Bone Metastatic Castration-resistant Prostate Cancer Research Articles

ISIT-QA: In Silico Imaging Trial to Evaluate a Low-Count Quantitative SPECT Method Across Multiple Scanner-Collimator Configurations for 223Ra-Based Radiopharmaceutical Therapies.

Personalized dose-based treatment planning requires accurate and reproducible noninvasive measurements to ensure safety and effectiveness. Dose estimation using SPECT is possible but challenging for alpha (α)-particle-emitting radiopharmaceutical therapy (α-RPT) because of complex γ-emission spectra, extremely low counts, and various image-degrading artifacts across a plethora of scanner-collimator configurations. Through the incorporation of physics-based considerations and skipping of the potentially lossy voxel-based reconstruction step, a recently developed projection-domain low-count quantitative SPECT (LC-QSPECT) method has the potential to provide reproducible, accurate, and precise activity concentration and dose measures across multiple scanners, as is typically the case in multicenter settings. To assess this potential, we conducted an in silico imaging trial to evaluate the LC-QSPECT method for a 223Ra-based α-RPT, with the trial recapitulating patient and imaging system variabilities. Methods: A virtual imaging trial titled In Silico Imaging Trial for Quantitation Accuracy (ISIT-QA) was designed with the objectives of evaluating the performance of the LC-QSPECT method across multiple scanner-collimator configurations and comparing performance with a conventional reconstruction-based quantification method. In this trial, we simulated 280 realistic virtual patients with bone-metastatic castration-resistant prostate cancer treated with 223Ra-based α-RPT. The trial was conducted with 9 simulated SPECT scanner-collimator configurations. The primary objective of this trial was to evaluate the reproducibility of dose estimates across multiple scanner-collimator configurations using LC-QSPECT by calculating the intraclass correlation coefficient. Additionally, we compared the reproducibility and evaluated the accuracy of both considered quantification methods across multiple scanner-collimator configurations. Finally, the repeatability of the methods was evaluated in a test-retest study. Results: In this trial, data from 268 223RaCl2 treated virtual prostate cancer patients, with a total of 2,903 lesions, were used to evaluate LC-QSPECT. LC-QSPECT provided dose estimates with good reproducibility across the 9 scanner-collimator configurations (intraclass correlation coefficient > 0.75) and high accuracy (ensemble average values of recovery coefficients ranged from 1.00 to 1.02). Compared with conventional reconstruction-based quantification, LC-QSPECT yielded significantly improved reproducibility across scanner-collimator configurations, accuracy, and test-retest repeatability ([Formula: see text] Conclusion: LC-QSPECT provides reproducible, accurate, and repeatable dose estimations in 223Ra-based α-RPT as evaluated in ISIT-QA. These findings provide a strong impetus for multicenter clinical evaluations of LC-QSPECT in dose quantification for α-RPTs.

Circulating and Imaging Biomarkers of Radium-223 Response in Metastatic Castration-Resistant Prostate Cancer.

Radium-223 improves overall survival (OS) and reduces skeletal events in patients with bone metastatic castration-resistant prostate cancer (CRPC), but relevant biomarkers are lacking. We evaluated automated bone scan index (aBSI) and circulating tumor cell (CTC) analyses as potential biomarkers of prognosis and activity. Patients with bone metastatic CRPC were enrolled on a prospective single-arm study of standard radium-223. 99mTc-MDP bone scan images at baseline, 2 months, and 6 months were quantitated using aBSI. CTCs at baseline, 1 month, and 2 months were enumerated and assessed for RNA expression of prostate cancer-specific genes using microfluidic enrichment followed by droplet digital polymerase chain reaction. The median OS was 21.3 months in 22 patients. Lower baseline aBSI and minimal change in aBSI (<+0.7) from baseline to 2 months were each associated with better OS (P = .00341 and P = .0139, respectively). The higher baseline CTC count of ≥5 CTC/7.5 mL was associated with worse OS (median, 10.1 v 32.9 months; P = .00568). CTCs declined at 2 months in four of 15 patients with detectable baseline CTCs. Among individual genes in CTCs, baseline expression of the splice variant AR-V7 was significantly associated with worse OS (hazard ratio, 5.20 [95% CI, 1.657 to 16.31]; P = .00195). Baseline detectable AR-V7, higher aBSI, and CTC count ≥5 CTC/7.5 mL continued to have a significant independent negative impact on OS after controlling for prostate-specific antigen or alkaline phosphatase. Quantitative bone scan assessment with aBSI and CTC analyses are prognostic markers in patients treated with radium-223. AR-V7 expression in CTCs is a particularly promising prognostic biomarker and warrants validation in larger cohorts.

Beyond Average: α-Particle Distribution and Dose Heterogeneity in Bone Metastatic Prostate Cancer.

α-particle emitters are emerging as a potent modality for disseminated cancer therapy because of their high linear energy transfer and localized absorbed dose profile. Despite great interest and pharmaceutical development, there is scant information on the distribution of these agents at the scale of the α-particle pathlength. We sought to determine the distribution of clinically approved [223Ra]RaCl2 in bone metastatic castration-resistant prostate cancer at this resolution, for the first time to our knowledge, to inform activity distribution and dose at the near-cell scale. Methods: Biopsy specimens and blood were collected from 7 patients 24 h after administration. 223Ra activity in each sample was recorded, and the microstructure of biopsy specimens was analyzed by micro-CT. Quantitative autoradiography and histopathology were segmented and registered with an automated procedure. Activity distributions by tissue compartment and dosimetry calculations based on the MIRD formalism were performed. Results: We revealed the activity distribution differences across and within patient samples at the macro- and microscopic scales. Microdistribution analysis confirmed localized high-activity regions in a background of low-activity tissue. We evaluated heterogeneous α-particle emission distribution concentrated at bone-tissue interfaces and calculated spatially nonuniform absorbed-dose profiles. Conclusion: Primary patient data of radiopharmaceutical therapy distribution at the small scale revealed that 223Ra uptake is nonuniform. Dose estimates present both opportunities and challenges to enhance patient outcomes and are a first step toward personalized treatment approaches and improved understanding of α-particle radiopharmaceutical therapies.

Abstract A007: Preclinical bone metastasis technology platform – Predictive evaluation of experimental therapies on bone metastasis

Abstract Most cancer deaths are due to metastases, and bone metastases are a considerable problem especially in breast and prostate cancer, being developed in 70-90% of advanced-stage patients. Despite major investments in oncology drug development, bone metastases are currently incurable and a high unmet medical need with only 5% of patients being alive 5 years after the diagnosis. Development of therapies for bone metastasis has been challenging due to lack of appropriate preclinical models available to support decision making in next phases of drug development. In the absence of clinically relevant preclinical bone metastasis models, the current strategy is to rely on preclinical efficacy data obtained with subcutaneous models that lack the clinically relevant local tissue microenvironment, which has a major impact on tumor growth. The use of clinically non-relevant models in preclinical-stage development may be one important reason for the current &amp;gt;95% failure rate of oncology drugs in clinical trials. To support predictive evaluation of therapies for bone metastatic cancers, we describe a preclinical bone metastasis technology platform for evaluating efficacy of novel therapies on bone metastases. The platform utilizes tumors growing in bone microenvironment, mimicking growth of bone metastases in patients. Syngeneic or humanized mouse models with tumor and immune cells of same species are needed for supporting development of immunotherapies, allowing interactions of tumor and immune cells in the bone metastatic microenvironment, according to the novel osteoimmuno-oncology concept. The platform provides a predictive tool for studying unique biological features associated with different types of bone metastases in cancer-type specific manner. Here we summarize case examples where results from preclinical bone metastasis studies align with clinical findings of different therapies approved or evaluated for bone metastasis. Zoledronic acid, an anti-resorptive bisphosphonate that is currently used in breast cancer patients with bone metastases to prevent cancer-induced bone loss, showed improved bone health but no effects on tumor growth. Radium-223 dichloride, an approved treatment for bone metastatic castration-resistant prostate cancer in patients, showed reduced prostate cancer growth and decreased tumor-induced bone changes. As for immunotherapies, an IDO1 inhibitor had no effects on breast cancer bone metastases and the anti-PD-1 antibody pembrolizumab had no effects on breast and prostate cancer bone metastases, predicting recent clinical findings that demonstrate lack of efficacy of anti-PD-1 in clinical prostate cancer trials. We conclude that the bone metastasis technology platform is a biologically relevant tool for preclinical evaluation of the efficacy of experimental therapies on bone metastasis, and it has been validated with positive and negative case examples, demonstrating its clinically predictive power. Citation Format: Tiina E Kähkönen, Jussi M Halleen, Jenni Bernoulli. Preclinical bone metastasis technology platform – Predictive evaluation of experimental therapies on bone metastasis [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr A007.

Prospective Assessment of Bone Metabolism Biomarkers and Survival in Metastatic Castration-resistant Prostate Cancer Patients Treated with Radium-223: The PRORADIUM Study

BackgroundRadium-223 is an active therapy option for bone metastatic castration-resistant prostate cancer (mCRPC). The lack of adequate biomarkers for patient selection and response assessment are major drawbacks for its use. ObjectiveTo assess the prognostic value of bone metabolism biomarkers (BMBs) in ra-223–treated mCRPC patients. Design, setting, and participantsA prospective cohort study of mCRPC patients treated with Ra-223 (PRORADIUM study: NCT02925702) was conducted. Outcome measurements and statistical analysisThe main objective of the study was to evaluate the association between high (≥median) baseline values in at least three bone formation (bone alkaline phosphatase [BAP] and C-terminal type-I collagen propeptide) and bone resorption (N-terminal telopeptide and pyridinoline) biomarkers, and survival. The independent prognostic value of each BMB was also assessed. The association with time to radiographic, clinical, and prostate-specific antigen (PSA) progression; time to skeletal-related events; and PSA response were secondary objectives. Multivariable (MV) Cox-regression models were evaluated. Results and limitationsA total of 169 patients were included. Of the patients, 70.4% received Ra-223 in second/third line; 144 (85.2%) were Eastern Cooperative Oncology Group 0–1, 126 (74.6%) were in pain, and 80 (47.5%) had more than ten bone metastases. Sixty-seven (39.6%) patients had elevation in at least three BMBs. The median overall survival was 12.1 mo (95% confidence interval [CI]: 10–14.7). No association was observed with other treatment-related secondary outcome parameters. Patients with high values in three or more BMBs had significantly worse survival (9.9 vs 15.2 mo; hazard ratio [HR]: 1.8 [95% CI: 1.3–2.5]; p < 0.001) in the univariate analysis, but not independent in the MV analysis (HR: 1.33; 95% CI: 0.89–2; p = 0.181). High baseline BAP was the only biomarker associated with survival in the MV model (HR: 1.89; 95% CI: 1.28–2.79; p = 0.001). Addition of BAP to the MV clinical model increased the area under the receiver operating characteristic curve 2-yr value from 0.667 to 0.755 (p = 0.003). ConclusionsBiomarkers of bone formation, especially BAP, have prognostic value in mCRPC patients treated with radium-223. Its predictive value remains to be assessed, ideally in prospective, adequately powered, randomised clinical trials. Patient summaryIn this study, we evaluate the role of bone metabolism biomarkers to help improve the use of radium-223 as therapy for advanced prostate cancer. We found that bone alkaline phosphatase may be a suitable tool.

Biomarcadores pronósticos en el uso del radio-223 en pacientes con cáncer de próstata metastásico resistente a la castración

ObjectivesEstablish basal biomarkers in patients with bone metastatic castration-resistant prostate cancer (mCRPC) treated with Ra-223 that predicted a better overall survival (OS), assess hematology toxicity and treatment response. Materials and methodsRetrospective multicenter study in 151 patients with mCRPC between 2013 and 2020. OS was assessed according to basal hemoglobin (Hb), PSA, alkaline phosphatase (AP), WHO pain scale, Eastern Cooperative Oncology Group (ECOG), number of metastatic lesions on bone scan (BS), use of protective bone agents and received. Hematological toxicities were evaluated. Treatment response was based on changes in FA and pain. ResultsMedian OS was 24months (95%CI: 16.5-31). OS in 70% of patients who received complete Ra-223 treatment (5-6 doses) was 34.9m vs. 5.8m in patients with incomplete treatment (1-4 doses). OS was longer in patients with lower PSA and AP, Hb>13g/dL, lesser bone metastasis on GO and ECOG 0-1. 52/151 patients (34%) died during follow-up. Nearly 70% of patients experienced decrease in pain and 66% reduction on AP. Half of patients had mild hematological adverse effects and only 5% had severe. ConclusionsmCRPC patients treated with Ra-223 who had Hb>13g/mL, ECOG 0-1, low AP, PSA<20ng/ml and lesser bone metastasis on BS shown a better OS with adequate safety profile.

Bone-modifying agents are protective for symptomatic skeletal events in Radium-223 treatment.

Radium-223 (Ra-223) dichloride therapy increases overall survival and delays time to the first symptomatic skeletal event (SSE) in patients with castration-resistant prostate cancer (CRPC) and bone metastases. Bone-modifying agents (BMA) reduce SSE in patients with bone metastasis, but there is little information on their use with Ra-223. This study aimed to investigate the effect of BMA on SSE in patients with bone metastatic CRPC treated with Ra-223 in real-world practice. We included 73 patients treated with Ra-223 from 10 institutions in Japan. Time to the first SSE was estimated using the Kaplan-Meier method and compared between groups using the log-rank test. We used univariate analysis to ascertain the association between variables and SSE. During a median follow-up of 12.7 months (interquartile range, 7-21.7), 12 (16.4%) patients presented SSE. Age and BMA use were different between men with and without SSE. The 1-year SSE-free survival rate from Ra-223 treatment initiation was 82.4% (95% CI, 69.4%-90.2%). BMA use was associated with favorable SSE-free survival (hazard risk, 0.23; 95% confidence interval, 0.061-0.85; p = 0.027). Two (4.7%) and seven (23.3%) patients presented symptomatic pathological bone fracture in groups with and without BMA use, respectively (p = 0.017). This study stresses the importance of BMA use in patients with CRPC and bone metastases in Ra-223 treatment.

Prognostic biomarkers in the use of radium-223 in patients with metastatic castration-resistent prostate cancer

ObjectivesThis study aimed to establish basal biomarkers in patients with bone metastatic castration-resistant prostate cancer (mCRPC) treated with 223Ra to predict better overall survival (OS), and assess hematologic toxicity and treatment response. Materials and methodsThis was a retrospective multicenter study including 151 patients with mCRPC between 2013 and 2020. OS was assessed according to basal hemoglobin (Hb), prostate-specific antigen (PSA), and alkaline phosphatase (AP) values, the World Health Organization pain scale, the Eastern Cooperative Oncology Group (ECOG) performance status scale, the number of metastatic lesions on bone scintigraphy (BS), and the use of protective bone agents and the dose received. The grade of hematological toxicities was evaluated as well as treatment response based on changes in AP and pre- and post-treatment pain. ResultsThe median OS was 24 months (95% confidence interval 16.5–31). The OS in 70% of patients who received complete (5–6 doses) versus incomplete (1–4 doses) 223Ra treatment was 34.9 vs. 5.8 months, respectively, being longer in patients with lower PSA and AP values, Hb >13 g/dl, lesser bone metastasis on bone scan and with an ECOG 0−1. 52/151 patients (34%) died during follow-up. Pain reduced in nearly 70% of patients and 66% presented a reduction in AP values. Half of the patients presented mild and 5 % severe hematological adverse effects. ConclusionsmCRPC patients treated with 223Ra with Hb values >13 g/mL, an ECOG 0−1, low AP values, PSA < 20 ng/mL and lesser bone metastasis on BS presented a better OS with an adequate safety profile.

γδ-Enriched CAR-T cell therapy for bone metastatic castrate-resistant prostate cancer.

Immune checkpoint blockade has been largely unsuccessful for the treatment of bone metastatic castrate-resistant prostate cancer (mCRPC). Here, we report a combinatorial strategy to treat mCRPC using γδ-enriched chimeric antigen receptor (CAR) T cells and zoledronate (ZOL). In a preclinical murine model of bone mCRPC, γδ CAR-T cells targeting prostate stem cell antigen (PSCA) induced a rapid and significant regression of established tumors, combined with increased survival and reduced cancer-associated bone disease. Pretreatment with ZOL, a U.S. Food and Drug Administration-approved bisphosphonate prescribed to mitigate pathological fracture in mCRPC patients, resulted in CAR-independent activation of γδ CAR-T cells, increased cytokine secretion, and enhanced antitumor efficacy. These data show that the activity of the endogenous Vγ9Vδ2 T cell receptor is preserved in CAR-T cells, allowing for dual-receptor recognition of tumor cells. Collectively, our findings support the use of γδ CAR-T cell therapy for mCRPC treatment.

The safety of radium-223 combined with new-generation hormonal agents in bone metastatic castration-resistant prostate cancer: a systematic review and network meta-analysis.

Patients with bone metastatic castration-resistant prostate cancer (mCRPC) might benefit from radium-223 (223Ra) combined with new-generation hormonal agents (NHAs) in terms of survival and quality of life (QoL). However, the safety of combination therapies remains unclear. Therefore, we aimed to perform a network meta-analysis by reviewing the literature about the combination of 223Ra with abiraterone acetate plus prednisone (AAP) or enzalutamide and to evaluate the safety of combination therapy in bone mCRPC patients. Ultimately, ten studies (2835 patients) were selected, including four randomized controlled trials (RCTs), five retrospective cohort studies, and one single-arm study. Overall, there was no difference in the incidence of fracture between the 223Ra+NHA combination group and the 223Ra monotherapy group (odds ratio [OR]: 1.46, 95% confidence interval [CI]: 0.91-2.34, P = 0.66), but the incidences in both the 223Ra+NHA combination group (OR: 3.22, 95% CI: 2.24-4.63, P < 0.01) and the 223Ra monotherapy group (OR: 2.24, 95% CI: 1.23-4.08, P < 0.01) were higher than that in the NHA monotherapy group. However, in the meta-analysis involving only RCTs, there was no difference between the 223Ra monotherapy group and the NHA monotherapy group (OR: 1.14, 95% CI: 0.22-5.95, P = 0.88), while the difference between the 223Ra+NHA combination group and the NHA monotherapy group remained significant (OR: 3.22, 95% CI: 2.24-4.63, P < 0.01). Symptomatic skeletal events (SSEs), SSE-free survival (SSE-FS), all grades of common adverse events (AEs), and ≥grade 3 AEs among all groups did not show any significant difference. Our results indicate that the combination of 223Ra with NHAs was well tolerated in bone mCRPC patients compared to 223Ra monotherapy, even though the incidence of fracture was higher in patients who received 223Ra than that among those who received NHA monotherapy. More evidence is needed to explore the safety and efficiency of 223Ra combination therapies.

Osteoprotection in patients with bone metastatic castration-resistant prostate cancer (mCRPC): real-world data from Germany, presented by d-uo

Patients with bone metastasis due to prostate cancer often present allover reduced bone mineral density. Additionally, patients with bone metastatic castration-resistant prostate cancer (mCRPC) have a relevant risk for skeletal-related events (SRE). We herein present real-world data (RWD) regarding osteoprotection in mCRPC patients with bone metastasis treated by German urologists in private practice. This is a questionnaire-based study including members of d-uo ("Deutsche Uro-Onkologen", German uro-oncologists). All patients with histologically confirmed prostate cancer seen at least once in the surveyed urology practice between July 2019 and June 2020 were included. Questions included start, type and duration of osteoprotection as well as supplementation with calcium and vitamin D. Between July 2019 and June 2020, a total of 3,692 patients with prostate cancer were seen at least once in 15 urology practices. There were 410 mCRPC patients (11.1%) with bone metastasis. Osteoprotection with denosumab or a bisphosphonate to prevent SRE was applied in 274/410 mCRPC patients (66.4%) with bone metastasis. In patients receiving osteoprotection, denosumab was chosen for 67.9% of patients and a bisphosphonate was chosen for 32.1%. Supplementation with calcium and vitamin D was performed in 93.4% of the patients. The median duration of treatment was 25.3 months for denosumab compared with 39.6 months for bisphosphonates. Patients with mCRPC with bone metastasis received osteoprotection in 2/3 of cases. Of these, 2/3 received denosumab and 1/3 received a bisphosphonate. The majority of patients were also treated with calcium and vitamin D. According to guideline recommendations regarding osteoprotection in mCRPC patients with bone metastasis, our RWD data showed some lack of guideline adherence.

Impact of Novel Hormonal Agents (Abiraterone, Enzalutamide) on the Development of Visceral and/or Brain Metastases in Patients With Bone-metastatic Castration-resistant Prostate Cancer.

The overall survival (OS) of metastatic castration-resistant prostate cancer (mCRPC) patients has improved since 2011 with the use of novel hormonal agents (NHAs). The incidence of brain metastases (mets) has been reported to increase since 2004 with the use of docetaxel, but not the incidence of visceral mets. Our objective was to study whether the use of NHAs increases the risk of developing visceral or brain mets (VBMs). mCRPC patients with mets limited to bone (bmCRPC), treated at Tours University Hospital between 2007 and 2015, were included retrospectively. The primary endpoint was to determine whether treatment with NHAs was associated with an increased incidence of VBMs. Secondary endpoints included the search for putative predictive factors to develop VBMs. On 187 bmCRPC patients included, 65 developed VBMs. VBM incidence increased in bmCRPC patients alive after 2011, compared to patients who died before (39.7 vs. 24.6%, P=.04). Meanwhile, their median OS increased from 16.3 months to 28.5 months (P=.01). The longer was the treatment with NHAs, the lower was the risk of VBMs (HR=0.96, 95% CI [0.94; 0.99]), whereas age < 70 years (HR=3.33, 95% CI [1.50; 7.40]) and low PSA level at diagnosis (HR=1.58, 95% CI [1.16; 2.15]) increased this risk. Though retrospective, our results showed an increased incidence of VBMs in bmCRPC patients after 2011. However, this was not associated with NHA exposure duration. The role of NHA exposure remains unclear and needs further investigation.

Administration of radium-223 and the prognosis in Japanese bone metastatic castration-resistant prostate cancer patients: A large database study.

BackgroundThe ALSYMPCA trial revealed radium‐223 (Ra‐223) to be a life‐prolonging agent for bone metastatic castration‐resistant prostate cancer (CRPC). However, only 2.8% of enrolled patients in that clinical trial were Asian, and no Japanese patients were enrolled. Several retrospective studies have been published concerning Japanese bone metastatic CRPC patients receiving Ra‐223. However, no study has yet reported the correlation between Ra‐223 induction and the survival in Japanese bone metastatic CRPC patients. This study investigated the effect of Ra‐223 as a life‐prolonging agent in a large Japanese healthcare fee database.MethodsA total of around 410 000 prostate cancer patients were extracted from this database, and 25 934 were diagnosed with CRPC. In these patients, the age, date of the CRPC diagnosis, date of Ra‐223 induction, and prognosis were analyzed.ResultsA total of 1628 patients received Ra‐223, and 6693 patients were diagnosed with bone metastasis CRPC, with the remaining 17 613 patients diagnosed with CRPC without bone metastasis. The patients who completed six courses of Ra‐223 showed a significantly more favorable overall and cancer‐specific survival than those who received ≤5 courses (p < 0.0001 and p < 0.0001, respectively). For time from CRPC diagnosis date to death, the Ra‐223 induction group showed a significantly more favorable prognosis with regard to both the overall and cancer‐specific survival than the bone metastatic CRPC patients without Ra‐223 (p < 0.0001 and p < 0.0001, respectively).ConclusionsBone metastatic CRPC patients who received Ra‐223 showed a significantly better prognosis than bone metastatic CPRC patients who did not receive Ra‐223.

Clinical Significance of the Highest Regional Bone Scan Index in Patients with Metastatic Castration-Resistant Prostate Cancer.

This study evaluated the clinical utility of the highest bone scan index (BSI), among other BSIs, for each bone metastatic site in patientswith bone metastatic castration-resistant prostate cancer (bmCRPC). Thirty patients, diagnosed with bmCRPC by bone scintigraphy, were included. Total BSI, the number of hot spots, and regional BSI on each hot spot from bone scintigraphy at diagnosis with bmCRPC were evaluated by VSBONE BSI®. Highest regional BSI was defined as the highest value among regional BSIs on each hot spot in each patient. Related factors to overall survival and skeletal-related events (SREs) were evaluated using the Cox proportional-hazards model. The median follow-up time from diagnosis with bmCRPC was 29.0months. During this time, 24 patients died, of which 22 patients died from prostate cancer. On univariate analysis, alkaline phosphatase (ALP) [Hazard ratio (HR): 5.96, 95% confidence interval (CI): 2.05-17.3] and highest regional BSI (HR: 2.01, 95% CI: 1.17-7.05) had significant correlation with overall survival. On multivariate analysis, ALP (HR: 4.79, 95% CI: 1.61-14.2) had significant correlation with overall survival. SREs were found in eight patients. Only the highest regional BSI (HR: 9.99, 95% CI: 2.46-40.6) significantly correlated with SREs on univariate analysis. Highest regional BSI may provide important information regarding prognosis and SREs in patientswith bmCRPC.

Health-related quality of life, psychological distress, and fatigue in metastatic castration-resistant prostate cancer patients treated with radium-223 therapy

BackgroundRadium-223 is a registered treatment option for symptomatic bone metastatic castration-resistant prostate cancer (mCRPC). Aim of this multicenter, prospective observational cohort study was to evaluate health-related quality of life (HR-QoL), psychological distress and fatigue in mCRPC patients treated with radium-223.MethodsPrimary endpoint was cancer-specific and bone metastases-related HR-QoL, as measured by the EORTC QLQ-C30 and BM-22 questionnaires. Secondary endpoints were psychological distress and fatigue, evaluated by the HADS and CIS-Fatigue questionnaires. Outcomes were analyzed for the total cohort and between subgroups (1-3 versus 4-5 versus 6 radium-223 injections). A trajectory analysis was performed to explore HR-QoL patterns over time.ResultsIn total, 122 patients were included for analysis. Baseline HR-QoL, pain intensity, psychological distress and fatigue were worse in patients who did not complete radium-223 therapy. In patients who completed therapy, stabilization of HR-QoL was perceived and psychological distress and fatigue remained stable, whereas clinically meaningful and statistically significant deterioration of HR-QoL, psychological distress and fatigue over time was observed in patients who discontinued radium-223 therapy. Trajectory analysis revealed that HR-QoL deterioration over time was more likely in patients with baseline opioid use, low hemoglobin and high alkaline phosphatase levels.ConclusionsPatients who discontinued radium-223 therapy showed worse HR-QoL, psychological distress and fatigue at baseline and more frequent deterioration of HR-QoL, psychological distress and fatigue over time when compared to patients who completed therapy. Specific attention with regard to HR-QoL during follow-up is indicated in patients with opioid use, low hemoglobin and high alkaline phosphatase levels before radium-223 therapy initiation.Clinical trial registration numberNCT04995614.

Radium-223 Utilization Patterns and Outcomes in Clinical Practice.

Radium-223 was approved for metastatic castration-resistant prostate cancer based on the ALSYMPCA trial. We characterize radium-223 treatment patterns and overall survival (OS) in a large equal access health system. We identified all men within the Veterans Affairs (VA) Healthcare System who received radium-223 between January 2013 and September 2017. Patients were followed until death or last followup. We abstracted all treatments received prior to radium; no treatments after radium were abstracted. Our primary aim was understanding practice patterns, and secondary outcome was the association between treatment pattern and OS measured using Cox models. We identified 318 bone metastatic castration-resistant prostate cancer patients who received radium-223 within the VA Healthcare System. Of these patients 277 (87%) died during followup. The 5 predominant treatment patterns that encompassed 88% of patients (279/318) were 1) androgen receptor-targeted agent (ARTA)-radium, 2) docetaxel-ARTA-radium, 3) ARTA-docetaxel-radium, 4) docetaxel-ARTA-cabazitaxel-radium and 5) radium alone. Median OS was 11 months (95% CI 9.7-12.5). Men who received ARTA-docetaxel-radium had the worst survival. All other treatments had similar outcomes. Only 42% of patients completed the full 6 injections; 25% received only 1 or 2 injections. We identified the most common radium-223 treatment patterns and their association with OS within the VA population. The better survival in ALSYMPCA (14.9 months) vs our study (11 months) along with 58% of patients not receiving the full radium-223 course suggests radium is being used later in the disease course in the real world in a more heterogeneous population.

182P Radium-223 (223Ra) in combination with exemestane and everolimus (EXE-EVE) in patients (pts) with hormone receptor-positive, human epidermal growth factor receptor 2-negative (HR+/HER2-) metastatic breast cancer (MBC) with bone metastases: A phase II study

223Ra extends overall survival (OS) in pts with bone-metastatic castration-resistant prostate cancer. This study evaluated if the addition of 223Ra to EXE-EVE provided increased benefit over EXE-EVE in pts with bone dominant HR+/HER2- MBC.

The prognostic potential of alkaline phosphatase and lactic acid dehydrogenase in bmCRPC patients without significant PSA response under enzalutamide

BackgroundIn patients with bone metastatic castration-resistant prostate cancer (bmCRPC) on systemic treatment, it is difficult to differentiate between continuous rise of prostate specific antigen (PSA) representing progression, and PSA-surge, which is followed by clinical response or stable disease. The purpose of this study was to evaluate the prognostic value of dynamic changes of alkaline phosphatase (ALP) and lactic acid dehydrogenase (LDH) levels as a predictor of clinical efficacy or therapeutic resistance of patients who do not show a sufficient initial PSA decline of ≥50% from baseline during early therapy with Enzalutamide.MethodsForty-eight men with bmCRPC on Enzalutamide 07/2010-09/2019 with initially rising PSA were analyzed. We monitored PSA, LDH and ALP at week 0, 2, 4, and every 4 weeks thereafter and analyzed the correlation between ALP rising at 12 weeks with or without LDH-normalization and the association with survival. For this we used Kaplan Meier analysis and uni- and multivariate cox-regression models.ResultsIn Kaplan-Meier analysis, ALP rising at 12 weeks with or without LDH-normalization was associated with significantly worse median progression-free survival (PFS) of 3 months vs. 5 months (Log rank P = 0.02) and 3 months vs. 5 months (P = 0.01), respectively and overall survival (OS) with 8 months vs. 15 months (P = 0.02) and 8 months vs. 17 months (P < 0.01). In univariate analysis of PFS, ALP rising at 12 weeks alone, ALP rising at 12 weeks without LDH-normalization and application of Enzalutamide after chemotherapy showed a statistically significant association towards shorter PFS (hazard ratio (HR): 0.51, P = 0.04; HR: 0.48, P = 0.03; HR: 0.48, P = 0.03). Worse OS was significantly associated with ALP rising at 12 weeks alone, ALP rising at 12 weeks without LDH-normalization, and application of Enzalutamide after chemotherapy (HR: 0.47, P = 0.02; HR: 0.36, P < 0.01; HR: 0.31, P < 0.01). In multivariate analysis only the application of Enzalutamide after chemotherapy remained an independent prognostic factor for worse OS (HR: 0.36, P = 0.01).ConclusionsDynamic changes of ALP (non-rise) and LDH (normalization) under therapy with Enzalutamide may be associated with clinical benefit, better PFS, and OS in patients with bmCRPC who do not show a PSA decline.

Ra-223 and Ethinylestradiol Combination Therapy in Castration-resistant Prostate Cancer.

Ra-223 is a therapeutic agent for bone metastatic castration-resistant prostate cancer (mCRPC). We examined the efficacy of a treatment method using Ra-223 together with ethinylestradiol (EE). Patients who received Ra-223 three or more times were included and two groups (with or without EE) were compared retrospectively. Eighteen patients were treated with Ra-223 and EE concomitantly (EstRadium therapy) and 13 patients were treated with Ra-223 alone or Ra-223 and agents other than EE (non-EstRadium therapy). The number of patients with decreased serum prostate-specific antigen level was significantly higher in the EstRadium therapy group than in the non-EstRadium therapy group (p=0.029). The combination of Ra-223 and EE, compared to Ra-223 alone, is an effective treatment option for bone mCRPC patients, in terms of PSA response.

Safety and Efficacy of 177Lutetium-PSMA-617 Radioligand Therapy Shortly after Failing 223Radium-Dichloride.

Simple SummaryThe alpha emitter 223Radium-dichloride (223Ra) and the beta emitter 177Lutetium (177Lu) targeting the prostate-specific membrane antigen (PSMA) are sequentially used for therapy of advanced bone-metastatic castration-resistant prostate cancer. Despite routine performance in patients who had received 223Ra, it is not clear whether disease sites refractory to alpha radiation can be effectively treated with 177Lu-PSMA-617. Secondly, it remains to be elucidated if therapy with 177Lu-PSMA-617 can be safely performed shortly after 223Ra, bearing in mind the myelotoxic potential of both treatments. The aim of our retrospective study was to evaluate safety and efficacy of 177Lu-PSMA-617 within less than 8 weeks after failing 223Ra. Radioligand therapy with 177Lu-PSMA-617 shortly after failing 223Ra is effective and can result in long-standing disease control even in patients with disseminated or diffuse bone involvement. Patients with oligo- and multifocal bone metastases show significantly longer overall survival with lower risk of significant hematotoxicity compared to patients with disseminated/diffuse involvement.Bone-seeking 223Radium-dichloride (223Ra) is an established treatment prolonging survival and reducing morbidity in selected patients with metastatic castration-resistant prostate cancer (mCRPC) with skeletal involvement. Radioligand therapy with 177Lutetium-PSMA-617 (177Lu-PSMA-617) has been increasingly implemented in patients with mCRPC failing conventional treatment options. In this study, the safety and efficacy of 177Lu-PSMA-617 in patients with progressive bone involvement under treatment with 223Ra was assessed. Twenty-eight men (median age 73 years, range 63–89 years) with progressive mCRPC, who started 177Lu-PSMA-617 within 8 weeks after the last 223Ra administration, received a median of 4 (IQR 3–6) and a total of 120 cycles of 223Ra and a median of 4 (IQR 2–7) cycles 177Lu-PSMA-617 with a mean treatment activity of 6.5 ± 1.2 GBq per cycle, reaching a mean cumulative activity of 30.7 ± 23.4 GBq. A PSA response (≥50% PSA decline 12 weeks after the first 177Lu-PSMA-617 cycle) was observed in 18/28 (64.3%) patients and imaging-based partial remission (PR) was observed in 11/28 (39.3%) patients. Median imaging-based progression-free survival (PFS) was 10 (95% CI, 6–14) months and median overall survival (OS) was 18 (95% CI, 14–22) months. Patients with low bone tumor burden (2–20 lesions) had a significantly longer OS (28 vs. 14 months, p < 0.045) compared to patients with a high tumor burden (>20 lesions). Grade ≥ 3 hematological toxicity was observed in six patients after their last treatment cycle with anemia, leukopenia and thrombocytopenia in 5/28 (17.9%), 4/28 (14.3%) and 6/28 (21.4%) patients, respectively. In progressive bone-metastatic mCRPC patients, prompt initiation of 177Lu-PSMA-617 after failing 223Ra is effective with an acceptable toxicity profile.