone exposure and by serum testosterone levels into androgen-dependent and androgen-independent groups. Prior exposure to flutamide and response to flutamide withdrawal was also considered. Outcomes were reported independently on the basis of posttherapy changes in prostate-specific antigen (PSA), measurable disease, and radionuclide bone scans.

RESULTS

Outcomes varied by prior hormone exposure as a higher proportion of patients with progression of androgen-dependent tumors showed posttherapy PSA decreases of more than 50% or more than 80%, measurable disease regression, and improvement on radionuclide bone scans than did patients with androgen-independent progression. Within the category of androgen-independent progression, clinical benefit was observed in patients who had previously progressed on flutamide, independent of the response to flutamide withdrawal. Patients who had progressed on a gonadotropin-releasing hormone (GnRH) analog alone had a low response proportion, whereas those who progressed after two or more hormone therapies did not respond. Overall, the drug was well tolerated. After progression on bicalutamide monotherapy, one third of patients with androgen-dependent progression responded to medical castration with a GnRH analog.

CONCLUSION

Classifying patient tumors on the basis of prior hormone exposure permits a more precise estimate of the potential benefit of a specific hormone therapy for the individual patient. The precision is further increased by reporting the effects of a drug on each parameter of disease independently. The difference in outcomes for patients with androgen-independent progression suggests that the specific hormone therapy administered and the response to that therapy can influence the biology of the relapsing tumor and the sensitivity to subsequent therapies. The sensitivity to bicalutamide after progression on flutamide deserves further study.

Phase II randomized trial of gallium nitrate plus fluorouracil versus methotrexate, vinblastine, doxorubicin, and cisplatin in patients with advanced transitional-cell carcinoma

PURPOSE

A phase II randomized trial of gallium nitrate/fluorouracil (5-FU) versus dose-intense methotrexate, vinblastine, doxorubicin, and cisplatin (M-VAC) was performed in poor-risk patients with advanced urothelial tract tumors. The efficacy and toxicity of these regimens were compared. Assessment of dose-intense M-VAC as salvage treatment in patients who failed to respond to the gallium nitrate/5-FU regimen was also performed.

PATIENTS AND METHODS

Thirty-four patients who had not received prior systemic chemotherapy were randomized to either arm of the study. All patients had one or more clinical features predicting a low likelihood of durable complete response to standard chemotherapy, ie, weight loss, visceral metastases, and low performance status. Gallium nitrate and 5-FU were each administered by continuous 5-day infusions every 28 days. M-VAC was recycled every 21 days, with prophylactic recombinant human granulocyte colony-stimulating factor (rh-G-CSF).

RESULTS

Two of 17 patients (12%; 95% confidence interval [CI], 1.4% to 36.4%) had a major response to gallium nitrate/5-FU. Sixteen of 17 patients treated with M-VAC (94%; 95% CI, 71.3% to 99.8%) demonstrated a major response. Five of 12 patients who failed to respond to the gallium nitrate/5-FU combination responded to M-VAC as second-line therapy (42%; 95% CI, 15.2% to 72.3%). Median survival for the gallium nitrate and 5-FU arm was 19 versus 17 months for the M-VAC arm, with a median follow-up duration of 35 months (range, 2 to 51) for all patients. Dose-intense M-VAC was associated with a greater incidence of neutropenia and thrombocytopenia.

CONCLUSION

Dose-intense M-VAC is superior to gallium nitrate/5-FU in poor-risk patients (P < .0001). Despite the overall high response rate, the median survival for patients with M-VAC remained unsatisfactory. Similar survival distributions were observed for patients who received investigational therapy followed by cisplatin-based therapy and patients treated with initial cisplatin-based therapy.

Steroid hormone withdrawal syndromes. Pathophysiology and clinical significance

The steroid withdrawal syndrome has brought a new dimension to the treatment of advanced prostate cancer not only in the way we treat androgen-independent disease but also in terms of insights into the development of hormonal resistance. The data now confirm that 30% of cases have a meaningful subjective, biochemical, and objective response to the withdrawal of a steroid hormone as the first maneuver after primary hormonal therapy failure. Larger studies are needed to define further the withdrawal effect related to the other steroid hormone family members and to determine the objective response proportions. Although controversy surrounds the cause of the steroid withdrawal phenomenon, studies suggest that the androgen receptor plays a pivotal role. Molecular studies of the androgen receptors involving larger number of patients are paramount if we are going to develop a better understanding of the evolution of the withdrawal effect and hormone resistance.

Phase II trial of docetaxel in patients with advanced or metastatic transitional-cell carcinoma

PURPOSE

A phase II trial of docetaxel was conducted to assess its efficacy and toxicity in patients with advanced transitional-cell carcinoma (TCC) who had failed to respond to prior cisplatin-based therapy.

PATIENTS AND METHODS

Thirty assessable patients who had failed to respond to or relapsed after one prior cisplatin-containing regimen were treated with docetaxel 100 mg/m2 over 1 hour, every 21 days. All patients were premedicated with dexamethasone and diphenhydramine to reduce allergic reactions. Reductions of subsequent doses were made for severe hematologic toxicity. Prophylactic hematopoietic growth factors were not used.

RESULTS

Four of 30 patients (13.3%; 95% confidence interval [CI], 3.8% to 30.7%) demonstrated a partial response (PR), with durations of response ranging from 3 to 8 months. The estimated median survival duration for all patients is 9 months (95% CI, 6 to 12 months) with a median follow-up time of 14 months (range, 1 to 27). Hematologic toxicity included anemia, thrombocytopenia, neutropenia, and febrile neutropenia. Nonhematologic toxicity included alopecia and mucositis. Fluid retention was not observed and cutaneous toxicity was mild and infrequent. Dose reductions were necessary for adverse events in 18 patients (60%).

CONCLUSION

Docetaxel is an active single agent in previously treated patients with TCC of the urothelial tract. Therapy was well tolerated in this patient population but myelosuppression was frequent. Further study in previously untreated patients, both alone and in combination, is warranted.