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Background: This retrospective observational study explored the therapeutic potential of combined androgen blockade (CAB) with bicalutamide (Bic-CAB) as an initial treatment for metastatic hormone-sensitive prostate cancer (mHSPC) in Japan., Methods: The electronic health records of 159 patients with mHSPC from three Japanese institutions who received initial treatment with Bic-CAB between 2007 and 2017 were analyzed. The time to prostate-specific antigen (PSA) progression, duration of Bic-CAB treatment, and overall survival (OS), with various definitions for PSA progression, were assessed. A multivariate Cox proportional hazards model was constructed using clinical parameters to predict time to the end of Bic-CAB treatment and OS., Results: The median observation period was 46.4 months, and the median age of patients at diagnosis was 71 years. A total of 46.5% patients experienced PSA progression with a median survival duration of 29 months (according to Prostate Cancer Clinical Trials Working Group 3 criteria), and 49.1% patients achieved a PSA nadir < 0.2 ng/mL in a median time of 4.7 months. When stratified by PSA nadir and PSA change, patients at low risk for disease progression with a small PSA change due to low initial PSA had a 5-year OS of 100% and a 10-year OS of 75%. The OS during the observation period was 72.9 months., Conclusion: These findings highlight the potential effect of Bic-CAB in patients with mHSPC who were at low risk for disease progression. Initial treatment with Bic-CAB and adjusting treatment early based on PSA dynamics may be a reasonable treatment plan for these patients., (© 2024. The Author(s).)

Objective: The objective of this study was to compare the prognostic outcomes between metastatic castration-sensitive prostate cancer (mCSPC) patients receiving conventional androgen deprivation therapy (ADT) and those receiving ADT plus a novel androgen-receptor signaling inhibitor (ARSI) in routine clinical practice in Japan., Methods: This was conducted as a retrospective multicenter study including 581 mCSPC patients, consisting of 305 receiving ADT alone or in combination with bicalutamide (group 1) and 276 receiving ADT plus one of the following ARSIs: abiraterone acetate, apalutamide, or enzalutamide (group 2). Prognostic outcomes between these 2 groups were comprehensively compared., Results: In the entire cohort, prostate-specific antigen-progression-free survival (PSA-PFS) in group 2 was significantly longer than that in group 1, while no significant difference was noted in overall survival (OS) between the two groups. In patients corresponding to the LATITUDE high-risk group, however, both PSA-PFS and OS in group 2 were significantly longer than those in group 1. Of several factors examined, the following were identified as independent predictors of poor PSA-PFS in the entire cohort as well as the LATITUDE high-risk group: high C-reactive protein, high lactate dehydrogenase, high alkaline phosphatase, high Gleason score, and group 1. Furthermore, it was possible to precisely classify both the entire cohort and LATITUDE high-risk group into 3 risk groups regarding PSA-PFS according to the positive numbers of independent factors: positive for ≤1 factor, favorable; 2 factors, intermediate; and ≥3 factors, poor., Conclusion: Combined use of ARSIs with ADT could improve the prognostic outcomes of mCSPC patients, particularly those in the LATITUDE high-risk group, in real-world clinical practice in Japan., (© 2024 The Japanese Urological Association.)

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., (© 2021 Wiley Periodicals LLC.)

Background: Recent landmark randomized trials (CHAARTED and LATITUDE studies) have highlighted potent upfront therapy for "high-volume" and "high-risk" metastatic castration-naïve prostate cancer (mCNPC). However, treatment response shows racial differences. We aimed to propose a novel definition for "high-volume" prostate cancer in Asians., Methods: We retrospectively pursued 426 patients with de novo mCNPC from multiple institutions between 1999 and 2017. All patients received androgen deprivation therapy alone as initial treatment. We evaluated the number of bone metastases at diagnosis to clarify the clinical significance for progression-free survival and overall survival (OS). Statistical analyses were conducted using the Mann-Whitney U test, Cox proportional hazard models, and Kaplan-Meier methods., Results: Median age and prostate-specific antigen level were 73 years and 266.2 ng/ml, respectively. Median OS was 55.5 months in patients who met the CHAARTED high criteria (vs 33.1 months in the trial). We evaluated 5 thresholds in the number of bone metastases (≥4, ≥6, ≥11, ≥16, and ≥21) to investigate the prognostic values. Patients with ≥11 bone metastases showed the highest HR for OS (2.766). Patients with 11 to 20 bone metastases had a significantly shorter OS than those with ≤10 metastases (P = .0001). We, therefore, proposed modified CHAARTED and LATITUDE high criteria (extending bone metastases ≥11). In multivariate analysis, the modified criteria were the only independent prognostic factors for OS (P = .0272 and P = .042, respectively). Conversely, no significant differences in OS were seen between patients with 1 to 3 bone metastases and 4 to 10 (P = .7513)., Conclusion: Our exploratory study suggested ≥11 bone metastases as a suitable definition for "high-volume" prostate cancer in Asians. A larger, prospective study is warranted to verify our findings., (© 2020 Wiley Periodicals, Inc.)

Introduction and Aim: We assessed the characteristics of virological response to a combination treatment of ombitasvir, paritaprevir, and ritonavir in hepatitis C virus genotype 1-infected elderly Japanese patients., Material and Methods: This multicenter prospective study was conducted at six locations in Japan. Seventy patients with chronic hepatitis C virus genotype 1b infection were orally administered ombitasvir/paritaprevir/ritonavir once daily for 12 weeks. The primary endpoint was the proportion of elderly patients with sustained virological response (SVR) 12 weeks after the completion of treatment. Adverse events were also recorded to evaluate drug safety and tolerability during the trial period. SVR in elderly patients (age > 65; 94% [47 / 50]) was lower than that in younger patients (100% [20 / 20])., Results: No significant differences in SVR 12 weeks after the completion of treatment were observed between the age groups (P = 0.153). Adverse events were observed in 16 patients (23.3%). Multivariate analysis confirmed that the change or discontinuation of concomitant drugs owing to drug interactions was independent of risk factors for adverse events associated with this drug combination (P = 0.015; odds ratio, 15.9; 95% confidence interval, 1.79 - 148). Ombitasvir/paritaprevir/ritonavir combination treatment was highly effective in elderly patients., Conclusion: Tolerability should be monitored in older patients for whom concomitant medications are discontinued or changed because of drug interactions., (Copyright © 2019 Fundación Clínica Médica Sur, A.C. Published by Elsevier España, S.L.U. All rights reserved.)

Treatment of HCV genotype (GT) 2-infected Japanese patients with paritaprevir (NS3/4A inhibitor boosted with ritonavir) and ombitasvir (NS5A inhibitor) without ribavirin for 12 weeks in the phase 2 study M12-536, and with ribavirin for 16 weeks in phase 3 study GIFT II resulted in SVR rates of 72.2% to 91.5%. Overall, 11 out of 125 patients with GT2a and 37 out of 79 patients with GT2b infection experienced virologic failure. The prevalence of baseline polymorphisms in NS3 and NS5A and their the impact on treatment outcome, as well as the development of viral resistance in GT2-infected patients experiencing virologic failure were evaluated by HCV NS3 and NS5A population and clonal sequence analyses. Baseline polymorphisms in NS3 that confer resistance to paritaprevir were rare in both GT2a- and GT2b-infected patients, while baseline polymorphisms in NS5A that confer resistance to ombitasvir were detected in 11.2% and 14.1% of the GT2a- and GT2b-infected patients, respectively. There was no significant impact of baseline polymorphisms on treatment outcome in Japanese patients. The most common treatment-emergent substitutions at the time of virologic failure occurred at amino acid positions 168 in NS3 and 28 in NS5A in both GT2a- and GT2b-infected patients. Although there was a higher rate of virologic failure in patients with GT2b infection, the resistance analyses presented in this report support the conclusion that testing for baseline resistance-associated polymorphisms is not warranted for HCV GT2-infected patients treated with a regimen of ombitasvir/paritaprevir/ritonavir + ribavirin for 16 weeks., (© 2017 The Authors. Journal of Medical Virology Published by Wiley Periodicals, Inc.)

Introduction: In Japan, hepatitis C virus (HCV) genotype (GT) 2 accounts for approximately 32% of HCV infections. Limited treatment options exist in Japan for HCV GT2-infected patients. GIFT-II was a phase 3, randomized, open-label study evaluating the efficacy and safety of 16- and 12-week regimens of co-formulated ombitasvir (OBV)/paritaprevir (PTV)/ritonavir (r) plus ribavirin (RBV) in Japanese adults with HCV GT2 infection., Methods: Patients were randomized in a 1:1 ratio to once-daily, co-formulated OBV/PTV/r (25/150/100 mg) with weight-based RBV for 16 or 12 weeks. The primary efficacy endpoint was the sustained virologic response at 12 weeks post-treatment (SVR12) rate in the primary efficacy population of non-cirrhotic treatment-naive patients., Results: A total of 171 patients were randomized to OBV/PTV/r + RBV. In the primary efficacy population, SVR12 rates were 91.5% (43/47; 95% confidence interval 83.5-99.5%) and 75.0% (36/48; 95% confidence interval 62.8-87.2%) in the 16-week arm and 12-week arm, respectively. No patient in the 16-week arm relapsed by post-treatment week 12. Among non-cirrhotic treatment-experienced patients, the overall SVR rate in the 16-week arm was 75.8% (25/33) and was highest [93.8% (15/16)] among those who had relapsed after previous interferon-based therapy. SVR12 rates were consistently higher in patients with HCV GT2a infection versus HCV GT2b infection [16-week treatment arm: 93.9% (31/33) versus 85.7% (12/14) and 93.8% (15/16) versus 56.3% (9/16) among non-cirrhotic treatment-naive and treatment-experienced patients, respectively]. No patient discontinued treatment because of an adverse event. The most common adverse events were anemia, increased blood bilirubin, and nasopharyngitis., Conclusions: OBV/PTV/r + RBV for 16 weeks resulted in high SVR12 rates in non-cirrhotic Japanese patients infected with HCV GT2 who were treatment-naive or who had relapsed after an interferon-based therapy. Higher SVR12 rates were observed among patients with HCV GT2a infection versus those with GT2b infection. This regimen demonstrated a favorable safety profile., Trial Registration: ClinicalTrials.gov identifier, NCT02023112., Funding: AbbVie.

Introduction: The all-oral 2 direct-acting antiviral (DAA) regimen of ombitasvir/paritaprevir/ritonavir 25/150/100 mg once a day has been evaluated in hepatitis C virus subgenotype 1b-infected Japanese adults in the GIFT-I study. The aim of this analysis was to evaluate potential relationships between DAA exposures and laboratory abnormalities/adverse events of peripheral edema in patients in GIFT-I., Methods: The GIFT-I study consisted of a randomized, double-blind, placebo-controlled substudy in patients without cirrhosis and an open-label substudy in patients with compensated cirrhosis. Patients received ombitasvir/paritaprevir/ritonavir for 12 weeks. Exposure-response relationships between individual components of the ombitasvir/paritaprevir/ritonavir regimen and clinical parameters of interest were explored using pharmacokinetic and clinical data from patients in the study. Graphical analyses were performed. For events that occurred in at least 10 patients (total bilirubin elevation ≥grade 2 and peripheral edema ≥grade 1), multivariate logistic regression analyses were used to identify significant relationships between predictor variables (drug exposures) and response variables (probability of adverse events or laboratory abnormalities), with consideration for the effect of potential covariates and baseline status of response variables., Results: Data from 321 noncirrhotic and 42 compensated cirrhotic patients were analyzed. There were 14 events of peripheral edema (10 at grade 1 and 4 at grade 2) in patients who received concomitant administration of calcium channel blockers and ombitasvir/paritaprevir/ritonavir. There was no apparent relationship between the incidences of peripheral edema and exposures of paritaprevir, ombitasvir, or ritonavir. There was a shallow relationship between total bilirubin elevation and exposures of paritaprevir which is an inhibitor of bilirubin transporter organic anion-transporting polypeptide 1B. Based on graphical analyses, exposures of paritaprevir, ombitasvir, or ritonavir were weakly associated with hemoglobin decrease, but not associated with post baseline alanine aminotransferase or aspartate aminotransferase elevations., Conclusions: In Japanese patients, there were no associations or only shallow relationships between DAA exposures and peripheral edema or laboratory abnormalities. Consequently, therapeutic drug monitoring is not expected to be beneficial in managing patients on the 2-DAA regimen., Trial Registration: ClinicalTrials.gov identifier, NCT02023099., Funding: AbbVie Inc.

Purpose: The 2 direct-acting antiviral combination (2D) of ombitasvir and paritaprevir (coadministered with ritonavir) is being evaluated for the treatment of chronic hepatitis C virus infection in Japan. Ursodeoxycholic acid (UDCA) and glycyrrhizin (GCR) are hepatoprotective agents widely used in Japan. A drug-drug interaction (DDI) study was conducted to guide dosing recommendations for UDCA and GCR when coadministered with the 2D regimen., Methods: DDIs between the 2D regimen (ombitasvir/paritaprevir/ritonavir 25/150/100 mg orally once daily) and UDCA (50 mg orally 3 times daily) or GCR (80 mg intravenously once daily) were evaluated in a 2-arm, multiple-dose study in 24 Japanese healthy subjects under fed conditions. Pharmacokinetic and safety evaluations were performed when UDCA or GCR and the 2D regimen were administered alone and during coadministration. Exposures from coadministration of the 2D regimen plus UDCA or GCR versus the 2D regimen, UDCA, or GCR alone were compared using repeated-measures analyses of natural logarithms of the maximum plasma concentration (Cmax) and area under the curve (AUC)., Findings: After coadministration of the 2D regimen and UDCA, steady-state exposures (Cmax and AUC) of ombitasvir, paritaprevir, and ritonavir showed a ≤9% change, and UDCA exposures showed a ≤20% change compared with administration alone. When the 2D regimen and GCR were coadministered, steady-state exposures of ombitasvir, paritaprevir, and ritonavir were not affected (≤9% change), GCR AUC increased by 49%, and GCR Cmax was unaffected (<1% change)., Implications: No dose adjustment is needed for UDCA, GCR, or the 2D regimen when UDCA or GCR is coadministered with the 2D regimen in hepatitis C virus-infected patients under fed conditions. Clinical monitoring of patients using GCR is recommended due to an approximately 50% increase in GCR AUC when coadministered with the 2D regimen., (Copyright © 2015 Elsevier HS Journals, Inc. All rights reserved.)

Background: Primary hormonal therapy has been mostly used for patients with advanced prostate cancer, as international guidelines do not recommend its use for patients at earlier disease stages. However, there seems to be a discrepancy between the guideline recommendations and clinical practice on the use of primary androgen deprivation therapy for localized prostate cancer in Japan. Therefore, we retrospectively analyzed a single-institution experience in primary combined androgen blockade (CAB) for localized prostate cancer., Patients and Methods: The study included 187 patients with T1c-T3a prostate cancer unsuitable for local definitive treatment and treated with primary CAB. Clinical outcomes, predictive factors of PSA relapse and adverse events were investigated., Results: The progression-free, disease-specific, and overall survival rates of all patients at 5 years were 63.0, 99.4 and 95.9%, respectively. Of the several parameters isolated as predictors of prostate-specific antigen (PSA) progression, nadir PSA level and the percentage of positive biopsy cores (%PBC) remained as independent prognostic factors on multivariate analysis. Toxicities were mild to moderate and well tolerated., Conclusions: Primary CAB treatment brought initial disease control without relapse in the majority of our selected cases. The %PBC may help predict time to relapse in the pretreatment setting. The results implicate that CAB can be an option as a primary treatment for clinically localized prostate cancer unsuitable for local definitive treatment. To confirm the exact efficacy of primary CAB, these findings should be reviewed in a large cohort of patients with long-term follow-up from various viewpoints, including disease control, toxicities, quality-of-life and medical cost.

Stage C prostate cancer, where the tumour has extended beyond the capsule of the prostate, is typically a high-risk disease. According to the National Cancer Institute Physician Data Query the treatments of choice for stage C disease comprise external beam radiation therapy (with or without the addition of adjuvant hormone therapy), androgen deprivation by either surgery or hormone therapy, radical prostatectomy, or careful observation. From 2001, the Japanese Urological Association initiated computer-based registration of all patients with prostate cancer in Japan. Data show that overall, 57% of all patients and 46% of those with T1c to T3 disease had primary androgen deprivation therapy (PADT). Similarly, the Japanese Prostate Cancer Group undertook a large-scale epidemiological surveillance study in Japan and found that the most commonly used hormone therapy is PADT, regardless of disease stage. To date, two randomized, controlled trials of the effect of PADT on stage C prostate cancer in elderly (> or =75 years old) patients have been undertaken in Japan. The results showed that patients with locally advanced prostate cancer treated with PADT are likely to have a life-expectancy similar to that of the normal population. In one study, combined androgen blockade (CAB) with leuprorelin plus chlormadinone appeared to prolong time to disease progression when compared with leuprorelin monotherapy, but there was no difference in survival between these treatment groups. In a second study CAB with an luteinizing hormone-releasing hormone (LHRH) agonist plus bicalutamide was found to prolong time to progression when compared with LHRH agonist monotherapy, but survival results for these regimens are still awaited.

Objectives: To evaluate bicalutamide (Casodex) 80 mg as a component of maximum androgen blockade (MAB) in Japanese patients with previously untreated advanced prostate cancer., Methods: 205 patients with previously untreated stage C/D prostate cancer were randomized (1:1) to receive once-daily bicalutamide 80 mg or placebo, each combined with a luteinizing hormone-releasing hormone (LHRH) agonist. Primary study variables were the 12 week prostate-specific antigen (PSA) normalization (i.e. PSA level

Patients with prostate cancer generally respond to androgen withdrawal therapy, but progression to androgen-independence is frequently observed later. To examine whether pretreatment serum androgen status could predict disease progression in metastatic prostate cancer, pretreatment serum testosterone, histological grade, extent of bony metastasis, serum prostate-specific antigen (PSA) response to hormone therapy, and prognosis of the 40 patients with untreated metastatic prostate cancer who received endocrine therapy were evaluated. Although there were no differences in age, pretreatment PSA level, extent of bony disease and histological grade between patients with normal testosterone and those with low testosterone, PSA response after endocrine therapy was better in normal testosterone group. There was a significantly longer interval to disease progression in patients with normal testosterone than in those with low testosterone. The patients with metastatic prostate cancer with low serum testosterone were in the high risk group of worse response to endocrine therapy. Additional therapy might be considered in those patients.