Hormonal impact of the 17alpha-hydroxylase/C(17,20)-lyase inhibitor abiraterone acetate (CB7630) in patients with prostate cancer

Kinesin Facilitates Phenotypic Targeting of Therapeutic Resistance in Advanced Prostate Cancer

Understanding the mechanisms underlying resistance is critical to improving therapeutic outcomes in patients with metastatic castration-resistant prostate cancer. Previous work showed that dynamic interconversions between epithelial-mesenchymal transition to mesenchymal-epithelial transition defines the phenotypic landscape of prostate tumors, as a potential driver of the emergence of therapeutic resistance. In this study, we use in vitro and in vivo preclinical MDA PCa patient-derived xenograft models of resistant human prostate cancer to determine molecular mechanisms of cross-resistance between antiandrogen therapy and taxane chemotherapy, underlying the therapeutically resistant phenotype. Transcriptomic profiling revealed that resistant and sensitive prostate cancer C4-2B cells have a unique differential gene signature response to cabazitaxel. Gene pathway analysis showed that sensitive cells exhibit an increase in DNA damage, while resistant cells express genes associated with protein regulation in response to cabazitaxel. The patient-derived xenograft model specimens are from patients who have metastatic lethal castration-resistant prostate cancer, treated with androgen deprivation therapy, antiandrogens, and chemotherapy including second-line taxane chemotherapy, cabazitaxel. Immunohistochemistry revealed high expression of E-cadherin and low expression of vimentin resulting in redifferentiation toward an epithelial phenotype. Furthermore, the mitotic kinesin-related protein involved in microtubule binding and the SLCO1B3 transporter (implicated in cabazitaxel intracellular transport) are associated with resistance in these prostate tumors. Combinational targeting of kinesins (ispinesib) with cabazitaxel was more effective than single monotherapies in inducing cell death in resistant prostate tumors. Implications: Our findings are of translational significance in identifying kinesin as a novel target of cross-resistance toward enhancing therapeutic vulnerability and improved clinical outcomes in patients with advanced prostate cancer.

Circulating Tumor DNA in Genitourinary Cancers: Detection, Prognostics, and Therapeutic Implications

CtDNA is emerging as a non-invasive clinical detection method for several cancers, including genitourinary (GU) cancers such as prostate cancer, bladder cancer, and renal cell carcinoma (RCC). CtDNA assays have shown promise in early detection of GU cancers, providing prognostic information, assessing real-time treatment response, and detecting residual disease and relapse. The ease of obtaining a "liquid biopsy" from blood or urine in GU cancers enhances its potential to be used as a biomarker. Interrogating these "liquid biopsies" for ctDNA can then be used to detect common cancer mutations, novel genomic alterations, or epigenetic modifications. CtDNA has undergone investigation in numerous clinical trials, which could address clinical needs in GU cancers, for instance, earlier detection in RCC, therapeutic response prediction in castration-resistant prostate cancer, and monitoring for recurrence in bladder cancers. The utilization of liquid biopsy for ctDNA analysis provides a promising method of advancing precision medicine within the field of GU cancers.

New-generation androgen receptor signaling inhibitors (ARSIs) in metastatic hormone-sensitive prostate cancer (mHSPC): pharmacokinetics, drug-drug interactions (DDIs), and clinical impact

INTRODUCTION

The therapeutic scenario of metastatic hormone-sensitive prostate cancer (mHSPC) has dramatically changed in recent years, with the approval of new-generation Androgen Receptor Signaling Inhibitors (ARSIs), in combination with the androgen deprivation therapy (ADT), which was the previous standard of care. Despite showing a similar clinical efficacy, ARSIs, all of which are administered orally, are different in terms of pharmacokinetic and drug-drug interactions (DDIs).

AREAS COVERED

This review covers the main pharmacokinetic characteristics of ARSIs that have been approved for the first-line therapy of mHSPC patients, underlying the differences among these molecules and focusing on the known or possible interactions with other drugs. Full-text articles and abstracts were searched in PubMed.

EXPERT OPINION

Since prostate cancer occurs mainly in older age, comorbidities and the consequent polypharmacy increase the DDI risk in mHSPC patients who are candidates for ARSI. Waiting for new therapeutic options, in the absence of direct comparisons, pharmacokinetic knowledge is essential to guide clinicians in prescribing ARSI in this setting.

Long-Term Pharmacokinetic Follow-Up of Abiraterone Acetate in Patients with Metastatic Castration-Resistant Prostate Cancer

This ABIGENE pharmacokinetic (PK) study sought mainly to characterize the unchanged drug PK during long-term abiraterone acetate (AA) administration in advanced prostate cancer patients (81 patients). It was observed that individual AA concentrations remained constant over treatment time, with no noticeable changes during repeated long-term drug administration for up to 120 days. There was no correlation between AA concentrations and survival outcomes. However, a significant association between higher AA concentrations and better clinical benefit was observed (p = 0.041). The safety data did not correlate with the AA PK data. A significant positive correlation (r = 0.40, p < 0.001) was observed between mean AA concentration and patient age: the older the patient, the higher the AA concentration. Patient age was found to impact steady-state AA concentration: the older the patient, the higher the mean AA concentration. Altogether, these data may help to guide future research and clinical trials in order to maximize the benefits of AA metastatic castration-resistant prostate cancer patients.

Demonstrating Bioequivalence for Two Dose Strengths of Niraparib and Abiraterone Acetate Dual-Action Tablets Versus Single Agents: Utility of Clinical Study Data Supplemented with Modeling and Simulation

BACKGROUND AND OBJECTIVE

The combination of niraparib and abiraterone acetate (AA) plus prednisone is under investigation for the treatment of patients with metastatic castration-resistant prostate cancer (mCRPC) and metastatic castration-sensitive prostate cancer (mCSPC). Regular-strength (RS) and lower-strength (LS) dual-action tablets (DATs), comprising niraparib 100 mg/AA 500 mg and niraparib 50 mg/AA 500 mg, respectively, were developed to reduce pill burden and improve patient experience. A bioequivalence (BE)/bioavailability (BA) study was conducted under modified fasting conditions in patients with mCRPC to support approval of the DATs.

METHODS

This open-label randomized BA/BE study (NCT04577833) was conducted at 14 sites in the USA and Europe. The study had a sequential design, including a 21-day screening phase, a pharmacokinetic (PK) assessment phase comprising three periods [namely (1) single-dose with up to 1-week run-in, (2) daily dose on days 1-11, and (3) daily dose on days 12-22], an extension where both niraparib and AA as single-agent combination (SAC; reference) or AA alone was continued from day 23 until discontinuation, and a 30-day follow-up phase. Patients were randomly assigned in a parallel-group design (four-sequence randomization) to receive a single oral dose of niraparib 100 mg/AA 1000 mg as a LS-DAT or SAC in period 1, and patients continued as randomized into a two-way crossover design during periods 2 and 3 where they received niraparib 200 mg/AA 1000 mg once daily as a RS-DAT or SAC. The design was powered on the basis of crossover assessment of RS-DAT versus SAC. During repeated dosing (periods 2 and 3, and extension phase), all patients also received prednisone/prednisolone 5 mg twice daily. Plasma samples were collected for measurement of niraparib and abiraterone plasma concentrations. Statistical assessment of the RS-DAT and LS-DAT versus SAC was performed on log-transformed pharmacokinetic parameters data from periods 2 and 3 (crossover) and from period 1 (parallel), respectively. Additional paired analyses and model-based bioequivalence assessments were conducted to evaluate the similarity between the LS-DAT and SAC.

RESULTS

For the RS-DAT versus SAC, the 90% confidence intervals (CI) of geometric mean ratios (GMR) for maximum concentration at a steady state (Cmax,ss) and area under the plasma concentration-time curve from 0-24 h at a steady state (AUC 0-24h,ss) were respectively 99.18-106.12% and 97.91-104.31% for niraparib and 87.59-106.69 and 86.91-100.23% for abiraterone. For the LS-DAT vs SAC, the 90% CI of GMR for AUC0-72h of niraparib was 80.31-101.12% in primary analysis, the 90% CI of GMR for Cmax,ss and AUC 0-24h,ss of abiraterone was 85.41-118.34% and 86.51-121.64% respectively, and 96.4% of simulated LS-DAT versus SAC BE trials met the BE criteria for both niraparib and abiraterone.

CONCLUSIONS

The RS-DAT met BE criteria (range 80%-125%) versus SAC based on 90% CI of GMR for Cmax,ss and AUC 0-24h,ss. The LS-DAT was considered BE to SAC on the basis of the niraparib component meeting the BE criteria in the primary analysis for AUC 0-72h; abiraterone meeting the BE criteria in additional paired analyses based on Cmax,ss and AUC 0-24h,ss; and the percentage of simulated LS-DAT versus SAC BE trials meeting the BE criteria for both.

CLINICALTRIALS

GOV IDENTIFIER

NCT04577833.

Aging of the adrenal gland and its impact on the stress response

This article discusses the physiological and anatomical changes of adrenal gland with age and the effects this has overall on how the organ responds to stress. Physiological changes entail a decrease in adrenocorticoid hormone secretion however cortisol levels remain intact leading to a disruptive stress response. Additionally, loss of zonation of the organ also occurs. Both characteristics in combination with chronic stress affect overall health. Complex interplay between adrenal aging and stress responsiveness is confounded further by the impact they expel on other systems, such as the thyroid hormone. The body undergoes age-related transformations modifying rate of cellular growth, differentiation, senescence, and hormone production. Given the multiplicity and complexity of hormones, their production must be considered to develop appropriate interventions to mitigate its effect on age related diseases in health.

Metastatic Castration-Resistant Prostate Cancer: Insights on Current Therapy and Promising Experimental Drugs

The therapeutic landscape of metastatic hormone sensitive and metastatic castration-resistant prostate cancer (mCRPC) is rapidly changing. We reviewed the current treatment options for mCRPC, with insights on new available therapeutic strategies. Chemotherapy with docetaxel or cabazitaxel (for patients progressing on docetaxel), as well as treatment with androgen receptor axis targeted therapies, and Radium-223 are well-established treatment options for patients with mCRPC. The advent of theragnostic in prostate cancer established Lutetium-177 (177Lu)-PSMA-617 as a new standard of care for PSMA-positive mCRPC previously treated with ARAT and taxane-based chemotherapy. Olaparib, a poly-ADP-ribose polymerase (PARP) inhibitor, is approved for selected patients with mCRPC progressed on ARATs and in combination with abiraterone acetate as first-line treatment for mCRPC. Immunotherapy showed limited efficacy in unselected patients with mCRPC and novel immunotherapy strategies need to be explored. The search for biomarkers is a growing field of interest in mCRPC, and predictive biomarkers are needed to support the choice of treatment and the development of tailored strategies.

Plasma extracellular vesicle circRNA signature and resistance to abiraterone in metastatic castration-resistant prostate cancer

BACKGROUND

We aimed to develop and validate a plasma extracellular vesicle circular RNA (circRNA)-based signature that can predict overall survival (OS) in first-line abiraterone therapy for metastatic castration-resistant prostate cancer (mCRPC) patients.

METHODS

In total, 582 mCRPC patients undergoing first-line abiraterone therapy from four institutions were sorted by three phases. In the discovery phase, 30 plasma samples from 30 case-matched patients with or without early progression were obtained to generate circRNA expression profiles using RNA sequencing. In the training phase, differentially expressed circRNAs were examined using digital droplet PCR in a training cohort (n = 203). The circRNA signature was constructed using a least absolute shrinkage and selection operator Cox regression to predict OS. In the validation phase, the prognostic ability of this signature was prospectively validated in two external cohorts (Cohort I, n = 183; Cohort II, n = 166).

RESULTS

We developed a five-circRNA signature, based on circCEP112, circFAM13A, circBRWD1, circVPS13C and circMACROD2, which successfully stratified patients into high-risk and low-risk groups. The prognostic ability of this signature was prospectively validated in two external cohorts (P < 0.0001, P < 0.0001). Patients with high-risk scores had shorter OS than patients with low-risk scores.

CONCLUSION

This five-circRNA signature is a reliable predictor of OS for mCRPC patients undergoing abiraterone.

AR and PI3K/AKT in Prostate Cancer: A Tale of Two Interconnected Pathways

Prostate cancer (PCa) is the most common cancer in men. The androgen receptor (AR) has a pivotal role in the pathogenesis and progression of PCa. Many therapies targeting AR signaling have been developed over the years. AR signaling inhibitors (ARSIs), including androgen synthesis inhibitors and AR antagonists, have proven to be effective in castration-sensitive PCa (CSPC) and improve survival, but men with castration-resistant PCa (CRPC) continue to have a poor prognosis. Despite a good initial response, drug resistance develops in almost all patients with metastatic CRPC, and ARSIs are no longer effective. Several mechanisms confer resistance to ARSI and include AR mutations but also hyperactivation of other pathways, such as PI3K/AKT/mTOR. This pathway controls key cellular processes, including proliferation and tumor progression, and it is the most frequently deregulated pathway in human cancers. A significant interaction between AR and the PI3K/AKT/mTOR signaling pathway has been shown in PCa. This review centers on the current scene of different AR and PI3K signaling pathway inhibitors, either as monotherapy or in combination treatments in PCa, and the treatment outcomes involved in both preclinical and clinical trials. A PubMed-based literature search was conducted up to November 2022. The most relevant and recent articles were selected to provide essential information and current evidence on the crosstalk between AR and the PI3K signaling pathways. The ClinicalTrials.gov registry was used to report information about clinical studies and their results using the Advanced research tool, filtering for disease and target.

Design, synthesis and anticancer activity of novel steroidal derivatives with D-ring fused or substituted N-heterocyclic systems

A series of novel D-ring fused or substituted steroidal N-heterocycles were synthesized, and their chemical structures were characterized by spectroscopic analysis. The anticancer activity of these compounds against four human cancer cell lines (MCF-7, H1299, HeLa and HepG2) were evaluated and the structure-activity relationship (SAR) was also investigated. Compound 3c displayed significant inhibitory activity on the four cancer cells with IC 50 values ranging from 3.88 to 10.05 µ M. Overall, these studies indicated that construction of N-heterocyclic system with D-ring substituted containing a double bond at C-16 and C-17 or D-ring fused with [17,16-d]azolo[1,5-a]pyrimidine could be a promising strategy to improve antitumor activity for steroids deserved further investigation.

Factors influencing survival in metastatic castration resistant prostate cancer therapy

INTRODUCTION

The number of patients with metastatic castration resistant prostate cancer (mCRPC) is expecting to increase due to the long-life expectancy of those with advanced disease who are also more commonly diagnosed today because of stage migration. Several compounds are available for treating these patients.

AREAS COVERED

We reviewed currently available treatments for mCRPC, their mechanism of action and resistance and we explored possible predictors of treatment success useful to predict survival in mCRPC patients.

EXPERT OPINION

A combination of molecular, clinical, pathological, and imaging features is necessary to correctly estimate patients' risk of death. The combination of these biomarkers may allow clinicians to tailor treatments based on cancer history and patients' features. The search of predictive biomarkers remains an unmet medical need for most patients with mCRPC.

Development of Abiraterone Acetate Nanocrystal Tablets to Enhance Oral Bioavailability: Formulation Optimization, Characterization, In Vitro Dissolution and Pharmacokinetic Evaluation

Abiraterone acetate is a prodrug of abiraterone used in combination with prednisone as a standard therapeutic strategy for hormone-resistant prostate cancer (mCRPC). Due to the poor solubility and permeability, the release and absorption of abiraterone acetate are low and reduce its bioavailability. In this project, abiraterone acetate tablets prepared using nanocrystal technology were developed to overcome the drawbacks of normal tablets by enhancing in vitro dissolution rate and oral bioavailability. The abiraterone acetate nanocrystal suspensions were prepared by top-down wet milling method using a planetary ball mill with the mixture of Poloxamer 407 and Poloxamer 188 as the optimized stabilizer at a ratio of 7:1. The optimized nanocrystals were freeze-dried and characterized using DLS, TEM, DSC, and XRD. The abiraterone acetate nanocrystal tablets significantly improve the in vitro dissolution rate of abiraterone acetate compared to raw materials. Although exhibiting a similar dissolution rate compared to the Zytiga^® tablets, the nanocrystal tablets significantly improve the oral bioavailability with C_max and AUC_0–t being 3.51-fold and 2.80-fold higher, respectively, in the pharmacokinetic study. The present data indicate that nanocrystal is a promising strategy for improving the dissolution and bioavailability of abiraterone acetate.

Risk of metabolic and cardiovascular adverse events with abiraterone or enzalutamide among men with advanced prostate cancer

BACKGROUND

Abiraterone and enzalutamide are the most common oral agents for the treatment of men with advanced prostate cancer. To understand their safety profiles in real-world settings, we examined the association between the use of abiraterone or enzalutamide and the risk of metabolic or cardiovascular adverse events while on treatment.

METHODS

Men with advanced prostate cancer and their use of abiraterone or enzalutamide were identified in a 20% sample of the 2010-2017 national Medicare claims. The primary composite outcome was the occurrence of a major metabolic or cardiovascular adverse event, defined as an emergency room visit or hospitalization associated with a primary diagnosis of diabetes, hypertension, or cardiovascular disease. The secondary composite outcome was the occurrence of a minor metabolic or cardiovascular adverse event, defined as an outpatient visit associated with a primary diagnosis of the aforementioned conditions. Risks were assessed separately for abiraterone and enzalutamide using Cox regression. All statistical tests were 2-sided.

RESULTS

Compared to men not receiving abiraterone, men receiving abiraterone were at increased risk of both a major composite adverse event (HR 1.77, 95% CI 1.53-2.05, P<0.001) and a minor composite adverse event (HR 1.24, 95% CI 1.05-1.47, P=0.01). Compared to men not receiving enzalutamide, men receiving enzalutamide were at an increased risk of a major composite adverse event (HR 1.22, 95% CI 1.01-1.48, P=0.04) but not a minor composite adverse event (HR 1.04, 95% CI 0.83-1.30, P=0.75).

CONCLUSION

Careful monitoring and management of men on abiraterone or enzalutamide through team-based approaches are critical.

Evolution of Androgen Deprivation Therapy (ADT) and Its New Emerging Modalities in Prostate Cancer: An Update for Practicing Urologists, Clinicians and Medical Providers

Androgen deprivation therapy (ADT) has been the main management strategy for prostate cancer for more than eight decades, nowadays achieved commonly by administration of luteinizing hormone-releasing hormone agonists. ADT markedly suppresses androgen hormones with the long-term risks of adverse events such as muscle weakness, impairment of glucose and lipid metabolism, impotence, osteoporosis, and secondary fractures. Extensive research has provided significantly better insight into the dynamics of ADT including identification of the benefits of sequential and combination therapies. This has led to the development of new pharmaceutical ADT modalities. This review provides a general overview of the evolution of ADT in the context of the new emerging pharmaceutical ADT modalities so that clinicians and medical providers have a better understanding of personalizing the available ADT options with their different risk-benefit profiles.

Abiraterone acetate versus nonsteroidal antiandrogen with androgen deprivation therapy for high-risk metastatic hormone-sensitive prostate cancer

BACKGROUND

Although prostate cancer is a very common form of malignancy in men, the clinical significance of androgen deprivation therapy (ADT) with abiraterone acetate versus the nonsteroidal antiandrogen bicalutamide has not yet been verified in patients with high-risk metastatic hormone-sensitive prostate cancer (mHSPC). The present study was designed to initiate this verification in real-world Japanese clinical practice.

METHODS

We retrospectively analyzed the records of 312 patients with high-risk mHSPC based on LATITUDE criteria and had received ADT with bicalutamide (n = 212) or abiraterone acetate (n = 100) between September 2015 and December 2020. Bicalutamide was given at 80 mg daily and abiraterone was given at 1000 mg daily as four 250-mg tablets plus prednisolone (5-10 mg daily). Overall survival (OS), cancer-specific survival (CSS), and time to castration-resistant prostate cancer (CRPC) were compared. The prognostic factor for time to CRPC was analyzed by Cox proportional hazard model.

RESULTS

Patients in the bicalutamide group were older, and more of them had poor performance status (≧2), than in the abiraterone group. Impaired liver function was noted in 2% of the bicalutamide group and 16% of the abiraterone group (p < 0.001). Median follow-up was 22.5 months for bicalutamide and 17 months for abiraterone (p < 0.001). Two-year OS and CSS for bicalutamide versus abiraterone was 77.8% versus 79.5% (p = 0.793) and 81.1% versus 82.5% (p = 0.698), respectively. Median time to CRPC was significantly longer in the abiraterone group than in the bicalutamide group (NA vs. 13 months, p < 0.001). In multivariate analysis, Gleason score ≧9, high alkaline phosphatase, high lactate dehydrogenase, liver metastasis, and bicalutamide were independent prognostic risk factors for time to CRPC. Abiraterone prolonged the time to CRPC in patients with each of these prognostic factors.

CONCLUSIONS

Despite limitations regarding the time-dependent bias, ADT with abiraterone acetate significantly prolonged the time to CRPC compared to bicalutamide in patients with high-risk mHSPC. However, further study with longer follow-up is needed.

LHRH sparing therapy in patients with chemotherapy-naïve, mCRPC treated with abiraterone acetate plus prednisone: results of the randomized phase II SPARE trial

BACKGROUND

Although the benefit of androgen deprivation therapy (ADT) continuation in metastatic castration-resistant prostate cancer (mCRPC) remains controversial, clinical evidence is lacking. Recent results indicated that treatment with abiraterone acetate (AA) plus prednisone (P) further suppresses serum testosterone levels over ADT alone, suggesting that continuation of ADT in the treatment of mCRPC may not be necessary.

METHODS

In this exploratory phase 2 study, mCRPC patients were randomized with a 1:1 ratio to receive either continued ADT plus AA + P (Arm A) or AA + P alone (Arm B). The primary endpoint was the rate of radiographic progression-free survival (rPFS) at month 12. Secondary endpoints included PSA-response rate, objective response, time to PSA progression and safety.

RESULTS

A total of 68 patients were equally randomized between the two study arms. Median testosterone-levels remained below castrate-levels throughout treatment in all patients. According to the intention-to-treat analysis the rPFS rate was 0.84 in Arm A and 0.89 in Arm B. Moderate and severe treatment-emergent adverse events were reported for 72% of the patients in Arm A and for 85% of the patients in Arm B.

CONCLUSIONS

AA + P treatment without ADT may be effective in mCRPC patients and ADT may not be necessary in patients receiving AA + P.

Useful predictors of progression-free survival for Japanese patients with LATITUDE-high-risk metastatic castration-sensitive prostate cancer who received upfront abiraterone acetate

Objective

Recently, hormonal therapy using abiraterone acetate, a second‐generation androgen receptor axis‐targeted agent, was reported to improve overall survival and progression‐free survival in men with LATITUDE‐high‐risk metastatic castration‐sensitive prostate cancer. This observational multicenter study aimed to assess the efficacy of upfront abiraterone acetate in Japanese patients with LATITUDE‐high‐risk metastatic castration‐sensitive prostate cancer.

Methods

The present study included 112 Japanese patients with LATITUDE‐high‐risk metastatic castration‐sensitive prostate cancer who received upfront abiraterone acetate at four institutions belonging to the Tokai Urologic Oncology Research Seminar group, between January 2018 and September 2020. Progression‐free survival and overall survival were assessed, and Cox regression analyses were carried out to evaluate the prognostic significance of upfront abiraterone acetate for progression‐free survival.

Results

Within a median follow‐up period of 13 months, the progression‐free survival and overall survival rates were 76.8% and 89.3%, respectively. Both univariate and multivariable Cox regression analyses showed that the presence of Gleason pattern 5, performance status and hemoglobin were independent predictors of progression‐free survival. The patients were subsequently divided into three groups as follows: group 1, 17 patients negative for these three independent progression‐free survival predictors; group 2, 49 patients with one positive independent progression‐free survival predictor; and group 3, 45 patients with two or three independent progression‐free survival predictors. Progression‐free survival was significantly different among these three groups (P < 0.001).

Conclusion

Upfront abiraterone acetate might provide satisfactory outcomes for Japanese patients with LATITUDE‐high‐risk metastatic castration‐sensitive prostate cancer. Gleason pattern 5, performance status and hemoglobin are potential predictors of progression‐free survival in Japanese patients with LATITUDE‐high‐risk metastatic castration‐sensitive prostate cancer who received upfront abiraterone acetate.

Neoadjuvant hormonal therapy before radical prostatectomy in high-risk prostate cancer

Patients with high-risk prostate cancer treated with curative intent are at an increased risk of biochemical recurrence, metastatic progression and cancer-related death compared with patients treated for low-risk or intermediate-risk disease. Thus, these patients often need multimodal therapy to achieve complete disease control. Over the past two decades, multiple studies on the use of neoadjuvant treatment have been performed using conventional androgen deprivation therapy, which comprises luteinizing hormone-releasing hormone agonists or antagonists and/or first-line anti-androgens. However, despite results from these studies demonstrating a reduction in positive surgical margins and tumour volume, no benefit has been observed in hard oncological end points, such as cancer-related death. The introduction of potent androgen receptor signalling inhibitors (ARSIs), such as abiraterone, apalutamide, enzalutamide and darolutamide, has led to a renewed interest in using neoadjuvant hormonal treatment in high-risk prostate cancer. The addition of ARSIs to androgen deprivation therapy has demonstrated substantial survival benefits in the metastatic castration-resistant, non-metastatic castration-resistant and metastatic hormone-sensitive settings. Intuitively, a similar survival effect can be expected when applying ARSIs as a neoadjuvant strategy in high-risk prostate cancer. Most studies on neoadjuvant ARSIs use a pathological end point as a surrogate for long-term oncological outcome. However, no consensus yet exists regarding the ideal definition of pathological response following neoadjuvant hormonal therapy and pathologists might encounter difficulties in determining pathological response in hormonally treated prostate specimens. The neoadjuvant setting also provides opportunities to gain insight into resistance mechanisms against neoadjuvant hormonal therapy and, consequently, to guide personalized therapy.

Development, Characterization, and Optimization of a Novel Abiraterone Acetate Formulation to Improve Biopharmaceutical Attributes Aided by Pharmacokinetic Modelling

Abiraterone acetate has very low bioavailability and drastic food effect to warrant a dosing regimen under fasting state only. Therefore, we aimed to develop and optimize a liquisolid compact formulation of abiraterone acetate to improve biopharmaceutical attributes aided by pharmacokinetic modelling and achieve dose reduction with no food effect on the formulation. Preliminary studies highlighted the importance of the selection of olive oil as a compatible vehicle. The pharmacokinetic model, integrated with gastrointestinal physiology, was used to predict fasted and fed state pharmacokinetic parameters. Optimization of the liquisolid formulation containing abiraterone acetate was carried at more than five times lower dose, i.e. 190 mg, compared to 1000 mg. A central composite design (CCD) was used to identify optimal levels of formulation factors, namely the amount of vehicle (olive oil), the amount of coating agent (silicon dioxide), and the amount of surfactant (polysorbate 80). Graphical optimization using the selected models in conjunction with maximization of the desirability was used to identify the optimized liquisolid formulation. The predicted pharmacokinetic parameters (fasted C_max 901.83 ng/mL, fasted AUC_inf 2723.82 ng·h/mL, fed C_max 1024.34 ng/mL, and fed AUC_inf 3041.83 ng·h/mL) of the optimized formulation were acceptable. Overall, the liquisolid compact formulation of abiraterone acetate was successfully developed and optimized. In vitro solubility and dissolution results aided by pharmacokinetic modelling also showed improved predicted bioavailability with greater than five times reduction in dose and elimination of food effect.

Prostate cancer treatment and the relationship of androgen deprivation therapy to cognitive function

Prostate cancer is the second most common form of cancer in men. For advanced, high risk prostate cancer, androgen deprivation therapy (ADT) is the preferred treatment and can induce remission, but resistance to ADT brings biochemical recurrence and progression of cancer. ADT brings adverse effects such as erectile dysfunction, decreased libido, and diminished physical strength. It is estimated that between 25 and 50% of men on ADT manifest some form of cognitive dysfunction that may be self-reported or reported by a family member. There is concern that impaired cognitive function with ADT is due to loss of testosterone support. Testosterone and its metabolites are known to possess neuroprotective properties. While a direct causal relationship between ADT and cognitive decline in prostate cancer patients has not been established, this review describes the controversy surrounding the possible connection between ADT and neurocognitive deterioration. The cellular and molecular mechanisms believed to underlie the protection of neuronal integrity by androgens are discussed. Results from animal models and human clinical studies are presented. Finally, we call attention to lifestyle modifications that may minimize cognitive issues in prostate cancer patients.

Heterocyclic androstane and estrane d-ring modified steroids: Microwave-assisted synthesis, steroid-converting enzyme inhibition, apoptosis induction, and effects on genes encoding estrogen inactivating enzymes

d-ring-fused and d-homo lactone compounds in estratriene and androstane series were synthesized using microwave-assisted reaction conditions. Microwave-irradiated synthesis methods were convenient and effective, and provided high yields with short reaction times. Their inhibition of C_17,20-lyase and 17β-hydroxysteroid dehydrogenase type 1 (17β-HSD1) activities were studied in in vitro enzyme assays. d-ring-fused triazolyl estrone analog 24 showed potent inhibition of NADH-complexed 17β-HSD1, with a binding affinity similar to that of the substrate estrone; its inhibition against NADPH-complexed 17β-HSD1 was markedly weaker. Compound 24 also significantly and selectively reduced proliferation of cancer cell lines of gynecological origin. This estrane triazole changed the cell cycle and induced apoptosis of HeLa, SiHa, and MDA-MB-231 cancer cells, measured by both increased subG1 fraction of cells and activation of caspase-independent signaling pathways. A third mode of anti-estrogenic action of 24 saw increased mRNA expression of the SULT1E1 gene in HeLa cells; in contrast, its 3-benzyloxy analog 23 increased mRNA expression of the HSD17B2 gene, thus showing pronounced pro-drug anti-estrogenic activity. Estradiol-derived d-ring triazole compound 24 thus acts at the enzyme, gene expression and cellular levels to decrease the production of active estrogen hormones, demonstrating its pharmacological potential.

A phase 2 randomized clinical trial of abiraterone plus ADT, apalutamide, or abiraterone and apalutamide in patients with advanced prostate cancer with non-castrate testosterone levels (LACOG 0415)

BACKGROUND

Androgen deprivation therapy (ADT) combined with apalutamide, abiraterone acetate plus prednisone, enzalutamide, or docetaxel are the standard treatments for advanced castration-sensitive prostate cancer (CSPC). We investigated ADT-free alternatives for advanced CSPC.

PATIENTS AND METHODS

LACOG 0415 is a phase 2, open-label, non-comparative, randomized trial. Patients with advanced CSPC were randomized (1:1:1) to receive goserelin plus abiraterone acetate and prednisone (ADT plus AAP arm), apalutamide (APA arm), or apalutamide plus abiraterone acetate and prednisone (APA plus AAP arm). The primary endpoint was the proportion of patients with PSA of ≤0.2 ng/mL at week 25 in the modified intention-to-treat population. Safety analyses were performed in all patients with at least one dose of the study drug.

RESULTS

Of 128 randomized patients, 120 patients were evaluable for PSA response at week 25; 17.2% had a high-risk biochemical recurrence, 8.6% had locally advanced disease, and 74.2% had distant metastases. At week 25, PSA of ≤0.2 ng/mL was observed in 75.6% (95%CI 59.7%-87.6%), 60.0% (95%CI 43.3%-75.1%), and 79.5% (95%CI 63.5%-90.7%) of patients in ADT plus AAP, APA, and APA plus AAP arms, respectively. PSA decline of ≥80% was observed in 100%, 90.0%, and 97.4%, respectively. Grade 3-4 AEs were observed in 31.0%, 21.4% and 36.4%, respectively. Testosterone levels increased significantly in the APA arm and decreased significantly in ADT plus AAP and APA plus AAP arms.

CONCLUSIONS

ADT-free alternatives provide a high PSA response in advanced CSPC, although the APA arm did not reach the expected rate of PSA of ≤0.2 ng/mL at week 25. These results warrant further investigation of ADT-free treatments as alternatives in advanced CSPC.

SOURCE STUDY REGISTRATION

ClinicalTrials.govNCT02867020.

Hijacking Sexual Immuno-Privilege in GBM-An Immuno-Evasion Strategy

Regulatory T-cells (Tregs) are immunosuppressive T-cells, which arrest immune responses to 'Self' tissues. Some immunosuppressive Tregs that recognize seminal epitopes suppress immune responses to the proteins in semen, in both men and women. We postulated that GBMs express reproductive-associated proteins to manipulate reproductive Tregs and to gain immune privilege. We analyzed four GBM transcriptome databases representing ≈900 tumors for hypoxia-responsive Tregs, steroidogenic pathways, and sperm/testicular and placenta-specific genes, stratifying tumors by expression. In silico analysis suggested that the presence of reproductive-associated Tregs in GBM tumors was associated with worse patient outcomes. These tumors have an androgenic signature, express male-specific antigens, and attract reproductive-associated Related Orphan Receptor C (RORC)-Treg immunosuppressive cells. GBM patient sera were interrogated for the presence of anti-sperm/testicular antibodies, along with age-matched controls, utilizing monkey testicle sections. GBM patient serum contained anti-sperm/testicular antibodies at levels > six-fold that of controls. Myeloid-derived suppressor cells (MDSCs) and tumor-associated macrophages (TAMs) are associated with estrogenic tumors which appear to mimic placental tissue. We demonstrate that RORC-Tregs drive poor patient outcome, and Treg infiltration correlates strongly with androgen levels. Androgens support GBM expression of sperm/testicular proteins allowing Tregs from the patient's reproductive system to infiltrate the tumor. In contrast, estrogen appears responsible for MDSC/TAM immunosuppression.

Treatment Pattern and Outcomes with Systemic Therapy in Men with Metastatic Prostate Cancer in the Real-World Patients in the United States

Simple Summary

Novel hormonal therapies (such as abiraterone and enzalutamide) and docetaxel are approved treatments for metastatic prostate cancer. Upfront use of these agents has been shown to improve overall survival. However, we do not know the real-world treatment patterns of these agents or the comparative effectiveness of these agents after treatment with a prior novel hormonal therapy in patients with metastatic prostate cancer. In this large study, we found that most patients with metastatic prostate cancer received only androgen deprivation therapy as upfront therapy without novel hormonal therapies or docetaxel. In patients treated with one novel hormonal therapy, alternate novel hormonal therapy was the most common next therapy and was associated with improved overall survival over docetaxel with the caveat of this being a non-randomized comparison. The study’s limitations also include its retrospective design.

Abstract

Background: Both novel hormonal therapies and docetaxel are approved for treatment of metastatic prostate cancer (mPC; in castration sensitive or refractory settings). Present knowledge gaps include lack of real-world data on treatment patterns in patients with newly diagnosed mPC, and comparative effectiveness of novel hormonal therapies (NHT) versus docetaxel after treatment with a prior NHT. Methods: Herein we extracted patient-level data from a large real-world database of patients with mPC in United States. Utilization of NHT or docetaxel for mPC and comparative effectiveness of an alternate NHT versus docetaxel after one prior NHT was evaluated. Comparative effectiveness was examined via Cox proportional hazards model with propensity score matching weights. Each patient’s propensity for treatment was modeled via random forest based on 22 factors potentially driving treatment selection. Results: The majority of patients (54%) received only androgen deprivation therapy for mPC. In patients treated with an NHT, alternate NHT was the most common next therapy and was associated with improved median overall survival over docetaxel (abiraterone followed by docetaxel vs. enzalutamide (8.7 vs. 15.6 months; adjusted hazards ratio; aHR 1.32; p = 0.009; and enzalutamide followed by docetaxel vs. abiraterone (9.7 vs. 13.2 months aHR 1.40; p = 0.009). Limitations of the study include retrospective design.

Hormonal manipulation in androgen signaling: a narrative review on using novel androgen therapy agents to optimize clinical outcomes and minimize side effects for prostate cancer patients

Prostate cancer is a significant public health burden and one of the most common cancers globally and in the United States. The current cornerstone of prostate cancer systemic treatment involves the suppression of androgen receptor (AR) signaling, either by reducing the body's testosterone production or inhibiting its binding to AR and its subsequent gene regulatory network driving carcinogenesis. This signaling pathway plays a central role in both hormone sensitive and castration resistant prostate cancer (CRPC), as evidenced by survival benefit when AR-targeted therapies are applied in the setting of CRPC. With the development of increasingly potent central and peripherally acting androgen targeting agents physicians treating prostate cancer can expect to treat their patients for a longer duration with a larger selection of effective agents. In this setting clinicians are now faced with questions of how to best tailor treatments for the prostate cancer patient to not only maximize overall survival but also optimize the quality of life and mitigate toxicity. In this manuscript we discuss the newer hormone therapy agents for prostate cancer and highlight what they indicate about optimizing medical castration, and the potential value of peripheral blockade.

Steroid switch after progression on abiraterone plus prednisone in patients with metastatic castration-resistant prostate cancer: A systematic review

BACKGROUND

Emerging evidence indicates that patients with metastatic castration-resistant prostate cancer could respond to steroid switch from prednisone (P) to dexamethasone (D) following progression on abiraterone acetate plus prednisone (AA+P).

OBJECTIVES

Conducting a systematic review to evaluate the efficacy, safety, and prognostic factors of steroid switch.

MATERIALS AND METHODS

We systematically searched Pubmed, Web of Science, and American Society of Clinical Oncology annual meeting abstracts published up to October 2020. Literature review, study selection, and data extraction were conducted by two reviewers. Risk of bias (RoB) and quality of evidence were assessed. A systematic review and pooled analysis were performed.

RESULTS

Nine studies were eligible for inclusion. All of the included patients were progression on AA+P. Pooled rates of PSA50 and PSA30 on abiraterone acetate plus dexamethasone (AA+D) were 0.24 (95%CI [0.18,0.30]) and 0.42 (95%CI [0.36,0.48]), respectively. Subgroup analysis indicated more favorable PSA50 and PSA30 rates on AA+D when switching from P to D only based on PSA progression. Median time to PSA progression on AA+D ranged from 2.73 to 11.38 months. Definitions of progression free survival were variable. Reported median progression free survival on AA+D ranged from 2.52 to 11.8 months. Median overall survival on AA+D varied from 4.11 to 20.9 months. All patients tolerated well on AA+D, and no grade 3 to 4 adverse events were reported. Baseline characteristics of patients, previous treatment and its response, and genetic alterations might all play roles in the response in the response toward the AA+D regimen.

CONCLUSIONS

The present systematic review suggested that steroid switch from P to D might be an effective and safe treatment strategy in a subset of patients with metastatic castration-resistant prostate cancer after PSA progression on AA+P.

Rational Design of Novel Inhibitors of α-Glucosidase: An Application of Quantitative Structure Activity Relationship and Structure-Based Virtual Screening

α-Glucosidase is considered a prime drug target for Diabetes Mellitus and its inhibitors are used to delay carbohydrate digestion for the treatment of diabetes mellitus. With the aim to design α-glucosidase inhibitors with novel chemical scaffolds, three folds ligand and structure based virtual screening was applied. Initially linear quantitative structure activity relationship (QSAR) model was developed by a molecular operating environment (MOE) using a training set of thirty-two known inhibitors, which showed good correlation coefficient (r² = 0.88), low root mean square error (RMSE = 0.23), and cross-validated correlation coefficient r² (q² = 0.71 and RMSE = 0.31). The model was validated by predicting the biological activities of the test set which depicted r² value of 0.82, indicating the robustness of the model. For virtual screening, compounds were retrieved from zinc is not commercial (ZINC) database and screened by molecular docking. The best docked compounds were chosen to assess their pharmacokinetic behavior. Later, the α-glucosidase inhibitory potential of the selected compounds was predicted by their mode of binding interactions. The predicted pharmacokinetic profile, docking scores and protein-ligand interactions revealed that eight compounds preferentially target the catalytic site of α-glucosidase thus exhibit potential α-glucosidase inhibition in silico. The α-glucosidase inhibitory activities of those Hits were predicted by QSAR model, which reflect good inhibitory activities of these compounds. These results serve as a guidelines for the rational drug design and development of potential novel anti-diabetic agents.

An up-to-date evaluation of abiraterone for the treatment of prostate cancer

Introduction: Abiraterone acetate, an oral 17-alpha-hydroxylase inhibitor, effectively prevents the synthesis of androgens from steroid precursors. Abiraterone has become a standard of care in patients with metastatic prostate cancer due to its efficacy in both castrate-sensitive and castrate-resistant disease when given in combination with androgen deprivation therapy (ADT). Abiraterone may have a role in additional aspects of prostate cancer treatment in the future.Areas covered: The present article focuses on the development and establishment of abiraterone among the available treatment options for prostate cancer. A literature search was performed in PubMed/Medline for prior studies and reviews of the drug. Current clinical trials were examined in the Clinicaltrials.gov database.Expert opinion: Abiraterone has shown efficacy in castrate-resistant metastatic prostate cancer, providing an additional degree of hormonal sensitivity for tumors resistant to ADT. Impressively, abiraterone in conjunction with ADT as a first-line treatment for castrate-sensitive prostate cancer also confers a significant overall survival benefit compared to ADT alone. With minimal additional toxicity, abiraterone has established itself as a well-tolerated, convenient, and effective treatment option. Ongoing studies are expected to broaden the drug's indications as well as its preference among other prostate cancer therapies.

Angiotensin System Inhibitors May Improve Outcomes of Patients With Castration-Resistant Prostate Cancer During Abiraterone Acetate Treatment-A Cardio-Oncology Study

Background

Abiraterone acetate (ABI) therapy improves overall survival in metastatic prostate cancer (PC) patients; however, this effect may be diminished by concurrent comorbidities. We aimed to evaluate the influence of pre-existing chronic diseases and concomitant medications on the course of ABI treatment among post-chemotherapy patients with metastatic castration-resistant prostate cancer patients (mCRPC).

Methods

From the Polish National Health Fund database, we identified 93 post-chemotherapy, mCRPC patients, who were qualified for ABI treatment in our oncology center between 2014 and 2018. Survival curves and Cox proportional hazard models (univariate and multivariate) were used to determine the predictors for longer time to treatment failure (TTF) of ABI therapy.

Results

Median TTF was 9,8 months (IQR: 0,6–56,5) Factors associated with longer TTF were: well controlled hypertension (HR, 0.59; 95% CI. 0.38–0.90; p = 0.02), stable coronary artery disease (HR, 0.56; 95% CI, 0.33–0.95; p=0.03), the use of angiotensin system inhibitor (ASi) (HR, 0.61; 95% CI 0.4–0.94; p = 0,02). Patients who were receiving ASi had median TTF of 12.2 months versus 5.8 months in men who did not receive ASi before ABI initiation. At the start of ABI therapy, the aforementioned groups did not differ in terms of well-known prognostic factors: Gleason score, PSA level, or the number of patients with visceral metastases. In a multivariate analysis, the use of ASi remained statistically significant, even after adjustment for well-known oncological factors (HR, 0.57; 95% CI, 0.34–0.98; p = 0.04).

Conclusions

The use of ASi may enhance and prolong ABI therapy in post-docetaxel mCRPC patients and may potentially be considered a new, non-oncological, predictive factor for longer TTF. This association requires a prospective validation.

Endocrine consequences of treatment with the new androgen receptor axis-targeted agents for advanced prostate cancer

PURPOSE

Prostate cancer (PCa) is the commonest non-cutaneous malignancy worldwide and the second cause of cancer death among males in the USA. Approval of the new androgen receptor axis-targeted (ARAT) agents (abiraterone acetate, enzalutamide, apalutamide, and darolutamide) has altered the course of advanced PCa. We aimed to assess the endocrine and metabolic adverse events associated with treatment using ARAT compounds.

METHODS

We searched the PubMed, Cochrane Library, and Scopus databases from database inception to August 2020. We included randomized controlled trials reporting the endocrine and metabolic side effects of ARAT agents compared to each other or to placebo.

RESULTS

Although metastatic PCa remains incurable, ARAT medications combined with androgen deprivation therapy improve overall metastasis-free and progression-free survival in metastatic hormone-sensitive PCa, non-metastatic castration-resistant PCa, and metastatic castration-resistant PCa patients. This benefit comes at the cost of certain endocrine and metabolic consequences. Treatment with abiraterone acetate induces mineralocorticoid excess, hypokalemia, hypertension, elevated liver function tests, insulin resistance, and hyperglycemia. Enzalutamide may induce or worsen hypertension and increase the risk of falls and fractures in elderly patients, while common endocrine adverse events of apalutamide include hypothyroidism, hypertension, and skin rash. On the other hand, darolutamide seems to have a somewhat safer endocrine and metabolic profile.

CONCLUSION

Treatment of advanced PCa should be personalized, with administration of a combination of androgen deprivation therapy, ARAT agents, and chemotherapy being based on the patient's safety profile and the risk of side effects.

The Right Dose: From Phase I to Clinical Practice

To realize the full potential of promising new anticancer drugs, it is of paramount importance to administer them at the right dose. The aim of this educational article is to provide several opportunities to optimize anticancer drug dosing, focusing on oral targeted therapies. First, therapeutic drug monitoring can optimize exposure in individual patients, if the optimal concentration is known. This approach is of particular interest in regard to oral kinase inhibitors with high interindividual pharmacokinetic variability. If exposure is related to response, then therapeutic drug monitoring is potentially feasible, although the clinical utility of this approach has not yet been established. Other approaches to reduce variability include administration of more frequent, smaller doses and administration under optimal prandial conditions. However, for many drugs, the labeled dose has not been demonstrated to be the optimal dose; for such agents, the vast majority of patients may be receiving excessive doses, which results in excessive toxicity. Furthermore, administration of lower off-label doses may reduce both medical and financial toxicity. These strategies should be applied from registration studies to clinical practice, with the goal of better optimizing anticancer treatment.

Bone metastasis: mechanisms, therapies, and biomarkers

Skeletal metastases are frequent complications of many cancers, causing bone complications (fractures, bone pain, disability) that negatively affect the patient's quality of life. Here, we first discuss the burden of skeletal complications in cancer bone metastasis. We then describe the pathophysiology of bone metastasis. Bone metastasis is a multistage process: long before the development of clinically detectable metastases, circulating tumor cells settle and enter a dormant state in normal vascular and endosteal niches present in the bone marrow, which provide immediate attachment and shelter, and only become active years later as they proliferate and alter the functions of bone-resorbing (osteoclasts) and bone-forming (osteoblasts) cells, promoting skeletal destruction. The molecular mechanisms involved in mediating each of these steps are described, and we also explain how tumor cells interact with a myriad of interconnected cell populations in the bone marrow, including a rich vascular network, immune cells, adipocytes, and nerves. We discuss metabolic programs that tumor cells could engage with to specifically grow in bone. We also describe the progress and future directions of existing bone-targeted agents and report emerging therapies that have arisen from recent advances in our understanding of the pathophysiology of bone metastases. Finally, we discuss the value of bone turnover biomarkers in detection and monitoring of progression and therapeutic effects in patients with bone metastasis.

Cardiovascular Complications of Prostate Cancer Treatment

Treatment of prostate cancer (PC) is a rapidly evolving field of pharmacology research. In recent years, numerous novel therapeutics that improve survival and ameliorate disease control have been approved. Currently, the systemic treatment for prostate neoplasm consists of hormonal therapy, chemotherapy, immunotherapy, radiopharmaceuticals, targeted therapy, and supportive agents (e.g., related to bone health). Unfortunately, many of them carry a risk of cardiovascular complications, which occasionally pose a higher mortality threat than cancer itself. This article provides a unique and comprehensive overview of the prevalence and possible mechanisms of cardiovascular toxicities of all PC therapies, including state-of-the-art antineoplastic agents. Additionally, this article summarizes available recommendations regarding screening and prevention of the most common cardiac complications among patients with advanced cancer disease.

Gonadotropin-Releasing Hormone Receptors in Prostate Cancer: Molecular Aspects and Biological Functions

Pituitary Gonadotropin-Releasing Hormone receptors (GnRH-R) mediate the activity of the hypothalamic decapeptide GnRH, thus playing a key role in the regulation of the reproductive axis. Early-stage prostate cancer (PCa) is dependent on serum androgen levels, and androgen-deprivation therapy (ADT), based on GnRH agonists and antagonists, represents the standard therapeutic approach for PCa patients. Unfortunately, the tumor often progresses towards the more aggressive castration-resistant prostate cancer (CRPC) stage. GnRH receptors are also expressed in CRPC tissues, where their binding to both GnRH agonists and antagonists is associated with significant antiproliferative/proapoptotic, antimetastatic and antiangiogenic effects, mediated by the Gαi/cAMP signaling cascade. GnRH agonists and antagonists are now considered as an effective therapeutic strategy for CRPC patients with many clinical trials demonstrating that the combined use of these drugs with standard therapies (i.e., docetaxel, enzalutamide, abiraterone) significantly improves disease-free survival. In this context, GnRH-based bioconjugates (cytotoxic drugs covalently linked to a GnRH-based decapeptide) have been recently developed. The rationale of this treatment is that the GnRH peptide selectively binds to its receptors, delivering the cytotoxic drug to CRPC cells while sparing nontumor cells. Some of these compounds have already entered clinical trials.

Prognostic Value of Androgen Receptor Splice Variant 7 in the Treatment of Metastatic Castration-Resistant Prostate Cancer: A Systematic Review and Meta-Analysis

Background

The prognostic value of androgen receptor splice variant 7 (AR-V7) for the treatment response of metastatic castration-resistant prostate cancer (mCRPC) remains unclear. In this study, we aimed to synthesize relevant studies that assessed the prognostic value of AR-V7 status for the treatment response of mCRPC patients treated with androgen receptor signalling inhibitors (ARSis) and chemotherapy.

Methods

We searched the PubMed, Embase, and MEDLINE databases by using the keywords AR-V7 and prostate cancer to identify relevant studies published before 25 September 2019. The main outcomes were prostate-specific antigen (PSA) response, progression-free survival (PFS), and overall survival (OS). Pooled odds ratios (ORs) and hazard ratios (HRs) with 95% confidence intervals (CIs) were calculated using a random effects model. The quality of the included studies was assessed using the Newcastle-Ottawa Quality Assessment Scale.

Results

A total of 1,545 patients from 21 studies were included. For the mCRPC patients treated with ARSis, AR-V7-positive patients had a lower PSA response rate (OR 6.01, 95% CI 2.88–12.51; P < 0.001), shorter PFS (HR 2.56, 95% CI 1.80–3.64; P < 0.001) and shorter OS (HR 4.28, 95% CI 2.92–6.27; P < 0.001) than AR-V7-negative patients. Although AR-V7-positive patients treated with chemotherapy also had a lower PSA response rate (OR 2.23, 95% CI 1.38–3.62; P = 0.001) and shorter OS than AR-V7-negative patients (HR 1.60, 95% CI 1.02–2.53; P = 0.043), there was no significant difference in PFS (HR 1.05, 95% CI 0.74–1.49; P = 0.796) between these groups. Furthermore, AR-V7-positive patients receiving ARSis had a shorter median OS than those receiving chemotherapy (HR 3.50, 95% CI 1.98–6.20; P < 0.001); There was no significant difference among AR-V7-negative patients (HR 1.30, 95% CI 0.64–2.62; P = 0.47).

Conclusions

AR-V7 is a potential biomarker of treatment resistance in mCRPC patients. AR-V7-positive mCRPC patients had poorer treatment outcomes than AR-V7-nagetive patients when treated with ARSis. AR-V7-positive patients have better outcomes when treated with taxane than ARSis. Furthermore, the ability of AR-V7 status to predict treatment outcomes varies from different detection methods. The detection of AR-V7 before treatment is important for the selection of treatment modalities for mCRPC patients.

Does the Addition of Abiraterone to Castration Affect the Reduction in Bone Mineral Density?

BACKGROUND/AIM

The in vivo effect of abiraterone on bone mineral density (BMD) in addition to androgen deprivation therapy was examined using a murine model.

MATERIALS AND METHODS

The mice were separated into the following groups: control, abiraterone, castration, and castration+abiraterone. The percentage change in the ratio of bone to tissue volume (BV/TV), number of osteoblasts and osteoclasts, and the serum level of bone markers were compared on day 21.

RESULTS

The BV/TV ratio of the abiraterone, castration, and castration+abiraterone groups was lower than that of the control group. However, the change in the BV/TV ratio in the castration+abiraterone group was not significantly different from that in the castration group. There was no significant difference in the serum TRAP5b level and the number of osteoclasts and osteoblasts between the castration+abiraterone and the castration groups.

CONCLUSION

The addition of abiraterone to castration did not affect BMD in the murine model.

Adding carboplatin to chemotherapy regimens for metastatic castrate-resistant prostate cancer in postsecond generation hormone therapy setting: Impact on treatment response and survival outcomes

BACKGROUND

The clinical course in metastatic castrate-resistant prostate cancer (mCRPC) can be complicated when patients have disease progression after prior treatment with second generation hormone therapy (second HT), such as enzalutamide or abiraterone. Currently, limited data exist regarding the optimal choice of chemotherapy for mCRPC after failing second generation hormone therapy. We sought to evaluate three common chemotherapy regimens in this setting.

METHODS

We retrospectively identified 150 mCRPC patients with disease progression on enzalutamide or abiraterone. Of these 150 patients, 92 patients were chemo-naïve while 58 patients had previously received docetaxel chemotherapy before being started on second HT. After failing second HT, 90 patients were assigned for docetaxel-alone (group A), 33 patients received carboplatin plus docetaxel (group B), while 27 patients received cabazitaxel-alone (Group C). A favorable response was defined by more than or equal to 50% reduction in prostate-specific antigen from the baseline level after a complete course of chemotherapy. Survival outcomes were assessed for 30-month overall survival.

RESULTS

Patients in group (B) were 2.6 times as likely to have a favorable response compared to patients in group (A) (OR = 2.625, 95%CI: 1.15-5.99) and almost three times compared to patients in group (C) (OR = 2.975, 95%CI: 1.04-8.54) (P = .0442). 30-month overall survival was 70.7%, 38.9% and 30.3% for group (B), (A), and (C), respectively (P = .008). We report a Hazard Ratio of 3.1 (95% CI, 1.31-7.35; P = .0037) between patients in group (A) versus those in group (B) and a Hazard Ratio of 4.18 (95% CI, 1.58-11.06; P = .0037) between patients in group (C) compared to those in group (B) CONCLUSION: This data demonstrates improved response and overall survival in treatment-refractory mCRPC with a chemotherapy regimen of docetaxel plus carboplatin when compared to docetaxel alone or cabazitaxel alone. Further investigations are required.

CYP17A1 polymorphism c.-362T>C predicts clinical outcome in metastatic castration-resistance prostate cancer patients treated with abiraterone

BACKGROUND

Abiraterone became a standard hormonal therapy for patients with metastatic castration-resistance prostate cancer (mCRPC). However, patients may experience primary resistance to treatment. To date, few predictive biomarkers of efficacy have been identified. Our aim was to investigate the association between the single nucleotide polymorphism (SNP) c.-362T>C in the CYP17A1 gene, and clinical outcome in mCRPC patients treated with abiraterone.

PATIENTS AND METHODS

mCRPC patients candidate to receive abiraterone were enrolled in the present retrospective pharmacogenetic study. Based on a literature selection, CYP17A1 rs2486758 (c.-362T > C) was selected and analysed by real-time PCR on genomic DNA extracted from whole blood. Univariate analysis was performed to test the association between the SNP and treatment-related clinical outcomes.

RESULTS

Sixty mCRPC patients were enrolled in the present study. Patients carrying the mutant CYP17A1 c.-362CT/CC genotypes showed a shorter median progression-free survival (PFS) and prostate-specific antigen-PFS (PSA-PFS) compared to patients carrying the TT genotype (10.7 vs 14.2 months and 8 vs 16 months, respectively; p = 0.04). No association between the selected SNP and the overall survival was found.

CONCLUSIONS

These findings suggest an association between CYP17A1 c.-362T>C polymorphism and poorer clinical outcome with abiraterone for mCRPC patients. However, further validations on larger cohort of patients are needed to confirm its role as a predictive biomarker for abiraterone resistance.

COVID-19 and androgen-targeted therapy for prostate cancer patients

The current pandemic (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a global health challenge with active development of antiviral drugs and vaccines seeking to reduce its significant disease burden. Early reports have confirmed that transmembrane serine protease 2 (TMPRSS2) and angiotensin converting enzyme 2 (ACE2) are critical targets of SARS-CoV-2 that facilitate viral entry into host cells. TMPRSS2 and ACE2 are expressed in multiple human tissues beyond the lung including the testes where predisposition to SARS-CoV-2 infection may exist. TMPRSS2 is an androgen-responsive gene and its fusion represents one of the most frequent alterations in prostate cancer. Androgen suppression by androgen deprivation therapy and androgen receptor signaling inhibitors form the foundation of prostate cancer treatment. In this review, we highlight the growing evidence in support of androgen regulation of TMPRSS2 and ACE2 and the potential clinical implications of using androgen suppression to downregulate TMPRSS2 to target SARS-CoV-2. We also discuss the future directions and controversies that need to be addressed in order to establish the viability of targeting TMPRSS2 and/or ACE2 through androgen signaling regulation for COVID-19 treatment, particularly its relevance in the context of prostate cancer management.

Slow-, Tight-Binding Inhibition of CYP17A1 by Abiraterone Redefines Its Kinetic Selectivity and Dosing Regimen

Substantial evidence underscores the clinical efficacy of inhibiting CYP17A1-mediated androgen biosynthesis by abiraterone for treatment of prostate oncology. Previous structural analysis and in vitro assays revealed inconsistencies surrounding the nature and potency of CYP17A1 inhibition by abiraterone. Here, we establish that abiraterone is a slow-, tight-binding inhibitor of CYP17A1, with initial weak binding preceding the subsequent slow isomerization to a high-affinity CYP17A1-abiraterone complex. The in vitro inhibition constant of the final high-affinity CYP17A1-abiraterone complex ( ( K _i * = 0.39 nM )yielded a binding free energy of -12.8 kcal/mol that was quantitatively consistent with the in silico prediction of -14.5 kcal/mol. Prolonged suppression of dehydroepiandrosterone (DHEA) concentrations observed in VCaP cells after abiraterone washout corroborated its protracted CYP17A1 engagement. Molecular dynamics simulations illuminated potential structural determinants underlying the rapid reversible binding characterizing the two-step induced-fit model. Given the extended residence time (42 hours) of abiraterone within the CYP17A1 active site, in silico simulations demonstrated sustained target engagement even when most abiraterone has been eliminated systemically. Subsequent pharmacokinetic-pharmacodynamic (PK-PD) modeling linking time-dependent CYP17A1 occupancy to in vitro steroidogenic dynamics predicted comparable suppression of downstream DHEA-sulfate at both 1000- and 500-mg doses of abiraterone acetate. This enabled mechanistic rationalization of a clinically reported PK-PD disconnect, in which equipotent reduction of downstream plasma DHEA-sulfate levels was achieved despite a lower systemic exposure of abiraterone. Our novel findings provide the impetus for re-evaluating the current dosing paradigm of abiraterone with the aim of preserving PD efficacy while mitigating its dose-dependent adverse effects and financial burden. SIGNIFICANCE STATEMENT: With the advent of novel molecularly targeted anticancer modalities, it is becoming increasingly evident that optimal dose selection must necessarily be predicated on mechanistic characterization of the relationships between target exposure, drug-target interactions, and pharmacodynamic endpoints. Nevertheless, efficacy has always been perceived as being exclusively synonymous with affinity-based measurements of drug-target binding. This work demonstrates how elucidating the slow-, tight-binding inhibition of CYP17A1 by abiraterone via in vitro and in silico analyses was pivotal in establishing the role of kinetic selectivity in mediating time-dependent CYP17A1 engagement and eventually downstream efficacy outcomes.

Overview of AKR1C3: Inhibitor Achievements and Disease Insights

Human aldo-keto reductase family 1 member C3 (AKR1C3) is known as a hormone activity regulator and prostaglandin F (PGF) synthase that regulates the occupancy of hormone receptors and cell proliferation. Because of the overexpression in metabolic diseases and various hormone-dependent and -independent carcinomas, as well as the emergence of clinical drug resistance, an increasing number of studies have investigated AKR1C3 inhibitors. Here, we briefly review the physiological and pathological function of AKR1C3 and then summarize the recent development of selective AKR1C3 inhibitors. We propose our viewpoints on the current problems associated with AKR1C3 inhibitors with the aim of providing a reference for future drug discovery and potential therapeutic perspectives on novel, potent, selective AKR1C3 inhibitors.

Pharmacotherapeutic strategies for castrate-resistant prostate cancer

INTRODUCTION

Metastatic castration-resistant prostate cancer (CRPC) is a potentially symptomatic disease with an eventual lethal outcome. Novel pharmaceutical agents are continuously studied with encouraging results in CRPC.

AREAS COVERED

In this perspective, the authors present established and promising pharmacotherapeutic strategies for the management of CRPC; both with and without metastases. Apart from the different treatment strategies, the authors present the relevant sequence of treatment through disease progression.

EXPERT OPINION

Usually, docetaxel should be considered the first line treatment in mCRPC. Abiraterone acetate (AA) plus prednisone or enzalutamide (ENZ) could be alternative treatments in chemotherapy naïve patients. Sipuleucel-T has been approved for the treatment of asymptomatic or minimally symptomatic mCRPC. Ra-223 has been approved for patients with mCRPC with symptomatic bone metastases (not visceral metastases). Cabazitaxel has been approved as the second line treatment to docetaxel in mCRPC. No differences in the overall survival has been observed between sequences starting with docetaxel versus AA/ENZ. Between AA-to-ENZ and ENZ-to-AA sequence, the AA-to-ENZ sequence appeared to be more favorable than the ENZ-to-AA regarding progression-free survival but not overall survival. Carbazitaxel seemed to retain its activity regardless of the treatment sequence. Of note, ENZ and apalutamide have been approved in non-metastatic CRPC.

A Novel, Circulating Tumor Cell Enrichment Method Reduces ARv7 False Positivity in Patients with Castration-Resistant Prostate Cancer

BACKGROUND

The AR-V7 splice variant is a cause of castration-resistant prostate cancer (CRPC). However, testing for the presence of AR-V7 by real-time polymerase chain reaction (RT-PCR) shows AR-V7 positivity in healthy individuals. We hypothesized that the positivity reflects contamination by hematopoietic cells. We tried a novel circulating tumor cell (CTC) enrichment instrument, using Celsee, to clear hematopoietic cells.

METHODS

We tested whole blood or Celsee-enriched samples for AR-V7 by RT-PCR, and included samples from 41 CRPC patients undergoing sequential therapy. We evaluated the associations between AR-V7 status and clinical factors. We evaluated factors affecting AR-V7 positivity.

RESULTS

AR-V7 positivity was lower in Celsee-enriched than in whole blood specimens. AR-V7 and clinical factors did not predict the therapy effectiveness. We found no significant differences in the effectiveness of enzalutamide/abiraterone (Enz/Abi) upon AR-V7 evaluation. All AR-V7 positive patients had resistance to Enz/Abi. Docetaxel (DTX), cabazitaxel (CBZ), and Radium223 treatment showed no significant difference in the treatment effectiveness, regardless of AR-V7 presence. AR-V7 was more frequently positive than Extent of disease (EOD) 2 in cases with bone metastases.

CONCLUSION

Celsee CTC enrichment suppresses AR-V7 false positivity. All AR-V7 positive patients presented resistance to Enz/Abi. DTX, CBZ, and Radium223 were effective and remain treatment options. AR-V7 positivity should progressively appear in patients with advanced bone metastases.

The role of adrenal derived androgens in castration resistant prostate cancer

Castration resistant prostate cancer (CRPC) remains androgen dependant despite castrate levels of circulating testosterone following androgen deprivation therapy, the first line of treatment for advanced metstatic prostate cancer. CRPC is characterized by alterations in the expression levels of steroidgenic enzymes that enable the tumour to derive potent androgens from circulating adrenal androgen precursors. Intratumoral androgen biosynthesis leads to the localized production of both canonical androgens such as 5α-dihydrotestosterone (DHT) as well as less well characterized 11-oxygenated androgens, which until recently have been overlooked in the context of CRPC. In this review we discuss the contribution of both canonical and 11-oxygenated androgen precursors to the intratumoral androgen pool in CRPC. We present evidence that CRPC remains androgen dependent and discuss the alterations in steroidogenic enzyme expression and how these affect the various pathways to intratumoral androgen biosynthesis. Finally we summarize the current treatment strategies for targeting adrenal derived androgen biosynthesis.