Cardiovascular events among patients with prostate cancer treated with abiraterone and enzalutamide.

BACKGROUND AND PURPOSE: There is growing concern about the adverse metabolic and cardiovascular effects of abiraterone acetate (AA) and enzalutamide (ENZ), two standard hormonal therapies for prostate cancer. We analysed the risk of cardiovascular adverse events among patients treated with AA and ENZ. PATIENTS AND METHODS: We used Kythera Medicare data from January 2019 to June 2023 to identify patients with at least one pharmacy claim for AA or ENZ. The index date was the first prescription claim date. Patients were required to have 1 year of data pre- and post-index date. New users excluded those with prior AA or ENZ claims and pre-existing cardiovascular comorbidities. Demographic and clinical variables, including age, socioeconomic status (SES), comorbidity score, prostate-specific comorbidities, and healthcare costs, were analysed . Propensity score matching was employed for risk adjustment. RESULTS: Of the 8,929 and 8,624 patients in the AA and ENZ cohorts, respectively, 7,647 were matched after adjusting for age, sociodemographic, and clinical factors. Between the matched cohorts (15.54% vs. 14.83%, p < 0.05), there were no statistically significant differences in any cardiovascular event after adjusting for these factors. The most common cardiovascular event in both cohorts was heart failure (5.20% vs. 4.49%), followed by atrial fibrillation (4.42% vs. 3.60%) and hypotension (2.93% vs. 2.48%). INTERPRETATION: This study provides real-world evidence of the cardiovascular risk of AA and ENZ that may not appear in clinical trial settings. Adjusting for age, baseline comorbidities, and SES, the likelihood of a cardiovascular event did not differ between treatment groups.

Bone-Modifying Agents in Patients With High-Risk Metastatic Castration-Sensitive Prostate Cancer Treated With Abiraterone Acetate.

Importance: The association between the use of bone-modifying agents (BMAs) and the outcomes among patients with metastatic castration-sensitive prostate cancer (mCSPC) treated with abiraterone acetate plus prednisone (AAP) remains unclear. Objective: To investigate the association between BMA use and the outcomes of patients with mCSPC receiving AAP. Design, Setting, and Participants: In this cohort study, a post hoc analysis of individual participant data from the LATITUDE trial was performed. The LATITUDE trial, a phase 3 randomized clinical trial, aimed to assess the efficacy of AAP and androgen deprivation therapy (ADT) vs dual-placebo and ADT in patients with high-risk mCSPC (data cutoff, August 15, 2018). Eligible patients had newly diagnosed prostate cancer with metastases and at least 2 of 3 high-risk factors (Gleason score ≥8, presence of ≥3 lesions on bone scan, or presence of measurable visceral metastasis). The trial was conducted at 235 sites in 34 countries. Data for the present study were evaluated from July 18 to September 23, 2023. Exposures: Use of BMAs was defined as the administration of bisphosphonates and denosumab within 90 days before and after randomization. Main Outcomes and Measures: The primary outcomes were time to skeletal-related events (SREs) and overall survival (OS). An SRE was defined as a clinical or pathological fracture, spinal cord compression, palliative radiation to bone, or surgery involving bone. Differences in these outcomes were examined using the restricted mean survival time from inverse probability of treatment weighting-adjusted Kaplan-Meier curves, estimated until the last event was observed (longest time observed, 63.9 months). Treatment × covariate interactions were analyzed using weighted Cox proportional hazards regression models for the total cohort. Results: In the total cohort of 1199 patients (956 [79.7%] younger than 75 years), 597 (49.8%) received AAP and ADT, including 474 (79.4%) younger than 75 years and 384 (64.3%) with more than 10 bone metastases (AAP cohort); 602 (50.2%) were treated with dual placebo and ADT, including 482 (80.1%) younger than 75 years and 377 (62.6%) with more than 10 bone metastases (ADT cohort). In the AAP cohort, 132 patients (22.1%) received BMAs, while in the ADT cohort, 131 (21.8%) did. Zoledronic acid was the most frequently administered BMA in both the AAP (93 [70.5%]) and the ADT (88 [67.2%]) cohorts. During the median follow-up of 51.8 (IQR, 47.2-57.0) months in the AAP cohort, BMA use was associated with a longer time to SRE (difference, 7.8 [95% CI, 4.2-11.3] months) but not with OS (difference, 1.6 [95% CI, -2.5 to 5.8] months). In the ADT cohort, BMA use was associated with both time to SRE (difference, 9.3 [95% CI, 5.2-13.3] months) and OS (difference, 5.5 [95% CI, 3.2-9.8] months). No evidence was found that the outcomes of BMA varied by AAP or ADT (hazard ratio for time to SRE, 0.99 [95% CI, 0.48-2.08]; P = .99 for interaction; hazard ratio for OS, 1.31 [95% CI, 0.88-1.96]; P = .18 for interaction). Conclusions and Relevance: The findings of this cohort study suggest that use of BMAs was associated with a longer time to SRE in patients with high-risk mCSPC treated with ADT, with or without AAP, suggesting that BMA use might provide benefits to this population.

PRESTO: A Phase III, Open-Label Study of Intensification of Androgen Blockade in Patients With High-Risk Biochemically Relapsed Castration-Sensitive Prostate Cancer (AFT-19).

PURPOSE: Patients with biochemically recurrent prostate cancer (BRPC) after radical prostatectomy and a short PSA doubling time are at risk for distant metastases. Apalutamide, an androgen receptor antagonist, and abiraterone acetate plus prednisone (AAP) prolong survival in the metastatic setting. We evaluated whether intensification of androgen-deprivation therapy (ADT) improves outcomes in BRPC. PATIENTS AND METHODS: PRESTO is a randomized phase III, open-label trial in patients with BRPC and PSA doubling time ≤9 months (ClinicalTrials.gov identifier: NCT03009981). Patients were randomly assigned 1:1:1 to receive a finite 52-week treatment course with ADT control, ADT + apalutamide, or ADT + apalutamide + AAP. The primary end point was PSA progression-free survival (PSA-PFS), defined as serum PSA >0.2 ng/mL after treatment completion. RESULTS: Five hundred three patients were enrolled. The median PSA was 1.8 ng/mL (IQR, 1.0-3.6). At the first planned interim analysis, both experimental arms significantly prolonged PSA-PFS compared with the control arm (median, 24.9 months for ADT + apalutamide v 20.3 months for ADT; hazard ratio [HR], 0.52 [95% CI, 0.35 to 0.77]; P = .00047; median, 26.0 months for ADT + apalutamide + AAP v 20.0 months for ADT; HR, 0.48 [95% CI, 0.32 to 0.71]; P = .00008). Median time to testosterone recovery did not differ across treatment arms. The most common grade ≥3 adverse event was hypertension (7.5%, 7.4%, and 18% in ADT, ADT + apalutamide, and ADT + apalutamide + AAP arms, respectively). CONCLUSION: Intensified AR blockade for a finite duration prolongs PSA-PFS with a manageable safety profile, without adversely affecting time to testosterone recovery. The addition of apalutamide to ADT should be considered in patients with high-risk BRPC.

A territory-wide real-world efficacy and toxicity analysis of abiraterone acetate versus docetaxel in 574 Asian patients with metastatic hormone-sensitive prostate cancer.

INTRODUCTION: Abiraterone acetate (ABI) or docetaxel (DOC), in addition to androgen-deprivation therapy (ADT), are current treatment options for metastatic hormone-sensitive prostate cancer (mHSPC). No randomized head-to-head trial has compared these 2 mHSPC treatments, and real-world data regarding their outcomes in Asian patients are lacking. PATIENTS AND METHODS: The medical records of mHSPC patients who began upfront ABI or DOC treatment in addition to ADT at seven public oncology centers in Hong Kong between 2015 and 2021 were reviewed. The primary endpoint was progression-free survival (PFS). Secondary endpoints included overall survival (OS), prostate-specific antigen (PSA) response, and toxicities. Kaplan-Meier and multivariate Cox regression analyses were performed. RESULTS: A total of 574 patients were included, of whom 419 received DOC and 155 received ABI. The median follow-up duration was 22.4 (DOC group: 23.8; ABI group: 17.3) months. The ABI group demonstrated significantly better PFS than the DOC group (not reached vs. 15.1 months: hazard ratio = 0.37; 95% confidence interval = 0.28-0.50; P < .001). No significant OS difference was observed (P = .58). Failure to achieve a ≥ 90% decline in PSA level at 3 months and failure to achieve an undetectable PSA nadir were each associated with unfavorable PFS and OS. Patients who received DOC had a higher rate of febrile neutropenia, whereas those who received ABI had higher rates of grade ≥ 3 hypokalemia and elevated alanine transaminase. Treatment discontinuation due to toxicities was more common in the DOC (3.6%) than the ABI (0.6%) group. CONCLUSION: In Asian mHSPC patients, upfront ABI + ADT was associated with better PFS than DOC + ADT, with no significant OS difference. PSA kinetics may help stratify the prognosis for treatment intensification. Toxicity profiles were different, with a higher rate of toxicity-related treatment discontinuation in the DOC group.

Bioequivalence, food effect and comparative pharmacokinetics of SUVN-1105, a novel granule formulation of abiraterone acetate, to Zytiga in healthy male subjects.

PURPOSE: SUVN-1105 is a novel formulation of abiraterone acetate which was developed to demonstrate improved bioavailability, compared to Zytiga and Yonsa, and to reduce the dose and eliminate the food effect. A Phase 1 study was conducted to assess the bioequivalence, food effect, and comparative pharmacokinetics of SUVN-1105 to Zytiga in healthy male subjects. METHODS: The study comprised of 2 segments. Segment 1 was a single-center, 4-period crossover, open-label, fixed treatment sequence, single-dose study to evaluate the safety and pharmacokinetics of SUVN-1105 (N = 12 subjects per period). Segment 2 was a single-center, open-label, single-dose, randomized, 4-period, 4-treatment, 4-sequence crossover study to evaluate bioequivalence and comparative pharmacokinetics of SUVN-1105 against Zytiga (N = 44) under overnight fasted, modified fasted, and fed conditions. RESULTS: Abiraterone exposures appeared to increase proportionately with SUVN-1105 dose (200 mg vs. 250 mg) in Segment 1. In Segment 2, abiraterone exposures of 250 mg SUVN-1105 in the fasted or fed conditions were higher than those of Zytiga 1000 mg in the overnight fasted conditions. Abiraterone exposures of 250 mg SUVN-1105 decreased in the fed conditions (64% and 29% decrease in Cmax and AUC, respectively) compared to overnight fasted conditions. CONCLUSIONS: The abiraterone exposures of 250 mg SUVN-1105 in the fasted or fed conditions fall within the abiraterone exposures of 1000 mg Zytiga in fasted and modified fasted conditions. Single doses of SUVN-1105 were safe and well-tolerated in healthy males both in the fasted and fed conditions.

Neoadjuvant Cabazitaxel plus Abiraterone/Leuprolide Acetate in Patients with High-Risk Prostate Cancer: ACDC-RP Phase II Trial.

PURPOSE: Early treatment intensification with neoadjuvant therapy may improve outcomes in patients with high-risk, localized prostate cancer treated with radical prostatectomy. Our objective was to compare pathologic, oncologic, and safety outcomes of neoadjuvant abiraterone acetate plus leuprolide acetate with or without cabazitaxel prior to radical prostatectomy in patients with localized, high-risk prostate cancer. PATIENTS AND METHODS: This open-label, multicenter, phase II trial randomized men with clinically localized, D'Amico high-risk prostate cancer to neoadjuvant abiraterone acetate (1,000 mg/day) and leuprolide acetate (22.5 mg every 3 months) with or without cabazitaxel (25 mg/m2) prior to radical prostatectomy. The primary outcome was pathologic complete response (pCR) or minimal residual disease (MRD). Secondary outcomes included surgical margins, lymph node involvement, pathologic stage, 12-month biochemical relapse-free survival (BRFS) rates, and safety profile. RESULTS: The per-protocol population consisted of 70 patients [cabazitaxel arm (Arm A): 37, no cabazitaxel arm (Arm B): 33]. Median patient age and prostate-specific antigen levels were 63.5 years [interquartile range (IQR), 58.0-68.0] and 21.9 ng/mL (IQR, 14.6-42.8), respectively. pCR/MRD occurred in 16 (43.2%) versus 15 patients (45.5%) in arms A and B, respectively (P = 0.85). pCR occurred in two (5.4%) versus three patients (9.1%) in arms A and B, respectively (P = 0.66). Patients with ≤ 25% total biopsy cores positive had increased odds of pCR/MRD (P = 0.04). Patients with pCR/MRD had superior 12-month BRFS rates (96.0% vs. 62.0%, P = 0.03). Grade 3+ adverse events occurred in 42.5% and 23.7% of patients in arms A and B, respectively (P = 0.078). CONCLUSIONS: Neoadjuvant cabazitaxel addition to abiraterone acetate/leuprolide acetate prior to radical prostatectomy did not improve pCR/MRD in clinically localized, high-risk prostate cancer.

Adherence to hormone therapy in patients with mCRPC: psychometric validation of the A-HT questionnaire.

Abstract: The incidence rate of prostate cancer (PCa) in many Western countries is high, contributing greatly to the cancer disease bur-den. In most cases, patients progress to metastatic disease defined as castration-resistant prostate cancer after androgen deprivation (mCRPC) following primary treatment where the majority of patients receive first-line new-generation oral hormonal therapies (HT) such as Abiraterone Acetate (AA) and Enzalutamide (ENZ). Despite the importance of correct intake of these drugs, adherence in patients with mCRPC is still poorly investigated and managed with measures not specific to this population. A self-report questionnaire was developed and validated with women with breast cancer treated with oral HT (A-BET). Therefore, this study aims to test the psychometric properties of this instrument on patients with mCRPC treated with AA or ENZ. A prospective observational validation study. The questionnaire was completed by all participants and again after 7/10 days by a randomized subsample to assess stability. Sixty-six patients completed the study (mean age of 72.8 years) and 31 completed the re-test (mean age of 72.7 years). Content validity reported excellent results. Cronbach's alpha of each item showed a strong correlation. Validation of an instrument to measure adherence to HT in patients with mCRPC can be a valuable tool for health professionals involved in patient care. In addition, having a population-specific validated instrument allows to make comparisons between results from different observations.

Abiraterone acetate and prednisone in metastatic castration-resistant prostate cancer: a real-world retrospective study in China.

Background: This research work was aimed at evaluating the incidence and risk factors of adverse events (AEs) occurring in patients treated with abiraterone acetate (AA) and prednisone (PDN) outside clinical trials. These associations were assessed regarding the survival outcomes. Methods: The study included 191 patients aged ≥18 years of confirmed metastatic castration-resistant prostate cancer (mCRPC) between March 2017 and April 2022. AE incidences were descriptively summarized from the whole cohort. Baseline characteristics, safety (treatment-emergent AEs and severe AEs), and efficacy [progression-free survival (PFS)] were analyzed. Multi-variable Cox proportional hazards models were employed to assess the factors linked with PFS. Results: Overall, the median PFS was 17.16 months (range, 0.5-57.58). Patient baseline prostate-specific antigen (PSA) ≧̸10 ng/ml (p = 0.000), multiple organ metastasis (p = 0.007), hypertension (p = 0.004), and coronary heart disease (p = 0.004) were associated with worse PFS; however, radiotherapy (p = 0.028) was linked to better PFS at univariate analysis in the overall cohort. Baseline multiple organ metastasis, hypertension, and radiotherapy remained statistically significant in multivariable models (p = 0.007, p= 0.005, and p = 0.011, respectively).Incidence of AEs showed increased bilirubin (BIL) (55/191 patients, 28.8%) followed by increased alanine aminotransferase/aspartate aminotransferase (ALT/AST) (48/191 patients, 25.09%). The most common grade 3 AEs were increased ALT (3/191, 1.57%) followed by elevated BIL, hypercholesterolemia, and hypokalemia. Anemia had shorter PFS. There were no unexpected AEs in any patient. Conclusion: AA is effective and tolerated in asymptomatic or slightly symptomatic mCRPC in "real-life" setting. The survival outcomes are influenced by multiple organ metastasis, hypertension, and radiotherapy.

Association between RCT methodology and disease indication with mineralocorticoid-related toxicity for patients receiving abiraterone acetate for advanced prostate cancer: A meta-analysis of RCTs.

INTRODUCTION: While abiraterone acetate (AA) has demonstrated survival benefit in advanced prostate cancer (APC), meaningful cardiotoxicity is observed. It is unclear whether the magnitude differs based on disease indication and concurrent steroid administration. METHODS: We performed a systematic review and meta-analysis of phase II/III RCTs of AA in APC published as of August 11, 2020. Primary outcomes examined were all- and high-grade (grade ≥ 3) hypokalemia and fluid retention, and secondary outcomes included hypertension and cardiac events. We performed random effects meta-analysis comparing intervention (AA + steroid) and control (placebo ± steroid), stratified by treatment indication and whether patients received steroids. RESULTS: Among 2,739 abstracts, we included 6 relevant studies encompassing 5901 patients. Hypokalemia and fluid retention were observed more frequently among patients receiving AA (odds ratio [OR] 3.10 [95% CI 1.69-5.67] and 1.41 [95% CI 1.19-1.66]). This was modified by whether patients in the control received steroids: trials where control patients did not demonstrated a larger association between AA and hypokalemia (OR 6.88 [95% CI 1.48-2.36] versus OR 1.86 [95% CI 4.97-9.54], P < .0001) and hypertension (OR 2.53 [95% CI 1.91-3.36] vs. OR 1.55 [95% CI 1.17-2.04], P = .1) than those where steroids were administered. We observed heterogeneity due to indication: there were greater effects on hypokalemia (P < 0001), hypertension (P = .03), and cardiac disorders (P = .01) among patients treated for mHSPC than mCRPC. CONCLUSIONS: The magnitude of cardiotoxicity with AA differs based on trial design and disease indication. These data are valuable in treatment decisions and highlight utilization of appropriate data for counseling.

Adverse Events of Abiraterone Acetate vs Enzalutamide.

INTRODUCTION: This study aimed to highlight the comprehensive differences in adverse events between abiraterone and enzalutamide based on a big data data set. METHODS: We downloaded adverse event data sets of abiraterone and enzalutamide from the Food and Drug Administration Adverse Event Reporting System database. We used the Medical Dictionary for Regulatory Activities to treat each adverse event as a preferred term and grouped it into the System Organ Class. Logistic regression analyses were performed to compare abiraterone and enzalutamide. RESULTS: In total, we extracted 59,680 data sets. After exclusion by criteria, we included 26,015 reports on enzalutamide and 7,507 on abiraterone. Enzalutamide and abiraterone presented different toxicity profiles in most System Organ Classes. Overall, the reporting odds ratio indicated a higher incidence rate of serious adverse events for abiraterone than enzalutamide. CONCLUSIONS: In conclusion, our findings suggest that both drugs present a discrete and nonoverlapping toxicity profile that varies by System Organ Class and patient age. This data set confirms, for the most part, what has been reported in clinical trials as well as true real-world reports.

Prostate-specific antigen response after Abiraterone treatment in mCRPC: PSA as a predictor of overall survival.

OBJECTIVES: Abiraterone Acetate (AA) is an important agent in the treatment of advanced prostate cancer. It was primarily approved for the treatment of metastatic castration-resistant prostate cancer (mCRPC) after failure of androgen deprivation therapy. There is still no available strong data regarding the impact of early decline of prostate-specific antigen (PSA) in the overall survival. The aim of this study was to evaluate the clinical efficacy of an early prostate-specific antigen response as a predictor of overall survival (OS) in metastatic castration-resistant prostate cancer when treated with Abiraterone Acetate. MATERIALS AND METHODS: A dual center, retrospective, cohort study on patients diagnosed with mCRPC treated with abiraterone between 2013 and 2020 was performed. Primary end-point was to demonstrate the efficacy of AA, with the analysis of PSA decline, and the correlation with overall survival. RESULTS: The cohort analysis consisted of 84 patients with a median age of 71 ± 9 years. A PSA response of > 30% and > 50% at 60 and 90 days was associated with improved OS. Multivariate analysis revealed that a 60 day PSA decline of > 30% was predictive of overall survival. Median OS of diag-nosed mCRPC patients was 28 months. Docetaxel pre-treatment was not associated with longer OS. The median duration of drug exposure for patients submitted to AA was found to be 14 months. CONCLUSIONS: Early PSA response rate can offer clinically meaningful information and can be considered a surrogate of longer OS. A > 30% or > 50% prostate-specific antigen decline at 60 and 90 days provided an important low-cost clinical tool to predict subsequent events in mCRPC patients treated with abiraterone.

Randomized Phase III Study of Enzalutamide Compared With Enzalutamide Plus Abiraterone for Metastatic Castration-Resistant Prostate Cancer (Alliance A031201 Trial).

PURPOSE: Enzalutamide and abiraterone both target androgen receptor signaling but via different mechanisms. The mechanism of action of one drug may counteract the resistance pathways of the other. We sought to determine whether the addition of abiraterone acetate and prednisone (AAP) to enzalutamide prolongs overall survival (OS) in patients with metastatic castration-resistant prostate cancer (mCRPC) in the first-line setting. PATIENTS AND METHODS: Men with untreated mCRPC were randomly assigned (1:1) to receive first-line enzalutamide with or without AAP. The primary end point was OS. Toxicity, prostate-specific antigen declines, pharmacokinetics, and radiographic progression-free survival (rPFS) were also examined. Data were analyzed using an intent-to-treat approach. The Kaplan-Meier estimate and the stratified log-rank statistic were used to compare OS between treatments. RESULTS: In total, 1,311 patients were randomly assigned: 657 to enzalutamide and 654 to enzalutamide plus AAP. OS was not statistically different between the two arms (median, 32.7 [95% CI, 30.5 to 35.4] months for enzalutamide v 34.2 [95% CI, 31.4 to 37.3] months for enzalutamide and AAP; hazard ratio [HR], 0.89; one-sided P = .03; boundary nominal significance level = .02). rPFS was longer in the combination arm (median rPFS, 21.3 [95% CI, 19.4 to 22.9] months for enzalutamide v 24.3 [95% CI, 22.3 to 26.7] months for enzalutamide and AAP; HR, 0.86; two-sided P = .02). However, pharmacokinetic clearance of abiraterone was 2.2- to 2.9-fold higher when administered with enzalutamide, compared with clearance values for abiraterone alone. CONCLUSION: The addition of AAP to enzalutamide for first-line treatment of mCRPC was not associated with a statistically significant benefit in OS. Drug-drug interactions between the two agents resulting in increased abiraterone clearance may partly account for this result, although these interactions did not prevent the combination regimen from having more nonhematologic toxicity.

Niraparib and Abiraterone Acetate for Metastatic Castration-Resistant Prostate Cancer.

PURPOSE: Metastatic castration-resistant prostate cancer (mCRPC) remains a lethal disease with current standard-of-care therapies. Homologous recombination repair (HRR) gene alterations, including BRCA1/2 alterations, can sensitize cancer cells to poly (ADP-ribose) polymerase inhibition, which may improve outcomes in treatment-naïve mCRPC when combined with androgen receptor signaling inhibition. METHODS: MAGNITUDE (ClinicalTrials.gov identifier: NCT03748641) is a phase III, randomized, double-blinded study that evaluates niraparib and abiraterone acetate plus prednisone (niraparib + AAP) in patients with (HRR+, n = 423) or without (HRR-, n = 247) HRR-associated gene alterations, as prospectively determined by tissue/plasma-based assays. Patients were assigned 1:1 to receive niraparib + AAP or placebo + AAP. The primary end point, radiographic progression-free survival (rPFS) assessed by central review, was evaluated first in the BRCA1/2 subgroup and then in the full HRR+ cohort, with secondary end points analyzed for the full HRR+ cohort if rPFS was statistically significant. A futility analysis was preplanned in the HRR- cohort. RESULTS: Median rPFS in the BRCA1/2 subgroup was significantly longer in the niraparib + AAP group compared with the placebo + AAP group (16.6 v 10.9 months; hazard ratio [HR], 0.53; 95% CI, 0.36 to 0.79; P = .001). In the overall HRR+ cohort, rPFS was significantly longer in the niraparib + AAP group compared with the placebo + AAP group (16.5 v 13.7 months; HR, 0.73; 95% CI, 0.56 to 0.96; P = .022). These findings were supported by improvement in the secondary end points of time to symptomatic progression and time to initiation of cytotoxic chemotherapy. In the HRR- cohort, futility was declared per the prespecified criteria. Treatment with niraparib + AAP was tolerable, with anemia and hypertension as the most reported grade ≥ 3 adverse events. CONCLUSION: Combination treatment with niraparib + AAP significantly lengthened rPFS in patients with HRR+ mCRPC compared with standard-of-care AAP.[Media: see text].

Niraparib with Abiraterone Acetate and Prednisone for Metastatic Castration-Resistant Prostate Cancer: Phase II QUEST Study Results.

Niraparib (NIRA) is a highly selective inhibitor of poly (adenosine diphosphate-ribose) polymerase, PARP1 and PARP2, which play a role in DNA repair. The phase II QUEST study evaluated NIRA combinations in patients with metastatic castration-resistant prostate cancer who were positive for homologous recombination repair gene alterations and had progressed on 1 prior line of novel androgen receptor-targeted therapy. Results from the combination of NIRA with abiraterone acetate plus prednisone, which disrupts androgen axis signaling through inhibition of CYP17, showed promising efficacy and a manageable safety profile in this patient population.

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.

Ascending Flaccid Paralysis Secondary to Hypokalemia in A Cancer Patient using Abiraterone - A Case Report.

BACKGROUND: Prostate cancer (PC) is the most common type of neoplasm in men and the fourth leading cause of mortality in Brazil. The prostate cancer refractory metastatic castration can be treated with abiraterone acetate (AA). CASE PRESENTATION: Its use has been associated with increased survival. However, there are also side effects associated with the use of this drug, such as severe electrolyte disturbances. CONCLUSION: The objective is to report the clinical case of a patient with castration-resistant metastatic prostate cancer who developed ascending flaccid paralysis secondary to severe hypokalemia, probably due to hyperaldosteronism secondary to the use of Abiraterone Acetate, despite the use of Prednisone.

Impact of trough abiraterone level on adverse events in patients with prostate cancer treated with abiraterone acetate.

PURPOSE: We assessed the impact of plasma trough concentrations of abiraterone (ABI) and its metabolite Δ4-abiraterone (D4A) and related polymorphisms on adverse events (AEs) in patients with metastatic prostate cancer who received abiraterone acetate (AA). METHODS: This prospective study enrolled patients with advanced prostate cancer treated with AA between 2016 and 2021. Plasma trough concentrations of ABI and D4A were measured using high-performance liquid chromatography. The impact of HSD3B1 rs1047303, SRD5A2 rs523349, and cytochrome P450 family 3A member 4 rs2242480 polymorphisms on plasma concentrations of ABI and D4A and the incidence of AEs were also assessed. RESULTS: In 68 patients treated with AA, the median ABI and D4A concentrations were 18.1 and 0.94 ng/mL, respectively. The high plasma trough concentration of ABI (≥ 20.6 ng/mL) was significantly associated with the presence of any AE and its independent risk factor based on multivariable analysis (odds ratio, 7.20; 95% confidence interval (CI): 2.20-23.49). Additionally, a high plasma trough concentration of ABI was an independent risk factor of time to withdraw AA (hazard ratio, 4.89; 95% CI: 1.66-14.38). The risk alleles of three polymorphisms were not statistically associated with the ABI and D4A concentrations and the incidence of AEs. CONCLUSIONS: The plasma trough concentration of ABI is associated with the presence of AEs and treatment failure after AA administration. ABI concentration monitoring may be useful in patients with prostate cancer who received AA.

Molecular Profile Changes in Patients with Castrate-Resistant Prostate Cancer Pre- and Post-Abiraterone/Prednisone Treatment.

We identified resistance mechanisms to abiraterone acetate/prednisone (AA/P) in patients with metastatic castration-resistant prostate cancer (mCRPC) in the Prostate Cancer Medically Optimized Genome-Enhanced Therapy (PROMOTE) study.We analyzed whole-exome sequencing (WES) and RNA-sequencing data from 83 patients with metastatic biopsies before (V1) and after 12 weeks of AA/P treatment (V2). Resistance was determined by time to treatment change (TTTC).At V2, 18 and 11 of 58 patients had either short-term (median 3.6 months; range 1.4-4.5) or long-term (median 29 months; range 23.5-41.7) responses, respectively. Nonresponders had low expression of TGFBR3 and increased activation of the Wnt pathway, cell cycle, upregulation of AR variants, both pre- and posttreatment, with further deletion of AR inhibitor CDK11B posttreatment. Deletion of androgen processing genes, HSD17B11, CYP19A1 were observed in nonresponders posttreatment. Genes involved in cell cycle, DNA repair, Wnt-signaling, and Aurora kinase pathways were differentially expressed between the responder and non-responder at V2. Activation of Wnt signaling in nonresponder and deactivation of MYC or its target genes in responders was detected via SCN loss, somatic mutations, and transcriptomics. Upregulation of genes in the AURKA pathway are consistent with the activation of MYC regulated genes in nonresponders. Several genes in the AKT1 axis had increased mutation rate in nonresponders. We also found evidence of resistance via PDCD1 overexpression in responders. IMPLICATIONS: Finally, we identified candidates drugs to reverse AA/P resistance: topoisomerase inhibitors and drugs targeting the cell cycle via the MYC/AURKA/AURKB/TOP2A and/or PI3K_AKT_MTOR pathways.