Bone Metastatic Castration-resistant Prostate Research Articles

P049 - Real world lessons for optimal selection of patients with bone metastatic castration-resistant prostate cancer for radium-223 therapy

P049 - Real world lessons for optimal selection of patients with bone metastatic castration-resistant prostate cancer for radium-223 therapy

223Ra-dichloride therapy in an elderly bone metastatic castration-resistant prostate cancer patient: a case report presentation and comparison with existing literature.

223Ra-dichloride therapy in an elderly bone metastatic castration-resistant prostate cancer patient: a case report presentation and comparison with existing literature.

Biomarkers for early prognostication of outcome in patients with bone-metastatic castration-resistant prostate cancer treated with enzalutamide.

e16507 Background: Enzalutamide (Enza) prolongs survival in men with mCRPC in pre- and post chemotherapy setting. Commonly used prostate-specific antigen (PSA) may lead to non-straightforward prognosis. This is especially true for bone mCRPC (bmCRPC) in which initial bone-flare may add to difficult decision making. During other therapies, bouncing of alkaline phosphatase (ALP-Bounce) was shown as a promising surrogate for survival outcome. The purpose of this study was to evaluate the prognostic ability of ALP-Bounce compared to standard PSA and lactate dehydrogenase (LDH) after initiation of Enza. Methods: Patients with bmCRPC were included and analyzed. PSA, LDH and ALP were monitored at 2, 4, 8 and 12 weeks under very early Enza treatment. ALP-Bounce vs. no Bounce was analyzed using Kaplan-Meier estimates and uni- and multivariate (UV/MV) cox-regression models. ALP-Bounce was defined as an increase of ALP after initiation of Enza with a subsequent, significant decline below baseline during the first 8 weeks of therapy. Results: Eighty-nine men were evaluable for analysis. The median overall survival (OS) of men with ALP-Bounce was 19 months (95% confidence interval: 7.9-30.1) compared to 12 months (7.7-16.3) for no Bounce. Analysis of progression-free survival (PFS) showed similar results with 8 (0-16.3) vs. 3 months (1.9-4.1). In UV no ALP-Bounce (Hazard Ratio (HR): 1.9 (1.1-3.3); p = 0.02), no PSA-decline ≥50% (HR: 2.3 (1.5-3.7); p < 0.01) and no LDH-Normalization (HR: 2.5 (1.6-4.1); p < 0.01) were significantly associated with worse PFS. In MV only no ALP-Bounce showed a trend towards worse PFS (HR: 2.1 (0.9-4.5); p = 0.09). In UV no LDH-normalization was a significant prognosticator of poor OS (HR: 2.6 (1.6-4.2); p < 0.01) while ALP-Bounce and PSA decline ≥50% were non-prognostic. In MV no LDH-normalization remained an independent prognosticator of poor OS (HR: 2.0 (1.1.-3.5); p = 0.02). Conclusions: ALP-Bounce and LDH-Normalization may add to identification of bmCRPC-patients with favorable prognosis during early therapy with Enza. The early occurence of ALP-Bounce might be beneficial. These results have to be validated in a prospective trial.

Phase 3 prognostic analysis of the automated bone scan index (aBSI) in men with bone-metastatic castration-resistant prostate cancer (CRPC).

5006 Background: Quantitative measures of metastatic bone disease are needed in men with mCRPC. We recently demonstrated the validity/reproducibility of a computational approach to bone scan imaging that employs artificial intelligence called the automated BSI (aBSI), which quantifies the percent of skeletal mass involved by cancer. We aimed to extend the prognostic validation of aBSI in a multinational prospective phase 3 clinical study of men with bone-metastatic CRPC. Methods: Whole-body bone scans were acquired at screening in a placebo-controlled phase 3 trial of men with mCRPC and bone metastases and treated with tasquinimod/placebo (n = 1,245). The prospective aBSI biomarker analysis plan was locked in Sept 2014 prior to treatment unblinding. All scans generated at 241 trial sites in 37 countries were assessed for image quality and analyzed using the EXINI boneBSI v.2 software and were blindly associated with outcomes. Baseline aBSI was evaluated for its independent prognostic association with overall survival (OS), radiographic progression-free survival (rPFS), and symptomatic skeletal related events (SSEs). Results: The aBSI-population (721 pts) was representative of the entire trial population based on patient characteristics at screening and OS outcomes. Median aBSI was 1.07 (SE 0.05). The aBSI-population was divided into quartiles (n = 180-181) with aBSI-levels of 0 - 0.3 (Q1); > 0.3 - 1.1 (Q2); > 1.1 - 4.0 (Q3); and > 4.0 (Q4) and median OS ranging from 35 months (Q1) to 13 mo (Q4) (p < 0.0001). Baseline aBSI was significantly associated with OS (HR 1.2 per doubling of BSI; p < 0.0001) and remained independently associated with OS after adjustment for treatment, PSA, CRP, LDH and albumin. Baseline aBSI was also strongly associated with rPFS (p = 0.0005), time to symptomatic progression (p < 0.0001), and time to SSE (p = 0.001). Conclusions: This analysis represents the first phase 3 evaluation of aBSI as a clinically validated prognostic biomarker for OS, rPFS, and SSEs in men with bone-metastatic CRPC, providing independent prognostic information over commonly measured clinical characteristics. Clinical trial information: NCT01234311.

The treatment patterns of castration-resistant prostate cancer in Japan, including symptomatic skeletal events and associated treatment and healthcare resource use

ABSTRACTBackground: Real-world treatment patterns of bone metastatic castration-resistant prostate cancer (mCRPC) in Japan were examined, focusing on treatment patterns and resource use differences attributed to symptomatic skeletal events (SSEs).Methods: Urologists (N = 176) provided retrospective chart data for patients with mCRPC (N = 445) via online surveys. Descriptive analyses and chi-square tests evaluated treatment patterns and their differences by SSE presence; generalized linear mixed models examined healthcare resource utilization differences as a function of SSEs.Results: Patients were on average 73.6 years old (SD = 8.3), diagnosed with prostate cancer 5.1 years (SD = 6.2), castration-resistant 2.3 years (SD=2.0), and had 7.9 bone metastases sites (SD=12.4). Novel anti-hormones showed increased adoption as mCRPC treatment. Simultaneously, luteinizing hormone-releasing hormone (LHRH) agonist/antagonist use was common (43.6% of patients in 1st line), even as CRPC treatment had started. SSEs were uncommon (2–3% per treatment line; 5% at any time), but were associated with increased opioids, strontium-89, bisphosphonates, and NSAIDs use, plus increased healthcare visits (all p < .05).Conclusions: LHRH agonist/antagonist treatment combinations remain the mCRPC treatment mainstay in Japan. However, novel anti-hormone therapies are becoming well-accepted in practice. SSEs were associated with increased healthcare resource and analgesic use, highlighting the need for efficient symptom management.

Effects of radium-223 (Ra-223) with docetaxel versus docetaxel alone on bone biomarkers in patients with bone-metastatic castration-resistant prostate cancer (CRPC): A phase I/IIa clinical trial.

154 Background: Interactions between metastatic prostate cancer cells, osteoblasts, osteoclasts, and other participants in bone metabolism are complex and result in pathologic bone physiology. Ra-223, a targeted alpha therapy, accumulates at sites of bone metastases and prolongs survival. Ra-223 and docetaxel (D), acting through different mechanisms of action, may have beneficial effects on bone pathophysiology and tumor microenvironment. Prior data suggest treatment with Ra-223 results in favorable alterations in bone biomarkers that are associated with survival. Methods: 53 patients with progressing CRPC and ≥ 2 bone metastases were randomized 2:1 to Ra-223 (55 kBq/kg q6wk × 5) + D (60 mg/m2 q3wk × 10) versus D (75 mg/m2 q3wk with step-down option to 60 mg/m2). Bone resorption (CTX-1, ICTP) and formation (P1NP, bALP) markers, tALP, and PSA were analyzed at wk 19 (after 3 Ra-223 injections) and 3 wk after end of treatment (EOT). Results: Mean % change at wk 19 and EOT are shown (Table). tALP, bALP, P1NP, and PSA declined early during treatment, reaching an average of &gt; 30% decline from baseline by wk 19 in both arms. Mean % declines were greater in the Ra-223 + D versus the D-alone arm at wk 19 and EOT. Bone resorption markers CTX-1 and ICTP showed little decline at wk 19. Conclusions: Ra-223 + D patients had greater % decline in tALP and in bone formation markers bALP and P1NP. Due to small patient numbers and preliminary data, further analysis and correlation with clinical outcomes in a larger study is warranted. Clinical trial information: NCT01106352. [Table: see text]

Factors predicting skeletal-related events in patients with bone metastatic castration-resistant prostate cancer.

Skeletal-related events (SREs) are common complications of bone metastatic castration-resistant prostate cancer (mCRPC). To the authors' knowledge, there are limited data regarding which factors predict SREs. The authors identified risk factors for SREs in men with bone mCRPC using characteristics commonly available in the medical record. Data from 454 patients with nonmetastatic CRPC were identified from 2 Veteran Affairs Medical Centers from 2000 through 2013. Among these men, 233 (51%) developed bone metastases during follow-up and represented the study cohort. First occurrence of an SRE was abstracted from the medical records. A stepwise multivariable Cox model was used to select the strongest predictors of time to SRE. The median age of the patients at the time of diagnosis of bone mCRPC was 75 years (interquartile range, 68-81 years), and there were 153 nonblack patients (66%). During follow-up (median, 7.8 months [interquartile range, 2.9-18.3 months]), 88 patients (38%) had an SRE. On univariable analysis, more recent year of metastasis (hazard ratio [HR], 0.91), prostate-specific antigen doubling time of ≥9 months versus <9 months (HR, 0.50), and bone pain (HR, 3.34) were all found to be associated with SRE risk. On multivariable analysis, year of metastasis (HR, 0.93), biopsy Gleason score of 7 versus ≤6 (HR, 1.74), radiotherapy as the primary localized treatment versus none (HR, 2.33), and bone pain (HR, 3.64) were associated with SRE risk. The area under the curve for a multivariable model based upon these risk factors was 0.744. The authors identified several significant predictors of SREs among men with mCRPC. In particular, men with bone pain are at high risk of an SRE. If confirmed, future trials should focus on prolonging life and reducing SRE risk in patients with mCRPC with bone pain. Cancer 2017;123:1528-1535. © 2017 American Cancer Society.

Epidermal Growth Factor Receptor Status in Circulating Tumor Cells as a Predictive Biomarker of Sensitivity in Castration-Resistant Prostate Cancer Patients Treated with Docetaxel Chemotherapy.

Objective: We examined whether epidermal growth factor receptor (EGFR) expression in circulating tumor cells (CTCs) can be used to predict survival in a population of bone-metastatic castration-resistant prostate cancer (mCRPC) patients treated with docetaxel chemotherapy. Methods: All patients with mCRPC who had experienced treatment failure with androgen-deprivation therapy and had received docetaxel chemotherapy were eligible. CTCs and EGFR expression in CTCs were enumerated with the CellSearch System in whole blood. This system is a semi-automated system that detects and enriches epithelial cells from whole blood using an EpCAM antibody-based immunomagnetic capture. In addition, the EGFR-positive CTCs were assessed using CellSearch® Tumor Phenotyping Reagent EGFR. Results: The median CTC count at baseline before starting trial treatment was eight CTCs per 7.5 mL of blood (range 0–184). There were 37 patients (61.7%) who had ≥5 CTCs, with median overall survival of 11.5 months compared with 20.0 months for 23 patients (38.3%) with <5 CTCs (p < 0.001). A total of 15 patients (40.5%, 15/37) with five or more CTCs were subjected to automated immunofluorescence staining and cell sorting for EGFR protein. Patients with EGFR-positive CTCs had a shorter overall survival (OS) (5.5 months) than patients with EGFR-negative CTCs (20.0 months). CTCs, EGFR-positive CTCs, and alkaline phosphatase (ALP) were independent predictors of overall survival time (p = 0.002, p < 0.001, and p = 0.017, respectively). Conclusion: CTCs may be an independent predictor of OS in CRPC treated with docetaxel chemotherapy. The EGFR expression detected in CTCs was important for assessing the response to chemotherapy and predicting disease outcome.

Radium-223: Insight and Perspectives in Bone-metastatic Castration-resistant Prostate Cancer.

223Ra prolongs overall survival in symptomatic patients affected by multiple bone-metastatic castration-resistant prostatic cancer, without visceral or nodal involvement. However, many questions remain about its mechanisms of action, and its use in clinical practice is still unresolved. First of all, what is the main target of alpha-particle emission, that is, in what way does it influences the tumor microenvironment? When is the best timing in the course of the disease, extending its use to asymptomatic low-volume or even to the micrometastatic phase? What are suitable biomarkers to be employed as prognostic factors and response indicators? Which associations with other drugs and their sequence can offer the best results, and is their effect additive or synergistic? Ultimately, in the current climate of spending review, what is the optimal cost and benefit ratio regarding available treatments? In this review, we tried to answer these questions by analyzing the available scientific literature.

Isotope Therapy for Castrate-Resistant Prostate Cancer

Radiopharmaceuticals used in the treatment of castrate-resistant prostate cancer are reviewed herein with an emphasis on sequential and combination therapies. Four bone-seeking radiopharmaceuticals had been approved in the United States. Three of these are β-emitters (phosphorus-32, strontium-89, samarium-153-ethylenediaminetetramethylene-phosphonic acid) that are approved for palliative purposes. One α-emitter (radium-223 [Ra]) is approved for prolongation of survival in bone metastatic castrate-resistant prostate cancer. Bone-seeking radiopharmaceuticals have been used in combination therapy with chemotherapy, hormones, and bisphosphonates for decades. Current combinations and clinical trials are primarily focused on Ra, given that overall survival benefit is associated with this radionuclide. Phase III trials with Ra were conducted in combination with a variety of standard hormonal therapies, bisphosphonates, and external beam radiation. Since the phase III Ra trials have been conducted, additional experience has been obtained with newer hormonal therapies such as abiraterone and enzalutamide, as well as with chemotherapies such as docetaxel. These therapies have been used both in combination with Ra and in sequence. Insights have arisen under each condition.A continuous evolution of radiopharmaceuticals is anticipated as these agents evolve in 2 distinct ways. First, current agents will evolve in combination with both current and emerging therapies, to create a better integrated and optimized approach. Second, radiopharmaceuticals that target the tumor (regardless of location) will continuously evolve. Therapies restricted to bone have inherent shortcomings, even in bone-tropic malignancies such as prostate cancer. Preliminary data with prostate-specific membrane antigen targeted β-emitters such as lutetium-177 are promising but need further evaluation. Prostate-specific membrane antigen targeted α-emitters are also in development. Given the molecular heterogeneity of tumor cells and the many shortcomings of molecularly targeted therapy, radiopharmaceuticals represent an attractive alternative approach given their capability of direct antitumor effects as well as their capability of microenvironmental disruption.

Do skeletal-related events predict overall survival in men with metastatic castration-resistant prostate cancer?

Skeletal-related events (SREs) including pathologic fracture, spinal cord compression, radiation to bone and surgery to bone, are common in men with bone metastatic castration-resistant prostate cancer (mCRPC). Men with mCRPC are at high risk of death. Whether SREs predict mortality is unclear. We tested the association between SREs and overall survival (OS) in a multiethnic cohort with bone mCRPC, controlling for key covariates unavailable in claims data such as bone pain, number of bone metastases and PSA doubling time (PSADT). We collected data on 233 men diagnosed with nonmetastatic castration-resistant prostate cancer (CRPC) in 2000-2013 at two Veterans Affairs hospitals who later progressed to bone metastases. First occurrence of SRE and OS were collected from the medical records. Cox models were used to test the association between SRE and OS, treating SRE as a time-dependent variable. We adjusted for age, year, race, treatment center, biopsy Gleason, primary treatment to the prostate, PSA, PSADT, months from androgen deprivation therapy to CRPC, months from CRPC to metastasis and number of bone metastases at initial bone metastasis diagnosis. In a secondary analysis, we also adjusted for bone pain. During follow-up, 88 (38%) patients had an SRE and 198 (85%) died. After adjusting for risk factors, SRE was associated with increased mortality (hazard ratio (HR)=1.67; 95% confidence interval (CI) 1.22-2.30; P=0.001). When bone pain was added to the model, the association of SREs and OS was attenuated, but remained significant (HR=1.42; 95% CI 1.01-1.99; P=0.042). SREs are associated with increased mortality in men with bone mCRPC. Further studies on the impact of preventing SREs to increase survival are warranted.

Dynamic changes of alkaline phosphatase are strongly associated with PSA-decline and predict best clinical benefit earlier than PSA-changes under therapy with abiraterone acetate in bone metastatic castration resistant prostate cancer.

BackgroundSignificant progress in treatment of metastatic castration resistant prostate cancer (mCRPC) has been made. Biomarkers to tailor therapy are scarce. To facilitate decision-making we evaluated dynamic changes of alkaline phosphatase (ALP), lactate dehydrogenase (LDH) and prostate specific antigen (PSA) under therapy with Abiraterone.MethodsMen with bone mCRPC (bmCRPC) on Abiraterone 12/2009-01/2014 were analyzed. Dynamic ALP-, LDH- and PSA-changes were analyzed as predictors of best clinical benefit and overall survival (OS) with logistic-regression, Cox-regression and Kaplan-Meier-analysis.ResultsThirty-nine pre- and 45 post-chemotherapy patients with a median follow up of 14.0 months were analyzed. ALP-Bouncing can be observed very early during therapy with Abiraterone. ALP-Bouncing is defined as rapidly rising ALP-levels independent of baseline ALP during the first 2–4 weeks of Abiraterone-therapy with subsequent equally marked decline to pretreatment levels or better within 8 weeks of therapy, preceding potentially delayed PSA-decline. In univariate analysis failure of PSA-reduction ≥50 % and failure of ALP-Bouncing were the strongest predictors of progressive disease (p = 0.003 and 0.021). Rising ALP at 12 weeks, no PSA-reduction ≥50 % and no ALP-Bouncing were strongest predictors of poor OS, (all p < 0.001). Kaplan-Meier-analysis showed worse OS for rising ALP at 12 weeks, no PSA-reduction ≥50 % and no ALP-Bouncing (p < 0.001). In subgroup-analysis of oligosymptomatic patients all parameters remained significant predictors of poor OS, with no PSA-reduction ≥50 % and rising ALP at 12 weeks being the strongest (p < 0.001). In multivariate analysis PSA-reduction ≥50 % remained an independent predictor of OS for the whole cohort and for the oligosymptomatic subgroup (both p = 0.014). No patient with ALP-Bouncing had PD for best clinical benefit. Patients with rising ALP at 12 weeks had no further benefit of Abiraterone.ConclusionsDynamic changes of ALP, LDH and PSA during Abiraterone-therapy are associated with best clinical benefit and OS in bmCRPC. ALP-Bouncing occurring earlier than PSA-changes as well as prior to equivocal imaging results and rising ALP at 12 weeks under Abiraterone may help to decide whether to discontinue Abiraterone. An external validation of these findings on a prospective cohort is planned.Electronic supplementary materialThe online version of this article (doi:10.1186/s12885-016-2260-y) contains supplementary material, which is available to authorized users.

Randomized phase-2 study of sipuleucel-T with or without radium-223 in men with asymptomatic/minimally symptomatic bone-metastatic castrate-resistant prostate cancer (CRPC).

TPS5076 Background: Sipuleucel-T is an autologous cellular immunotherapy indicated for men with asymptomatic/minimally symptomatic metastatic CRPC. Recent analysis of immune responses in men treate...

MP46-20 CARMUSTINE AND SELENITE COMBINATION THERAPY EFFECTIVELY INHIBITS CASTRATION RESISTANT PROSTATE CANCER IN PRECLINICAL MODELS

INTRODUCTION AND OBJECTIVES: Radium-223 dichloride (Xofigo, Bayer HealthCare Pharmaceuticals) is a first in class alpha particle emitter producing a survival benefit for patients with late stage bone metastatic castrate resistant prostate cancer (bmCRPC). Dosed at 45 kBq per kg every 4 weeks for 6 total injections, the bone seeking radionuclide delivers 4 high-energy alpha particles across a path length of only several cell diameters. Mechanism of action for the survival benefit is not fully understood, hampering our ability to best utilize this novel therapy. We tested Ra in naive and bone metastatic models of disease, to define the whole body and sub-organ distribution of the radionuclide. Our results shed light on important considerations for preand clinical evaluation of Ra for personalized radiotherapy. METHODS: Animals were dosed with 45 kBq per kg of clinical grade Ra. Whole body distribution was monitored by gamma counting in multiple skeletally-mature murine models. Organ and whole body retention were assessed at 1, 4 and 24 h. Detailed Ra microdistribution was assessed by cross-modality imaging of whole body and long bone autoradiography, histochemistry and alpha-camera imaging of whole-mount, undecalcified tissues. Uptake dependence and radiobiological effect of Ra on bone morphology were evaluated by 10 mm isotropic resolution mCT (SkyScan). RESULTS: In contrast to previous preclinical work, our distribution studies recapitulate the planar scintigraphy results in man (Carrasquillo et al., EJNMMI, 2013), with Ra accumulation observed in bowel, stomach, and spleen. In particular, whole-body autoradiography demonstrated the radioisotope bound to the contents of the digestive organs. Kinetic analysis revealed rapid clearance from the blood, and delayed clearance from kidney and intestine. In the bone, Ra predominantly localized to the growth plates; largely sparing the marrow cavity. In bone metastatic models, including the osteoblastic LNCaP, Ra uptake was significantly lower than that in the epiphyseal plate (Figure). CONCLUSIONS: Here we provide greater understanding of the in vivo biological fate of this radiopharmaceutical, with significant implications for enhanced dosing strategies in bmCRPC.

MP87-12 RADIUM-223 DICHLORIDE IN EXPANDED-ACCESS SETTING IN THE UNITED STATES: OVERALL AND CONCURRENT EXPERIENCE WITH ABIRATERONE OR ENZALUTAMIDE

You have accessJournal of UrologyProstate Cancer: Advanced III1 Apr 2015MP87-12 RADIUM-223 DICHLORIDE IN EXPANDED-ACCESS SETTING IN THE UNITED STATES: OVERALL AND CONCURRENT EXPERIENCE WITH ABIRATERONE OR ENZALUTAMIDE Neal Shore, Nicholas Vogelzang, Daniel Fernandez, Michael Morris, Andrei Iagaru, Alan Brown, Christopher Sweeney, Matthew R. Smith, Adam P. Dicker, Yu-Ning Wong, Keith Bangerter, Jeremy Gratt, Oana Petrenciuc, and Oliver Sartor Neal ShoreNeal Shore More articles by this author , Nicholas VogelzangNicholas Vogelzang More articles by this author , Daniel FernandezDaniel Fernandez More articles by this author , Michael MorrisMichael Morris More articles by this author , Andrei IagaruAndrei Iagaru More articles by this author , Alan BrownAlan Brown More articles by this author , Christopher SweeneyChristopher Sweeney More articles by this author , Matthew R. SmithMatthew R. Smith More articles by this author , Adam P. DickerAdam P. Dicker More articles by this author , Yu-Ning WongYu-Ning Wong More articles by this author , Keith BangerterKeith Bangerter More articles by this author , Jeremy GrattJeremy Gratt More articles by this author , Oana PetrenciucOana Petrenciuc More articles by this author , and Oliver SartorOliver Sartor More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2015.02.1957AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES The aim of this prospective expanded-access program (EAP) was to monitor acute and long-term safety of radium-223 dichloride (Ra-223). Herein we provide experience with Ra-223. METHODS Patients with symptomatic bone-metastatic castration-resistant prostate cancer/hormone-resistant prostate cancer in the United States who were ineligible for or had prior docetaxel were enrolled. Treatment included Ra-223 50 kBq/kg intravenously q4wk for 6 cycles with concomitant standard of care. Primary end points were Eastern Cooperative Oncology Group performance score, symptomatic skeletal events (SSEs), and treatment-emergent adverse events (TEAEs). Exploratory end points included overall survival (OS). Analyses were conducted to assess safety and OS for the whole cohort and subgroups using concurrent enzalutamide (Enza) or abiraterone (Abi). RESULTS 184 patients were treated. Of these 120 (65%) had prior and 35 (19%) had concurrent Abi; 59 (32%) had prior and 25 (14%) had concurrent Enza. Baseline characteristics were generally balanced including the concurrent subgroups. 8 deaths occurred during treatment, none related to Ra-223. TEAEs occurring at ≥ 10% were anemia, fatigue, diarrhea, and nausea. The rate of grade 3-5 TEAEs was similar across concurrent (Abi 37%, Enza 36%) and prior subgroups (Abi 43%, Enza 42%) vs overall (41%). Median OS was 17 months. CONCLUSIONS In heavily pretreated patients in this EAP setting, Ra-223 was well tolerated with a longer survival than previously seen in phase 3 ALSYMPCA (15 mo). Concurrently administered with either Abi or Enza, Ra-223 was well tolerated, adding important information on concurrent use of Ra-223 and newer hormonal agents. Abi N = 35 Abi N = 35 Enza N = 25 Enza N = 25 Overall N = 184 Overall N = 184 n % n % n % Age, median, y 68 70 70 Race, white 31 89 23 92 169 92 Weight, median, kg 87 90 86 ECOG ≤ 1 35 100 24 96 165 90 Total ALP ≥ 220 U/L 8 23 8 32 56 30 Current bisphosphonate, yes 6 17 6 24 18 10 Prior docetaxel, yes 14 40 15 60 109 59 Pts receiving all 6 injections 20 57 15 60 81 44 © 2015 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 193Issue 4SApril 2015Page: e1088-e1089 Advertisement Copyright & Permissions© 2015 by American Urological Association Education and Research, Inc.MetricsAuthor Information Neal Shore More articles by this author Nicholas Vogelzang More articles by this author Daniel Fernandez More articles by this author Michael Morris More articles by this author Andrei Iagaru More articles by this author Alan Brown More articles by this author Christopher Sweeney More articles by this author Matthew R. Smith More articles by this author Adam P. Dicker More articles by this author Yu-Ning Wong More articles by this author Keith Bangerter More articles by this author Jeremy Gratt More articles by this author Oana Petrenciuc More articles by this author Oliver Sartor More articles by this author Expand All Advertisement Advertisement PDF DownloadLoading ...

Dynamic changes of alkaline phosphatase as surrogate for best clinical benefit and overall survival during very early abiraterone therapy compared to PSA-changes in bone metastatic castration resistant prostate cancer.

260 Background: Significant progress in treatment of metastatic castration resistant prostate cancer (mCRPC) has been made. Biomarkers to tailor therapy are scarce. To facilitate decision-making we evaluated dynamic changes of alkaline phosphatase (ALP), lactate dehydrogenase (LDH) and prostate specific antigen (PSA) under Abiraterone acetate (AA). ALP-Bouncing can be observed during very early AA-therapy. Methods: Men with bone mCRPC (bmCRPC) on AA 12/2009-01/2014 were analyzed. Dynamic ALP-, LDH- and PSA-changes were analyzed as predictors of best clinical benefit (BCB) and overall survival (OS) with logistic-regression, Cox-regression and Kaplan-Meier-analysis. Results: 39 pre- and 45 post-chemotherapy patients with median follow up of 14.0 months were analyzed. In univariate analysis failure of PSA-reduction ≥50% (PSA-red≥50%) and failure of ALP-Bouncing were the strongest predictors of progressive disease (p=0.003 and 0.021). Rising ALP at 12 weeks (ALP12), no PSA-red≥50% and no ALP-Bouncing were strongest predictors of poor OS, (all p&lt;0.001). Kaplan-Meier-analysis showed worse OS for ALP12, no PSA-red≥50% and no ALP-Bouncing (p&lt;0.001). In subgroup-analysis of oligosymptomatic patients all parameters remained significant predictors of poor OS, no PSA-red≥50% and ALP12 being the strongest (p&lt;0.001). In multivariate analysis PSA-red≥50% remained independent predictor of OS for the whole cohort and for the oligosymptomatic subgroup (p=0.014). No patient with ALP-Bouncing had PD for BCB. Patients with ALP12 had no further benefit of AA. Conclusions: Dynamic changes of ALP, LDH and PSA during AA-therapy are associated with BCB and OS in bmCRPC. ALP-Bouncing occurring earlier than PSA-changes and rising ALP12 under AA may help to decide whether to discontinue AA.

Treatment of skeletal metastases with 223Ra-chloride

Bone metastases cause significant morbidity to patients with prostate cancer, the most commonly diagnosed solid cancer in men. In the last decade, the approach to metastatic castrate-resistant prostate cancer has evolved remarkably, with approval of multiple new medications with survival benefit. We review the radiobiology and phases of development of 223Ra (radium), an α-emitter radiopharmaceutical, and discuss the clinical implications of its use and its future role in the treatment of prostate cancer. A review of the literature was performed through searches of PubMed and Medline databases and related links in these databases, along with recently published abstracts from major medical meetings. 223Ra is an α-emitter, with high affinity to areas of bone metastases. α-Particles have high energy and short range, causing cytotoxicity to targeted cancer cells without affecting surrounding normal tissues. It has been proven to prolong overall survival, delay symptomatic skeletal events, and improve quality of life, while having a minimal toxicity profile. 223Ra is effective and safe in the treatment of bone metastatic castration-resistant prostate cancer. Additional studies are planned to assess the efficacy of 223Ra in combination with other agents known to be active in advanced prostate cancer.

Current and emerging therapies for bone metastatic castration-resistant prostate cancer.

A paucity of therapeutic options is available to treat men with metastatic castration-resistant prostate cancer (mCRPC). However, recent developments in our understanding of the disease have resulted in several new therapies that show promise in improving overall survival rates in this patient population. Agents approved for use in the United States and those undergoing clinical trials for the treatment of mCRPC are reviewed. Recent contributions to the understanding of prostate biology and bone metastasis are discussed as well as how the underlying mechanisms may represent opportunities for therapeutic intervention. New challenges to delivering effective mCRPC treatment will also be examined. New and emerging treatments that target androgen synthesis and utilization or the microenvironment may improve overall survival rates for men diagnosed with mCRPC. Determining how factors derived from the primary tumor can promote the development of premetastatic niches and how prostate cancer cells parasitize niches in the bone microenvironment, thus remaining dormant and protected from systemic therapy, could yield new therapies to treat mCRPC. Challenges such as intratumoral heterogeneity and patient selection can potentially be circumvented via computational biology approaches. The emergence of novel treatments for mCRPC, combined with improved patient stratification and optimized therapy sequencing, suggests that significant gains may be made in terms of overall survival rates for men diagnosed with this form of cancer.

Abstract A43: Novel prostate cancer patient-derived xenograft models of bone metastatic castrate-resistant prostate cancer

Abstract Prostate cancer metastasis to bone occurs in 50-90% of men with advanced disease for which there is no cure. Bone metastasis leads to debilitating fractures and severe bone pain. It is associated with disease progression, therapy resistance, poor prognosis, and rapid decline. Androgen ablation therapy is standard of care for advanced prostate cancer, however, the role of androgens in bone metastatic prostate cancer is not understood. The effects of anti-androgens as seen on bone scans can also be inconsistent with the biochemical PSA response. There are few pre-clinical models to understand the interaction between the bone microenvironment and prostate cancer. It is essential to understand the unique interaction of prostate cancer with the bone environment and to develop novel therapies that target these pathways. Here we report the development of novel patient-derived intra-femoral xenograft models of prostate bone metastatic cancer. METHODS: Surgical prostate cancer bone metastasis specimens were transplanted by direct injection into the femurs of Rag2-/-γc-/- mice or sub-cutaneously into the right flank. Patient-derived xenograft (PDX) tumors that grew out were analyzed for prostate cancer biomarker expression using quantitative RT-PCR and immunohistochemistry. Bone lesion formation was measured using micro-computed tomography (μCT). RESULTS: Prostate cancer surgical bone metastasis specimens have been collected from which we have established new serially transplantable, prostate cancer bone metastasis xenograft models – PCSD1, PCSD4 and PCSD5. PCSD1 (Prostate Cancer San Diego 1) was molecularly characterized as advanced, luminal epithelial-type prostate cancer. PCSD1 intra-femoral xenografts formed mixed osteoblastic/osteolytic lesions that closely mimicked those of the patient. Treatment with the anti-androgen, bicalutamide, did not inhibit intra-femoral PCSD1 xenograft growth although there was a decrease in PSA as seen in some patients treated with anti-androgen who had discordant PSA and bone scan tests. CONCLUSION: PCSD1, PCSD4 and PCSD5 are new patient-derived prostate cancer bone metastasis-derived xenograft models. PCSD1 xenograft model closely recapitulates the mixed osteolytic/osteoblastic bone metastatic lesions seen in patients, and we are using it to develop novel therapies for inhibiting prostate cancer growth in the bone-niche. Citation Format: Christina Jamieson, Christina Wu, Amy Strasner, Jason R. Woo, Michelle Muldong, Young B. Jeong, Michael A. Liss, Omer Raheem, Tomonori Yamaguchi, Heather Leu, Deborah Marshall, Sheldon Morris, Nicholas A. Cacalano, Koichi Masuda, Catriona H.M. Jamieson, Anna A. Kulidjian, Christopher J. Kane. Novel prostate cancer patient-derived xenograft models of bone metastatic castrate-resistant prostate cancer. [abstract]. In: Proceedings of the AACR Special Conference: The Translational Impact of Model Organisms in Cancer; Nov 5-8, 2013; San Diego, CA. Philadelphia (PA): AACR; Mol Cancer Res 2014;12(11 Suppl):Abstract nr A43.

Bone-targeting radiopharmaceuticals for the treatment of bone-metastatic castration-resistant prostate cancer: exploring the implications of new data.

Clinical features of patients with castration-resistant prostate cancer (CRPC) are characterized by a high incidence of bone metastases, which are associated with impairment of quality of life, pain, skeletal-related events (SREs), and a negative impact on prognosis. Advances in the understanding of cancer cell-bone stroma interactions and molecular mechanisms have recently permitted the development of new agents. We review the merits, applications, and limitations of emerging data sets on bone-metastatic CRPC with a focus on radium-223, an α-emitting radiopharmaceutical, and its use in therapy for this disease. References for this review were identified through searches of PubMed and Medline databases, and only papers published in English were considered. Related links in the databases were reviewed, along with relevant published guidelines, recently published abstracts from major medical meetings, and transcripts from a recent round table of clinical investigators. Prior to radium-223, available bone-targeted therapies demonstrated the ability to delay SREs and palliate bone pain in patients with metastatic CRPC but without evidence of improvement in overall survival (OS). In a randomized controlled phase III trial, radium-223 demonstrated the ability to improve OS and delay SREs in docetaxel-pretreated or docetaxel-unfit men with symptomatic bone-metastatic CRPC and was not associated with significantly more grade 3 or 4 adverse events than placebo. Radium-223 has a targeted effect on bone metastases in CRPC and has an important role in docetaxel-pretreated or docetaxel-unfit men with symptomatic bone-metastatic CRPC.