Chemotherapy with mitoxantrone plus prednisone or prednisone alone for symptomatic hormone-resistant prostate cancer: a Canadian randomized trial with palliative end points

The transcription factor ZEB1 promotes chemoresistance in prostate cancer cell lines

One of the factors promoting tumoral progress is the abnormal activation of the epithelial–mesenchymal transition (EMT) program which has been associated with chemoresistance in tumoral cells. The transcription factor zinc finger E-box-binding homeobox 1 (ZEB1), a key EMT activator, has recently been related to docetaxel resistance, the main chemotherapeutic used in advanced prostate cancer treatment. The mechanisms involved in this protective effect are still unclear. In a previous work, we demonstrated that ZEB1 expression induced an EMT-like phenotype in prostate cancer cell lines. In this work, we used prostate cancer cell lines 22Rv1 and DU145 to study the effect of ZEB1 modulation on docetaxel resistance and its possible mechanisms. The results showed that ZEB1 overexpression conferred to 22Rv1 cell resistance to docetaxel while its silencing made DU145 cells more sensitive to it. Analysis of resistance markers showed no presence of ATP-binding cassette subfamily B member 1 (MDR1) and no changes in breast cancer resistance protein (BCRP) or ATP-binding cassette subfamily C member 10 (MRP7). However, a correlation between ZEB1, multidrug resistance-associated protein 1 (MRP1), and ATP-binding cassette subfamily C member 4 (MRP4) expression was observed. MRP4 inhibition, using MK571, resensitized cells with ZEB1 overexpression to docetaxel treatment. In addition, modulation of ZEB1 and subsequent change in MRP4 expression correlated with a lower apoptotic response to docetaxel, characterized by lower B-cell lymphoma 2 (Bcl2), high BCL2-associated X protein (Bax), and high active caspase 3 expression. The response to docetaxel in our model seems to be mediated mainly by activation of the apoptotic death program. Our results showed that modulation of MRP4 could be a mediator of ZEB1-related resistance to docetaxel in prostate cancer, making it a possible marker for chemotherapy response in patients who do not express MDR1.

Renal and Cardiovascular Toxicities by New Systemic Treatments for Prostate Cancer

Prostate cancer (PC) is the most common male cancer in Western Countries. In recent years, the treatment of relapsed or metastatic disease had benefited by the introduction of a variety of new different drugs. In consideration of the relative long survival of PC patients, side effects of these drugs must be considered and monitored. In this review, we analyzed the newly developed therapies for PC treatment, describing the mechanism of action, the metabolism and latest clinical trials that led to the approval of these drugs in clinical practice. We then evaluated the cardiovascular and renal side effects from pivotal phase III and II studies and meta-analyses. Cardiovascular side effects are the most frequent, in particular hypertension, while renal toxicity is rarer and not well described in literature. Therefore, there is a need to better define the effects of these therapies, in order to personalize patient treatment on the basis of their comorbidities and preferences, in addition to their symptoms and disease load.

Clinical Benefit in the Treatment of Patients with Early Breast Cancer

Adjuvant treatment for early breast cancer involves multiple modalities with distinct toxicities and varying relative contributions to the improvement of long-term outcomes. In many situations the expected benefits of treatment may be modest and thus debated, and even in higher risk scenarios, when treatment is clearly indicated, several options are available with varying schedules and toxicities. Regulatory and professional society guidelines defining clinical benefit are available to guide decision-making, but do not capture clinical meaningfulness. There is wide variation among patients regarding the expected improvement in outcomes sufficient to make adjuvant chemotherapy or endocrine therapy worthwhile. While many consider small improvements in outcomes meaningful, some need greater benefit, and a small minority prefer to avoid adjuvant therapies at any rate. Shared decision making has a central role in bridging between clinical evidence, multiple treatment alternatives and patient preferences in the adjuvant treatment of early breast cancer. It is associated with increased patient involvement and responsibility, satisfaction, quality of life and in some instances increase the likelihood of accepting adjuvant treatment. A current understanding of evidence and clinical guidelines, combined with the skills to elicit and appreciate individual patient preferences, is necessary to determine an optimal treatment approach for every individual with breast cancer.

Influence of short-term dexamethasone on the efficacy of 177 Lu-PSMA-617 in patients with metastatic castration-resistant prostate cancer

BACKGROUND AND AIM

Corticosteroids alone or in combination therapy are associated with favorable biochemical responses in metastatic castration-resistant prostate cancer (mCRPC). We speculated that the intermittent addition of dexamethasone may also enhance the antitumor effect of radioligand therapy (RLT) with ¹⁷⁷ Lu-prostate-specific membrane antigen (PSMA)-617.

PATIENTS AND METHODS

Seventy-one patients with mCRPC were treated with 1 to 5 cycles of ¹⁷⁷ Lu-PSMA-617 (6.0-7.4 GBq per cycle) at 6 to 8 weeks intervals. Based on the clinical decision (eg, in the case of vertebral metastases), 56% of patients received 4 mg of dexamethasone for the first 5 days of each cycle. Biochemical response rates, PSA decline and progression-free survival (PFS) were analyzed after one, three, and five cycles of RLT.

RESULTS

PSA response rates were not significantly different between patients receiving ¹⁷⁷ Lu-PSMA-617 plus dexamethasone and those receiving ¹⁷⁷ Lu-PSMA-617 alone after one, three, and five cycles (33% vs 39%, P = .62; 45% vs 45%, P = 1.0; and 38% vs 42%, P = .81). However, there was a nonsignificant trend for a more pronounced PSA decline in patients with bone metastases receiving adjunct dexamethasone (-21% ± 50% vs +11% ± 90%, P = .08; -21% ± 69% vs +22% ± 116%, P = .07; -13% ± 76% vs +32% ± 119%, P = .07). Median PFS tended to be longer in patients with bone metastases receiving ¹⁷⁷ Lu-PSMA-617 plus dexamethasone (146 vs 81 days; hazard ratio: 0.87 [95% confidence interval: 0.47-1.61]; P = .20). Multiple regression analysis showed that age (P = .0110), alkaline phosphatase levels (P = .0380) and adjunct dexamethasone (P = .0285) were independent predictors of changes in PSA in patients with bone metastases.

CONCLUSIONS

We observed high response rates to ¹⁷⁷ Lu-PSMA-617 RLT in men with mCRPC. The short-term addition of dexamethasone to ¹⁷⁷ Lu-PSMA-617 had no striking antitumor effect but might enhance biochemical responses in patients with bone metastases. Future trials are warranted to test this hypothesis in a prospective setting.

Integration of Patient Reported Outcomes in Drug Development in Genitourinary Cancers

PURPOSE OF REVIEW

Patient reported outcomes (PROs) are increasingly utilized in cancer drug development, and are of particular importance in genitourinary cancers due to symptom burden, multiple treatment options with similar efficacy, and often prolonged duration of disease. Here we review current data and perspectives related to use of PROs in drug development for genitourinary cancers, including insights on the regulatory process for drug approval.

RECENT FINDINGS

The FDA is committed to incorporating PRO data into the regulatory process for development and approval of new cancer drugs, but challenges exist due to lack of standardization of PRO instrument choice and analytic approach, missing data, and difficulty isolating treatment effect from disease-related effects. We review guidance for standardization of PRO methodology that is nonetheless tailored to disease state and anticipated effects of treatment. PRO and efficacy data should be simultaneously analyzed and reported for best clinical practice. Multiple disease-specific PRO instruments exist for genitourinary cancers. While clinicians, researchers, and regulatory bodies alike recognize the importance of PROs in cancer drug development, challenges remain regarding implementation of best practices.

Ra-223 Treatment for Bone Metastases in Castrate-Resistant Prostate Cancer: Practical Management Issues for Patient Selection

Bone metastases are common in men with metastatic castrate-resistant prostate cancer (mCRPC), occurring in 30% of patients within 2 years of castrate resistance and in >90% of patients over the disease course. There are 6 US Food and Drug Administration-approved therapies for mCRPC with demonstrated survival benefit. Of these, only radium-223 (Ra-223) specifically targets bone metastases, delays development of skeletal-related events, and improves survival. This review discusses key data from the ALSYMPCA trial, which contributed to the approval of Ra-223. Data from other trials are highlighted to provide further insight into which patients might benefit from Ra-223. Special patient populations are described, as well as other considerations for the administration of Ra-223. Finally, ongoing trials of Ra-223 combined with other therapies for mCRPC are discussed. These include combining Ra-223 with sipuleucel-T or immunooncology agents, to enhance immune responses, and trials in mildly symptomatic or asymptomatic patients. To date, the optimal timing, sequence, and combinations of Ra-223 with other agents are yet to be determined. The goals of this review are to provide insight into practical aspects of patient selection for Ra-223 treatment and to discuss key therapeutic strategies using the 6 approved mCRPC agents in patients with bone metastases. Results from ongoing trials should help guide the practitioner in using Ra-223 in patients with mCRPC.

Treatment of Advanced Prostate Cancer

The therapeutic landscape of prostate cancer has been transformed over the last decade by new therapeutics, advanced functional imaging, next-generation sequencing, and better use of existing therapies in early-stage disease. Until 2004, progression on androgen deprivation therapy for metastatic disease was treated with the addition of secondary hormonal manipulation; in the last decade, six systemic agents have been approved for the treatment of castration-resistant prostate cancer. We review clinical trials and survival benefit for these therapies and assess how the understanding of the disease shifted as these therapies were developed. We also discuss advances in noncastrate disease states, identification of biomarkers for prognosis and treatment selection, and opportunities in locoregional therapy to delay androgen deprivation therapy.

Optical detection of the structural properties of tumor tissue generated by xenografting of drug-sensitive and drug-resistant cancer cells using partial wave spectroscopy (PWS)

A mesoscopic physics-based optical imaging technique, partial wave spectroscopy (PWS), has been used for the detection of cancer by probing nanoscale structural alterations in cells/tissue. The development of drug-resistant cancer cells/tissues during chemotherapy is a major challenge in cancer treatment. In this paper, using a mouse model and PWS, the structural properties of tumor tissue grown in 3D structures by xenografting drug-resistant and drug-sensitive human prostate cancer cells having 2D structures, are studied. The results show that the 3D xenografted tissues maintain a similar hierarchy of the degree of structural disorder properties as that of the 2D original drug-sensitive and drug-resistant cells.

Reciprocal and Autonomous Glucocorticoid and Androgen Receptor Activation in Salivary Duct Carcinoma

PURPOSE

To determine the expression of glucocorticoid receptor (GR) and androgen receptor (AR) in salivary duct carcinoma (SDC) and to analyze the role of these proteins in the development and management of this disease entity.

EXPERIMENTAL DESIGN

We performed a phenotypic assessment of GR and AR localization and expression, and determined their association with clinicopathologic factors in 67 primary SDCs. In vitro functional and response analysis of SDC cell lines was also performed.

RESULTS

Of the 67 primary tumors, 12 (18%) overexpressed GR protein, 30 (45%) had constitutive expression, and 25 (37%) had complete loss of expression. Reciprocal GR and AR expression was found in 32 (48%) tumors, concurrent constitutive GR and AR expression in 23 (34%), and simultaneous loss of both receptors and high GR with AR expressions were found in 12 (18%). GR overexpression was significantly associated with worse clinical outcomes. In vitro ligand-independent AR activation was observed in both male- and female-derived cell lines. GR antagonist treatment resulted in decreased cell proliferation and survival in GR-overexpressing cells, irrespective of AR status. Reciprocal GR- and AR-knockdown experiments revealed an independent interaction.

CONCLUSIONS

Our study, for the first time, demonstrates differential GR and AR expressions, autonomous GR and AR activation, and ligand-independent AR expression and activation in SDC cells. The findings provide critical information on the roles of GR and AR steroid receptors in SDC tumorigenesis and development of biomarkers to guide targeted steroid receptor therapy trials in patients with these tumors.

Insights into the success and failure of systemic therapy for hepatocellular carcinoma

Systemic treatment for hepatocellular carcinoma (HCC) has been boosted by the incorporation of new agents after many negative phase III trials in the decade since the approval of sorafenib. Sorafenib introduced the concept that targeting specific hallmarks of hepatocarcinogenesis could modify the dismal prognosis of this disease, with the drug remaining a cornerstone in the upfront therapy for advanced HCC. The design of clinical trials in this malignancy is complicated by important obstacles related to patient selection, prognostic assessment and the need for endpoints that correlate with improvement in survival outcomes. In addition, the currently used criteria to determine treatment response or progression might prevent physicians from making appropriate clinical judgements and interpreting evidence arising from trials. In this Review, we discuss the advances in systemic therapy for HCC and critically review trial designs in HCC. Although novel therapies, such as new targeted agents and immunotherapies, are being rapidly incorporated, it is paramount to design future clinical trials based on the lessons learned from past failures and successes.

Survival Outcomes From a Cumulative Analysis of Worldwide Observational Studies on Sequential Use of New Agents in Metastatic Castration-Resistant Prostate Cancer

INTRODUCTION

The sequential use of a number of new agents (NAs) have improved the overall survival (OS) of patients with metastatic castration-resistant prostate cancer whose disease progresses after docetaxel (DOC) treatment. The aim of this study was to assess the cumulative survival outcomes of different sequencing strategies by evaluating the individual data from published studies of patients treated with a post-DOC treatment sequence of 2 NAs.

PATIENTS AND METHODS

The patients' individual data were analyzed to investigate whether different sequencing strategies lead to differences in OS.

RESULTS

We analyzed the data of 1099 evaluable patients. Among the patients treated with a second-line new hormone agent (NHA), median OS from the start of third-line treatment was significantly longer in the patients treated with cabazitaxel (CABA) than in those treated with abiraterone acetate or enzalutamide. Median cumulative OS (cumOS) from the start of second-line treatment was 21.1 months in the patients who received NHA then NHA, 22.1 months in those who received NHA then CABA, and 21.0 months in those who received CABA then NHA. Among the patients with a second-line progression-free survival of ≥6 months, median cumOS was significantly longer in patients who received CABA-including sequences than in those treated with NHA then NHA sequences (29.5 vs. 24.8 months; P = .03).

CONCLUSION

Our findings suggest that the sequential use of NAs with different mechanisms of action improves cumOS regardless of the order in which they are administered, thus supporting the hypothesis of cross-resistance between the 2 NHAs.

Dandelion Root and Lemongrass Extracts Induce Apoptosis, Enhance Chemotherapeutic Efficacy, and Reduce Tumour Xenograft Growth In Vivo in Prostate Cancer

Many conventional chemotherapies have indicated side effects due to a lack of treatment specificity and are thus not suitable for long-term usage. Natural health products are well-tolerated and safe for consumption, and some have pharmaceutical uses particularly for their anticancer effects. We have previously reported the anticancer efficacy of dandelion (Taraxacum officinale) root and lemongrass (Cymbopogon citratus) extracts. However, their efficacy on prostate cancer and their interactions with standard chemotherapeutics have not been studied to determine if they will be suitable for adjuvant therapies. If successful, these extracts could potentially be used in conjunction with chemotherapeutics to minimize the risk of drug-related toxicity and enhance the efficacy of the treatment. We have demonstrated that both dandelion root extract (DRE) and lemongrass extract (LGE) exhibit selective anticancer activity. Importantly, DRE and LGE addition to the chemotherapeutics taxol and mitoxantrone was determined to enhance the induction of apoptosis when compared to individual chemotherapy treatment alone. Further, DRE and LGE were able to significantly reduce the tumour burden in prostate cancer xenograft models when administered orally, while also being well-tolerated. Thus, the implementation of these well-tolerated extracts in adjuvant therapies could be a selective and efficacious approach to prostate cancer treatment.

Cabozantinib Versus Mitoxantrone-prednisone in Symptomatic Metastatic Castration-resistant Prostate Cancer: A Randomized Phase 3 Trial with a Primary Pain Endpoint

BACKGROUND

Bone metastases in patients with metastatic castration-resistant prostate cancer (mCRPC) are associated with debilitating pain and functional compromise.

OBJECTIVE

To compare pain palliation as the primary endpoint for cabozantinib versus mitoxantrone-prednisone in men with mCRPC and symptomatic bone metastases using patient-reported outcome measures.

DESIGN, SETTING, AND PARTICIPANTS

A randomized, double-blind phase 3 trial (COMET-2; NCT01522443) in men with mCRPC and narcotic-dependent pain from bone metastases who had progressed after treatment with docetaxel and either abiraterone or enzalutamide.

INTERVENTION

Cabozantinib 60mg once daily orally versus mitoxantrone 12mg/m2 every 3wk plus prednisone 5mg twice daily orally.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The primary endpoint was pain response at week 6 confirmed at week 12 (≥30% decrease from baseline in patient-reported average daily worst pain score via the Brief Pain Inventory without increased narcotic use). The planned sample size was 246 to achieve ≥90% power.

RESULTS AND LIMITATIONS

Enrollment was terminated early because cabozantinib did not demonstrate a survival benefit in the companion COMET-1 trial. At study closure, 119 participants were randomized (cabozantinib: N=61; mitoxantrone-prednisone: N=58). Complete pain and narcotic use data were available at baseline, week 6, and week 12 for 73/106 (69%) patients. There was no significant difference in the pain response with cabozantinib versus mitoxantrone-prednisone: the proportions of responders were 15% versus 17%, a -2% difference (95% confidence interval: -16% to 11%, p=0.8). Barriers to accrual included pretreatment requirements for a washout period of prior anticancer therapy and a narcotic optimization period to maximize analgesic dosing.

CONCLUSIONS

Cabozantinib treatment did not demonstrate better pain palliation than mitoxantrone-prednisone in heavily pretreated patients with mCRPC and symptomatic bone metastases. Future pain-palliation trials should incorporate briefer timelines from enrollment to treatment initiation.

PATIENT SUMMARY

Cabozantinib was not better than mitoxantrone-prednisone for pain relief in patients with castration-resistant prostate cancer and debilitating pain from bone metastases.

Inter- and intra-patient variability in pharmacokinetics of abiraterone acetate in metastatic prostate cancer

PURPOSE

This study examined the inter- and intra-patient variability in pharmacokinetics of AA and its metabolites abiraterone and Δ(4)-abiraterone (D4A), and potential contributing factors.

METHODS

AA administered daily for ≥4 weeks concurrently with androgen deprivation therapy (ADT) for mCRPC were included. Pharmacokinetic evaluation was performed at two consecutive visits at least 4 weeks apart. Plasma samples were collected 24 h after last dose of AA to obtain drug trough level (DTL) of two active metabolites, abiraterone and D4A.

RESULTS

39 plasma samples were obtained from 22 patients, with 17 patients had repeat DTL measurement. Considerable inter-patient variability in DTL was seen, with initial DTL for abiraterone ranging between 1.5 and 25.4 ng/ml (CV 61%) and for D4A between 0.2 and 2.5 ng/ml (CV 61%). Intra-patient variability in DTL for abiraterone varied between 0.85 and 336% and for D4A between 1.14 and 199%. There was no increase in AA exposure with use of dexamethasone (n = 5; DTL 13.9) compared with prednisone (n = 17; DTL 11.0 p = 0.5), dosing in fasted state (n = 13, DTL 12.1) compared to dosing in fed state (n = 9; DTL 11.1, p = 0.8), or chemotherapy-exposed (n = 10; DTL 8.9) compared to chemotherapy naïve (n = 12; DTL 14.0, p = 0.1).

CONCLUSIONS

Our cohort demonstrated high inter- and intra-patient variability in both abiraterone and D4A with fixed dosing of AA, with no effect from choice of corticosteroids, prior use of chemotherapy, or dosing in fasting state. Monitoring DTL of AA may be necessary to minimise risk of patients being under-dosed and earlier development of resistance.

The evolution and understanding of skeletal complication endpoints in clinical trials of tumors with metastasis to the bone

Bone metastases are a frequent complication of solid tumors, leading to significant skeletal sequelae that negatively impact quality of life and survival. Prevention and management of skeletal-related complications are critical treatment goals in oncology. Endpoints used in clinical trials to evaluate skeletal-related complications have evolved. In contrast to single measures of bone health, contemporary clinical trial endpoints reflect composite measures of skeletal-related complications, and increasingly also survival. In addition, key symptomatic components, which are more reflective of quality of life and the patient experience, are being incorporated. Given the evolution and resulting diversity of the endpoints being used in pivotal trials, it is becoming increasingly relevant to clarify the utility and the potential clinical impact of these measures not only within the context of trials but also in the real-world setting. Here, we describe the development and evolution of skeletal endpoints used in trials, and discuss their clinical relevance.

Pantoprazole Affecting Docetaxel Resistance Pathways via Autophagy (PANDORA): Phase II Trial of High Dose Pantoprazole (Autophagy Inhibitor) with Docetaxel in Metastatic Castration-Resistant Prostate Cancer (mCRPC)

BACKGROUND

Enhancing the effectiveness of docetaxel for men with metastatic castration-resistant prostate cancer (mCRPC) is an unmet clinical need. Preclinical studies demonstrated that high-dose pantoprazole can prevent or delay resistance to docetaxel via the inhibition of autophagy in several solid tumor xenografts.

MATERIALS AND METHODS

Men with chemotherapy-naive mCRPC with a prostate-specific antigen (PSA) >10 ng/mL were eligible for enrolment. Men received intravenous pantoprazole (240 mg) prior to docetaxel (75 mg/m²) every 21 days, with continuous prednisone 5 mg twice daily. Primary endpoint was a confirmed ≥50% decline of PSA. The trial used a Simon's two-stage design.

RESULTS

Between November 2012 and March 2015, 21 men with a median age of 70 years (range, 58-81) were treated (median, 6 cycles; range, 2-11). Men had received prior systemic therapies (median, 1; range, 0-3), and 14 had received abiraterone and/or enzalutamide. PSA response rate was 52% (11/21), which did not meet the prespecified criterion (≥13/21 responders) to proceed to stage 2 of the study. At interim analysis with a median follow-up of 17 months, 18 (86%) men were deceased (15 castration-resistant prostate cancer, 2 unknown, 1 radiation complication). Of the men with RECIST measurable disease, the radiographic partial response rate was 31% (4/13). The estimated median overall survival was 15.7 months (95% confidence interval [CI], 9.3-19.6) and median PFS was 5.3 months (95% CI, 2.6-12.9). There were no toxic deaths, and all adverse events were attributed to docetaxel.

CONCLUSION

The combination of docetaxel and pantoprazole was tolerable, but the resultant clinical activity was not sufficient to meet the ambitious predefined target to warrant further testing.

IMPLICATIONS FOR PRACTICE

To date, no docetaxel combination regimen has reported superior efficacy over docetaxel alone in men with metastatic castration-resistant prostate cancer (mCRPC). The PANDORA trial has demonstrated that the combination of high dose pantoprazole with docetaxel is tolerable, but the clinical activity was not sufficient to warrant further testing. The chemotherapy standard of care for men with mCRPC remains docetaxel with prednisone. Future studies of autophagy inhibitors will need to measure autophagy inhibition accurately and determine the degree of autophagy inhibition required to produce a meaningful clinical response.

Activity and safety of metronomic cyclophosphamide in the modern era of metastatic castration-resistant prostate cancer

Aim: To evaluate activity of metronomic cyclophosphamide (mCTX) in heavily pretreated metastatic castration-resistant prostate cancer (mCRPC) patients. Patients & methods: We retrospectively evaluated a consecutive series of 74 mCRPC patients treated with at least one new agent after docetaxel failure, who received once-daily oral mCTX treatment at a fixed dose of 50 mg. Results: The treatment was well tolerated. Sixteen percent of the patients experienced a major biochemical response. Median progression-free survival was 4.0 months, and median overall survival was 8.1 months. Conclusions: In the modern context of mCRPC, mCTX may represent a valuable and inexpensive alternative to new agents, which have shown similar activity in heavily pretreated patients.

Combination of cabazitaxel and p53 gene therapy abolishes prostate carcinoma tumor growth

For patients with metastatic prostate cancer, the 5-year survival rate of 31% points to a need for novel therapies and improvement of existing modalities. We propose that p53 gene therapy and chemotherapy, when combined, will provide superior tumor cell killing for the treatment of prostate carcinoma. To this end, we have developed the AdRGD-PGp53 vector which offers autoregulated expression of p53, resulting in enhanced tumor cell killing in vitro and in vivo. Here, we combined AdRGD-PGp53 along with the chemotherapy drugs used in the clinical treatment of prostate carcinoma, mitoxantrone, docetaxel, or cabazitaxel. Our results indicate that all drugs increase phosphorylation of p53, leading to improved induction of p53 targets. In vitro experiments reveal that AdRGD-PGp53 sensitizes prostate cancer cells to each of the drugs tested, conferring increased levels of cell death. In a xenograft mouse model of in situ gene therapy, AdRGD-PGp53 treatment, when combined with cabazitaxel, drastically reduced tumor progression and increased survival rates to 100%. Strikingly, we used a sub-therapeutic dose of cabazitaxel thus avoiding leukopenia, yet still showed potent anti-tumor effects when combined with AdRGD-PGp53 in this mouse model. The AdRGD-PGp53 approach warrants further development for its application in gene therapy of prostate carcinoma.

Effectiveness of Platinum-Based Chemotherapy in Patients With Metastatic Prostate Cancer: Systematic Review and Meta-analysis

BACKGROUND

Taxanes are the only cytotoxic drugs that have demonstrated a survival benefit for patients with castration-resistant prostate cancer (CRPC), but there is some evidence that platinum compounds may also benefit such patients.

METHODS

We performed a systematic search on electronic databases. We sought prospective clinical studies testing platinum compounds for CRPC. Platinum compounds could be delivered alone or in combination with other drugs. Both randomized and nonrandomized studies were included for qualitative synthesis, only randomized studies were included for meta-analyses. Clinical overall response rate (cORR), prostate-specific antigen overall response rate (sORR), progression-free survival (PFS), overall survival (OS), and toxicity were the outcomes of interest.

RESULTS

We identified 53 studies delivering platinum agents for patients with CRPC. cORR varied from 0 to 82%, while sORR varied from 2% to 100%. Response rates were higher in patients who received combination treatments rather than platinum compounds alone. Pooled data from randomized trials demonstrated a statistically significant increase in both cORR (odds ratio = 5.3; 95% confidence interval, 1.89-14.92) and sORR (odds ratio = 2.07; 95% confidence interval, 1.33-3.22) when adding platinum compounds to chemotherapy. PFS varied from 2.1 to 12 months and OS 4.2 to 28 months with platinum-containing chemotherapy. Nausea and myelosuppression were the most common adverse effects. Toxicity was manageable in most studies.

CONCLUSION

Platinum compounds are a safe and active treatment for CRPC. Response rates are higher when cytotoxic chemotherapy containing platinum agents are compared to nonplatinum chemotherapy. Data on OS and PFS are inconclusive. More research is needed to evaluate whether platinum-based chemotherapy results in a survival benefit for patients with CRPC, as well as to establish predictive biomarkers.

Mitochondrial functions and melatonin: a tour of the reproductive cancers

Cancers of the reproductive organs have a strong association with mitochondrial defects, and a deeper understanding of the role of this organelle in preneoplastic-neoplastic changes is important to determine the appropriate therapeutic intervention. Mitochondria are involved in events during cancer development, including metabolic and oxidative status, acquisition of metastatic potential, resistance to chemotherapy, apoptosis, and others. Because of their origin from melatonin-producing bacteria, mitochondria are speculated to produce melatonin and its derivatives at high levels; in addition, exogenously administered melatonin accumulates in the mitochondria against a concentration gradient. Melatonin is transported into tumor cell by GLUT/SLC2A and/or by the PEPT1/2 transporters, and plays beneficial roles in mitochondrial homeostasis, such as influencing oxidative phosphorylation and electron flux, ATP synthesis, bioenergetics, calcium influx, and mitochondrial permeability transition pore. Moreover, melatonin promotes mitochondrial homeostasis by regulating nuclear DNA and mtDNA transcriptional activities. This review focuses on the main functions of melatonin on mitochondrial processes, and reviews from a mechanistic standpoint, how mitochondrial crosstalk evolved in ovarian, endometrial, cervical, breast, and prostate cancers relative to melatonin's known actions. We put emphasis on signaling pathways whereby melatonin interferes within cancer-cell mitochondria after its administration. Depending on subtype and intratumor metabolic heterogeneity, melatonin seems to be helpful in promoting apoptosis, anti-proliferation, pro-oxidation, metabolic shifting, inhibiting neovasculogenesis and controlling inflammation, and restoration of chemosensitivity. This results in attenuation of development, progression, and metastatic potential of reproductive cancers, in addition to lowering the risk of recurrence and improving the life quality of patients.

Systemic treatment for metastatic prostate cancer

The management of metastatic prostate cancer (mPCa) has changed over the past ten years. Several new drugs have been approved with significant overall survival benefits in metastatic castration resistant prostate cancer (PCa) including chemotherapy (docetaxel, cabazitaxel), new hormonal therapies (abiraterone, enzalutamide), Radium-223 and immunotherapy. The addition of docetaxel to androgen deprivation therapy (ADT) versus ADT alone in the castration sensitive metastatic setting has gained significant overall survival benefit particularly for high volume disease. More recently two phase III trials have assessed the efficacy of abiraterone plus prednisone plus ADT over ADT alone in newly high risk castrate sensitive mPCa. Determination of the appropriate treatment sequence using these therapies is important for maximizing the clinical benefit in castration sensitive and castration resistant PCa patients. Emerging fields are the identification of new subtypes with molecular characterization and new therapeutic targets.

Comparative study of the binding mode between cytochrome P450 17A1 and prostate cancer drugs in the absence of haem iron

According to the X-ray crystal structures of CYP17A1 (including its complexes with inhibitors), it is shown that a hydrogen bond exists between CYP17A1 and its inhibitors (such as abiraterone and TOK-001). Previous short MD simulations (50 ns) suggested that the binding of abiraterone to CYP17A1 is stronger than that of TOK-001. In this work, by carrying out long atomistic MD simulations (200 ns) of CYP17A1 and its complexes with abiraterone and TOK-001, we observed a binding mode between CYP17A1 and abiraterone, which is different from the binding mode between CYP17A1 and TOK-001. In the case of abiraterone binding, the unfilled volume in the active site cavity increases the freedom of movement of abiraterone within CYP17A1, leading to the collective motions of the helices G and B' as well as the breaking of hydrogen bond existing between the 3β-OH group of abiraterone and N202 of CYP17A1. However, the unfilled volume in the active site cavity can be occupied by the benzimidazole ring of TOK-001, restraining the motion of TOK-001. By pulling the two inhibitors (abiraterone and TOK-001) out of the binding pocket in CYP17A1, we discovered that abiraterone and TOK-001 were moved from their binding sites to the surface of protein similarly through the channels formed by the helices G and B'. In addition, based on the free energy calculations, one can see that it is energetically favorable for the two inhibitors (abiraterone and TOK-001) to enter into the binding pocket in CYP17A1.

TGF-β receptor I inhibitor enhances response to enzalutamide in a pre-clinical model of advanced prostate cancer

BACKGROUND

Prostate cancer progression is navigated by the androgen receptor (AR) and transforming-growth factor-β (TGF-β) signaling. We previously demonstrated that aberrant TGF-β signaling accelerates prostate tumor progression in a transgenic mouse model of prostate cancer via effects on epithelial-mesenchymal transition (EMT), driving castration-resistant prostate cancer (CRPC).

METHODS

This study examined the antitumor effect of the combination of TGF-β receptor I (TβRI) inhibitor, galunisertib, and FDA-approved antiandrogen enzalutamide, in our pre-clinical model. Age-matched genotypically characterized DNTGFβRII male mice were treated with either galunisertib and enzalutamide, in combination or as single agents in three "mini"-trials and the effects on tumor growth, phenotypic EMT, and actin cytoskeleton were evaluated.

RESULTS

Galunisertib in combination with enzalutamide significantly suppressed prostate tumor growth, by increasing apoptosis and decreasing cell proliferation of tumor cell populations compared to the inhibitor as a monotherapy (P < 0.05). The combination treatment dramatically reduced cofilin levels, actin cytoskeleton regulator, compared to single agents. Treatment with galunisertib targeted nuclear Smad4 protein (intracellular TGF-β effector), but had no effect on nuclear AR. Consequential to TGF-β inhibition there was an EMT reversion to mesenchymal-epithelial transition (MET) and re-differentiation of prostate tumors. Elevated intratumoral TGF-β1 ligand, in response to galunisertib, was blocked by enzalutamide.

CONCLUSION

Our results provide novel insights into the therapeutic value of targeting TGF-β signaling to overcome resistance to enzalutamide in prostate cancer by phenotypic reprogramming of EMT towards tumor re-differentiation and cytoskeleton remodeling. This translational work is significant in sequencing TGF-β blockade and antiandrogens to optimize therapeutic response in CRPC.

Incidence of fatigue and low-dose corticosteroid use in prostate cancer patients receiving systemic treatment: a meta-analysis of randomized controlled trials

BACKGROUND

Cancer-related fatigue (CRF) is a complex condition that is reported in > 50% of cancer patients. In men with castration-resistant prostate cancer (CRPC), CRF was reported in 12-21% of patients. Approved systemic therapy against CRPC is commonly administered in combination with androgen-deprivation treatment (ADT) and, in some cases, with daily, low-dose corticosteroids. Importantly, the use of low-dose corticosteroids is associated with multiple negative effects, including reduced muscle mass. On these grounds, we hypothesized that the chronic use of corticosteroids may increase the incidence of fatigue in patients with prostate cancer.

METHODS

We reviewed all randomized trials published during the last 15 years conducted in patients with prostate cancer receiving systemic treatment and we performed a sub-group analysis to gather insights regarding the potential differences in the incidence of fatigue in patients receiving vs. not receiving daily corticosteroids as part of their systemic anti-neoplastic regimen.

RESULTS

Overall, 22,734 men enrolled in prospective randomized phase II and III trials were evaluable for fatigue. Estimated pooled incidence of grade 1-2 fatigue was 30.89% (95% CI = 25.34-36.74), while estimated pooled incidence of grade 3-4 fatigue was reported in 3.90% (95% CI = 2.91-5.02). Sub-group analysis showed that grade 3-4 fatigue was approximately double in patients who received daily corticosteroids as part of their anti-neoplastic treatment (5.58; 95% CI = 4.33-6.98) vs. those who did not (2.67%; 95% CI = 1.53-4.11).

CONCLUSION

Our findings highlight the need for ad hoc-designed prospective clinical trials to investigate whether the benefits associated with low-dose, daily corticosteroids outweigh the risks associated with corticosteroid-related adverse events such as fatigue.

Optical study of chemotherapy efficiency in cancer treatment via intracellular structural disorder analysis using partial wave spectroscopy

As cancer progresses, macromolecules, such as DNA, RNA or lipids, inside cells undergo spatial structural rearrangements and alterations. Mesoscopic light transport-based optical partial wave spectroscopy (PWS) was recently introduced to quantify changes in the nanoscale structural disorder in biological cells. The PWS measurement is performed using a parameter termed as "disorder strength" (L _d ), which represents the degree of nanoscale structural disorder inside the cells. It was shown that cancerous cells have higher disorder strength than normal cells. In this work, we first used the PWS to analyze the hierarchy of different types of prostate cancer cells, namely, C4-2, DU-145 and PC-3, by quantifying their average disorder strengths. Results expectedly showed that L _d values increases in accordance with the increasing aggressiveness/tumorigenicity levels of these cells. Using the L _d parameter, we then analyzed the chemoresistance properties of these prostate cancer cells to docetaxel drug compared to their chemosensitivity. Results show that chemoresistant cancer cells have increased L _d values, that is, higher disorder strength, relative to chemosensitive cancer cells. Thus, use of the L _d metric can be effective in determining the efficacy of particular chemotherapy.

Emerging cell cycle inhibitors for treating metastatic castration-resistant prostate cancer

INTRODUCTION

Disease progression despite androgen suppression defines lethal castration-resistant prostate cancer (CRPC). Most of these cancers remain androgen receptor (AR)-signaling dependent. Therapy for metastatic CRPC includes abiraterone acetate, enzalutamide, docetaxel, cabazitaxel, sipuleucel-T, and radium-223. However, survival remains modest for men with progressive disease despite AR-targeted therapy and docetaxel, and therefore novel treatments are needed. Areas covered: Recent evidence of genomic heterogeneity and sensitivity to PARP inhibitors supports investigation of targeted agents in CRPC. Cell cycle inhibitors are therefore logical molecules to investigate. Review of the current literature identified cell cycle inhibitors under study in early phase clinical trials targeting the G1 (palbociclib, ribociclib, AZD-5363, ipatasertib), S (M-6620, prexasertib), G2 (adavosertib), and M (alisertib) phases of the cell cycle. Expert opinion: Strategies combining cell cycle inhibitors with active agents in CRPC are most likely to have clinical impact with CDK4/6 and Wee1 inhibitors appearing most promising. Identification of predictive biomarkers may be essential and currently trials are testing circulating cell-free DNA as an approach. Incremental toxicities such as neutropenia are important in this population. Results from most current clinical trials of cell cycle inhibitors in CRPC are still pending but it is anticipated they will provide important insights into the heterogeneous biology of CRPC.

Molecular underpinnings of enzalutamide resistance

Prostate cancer (PCa) is among the most common adult malignancies, and the second leading cause of cancer-related death in men. As PCa is hormone dependent, blockade of the androgen receptor (AR) signaling is an effective therapeutic strategy for men with advanced metastatic disease. The discovery of enzalutamide, a compound that effectively blocks the AR axis and its clinical application has led to a significant improvement in survival time. However, the effect of enzalutamide is not permanent, and resistance to treatment ultimately leads to development of lethal disease, for which there currently is no cure. This review will focus on the molecular underpinnings of enzalutamide resistance, bridging the gap between the preclinical and clinical research on novel therapeutic strategies for combating this lethal stage of prostate cancer.

The importance of patient-reported outcomes in clinical trials and strategies for future optimization

Patient-reported outcomes (PROs) can be included in clinical trials as primary or secondary endpoints and are increasingly recognized by regulators, clinicians, and patients as valuable tools to collect patient-centered data. PROs provide unique information on the impact of a medical condition and its treatment from the patient's perspective; therefore, PROs can be included in clinical trials to ensure the impact of a trial intervention is comprehensively assessed. This review first discusses examples of how PRO endpoints have added value to clinical trial interpretation. Second, it describes the problems with current practices in designing, implementing, and reporting PRO studies, and how these problems may be addressed by complying with guidance for protocol development, selecting appropriate PRO measures to match clinically motivated PRO hypotheses, minimizing the rates of avoidable missing PRO data, analyzing and interpreting PRO data, and transparently reporting PRO findings.

Enzalutamide therapy for advanced prostate cancer: efficacy, resistance and beyond

The androgen receptor drives the growth of metastatic castration-resistant prostate cancer. This has led to the development of multiple novel drugs targeting this hormone-regulated transcription factor, such as enzalutamide – a potent androgen receptor antagonist. Despite the plethora of possible treatment options, the absolute survival benefit of each treatment separately is limited to a few months. Therefore, current research efforts are directed to determine the optimal sequence of therapies, discover novel drugs effective in metastatic castration-resistant prostate cancer and define patient subpopulations that ultimately benefit from these treatments. Molecular studies provide evidence on which pathways mediate treatment resistance and may lead to improved treatment for metastatic castration-resistant prostate cancer. This review provides, firstly a concise overview of the clinical development, use and effectiveness of enzalutamide in the treatment of advanced prostate cancer, secondly it describes translational research addressing enzalutamide response vs resistance and lastly highlights novel potential treatment strategies in the enzalutamide-resistant setting.

Current therapeutic options in metastatic castration-resistant prostate cancer

BACKGROUND

The tumors of many patients with prostate cancer eventually become refractory to androgen deprivation therapy with progression to metastatic castration-resistant disease. Significant advances in the treatment of metastatic castration-resistant prostate cancer (mCRPC) have been made in recent years, and new treatment strategies have recently been made available. The aim of this report was to schematically review all the approved pharmacologic treatment options for patients with mCRPC through 2018, analyzing the efficacy and possible side effects of each therapy to assist clinicians in reaching an appropriate treatment decision. New biomarkers potentially of aid in the choice of treatment in this setting are also briefly reviewed.

METHODS

We performed a literature search of clinical trials of new drugs and treatments for patients diagnosed with mCRPC published through 2018.

RESULTS

Two new hormonal drugs, abiraterone acetate and enzalutamide have been approved by FDA in 2011 and 2012, respectively for the treatment of patients with mCRPC and have undergone extensive testing. While these treatments have shown a benefit in progression-free and overall survival, the appropriate sequencing must still be determined so that treatment decisions can be made based on their specific clinical profile. Cabazitaxel has been shown to be an efficient therapeutic option in a postdocetaxel setting, while its role in chemotherapy-naïve patients must still be determined. Sipuleucel-T and radium-223 have been studied in patients without visceral metastases and have achieved overall survival benefits with good safety profiles. The feasibility and efficacy of combinations of new treatments with other known therapies such as chemotherapy are currently under investigation.

CONCLUSIONS

Drug development efforts continue to attempt to prolong survival and improve quality of life in the mCRPC setting, with several therapeutic options available. Ongoing and future trials are needed to further assess the efficacy and safety of these new drugs and their interactions, along with the most appropriate sequencing.

Medical management of metastatic prostate cancer

Androgen deprivation therapy has an important role in the medical treatment of advanced and metastatic prostate cancer

The treatment of metastatic prostate cancer is influenced by whether the patient’s disease has progressed on androgen deprivation therapy or not It is considered to be castrate-resistant disease if the cancer has progressed despite adequate suppression of androgens

Chemotherapy using docetaxel or cabazitaxel and anti-androgen drugs such as abiraterone and enzalutamide can be used to treat castrate-resistant disease Radium-223 is an option for patients with bony metastases

Metastatic castrate-resistant prostate cancer is now considered a chronic illness as the life expectancy of patients has almost doubled due to the new treatments General practitioners are therefore more likely to encounter patients with disease- and treatment-related complications

Systematic Review and Network Meta-Analysis of Treatments for Chemotherapy-Naive Patients with Asymptomatic/Mildly Symptomatic Metastatic Castration-Resistant Prostate Cancer

OBJECTIVES

To estimate the relative effectiveness of enzalutamide in chemotherapy-naive metastatic castration-resistant prostate cancer by conducting a systematic literature review and a network meta-analysis (NMA).

METHODS

A systematic literature review identified randomized controlled trials comparing enzalutamide, abiraterone/prednisone, radium-223, sipuleucel-T, or docetaxel with each other or placebo in chemotherapy-naive or mixed populations (with and without prior chemotherapy) with asymptomatic/mildly symptomatic metastatic castration-resistant prostate cancer. Feasibility assessment evaluated the trials' suitability for NMA inclusion. The main outcomes were hazard ratios (HRs) for overall survival (OS) and radiographic progression-free survival (rPFS).

RESULTS

Searches of relevant bibliographic databases, trial registers, Web sites, and conference abstracts conducted in October 2014 identified 25,712 records. Ten randomized controlled trials were eligible for the NMA. Enzalutamide was superior to placebo for OS and rPFS (fixed-effects model). NMA results (fixed-effects model) showed no evidence of a difference between enzalutamide and abiraterone/prednisone (HR 0.95 [95% CrI 0.77-1.16]), sipuleucel-T (HR 1.07 [95% CrI 0.84-1.37]), or radium-223 (HR 1.10 [95% CrI 0.87-1.37]) for OS. HRs were similar for the random-effects model. Nevertheless, results (fixed-effects model) suggested that enzalutamide was superior to abiraterone/prednisone (HR 0.59 [95% CrI 0.48-0.72]) and sipuleucel-T (HR 0.32 [95% CrI 0.25-0.42]) for rPFS. Results also suggested superiority of enzalutamide versus placebo, abiraterone/prednisone, or sipuleucel-T for time to chemotherapy.

CONCLUSIONS

For rPFS, the NMA suggests that enzalutamide is superior to abiraterone/prednisone and sipuleucel-T. There is no evidence of a statistically significant difference in OS between enzalutamide and abiraterone/prednisone, sipuleucel-T, or radium-223. Given the limitations in network construction and underlying assumptions made to complete these analyses, results should be interpreted with caution.

Bayesian Multiparameter Evidence Synthesis to Inform Decision Making: A Case Study in Metastatic Hormone-Refractory Prostate Cancer

In health technology assessment, decisions are based on complex cost-effectiveness models that require numerous input parameters. When not all relevant estimates are available, the model may have to be simplified. Multiparameter evidence synthesis combines data from diverse sources of evidence, which results in obtaining estimates required in clinical decision making that otherwise may not be available. We demonstrate how bivariate meta-analysis can be used to predict an unreported estimate of a treatment effect enabling implementation of a multistate Markov model, which otherwise needs to be simplified. To illustrate this, we used an example of cost-effectiveness analysis for docetaxel in combination with prednisolone in metastatic hormone-refractory prostate cancer. Bivariate meta-analysis was used to model jointly available data on treatment effects on overall survival and progression-free survival (PFS) to predict the unreported effect on PFS in a study evaluating docetaxel with prednisolone. The predicted treatment effect on PFS enabled implementation of a 3-state Markov model comprising stable disease, progressive disease, and dead states, while lack of the estimate restricted the model to a 2-state model (with alive and dead states). The 2-state and 3-state models were compared by calculating the incremental cost-effectiveness ratio (which was much lower in the 3-state model: £22,148 per quality-adjusted life year gained compared to £30,026 obtained from the 2-state model) and the expected value of perfect information (which increased with the 3-state model). The 3-state model has the advantage of distinguishing surviving patients who progressed from those who did not progress. Hence, the use of advanced meta-analytic techniques allowed obtaining relevant parameter estimates to populate a model describing disease pathway in more detail while helping to prevent valuable clinical data from being discarded.

Opportunities and challenges of incorporating clinical outcome assessments in brain tumor clinical trials

Regulatory agencies have progressively emphasized the importance of assessing broader aspects of patient well-being to better define therapeutic gain. As a result, clinical outcome assessments (COAs) are increasingly used to evaluate the impact, both positive and negative, of cancer treatments and in some instances have played a major factor in the regulatory approval of drugs. Challenges remain, however, in the routine incorporation of these measures in cancer clinical trials, particularly in brain tumor studies. Factors unique to brain tumor patients such as cognitive decline and language dysfunction may hamper their successful implementation. Study designs often relegated these outcome measures to exploratory endpoints, further compromising data completion. New strategies are needed to maximize the complementary information that COAs could add to clinical trials alongside more traditional measures such as progression-free and overall survival. The routine incorporation of COAs as either primary or secondary objectives with attention to minimizing missing data should define a novel clinical trial design. We provide a review of the approaches, challenges, and opportunities for incorporating COAs into brain tumor clinical research, providing a perspective for integrating these measures into clinical trials.

Corticosteroid use endpoints in neuro-oncology: Response Assessment in Neuro-Oncology Working Group

Background

Corticosteroids are the mainstay of treatment for peritumor edema but are often associated with significant side effects. Therapies that can reduce corticosteroid use would potentially be of significant benefit to patients. However, currently there are no standardized endpoints evaluating corticosteroid use in neuro-oncology clinical trials.

Methods

The Response Assessment in Neuro-Oncology (RANO) Working Group has developed consensus recommendations for endpoints evaluating corticosteroid use in clinical trials in both adults and children with brain tumors.

Results

Responders are defined as patients with a 50% reduction in total daily corticosteroid dose compared with baseline or reduction of the total daily dose to ≤2 mg of dexamethasone (or equivalent dose of other corticosteroid); baseline dose must be at least 4 mg of dexamethasone daily (or equivalent dose of other corticosteroids) for at least one week. Patients must have stable or improved Neurologic Assessment in Neuro-Oncology (NANO) score or Karnofsky performance status score or Eastern Cooperative Oncology Group (ECOG) (Lansky score for children age <16 y), and an improved score on a relevant clinical outcome assessment tool. These criteria must be sustained for at least 4 weeks after baseline assessment to be considered a response, and are confirmed 4 weeks after that (ie, 8 wk after baseline assessment) to be considered a sustained response.

Conclusions

This RANO proposal for corticosteroid use endpoints in neuro-oncology clinical trials may need to be refined and will require prospective validation in clinical studies.

Patient-reported outcomes for patients with metastatic castration-resistant prostate cancer receiving docetaxel and Atrasentan versus docetaxel and placebo in a randomized phase III clinical trial (SWOG S0421)

Background

SWOG S0421 was a large randomized trial comparing docetaxel/prednisone plus placebo (DPP) to docetaxel/prednisone plus atrasentan over 12 cycles for patients with metastatic castration-resistant prostate cancer (mCRPC). The current report presents the PRO results for this trial, an important secondary endpoint.

Methods

The trial specified two primary PRO endpoints. Palliation of worst pain was based on the Brief Pain Inventory (BPI), where a 2 point difference is defined as clinically meaningful. Improvement of functional status was based on the Functional Assessment of Cancer Therapy – Prostate Cancer Trial Outcome Index (FACT-P TOI); a 5-point difference has been defined as clinically meaningful. We compared rates by arm using chi-square tests. Longitudinal analyses using linear mixed models addressed changes by arm over time.

Results

Four-hundred eighty-nine patients on each arm were evaluable for PRO endpoint data. There were no differences by arm in clinically meaningful pain palliation (41.7% for DPP vs. 44.0% for DPA, p = .70) or functional status (24.2% for DPP vs. 28.7% for DPA, p = .13). Longitudinal comparisons indicated no differences over time by arm for BPI Worst Pain scores (0.13 points, p = .23). Patients on the DPA arm had improved functional status of 1.78 points on average, a statistically significant (p = .02) but not clinically meaningful difference.

Conclusions

The SWOG S0421 PRO data showed little evidence of clinically meaningful differences by arm in either pain palliation or functional status.

Electronic supplementary material

The online version of this article (10.1186/s41687-018-0054-5) contains supplementary material, which is available to authorized users.

The efficacy and safety comparison of docetaxel, cabazitaxel, estramustine, and mitoxantrone for castration-resistant prostate cancer: A network meta-analysis

AIMS

The aim of this study was to compare the efficacy and safety of docetaxel, cabazitaxel, docetaxel + estramustine, mitoxantrone in the management of castration-resistant prostate cancer (CRPC).

METHODS

Electronic databases including PubMed, Cochrance Library and Embase were searched for studies published from when the databases were established to January 1st, 2018. Randomized controlled trials (RCTs) that compared docetaxel + prednisone (DP), cabazitaxel + prednisone (CP), docetaxel + estramustine + prednisone (DEP), and mitoxantrone + cabazitaxel + prednisone (MP) for CRPC treatment were identified. The network meta-analysis was conducted with software R 3.3.2. We analyzed the main outcomes, including the overall survival (OS), progression-free survival (PFS), prostate-specific antigen (PSA) response, tumor response and severe adverse events (AEs). Ranking of the chemotherapeutic agents was based on probabilities of interventions for each of the outcomes that were performed. The consistency of direct and indirect evidence was assessed by node splitting.

RESULTS

10 RCTs, with 3590 patients, were analyzed. The network meta-analysis results revealed that CP significantly increased OS, PFS, PSA response, tumor response, and severe AEs compared to MP. DP showed similar results with CP except for tumor response, where it showed slight inferiority in effectiveness. DEP was associated with clearly improved outcomes in PFS, PSA response and tumor response compared to those of MP, but this was not the case for OS benefit and severe AEs. No significant difference was detected in DP, CP and DEP except for the outcomes of severe AEs. MP was less effective in survival and clinical benefit, but much safer in safety outcomes than other chemotherapy agents. The probabilities of rank plots showed that CP ranked first in OS and tumor response; DEP ranked first in PFS time and PSA response; MP was the best treatment mode for safety.

CONCLUSIONS

DP and CP survival benefit (OS, PFS) and clinical benefit (PSA response and tumor response) were comparable, as well as their associated AEs. DEP was associated with less survival benefit, similar clinical improvement and more AEs than DP or CP. MP had the lowest survival and clinical benefit but excellent safety than other agents. Based on evidences of current results, we recommended CP as the most suitable chemotherapy agent for CRPC patients, followed by DP, MP as third, and DEP as the last choice. However, considering limitations of our network meta-analysis, additional high-quality studies are needed for further evaluation.

The Kraken Wakes: induced EMT as a driver of tumour aggression and poor outcome

Epithelial mesenchymal transition (EMT) describes the shift of cells from an epithelial form to a contact independent, migratory, mesenchymal form. In cancer the change is linked to invasion and metastasis. Tumour conditions, including hypoxia, acidosis and a range of treatments can trigger EMT, which is implicated in the subsequent development of resistance to those same treatments. Consequently, the degree to which EMT occurs may underpin the entire course of tumour progression and treatment response in a patient. In this review we look past the protective effect of EMT against the initial treatment, to the role of the mesenchymal state, once triggered, in promoting disease growth, spread and future treatment insensitivity. In patients a correlation was found between the propensity of a treatment to induce EMT and failure of that treatment to provide a survival benefit, implicating EMT induction in accelerated tumour progression after treatment cessation. Looking to the mechanisms driving this detrimental effect; increased proliferation, suppressed apoptosis, stem cell induction, augmented angiogenesis, enhanced metastatic dissemination, and immune tolerance, can all result from treatment-induced EMT and could worsen outcome. Evidence also suggests EMT induction with earlier therapies attenuates benefits of later treatments. Looking beyond epithelial tumours, de-differentiation also has therapy-attenuating effects and reversal thereof may yield similar rewards. A range of potential therapies are in development that may address the diverse mechanisms and molecular control systems involved in EMT-induced accelerated progression. Considering the broad reaching effects of mesenchymal shift identified, successful deployment of such treatments could substantially improve patient outcomes.

Can RECIST response predict success in phase 3 trials in men with metastatic castration-resistant prostate cancer?

BACKGROUND

Intermediate endpoints are needed in early phase studies of men with metastatic castration-resistant prostate cancer (mCRPC) that can reliably predict success in phase 3 trials. Among men with measurable disease, objective response may provide information as to whether a treatment is likely to be successful.

METHODS

We conducted a systematic review of systemic agents that have proceeded to phase 3 trials in men with mCRPC and examined the relationship between improvements in measurable disease response in phase 2 trials and successful phase 3 trials leading to regulatory approval. Only trials that included men with radiographically measurable disease were included.

RESULTS

We examined 31 eligible mCRPC phase 3 trials between 1992 and 2017 and 29 of the preceding phase 2 trials for RECIST responses. Measurable tumor responses in phase 2 trials were higher for successful therapies in phase 3 trials in chemotherapy-naive men with mCRPC, but were less correlated with success in trials investigating docetaxel combination regimens or the post chemotherapy mCRPC setting. Many failed agents did not produce higher than expected response rates over control arms; however, several agents such as anti-angiogenic therapies or orteronel produced higher than expected responses without survival benefit.

CONCLUSIONS

Objective responses in men with mCRPC may be associated with prolonged survival, but this association is mechanism dependent and inconsistent across trials or disease states. These data support considering RECIST response as a supportive but not sole endpoint in phase 2 trials to support launching phase 3 trials.

Treatment of Advanced Prostate Cancer-A Review of Current Therapies and Future Promise

Despite many recent advances in the therapy for metastatic castration-resistant prostate cancer (mCRPC), the disease remains incurable, although men suffering from this disease are living considerably longer. In this review, we discuss the current treatment options available for this disease, such as taxane-based chemotherapy, the novel hormone therapies abiraterone and enzalutamide, and treatments such as radium-223 and sipuleucel-T. We also highlight the need for ongoing research in this field, because, despite numerous recent advances, the prognosis for mCRPC remains poor. Furthermore, as a growing body of evidence shows the increasing heterogeneity of the disease, and highlights the ongoing need for disease molecular stratification and validation/qualification of predictive biomarkers, we explore this burgeoning research space that is likely to transform how we treat this disease. We describe putative predictive biomarkers, including androgen receptor splice variants, phosphatase and tensin homolog (PTEN) loss, homologous recombination repair defects, including BRCA2 loss, and mismatch repair defects. The development of next-generation sequencing techniques and the routine biopsy of metastatic disease have driven significant advances in our understanding of the genomics of cancer, and are now poised to transform our treatment of this disease.

Chemotherapy and radiation for prostate cancer

Over the past few decades there is growing appreciation for the role of chemotherapy in treatment of prostate cancer. Initial successful phase III randomized trials in castration resistant prostate cancer (CRPC) have led to additional successful trials in earlier presentations of disease. Given the established role of radiation in management of locally advanced disease and demonstrated efficacy of taxanes in treatment of prostate cancer, optimal combination of radiation and chemotherapy in this patient population has garnered increased attention. Successful phase III trials in this space have given additional stimulus to further exploring combination therapy with radiation. New directions include assessment of additional chemotherapeutic agents including cabazitaxel and PARP inhibitors as well as personalization of therapy with use of genomic testing and other emerging markers to guide therapeutic decisions.

Phase III Intergroup Trial of Adjuvant Androgen Deprivation With or Without Mitoxantrone Plus Prednisone in Patients With High-Risk Prostate Cancer After Radical Prostatectomy: SWOG S9921

Purpose Patients with high-risk prostate cancer after radical prostatectomy are at risk for death. Adjuvant androgen-deprivation therapy (ADT) may reduce this risk. We hypothesized that the addition of mitoxantrone and prednisone (MP) to adjuvant ADT could reduce mortality compared with adjuvant ADT alone. Methods Eligible patients had cT1-3N0 prostate cancer with one or more high-risk factors after radical prostatectomy (Gleason score [GS] ≥ 8; pT3b, pT4, or pN+ disease; GS 7 and positive margins; or preoperative prostate-specific antigen [PSA] > 15 ng/mL, biopsy GS score > 7, or PSA > 10 ng/mL plus biopsy GS > 6. Patients with PSA ≤ 0.2 ng/mL after radical prostatectomy were stratified by pT/N stage, GS, and adjuvant radiation plan and randomly assigned to ADT (bicalutamide and goserelin for 2 years) or ADT plus six cycles of MP. The primary end point was overall survival (OS). Median OS was projected to be 10 years in the ADT arm, requiring 680 patients per arm to detect a hazard ratio of 1.30 with 92% power and one-sided α = .05. Results Nine hundred sixty-one eligible intent-to-treat patients were randomly assigned to ADT or ADT + MP from October 1999 to January 2007, when the Data Safety Monitoring Committee recommended stopping accrual as a result of higher leukemia incidence with ADT + MP. Median follow-up was 11.2 years. The 10-year OS estimates were 87% with ADT (expected 50%) and 86% with ADT + MP (hazard ratio, 1.06; 95% CI, 0.79 to 1.43). The 10-year estimate for disease-free survival was 72% for both arms. Prostate cancer was the cause of death in 18% of patients in the ADT arm and 22% in the ADT + MP arm. More patients in the MP arm died of other cancers (36% v 18% in ADT alone arm). Conclusion MP did not improve OS and increased deaths from other malignancies. The DFS and 10-year OS in these patients treated with 2 years of ADT were encouraging compared with historical estimates, although a definitive conclusion regarding value of ADT may not be made without a nontreatment control arm.

Role of chemotherapy in prostate cancer

Chemotherapy in prostate cancer (PCa) has undergone dramatic landscape changes. While earlier studies utilized varying chemotherapy regimens which were found to be largely palliative in nature and hardly resulted in durable or meaningful responses, docetaxel resulted in the first chemotherapy agent that showed improvement in overall survival in metastatic castration-resistant prostate cancer (mCRPC). However, combination chemotherapy or any agents added to docetaxel have failed to yield incremental benefits. The improvement in overall survival as well as secondary endpoints of prostate-specific antigen (PSA) and time to recurrence when using docetaxel in the metastatic hormone-sensitive state has changed the standard of care for treatment of newly diagnosed de novo metastatic PCa. There are also promising results in locally advanced PCa and high-risk PCa in both the neoadjuvant and adjuvant settings. This review summarizes the historical as well as the more contemporary use of chemotherapeutic agents in PCa in varying states and phases of disease.

Hormone Refractory Prostate Cancer (Hrpc): Present and Future Approaches of Therapy

The mainstay of therapy for patients with advanced prostate cancer still remains androgen deprivation, although response to this is invariably temporary. Most of the patients develop hormone-refractory disease resulting in progressive clinical deterioration and, ultimately, death. Until recently there has been no standard chemotherapeutic approach for hormone refractory prostate cancer (HRPC), the major benefits of chemotherapy being only palliative. The studies combining mitoxantrone plus a corticosteroid demonstrated that chemotherapy could be given to men with symptomatic HRPC with minimal toxicity and a significant palliation could be provided. Recently, results from 2 phase III randomized clinical trials demonstrating that a combination of docetaxel plus prednisone can improve survival in men with HRPC have propelled docetaxel-based therapy into the forefront of treatment options for these patients as the new standard of care. There is a promising activity of new drug combinations such as taxanes plus vinca alkaloids; bisphosphonates are assuming a prominent role in prostate therapy through their ability to prevent skeletal morbidity. Combinations of classic chemotherapeutic agents and biological drugs began to be tested in phase II-III trials and the first results appear interesting. This article focuses on combinations recently evaluated or under clinical development for the treatment of HRPC.

Is There a Standard Chemotherapeutic Regimen for Hormone-Refractory Prostate Cancer? Present and Future Approaches in the Management of the Disease

Prostate cancer that no longer responds to hormonal manipulation can be defined as hormone-refractory prostate cancer. Until recently, there has been no standard chemotherapeutic approach for hormone-refractory prostate cancer. The major benefits of chemotherapy in the treatment of the disease are palliative in nature, in terms of reduction of pain and use of analgesics and improvement of performance status, as followed in the most recent trials. Phase III studies are necessary to better evaluate the efficacy of the different regimens, because several old studies suffer for methodological deficits. There is a promising activity of new drug combinations, such as vinca alkaloids and taxanes. Phase I and II trial are testing combinations of classic chemotherapeutic agents and biologic drugs, and the first results appear interesting. In this article, recent advances in the treatment of hormone-refractory prostate cancer using chemotherapeutic regimens are critically reviewed.

Vinorelbine and Prednisone in older Cancer Patients with Hormone-Refractory Metastatic Prostate Cancer a Phase II Study

Aims and Background

Prostate cancer is a common disease in older men. Since it is hormone resistant, no treatment may improve survival. In patients with hormone-refractory prostate cancer, clinical benefit is an important treatment end point.

Study Design

This study evaluated the efficacy and toxicity of a vinorelbine and prednisone combination in hormone-refractory prostate cancer patients. Vinorelbine was administered at the dose of 25 mg/m2 on days 1 and 8, every three weeks; prednisone was administered orally at the dose of 12 mg/day. Thirty consecutive patients, 65 years or older, with progressive (PSA increase or increase in bidimensionally measurable lesion) metastatic prostate adenocarcinoma were enrolled. Four patients (13%) had a partial response and 14 (46%) stable disease. Time to progression for the entire group was 4.5 months (range, 2–13) and 7.5 months for the group of responders (range, 3–13). A PSA decrease >50% was registered in 36% of the patients. Pain reduction was recorded in 44.4% of the patients and stability in 14.8%.

Results

The treatment was well tolerated and grade 3 toxicity was found in 2 cases of anemia and 2 cases of leukopenia without fever.

Conclusions

The schedule is able to control the evolution of hormone-refractory prostate cancer and to give a clinical benefit. These results provide information for further clinical trials in a large series of elderly cancer patients.