Exploring the optimal sequence of abiraterone and enzalutamide in patients with chemotherapy-naïve castration-resistant prostate cancer: The Kyoto-Baltimore collaboration

OBJECTIVES

To evaluate and compare the efficacy of sequential treatment with abiraterone followed by enzalutamide or vice versa for castration-resistant prostate cancer.

METHODS

We retrospectively evaluated data on 198 consecutive chemotherapy-naïve patients who had received both abiraterone and enzalutamide for castration-resistant prostate cancer at Kyoto University Hospital (including satellite hospitals) and at Johns Hopkins Cancer Center. Prostate-specific antigen progression-free survival and overall survival in patients treated with sequential abiraterone-to-enzalutamide versus enzalutamide-to-abiraterone without intervening therapies were compared.

RESULTS

Overall, 113 patients were treated with the abiraterone-to-enzalutamide sequence and 85 with the enzalutamide-to-abiraterone sequence. Median prostate-specific antigen progression-free survival was not significantly different between abiraterone and enzalutamide in the first-line setting (hazard ratio 0.88, 95% confidence interval 0.66-1.19, P = 0.412), but there was an advantage favoring enzalutamide compared with abiraterone in the second-line setting (hazard ratio 0.67, 95% confidence interval 0.49-0.91, P = 0.009). Furthermore, the combined prostate-specific antigen progression-free survival was significantly longer in the abiraterone-to-enzalutamide sequence than in the enzalutamide-to-abiraterone sequence (hazard ratio 0.56, 95% confidence interval 0.41-0.76, P < 0.001). The difference was significant even in multivariate analyses (hazard ratio 0.65, 95% confidence interval 0.42-0.99, P = 0.044). There was no statistical difference in overall survival between the two sequences in univariate (hazard ratio 0.88, 95% confidence interval 0.53-1.43, P = 0.599) and multivariate analyses (hazard ratio 0.81, 95% confidence interval 0.49-1.35, P = 0.427).

CONCLUSIONS

The abiraterone-to-enzalutamide sequence might have more favorable efficacy in terms of combined prostate-specific antigen progression-free survival than the enzalutamide-to-abiraterone sequence, although no differences in overall survival were observed. This could possibly be attributable to longer prostate-specific antigen progression-free survival with second-line enzalutamide compared with abiraterone.

Exploring optimal sequence of abiraterone and enzalutamide in patients with castration-resistant prostate cancer: The Kyoto-Baltimore collaboration

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Background: Abiraterone (ABI) and enzalutamide (ENZA) are novel hormonal treatments for castration-resistant prostate cancer (CRPC) used before and after docetaxel (DTX) chemotherapy. We aimed to evaluate and compare the efficacy of sequential treatment with ABI followed by ENZA or vice versa in patients with CRPC, using combined data from two institutions. Methods: We retrospectively evaluated data on 352 consecutive patients who had received both ABI and ENZA for CRPC at Kyoto University Hospital and at Johns Hopkins Sidney Kimmel Comprehensive Cancer Center. Using Kaplan-Meier analysis and log-rank tests, we compared PSA progression-free survival (PSA-PFS) and overall survival (OS) in patients treated with sequential ABI-to-ENZA versus ENZA-to-ABI without intervening therapies. Results: The number of patients receiving ABI-to-ENZA and ENZA-to-ABI were 163 (pre-DTX: 116, post-DTX: 47) and 189 (pre-DTX: 85, post-DTX: 104), respectively. The > 50% PSA response rates to ABI and ENZA were 47% and 52% in the first-line CRPC setting, and were 9% and 29% in the second-line setting. In the pre-DTX population, median PSA-PFS was not significantly different between ABI (median: 194 days) and ENZA (median: 126 days) in the first-line setting (p = 0.411), but there was an advantage favoring ENZA (median: 91 days) compared to ABI (median: 55 days) in the second-line setting (p = 0.008). Furthermore, the combined PSA-PFS was significantly longer in the ABI-to-ENZA sequence (median: 455 days) than in the ENZA-to-ABI sequence (median: 296 days) (p < 0.001). There was no statistical difference in OS between the two sequences (p = 0.598). Conclusions: The ABI-to-ENZA sequence may have more favorable efficacy in terms of combined PSA-PFS than the ENZA-to-ABI sequence, although no differences in OS were observed. This may possibly be attributable to higher PSA response rates and longer PSA-PFS to second-line ENZA compared to ABI (i.e., ENZA retains activity after ABI but not vice versa).

Clinical Experience of Late Conversion From Antimetabolites With Standard Exposure Calcineurin Inhibitors to Everolimus With Calcineurin Inhibitor Minimization in Stable Kidney Transplant Recipients With Good Renal Function

INTRODUCTION

This study describes our clinical experience of late conversion from antimetabolites with standard exposure calcineurin inhibitors (CNIs) to everolimus with CNI minimization in stable kidney transplant recipients with good graft function.

PATIENTS AND METHODS

A 1-year retrospective pilot study of 26 kidney recipients converted from antimetabolites with standard exposure CNIs to everolimus with CNI minimization was performed. The recipients enrolled in this study had normal or slightly impaired renal function defined as a serum creatinine value <2.0 mg/dL, and normal or slightly increased albuminuria defined as a urinary albumin excretion rate <100 mg/g creatinine.

RESULTS

The median time from transplant to conversion was 39.5 months posttransplant (range, 3-275). Treatment with everolimus was stopped owing to adverse events in 11 patients (42.3%). In the analysis of the patients in whom everolimus was maintained, the mean estimated glomerular filtration rate (eGFR) significantly increased from 50.7 ± 11.9 mL/min/1.73 m(2) at baseline to 53.6 ± 13.9 mL/min/1.73 m(2) at 1 year after conversion. In the patients in whom everolimus was stopped during the observation period, there was no difference in eGFR between baseline and 1 year after conversion.

CONCLUSIONS

This study demonstrated that, among the patients converted to everolimus at a late stage, there was no deterioration in renal function whether everolimus was maintained or stopped within 1 year after conversion.

Guideline Adherence of Immediate Post-Transurethral Resection Intravesical Chemotherapy for Patients with Nonmuscle Invasive Bladder Cancer

INTRODUCTION

Immediate postoperative instillation of chemotherapy to prevent intravesical recurrence of nonmuscle invasive bladder cancer is supported by level 1 evidence and recommended by contemporary guidelines. However, there have been a few reports on the feasibility and adherence of immediate postoperative chemotherapy instillation after transurethral resection. We retrospectively assessed the adherence rate of this treatment in patients with nonmuscle invasive bladder cancer.

METHODS

We identified 438 patients with clinically Ta/T1 bladder cancer who underwent transurethral resection with curative intent between 2008 and 2013. We investigated the implementation of immediate postoperative instillation of chemotherapy. For those who did not receive this treatment we tried to identify the reasons for nonadministration from the clinical record and categorized them into technical, patient or other factors. We further interrogated clinicopathological characteristics associated with nonadministration.

RESULTS

Overall 193 of the 438 study patients (44.1%) did not receive immediate postoperative instillation of chemotherapy. The noninstillation rate constantly decreased with time from 58.8% to 28.0% during the study period. Deep resection was the most common reason for nonadministration. There was a statistically significant decreasing time trend for nonadministration. Multivariate analysis revealed that clinical stage T1 tumor, negative cytology and larger tumor size were independently associated with nonadministration.

CONCLUSIONS

Guideline adherence improved with time, suggesting that better education and better understanding of the guideline contributed to achieve high adherence. Deep resection was the most common reason for nonadministration, which was associated with clinically infiltrating cancer and larger tumor size.

CCL2 as a potential therapeutic target for clear cell renal cell carcinoma

We previously reported that the pVHL‐atypical PKC‐JunB pathway contributed to promotion of cell invasiveness and angiogenesis in clear cell renal cell carcinoma (ccRCC), and we detected chemokine (C‐C motif) ligand‐2 (CCL2) as one of downstream effectors of JunB. CCL2 plays a critical role in tumorigenesis in other types of cancer, but its role in ccRCC remains unclear. In this study, we investigated the roles and therapeutic potential of CCL2 in ccRCC. Immunohistochemical analysis of CCL2 expression for ccRCC specimens showed that upregulation of CCL2 expression correlated with clinical stage, overall survival, and macrophage infiltration. For functional analysis of CCL2 in ccRCC cells, we generated subclones of WT8 cells that overexpressed CCL2 and subclones 786‐O cells in which CCL2 expression was knocked down. Although CCL2 expression did not affect cell proliferation in vitro, CCL2 overexpression enhanced and CCL2 knockdown suppressed tumor growth, angiogenesis, and macrophage infiltration in vivo. We then depleted macrophages from tumor xenografts by administration of clodronate liposomes to confirm the role of macrophages in ccRCC. Depletion of macrophages suppressed tumor growth and angiogenesis. To examine the effect of inhibiting CCL2 activity in ccRCC, we administered CCL2 neutralizing antibody to primary RCC xenografts established from patient surgical specimens. Inhibition of CCL2 activity resulted in significant suppression of tumor growth, angiogenesis, and macrophage infiltration. These results suggest that CCL2 is involved in angiogenesis and macrophage infiltration in ccRCC, and that CCL2 could be a potential therapeutic target for ccRCC.

Factors predicting efficacy and adverse effects of enzalutamide in Japanese patients with castration-resistant prostate cancer: results of retrospective multi-institutional study

BACKGROUND

We aimed to evaluate the factors predicting efficacy and adverse effects of enzalutamide in patients with castration-resistant prostate cancer.

METHODS

We retrospectively evaluated data on 345 patients who had received enzalutamide for castration-resistant prostate cancer in 20 hospitals (Kyoto University Hospital and other satellite hospitals). Cox proportional hazards regression analysis was performed to identify factors predicting prostate-specific antigen (PSA) progression after enzalutamide treatment and logistic regression analysis for those associated with development of adverse effects.

RESULTS

PSA titers decreased by >50 % in 197 patients (57 %). The median PSA progression free survival was 163 days. Gleason score >8 (HR 2.078, 95 % CI 1.37-3.153, P = 0.00058), performance status ≥1 (HR 2.292, 95 % CI 1.463-3.592, P = 0.000296), presence of bone metastasis (HR 1.774, 95 % CI 1.019-3.090, P = 0.0429), visceral metastasis (HR 2.127, 95 % CI 1.215-3.722, P = 0.00823), previous steroid treatment (HR 1.780, 95 % CI 1.207-2.626, P = 0.00361) and docetaxel treatment (HR 1.602, 95 % CI 1.051-2.442, P = 0.0284) significantly predicted the efficacy of enzalutamide. Adverse effects, including fatigue or appetite loss, occurred in 169 patients (49 %), 48 (18 %) of whom stopped enzalutamide. Age >75 years (HR 1.980, 95 % CI 1.270-3.09, P = 0.00246) and lower enzalutamide dose (HR 0.437, 95 % CI 0.255-1.270, P = 0.00249) were significantly associated with development of adverse effects.

CONCLUSIONS

Enzalutamide treatment is effective in patients with castration-resistant prostate cancer with low Gleason scores, good performance status, without bone or visceral metastasis and no prior steroid or docetaxel treatment. Lower doses of enzalutamide decrease the incidence of adverse effects, especially in older patients.

[Advanced Adenocarcinoma of the Bladder after Augmentation Gastrocystoplasty]

A 29-year-old woman had undergone gastrocystoplasty with Mitrofanoff appendicovesicostomy for urethral trauma at 9 years of age. Since then, she was being followed up for performing clean intermittent self-catheterization at regular intervals. Twenty years after the surgery, she presented with gross hematuria. Ultrasonographic findings revealed bilateral hydronephrosis. Cystoscopy and computed tomography (CT) revealed invasive bladder cancer with pelvic lymph node metastases. A biopsy confirmed the diagnosis of adenocarcinoma with signet ring cell carcinoma. Subsequently, neo-adjuvant combination chemotherapy with TS-1 and cisplatin (CDDP) was initiated, which was followed by open radical cystectomy with extended pelvic lymphadenectomy. The tumor was found to infiltrate from the anastomotic site into the entire native bladder and histopathological diagnosis was muscle invasive adenocarcinoma with neuroendocrine differentiation and lymph node metastasis (ypT3bN2). TS-1 was continued as adjuvant chemotherapy and the patient did not have any evidence of recurrence for 12 months postoperatively.

Decreased expression of lysophosphatidylcholine (16:0/OH) in high resolution imaging mass spectrometry independently predicts biochemical recurrence after surgical treatment for prostate cancer

BACKGROUND

Human prostate cancers are highly heterogeneous, indicating a need for various novel biomarkers to predict their prognosis. Lipid metabolism affects numerous cellular processes, including cell growth, proliferation, differentiation, and motility. Direct profiling of lipids in tissue using high-resolution matrix-assisted laser desorption/ionization imaging mass spectrometry (HR-MALDI-IMS) may provide molecular details that supplement tissue morphology.

METHODS

Prostate tissue samples were obtained from 31 patients, with localized prostate cancer who underwent radical prostatectomy. The samples were assessed by HR-MALDI-IMS in positive mode, with the molecules identified by tandem mass spectrometry (MS/MS). The effect of identified molecules on prostate specific antigen recurrence free survival after radical prostatectomy was determined by Cox regression analysis and by the Kaplan-Meier method.

RESULTS

Thirteen molecules were found to be highly expressed in prostate tissue, with five being significantly lower in cancer tissue than in benign epithelium. MS/MS showed that these molecules were [lysophosphatidylcholine (LPC)(16:0/OH)+H](+), [LPC(16:0/OH)+Na](+), [LPC(16:0/OH)+K](+), [LPC(16:0/OH)+matrix+H](+), and [sphingomyelin (SM)(d18:1/16:0)+H](+). Reduced expression of LPC(16:0/OH) in cancer tissue was an independent predictor of biochemical recurrence after radical prostatectomy.

CONCLUSIONS

HR-MALDI-IMS showed that the expression of LPC(16:0/OH) and SM(d18:1/16:0) was lower in prostate cancer than in benign prostate epithelium. These differences in expression of phospholipids may predict prostate cancer aggressiveness, and provide new insights into lipid metabolism in prostate cancer.

[Clinical Characteristics of Prostate Ductal Adenocarcinoma in Kyoto University Hospital]

Prostate ductal adenocarcinoma is a rare variant of prostate cancer and considered to be more aggressive than the common acinar type of adenocarcinoma. The appropriate treatment guideline for prostate ductal adenocarcinoma has not been established. The aim of the present study was to examine the clinical characteristics and the effectiveness of treatment for prostate ductal adenocarcinoma. From 2005 to 2012, 41 patients were diagnosed to have prostate ductal adenocarcinoma in Kyoto University Hospital. The mean±SD age was 68.6±7.0 years, and the median (range) initial serum PSA level was 9.3 (3.7-217) ng/ml. Among 17 patients who underwent radical prostatectomy, 10 (58.8%) had pT3 disease and 5 (29.4%) had biochemical recurrence during median follow-up of 22.9 months. Out of 19 patients treated with definitive EBRT with endocrine therapy, 2 patients (10.5%) experienced biochemical recurrence with median follow-up of 37.3 months. Five patients were treated with endocrine therapy alone, and 2 (40.0%) of them died of prostate ductal adenocarcinoma. In conclusion, patients with prostate ductal adenocarcinoma were more likely diagnosed as locally advanced diseases than those with prostate acinar adenocarcinoma. However, for patients without metastasis, either surgery or EBRT with endocrine therapy is effective with good prognosis.

[A Case of Rapidly Progressive Metastatic Castration-Resistant Prostate Cancer : Durable Control by Early Induction of Carboplatin and Paclitaxel]

A 60-year-old man visited the previous hospital with difficulty of urination in July 2004. Serum prostate specific antigen (PSA) was 5.4 ng/ml and he was diagnosed with prostate adenocarcinoma, Gleason Score 4＋4＝8, cT1cN0M0. Although radical prostatectomy was recommended, he refused any treatment and never visited that hospital again. He was admitted to our hospital for exacerbation of dysuria with anal pain newly appeared in March 2005, when it was found that his disease had progressed to cT4N0M1b (thoracic spine, sacroiliac joint and ischium). Serum PSA decreased and the primary lesion shrunk after androgen deprivation therapy (ADT), whereas the left ischial lesion enlarged and serum carcinoembryonic antigen (CEA) and alkaline phosphatase (ALP) were elevated. For the castration-resistant progression, 30 Gy of local irradiation to the left ischial lesion and systemic chemotherapy with carboplatin (CBDCA) and paclitaxel (PTX) were administered, which led the patient to complete radiological and biochemical remission. The chemotherapy was discontinued in 2009 after the 18th course, and then ADT was also discontinued in 2010. The patient remains free from radiological or biochemical evidence of disease at the latest follow up in December 2014.

Role of IL13RA2 in Sunitinib Resistance in Clear Cell Renal Cell Carcinoma

Vascular endothelial growth factor (VEGF) and mammalian target of rapamycin are well-known therapeutic targets for renal cell carcinoma (RCC). Sunitinib is an agent that targets VEGF receptors and is considered to be a standard treatment for metastatic or unresectable clear cell RCC (ccRCC). However, ccRCC eventually develops resistance to sunitinib in most cases, and the mechanisms underlying this resistance are not fully elucidated. In the present study, we established unique primary xenograft models, KURC1 (Kyoto University Renal Cancer 1) and KURC2, from freshly isolated ccRCC specimens. The KURC1 xenograft initially responded to sunitinib treatment, however finally acquired resistance. KURC2 retained sensitivity to sunitinib for over 6 months. Comparing gene expression profiles between the two xenograft models with different sensitivity to sunitinib, we identified interleukin 13 receptor alpha 2 (IL13RA2) as a candidate molecule associated with the acquired sunitinib-resistance in ccRCC. And patients with high IL13RA2 expression in immunohistochemistry in primary ccRCC tumor tends to have sunitinib-resistant metastatic site. Next, we showed that sunitinib-sensitive 786-O cells acquired resistance in vivo when IL13RA2 was overexpressed. Conversely, shRNA-mediated knockdown of IL13RA2 successfully overcame the sunitinib-resistance in Caki-1 cells. Histopathological analyses revealed that IL13RA2 repressed sunitinib-induced apoptosis without increasing tumor vasculature in vivo. To our knowledge, this is a novel mechanism of developing resistance to sunitinib in a certain population of ccRCC, and these results indicate that IL13RA2 could be one of potential target to overcome sunitinib resistance.

Evaluation of prognostic factors after radical prostatectomy in pT3b prostate cancer patients in Japanese population

OBJECTIVE

The purpose of the current study was to evaluate prognostic factors after radical prostatectomy for prostate cancer patients with seminal vesicle invasion (pT3b) in the Japanese population.

METHODS

Between January 2005 and December 2011, 814 patients underwent radical prostatectomy without neoadjuvant hormonal therapy at our institutions. Among these patients, 31 were (3.8%) presented with pT3b. Kaplan-Meier method was used to determine biochemical recurrence-free, disease-specific and overall survival of patients in this group. Proportional hazards models were used to determine predictors of biochemical recurrence-free survival.

RESULTS

The median follow-up period was 60 months (range, 9-108 months). During follow-up, 23 patients (74.2%) experienced biochemical recurrence, and the overall 3-year probability of freedom from biochemical recurrence was 29%. However, only one patient died of the disease, and the 5-year overall survival was 92%. In multivariate analysis, age at the time of surgery was the only significant variable for predicting biochemical recurrence after radical prostatectomy (P = 0.0356, hazard ratio = 0.92, 95% confidence interval = 0.851-0.994).

CONCLUSIONS

Patients with seminal vesicle invasion of pathological specimens after radical prostatectomy have high biochemical recurrence, but the survival was favorable especially in light of current multimodal treatment regimens. However, patients with younger age at the time of surgery, in particular, should receive multimodal treatments to improve their outcome.

[A case of growing teratoma syndrome; long-term control accomplished by systemic interferon therapy with adequate local therapies]

A 31-year-old man came to our hospital with chest pain and was diagnosed to have a left testicular tumor with metastasis to the lung, and cervical, mediastinal, and retroperitoneal lymph nodes. Left orchiectomy was performed, and histological diagnosis was seminoma. Serum tumor markers were normalized after 3rd-line chemotherapy, but lymph node metastases were still enlarged. Then the cervical lymph node was excised, and histologically diagnosed as mature teratoma. Based on these results, we diagnosed this case as growing teratoma syndrome. Since the whole metastasis was too large to be completely excised, we started systemic interferon alfa-2b (IntronR A) administration. The metastasis initially responded to the therapy by 20% reduction in size and remained stable thereafter. However, the mediastinal lesion caused obstructive pneumonia, which was bronchoscopically resected. At the time of 12 years after the initial presentation, the tumors are well controlled with stable disease or only modest increase.

[Pelvic lymph node dissection in robot-assisted laparoscopic radical prostatectomy: safety and adequacy in introductory series]

To evaluate the safety and adequacy of pelvic lymph node dissection (LND) in robot-assisted laparoscopic radical prostatectomy (RALP) in an institutional introductory case series, we retrospectively reviewed the first 135 patients with clinically localized prostate cancer who underwent RALP with no LND (n＝78), limited LND (LLND, n＝40), or extended LND (ELND, n＝17). Data were collected foroperating time itemized by each surgical procedure, estimated blood loss, lymph node yield, total postoperative drainage amount, postoperative days to drainage tube removal and urethral catheter removal, perioperative complication, and postoperative hospital stay. LLND and ELND took a median of 19 (interquartile range 15-22) and 69 (60.5-91) min, respectively. Total operating time was significantly longer (p＜0.0001) for those with ELND (median 329 min ; interquartile 272-375) than those with no LND (239 ; 195-292) and LLND (281 ; 230-314). Lymph node yield was 7 (5-9) and 23 (12-30) for LLND and ELND, respectively, which was equivalent to the yield of lymph nodes dissected in open prostatectomy ashistorical and institutional control. Although total drainage amount was significantly greater and drainage tube was placed significantly longer in the ELND group, there were no significant differences in time to urethral catheter removal and postoperative hospital stay among the groups. There were no severe perioperative complications associated with LND except for prolonged lymph fistula in each case of the LLND and ELND groups. In conclusion, LND can be performed safely and adequately in introductory RALP cases.

Radiosynthesis and evaluation of N-(3,4-dimethylisoxazol-5-yl)piperazine-4-[4-(4-fluorophenyl)thiazol-2-yl]-1-[11C]carboxamide for in vivo positron emission tomography imaging of fatty acid amide hydrolase in brain

[¹¹C] DPFC is a promising PET radiotracer forin vivoimaging of fatty acid amide hydrolase in brain.

Design, synthesis and biological evaluation of small molecule-based PET radioligands for the 5-hydroxytryptamine 7 receptor

A new prospective approach for PET imaging of 5-HT₇ by a small molecule ligand.

[Presurgical treatment of axitinib reduced operation risk by downsizing the vena cava tumor thrombus in advanced renal cell carcinomas: two case reports]

In cases of advanced renal cell carcinoma with inferior vena cava (IVC) thrombus, surgical resection of both tumor and thrombus contributes to the improvement of patient's prognosis, but the risk of perioperative complication is still high. We experienced two cases of advanced renal tumors with IVC tumor thrombus down-sized by presurgical treatment of axitinib. Axitinib treatment showed a marked tumor reduction effect without any severe adverse event. We could remove both tumor and thrombus without perioperative complications. In these two cases, downsizing of IVC thrombus enabled us to reduce the extent of the surgery.

[Development of a preoperative criterion to select candidates for nerve-sparing radical prostatectomy at Kyoto University Hospital]

Neurovascular bundle (NVB) preservation is a mandatory procedure to maintain erectile function of localized prostate cancer patients after radical prostatectomy (RP). However, in terms of cancer control, indications to select appropriate patients for nerve-sparing RP are still controversial. In this study, we examined the pathological findings of RP specimens to develop a preoperative criterion for NVB preservation during RP. The study included 76 patients who underwent RP at our institution from 2006 to 2008, and we retrospectively analyzed RP specimens pathologically. The distance between NVB and foci of prostate cancer was measured in 135 prostate sides, and preoperative factors which predict the distance of ≤2 mm was evaluated. Univariate analysis showed that side-specific positive biopsy core rate ≥33.3%, side-specific maximum tumor length in biopsy core ≥5 mm and side-specific tumor involvement rate in biopsy core ≥50% was associated with the risk of the distance of ≤2 mm. Multivariate analysis revealed that side-specific positive biopsy core rate ≥33.3% was the only significant predictor of the ipsilateral NVB-tumor distance ≤2 mm (p = 0.0055, odds ratio 3.49). Based on this study, a nerve-sparing criterion of ＜33.3% side-specific percent positive biopsy core was developed at our institution. Prospective data on patients who were applied this criterion are needed to evaluate its clinical safety and feasibility.