Randomized, open-label phase III trial of docetaxel plus high-dose calcitriol versus docetaxel plus prednisone for patients with castration-resistant prostate cancer

Clinical validation of circulating GDF15/MIC-1 as a marker of response to docetaxel and survival in men with metastatic castration-resistant prostate cancer

BACKGROUND

Elevated circulating growth differentiation factor (GDF15/MIC-1), interleukin 4 (IL4), and IL6 levels were associated with resistance to docetaxel in an exploratory cohort of men with metastatic castration-resistant prostate cancer (mCRPC). This study aimed to establish level 2 evidence of cytokine biomarker utility in mCRPC.

METHODS

IntVal: Plasma samples at baseline (BL) and Day 21 docetaxel (n = 120). ExtVal: Serum samples at BL and Day 42 of docetaxel (n = 430). IL4, IL6, and GDF15 levels were measured by ELISA. Monocytes and dendritic cells were treated with 10% plasma from men with high or low GDF15 or recombinant GDF15.

RESULTS

IntVal: Higher GDF15 levels at BL and Day 21 were associated with shorter overall survival (OS) (BL; p = 0.03 and Day 21; p = 0.004). IL4 and IL6 were not associated with outcomes. ExtVal: Higher GDF15 levels at BL and Day 42 predicted shorter OS (BL; p < 0.0001 and Day 42; p < 0.0001). Plasma from men with high GDF15 caused an increase in CD86 expression on monocytes (p = 0.03), but was not replicated by recombinant GDF15.

CONCLUSIONS

Elevated circulating GDF15 is associated with poor prognosis in men with mCRPC receiving docetaxel and may be a marker of changes in the innate immune system in response to docetaxel resistance. These findings provide a strong rationale to consider GDF15 as a biomarker to guide a therapeutic trial of drugs targeting the innate immune system in combination with docetaxel in mCRPC.

Discordant Health Implications and Molecular Mechanisms of Vitamin D in Clinical and Preclinical Studies of Prostate Cancer: A Critical Appraisal of the Literature Data

Clinical and preclinical studies have provided conflicting data on the postulated beneficial effects of vitamin D in patients with prostate cancer. In this opinion piece, we discuss reasons for discrepancies between preclinical and clinical vitamin D studies. Different criteria have been used as evidence for the key roles of vitamin D. Clinical studies report integrative cancer outcome criteria such as incidence and mortality in relation to vitamin D status over time. In contrast, preclinical vitamin D studies report molecular and cellular changes resulting from treatment with the biologically active vitamin D metabolite, 1,25-dihydroxyvitamin D3 (calcitriol) in tissues. However, these reported changes in preclinical in vitro studies are often the result of treatment with biologically irrelevant high calcitriol concentrations. In typical experiments, the used calcitriol concentrations exceed the calcitriol concentrations in normal and malignant prostate tissue by 100 to 1000 times. This raises reasonable concerns regarding the postulated biological effects and mechanisms of these preclinical vitamin D approaches in relation to clinical relevance. This is not restricted to prostate cancer, as detailed data regarding the tissue-specific concentrations of vitamin D metabolites are currently lacking. The application of unnaturally high concentrations of calcitriol in preclinical studies appears to be a major reason why the results of preclinical in vitro studies hardly match up with outcomes of vitamin D-related clinical studies. Regarding future studies addressing these concerns, we suggest establishing reference ranges of tissue-specific vitamin D metabolites within various cancer entities, carrying out model studies on human cancer cells and patient-derived organoids with biologically relevant calcitriol concentrations, and lastly improving the design of vitamin D clinical trials where results from preclinical studies guide the protocols and endpoints within these trials.

Vitamin D and cancer

The role of vitamin D in the prevention of chronic diseases including cancer, has received a great deal of attention during the past few decades. The term "Cancer" represents multiple disease states with varying biological complexities. The strongest link between vitamin D and cancer is provided by ecological and studies like observational, in preclinical models. It is apparent that vitamin D exerts diverse biological responses in a tissue specific manner. Moreover, several human factors could affect bioactivity of vitamin D. The mechanism(s) underlying vitamin D initiated anti-carcinogenic effects are diverse and includes changes at the muti-system levels. The oncogenic environment could easily corrupt the traditional role of vitamin D or could ensure resistance to vitamin D mediated responses. Several researchers have identified gaps in our knowledge pertaining to the role of vitamin D in cancer. Further areas are identified to solidify the role of vitamin D in cancer control strategies.

Conditional survival does not improve over time in metastatic castration-resistant prostate cancer patients undergoing docetaxel

PURPOSE

To investigate the conditional overall survival (OS) of metastatic castration-resistant prostate cancer (mCRPC) patients receiving docetaxel chemotherapy.

METHODS

We used deidentified patient-level data from the Prostate Cancer DREAM Challenge database and the control arm of the ENTHUSE 14 trial. We identified 2158 chemonaïve mCRPC patients undergoing docetaxel chemotherapy in the five randomized clinical trials. The 6-month conditional OS was calculated at times 0, 6, 12, 18, and 24 months from randomization. Survival curves of each group were compared using the log-rank test. Patients were then stratified into low- and high-risk groups based on the median predicted value of our recently published nomogram predicting OS in mCRPC patients.

RESULTS

Nearly half (45%) of the study population was aged between 65 and 74 years. Median interquartile range prostate-specific antigen for the overall cohort was 83.2 (29.6-243) ng/mL, and 59% of patients had bone metastasis with or without lymph node involvement. The 6-month conditional survival rates at 0, 6, 12, 18, and 24 months for the entire cohort were 93% (95% confidence interval [CI]: 92-94), 82% (95% CI: 81-84), 76% (95% CI: 73-78), 75% (95% CI: 71-78), and 71% (95% CI: 65-76). These rates were, respectively, 96% (95% CI: 95-97), 92% (95% CI: 90-93), 84% (95% CI: 81-87), 81% (95% CI: 77-85), and 79% (95% CI: 72-84) in the low-risk group and 89% (95% CI: 87-91), 73% (95% CI: 70-76), 65% (95% CI: 60-69), 64% (95% CI: 58-70), and 58% (95% CI: 47-67) in the high-risk group.

CONCLUSION

The conditional OS for patients undergoing docetaxel chemotherapy tends to plateau over time, with the main drop in conditional OS happening during the first year from initiating docetaxel treatment. That is the longer a patient survives, the more likely they are to survive further. This prognostic information could be a useful tool for a more accurate tailoring of both follow-up and therapies.

PATIENT SUMMARY

In this report, we looked at the future survival in months of patients with metastatic castration resistant prostate cancer on chemotherapy who have already survived a certain period. We found that the longer time that a patient survives, the more likely they will continue to survive. We conclude that this information will help physicians tailor follow-ups and treatments for patients for a more accurate personalized medicine.

The effects of vitamin D on all-cause mortality in different diseases: an evidence-map and umbrella review of 116 randomized controlled trials

Purpose

To conduct a solid evidence by synthesizing meta-analyses and updated RCTs about the effects of vitamin D on all-cause mortality in different health conditions.

Methods

Data sources: Pubmed, Embase, Web of Science, the Cochrane Library, Google Scholar from inception until 25th April, 2022. Study selection: English-language, meta-analyses and updated RCTs assessing the relationships between vitamin D and all-cause mortality. Data synthesis: Information of study characteristics, mortality, supplementation were extracted, estimating with fixed-effects model. A Measurement Tool to Assess Systematic Reviews, Grading of Recommendations Assessment, Development and Evaluation, and funnel plot was used to assess risk of bias. Main outcomes: All-cause mortality, cancer mortality, cardiovascular disease mortality.

Results

In total of 27 meta-analyses and 19 updated RCTs were selected, with a total of 116 RCTs and 149, 865 participants. Evidence confirms that vitamin D reduces respiratory cancer mortality (RR, 0.56 [95%CI, 0.33 to 0.96]). All-cause mortality is decreased in patients with COVID-19 (RR, 0.54[95%CI, 0.33 to 0.88]) and liver diseases (RR, 0.64 [95%CI, 0.50 to 0.81]), especially in liver cirrhosis (RR, 0.63 [95%CI, 0.50 to 0.81]). As for other health conditions, such as the general health, chronic kidney disease, critical illness, cardiovascular diseases, musculoskeletal diseases, sepsis, type 2 diabetes, no significant association was found between vitamin D and all-cause mortality.

Conclusions

Vitamin D may reduce respiratory cancer mortality in respiratory cancer patients and all-cause mortality in COVID-19 and liver disorders' patients. No benefits showed in all-cause mortality after vitamin D intervention among other health conditions. The hypothesis of reduced mortality with vitamin D still requires exploration.

Systematic review registration

https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=252921, identifier: CRD42021252921.

OSCAR: Optimal subset cardinality regression using the L0-pseudonorm with applications to prognostic modelling of prostate cancer

In many real-world applications, such as those based on electronic health records, prognostic prediction of patient survival is based on heterogeneous sets of clinical laboratory measurements. To address the trade-off between the predictive accuracy of a prognostic model and the costs related to its clinical implementation, we propose an optimized L0-pseudonorm approach to learn sparse solutions in multivariable regression. The model sparsity is maintained by restricting the number of nonzero coefficients in the model with a cardinality constraint, which makes the optimization problem NP-hard. In addition, we generalize the cardinality constraint for grouped feature selection, which makes it possible to identify key sets of predictors that may be measured together in a kit in clinical practice. We demonstrate the operation of our cardinality constraint-based feature subset selection method, named OSCAR, in the context of prognostic prediction of prostate cancer patients, where it enables one to determine the key explanatory predictors at different levels of model sparsity. We further explore how the model sparsity affects the model accuracy and implementation cost. Lastly, we demonstrate generalization of the presented methodology to high-dimensional transcriptomics data.

[Essential trace elements, vitamins, and selected electrolytes in complementary medicine for cancer patients]

OBJECTIVE

Are there any evidence-based medicine (EBM)-supported treatment approaches of complementary and alternative medicine (CAM) methods for urological oncologists?

METHODS

We reviewed the actual German S3 guidelines "Supportive Care" and "Complementary Medicine" as well as the online-tool Onkopedia for recommendations about essential trace elements (Zn, Se, Mn, Fe), vitamins (A, B, C, D, E), and electrolytes (Mg, Ca). Furthermore, we added results of randomized trials to present potential future developments.

RESULTS

Each therapy with micronutrients should be based on laboratory observation of a deficit. There are selected guideline recommendations for selenium, iron and vitamin D. Potential indications were registered for manganese, vitamin A derivates, and vitamin C. No benefit was observed for vitamin B, zinc, and vitamin E.

CONCLUSION

Micronutrients should be substituted in the case of deficit. General supplementation of daily nutrition is not recommended for cancer patients.

Metabolic syndrome, obesity and cancer risk

PURPOSE OF REVIEW

This review aims to report the latest discoveries regarding the relationship between BMI, obesity, and cancer development and treatment.

RECENT FINDINGS

Obesity and metabolic syndrome relationships with cancer have been deeply investigated in the literature but their association is still debated. Currently, it has been recorded an association between BMI and endometrial, colorectal, gastric, liver, bladder, and prostate cancer. The mechanisms behind this association have also been investigated. It has been hypothesized that chronic inflammation determined by obesity may concur to the development of tumors and that Insulin Resistance may enhance cell proliferation directly or indirectly. Moreover, different studies suggest that the relationship between higher BMI and cancer may include metabolic disturbances comparable to those linked to metabolic syndrome. However, greater weight has been linked to a better overall prognosis in patients with advanced disease, a concept called the obesity paradox. This paradox has been recently investigated in the context of urological malignancies, such as bladder, prostate, and kidney cancer.

SUMMARY

Patients' metabolic and morphological status may impact their risk of developing different types of tumors and the response to systemic therapy. However, further research is necessary to better delineate the mechanisms behind these associations and how they could or should affect medical decision.

A novel prognostic model predicting overall survival in patients with metastatic castration-resistant prostate cancer receiving standard chemotherapy: A multi-trial cohort analysis

PURPOSE

Generalizable, updated, and easy-to-use prognostic models for patients with metastatic castration-resistant prostate cancer (mCRPC) are lacking. We developed a nomogram predicting the overall survival (OS) of mCRPC patients receiving standard chemotherapy using data from five randomized clinical trials (RCTs).

METHODS

Patients enrolled in the control arm of five RCTs (ASCENT 2, VENICE, CELGENE/MAINSAIL, ENTHUSE 14, and ENTHUSE 33) were randomly split between training (n = 1636, 70%) and validation cohorts (n = 700, 30%). In the training cohort, Cox regression tested the prognostic significance of all available variables as a predictor of OS. Independent predictors of OS on multivariable analysis were used to construct a novel multivariable model (nomogram). The accuracy of this model was tested in the validation cohort using time-dependent area under the curve (tAUC) and calibration curves.

RESULTS

Most of the patients were aged 65-74 years (44.5%) and the median (interquartile range) follow-up time was 13.9 (8.9-20.2) months. At multivariable analysis, the following were independent predictors of OS in mCRPC patients: sites of metastasis (visceral vs. bone metastasis, hazard ratio [HR]: 1.24), prostate-specific antigen (HR: 1.00), aspartate transaminase (HR: 1.01), alkaline phosphatase (HR: 1.00), body mass index (HR: 0.97), and hemoglobin (≥13 g/dl vs. <11 g/dl, HR: 0.41; all p < 0.05). A nomogram based on these variables was developed and showed favorable discrimination (tAUC at 12 and 24 months: 73% and 72%, respectively) and calibration characteristics on external validation.

CONCLUSION

A new prognostic model to predict OS of patients with mCRPC undergoing first line chemotherapy was developed. This can help urologists/oncologists in counseling patients and might be useful to better stratify patients for future clinical trials.

Consideration of possible effects of vitamin D on established cancer, with reference to malignant melanoma

Epidemiological studies indicate that Vitamin D has a beneficial, inhibitory effect on cancer development and subsequent progression, including melanoma (MM), and favourable MM outcome has been reported as directly related to vitamin D3 status, assessed by serum 25-hydroxyvitamin D3 (25[OH]D3 ) levels taken at diagnosis. It has been recommended that MM patients with deficient levels of 25(OH)D3 be given vitamin D3 . We examine possible beneficial or detrimental effects of treating established cancer with vitamin D3 . We consider the likely biological determinants of cancer outcome, the reported effects of vitamin D3 on these in both cancerous and non-cancerous settings, and how the effect of vitamin D3 might change depending on the integrity of tumour vitamin D receptor (VDR) signalling. We would argue that the effect of defective tumour VDR signalling could result in loss of suppression of growth, reduction of anti-tumour immunity, with potential antagonism of the elimination phase and enhancement of the escape phase of tumour immunoediting, possibly increased angiogenesis but continued suppression of inflammation. In animal models, having defective VDR signalling, vitamin D3 administration decreased survival and increased metastases. Comparable studies in man are lacking but in advanced disease, a likely marker of defective VDR signalling, studies have shown modest or no improvement in outcome with some evidence of worsening. Work is needed in assessing the integrity of tumour VDR signalling and the safety of vitamin D3 supplementation when defective.

A phase II study of docetaxel plus lycopene in metastatic castrate resistant prostate cancer

We carried out a phase II study to investigate the activity of docetaxel plus lycopene in advanced castrate resistant adenocarcinoma of the prostate. Patients were chemotherapy and biological therapy naive. Docetaxel 75 mg/m² was given every 21 days with daily oral lycopene 30 mg. The primary endpoint was a ≥50% reduction in PSA. Secondary endpoints were median time to PSA progression, duration of response and overall survival. Thirteen patients were initiated on protocol therapy. Median age was 77 (range 55-90). Twelve patients (92%) had bone metastases. Four patients (30%) had both bone and visceral metastases. PSA response was seen in 10 patients (76.9% [95% confidence interval (CI), 46.2-94.9%]). Two patients had stable disease (SD), yielding a disease control rate of 92%. Median time to PSA progression was 8 months [95% CI, 3.5-8.7]. Median duration of response (DOR) was 7.3 months [95% CI, 4.8-13.2]. Median overall survival at 5 years was 35.1 months [95% CI 25.7-57.7]. No new safety signals were noted. No patients experienced grade 3 or above anemia. One patient (7%) experienced febrile neutropenia. A PSA response rate of 76.9% and median survival of 35.1 months compares favorably to the 45% PSA response rate and 17.4 months median survival reported for the TAX 237 trialists. While our study was limited due to small sample size, our results suggest that the combination of docetaxel and lycopene merits further study.

Clinical Practice Guideline: Complementary Medicine in the Treatment of Cancer Patients

BACKGROUND

Approximately half of all patients with cancer use at least one method of complementary medicine during or after tumor treatment. The substances most commonly taken are micronutrients, food supplements, and plant extracts.

METHODS

This guideline is based on pertinent articles retrieved by a systematic search in the Medline, Cochrane Library, Embase, PsycInfo, and Cinahl databases.

RESULTS

The evidence is offen scant for any effect of a complementary method on patientrelevant endpoints such as relief of disease symptoms, reduction of treatment side effects, or prolonged survival. Micronutrients are available in different compositions, and their dosages vary. In most studies on the use of vitamins and trace elements by cancer patients, the blood level of the substance in question was not measured before its administration, so that it remains unknown whether a deficiency was present. For this reason, no well-founded conclusion on the effects of these substances can be drawn, and their use cannot be recommended in most cases. On the other hand, there is high-level evidence supporting physical exercise by cancer patients during and after their treatment. For patients with any type of cancer, mortality is lower among those who perform more physical exercise, whether before or after they receive the diagnosis of cancer (exercise before diagnosis, hazard ratio [HR] 0.82, 95% confidence interval [CI] [0.79; 0.86]; exercise after diagnosis, HR 0.63, 95% CI [0.53; 0.75]). Physical exercise during and after treatment for cancer should, therefore, be recommended to all cancer patients.

CONCLUSION

The inherent positive attribute of complementary medicine is patient empowerment: it enables patients to help themselves in an active way even while undergoing cancer treatment, as well as afterward. To avoid risks to health, patients should be instructed about unsafe methods, asked repeatedly about their use of complementary medicine, and informed specifically about potential interactions between such interventions and their cancer treatment.

Vitamin D Supplementation and Cancer Mortality: Narrative Review of Observational Studies and Clinical Trials

Several studies have investigated the beneficial effects of vitamin D on survival of cancer patients. Overall evidence has been accumulating with contrasting results. This paper aims at narratively reviewing the existing articles examining the link between vitamin D supplementation and cancer mortality. We performed two distinct searches to identify observational (ObS) studies and randomized clinical trials (RCTs) of vitamin D supplementation (VDS) in cancer patients and cohorts of general population, which included cancer mortality as an outcome. Published reports were gathered until March 2021. We identified 25 papers published between 2003 and 2020, including n. 8 RCTs on cancer patients, n. 8 population RCTs and n. 9 ObS studies. There was some evidence that the use of VDS in cancer patients could improve cancer survival, but no significant effect was found in population RCTs. Some ObS studies reported evidence that VDS was associated with a longer survival among cancer patients, and only one study found an opposite effect. The findings do not allow conclusive answers. VDS may have the potential as treatment to improve survival in cancer patients, but further investigations are warranted. We strongly support investment in well-designed and sufficiently powered RCTs to fully evaluate this association.

Inhibition of Janus Kinase 1 synergizes docetaxel sensitivity in prostate cancer cells

Prostate cancer (PCa) is the second most common malignancy and is the fifth leading cause of cancer mortality among men globally. Docetaxel-based therapy remains the first-line treatment for metastatic castration-resistant prostate cancer. However, dose-limiting toxicity including neutropenia, myelosuppression and neurotoxicity is the major reason for docetaxel dose reductions and fewer cycles administered, despite a recent study showing a clear survival benefit with increased total number of docetaxel cycles in PCa patients. Although previous studies have attempted to improve the efficacy and reduce docetaxel toxicity through drug combination, no drug has yet demonstrated improved overall survival in clinical trial, highlighting the challenges of improving the activity of docetaxel monotherapy in PCa. Herein, we identified 15 lethality hits for which inhibition could enhance docetaxel sensitivity in PCa cells via a high-throughput kinome-wide loss-of-function screen. Further drug-gene interactions analyses identified Janus kinase 1 (JAK1) as a viable druggable target with existing experimental inhibitors and FDA-approved drugs. We demonstrated that depletion of endogenous JAK1 enhanced docetaxel-induced apoptosis in PCa cells. Furthermore, inhibition of JAK1/2 by baricitinib and ruxolitinib synergizes docetaxel sensitivity in both androgen receptor (AR)-negative DU145 and PC3 cells, but not in the AR-positive LNCaP cells. In contrast, no synergistic effects were observed in cells treated with JAK2-specific inhibitor, fedratinib, suggesting that the synergistic effects are mainly mediated through JAK1 inhibition. In conclusion, the combination therapy with JAK1 inhibitors and docetaxel could be a useful therapeutic strategy in the treatment of prostate cancers.

Predicting toxicity-related docetaxel discontinuation and overall survival in metastatic castration-resistant prostate cancer: a pooled analysis of open phase 3 clinical trial data

BACKGROUND

Docetaxel is widely used in metastatic castration-resistant prostate cancer (mCRPC), however its optimal use remains unclear in the current treatment landscape. Biomarkers to predict Docetaxel toxicity may help optimize treatment selection. We aimed to create a predictive model for toxicity-related Docetaxel discontinuation (TRDD).

METHODS

Through Project Data Sphere, we accessed individual patient data from the control arms of three frontline mCRPC trials: ASCENT2, VENICE, and MAINSAIL. The inclusion criteria for these trials were all similar and included patients with chemotherapy-naïve mCRPC. The primary outcome was occurrence of TRDD. A competing risks regression (CRR) was used to predict TRDD, after accounting for the occurrence of competing events (death or progression). The output of the model was used as the dependent variable on a classification and regression tree (CART) to identify risk groups for TRDD.

RESULTS

Overall, 1568 patients were considered. Pooled CI of TRDD was 19% after accounting for competing events (death: 474; progression: 59) within 12 months of starting treatment. To build a risk calculator we relied on a CRR that ultimately included age, ECOG performance status, AST, bilirubin, use of analgesics, and presence of diabetes and chronic kidney disease. The CART analysis identified three risk groups that were named: low (model-derived TRDD risk ≤24%), intermediate (25-64%), and high (≥65%) risk group. In each risk group, probability of TRDD during treatment was 14%, 58%, and 79%, and median OS was 24 months, 20 months, and 13 months, respectively (p < 0.001).

CONCLUSIONS

Treatment selection in mCRPC remains a challenge. Our model can help clinicians balance Docetaxel toxicity and efficacy. The three risk categories that we identified correlated with OS and this is particularly useful for an optimal shared decision-making process.

The obesity paradox in metastatic castration-resistant prostate cancer

OBJECTIVE

To test whether body mass index (BMI) amongst patients with metastatic castration-resistant prostate cancer (mCRPC) is associated with overall survival (OS) and cancer-specific survival.

METHODS

Individual patient data from 1577 men with mCRPC treated with docetaxel and prednisone from the control arms of ASCENT2, VENICE, and MAINSAIL were considered. The role of BMI on survival outcomes was investigated both as a continuous and categorical variable (≤24.9 vs. 25-29.9 vs. ≥30 km/m²). BMI ≥ 30 kg/m² was considered obese. Analyses were adjusted for age, PSA, ECOG performance status, number of metastases and prior treatment. The Cox semi-proportional hazard model was used to predict OS, whereas competing risks regression was used for predicting cancer-specific mortality (CSM). To exclude any possible effect attributable to higher doses of chemotherapy (titrated according to body-surface area), we checked for eventual interactions between BMI and chemotherapy dose (both as continuous-continuous and categorical-continuous interactions).

RESULTS

The median (IQR) age for the patient population was 69 (63,74) years with a median (IQR) BMI of 28 (25-31) kg/m². Median follow-up for survivors was 12 months. Of the 1577 patients included, 655 were deceased by the end of the studies. Regarding OS, BMI emerged as a protective factor both as a continuous variable (HR: 0.96; 95% CI: 0.94, 0.99; p = 0.015) and as a categorical variable (obesity: HR: 0.71, 95% CI: 0.53, 0.96; p = 0.027, relatively to normal weight). The protective effect of high BMI on CSM was confirmed both as a continuous (SHR: 0.94; 95% CI: 0.91, 0.98; p = 0.002) and as a categorical variable (obesity SHR: 0.65; 95% CI: 0.45, 0.93; p = 0.018). No interaction was detected between the BMI categories and the docetaxel dose at any level in our analyses (all p » 0.05).

CONCLUSIONS

Obese patients with mCRPC had better cancer-specific and overall survival as compared to overweight and normal weight patients. The protective effect of BMI was not related to receiving higher chemotherapy doses. Further studies aimed at elucidating the biological mechanism behind this effect are warranted.

KEYNOTE-921: Phase III study of pembrolizumab plus docetaxel for metastatic castration-resistant prostate cancer

Despite recent advances, treatment options for men with metastatic castration-resistant prostate cancer (mCRPC) progressing after next-generation hormonal agents (NHAs) are limited and provide only modest survival benefit. Thus, an unmet need remains for mCRPC patients after treatment with targeted endocrine therapy or NHA therapy. Pembrolizumab, a humanized monoclonal antibody for PD-1, has been found to have activity as monotherapy in patients with mCRPC and as combination therapy in a Phase Ib/II study with docetaxel and prednisone/prednisolone for patients previously treated with enzalutamide or abiraterone acetate. The aim of the randomized, double-blind, Phase III KEYNOTE-921 study is to evaluate the efficacy and safety of pembrolizumab plus docetaxel in patients with mCRPC who were previously treated with an NHA. Clinical trial registration: NCT03834506 (ClinicalTrials.gov).

1α,25-Dihydroxyvitamin D3 synergistically enhances anticancer effects of ginsenoside Rh2 in human prostate cancer cells

1α,25-dihydroxyvitamin D₃ (1,25(OH)₂D₃, commonly known as calcitriol), the most active metabolite of vitamin D₃, and ginsenoside Rh2 can regulate cellular differentiation and proliferation proteins. The purpose of the present study was to assess the effect of 1,25(OH)₂D₃ on the anticancer activities of Rh2 in human prostate cancer cells such as androgen-dependent LNCaP and androgen-independent C4-2 in vitro. The effects of treatment with 1,25(OH)₂D₃ or Rh2, either alone or in combination, on prostate cancer cells were evaluated through tetrazolium-based cell viability assay, BrdU cell proliferation rate estimation assay, and Western blot protein expression analyses of nuclear receptors (androgen receptor and vitamin D receptors) and apoptotic proteins (Bcl-2, Bax, and Caspase 3). The Combination Indices (CI) and Dose Reduction Indices (DRI) of 1,25(OH)₂D₃ and Rh2 were calculated to determine synergistic anticancer activity using Calcusyn software (Biosoft, Cambridge, UK). The cell viability assay data indicate that Rh2 treatment alone inhibited cell viability in a concentration-dependent manner and the addition of 10 nM 1,25(OH)₂D₃ to Rh2 significantly enhanced its ability to reduce cell viability up to 80 % in both the cell lines. Similarly, addition of 10 nM 1,25(OH)₂D₃ to Rh2 significantly lowered its IC₅₀ values for cell proliferation from the range of 32-65 μM to 14-8 μM in LNCaP and C4-2 cells. In addition, protein expression analyses indicated that the combined treatment with Rh2 and 1,25(OH)₂D₃ led to greater downregulation of androgen receptor expression compared to single agent exposure. Similarly, the presence of 1,25(OH)₂D₃ synergistically increased the pro-apoptotic actions of Rh2 in both the cell lines. Overall, 1,25(OH)₂D₃ augments the Rh2-mediated anticancer effects through stimulating apoptosis and reduced cell proliferation which suggests that synergism of this combination may lead to potential lower need of the active vitamin D₃ and limited toxicity from it.

Drug resistant cells with very large proliferative potential grow exponentially in metastatic prostate cancer

Most metastatic cancers develop drug resistance during treatment and continue to grow, driven by a subpopulation of cancer cells unresponsive to the therapy being administered. There is evidence that metastases are formed by phenotypically plastic cancer cells with stem-cell like properties. Currently the population structure and growth dynamics of the resulting metastatic tumors is unknown. Here, using scaling analysis of clinical data of tumor burden in patients with metastatic prostate cancer, we show that the drug resistant, metastasis-causing cells (MCC) are capable of producing drug resistant, exponentially growing tumors, responsible for tumor growth as a patient receives different treatments.

Report and Abstracts of the 17th Meeting of IIM, the Interuniversity Institute of Myology:Virtual meeting, October 16-18, 2020

In 2020, due to the COVID-19 pandemic, the annual meeting of the Interuniversity Institute of Myology (IIM), took place on a virtual platform. Attendees were scientists and clinicians, as well as pharmaceutical companies and patient organization representatives from Italy, several European countries, Canada and USA. Four internationally renowned Keynote speakers presented recent advances on muscle stem cells regulation, skeletal muscle regeneration, quantitative biology approaches, and metabolic regulation of muscle homeostasis. Novel, unpublished data by young trainees were presented as oral communications or posters, in five scientific sessions and two poster sessions. On October 15, 2020, selected young trainees participated to the High Training Course on "Advanced Myology", organized together with the University of Perugia, Italy. The course, on a virtual platform, showcased lectures on muscle development and regulation of muscle gene expression by international speakers, and roundtables discussions on "Single cell analysis of skeletal muscle" and "Skeletal muscle stem cell in healthy muscle and disease". The Young IIM Committee, composed by young trainee winners of awards in the past IIM Meeting editions, was directly involved in the selection of keynote speakers, the organization of scientific sessions and roundtables discussions tailored to the interests of their peers. A broad audience of Italian, European and North American participants contributed to the different initiatives. The meeting was characterized by a friendly and inclusive atmosphere, facilitating lively and stimulating discussions on emerging areas of muscle research. The meeting stimulated scientific cross-fertilization fostering novel ideas and scientific collaborations aimed at better understanding muscle normal physiology and the mechanisms underlaying muscle diseases, with the ultimate goal of developing better therapeutic strategies. The meeting was a success, and the number of meeting attendees was the highest of all IIM Meeting editions. Despite the current difficulties imposed by the COVID-19 pandemic, we are confident that the IIM community will continue to grow and deliver significant contributions to the understanding of muscle development and function, the pathogenesis of muscular diseases and the development of novel therapeutic approaches. Here, abstracts of the meeting illustrate the new results on basic, translational, and clinical research, confirming that our field is strong and healthy.

Vitamin D Signaling in Inflammation and Cancer: Molecular Mechanisms and Therapeutic Implications

Vitamin D and its active metabolites are important nutrients for human skeletal health. UV irradiation of skin converts 7-dehydrocholesterol into vitamin D3, which metabolized in the liver and kidneys into its active form, 1α,25-dihydroxyvitamin D3. Apart from its classical role in calcium and phosphate regulation, scientists have shown that the vitamin D receptor is expressed in almost all tissues of the body, hence it has numerous biological effects. These includes fetal and adult homeostatic functions in development and differentiation of metabolic, epidermal, endocrine, neurological and immunological systems of the body. Moreover, the expression of vitamin D receptor in the majority of immune cells and the ability of these cells to actively metabolize 25(OH)D3 into its active form 1,25(OH)₂D3 reinforces the important role of vitamin D signaling in maintaining a healthy immune system. In addition, several studies have showed that vitamin D has important regulatory roles of mechanisms controlling proliferation, differentiation and growth. The administration of vitamin D analogues or the active metabolite of vitamin D activates apoptotic pathways, has antiproliferative effects and inhibits angiogenesis. This review aims to provide an up-to-date overview on the effects of vitamin D and its receptor (VDR) in regulating inflammation, different cell death modalities and cancer. It also aims to investigate the possible therapeutic benefits of vitamin D and its analogues as anticancer agents.

Vitamin D-Induced Molecular Mechanisms to Potentiate Cancer Therapy and to Reverse Drug-Resistance in Cancer Cells

Increasing interest in studying the role of vitamin D in cancer has been provided by the scientific literature during the last years, although mixed results have been reported. Vitamin D deficiency has been largely associated with various types of solid and non-solid human cancers, and the almost ubiquitous expression of vitamin D receptor (VDR) has always led to suppose a crucial role of vitamin D in cancer. However, the association between vitamin D levels and the risk of solid cancers, such as colorectal, prostate and breast cancer, shows several conflicting results that raise questions about the use of vitamin D supplements in cancer patients. Moreover, studies on vitamin D supplementation do not always show improvements in tumor progression and mortality risk, particularly for prostate and breast cancer. Conversely, several molecular studies are in agreement about the role of vitamin D in inhibiting tumor cell proliferation, growth and invasiveness, cell cycle arrest and inflammatory signaling, through which vitamin D may also regulate cancer microenvironment through the activation of different molecular pathways. More recently, a role in the regulation of cancer stem cells proliferation and short non-coding microRNA (miRNAs) expression has emerged, conferring to vitamin D a more crucial role in cancer development and progression. Interestingly, it has been shown that vitamin D is able not only to potentiate the effects of traditional cancer therapy but can even contribute to overcome the molecular mechanisms of drug resistance—often triggering tumor-spreading. At this regard, vitamin D can act at various levels through the regulation of growth of cancer stem cells and the epithelial–mesenchymal transition (EMT), as well as through the modulation of miRNA gene expression. The current review reconsiders epidemiological and molecular literature concerning the role of vitamin D in cancer risk and tumor development and progression, as well as the action of vitamin D supplementation in potentiating the effects of drug therapy and overcoming the mechanisms of resistance often triggered during cancer therapies, by critically addressing strengths and weaknesses of available data from 2010 to 2020.

Comparative Survival of Asian and White Metastatic Castration-Resistant Prostate Cancer Men Treated With Docetaxel

There are few data regarding disparities in overall survival (OS) between Asian and white men with metastatic castration-resistant prostate cancer (mCRPC). We compared OS of Asian and white mCRPC men treated in phase III clinical trials with docetaxel and prednisone (DP) or a DP-containing regimen. Individual participant data from 8820 men with mCRPC randomly assigned on nine phase III trials to receive DP or a DP-containing regimen were combined. Men enrolled in these trials had a diagnosis of prostate adenocarcinoma. The median overall survival was 18.8 months (95% confidence interval [CI] = 17.4 to 22.1 months) and 21.2 months (95% CI = 20.8 to 21.7 months) for Asian and white men, respectively. The pooled hazard ratio for death for Asian men compared with white men, adjusted for baseline prognostic factors, was 0.95 (95% CI = 0.84 to 1.09), indicating that Asian men were not at increased risk of death. This large analysis showed that Asian men did not have shorter OS duration than white men treated with docetaxel.

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

BACKGROUND

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

PATIENTS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

Effects of vitamin D on drugs: Response and disposal

Vitamin D supplementation and vitamin D deficiency are common in clinical experience and in daily life. Vitamin D not only promotes calcium absorption and immune regulation, but also changes drug effects (pharmacodynamics and adverse reactions) and drug disposal in vivo when combined with various commonly used clinical drugs. The extensive physiological effects of vitamin D may cause synergism effects or alleviation of adverse reactions, and vitamin D's affect on drugs in vivo disposal through drug transporters or metabolic enzymes may also lead to changes in drug effects. Herein, the effects of vitamin D combined with commonly used drugs were reviewed from the perspective of drug efficacy and adverse reactions. The effects of vitamin D on drug transport and metabolism were summarized and analyzed. Hopefully, more attention will be paid to vitamin D supplementation and deficiency in clinical treatment and drug research and development.

Cost-effective survival prediction for patients with advanced prostate cancer using clinical trial and real-world hospital registry datasets

INTRODUCTION

Predictive survival modeling offers systematic tools for clinical decision-making and individualized tailoring of treatment strategies to improve patient outcomes while reducing overall healthcare costs. In 2015, a number of machine learning and statistical models were benchmarked in the DREAM 9.5 Prostate Cancer Challenge, based on open clinical trial data for metastatic castration resistant prostate cancer (mCRPC). However, applying these models into clinical practice poses a practical challenge due to the inclusion of a large number of model variables, some of which are not routinely monitored or are expensive to measure.

OBJECTIVES

To develop cost-specified variable selection algorithms for constructing cost-effective prognostic models of overall survival that still preserve sufficient model performance for clinical decision making.

METHODS

Penalized Cox regression models were used for the survival prediction. For the variable selection, we implemented two algorithms: (i) LASSO regularization approach; and (ii) a greedy cost-specified variable selection algorithm. The models were compared in three cohorts of mCRPC patients from randomized clinical trials (RCT), as well as in a real-world cohort (RWC) of advanced prostate cancer patients treated at the Turku University Hospital. Hospital laboratory expenses were utilized as a reference for computing the costs of introducing new variables into the models.

RESULTS

Compared to measuring the full set of clinical variables, economic costs could be reduced by half without a significant loss of model performance. The greedy algorithm outperformed the LASSO-based variable selection with the lowest tested budgets. The overall top performance was higher with the LASSO algorithm.

CONCLUSION

The cost-specified variable selection offers significant budget optimization capability for the real-world survival prediction without compromising the predictive power of the model.

Efficacy and toxicity outcomes of elderly castrate-resistant prostate cancer patients treated with docetaxel-A pooled analysis of 3 randomized studies

BACKGROUND

The current study aims to assess the differences in efficacy and toxicity outcomes according to age among metastatic castrate-resistant prostate cancer patients within a pooled cohort of 3 trials.

METHODS

This study is a pooled analysis of the control arms of 3 prospective studies (NCT00273338; NCT00988208; NCT00519285) which assessed docetaxel/prednisone among patients with metastatic castrate-resistant prostate cancer. Incidence of toxicities between the 2 age groups (<75 years vs. ≥75 years) was assessed through chi-squared testing. Through Kaplan-Meier survival estimates, overall survival was compared between the 2 age groups (<75 years vs. ≥75 years). Multivariate Cox regression analysis was then conducted to evaluate factors potentially affecting overall survival.

RESULTS

A total of 1,212 patients were <75 years old and 388 patients were ≥75 years old were included in the pooled analysis. Comparing both patient subgroups together, older patients were more likely to have any high-grade adverse event (P < 0.001), any fatal adverse events (P = 0.007), any-grade anemia (P < 0.001), and any-grade neutropenia (P < 0.001). Using Kaplan-Meier survival estimates, there was no difference in overall survival between both age groups (P = 0.084). Multivariable Cox regression analysis was additionally conducted to further assess the impact of age on overall survival. There was no difference in overall survival according to age (hazard ratio for age < 75 years vs. age ≥ 75 years: 0.883; 0.738-1.057; P = 0.176).

CONCLUSION

Older patients (≥75 years) have apparently similar survival outcomes compared to younger patients (<75 years). On the other hand, older patients have a higher risk of high-grade toxicities and fatal toxicities compared to younger patients.

A DREAM Challenge to Build Prediction Models for Short-Term Discontinuation of Docetaxel in Metastatic Castration-Resistant Prostate Cancer

Purpose

Docetaxel has a demonstrated survival benefit for patients with metastatic castration-resistant prostate cancer (mCRPC); however, 10% to 20% of patients discontinue docetaxel prematurely because of toxicity-induced adverse events, and the management of risk factors for toxicity remains a challenge.

Patients and Methods

The comparator arms of four phase III clinical trials in first-line mCRPC were collected, annotated, and compiled, with a total of 2,070 patients. Early discontinuation was defined as treatment stoppage within 3 months as a result of adverse treatment effects; 10% of patients discontinued treatment. We designed an open-data, crowd-sourced DREAM Challenge for developing models with which to predict early discontinuation of docetaxel treatment. Clinical features for all four trials and outcomes for three of the four trials were made publicly available, with the outcomes of the fourth trial held back for unbiased model evaluation. Challenge participants from around the world trained models and submitted their predictions. Area under the precision-recall curve was the primary metric used for performance assessment.

Results

In total, 34 separate teams submitted predictions. Seven models with statistically similar area under precision-recall curves (Bayes factor ≤ 3) outperformed all other models. A postchallenge analysis of risk prediction using these seven models revealed three patient subgroups: high risk, low risk, or discordant risk. Early discontinuation events were two times higher in the high-risk subgroup compared with the low-risk subgroup. Simulation studies demonstrated that use of patient discontinuation prediction models could reduce patient enrollment in clinical trials without the loss of statistical power.

Conclusion

This work represents a successful collaboration between 34 international teams that leveraged open clinical trial data. Our results demonstrate that routinely collected clinical features can be used to identify patients with mCRPC who are likely to discontinue treatment because of adverse events and establishes a robust benchmark with implications for clinical trial design.

Opposing effects of 25-hydroxy- and 1α,25-dihydroxy-vitamin D3 on pro-cachectic cytokine-and cancer conditioned medium-induced atrophy in C2C12 myotubes

AIM

Loss of skeletal muscle is one of the main features of cancer cachexia. Vitamin D (VD) deficiency is associated with impairment of muscle mass and performance and is highly prevalent in cachectic patients; therefore, VD supplementation has been proposed to counteract cancer cachexia-associated muscle loss. However, in both cachectic cancer patients and tumour-bearing animals, VD supplementation led to disappointing results, urging the need for a better understanding of VD activity on skeletal muscle.

METHODS

Cancer-associated muscle wasting was reproduced in vitro by treating C2C12 myotubes with cancer cell conditioned medium, a combination of TNF-α and IFNγ or IL-6 pro-cachectic cytokines. The biological effects and mechanisms of action of 1,25-dihydroxy VD (1,25 VD) and its precursor 25-hydroxy VD (25 VD) on myotubes were explored.

RESULTS

We demonstrated that only 25 VD was able to protect from atrophy by activating Akt signalling, inducing protein synthesis, and stimulating the autophagic flux, while 1,25 VD had an atrophic activity per se, increasing FoxO3 levels, inducing the expression of atrogenes, and blocking the autophagic flux. Furthermore, we showed that the contrasting activities of these VD metabolites on C2C12 myotubes depend on a differential induction of VD-24-hydroxylase and transformation of VD metabolites in pro-atrophic 24-hydroxylated products, as silencing of VD-24-hydroxylase reduced the atrophic activity of 1,25 VD.

CONCLUSIONS

Altogether these data might explain the lack of efficacy of VD treatment in vivo for the protection of muscle mass in cancer.

Association among plasma 1,25(OH)2 D, ratio of 1,25(OH)2 D to 25(OH)D, and prostate cancer aggressiveness

BACKGROUND

African-American (AA) men tend to present with more aggressive prostate cancer (Gleason score >7) than European-American (EA) men. Vitamin D and its metabolites are implicated in prostate cancer biology with vitamin D deficiency, indicated by its metabolite levels in serum or plasma, usually observed in AA men.

OBJECTIVE

To determine if 1, 25-dihydroxy vitamin D3 [1,25(OH)2 D] plasma levels in AA and EA prostate cancer patients alter the risk of having aggressive prostate cancer.

DESIGN

Research subjects from the North Carolina-Louisiana Prostate Cancer Project (AA n = 435 and EA n = 532) were included. Plasma metabolites 1,25(OH)2 D and 25-hydroxyvitamin D3 [25(OH)D] were measured using liquid chromatography with tandem mass spectrophotometry. Research subjects were classified into low (Gleason sum < 7, stage T1-T2, and Prostate-specific antigen (PSA) < 9 ng/mL) or high (Gleason sum > 8 or Gleason sum = 7 with 4 + 3, or PSA > 20 ng/mL, or Gleason sum = 7 and stage T3-T4) aggressive disease.

RESULTS

Research subjects in the second and third tertiles of plasma levels of 1, 25(OH)2 D had lower odds of high aggressive prostate cancer (AA [ORT2vsT1 : 0.66, 95%CI: 0.39-1.12; ORT3vsT1 : 0.83, 95%CI: 0.49-1.41] and EA [ORT2vsT1 : 0.68, 95%CI: 0.41-1.11; ORT3vsT1 : 0.67, 95%CI: 0.40-1.11]) compared with the first tertile, though confidence intervals included the null. Greater 1,25(OH)2 D/25(OH)D molar ratios were associated with lower odds of high aggressive prostate cancer more evidently in AA (ORQ4vsQ1 : 0.45, CI: 0.24-0.82) than in EA (ORQ4vsQ1 : 0.64, CI: 0.35-1.17) research subjects.

CONCLUSIONS

The 1,25(OH)2 D/25(OH)D molar ratio was associated with decreased risk of high aggressive prostate cancer in AA men, and possibly in EA men. Further studies analyzing vitamin D polymorphisms, vitamin D binding protein levels, and prostatic levels of these metabolites may be useful. These studies may provide a better understanding of the vitamin D pathway and its biological role underlying health disparities in prostate cancer.

The Role of Nuclear Receptors in Prostate Cancer

The nuclear receptor (NR) superfamily consists of 48 members that are divided into seven subfamilies. NRs are transcription factors that play an important role in a number of biological processes. The NR superfamily includes androgen receptor, which is a key player in prostate cancer pathogenesis, suggesting the functional roles of other NRs in prostate cancer. The findings on the roles of NRs in prostate cancer thus far have shown that several NRs such as vitamin D receptor, estrogen receptor β, and mineralocorticoid receptor play antioncogenic roles, while other NRs such as peroxisome proliferator-activated receptor γ and estrogen receptor α as well as androgen receptor play oncogenic roles. However, the roles of other NRs in prostate cancer remain controversial or uninvestigated. Further research on the role of NRs in prostate cancer is required and may lead to the development of novel preventions and therapeutics for prostate cancer.

Vitamin D in prostate cancer

Signaling through the vitamin D receptor has been shown to be biologically active and important in a number of preclinical studies in prostate and other cancers. Epidemiologic data also indicate that vitamin D signaling may be important in the cause and prognosis of prostate and other cancers. These data indicate that perturbation of vitamin D signaling may be a target for the prevention and treatment of prostate cancer. Large studies of vitamin D supplementation will be required to determine whether these observations can be translated into prevention strategies. This paper reviews the available data in the use of vitamin D compounds in the treatment of prostate cancer. Clinical data are limited which support the use of vitamin D compounds in the management of men with prostate cancer. However, clinical trials guided by existing preclinical data are limited.

Phase II, Multicenter, Randomized Trial of Docetaxel plus Prednisone with or Without Cediranib in Men with Chemotherapy-Naive Metastatic Castrate-Resistant Prostate Cancer

Lessons Learned.

The negative results are consistent with the negative results of large phase III trials in which docetaxel plus antiangiogenic agents were used in patients with metastatic castrate‐resistant prostate cancer (mCRPC).

The negative data underscore that, despite a sound biological rationale and supportive early‐phase clinical results, adding antiangiogenic agents to docetaxel for mCRPC is a great challenge.

Background.

Inhibition of vascular endothelial growth factor (VEGF) signaling abrogates tumor‐induced angiogenesis to constrain tumor growth, and can be exploited therapeutically by using cediranib, an oral tyrosine kinase inhibitor of VEGF receptor signaling. Our preliminary phase I trial data showed that adding cediranib to docetaxel plus prednisone (DP) was safe and feasible, with early evidence for efficacy in patients with metastatic castrate‐resistant prostate cancer (mCRPC).

Methods.

This multicenter phase II trial assessed whether adding cediranib to DP improves efficacy of DP in patients with mCRPC. Chemotherapy‐naive patients with mCRPC were randomly assigned to receive either docetaxel (75 mg/m² intravenously every 3 weeks) with prednisone (5 mg twice daily) plus cediranib (30 mg once daily; the DP+C arm) or DP only (the DP arm). The primary endpoint was to compare 6‐month progression‐free survival (PFS) rate between the two arms. Secondary endpoints included 6‐month overall survival (OS), objective tumor and prostate‐specific antigen (PSA) response rates, biomarkers, and adverse events.

Results.

The 6‐month PFS rate in a total of 58 patients was only numerically higher in the DP+C arm (61%) compared with the DP arm (57%). Similarly, the 6‐month OS rate, objective tumor and PSA response rates, and biomarkers were not significantly different between the two arms. Increased baseline levels of interleukin 6 (IL‐6), however, were significantly associated with increased risk of progression. Neutropenia was the only grade 4 toxicity (38% in the DP+C arm vs. 18% in the DP arm).

Conclusion.

Combining cediranib with docetaxel + prednisone failed to demonstrate superior efficacy, compared with docetaxel + prednisone, and added toxicity. Our data do not support pursuing the combination further in patients with mCRPC.

Effect of Vitamin D Supplementation in Prostate Cancer: A Systematic Review of Randomized Control Trials

Vitamin D is important in many cellular functions including cell cycling and proliferation, differentiation, and apoptosis. Via the induction of cell cycle arrest and/or apoptosis, vitamin D inhibits normal prostatic epithelial cells growth. Review the evidence of the effect of vitamin D supplementation on prostate cancer (PC) biomarkers and patient survival and assess optimal dosage, formulation and duration. Pubmed, Medline and Ebsco Host databases were systematically searched for relevant literature. 8 Randomized Controlled Trials were included in this review. All studies, besides one, were of high methodological quality. 4 studies used calcitriol (0,5-45 μg/weekly), 2 studies have used vitamin D3 (150-1000 μg/daily) and 2 other studies have used 1α-hydroxy Vitamin D2 (10 μg/ daily or weekly). Duration of supplementation varied between 28 days up to 18.3 months. Two studies had positive effects on prostate specific antigen (PSA) (p < .05), 1 study had a significant positive effect on median survival (p < .05) and 1 study showed a significant reduction of vitamin D receptor (VDR) expression (p < .05). The remaining studies showed negative or no effect on PC characteristics, clinical outcomes and/or survival. Current evidence suggests that vitamin D supplementation in conjunction with standard of care (e.g. chemotherapy, radiation therapy) may confer clinical benefits such as a decrease in serum PSA levels and VDR expression but further research is required to ascertain these results. Calcitriol supplementation in doses ranging from 250-1000 mg for 3-8 weeks or a lower dose of 45 mg for 18.3 months, appear most beneficial regarding outcomes of PC progression and survival.

Exploiting vulnerabilities of cancer by targeting nuclear receptors of stromal cells in tumor microenvironment

The tumor microenvironment is a complex and dynamic cellular community comprising the tumor epithelium and various tumor-supporting cells such as immune cells, fibroblasts, immunosuppressive cells, adipose cells, endothelial cells, and pericytes. The interplay between the tumor microenvironment and tumor cells represents a key contributor to immune evasiveness, physiological hardiness and the local and systemic invasiveness of malignant cells. Nuclear receptors are master regulators of physiological processes and are known to play pro-/anti-oncogenic activities in tumor cells. However, the actions of nuclear receptors in tumor-supporting cells have not been widely studied. Given the excellent druggability and extensive regulatory effects of nuclear receptors, understanding their biological functionality in the tumor microenvironment is of utmost importance. Therefore, the present review aims to summarize recent evidence about the roles of nuclear receptors in tumor-supporting cells and their implications for malignant processes such as tumor proliferation, evasion of immune surveillance, angiogenesis, chemotherapeutic resistance, and metastasis. Based on findings derived mostly from cell culture studies and a few in vivo animal cancer models, the functions of VDR, PPARs, AR, ER and GR in tumor-supporting cells are relatively well-characterized. Evidence for other receptors, such as RARβ, RORγ, and FXR, is limited yet promising. Hence, the nuclear receptor signature in the tumor microenvironment may harbor prognostic value. The clinical prospects of a tumor microenvironment-oriented cancer therapy exploiting the nuclear receptors in different tumor-supporting cells are also encouraging. The major challenge, however, lies in the ability to develop a highly specific drug delivery system to facilitate precision medicine in cancer therapy.

Repurposing vitamin D for treatment of human malignancies via targeting tumor microenvironment

Tumor cells along with a small proportion of cancer stem cells exist in a stromal microenvironment consisting of vasculature, cancer-associated fibroblasts, immune cells and extracellular components. Recent epidemiological and clinical studies strongly support that vitamin D supplementation is associated with reduced cancer risk and favorable prognosis. Experimental results suggest that vitamin D not only suppresses cancer cells, but also regulates tumor microenvironment to facilitate tumor repression. In this review, we have outlined the current knowledge on epidemiological studies and clinical trials of vitamin D. Notably, we summarized and discussed the anticancer action of vitamin D in cancer cells, cancer stem cells and stroma cells in tumor microenvironment, providing a better understanding of the role of vitamin D in cancer. We presently re-propose vitamin D to be a novel and economical anticancer agent.

Overall Survival of Black and White Men With Metastatic Castration-Resistant Prostate Cancer Treated With Docetaxel

PURPOSE

Several studies have reported that among patients with localized prostate cancer, black men have a shorter overall survival (OS) time than white men, but few data exist for men with advanced prostate cancer. The primary goal of this analysis was to compare the OS in black and white men with metastatic castration-resistant prostate cancer (mCRPC) who were treated in phase III clinical trials with docetaxel plus prednisone (DP) or a DP-containing regimen.

METHODS

Individual participant data from 8,820 men with mCRPC randomly assigned in nine phase III trials to DP or a DP-containing regimen were combined. Race was based on self-report. The primary end point was OS. The Cox proportional hazards regression model was used to assess the prognostic importance of race (black v white) adjusted for established risk factors common across the trials (age, prostate-specific antigen, performance status, alkaline phosphatase, hemoglobin, and sites of metastases).

RESULTS

Of 8,820 men, 7,528 (85%) were white, 500 (6%) were black, 424 (5%) were Asian, and 368 (4%) were of unknown race. Black men were younger and had worse performance status, higher testosterone and prostate-specific antigen, and lower hemoglobin than white men. Despite these differences, the median OS was 21.0 months (95% CI, 19.4 to 22.5 months) versus 21.2 months (95% CI, 20.8 to 21.7 months) in black and white men, respectively. The pooled multivariable hazard ratio of 0.81 (95% CI, 0.72 to 0.91) demonstrates that overall, black men have a statistically significant decreased risk of death compared with white men ( P < .001).

CONCLUSION

When adjusted for known prognostic factors, we observed a statistically significant increased OS in black versus white men with mCRPC who were enrolled in these clinical trials. The mechanism for these differences is not known.

Calcitriol and Calcipotriol Modulate Transport Activity of ABC Transporters and Exhibit Selective Cytotoxicity in MRP1-overexpressing Cells

Efflux transporters P-glycoprotein (P-gp/ABCB1), multidrug resistance protein 1 (MRP1/ABCC1), and breast cancer resistance protein (BCRP/ABCG2) can affect the efficacy and toxicity of a wide variety of drugs and are implicated in multidrug resistance (MDR). Eight test compounds, recently identified from an intramolecular FRET-based high throughput screening, were characterized for their interaction with MRP1. We report that the active metabolite of vitamin D₃, calcitriol, and its analog calcipotriol are selectively cytotoxic to MRP1-overexpressing cells, besides inhibiting transport function of P-gp, MRP1, and BCRP. Calcitriol and calcipotriol consistently displayed a potent inhibitory activity on MRP1-mediated doxorubicin and calcein efflux in MRP1-overexpressing H69AR and HEK293/MRP1 cells. Vesicular transport studies confirmed a strong inhibitory effect of calcitriol and calcipotriol on MRP1-mediated uptake of tritium-labeled estradiol glucuronide and leukotriene C₄. In cytotoxicity assays, MRP1-overexpressing cells exhibited hypersensitivity toward calcitriol and calcipotriol. Such collateral sensitivity, however, was not observed in HEK293/P-gp and HEK293/BCRP cells, although the vitamin D₃ analogs inhibited calcein efflux in P-gp-overexpressing cells, and mitoxantrone efflux in BCRP-overexpressing cells. The selective cytotoxicity of calcitriol and calpotriol toward MRP1 over-expressing cells can be eliminated with MRP1 inhibitor MK571. Our data indicate a potential role of calcitriol and its analogs in targeting malignancies in which MRP1 expression is prominent and contributes to MDR.

Polymeric nanocapsules as drug carriers for sustained anticancer activity of calcitriol in breast cancer cells

Clinical use of calcitriol (1,25-dihydroxyvitamin D₃) as an anticancer agent is currently limited by the requirement of supraphysiological doses and associated hypercalcemia. Nanoencapsulation of calcitriol is a strategy to overcome these drawbacks, allowing reduced administrated doses and/or frequency, while retaining the therapeutic activity towards cancer cells. For this purpose, we investigated the impact of calcitriol encapsulation on its antiproliferative activity and optimized formulation parameters with that respect. Calcitriol-loaded polymeric nanoparticles with different polymer:oil ratios were prepared by the nanoprecipitation method. Nanoparticles had similar mean size (200 nm) and EE (85%) whereas their release profile strongly depended on formulation parameters. Antiproliferative and cytotoxic activities of formulated calcitriol were evaluated in vitro using human breast adenocarcinoma cells (MCF-7) and showed that calcitriol-induced cell growth inhibition was closely related to its release kinetics. For the most suitable formulation, a sustained cell growth inhibition was observed over 10 days compared to free form. Advantages of calcitriol encapsulation and the role of formulation parameters on its biological activity in vitro were demonstrated. Selected nanoparticle formulation is a promising calcitriol delivery system ensuring a prolonged anticancer activity that could improve its therapeutic efficiency.

Nutraceuticals in prostate cancer therapeutic strategies and their neo-adjuvant use in diverse populations

Prostate cancer (PCa) is the most frequently diagnosed malignancy and second leading cause of cancer mortality in American males. Notably, men of African descent in the United States and Caribbean have the highest PCa mortality rates compared to men with European ancestry. Although current therapeutics are quite potent and effective, disease resistance, progression to metastasis, therapy-associated toxicities and efficacy-related issues in diverse populations develop over time. Thus, non-toxic and efficacious therapeutic strategies are needed to address these major obstacles for the clinical treatment and management of PCa. In this regard, preclinical and population-based efficacy studies have shown the potential of natural non-toxic nutraceuticals as potent anti-PCa agents. Accordingly, the implementation of nutraceutical intervention and genetic testing in diverse populations might aid in the development and design of precision medicine strategies to reduce the burden of chemotherapy-associated toxicities, suppress disease resistance, and treat both localized and advanced PCa. Consequently, additional large-scale and inclusive clinical studies are required to fully assess efficacy and therapeutic limitations of these agents in PCa. This review discusses the most current clinical research on selected nutraceutical agents and their efficacy in the context of clinico-pathological outcomes and disease susceptibility in diverse PCa clinical and epidemiological studies.

Calcitriol and cancer therapy: A missed opportunity

The vitamin D receptor is expressed in most tissues of the body - and the cancers that arise from those tissues. The vitamin D signaling pathway is active in those tissues and cancers. This is at least consistent with the hypothesis that perturbing this signaling may have a favorable effect on the genesis and growth of cancers. Epidemiologic data indicate that vitamin D signaling may be important in the initiation and outcome of a number of types of cancer. Many studies have shown that calcitriol (1,25 dihydroxycholecalciferol) and other vitamin D compounds have antiproliferative, pro-apoptotic, anti-cell migration and antiangiogenic activity in a number of preclinical studies in many different cancer types. Unfortunately, the assessment of the activity of calcitriol or other vitamin D analogues in the treatment of cancer, as single agents or in combination with other anticancer agents has been stymied by the failure to adhere to commonly accepted principles of drug development and clinical trials conduct.

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.

Laboratory-Based Biomarkers and Liver Metastases in Metastatic Castration-Resistant Prostate Cancer

BACKGROUND

Metastatic castrate-resistant prostate cancer (mCRPC) patients with liver metastases have a poor prognosis. No large studies have investigated the clinical and biochemical parameters associated with liver metastases in this population.

MATERIALS AND METHODS

Patient data made available via Project Data Sphere were collected from 1,281 men with mCRPC who were enrolled on to three phase III clinical trials for the treatment of their disease. Multiple logistic regression was performed on eight clinical and biochemical baseline variables to test their association with the presence of liver metastases on baseline radiographic imaging. Variables of interest included prior docetaxel exposure, Eastern Cooperative Oncology Group performance status, albumin, alkaline phosphatase, alanine transaminase, aspartate transaminase (AST), hemoglobin (HGB), lactate dehydrogenase (LDH), prostate-specific antigen, and total bilirubin. Final models were compared when treating the variables as either continuous or categorized.

RESULTS

Multiple variable analysis demonstrated that an increasing serum AST or LDH or a decreasing HGB was associated with an increased probability of having documented radiographic liver metastases (p < .0001). The area under the curve for the continuous model was 0.6842 and 0.6890 for the categorical one, with the latter model containing a dichotomized AST and LDH based on the upper limit of normal and tertile ranges of HGB based on the distribution of the outcome.

CONCLUSION

Our analysis demonstrated a significant association between the presence of liver metastases and laboratory levels of AST, LDH, and HGB. These have implications for patient management. More research is needed to validate these biomarkers and prospectively determine their application in the clinical setting.

IMPLICATIONS FOR PRACTICE

The purpose of this study was to evaluate biochemical and clinical biomarkers associated with the presence of liver metastases in men diagnosed with metastatic castrate-resistant prostate cancer. The results indicate that quantitative assessments of aspartate transaminase, lactate dehydrogenase, and hemoglobin are significantly associated with an increased probability of having documented radiographic liver metastases. Analysis of these simple variables can alert clinicians to those at high risk for prostate cancer that has spread to the liver, a finding of clear importance for clinical management.

Further Developments of the Phenyl-Pyrrolyl Pentane Series of Nonsteroidal Vitamin D Receptor Modulators as Anticancer Agents

The vitamin D₃ receptor (VDR), which belongs to the nuclear-receptor superfamily, is a potential molecular target for anticancer-drug discovery. In this study, a series of nonsteroidal vitamin D mimics with phenyl-pyrrolyl pentane skeletons with therapeutic potentials in cancer treatment were synthesized. Among them, 11b and 11g were identified as the most effective agents in reducing the viability of four cancer-cell lines, particularly those of breast-cancer cells, with IC₅₀ values in the submicromolar-concentration range. In addition, 11b and 11g possessed VDR-binding affinities and displayed significant partial VDR-agonistic activities determined by dual-luciferase-reporter assays and human-leukemia-cell-line (HL-60)-differentiation assays. Furthermore, 11b and 11g inhibited tumor growth in an orthotopic breast-tumor model via inhibition of cell proliferation and induction of cell apoptosis. More importantly, 11b and 11g exhibited favorable pharmacokinetic behavior in vivo and did not increase serum calcium levels or cause any other apparent side effects. In summary, 11b and 11g act as novel VDR modulators and may be promising candidates for cancer chemotherapy.

Phase I Trial of the Combination of Docetaxel, Prednisone, and Pasireotide in Metastatic Castrate-Resistant Prostate Cancer

BACKGROUND

Pasireotide (SOM230; Novartis Inc, Basel, Switzerland) is a multitargeted somatostatin receptor analogue likely to treat the neuroendocrine, and docetaxel resistant components within metastatic castrate-resistant prostate cancer (mCRPC). This phase I trial tested the combination of pasireotide, docetaxel, and prednisone in pretreated mCRPC.

PATIENTS AND METHODS

Chemotherapy naive mCRPC patients received docetaxel 75 mg/m² intravenously every 21 days and pasireotide intramuscularly every 28 days at escalating dose levels of 40, 60, and 80 mg. Maximum tolerated dose and recommended phase II dose (RP2D) were assessed.

RESULTS

Eighteen patients were enrolled with a median age of 65 (range, 49-75) years, and pretherapy prostate-specific antigen of 259.9 ng/mL. The dose-limiting toxicities were Grade 4 hyperglycemia unresponsive to therapy and Grade 4 neutropenia lasting for > 7 days in 1 patient each occurring at the 80-mg dose level of pasireotide. The RP2D was determined at 60 mg every 28 days. Four patients at the 60 mg dose had Grade 3 or 4 hyperglycemia, which responded adequately to therapy. Median time to progression and survival were 7.2 and 18.3 months, respectively. Three of 6 patients with circulating tumor cells ≥5 converted to circulating tumor cells < 5 post therapy. The insulin like growth factor-1 levels revealed a median 51% decrease after therapy. The neuron-specific enolase and chromogranin did not show any marked change.

CONCLUSION

The addition of pasireotide to docetaxel and prednisone is clinically feasible at a dose level of 60 mg every 28 days. The combination showed potential for clinical efficacy but needs to be compared with the standard docetaxel and prednisone regimen.

Taxane-based Combination Therapies for Metastatic Prostate Cancer

CONTEXT

Multiple single-agent therapies improving survival are approved for the treatment of metastatic castration-resistant prostate cancer (mCRPC), including two chemotherapies, two androgen-signaling axis-targeting agents, an immunotherapeutic vaccine, and a radiopharmaceutical. Combination therapy can target multiple oncogenic pathways simultaneously, while potentially curbing the development of treatment resistance.

OBJECTIVE

To provide a succinct overview of taxane-based combination therapies currently being evaluated for the treatment of metastatic prostate cancer.

EVIDENCE ACQUISITION

We searched MEDLINE/PubMed^® and relevant congress databases for literature focused on taxane-based combination therapies being evaluated for the treatment of metastatic prostate cancer. In addition, a systematic search of www.clinicaltrials.gov was performed to gather information regarding ongoing taxane-based combination trials in prostate cancer. This search included phase II or III trials starting after January 1, 2010, which included the terms "docetaxel" or "cabazitaxel" and "prostate", and was then manually filtered for combination studies.

EVIDENCE SYNTHESIS

Single-agent therapy yields modest increments in survival. The success of combining docetaxel with androgen deprivation to improve overall survival (OS) for metastatic hormone-sensitive disease suggests the potential of similar approaches in mCRPC. Several classes of biological drugs have previously been combined with docetaxel for mCRPC in clinical trials without improvement in OS. However, combining docetaxel or cabazitaxel with newer agents with established single-agent benefit, such as radium-223, second-generation androgen pathway-targeted agents, or other chemotherapies, has the potential to benefit patients when compared with taxane chemotherapy alone. Our search revealed that the majority of trials currently assessing taxanes are focused on combination therapies: a combination approach is being evaluated in 37 of 47 trials assessing docetaxel and in 18 of 34 trials assessing cabazitaxel.

CONCLUSIONS

Despite prior failures, novel taxane-based combination therapies have the potential to improve outcomes in mCRPC. Challenges include the absence of validated predictive biomarkers for the selection of suitable patients and the potential for enhanced toxicity.

PATIENT SUMMARY

Patients with metastatic prostate cancer have access to multiple therapies improving survival. Many advanced epithelial cancers are treated with combinations of drugs; however, prostate cancer has remained an exception. A number of clinical studies have shown that combining chemotherapy with other classes of therapy may improve patient outcomes in prostate cancer. Here, we summarize the various combinations that are tested in the clinic and review the results.

Vitamin D Receptor Signaling and Cancer

The vitamin D receptor (VDR) binds the secosteroid hormone 1,25(OH)₂D₃ with high affinity and regulates gene programs that control a serum calcium levels, as well as cell proliferation and differentiation. A significant focus has been to exploit the VDR in cancer settings. Although preclinical studies have been strongly encouraging, to date clinical trials have delivered equivocal findings that have paused the clinical translation of these compounds. However, it is entirely possible that mining of genomic data will help to refine precisely what are the key anticancer actions of vitamin D compounds and where these can be used most effectively.