Synergistic Effect of Statins and Abiraterone Acetate on the Growth Inhibition of Neuroblastoma via Targeting Androgen Receptor

Neuroblastoma is the most common extracranial neuroendocrine tumor in childhood. Although many studies have tried to find effective treatments, there are still numerous limitations in current clinical targeted therapy. So, it is important to find new therapeutic targets and strategies from a new perspective. Our previous study reported that the androgen receptor (AR) promotes the growth of neuroblastoma in vitro and in vivo. Based on documentary investigation, we postulated that the AR–SCAP–SREBPs-CYP17/HMGCR axis may regulate cholesterol and androgens synthesis and form a positive enhancement loop promoting NB progression. Clinical samples and Oncomine database analysis proved the activation of AR–SCAP–SREBPs-CYP17/HMGCR axis in neuroblastoma. The combination of inhibitors of HMGCR (statins) and CYP17A1 (abiraterone acetate) showed synergistic effect that significantly inhibited the proliferation and migration with decreased expression of related genes detected in vitro and in vivo suggesting the dual-targeted therapy had the potential to inhibit the progression of neuroblastoma in spite of its MYCN status. This study provides new ideas for clinical treatment of neuroblastoma with efficacy and reduced toxicity.

Recent trend of androgen deprivation therapy in newly diagnosed prostate cancer patients: Comparing between high- and middle-income Asian countries

The number of newly diagnosed prostate cancer cases varies across Asia, with higher mortality‐to‐incidence ratio reported in developing nations. Androgen deprivation therapy (ADT), alone or in combination, remains the mainstay of first‐line treatment for advanced prostate cancer. Key findings of extensive research and randomized controlled trials have shaped current clinical practice and influenced clinical guideline recommendations. We describe here the recent trend of ADT in newly diagnosed prostate cancer for Asia focusing on Japan (high‐income country) and Malaysia (middle‐income country) based on the Asian Prostate Cancer (A‐CaP) Study. The combination of radiotherapy and ADT or ADT alone was common in patients with intermediate‐to‐high risk localized and locally advanced disease. For metastatic prostate cancer, maximum androgen blockade (gonadotrophin‐releasing hormone [GnRH] agonist/antagonist plus antiandrogen) was prevalent among the Japanese patients while primary ADT alone with GnRH agonist/antagonist was widely practiced in the Malaysian cohort. Upfront combined therapy (ADT plus docetaxel or androgen receptor pathway inhibitor) has significantly improved the outcomes of patients with metastatic castration‐naïve prostate cancer. Its application, however, remains low in our cohorts due to patients’ financial capacity and national health insurance coverage. Early detection remains the cornerstone in prostate cancer control to improve treatment outcome and patient survival.

Targeting backdoor androgen synthesis through AKR1C3 inhibition: A presurgical hormonal ablative neoadjuvant trial in high-risk localized prostate cancer

BACKGROUND

Localized prostate cancers (PCs) may resist neoadjuvant androgen receptor (AR)-targeted therapies as a result of persistent intraprostatic androgens arising through upregulation of steroidogenic enzymes. Therefore, we sought to evaluate clinical effects of neoadjuvant indomethacin (Indo), which inhibits the steroidogenic enzyme AKR1C3, in addition to combinatorial anti-androgen blockade, in men with high-risk PC undergoing radical prostatectomy (RP).

METHODS

This was an open label, single-site, Phase II neoadjuvant trial in men with high to very-high-risk PC, as defined by NCCN criteria. Patients received 12 weeks of apalutamide (Apa), abiraterone acetate plus prednisone (AAP), degarelix, and Indo followed by RP. Primary objective was to determine the pathologic complete response (pCR) rate. Secondary objectives included minimal residual disease (MRD) rate, defined as residual cancer burden (RCB) ≤ 0.25cm³ (tumor volume multiplied by tumor cellularity) and elucidation of molecular features of resistance.

RESULTS

Twenty patients were evaluable for the primary endpoint. Baseline median prostate-specific antigen (PSA) was 10.1 ng/ml, 4 (20%) patients had Gleason grade group (GG) 4 disease and 16 had GG 5 disease. At RP, 1 (5%) patient had pCR and 6 (30%) had MRD. Therapy was well tolerated. Over a median follow-up of 23.8 months, 1 of 7 (14%) men with pathologic response and 6 of 13 (46%) men without pathologic response had a PSA relapse. There was no association between prostate hormone levels or HSD3B1 genotype with pathologic response.

CONCLUSIONS

In men with high-risk PC, pCR rates remained low even with combinatorial AR-directed therapy, although rates of MRD were higher. Ongoing follow-up is needed to validate clinical outcomes of men who achieve MRD.

Herb-drug interactions between androgenic Chinese herbal medicines and androgen receptor antagonist on tumor growth: Studies on two xenograft prostate cancer animal models

Our previous study revealed that Epimedii Folium (EF) and Codonopsis Radix (CNR) significantly promoted tumor growth on a subcutaneous mouse model of prostate cancer (PCa) via enhancing the mRNA and protein expressions of androgen receptor (AR), while Astragali Radix (AGR) inhibited tumor growth via suppressing the protein expression of AR. In the present study, we aimed to investigate the potential interactions between EF, CNR or AGR and AR antagonist (abiraterone acetate [ABI]) on the tumor growth using subcutaneous and orthotopic PCa mouse models. EF, CNR, AGR and ABI were intragastrically given to mice once every 2 days for 4 weeks. The pharmacokinetics of ABI were evaluated in the plasma of rats when combined with EF, CNR, or AGR. Our results demonstrated that EF or CNR could weaken the anti-tumor effects of ABI via increasing the AR expression involving activation of the PI3K/AKT and Rb/E2F pathways and decreasing the bioavailability of ABI, while AGR could enhance the anti-tumor effects of ABI through suppressing the AR expression via inhibiting the activations of PI3K/AKT and Rb/E2F pathways and increasing the bioavailability of ABI. These findings imply that cautions should be exercised when prescribing EF and CNR for PCa patients.

Medication patterns of abiraterone acetate plus prednisone or enzalutamide and PSA progression in veterans with metastatic castration-resistant prostate cancer

OBJECTIVES

To quantify the association between dose reductions of abiraterone acetate plus prednisone (AAP) or enzalutamide and prostate-specific antigen (PSA) progression in patients with metastatic castration-resistant prostate cancer (mCRPC). Changes in medication-taking patterns of AAP or enzalutamide may arise due to clinical (e.g. toxicity) and non-clinical (e.g. patient compliance) reasons in men with mCRPC. However, it is unclear how this affects PSA progression.

METHODS

Veterans Health Administration electronic health record database was used to identify Veterans diagnosed with prostate cancer who initiated AAP or enzalutamide (index) from April 2010 to December 2016. PSA progression was defined as the first rise in PSA of ≥2 ng/mL and ≥25% above nadir. The relative dose intensity (RDI) was defined as the ratio of the total dispensed dose over the last two months to the standard recommended dose and was updated monthly. Dose reduction was assessed using a threshold of RDI < 80%.

RESULTS

The cohort included 6069 Veterans aged 74.6 years on average. Mean follow-up was 12.3 months. PSA progression occurred in 62.7% of patients. About 63.6% of AAP- and 67.2% of enzalutamide-treated patients had ≥1 occurrence of RDI <80%. RDI <80% was associated with an 8.8% higher risk of PSA progression (hazard ratio [HR] = 1.088; p = .019; 95% confidence interval [CI] [1.014; 1.166]).

CONCLUSIONS

Dose reduction was observed in most patients and was associated with significantly higher risk of PSA progression in men with mCRPC. These results suggest future efforts to minimize dose reductions for non-clinical reasons are warranted and that patient adherence should be encouraged to limit the risk of PSA progression.

Risk of major adverse cardiovascular events among second-line hormonal therapy for metastatic castration-resistant prostate cancer: A real-world evidence study

BACKGROUND

To evaluate the possible major adverse cardiovascular events (MACE) associated with second-line hormonal therapy in patients with metastatic castration-resistant prostate cancer (mCRPC).

METHODS

We performed a population-based real-world cohort study of 4962 prostate cancer patients between 2014 and 2017 utilizing the Chang Gung Research Database of Taiwan. The second-line hormonal therapies included enzalutamide and abiraterone acetate. The outcomes of interest were MACE, including acute coronary syndrome (ACS), ischemic stroke (IS), and heart failure (HF) events that resulted in hospitalization. Cox proportional-hazards models with inverse probability of treatment weighting (IPTW) with propensity scores were used.

RESULTS

After IPTW, 288 patients were prescribed second-line hormonal therapy and 1575 received first-line androgen-deprivation therapy (ADT). Of all patients diagnosed with MACE, the event rates were 2.92% in the second-line hormonal group and 2.22% in the first-line ADT group. The mean follow-up period was 9.52 months for the second-line hormonal group. Patients who received second-line hormonal therapy exhibited a significantly increased risk for MACE (hazard ratio [HR]: 3.15; 95% confidence interval [CI]: 2.03-4.89), ACS (HR: 4.94; 95% CI: 2.36-10.33), and HF (HR: 2.83; 95% CI: 1.53-5.25), compared with the first-line ADT group, but a similar risk for IS was observed in both groups (HR: 1.70; 95% CI: 0.95-3.04).

CONCLUSIONS

The real-world evidence study revealed increased risks for MACE in mCRPC patients receiving second-line hormonal therapy.

Early Prostate-Specific Antigen (PSA) Change at Four Weeks of the First-Line Treatment Using Abiraterone and Enzalutamide Could Predict Early/Primary Resistance in Metastatic Castration-Resistant Prostate Cancer

Simple Summary

Serum prostate-specific antigen (PSA) level is the most valuable biomarker in prostate cancer. This study investigates the predictive value of achieving >30% PSA decline at four weeks of first-line androgen signaling inhibitors (ASIs) using a multi-institutional cohort dataset of 254 mCRPC patients. The achievement of >30% PSA decline at four weeks is an independent predictor for overall survival (OS). Interestingly, in patients who did not achieve >30% PSA decline at four weeks—an achievement of the >30% PSA decline at 12 weeks is eventually observed in 30.9% of those patients. To identify the variables that discriminate the patient survival in 97 patients without achieving >30% PSA decline at four weeks of the first-line treatment, a multivariate analysis is conducted. The duration of androgen deprivation therapy before CRPC < 12 months and Eastern Cooperative Oncology Group Performance Status ≥ 1 are identified as independent predictors for shorter OS for those patients.

Abstract

The identification of early or primary resistance to androgen signaling inhibitors (ASIs) is of great value for the treatment of metastatic castration-resistant prostate cancer (mCRPC). This study evaluates the predictive value of prostate-specific antigen (PSA) response at dour weeks of first-line ASIs treatment for mCRPC patients. A total of 254 patients treated with ASIs (abiraterone acetate: AA and enzalutamide: Enz) at the first-line treatment are retrospectively analyzed. Patients are stratified according to the achievement of >30% PSA decline at 4 and 12 weeks from the treatment initiation. At four weeks of the treatment, 157 patients (61.8%) achieved >30% PSA decline from the baseline. Thereafter, 177 patients (69.7%) achieved >30% PSA decline at 12 weeks of the treatment. A multivariate analysis exhibits >30% PSA decline at four weeks as an independent predictor for overall survival (OS). We note that 30 of 97 (30.9%) patients who did not achieve >30% PSA decline at four weeks consequently achieved >30% PSA decline at 12 weeks, and had a comparable favorable three years OS rate as the 147 patients achieving >30% PSA decline at both 4 and 12 weeks. To identify the variables that discriminate the patient survival in 97 patients without achieving >30% PSA decline at four weeks, a multivariate analysis is performed. The duration of androgen deprivation therapy before CRPC ≤ 12 months and Eastern Cooperative Oncology Group Performance Status ≥ 1 are identified as independent predictors for shorter OS for those patients. These data offer a concept of early treatment switch after four weeks of first-line ASIs when not observing >30% PSA decline at four weeks—particularly in patients with a modest effect of ADT and poor performance status.

Pulmonary metastasis secondary to abiraterone-resistant prostate cancer with homozygous deletions of BRCA2: First Japanese case

INTRODUCTION

Most metastatic prostate cancers acquire the capacity for androgen-independent growth and become resistant to androgen deprivation therapy. A patient-focused treatment strategy is needed for aggressive castration-resistant prostate cancer.

CASE PRESENTATION

We report the case of a 62-year-old man who presented with prostatic adenocarcinoma who was treated by radiation and combined androgen blockade. After completion of first-line therapy, he was diagnosed with multiple metastatic castration-resistant prostate cancer in the lung. Second-line therapy with abiraterone acetate resulted in partial remission of the lung metastases. Thoracic surgery was performed to remove the single lung metastasis remaining. Next-generation sequencing of the specimens demonstrated homozygous loss of BRCA2. We note in this case a heterogeneous response to abiraterone acetate may be related to the somatic BRCA2 deletions.

CONCLUSIONS

We present the first Japanese case of a metastatic abiraterone acetate-resistant castration-resistant prostate cancer accompanied by BRCA2 mutation.

Abiraterone acetate in combination with androgen deprivation therapy compared to androgen deprivation therapy only for metastatic hormone-sensitive prostate cancer

BACKGROUND

Systemic androgen deprivation therapy (ADT), also referred to as hormone therapy,àhas long been the primary treatment for metastatic prostate cancer. Additional agents have been reserved for the castrate-resistant disease stage when ADT start becoming less effective. Abiraterone is an agent with an established role in that disease stage, which has only recently been evaluated in the hormone-sensitive setting.

OBJECTIVES

To assess the effects of early abiraterone acetate, in combination with systemic ADT, for newly diagnosed metastatic hormone-sensitive prostate cancer.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, six other databases, two trials registries, grey literature, and conference proceedings, up to 15 May 2020. We applied no restrictions on publication language or status.

SELECTION CRITERIA

We included randomized trials, in which men diagnosed with hormone-sensitive prostate cancer were administered abiraterone acetate and prednisolone with ADT or ADTàalone.

DATA COLLECTION AND ANALYSIS

Two review authors independently classified studies and abstracted data from the included studies. We performed statistical analyses using a random-effects model. We rated the quality of evidence according to the GRADE approach.

MAIN RESULTS

The search identified two randomized controlled trials (RCT), with 2201 men, who were assigned to receive either abiraterone acetate 1000 mg once daily and low dose prednisone (5mg) in addition to ADT, or ADT alone. In the LATITUDE trial, the median age and range of men in the intervention group was 68 (38 to 89) years, and 67 (33 to 92) years in the control group. Nearly all of the men in thisàstudy (97.6%) had prostate cancer with a Gleason score of at least 8 (ISUP grade group 4). Primary outcomes The addition of abiraterone acetate to ADT reduces the probability of death from any cause compared to ADT alone (hazard ratio [HR] 0.64, 95% confidence interval [CI] 0.56 to 0.73; 2 RCTs, 2201 men; high certainty of evidence); this corresponds to 163 fewer deaths per 1000 men with hormone-sensitive metastaticàprostate cancerà(210 fewer to 115 fewer) at five years. Abiraterone acetate in addition to ADT probably results in little to no differenceàin quality of life compared to ADT alone, measured with the Functional Assessment of Cancer Therapy-prostate total score (FACT-P; range 0 to 156; higher values indicates better quality of life),àat 12 months (mean difference [MD] 2.90 points, 95% CI 0.11 to 5.60; 1 RCT, 838 men; moderate certainty of evidence). Secondary outcomes Abiraterone plus ADT increases the risk of grades III to V adverse events compared to ADT alone (risk ratio [RR] 1.34, 95% CI 1.22 to 1.47; 1 RCT, 1199 men; high certainty of evidence); this corresponds to 162 more grade III to Vàevents per 1000 men with hormone-sensitive metastaticàprostate cancerà(105 more to 224 more) at a median follow-up of 30àmonths. Abiraterone acetate in addition to ADT probably reduces the probability of death due to prostate cancer compared to ADT alone (HR 0.58, 95% CI 0.50 to 0.68; 2 RCTs, 2201 men; moderate certainty of evidence). This corresponds to 120 fewer death from prostate cancer per 1000 men with hormone-sensitive metastaticàprostate cancerà(95% CI 145 fewer to 90 fewer) afteràa median follow-up of 30 months. The addition of abiraterone acetate to ADT probably decreases the probability of disease progression compared to ADT alone (HR 0.35, 95%CI 0.26 to 0.49; 2 RCTs, 2097 men; moderate certainty of evidence). This corresponds to 369 fewer incidences of disease progression per 1000 men with hormone-sensitive metastaticàprostate cancerà(456 fewer to 256 fewer)àafter a median follow-up of 30 months. The addition of abiraterone acetate to ADT probably increases the risk of discontinuing treatment due to adverse events compared to ADT alone (RR 1.50, 95% CI 1.17 to 1.92; 1 RCT, 1199 men; moderate certainty of evidence). This corresponds to 51 more men (95% CI 17 more to 93 more) discontinuing treatment because of adverse events per 1000 men treated with abiraterone acetate and ADT compared to ADT alone afteràa median follow-up of 30 months.

AUTHORS' CONCLUSIONS

The addition of abiraterone acetate to androgen deprivation therapy improves overall survival but probably not quality of life. Itàprobably also extends disease-specific survival, and delays disease progression compared to androgen deprivation therapy alone. However, the risk of grades III to V adverse events is increased, and probably, so is the risk of discontinuing treatment due to adverse events.

Effectiveness of abiraterone acetate plus prednisone in chemotherapy-naïve patients with metastatic castration-resistant prostate cancer in a large prospective real-world cohort: the ABItude study

Background:

Real-world data on chemotherapy-naïve patients with metastatic castration-resistant prostate cancer (mCRPC) treated with abiraterone plus prednisone are limited, largely deriving from small retrospective studies.

Methods:

ABitude is an Italian, observational, prospective, multicenter study of mCRPC patients receiving abiraterone plus prednisone in clinical practice. Chemotherapy-naïve mCRPC patients were consecutively enrolled at abiraterone start (February 2016 to June 2017) and are being followed for 3 years, with evaluation approximately every 6 months. Several clinical and patients reported outcomes were examined.

Results:

In this second interim analysis, among 481 enrolled patients, 453 were evaluable for analyses. At baseline, the median age was 77 years and ~69% of patients had comorbidities (mainly cardiovascular diseases). Metastases were located mainly at bones and lymph nodes; 8.4% of patients had visceral metastases. During a median follow-up of 18 months, 1- and 2-year probability of radiographic progression-free survival were 73.9% and 56.2%, respectively; the corresponding rates for overall survival were 87.3% and 70.4%. In multivariable analyses, the number of bone metastases significantly affected radiographic progression-free survival and overall survival. During abiraterone plus prednisone treatment, 65% of patients had a ⩾50% prostate-specific antigen decline, and quality of life remained appreciably high. Among symptomatic patients according to the Brief Pain Inventory) (32%), scores significantly declined after 6 months of treatment. Overall, eight patients (1.7%) had serious adverse reactions to abiraterone.

Conclusions:

Abiraterone plus prednisone is effective and safe for chemotherapy-naïve mCRPC patients in clinical practice.

Intracrine androgen biosynthesis and drug resistance

Castration-resistant prostate cancer is the lethal form of prostate cancer and most commonly remains dependent on androgen receptor (AR) signaling. Current therapies use AR signaling inhibitors (ARSI) exemplified by abiraterone acetate, a P450c17 inhibitor, and enzalutamide, a potent AR antagonist. However, drug resistance to these agents occurs within 12-18 months and they only prolong overall survival by 3-4 months. Multiple mechanisms can contribute to ARSI drug resistance. These mechanisms can include but are not limited to germline mutations in the AR, post-transcriptional alterations in AR structure, and adaptive expression of genes involved in the intracrine biosynthesis and metabolism of androgens within the tumor. This review focuses on intracrine androgen biosynthesis, how this can contribute to ARSI drug resistance, and therapeutic strategies that can be used to surmount these resistance mechanisms.

Plasma AR Copy Number Changes and Outcome to Abiraterone and Enzalutamide

Introduction: Plasma androgen receptor (AR) copy number (CN) status identifies castration-resistant prostate cancer (CRPC) patients with worse outcome on abiraterone/enzalutamide. However, the impact of AR CN changes on clinical outcome in CRPC is unknown.

Materials and Methods: Plasma samples from 73 patients treated with abiraterone or enzalutamide were collected at baseline and at the time of progression disease (PD). Droplet digital polymerase chain reaction was used to assess AR CN status.

Results: We showed that 11 patients (15.1%) changed AR CN status from baseline to PD (9 patients from normal to gain, 2 from gain to normal). Patients changing AR CN status from normal at baseline to gain at PD had intermediate median overall survival (OS) of 20.5 months (95% CI = 8.0–44.2) between those who remained AR CN normal from baseline to PD (27.3 months [95% CI = 21.9–34.4]) and those who remained AR CN gain from baseline to PD (9.1 months [95% CI = 3.8–14.5], p < 0.0001). Patients changing AR CN from normal at baseline to gain at PD had a median progression-free survival (PFS) of 9.2 months (95% CI = 2.0–14.7), patients who remained AR CN normal had a median PFS of 9.1 months (95% CI = 7.2–10.1), and patients who remained AR CN gain had a median PFS of 5.4 (95% CI = 3.6–6.5, p = 0.0005). Both OS and PFS were not significantly different between patients with AR CN that changes from normal to gain and patients with stable AR CN normal.

Conclusions: We showed that CRPC patients changing AR CN status from baseline to progression time point had intermediate OS and we suggested that AR CN evaluation at baseline could be the most informative for clinical outcome of CRPC patients treated with abiraterone or enzalutamide. Larger prospective studies are warranted.

Adherence Measures for Patients with Metastatic Castration-Resistant Prostate Cancer Treated with Abiraterone Acetate plus Prednisone: Results of a Prospective, Cluster-Randomized Trial

Simple Summary

We report the final results of a multicenter, prospective, 2-arm trial in a real world setting for patients with metastatic castration resistant prostate cancer. A number of 675 patients were allocated by center-based cluster-randomization to arm A with adherence enhancing measures or arm B without adherence enhancing measures. Our study reveals a generally high medication adherence in patients with mCRPC with no clear difference between Arm A and Arm B. Our results confirm the benefit of Abiraterone acetate plus Prednisolone in terms of effectiveness and quality of life in a real world setting.

Abstract

Residual androgen production causes tumor progression in metastatic, castration-resistant prostate cancer (mCRPC) patients. Abiraterone acetate (AA), a prodrug of abiraterone, is an oral CYP-17 inhibitor that blocks androgen production. It was hypothesized that adherence-enhancing measures (AEM) might be beneficial for mCRPC patients receiving abiraterone acetate plus prednisone (AA + P). This multicenter, prospective, 2-arm trial allocated mCRPC patients who were progressive after docetaxel-based chemotherapy or asymptomatic/mildly symptomatic after failure of an androgen deprivation therapy to Arm A (with AEM) or Arm B (without AEM) by center-based cluster-randomization. The primary objective was to assess the influence of AEM on discontinuation rates and medication adherence in mCRPC patients treated with AA + P. A total of 360 patients were allocated to Arm A, and 315 patients to Arm B. At month 3, the rate of treatment discontinuation, not due to disease progression or the start of new cancer therapy, was low in both arms (A: 9.0% vs. B: 7.3%, OR = 1.230). Few patients had a medium/low Morisky Medication Adherence Scale (MMAS-4) score (A: 6.4% vs. B: 9.1%, OR = 0.685). The results obtained did not suggest any clear adherence difference between Arm A and Arm B. In patients with mCRPC taking AA + P medication, adherence seemed to be generally high.

Second-Generation Antiandrogen Therapy Radiosensitizes Prostate Cancer Regardless of Castration State through Inhibition of DNA Double Strand Break Repair

(1) Background: The combination of the first-generation antiandrogens and radiotherapy (RT) has been studied extensively in the clinical setting of prostate cancer (PCa). Here, we evaluated the potential radiosensitizing effect of the second-generation antiandrogens abiraterone acetate, apalutamide and enzalutamide. (2) Methods: Cell proliferation and agarose-colony forming assay were used to measure the effect on survival. Double strand break repair efficiency was monitored using immunofluorescence staining of γH2AX/53BP1. (3) Results: We report retrospectively a minor benefit for PCa patients received first-generation androgen blockers and RT compared to patients treated with RT alone. Combining either of the second-generation antiandrogens and 2Gy suppressed cell growth and increased doubling time significantly more than 2Gy alone, in both hormone-responsive LNCaP and castration-resistant C4-2B cells. These findings were recapitulated in resistant sub-clones to (i) hormone ablation (LNCaP-abl), (ii) abiraterone acetate (LNCaP-abi), (iii) apalutamide (LNCaP-ARN509), (iv) enzalutamide (C4-2B-ENZA), and in castration-resistant 22-RV1 cells. This radiosensitization effect was not observable using the first-generation antiandrogen bicalutamide. Inhibition of DNA DSB repair was found to contribute to the radiosensitization effect of second-generation antiandrogens, as demonstrated by a significant increase in residual γH2AX and 53BP1 foci numbers at 24h post-IR. DSB repair inhibition was further demonstrated in 22 patient-derived tumor slice cultures treated with abiraterone acetate before ex-vivo irradiation with 2Gy. (4) Conclusion: Together, these data show that second-generation antiandrogens can enhance radiosensitivity in PCa through DSB repair inhibition, regardless of their hormonal status. Translated into clinical practice, our results may help to find additional strategies to improve the effectiveness of RT in localized PCa, paving the way for a clinical trial.

Efficacy and safety of abiraterone acetate plus prednisone in Japanese patients with newly diagnosed, metastatic hormone-naive prostate cancer: final subgroup analysis of LATITUDE, a randomized, double-blind, placebo-controlled, phase 3 study

Background

LATITUDE was a randomized, double-blind, international and phase 3 study of abiraterone acetate plus prednisone in patients with high-risk metastatic hormone-naïve prostate cancer. In the first interim analysis of LATITUDE (clinical cutoff date: 31 October 2016), significant prolongation in overall survival and radiographic progression-free survival (co-primary endpoints) was observed when compared with placebo. The results of the Japanese subgroup analysis of LATITUDE first interim analysis were consistent with those of the overall population. In this study, overall survival and safety results from the final analysis of the Japanese subgroup of the LATITUDE study are presented (clinical cutoff date: 15 August 2018).

Methods

Abiraterone acetate (1000 mg/day) and prednisone (5 mg/day) were administered orally in the abiraterone acetate plus prednisone group, and matching placebos in the placebo group.

Results

Of the 1199 patients included in LATITUDE, 70 constituted the Japanese subgroup (abiraterone acetate plus prednisone: n = 35, placebo: n = 35). Following a median (range) follow-up of 56.6 (2.5, 64.2) months, the median overall survival was not reached in both the treatment arms of the Japanese subgroup (hazard ratio: 0.61; 95% confidence interval: 0.27–1.42; nominal P = 0.2502). A total of 23 deaths (abiraterone acetate plus prednisone: 9 [25.7%], placebo group: 14 [40.0%]) were reported in Japanese subgroup. Grade 3/4 adverse events were reported in 24 (68.6%) and 9 (25.7%) patients in the abiraterone acetate plus prednisone and placebo groups, respectively.

Conclusions

In this Japanese subgroup analysis, addition of abiraterone acetate plus prednisone to androgen-deprivation therapy demonstrated favorable efficacy and safety outcomes in patients with newly diagnosed, high-risk metastatic hormone-naïve prostate cancer. Survival benefits observed in the Japanese subgroup first interim analysis were sustained long-term and were consistent with the overall population.

YB-1 variant and androgen receptor axis-targeted agents in metastatic castration-resistant prostate cancer patients

Aim: To evaluate the influence of YB-1 rs10493112 variant as a genetic marker for response to second-generation androgen receptor axis-target agents. Methods: A hospital-based cohort study of 78 patients with metastatic castration-resistant prostate cancer was conducted. Genotyping was performed by TaqMan^® allelic discrimination technology. Main results: In abiraterone-treated and high-risk patients, YB-1 rs10493112 AA genotype carriers showed lower progression-free survival than C allele genotype patients (4 vs 17 months; p = 0.009). For carriers of AA genotype, multivariate Cox regression analysis revealed a fivefold increased risk of progression (p = 0.035). Conclusion: The study findings suggest that, for metastatic and castration-resistant prostate cancer patients, this polymorphism might be a putative marker for the clinical outcome.

Expert recommendations on the management of patients with metastatic castration-resistant prostate cancer who progress after CHAARTED or LATITUDE

Objective

Our aim was to provide practical recommendations on the management of patients with metastatic castration-resistant prostate cancer (mCRPC) who have progressed after docetaxel plus androgen-deprivation therapy (ADT) or abiraterone plus ADT.

Methods

Systematic literature review (SLR), nominal group meeting, and Delphi process. A panel of 12 experts was established who defined the scope, users, and sections of the document. We performed an SLR in order to assess the efficacy and safety of available drugs in patients with mCRPC. Abstracts from the American Society of Oncology and European Society for Medical Oncology meetings were also examined. The results were discussed during an expert meeting in which 14 recommendations were generated. The level of agreement with the recommendations was also tested by 13 additional experts following the Delphi process. Recommendations were voted by means of scores ranging from 0 (total disagreement) to 10 (total agreement). We defined agreement when at least 70% of the experts voted ⩾7. Next, we assigned a level of evidence and grade to the recommendation using the Oxford Centre for Evidence-based Medicine Levels of Evidence, following which the final document was drafted.

Results

The literature search did not find any articles meeting the inclusion criteria. Finally, 13 out of 14 recommendations were accepted after two Delphi rounds (two were modified after the first round). They pertain to general and individual case-based treatment recommendations.

Conclusions

In mCRPC patients who have progressed after docetaxel or abiraterone plus ADT in the metastatic hormone-sensitive prostate cancer setting, these recommendations may support treatment decision-making, due to the lack of evidence or other globally accepted sequencing algorithms.

Clinical activity of abiraterone plus prednisone in docetaxel-naοve and docetaxel-resistant Chinese patients with metastatic castration-resistant prostate cancer

This study investigated the clinical activity of abiraterone plus prednisone in docetaxel-naïve and docetaxel-resistant Chinese patients with metastatic castration-resistant prostate cancer (mCRPC). A total of 146 patients with docetaxel-naïve group (103 cases) and docetaxel-resistant group (43 cases) were enrolled from the Shanghai Cancer Center (Shanghai, China) in this retrospective cohort study. The efficacy endpoints were prostate-specific antigen response rate, prostate-specific antigen progression-free survival, clinical/radiographic progression-free survival, and overall survival in response to abiraterone plus prednisone. Significantly higher prostate-specific antigen response rate was found in docetaxel-naïve group (54.4%, 56/103) compared to docetaxel-resistant group (34.9%, 15/43) (P = 0.047). In addition, significantly higher median prostate-specific antigen progression-free survival (14.0 vs 7.7 months, P = 0.005), clinical or radiographic progression-free survival (17.0 vs 12.5 months, P = 0.003), and overall survival (27.0 vs 18.0 months, P = 0.016) were found in docetaxel-naïve group compared to docetaxel-resistant group, respectively. The univariate and multivariate analyses indicated that lower albumin and visceral metastases were independent significant predictors for shorter overall survival. To sum up, our data suggested that abiraterone plus prednisone was efficient in both docetaxel-naïve and docetaxel-resistant Chinese patients. Moreover, higher PSA response rate and longer overall survival were observed in the docetaxel-naïve group, which suggested that abiraterone was more effective for docetaxel- naïve patients than for docetaxel failures.

Abiraterone acetate treatment lowers 11-oxygenated androgens

CONTEXT

The human adrenal is the dominant source of androgens in castration-resistant prostate cancer (CRPC) and classic 21-hydroxylase deficiency (21OHD). Abiraterone, derived from the prodrug abiraterone acetate (AA), inhibits the activity of cytochrome P450 17-hydroxylase/17,20-lyase (CYP17A1), the enzyme required for all androgen biosynthesis. AA treatment effectively lowers testosterone and androstenedione in 21OHD and CRPC patients. The 11-oxygenated androgens are major adrenal-derived androgens, yet little is known regarding the effects of AA administration on 11-oxygenated androgens.

OBJECTIVE

To test the hypothesis that AA therapy decreases 11-oxygenated androgens.

DESIGN

Samples were obtained from 21OHD or CRPC participants in AA or AA plus prednisone (AAP)-treatment studies, respectively.

METHODS

We employed liquid chromatography-tandem mass spectrometry (LC-MS/MS) to measure the 11-oxygenated androgens, 11β-hydroxyandrostenedione, 11-ketoandrostenedione, 11β-hydroxytestosterone, and 11-ketotestosterone, in plasma or serum samples from six 21OHD and six CRPC patients before and after treatment with AA or AAP, respectively.

RESULTS

In CRPC patients, administration of AAP (1000 mg/day AA with prednisone and medical castration) lowered all four 11-oxygenated androgens to below the lower limits of quantitation (<0.1-0.3 nmol/L), equivalent to 64-94% reductions from baseline. In 21OHD patients, administration of AA (100-250 mg/day for 6 days) reduced all 11-oxygenated androgens by on average 56-77% from baseline.

CONCLUSIONS

We conclude that AA and AAP therapies markedly reduce the production of the adrenal-derived 11-oxygenated androgens, both in patients with high (21OHD) or normal (CRPC) 11-oxygenated androgens at baseline, respectively. Reduction of 11-oxygenated androgens is an important aspect of AA and AAP pharmacology.

Real-world incidence and burden of adverse events among non-metastatic prostate cancer patients treated with secondary hormonal therapies following androgen deprivation therapy

Aims: To describe the incidence and identify prognostic factors of central nervous system (CNS) adverse events (AEs) and any AEs (CNS, skin rash, or fracture) and evaluate the healthcare resource utilization (HCRU), direct medical costs, and therapy discontinuation associated with these AEs among non-metastatic prostate cancer (nmPC) patients who received secondary hormone therapies.Methods and results: nmPC patients who had initiated secondary hormonal therapy with enzalutamide, bicalutamide, or abiraterone ≥1 year after androgen deprivation therapy (ADT) were identified in the MarketScan database. Survival analyses were used to describe the incidence of CNS or any AEs. Annual HCRU and costs were compared across patient groups (CNS AE vs no CNS AE; any AE vs no AE) using propensity score weighted generalized linear models. Multivariate Cox proportional hazards models were used to identify AE predictors and compare risks of discontinuation.Results: The analysis included 532 patients who initiated secondary hormonal therapies, among whom 201 (38%) and 244 (46%) experienced a CNS AE and any AE, respectively. Median times to CNS AE and any AE from therapy initiation were 17.90 and 11.00 months, respectively. Predictors of any AE were any AE in the baseline period (≤6 months before starting therapy), Charlson Comorbidity Index (CCI) score (1 vs 0), surgical castration, and older age. Predictors of CNS AEs were CNS AE in the baseline period and CCI score (1 vs 0). CNS and any AEs were associated with significantly higher HCRU. CNS AEs were associated with significantly higher incremental total medical costs ($18,522). CNS AEs and any AEs significantly increased therapy discontinuation risk by 48% and 38%, respectively.Conclusions: AEs increase the economic burden and therapy discontinuation among nmPC patients receiving secondary hormonal therapies subsequent to ADTs. These patients should be carefully evaluated for AEs to reduce therapy discontinuation, HCRU, and direct medical costs.

Supersaturated-Silica Lipid Hybrids Improve in Vitro Solubilization of Abiraterone Acetate

PURPOSE

Abiraterone acetate (AbA) is a poorly water-soluble drug with an oral bioavailability of <10% and a significant pharmaceutical food effect. We aimed to develop a more efficient oral solid-state lipid-based formulation for AbA using a supersaturated silica-lipid hybrid (super-SLH) approach to achieve high drug loading, improve in vitro solubilization and mitigate the food effect, while gaining a mechanistic insight into how super-SLH are digested and release drug.

METHODS

The influence of super-SLH saturation level and lipid type on the physicochemical properties and in vitro solubilization during lipolysis of the formulations was investigated and compared to the commercial product, Zytiga.

RESULTS

Super-SLH achieved significantly greater levels of AbA solubilization compared to Zytiga. Solubilization was influenced by the AbA saturation level, which determined the solid state of AbA and the relative amount of lipid, and the lipid utilized, which determined its degree of digestion and the affinity of the lipid and digestion products to the silica. A fine balance existed between achieving high drug loads using supersaturation and improving performance using the lipid-based formulation approach. The non-supersaturated SLH prepared with Capmul PG8 mitigated the 3-fold in vitro food effect.

CONCLUSION

SLH and super-SLH improve in vitro solubilization of AbA, remove the food effect and demonstrate potential to improve oral bioavailability in vivo. Graphical Abstract Abiraterone acetate was formulated as silica-lipid hybrids and demonstrated enhanced in vitro solubilization in comparison to pure abiraterone acetate and commercial product, Zytiga.

Analysis of AR-FL and AR-V1 in Whole Blood of Patients with Castration Resistant Prostate Cancer as a Tool for Predicting Response to Abiraterone Acetate

PURPOSE

Reliable molecular diagnostic tools are still unavailable for making informed treatment decisions and monitoring the response in patients with castration resistant prostate cancer. We evaluated the significance of whole blood circulating androgen receptor transcripts of full length (AR-FL) and splice variants (AR-V1, AR-V3 and AR-V7) as biomarkers of abiraterone acetate treatment resistance in patients with castration resistant prostate cancer.

MATERIALS AND METHODS

After retrospective analysis in 112 prostate specimens AR-FL, AR-V1, AR-V3 and AR-V7 were evaluated in 185 serial blood samples, prospectively collected from 102 patients with castration resistant prostate cancer before and during abiraterone acetate therapy via reverse transcription quantitative polymerase chain reaction.

RESULTS

AR-FL was present in all samples while AR-V1, AR-V3, AR-V7 and at least 1 of them was detected in 17%, 55%, 65% and 81% of castration resistant prostate cancer blood samples, respectively. The highest amount of AR-V1 was found in blood of patients whose response time was short and medium in comparison to extended. Patients with a higher level of AR-FL and/or AR-V1 had the shortest progression-free survival and overall survival (p <0.0001).

CONCLUSIONS

Blood circulating AR-FL or AR-V1 can serve as blood based biomarkers for identification of the primary resistance to abiraterone acetate and the tool to monitor de novo resistance development during abiraterone acetate treatment.

Comparison of Oncologic Outcomes Between Two Alternative Sequences with Abiraterone Acetate and Enzalutamide in Patients with Metastatic Castration-Resistant Prostate Cancer: A Systematic Review and Meta-Analysis

Sequential treatment of androgen receptor axis targeted agents (ARAT), abiraterone acetate (ABI) and enzalutamide (ENZA), in metastatic castration-resistant prostate cancer (mCRPC) demonstrated some positive effects, but cross-resistances between ABI and ENZA that reduce activity have been suggested. Therefore, we conducted a meta-analysis to compare oncologic outcomes between the treatment sequences of ABI-ENZA and ENZA-ABI in patients with mCRPC. The primary endpoint was a combined progression-free survival (PFS), and the secondary endpoint was overall survival (OS). A total of five trials on 553 patients were included in this study. Each of the included studies was retrospective. In two studies including both chemo-naïve and post-chemotherapy mCRPC patients, for ABI-ENZA compared with ENZA-ABI, pooled hazard ratios (HRs) for PFS and OS were 0.37 (p < 0.0001; 95% confidence intervals (CIs), 0.23–0.60) and 0.64 (p = 0.10; 95% CIs, 0.37–1.10), respectively. In three studies with chemo-naïve mCRPC patients only, for ABI-ENZA compared with ENZA-ABI, pooled HRs for PFS and OS were 0.57 (p = 0.02; 95% CIs, 0.35–0.92) and 0.86 (p = 0.39; 95% CIs, 0.61–1.21), respectively. The current meta-analysis revealed that ABI-ENZA had a significantly more favorable oncological outcome, but the level of evidence was low. Therefore, large-scale randomized trials may be needed.

Prognostic factors for patients treated with abiraterone

Aim:

To evaluate prostate-specific antigen response (PSAr) defined as a ≥50% decrease in PSA concentration from the pretreatment value, as a prognostic factor in patients with metastatic castration-resistant prostate cancer (mCRPC) treated with abiraterone acetate (AA).

Methods:

Retrospective evaluation of patients with mCRPC treated with AA.

Results:

124 patients were identified. Median overall survival and progression-free survival for patients achieving PSAr versus patients without PSAr were 29.3 versus 9.7 months and 17.0 versus 5.2 months, respectively. Multivariate analysis confirmed that PSAr correlated with better overall survival (hazard ratio: 0.19; 95% CI: 0.10−0.38; p < 0.001) and progression-free survival (hazard ratio: 0.24; 95% CI: 0.14−0.41; p < 0.001).

Conclusion:

PSAr can be utilized as prognostic and predictive factors in mCRPC patients treated with AA.

Therapeutic options for metastatic castration-resistant prostate cancer are expanding. However, biomarkers with predictive and prognostic value to assist in treatment guidance are lacking. The aim of this study was to evaluate prostate-specific antigen response as a prognostic factor in patients treated with abiraterone acetate. It was possible to confirm that prostate-specific antigen response correlated with better overall survival and progression-free survival in this patient cohort, evidencing the possible role of biochemical markers as surrogates for response and prognosis, especially in diseases that are difficult to evaluate radiographically.

Real-world outcome with abiraterone acetate plus prednisone in Asian men with metastatic castrate-resistant prostate cancer: The Singapore experience

INTRODUCTION

Several small studies have reviewed the efficacy of abiraterone acetate plus prednisolone (AAP) in clinical practice outside a trial setting. We report the largest cohort study of clinical outcomes in metastatic castrate-resistant prostate cancer (mCRPC) patients treated with AAP in a multicenter multiracial clinical setting.

METHODS

A retrospective analysis on mCRPC patients treated at four tertiary hospitals in Singapore from 2012 to 2017 was conducted. Disease characteristics, treatment outcomes, and adverse events were retrieved from electronic medical records. Primary clinical end-point was overall survival (OS). A subset analysis of patients with various variables and OS curves were generated using the Kaplan-Meier method and compared using the log-rank test.

RESULTS

Out of 200 patients with mCRPC treated with AAP, 163 (81.5%) patients were chemo-naïve (CN) and 37 (18.5%) patients were postchemotherapy (PC), with the median age of 68 (34-87) and 65 (52-80) years, respectively. Median OS was 20.0 (95% CI, 18.3-22.9) and 10.5 months (95% CI, 1.1-40.5) for CN and PC cohorts, respectively. A subset analysis of 108 patients showed a significantly longer OS in patients who had prior ADT for more than 12 months in CN patients (P < 0.001). Incidences of G3/G4 events were around 6.6%; most common side effect being hypertension with an incidence of 2.4%.

CONCLUSIONS

Treatment of CN and PC patients with AAP was associated with a comparable OS and progression-free survival to the reported series. Patients who were responsive to prior ADT of 12 months or more were associated with an improved OS.