An open-label, single-arm, phase 2 trial of the Polo-like kinase inhibitor volasertib (BI 6727) in patients with locally advanced or metastatic urothelial cancer

BACKGROUND

Polo-like kinases (Plks) control multiple steps during the cell cycle, and Plk1 is overexpressed in urothelial cancer (UC). Volasertib (BI 6727), a Plk inhibitor, has demonstrated antitumor activity in several malignancies, including UC. In this phase 2 trial, the authors investigated volasertib as a second-line treatment in advanced/metastatic UC.

METHODS

Patients who progressed within 2 years of 1 prior chemotherapy regimen received 300 mg volasertib on day 1 every 3 weeks. The dose was escalated to 350 mg in cycle 2 if volasertib was tolerated in cycle 1. The primary endpoint was tumor response, which was assessed every 6 weeks; secondary endpoints were progression-free survival, overall survival, duration of response, safety, and pharmacokinetics.

RESULTS

Fifty patients were enrolled, and the median patient age was 68.5 years (range, 52-83 years). All patients had received prior platinum, 94% of patients had relapsed ≤2 years after prior therapy, 36% had liver metastases, and 54% had lung metastases. The median number of treatment cycles was 2 (range, 1-27 treatment cycles), and 23 patients were dose escalated at cycle 2. Seven patients (14%) had a partial response, 13 (26%) had stable disease, and 30 (60%) progressed within 6 weeks. The median response duration was 41 weeks (range, 29.1-77.3 weeks). The median progression-free survival was 1.4 months, and the median overall survival was 8.5 months. The most frequent grade 3 and 4 adverse events were neutropenia (28%), thrombocytopenia (20%), and anemia (16%). No cumulative toxicity was observed.

CONCLUSIONS

Volasertib as second-line treatment for advanced/metastatic UC had an acceptable safety profile but demonstrated insufficient antitumor activity for further evaluation as a monotherapy.

Active smoking may negatively affect response rate, progression-free survival, and overall survival of patients with metastatic renal cell carcinoma treated with sunitinib

BACKGROUND

Obesity, smoking, hypertension, and diabetes are risk factors for renal cell carcinoma development. Their presence has been associated with a worse outcome in various cancers. We sought to determine their association with outcome of sunitinib treatment in metastatic renal cell carcinoma (mRCC).

METHODS

An international multicenter retrospective study of sunitinib-treated mRCC patients was performed. Multivariate analyses were performed to determine the association between outcome and the pretreatment status of smoking, body mass index, hypertension, diabetes, and other known prognostic factors.

RESULTS

Between 2004 and 2013, 278 mRCC patients were treated with sunitinib: 59 were active smokers, 67 were obese, 73 were diabetic, and 165 had pretreatment hypertension. Median progression-free survival (PFS) was 9 months, and overall survival (OS) was 22 months. Factors associated with PFS were smoking status (past and active smokers: hazard ratio [HR]: 1.17, p = .39; never smokers: HR: 2.94, p < .0001), non-clear cell histology (HR: 1.62, p = .011), pretreatment neutrophil-to-lymphocyte ratio >3 (HR: 3.51, p < .0001), use of angiotensin system inhibitors (HR: 0.63, p = .01), sunitinib dose reduction or treatment interruption (HR: 0.72, p = .045), and Heng risk (good and intermediate risk: HR: 1.07, p = .77; poor risk: HR: 1.87, p = .046). Factors associated with OS were smoking status (past and active smokers: HR: 1.25, p = .29; never smokers: HR: 2.7, p < .0001), pretreatment neutrophil-to-lymphocyte ratio >3 (HR: 2.95, p < .0001), and sunitinib-induced hypertension (HR: 0.57, p = .002).

CONCLUSION

Active smoking may negatively affect the PFS and OS of sunitinib-treated mRCC. Clinicians should consider advising patients to quit smoking at initiation of sunitinib treatment for mRCC.

Management of patients with biochemical recurrence after local therapy for prostate cancer

Nearly three-quarters of a million American men who have been treated with prostatectomy and/or radiation therapy experience an increasing prostate-specific antigen level known as biochemical recurrence. Although androgen-deprivation therapy remains a reasonable option for some men with biochemical recurrence, deferring androgen ablation or offering nonhormonal therapies may be appropriate in patients in whom the risk of clinical or metastatic progression and prostate cancer-specific death is low. A risk-stratified approach informed by the patient's prostate-specific antigen kinetics, comorbidities, and personal preferences is recommended to determine the best management approach.

Long-term survival and biomarker correlates of tasquinimod efficacy in a multicenter randomized study of men with minimally symptomatic metastatic castration-resistant prostate cancer

PURPOSE

Tasquinimod (Active Biotech) is an oral immunomodulatory, anti-angiogenic, and anti-metastatic agent that delayed metastatic disease progression in a randomized placebo-controlled phase II trial in men with metastatic castration-resistant prostate cancer (mCRPC). Here, we report long-term survival with biomarker correlates from this trial.

EXPERIMENTAL DESIGN

Two hundred and one (134 tasquinimod and 67 placebo) men with mCRPC were evaluated. Forty-one men randomized to placebo crossed over to tasquinimod. Survival data were collected with a median follow-up time of 37 months. Exploratory biomarker studies at baseline and over time were collected to evaluate potential mechanism-based correlates with tasquinimod efficacy including progression-free survival (PFS) and overall survival (OS).

RESULTS

With 111 mortality events, median OS was 33.4 months for tasquinimod versus 30.4 months for placebo overall, and 34.2 versus 27.1 months in men with bone metastases (n = 136), respectively. Multivariable analysis demonstrated an adjusted HR of 0.52 [95% confidence interval (CI), 0.35-0.78; P = 0.001] for PFS and 0.64 (95% CI, 0.42-0.97; P = 0.034) for OS, favoring tasquinimod. Time-to-symptomatic progression was improved with tasquinimod (P = 0.039, HR = 0.42). Toxicities tended to be mild in nature and improved over time. Biomarker analyses suggested a favorable impact on bone alkaline phosphatase and lactate dehydrogenase (LDH) over time and a transient induction of inflammatory biomarkers, VEGF-A, and thrombospondin-1 levels with tasquinimod. Baseline levels of thrombospondin-1 less than the median were predictive of treatment benefit.

CONCLUSIONS

The survival observed in this trial of men with minimally symptomatic mCRPC suggests that the prolongation in PFS with tasquinimod may lead to a survival advantage in this setting, particularly among men with skeletal metastases, and has a favorable risk:benefit ratio.

Targeting prostate cancer cell lines with polo-like kinase 1 inhibitors as a single agent and in combination with histone deacetylase inhibitors

Combinations of anticancer therapies with high efficacy and low toxicities are highly sought after. Therefore, we studied the effect of polo-like kinase 1 (Plk1) inhibitors on prostate cancer cells as a single agent and in combination with histone deacetylase (HDAC) inhibitors valproic acid and vorinostat. IC50s of Plk1 inhibitors BI 2536 and BI 6727 were determined in prostate cancer cells by MTS assays. Morphological and molecular changes were assessed by immunoblotting, immunofluorescence, flow cytometry, real-time RT-PCR, and pulldown assays. Efficacy of combination therapy was assessed by MTS and clonogenic assays. IC50 values in DU145, LNCaP, and PC3 cells were 50, 75, and 175 nM, respectively, for BI 2536 and 2.5, 5, and 600 nM, respectively, for BI 6727. Human prostate fibroblasts and normal prostate epithelial cells were unaffected at these concentrations. While DU145 and LNCaP cells were solely arrested in mitosis on treatment, PC3 cells accumulated in G2 phase and mitosis, suggesting a weak spindle assembly checkpoint. Combining Plk1 inhibitors with HDAC inhibitors had synergistic antitumor effects in vitro. DMSO-treated prostate cancer cells were used as controls to study the effect of Plk1 and HDAC inhibition. Plk1 inhibitors decreased proliferation and clonogenic potential of prostate cancer cells. Hence, Plk1 may serve as an important molecular target for inhibiting prostate cancer. Combining HDAC inhibitors with BI 2536 or BI 6727 may be an effective treatment strategy against prostate cancer.

Docetaxel and atrasentan versus docetaxel and placebo for men with advanced castration-resistant prostate cancer (SWOG S0421): a randomised phase 3 trial

BACKGROUND

The endothelin pathway has a role in bone metastases, which are characteristic of advanced prostate cancer. Atrasentan, an endothelin receptor antagonist, has shown activity in prostate cancer. We therefore assessed its effect on survival in patients with castration-resistant prostate cancer with bone metastases.

METHODS

In a double-blind phase 3 trial, men with metastatic castration-resistant prostate cancer, stratified for progression type (prostate-specific antigen or radiological), baseline pain, extraskeletal metastases, and bisphosphonate use, were randomly assigned in a 1:1 ratio to docetaxel (75 mg/m(2) every 21 days, intravenously) with atrasentan (10 mg/day, orally) or placebo for up to 12 cycles and treated until disease progression or unacceptable toxicity. Patients who did not progress on treatment were permitted to continue atrasentan or placebo for up to 52 weeks. Coprimary endpoints were progression-free survival (PFS) and overall survival. Analysis was by intention to treat. This trial is registered with ClinicalTrials.gov, number NCT00134056.

FINDINGS

498 patients were randomly assigned to the atrasentan group and 496 to the placebo group. The trial was halted early for futility in April, 2011, after a planned interim analysis. Median PFS was 9·2 months (95% CI 8·5-9·9) in the atrasentan group and 9·1 months (8·4-10·2) in the placebo group (hazard ratio 1·02, 0·89-1·16; p=0·81). Median overall survival was 17·8 months (16·4-19·8) in the atrasentan group versus 17·6 months (16·4-20·1) in the placebo group (1·04, 0·90-1·19; p=0·64). 278 (57%) of 492 patients in the atrasentan group had grade 3 and greater toxicity compared with 294 (60%) of 486 in the placebo group (p=0·22). Three deaths in the atrasentan group and seven in the placebo group were judged to be possibly or probably due to protocol treatment.

INTERPRETATION

Atrasentan, when added to docetaxel, does not improve overall survival or PFS in men with castration-resistant prostate cancer and bone metastases; therefore, single-agent docetaxel should remain as one of the standard treatments.

FUNDED

National Cancer Institute, Sanofi-Aventis, and Abbott Laboratories.

Screening assay for blood vessel maturation inhibitors

In cancer patients, the development of resistance to anti-angiogenic agents targeting the VEGF pathway is common. Increased pericyte coverage of the tumor vasculature undergoing VEGF targeted therapy has been suggested to play an important role in resistance. Therefore, reducing the pericytes coverage of the tumor vasculature has been suggested to be a therapeutic approach in breaking the resistance to and increasing the efficacy of anti-angiogenic therapies. To screen compound libraries, a simple in vitro assay of blood vessel maturation demonstrating endothelial cells and pericytes association while forming lumenized vascular structures is needed. Unfortunately, previously described 3-dimensional, matrix based assays are laborious and challenging from an image and data acquisition perspective. For these reasons they generally lack the scalability needed to perform in a high-throughput environment. With this work, we have developed a novel in vitro blood vessel maturation assay, in which lumenized, vascular structures form in one optical plane and mesenchymal progenitor cells (10T1/2) differentiate into pericyte-like cells, which associate with the endothelial vessels (HUVECs). The differentiation of the 10T1/2 cells into pericyte-like cells is visualized using a GFP reporter controlled by the alpha smooth muscle actin promoter (SMP-8). The organization of these vascular structures and their recruited mural cells in one optical plane allows for automated data capture and subsequent image analysis. The ability of this assay to screen for inhibitors of pericytes recruitment was validated. In summary, this novel assay of in vitro blood vessel maturation provides a valuable tool to screen for new agents with therapeutic potential.

Analysis of the genomic response of human prostate cancer cells to histone deacetylase inhibitors

Histone deacetylases (HDACs) have emerged as important targets for cancer treatment. HDAC-inhibitors (HDACis) are well tolerated in patients and have been approved for the treatment of patients with cutaneous T-cell lymphoma (CTCL). To improve the clinical benefit of HDACis in solid tumors, combination strategies with HDACis could be employed. In this study, we applied Analysis of Functional Annotation (AFA) to provide a comprehensive list of genes and pathways affected upon HDACi-treatment in prostate cancer cells. This approach provides an unbiased and objective approach to high throughput data mining. By performing AFA on gene expression data from prostate cancer cell lines DU-145 (an HDACi-sensitive cell line) and PC3 (a relatively HDACi-resistant cell line) treated with HDACis valproic acid or vorinostat, we identified biological processes that are affected by HDACis and are therefore potential treatment targets for combination therapy. Our analysis revealed that HDAC-inhibition resulted among others in upregulation of major histocompatibility complex (MHC) genes and deregulation of the mitotic spindle checkpoint by downregulation of genes involved in mitosis. These findings were confirmed by AFA on publicly available data sets from HDACi-treated prostate cancer cells. In total, we analyzed 375 microarrays with HDACi treated and non-treated (control) prostate cancer cells. All results from this extensive analysis are provided as an online research source (available at the journal's website and at http://luigimarchionni.org/HDACIs.html). By publishing this data, we aim to enhance our understanding of the cellular changes after HDAC-inhibition, and to identify novel potential combination strategies with HDACis for the treatment of prostate cancer patients.

A non-comparative randomized phase II study of 2 doses of ATN-224, a copper/zinc superoxide dismutase inhibitor, in patients with biochemically recurrent hormone-naïve prostate cancer

OBJECTIVE

ATN-224 (choline tetrathiomolybdate) is an oral Cu(2+)/Zn(2+)-superoxide dismutase 1 (SOD1) inhibitor with preclinical antitumor activity. We hypothesized that ATN-224 may induce antitumor effects as an antiangiogenic agent at low dose-levels while possessing direct antitumor activity at higher dose-levels. The objective of this study was to screen its clinical activity in patients with biochemically recurrent hormone-naïve prostate cancer.

METHODS

Biochemically-recurrent prostate cancer patients with prostate specific antigen doubling times (PSADT) < 12 months, no radiographic evidence of metastasis, and no hormonal therapy within 6 months (with serum testosterone levels > 150 ng/dl) were eligible. ATN-224 was administered at 2 dose-levels, 300 mg (n = 23) or 30 mg (n = 24) daily, by way of randomization. PSA progression was defined as a ≥ 50% increase (and >5 ng/ml) in PSA from baseline or post-treatment nadir. Endpoints included the proportion of patients who were free of PSA progression at 24 weeks, changes in PSA slope/PSADT, and safety. The study was not powered to detect differences between the 2 treatment groups.

RESULTS

At 24 weeks, 59% (95% CI 33%-82%) of men in the low-dose arm and 45% (95% CI 17%-77%) in the high-dose arm were PSA progression-free. Median PSA progression-free survival was 30 weeks (95% CI 21-40(+)) and 26 weeks (95% CI 24-39(+)) in the low-dose and high-dose groups, respectively. Pre- and on-treatment PSA kinetics analyses showed a significant mean PSA slope decrease (P = 0.006) and a significant mean PSADT increase (P = 0.032) in the low-dose arm only. Serum ceruloplasmin levels, a biomarker for ATN-224 activity, were lowered in the high-dose group, but did not correlate with PSA changes.

CONCLUSIONS

Low-dose ATN-224 (30 mg daily) may have biologic activity in men with biochemically-recurrent prostate cancer, as suggested by an improvement in PSA kinetics. However, the clinical significance of PSA kinetics changes in this patient population remains uncertain. The absence of a dose-response effect also reduces enthusiasm, and there are currently no plans to further develop this agent in prostate cancer.

Prevalence of pain and analgesic use in men with metastatic prostate cancer using a patient-reported outcome measure

PURPOSE

Contemporary tumor-directed therapies for metastatic castration-resistant prostate cancer (mCRPC) are approved to prolong life, but their effects on symptoms such as pain are less well understood as a result of the lack of analytically valid assessments of pain prevalence and severity, clinically meaningful definitions of therapeutic benefit, and methodologic standards of trial conduct. This study establishes pain characteristics in the mCRPC population using a PRO measure.

MATERIALS AND METHODS

Patients with prostate cancer participated in an anonymous survey at five US comprehensive cancer centers in the Prostate Cancer Clinical Trials Consortium that incorporated the Brief Pain Inventory (BPI), analgesic use, and interference with daily activities. Prevalence and severity of cancer-related pain and analgesic use were tabulated according to castration-resistant status and exposure to docetaxel chemotherapy.

RESULTS

Four hundred sixty-one patients with prostate cancer participated, of whom 147 had mCRPC involving bone (61% [89 of 147] docetaxel exposed, 39% [58 of 147] docetaxel naive). Pain of any level was more common among docetaxel-exposed versus docetaxel-naive patients with mCRPC (70% [62 of 89] v 38% [22 of 58], respectively; P<.001). BPI score≥4 was reported by 38% (34 of 89) of docetaxel-pretreated and 24% (14 of 58) of docetaxel-naive patients with mCRPC; 40% of these patients with pain intensity≥4 reported no current narcotic analgesic.

CONCLUSION

Pain prevalence and severity were higher in patients with prior docetaxel exposure. Analgesics were underutilized. These results provide a method for estimating accruals along the disease continuum, and for enabling design of trials appropriately powered to assess pain.

Using the EORTC-QLQ-C30 in clinical practice for patient management: identifying scores requiring a clinician's attention

PURPOSE

Patient-reported outcomes (PROs) are used increasingly for individual patient management. Identifying which PRO scores require a clinician's attention is an ongoing challenge. Previous research used a needs assessment to identify EORTC-QLQ-C30 cutoff scores representing unmet needs. This analysis attempted to replicate the previous findings in a new and larger sample.

METHODS

This analysis used data from 408 Japanese ambulatory breast cancer patients who completed the QLQ-C30 and Supportive Care Needs Survey-Short Form-34 (SCNS-SF34). Applying the methods used previously, SCNS-SF34 item/domain scores were dichotomized as no versus some unmet need. We calculated area under the receiver operating characteristic curve (AUC) to evaluate QLQ-C30 scores' ability to discriminate between patients with no versus some unmet need based on SCNS-SF34 items/domains. For QLQ-C30 domains with AUC ≥ 0.70, we calculated the sensitivity, specificity, and predictive value of various cutoffs for identifying unmet needs. We hypothesized that compared to our original analysis, (1) the same six QLQ-C30 domains would have AUC ≥ 0.70, (2) the same SCNS-SF34 items would be best discriminated by QLQ-C30 scores, and (3) the sensitivity and specificity of our original cutoff scores would be supported.

RESULTS

The findings from our original analysis were supported. The same six domains with AUC ≥ 0.70 in the original analysis had AUC ≥ 0.70 in this new sample, and the same SCNS-SF34 item was best discriminated by QLQ-C30 scores. Cutoff scores were identified with sensitivity ≥0.84 and specificity ≥0.54.

CONCLUSION

Given these findings' concordance with our previous analysis, these QLQ-C30 cutoffs could be implemented in clinical practice and their usefulness evaluated.

Quality of care for comorbid conditions during the transition to survivorship: differences between cancer survivors and noncancer controls

PURPOSE

Building on previous research documenting differences in preventive care quality between cancer survivors and noncancer controls, this study examines comorbid condition care.

METHODS

Using data from the Surveillance, Epidemiology, and End Results (SEER) -Medicare database, we examined comorbid condition quality of care in patients with locoregional breast, prostate, or colorectal cancer diagnosed in 2004 who were age ≥ 66 years at diagnosis, who had survived ≥ 3 years, and who were enrolled in fee-for-service Medicare. Controls were frequency matched to cases on age, sex, race, and region. Quality of care was assessed from day 366 through day 1,095 postdiagnosis using published indicators of chronic (n = 10) and acute (n = 19) condition care. The proportion of eligible cancer survivors and controls who received recommended care was compared by using Fisher's exact tests. The chronic and acute indicators, respectively, were then combined into single logistic regression models for each cancer type to compare survivors' care receipt to that of controls, adjusting for clinical and sociodemographic variables and controlling for within-patient variation.

RESULTS

The sample matched 8,661 cancer survivors to 17,322 controls (mean age, 75 years; 65% male; 85% white). Colorectal cancer survivors were less likely than controls to receive appropriate care on both the chronic (odds ratio [OR], 0.88; 95% CI, 0.81 to 0.95) and acute (OR, 0.72; 95% CI, 0.61 to 0.85) indicators. Prostate cancer survivors were more likely to receive appropriate chronic care (OR, 1.28; 95% CI, 1.19 to 1.38) but less likely to receive quality acute care (OR, 0.75; 95% CI, 0.65 to 0.87). Breast cancer survivors received care equivalent to controls on both the chronic (OR, 1.06; 95% CI, 0.96 to 1.17) and acute (OR, 0.92; 95% CI, 0.76 to 1.13) indicators.

CONCLUSION

Because we found differences by cancer type, research exploring factors associated with these differences in care quality is needed.

Biodistribution, tumor detection, and radiation dosimetry of 18F-DCFBC, a low-molecular-weight inhibitor of prostate-specific membrane antigen, in patients with metastatic prostate cancer

Prostate-specific membrane antigen (PSMA) is a type II integral membrane protein expressed on the surface of prostate cancer (PCa) cells, particularly in androgen-independent, advanced, and metastatic disease. Previously, we demonstrated that N-[N-[(S)-1,3-dicarboxypropyl]carbamoyl]-4-(18)F-fluorobenzyl-L-cysteine ((18)F-DCFBC) could image an experimental model of PSMA-positive PCa using PET. Here, we describe the initial clinical experience and radiation dosimetry of (18)F-DCFBC in men with metastatic PCa.

METHODS

Five patients with radiologic evidence of metastatic PCa were studied after the intravenous administration of 370 MBq (10 mCi) of (18)F-DCFBC. Serial PET was performed until 2 h after administration. Time-activity curves were generated for selected normal tissues and metastatic foci. Radiation dose estimates were calculated using OLINDA/EXM 1.1.

RESULTS

Most vascular organs demonstrated a slow decrease in radioactivity concentration over time consistent with clearance from the blood pool, with primarily urinary radiotracer excretion. Thirty-two PET-positive suspected metastatic sites were identified, with 21 concordant on both PET and conventional imaging for abnormal findings compatible with metastatic disease. Of the 11 PET-positive sites not identified on conventional imaging, most were within the bone and could be considered suggestive for the detection of early bone metastases, although further validation is needed. The highest mean absorbed dose per unit administered radioactivity (μGy/MBq) was in the bladder wall (32.4), and the resultant effective dose was 19.9 ± 1.34 μSv/MBq (mean ± SD).

CONCLUSION

Although further studies are needed for validation, our findings demonstrate the potential of (18)F-DCFBC as a new positron-emitting imaging agent for the detection of metastatic PCa. This study also provides dose estimates for (18)F-DCFBC that are comparable to those of other PET radiopharmaceuticals such as (18)F-FDG.

Repurposing itraconazole as a treatment for advanced prostate cancer: a noncomparative randomized phase II trial in men with metastatic castration-resistant prostate cancer

BACKGROUND

The antifungal drug itraconazole inhibits angiogenesis and Hedgehog signaling and delays tumor growth in murine prostate cancer xenograft models. We conducted a noncomparative, randomized, phase II study evaluating the antitumor efficacy of two doses of oral itraconazole in men with metastatic prostate cancer.

PATIENTS AND METHODS

We randomly assigned 46 men with chemotherapy-naïve metastatic castration-resistant prostate cancer (CRPC) to receive low-dose (200 mg/day) or high-dose (600 mg/day) itraconazole until disease progression or unacceptable toxicity. The primary endpoint was the prostate-specific antigen (PSA) progression-free survival (PPFS) rate at 24 weeks; a 45% success rate in either arm was prespecified as constituting clinical significance. Secondary endpoints included the progression-free survival (PFS) rate and PSA response rate (Prostate Cancer Working Group criteria). Exploratory outcomes included circulating tumor cell (CTC) enumeration, serum androgen measurements, as well as pharmacokinetic and pharmacodynamic analyses.

RESULTS

The high-dose arm enrolled to completion (n = 29), but the low-dose arm closed early (n = 17) because of a prespecified futility rule. The PPFS rates at 24 weeks were 11.8% in the low-dose arm and 48.0% in the high-dose arm. The median PFS times were 11.9 weeks and 35.9 weeks, respectively. PSA response rates were 0% and 14.3%, respectively. In addition, itraconazole had favorable effects on CTC counts, and it suppressed Hedgehog signaling in skin biopsy samples. Itraconazole did not reduce serum testosterone or dehydroepiandrostenedione sulfate levels. Common toxicities included fatigue, nausea, anorexia, rash, and a syndrome of hypokalemia, hypertension, and edema.

CONCLUSION

High-dose itraconazole (600 mg/day) has modest antitumor activity in men with metastatic CRPC that is not mediated by testosterone suppression.

An immunohistochemical signature comprising PTEN, MYC, and Ki67 predicts progression in prostate cancer patients receiving adjuvant docetaxel after prostatectomy

BACKGROUND

Loss of the tumor suppressor PTEN is common in prostate cancer and may have prognostic significance. The authors examined PTEN and additional protein markers in primary tumors from patients with high-risk, localized prostate cancer who received adjuvant docetaxel in a prospective multicenter trial (TAX2501).

METHODS

Fifty-six of 77 patients enrolled in TAX2501 had primary prostatectomy specimens available for immunohistochemical analysis of PTEN, MYC, ERG, tumor protein p53 (p53), antigen KI-67 (Ki67), and phosphorylated forms of Akt, mammalian target of rapamycin (mTOR), and S6 ribosomal protein. Protocol-defined progression included a prostate-specific antigen (PSA) level ≥ 0.4 ng/mL, radiologic/clinical recurrence, or death. Univariate and multivariable proportional hazards regression analyses were used to investigate the influence of PTEN status (and other protein markers) on progression-free survival (PFS).

RESULTS

In this exploratory, post hoc analysis, PTEN protein loss (vs presence) was observed in 61% of patients and was associated with lower preoperative PSA levels, higher clinical stage, lower Ki67 expression, the presence of p53, and the presence of ERG. In univariate analysis, the factors associated with PFS included Gleason sum, seminal vesicle invasion, PTEN status, MYC expression, and Ki67 expression. In multivariable analysis, only 3 variables emerged as independent prognostic factors for PFS: PTEN status (P = .035), MYC expression (P = .001), and Ki67 expression (P < .001). A prognostic model was constructed that incorporated clinical covariates as well as information on PTEN, MYC, and Ki67.

CONCLUSIONS

The current results indicated that PTEN status, MYC expression, and Ki67 expression in primary tumor samples may predict PFS more accurately than clinical factors alone in men with high-risk prostate cancer who receive adjuvant docetaxel after prostatectomy. If validated, these hypothesis-generating findings may have prognostic and therapeutic implications and may aid clinical trial design.

Removing barriers to participation in clinical trials, a conceptual framework and retrospective chart review study

BACKGROUND

Enrollment in interventional therapeutic clinical trials is a small fraction of all patients who might participate given reasonable access.

METHODS

A hierarchical approach is utilized in measuring staged participation from trial availability to patient enrollment. Our framework suggests that concern for justice comes in the design and eligibility criteria for clinical trials; attention to beneficence is given in the eligibility and physician triage stages. The remaining four stages rely on respect for persons. An example is given where reasons for nonparticipation or barriers to participation in prostate cancer clinical trials are examined within the framework. In addition, medical oncology patients with an initial six month consultation are tracked from one stage to the next by race using the framework to assess participation comparability.

RESULTS

We illustrated seven transitions from being a patient to enrollment in a clinical trial in a small study of prostate cancer cases who consulted SKCCC Medical Oncology Department in early 2010. Pilot data suggest transition probabilities as follows: 65% availability, 84% eligibility, 92% patient triage, 89% trials discussed, 45% patient interested, 63% patient consented, and 92% patient enrolled. The average transition probability was 77.7%. The average transition probability, patient-trial-fit was 50%; opportunity was 51%, and acceptance was 66.7%. Trial availability, patient interest and patient consented were three transitions that were below the average; none were statistically significant.

CONCLUSIONS

The framework may serve to streamline comprehensive reporting of clinical trial participation to the benefit of patients and the ethical conduct of clinical trials.

A phase I/IIA study of AGS-PSCA for castration-resistant prostate cancer

BACKGROUND

This first-in-human phase I/IIA study was designed to evaluate the safety and pharmacokinetics (PKs) of AGS-PSCA a fully human monoclonal antibody directed to prostate stem cell antigen (PSCA) in progressive castration-resistant prostate cancer.

PATIENTS AND METHODS

Twenty-nine patients were administered infusions of AGS-PSCA (1-40 mg/kg) every 3 weeks for 12 weeks; 18 final patients received a 40-mg/kg loading dose followed by 20-mg/kg repeat doses. Primary end points were safety and PK. Immunogenicity, antitumor activity and circulating tumor cells were also evaluated.

RESULTS

No drug-related serious adverse events were noted. Dose escalation stopped before reaching the maximum tolerated dose as target concentrations were achieved. Drug levels accumulated linearly with dose and the mean terminal half-life was 2-3 weeks across dose levels. The 40-mg/kg loading dose followed by repeated 20-mg/kg doses yielded serum drug concentrations above the projected minimum therapeutic threshold after two to three doses without excessive drug accumulation or toxicity. Significant antitumor effects were not seen.

CONCLUSIONS

A 40-mg/kg loading dose followed by 20-mg/kg infusions every 3 weeks is the recommended phase II dose of AGS-PSCA. PSCA is a promising drug target and studies in prostate and other relevant solid tumors are planned.

Management of bone metastases in refractory prostate cancer--role of denosumab

This article reviews the problem of bone disease in prostate cancer and the evolving role of the novel agent denosumab, a fully human monoclonal antibody that inhibits the receptor activator of nuclear factor-κB ligand, in suppressing bone resorption and offering bone protection in this disease. Prostate cancer frequently metastasizes to bone, and additionally its treatment with androgen deprivation leads to accelerated bone loss resulting in clinically relevant skeletal complications associated with disabling symptoms. Among the bone-targeting therapeutic strategies investigated for the prevention of bone complications, the potent bisphosphonate zoledronic acid has been the most widely used agent for bone protection in the past decade. Denosumab is the first among a new class of osteoclast-targeting agents to show superior efficacy in several clinical scenarios in both prostate and breast cancer, as well as in osteoporosis, but the focus of this review will be on its role in prostate cancer. The safety and efficacy of denosumab versus zoledronic acid was established in a randomized trial, demonstrating a delay in skeletal-related events in metastatic castration-resistant prostate cancer patients. This study led to the approval of denosumab in the US. The chief risks of denosumab were hypocalcemia and osteonecrosis of the jaw. Denosumab was also approved for fracture risk reduction in patients on androgen-deprivation therapy for nonmetastatic prostate cancer. Although denosumab extended bone metastasis-free survival in a Phase III trial in men with castration-resistant nonmetastatic prostate cancer to a statistically significant degree, a Food and Drug Administration committee found that the effect was not sufficiently clinically meaningful for regulatory approval, and the Food and Drug Administration issued a letter concurring with the committee's recommendation. The role of denosumab in prostate cancer will continue to evolve either as monotherapy or in combination with other bone-targeting strategies.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Phase I study of enzastaurin and bevacizumab in patients with advanced cancer: safety, efficacy and pharmacokinetics

Purpose Given distinct mechanism of actions of enzastaurin and bevacizumab, preclinical studies suggest enhanced antitumor activity in combination. This phase I study assessed the combination’s safety and efficacy. Patients and methods Six advanced cancer patients could be enrolled in each of 11 cohorts. Patients received an enzastaurin loading dose. Oral enzastaurin (500 mg once daily [QD], 250 mg twice daily [BID], 375 mg BID, 500 mg BID, and 750 mg BID) was escalated in each cohort in combination with bevacizumab dosed at 5 mg/kg every 2 weeks, 10 mg/kg every 2 weeks, or 15 mg/kg every 3 weeks until a dose-limiting toxicity (DLT) occurred in 2 of 6 patients in any cohort. Results Sixty-seven patients (31, ovarian cancer [ovcar]) were evaluable for safety and efficacy. Six treatment-related DLTs occurred: grade 3 fatigue (n = 4), grade 4 cerebral hemorrhage, and grade 3 elevated aspartate transaminase. Common drug-related toxicities included change in color of urine and stool, fatigue, pain, diarrhea, and nausea. The maximum tolerated dose of enzastaurin was 750 mg BID in combination with any tested bevacizumab dose/schedule. Overall response rate was 19.4 % (32.3 % ovcar). Median time to progression was 3.7 months (95 % confidence interval [CI], 2.7–5.5), with 8.3 months (95 % CI, 3.7–11.1) in ovcar. Overall, 35.9 % (50.4 % ovcar) of patients remained without disease progression after 6 months. Conclusion The recommended phase II doses of enzastaurin were 500 mg QD up to 500 mg BID with any tested dose/schedule of bevacizumab. This combination demonstrated encouraging clinical activity, particularly in ovcar.

Engineering a prostate-specific membrane antigen-activated tumor endothelial cell prodrug for cancer therapy

Heterogeneous expression of drug target proteins within tumor sites is a major mechanism of resistance to anticancer therapies. We describe a strategy to selectively inhibit, within tumor sites, the function of a critical intracellular protein, the sarcoplasmic/endoplasmic reticulum calcium adenosine triphosphatase (SERCA) pump, whose proper function is required by all cell types for viability. To achieve targeted inhibition, we took advantage of the unique expression of the carboxypeptidase prostate-specific membrane antigen (PSMA) by tumor endothelial cells within the microenvironment of solid tumors. We generated a prodrug, G202, consisting of a PSMA-specific peptide coupled to an analog of the potent SERCA pump inhibitor thapsigargin. G202 produced substantial tumor regression against a panel of human cancer xenografts in vivo at doses that were minimally toxic to the host. On the basis of these data, a phase 1 dose-escalation clinical trial has been initiated with G202 in patients with advanced cancer.

The effect of clinical trial participation versus non-participation on overall survival in men receiving first-line docetaxel-containing chemotherapy for metastatic castration-resistant prostate cancer

What's known on the subject? and What does the study add? Previous studies have reported better outcomes in cancer patients that enrolled in clinical trials, suggesting that trial participation in itself might be beneficial. We investigated the potential positive effect of clinical trial participation on survival outcomes of patients with metastatic castration-resistant prostate cancer who were treated with first-line docetaxel-containing chemotherapy. After accounting for potential baseline inequalities, participation in a clinical trial itself was associated with significantly longer overall survival in these patients.

OBJECTIVE

• To study differences in baseline characteristics and outcomes of patients with metastatic castration-resistant prostate cancer (mCRPC) receiving first-line docetaxel-containing chemotherapy on prospective clinical studies (trial participants) versus those receiving this therapy outside of a clinical study (non-participants).

PATIENTS AND METHODS

• Records from 247 consecutive chemotherapy-naive patients who were treated with docetaxel-containing chemotherapy for mCRPC at a single high-volume centre from 1998 to 2010 were reviewed. • All patients received docetaxel either as clinical trial participants (n= 142; 11 separate studies) or as non-participants (n= 105). • Univariable and multivariable Cox regression models predicted overall survival after chemotherapy initiation.

RESULTS

• There was no significant difference between trial participation and non-participation with respect to patient age, type of primary treatment, tumour grade or clinical stage. • Multivariable analyses showed a significantly lower risk of all-cause mortality (hazard ratio 0.567; P= 0.027) among trial participants vs non-participants.

CONCLUSIONS

• Patients that were treated with docetaxel for mCRPC showed a significantly longer overall survival when enrolled in a clinical trial. • Improved survival in trial participants may reflect the better medical oversight typically seen in patients enrolled in trials, more regimented follow-up schedules, or a positive effect on caregivers' attitudes because of greater contact with medical services. • With the retrospective nature of this analysis and the small study population, prospective studies are needed to validate the present findings and to further investigate the relationship between clinical trial participation and outcomes.

What can I do? Recommendations for responding to issues identified by patient-reported outcomes assessments used in clinical practice

There is increased interest in using patient-reported outcome (PRO) measures in routine clinical practice to improve patient management. The effectiveness of this intervention may be facilitated by providing suggestions to clinicians on how to address issues identified by the PROs. We sought to develop recommendations for clinicians on how to respond to issues covered by common cancer PRO questionnaires, including functional problems (eg, physical, social, emotional), symptoms (eg, diarrhea, pain), and needs (eg, patient care and support, information). The recommendations would be incorporated into a Web-based system for PRO assessment and reporting in use at our large, academic cancer center. To develop the recommendations, we conducted a multiphase, multidisciplinary, consensus process. We reviewed the literature and conducted one-on-one interviews with experts from various disciplines. Experts included medical oncologists, radiation oncologists, nurses, an internist, a palliative care specialist, an outcomes researcher, a chaplain, a social worker, and patient advocates. These interviews elicited the experts' recommendations for addressing problems in common PRO domains. Finally, we held a panel meeting attended by all the experts to attain consensus on the recommendations. The final consensus suggestions recommend further assessment of the problem as a first step. Treatment suggestions range from medication adjustments to lifestyle modifications to referrals to other disciplines. Further research will test whether clinicians find these suggestions useful for patient management.