Real-world safety and effectiveness of radium-223 in patients with metastatic castration-resistant prostate cancer: Interim analyses of the prospective, observational RAPIT study.

Several life-prolonging therapies for metastatic castration-resistant prostate cancer (mCRPC) are available, including radium-223 dichloride (223Ra), which was approved based on phase 3 data demonstrating improved overall survival (OS) and a favorable safety profile. To date, real-world evidence for 223Ra use in Taiwan is from three studies of <50 patients. This observational study (NCT04232761) enrolled male patients with histologically/cytologically confirmed mCRPC with bone metastases from centers across Taiwan. 223Ra was prescribed as part of routine practice by investigators. Patients with prior 223Ra treatment were excluded. The primary objective was to assess 223Ra safety; secondary objectives evaluated efficacy parameters, including OS. Overall, 224 patients were enrolled. Most patients had an Eastern Cooperative Oncology Group performance status of 0/1 (79.0%) and ≤20 bone metastases (69.2%); no patients had visceral metastases. 223Ra was first- or second-line therapy in 23.2% and 47.7% of patients, respectively. The total proportion of patients who received 5-6 223Ra cycles was 68.8%; this proportion was greater with first-line use (84.3%) than second- (65.7%) or third-/fourth-line use (64.1%). More chemotherapy-naïve patients (61.9%) completed the 6-cycle 223Ra treatment than chemotherapy-exposed patients (56.7%). Any-grade treatment-emergent adverse events (TEAEs) and serious TEAEs occurred in 54.0% and 28.6% of patients, respectively, while 12% experienced 223Ra-related adverse events. Median OS was 15.7 months (95% confidence interval 12.13-19.51); patients receiving 5-6 223Ra injections and earlier 223Ra use had longer OS than those receiving fewer injections and later 223Ra use. 223Ra provides a well-tolerated and effective treatment for Taiwanese patients with mCRPC and bone metastases.

Safety and effectiveness of the radium-223-taxane treatment sequence in patients with metastatic castration-resistant prostate cancer in a global observational study (REASSURE).

BACKGROUND: Radium-223 and taxane chemotherapy each improve survival of patients with metastatic castration-resistant prostate cancer (mCRPC). Whether the radium-223-taxane sequence could extend survival without cumulative toxicity was explored. METHODS: The global, prospective, observational REASSURE study (NCT02141438) assessed real-world safety and effectiveness of radium-223 in patients with mCRPC. Using data from the prespecified second interim analysis (data cutoff, March 20, 2019), hematologic events and overall survival (OS) were evaluated in patients who were chemotherapy-naive at radium-223 initiation and subsequently received taxane chemotherapy starting ≤90 days ("immediate") or >90 days ("delayed") after the last radium-223 dose. RESULTS: Following radium-223 therapy, 182 patients received docetaxel (172 [95%]) and/or cabazitaxel (44 [24%]); 34 patients (19%) received both. Seventy-three patients (40%) received immediate chemotherapy and 109 patients (60%) received delayed chemotherapy. Median time from last radium-223 dose to first taxane cycle was 3.6 months (range, 0.3-28.4). Median duration of first taxane was 3.7 months (range, 0-22.0). Fourteen patients (10 in the immediate and four in the delayed subgroup) had grade 3/4 hematologic events during taxane chemotherapy, including neutropenia in two patients in the delayed subgroup and thrombocytopenia in one patient in each subgroup. Median OS was 24.3 months from radium-223 initiation and 11.8 months from start of taxane therapy. CONCLUSIONS: In real-world clinical practice settings, a heterogeneous population of patients who received sequential radium-223-taxane therapy had a low incidence of hematologic events, with a median survival of 1 year from taxane initiation. Thus, taxane chemotherapy is a feasible option for those who progress after radium-223. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov identifier NCT02141438. PLAIN LANGUAGE SUMMARY: Radium-223 and chemotherapy are treatment options for metastatic prostate cancer, which increase survival but may affect production of blood cells as a side effect. We wanted to know what would happen if patients received chemotherapy after radium-223. Among the 182 men treated with radium-223 who went on to receive chemotherapy, only two men had severe side effects affecting white blood cell production (neutropenia) during chemotherapy. On average, the 182 men lived for 2 years after starting radium-223 and 1 year after starting chemotherapy. In conclusion, patients may benefit from chemotherapy after radium-223 treatment without increasing the risk of side effects.

Radium-223 in women with hormone receptor-positive bone-metastatic breast cancer receiving endocrine therapy: pooled analysis of two international, phase 2, randomized, double-blind, placebo-controlled trials.

BACKGROUND: Most women with advanced breast cancer have skeletal metastases. Radium-223 is an alpha-emitting radionuclide that selectively targets areas of bone metastases. METHODS: Two double-blind, placebo-controlled studies of radium-223 were conducted in women with hormone receptor-positive (HR+), bone-predominant metastatic breast cancer. All patients received endocrine therapy (ET), as a single agent of the investigator's choice (Study A) or exemestane + everolimus (Study B). Patients were randomized to receive radium-223 (55 kBq/kg) or placebo intravenously every 4 weeks for six doses. Accrual was halted following unblinded interim analyses per protocol amendments, and both studies were terminated. We report pooled analyses of symptomatic skeletal event-free survival (SSE-FS; primary endpoint), radiologic progression-free survival (rPFS) and overall survival (OS; secondary), and time to bone alkaline phosphatase (ALP) progression (exploratory). RESULTS: In total, 382 patients were enrolled, and 196 SSE-FS events (70% planned total) were recorded. Hazard ratios (95% confidence intervals) and nominal p values for radium-223 + ET versus placebo + ET were: SSE-FS 0.809 (0.610-1.072), p = 0.1389; rPFS 0.956 (0.759-1.205), p = 0.7039; OS 0.889 (0.660-1.199), p = 0.4410; and time to bone ALP progression 0.593 (0.379-0.926), p = 0.0195. Radium-223- or placebo-related treatment-emergent adverse events were reported in 50.3% versus 35.1% of patients (grade 3/4: 25.7% vs. 8.5%), with fractures/bone-associated events in 23.5% versus 23.9%. CONCLUSIONS: In patients with HR+ bone-metastatic breast cancer, numeric differences favoring radium-223 + ET over placebo + ET for the primary SSE-FS endpoint were suggestive of efficacy, in line with the primary outcome measure used in the underlying phase 2 studies. No similar evidence of efficacy was observed for secondary progression or survival endpoints. Adverse events were more frequent with radium-223 + ET versus placebo + ET, but the safety profile of the combination was consistent with the safety profiles of the component drugs. Clinical trial registration numbers Study A: NCT02258464, registered October 7, 2014. Study B: NCT02258451, registered October 7, 2014.

Alpha-Emitter Radium-223 Induces STING-Dependent Pyroptosis to Trigger Robust Antitumor Immunity.

Radium-223 (223 Ra) is the first-in-class alpha-emitter to mediate tumor eradication, which is commonly thought to kill tumor cells by directly cleaving double-strand DNA. However, the immunogenic characteristics and cell death modalities triggered by 223 Ra remain unclear. Here, it is reported that the 223 Ra irradiation induces the pro-inflammatory damage-associated molecular patterns including calreticulin, HMGB1, and HSP70, hallmarks of tumor immunogenicity. Moreover, therapeutic 223 Ra retards tumor progression by triggering pyroptosis, an immunogenic cell death. Mechanically, 223 Ra-induced DNA damage leads to the activation of stimulator of interferon genes (STING)-mediated DNA sensing pathway, which is critical for NLRP3 inflammasome-dependent pyroptosis and subsequent DCs maturation as well as T cell activation. These findings establish an essential role of STING in mediating alpha-emitter 223 Ra-induced antitumor immunity, which provides the basis for the development of novel cancer therapeutic strategies and combinatory therapy.

Targeted Radium Alpha Therapy in the Era of Nanomedicine: In Vivo Results.

Targeted alpha-particle therapy using radionuclides with alpha emission is a rapidly developing area in modern cancer treatment. To selectively deliver alpha-emitting isotopes to tumors, targeting vectors, including monoclonal antibodies, peptides, small molecule inhibitors, or other biomolecules, are attached to them, which ensures specific binding to tumor-related antigens and cell surface receptors. Although earlier studies have already demonstrated the anti-tumor potential of alpha-emitting radium (Ra) isotopes-Radium-223 and Radium-224 (223/224Ra)-in the treatment of skeletal metastases, their inability to complex with target-specific moieties hindered application beyond bone targeting. To exploit the therapeutic gains of Ra across a wider spectrum of cancers, nanoparticles have recently been embraced as carriers to ensure the linkage of 223/224Ra to target-affine vectors. Exemplified by prior findings, Ra was successfully bound to several nano/microparticles, including lanthanum phosphate, nanozeolites, barium sulfate, hydroxyapatite, calcium carbonate, gypsum, celestine, or liposomes. Despite the lengthened tumor retention and the related improvement in the radiotherapeutic effect of 223/224Ra coupled to nanoparticles, the in vivo assessment of the radiolabeled nanoprobes is a prerequisite prior to clinical usage. For this purpose, experimental xenotransplant models of different cancers provide a well-suited scenario. Herein, we summarize the latest achievements with 223/224Ra-doped nanoparticles and related advances in targeted alpha radiotherapy.

Optimization of Radium-223 Treatment of Castration-resistant Prostate Cancer Based on the Burden of Skeletal Metastasis and Clinical Parameters.

BACKGROUND: Radium-223 dichloride (Ra-223) is now frequently used to treat prostate cancer that has metastasized to bone, although patient selection continues to be suboptimal for determining who will benefit most from this novel treatment modality. MATERIALS AND METHODS: Seventy-nine patients with metastatic castration-resistant prostate cancer (mCRPC) were treated with Ra-223 from 2012 to 2016. The burden of skeletal metastasis was determined for each using the Bone Scan Index (BSI) as a ratio of diseased to normal bone. Clinical, laboratory, and survival data were collected and examined for associations with BSI, and treatment tolerability was assessed. RESULTS: Chemotherapy-naïve patients were significantly more likely to complete the full course of treatment. Median follow-up was 31 months (range 0.7-38.8 months) and median overall survival was 15.4 months (range 9.5-20.6 months). Overall survival was significantly associated with findings on bone scans (P < .05). Patients with higher BSI tended toward poorer outcomes. Nearly half the patients with low baseline BSI survived 3 years or more following Ra-223 treatment. By contrast, only 20% of the patients with high baseline BSI lived for 1 year, and none lived for an additional 3. Baseline BSI was significantly associated with decreased hemoglobin, higher serum PSA and alkaline phosphatase levels, and treatment-associated reductions in platelet and absolute neutrophil counts. CONCLUSION: Our results suggest better outcomes to Ra-223 therapy for patients who are chemotherapy-naïve and who undergo treatment earlier in the course of their disease as reflected by low BSI and concordant laboratory parameters.

Management of bone metastasis in prostate cancer.

Progression of bone metastases is the primary cause of death in prostate cancer, and skeletal-related events (SREs), including pathologic fractures, spinal cord compression, radiation, or surgery to bone can impair patients' quality of life. Over the past decade, the development of cytotoxic agents, androgen-receptor-axis-targeted therapies (ARATs), and radioligand therapies has prolonged overall survival of prostate cancer patients with bone metastases and reduced the risk of SREs. The use of bone-modifying agents has also contributed to the reduced risk of SREs. Initial use of a cytotoxic agent, docetaxel, or an ARAT agent with androgen deprivation therapy (ADT) is the current approach to metastatic castration-sensitive prostate cancer. However, there is no consensus on the optimal medication for upfront use in combination with ADT, or on specific patient selection. Recently, next-generation imaging modalities, such as whole-body magnetic resonance imaging and prostate-specific membrane antigen-positron emission tomography have been utilized to detect bone metastases at an early stage. In addition, metastasis-directed therapy, such as stereotactic body radiation therapy, has been attempted. In the future, patients with bone metastatic prostate cancer will be divided into subgroups and their treatment options will be tailored to their specific characteristics.

Integrating radium-223 therapy into the management of metastatic prostate cancer care: a plain language summary.

WHAT IS THIS SUMMARY ABOUT?: Few life-prolonging treatment options are available for patients with metastatic castration-resistant prostate cancer (mCRPC). This article provides an overview of the current systemic treatments available for mCRPC and reviews studies that investigate the optimal timing for the use of radium-223. The aim is to illustrate possible systemic treatment sequences to maximize benefit from radium-223 therapy. WHAT IS METASTATIC CASTRATION-RESISTANT PROSTATE CANCER & HOW IS IT TREATED?: Prostate cancer is called mCRPC when it spreads to organs outside of the prostate (such as the lymph nodes, bones, liver, or lungs) and no longer responds to hormonal therapy. There are several treatment options available for mCRPC, such as abiraterone, enzalutamide, radium-223, docetaxel, cabazitaxel, olaparib, rucaparib, sipuleucel-T, and 177Lu-PSMA. It is important to understand the risks and benefits associated with each treatment and whether current use may have an impact on future treatment options, including eligibility in certain clinical trials. Maintaining bone health is also an important part of prostate cancer care. WHAT IS RADIUM-223?: Radium-223 is a radioactive molecule that releases strong radiation within a very small range around itself. It mainly travels to the bone where the prostate cancer has spread and kills the cancer cells in that area. Results from a clinical study named ALSYMPCA showed that men who received radium-223 lived longer in addition to having less bone pain. The most common side effects of radium-223 are nausea, vomiting, and diarrhea. Radium-223 minimally suppresses the bone marrow, which means that it slightly reduces the levels of red and white blood cells.

A phase II randomized trial of metastasis-directed therapy with alpha emitter radium-223 in men with oligometastatic castration-resistant prostate cancer (MEDAL).

BACKGROUND: The significance of metastasis-directed therapy for oligometastatic prostate cancer has been widely discussed, and targeted therapy for progressive sites is a feasible option as a multidisciplinary treatment for castration-resistant prostate cancer (CRPC). When oligometastatic CRPC with only bone metastases progresses after targeted therapy, it tends to progress as multiple bone metastases. The progression of oligometastatic CRPC after targeted therapy may be due in part to the presence of micrometastatic lesions that, though undetected on imaging, were present prior to targeted therapy. Thus the systemic treatment of micrometastases in combination with targeted therapy for progressive sites is expected to enhance the therapeutic effect. Radium-223 dichloride (radium-223) is a radiopharmaceutical that selectively binds to sites of increased bone turnover and inhibits the growth of adjacent tumor cells by emitting alpha rays. Therefore, for oligometastatic CRPC with only bone metastases, radium-223 may enhance the therapeutic effect of radiotherapy for active metastases. METHODS: This phase II, randomized trial of Metastasis-Directed therapy with ALpha emitter radium-223 in men with oligometastatic CRPC (MEDAL) is designed to assess the utility of radium-223 in combination with metastasis-directed radiotherapy in patients with oligometastatic CRPC confined to bone. In this trial, patients with oligometastatic CRPC with three or fewer bone metastases on whole-body MRI with diffusion-weighted MRI (WB-DWI) will be randomized in a 1:1 ratio to receive radiotherapy for active metastases plus radium-223 or radiotherapy for active metastases alone. The prior use of androgen receptor axis-targeted therapy and prostate-specific antigen doubling time will be used as allocation factors. The primary endpoint will be radiological progression-free survival against progression of bone metastases on WB-DWI. DISCUSSION: This will be the first randomized trial to evaluate the effect of radium-223 in combination with targeted therapy in oligometastatic CRPC patients. The combination of targeted therapy for macroscopic metastases with radiopharmaceuticals targeting micrometastasis is expected to be a promising new therapeutic strategy for patients with oligometastatic CRPC confined to bone. Trial registration Japan Registry of Clinical Trials (jRCT) (jRCTs031200358); Registered on March 1, 2021, https://jrct.niph.go.jp/latest-detail/jRCTs031200358.

Effectiveness and safety of radium-223 dichloride in patients with castration-resistant prostate cancer and bone metastases in real-world practice: A multi-institutional study.

OBJECTIVE: Radium-223 (Ra-223) dichloride is the bone-targeted radioligand therapy that prolongs overall survival (OS) in patients with bone-metastatic castration-resistant prostate cancer (CRPC). We aimed to evaluate the safety and effectiveness of this treatment in real-world practice. METHODS: We included Japanese men treated with Ra-223 for bone-metastatic CRPC from 10 institutions, retrospectively. Primary endpoint was OS. Secondary endpoint was maximum decline of alkaline phosphatase (ALP), lactate dehydrogenase, and prostate-specific antigen values, the rate of adverse events, and time to pathological fracture after Ra-223 treatment. Exploratory endpoint was the associations between clinical parameters and OS. RESULTS: In total, 73 men with bone metastatic CRPC treated with Ra-223 were enrolled. The median OS was 20.9 months. ALP levels decreased significantly from pre-treatment (p = 0.03). Anemia occurred in three (4.1%) patients. Grade ≥ 3 non-pathological fractures occurred in four (5.5%) men. Nine (12.3%) patients presented pathological fracture; 7/30 (23.3%) were in men without concomitant use of a bone-modifying agent (BMA) while 2/43 (4.7%) were in patients with concomitant BMA (p = 0.03). The median OS in patients with ≥3 cycles treatment (27.2 months, p < 0.001) or hemoglobin ≥12 g/dl (27.2 months, p = 0.001) or absence of bone pain (36.3 months, p = 0.004) was significantly longer compared to those who with ≤2 cycles or hemoglobin<12 g/dl or presence of bone paint, respectively. CONCLUSIONS: This study has shown the outcomes of Ra-223 treatment in real-world practice, where the number of treatment cycles, baseline anemia and bone pain may be useful to predict OS in Ra-223 treatment.

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

INTRODUCTION: 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. METHODS: 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. RESULTS: 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). CONCLUSION: This study stresses the importance of BMA use in patients with CRPC and bone metastases in Ra-223 treatment.

Enhanced Antitumor Efficacy of Radium-223 and Enzalutamide in the Intratibial LNCaP Prostate Cancer Model.

Radium-223 dichloride and enzalutamide are indicated for metastatic castration-resistant prostate cancer and their combination is currently being investigated in a large phase 3 clinical trial. Here, we evaluated the antitumor efficacy of radium-223, enzalutamide, and their combination in the intratibial LNCaP model mimicking prostate cancer metastasized to bone. In vitro experiments revealed that the combination of radium-223 and enzalutamide inhibited LNCaP cell proliferation and showed synergistic efficacy. The combination of radium-223 and enzalutamide also demonstrated enhanced in vivo antitumor efficacy, as determined by measuring serum PSA levels in the intratibial LNCaP model. A decreasing trend in the total area of tumor-induced abnormal bone was associated with the combination treatment. The serum levels of the bone formation marker PINP and the bone resorption marker CTX-I were lowest in the combination treatment group and markedly decreased compared with vehicle group. Concurrent administration of enzalutamide did not impair radium-223 uptake in tumor-bearing bone or the ability of radium-223 to inhibit tumor-induced abnormal bone formation. In conclusion, combination treatment with radium-223 and enzalutamide demonstrated enhanced antitumor efficacy without compromising the integrity of healthy bone. The results support the ongoing phase 3 trial of this combination.

Effect of Radium-223 on the Gut Microbiota of Prostate Cancer Patients: A Pilot Case Series Study.

Radium-223 (Ra-223) is a targeted nuclear medicine therapy for castration-resistant prostate cancer with bone metastases. Its major route of elimination is the intestine. There is overwhelming evidence that the gut microbiota is altered by ionizing radiation (IR) from radiotherapy treatments. Nevertheless, it is known that extrapolation of outcomes from radiotherapy to nuclear medicine is not straightforward. The purpose of this study was to prospectively determine the effect of Ra-223 on selected important bacteria from the gut microbiota. Stool samples from three prostate cancer patients and two healthy individuals were obtained, processed, and analysed. We specifically measured the relative change of the abundance of important bacteria, determined by the 2-ΔΔC method. We found that Ra-223 influenced the gut microbiota composition. The most relevant changes were increases of Proteobacteria and Atopobacter; and decreases of Bacteroidetes, Prevotella, Lactobacillus, Bifidobacterium, Clostridium coccoides, and Bacteroides fragilis. Additionally, our experiment confirms that the composition of gut microbiota from prostate cancer patients is altered. No significant correlation was found between each subject's gut microbiome profile and their clinical indices. Despite its limited sample, the results of this pilot study suggest that ionizing radiation from Ra-223 alters the gut microbiota composition and that the gut microbiota of prostate cancer patients has an increase of the bacteria with known prejudicial effects and a decrease of the ones with favorable effects.

Real-world outcomes of second novel hormonal therapy or radium-223 following first novel hormonal therapy for mCRPC.

Aim: To evaluate real-world clinical outcomes of radium-223 or alternative novel hormonal therapy (NHT) following first-line NHT for metastatic castration-resistant prostate cancer (mCRPC). Patients & methods: Retrospective analysis of the US Flatiron database (ClinicalTrials.gov identifier: NCT03896984). Results: In the radium-223 cohort (n = 120) versus the alternative NHT cohort (n = 226), proportionally more patients had prior symptomatic skeletal events and bone-only metastases, and first-line NHT duration was shorter. Following second-line therapy, 49 versus 39% of patients received subsequent life-prolonging therapy; of these, 47 versus 76% received taxane. Median overall survival was 10.8 versus 11.2 months. Conclusion: Real-world patients with mCRPC had similar median overall survival following second-line radium-223 or alternative NHT after first-line NHT. Many patients received subsequent therapy, with less taxane use after radium-223.

Lay abstract Patients with metastatic castration-resistant prostate cancer are often first treated with novel hormonal therapy (NHT) using abiraterone or enzalutamide. To aid decisions about what treatment to use next, we reviewed information about patients who were treated with an alternative NHT (226 patients) or the nuclear medicine radium-223 (120 patients) after the first NHT. Most patients given radium-223 had cancer that had spread to their bones only, whereas many patients given an alternative NHT had cancer in their bones and other parts of their body. Around one in four patients given radium-223 and one in five given an alternative NHT had symptoms related to their bone metastases after starting treatment. Five in every ten patients given radium-223 received further therapy, including chemotherapy in 50% of these patients, while four in every ten patients given an alternative NHT received further therapy, including chemotherapy in 75%. On average, patients lived for almost a year after starting radium-223 or an alternative NHT.

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

BACKGROUND: The 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. METHODS: A 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. RESULTS: A 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). CONCLUSIONS: Bone metastatic CRPC patients who received Ra-223 showed a significantly better prognosis than bone metastatic CPRC patients who did not receive Ra-223.

Radium-223 for metastatic, castration-resistant prostate cancer: A retrospective chart review study of real-world use in a tertiary hospital in Taiwan.

BACKGROUND: Radium-223 is an alpha-emitting, bone-targeting radiopharmaceutical that confers a survival benefit in patients with confirmed bone-metastatic, castration-resistant prostate cancer with no visceral metastases. We studied real-world use of radium-223 in eligible patients from a tertiary hospital. METHODS: We retrospectively collected clinical data of patients treated with radium-223 in Tungs' Taichung MetroHarbor Hospital by chart review. Data included biochemical parameters, pain scores, other prostate cancer treatments received and adverse events (AEs). RESULTS: Of 36 patients included in the study, 12 patients received radium-223 as first-line therapy, 11 as second-line treatment and 13 as third-line treatment. Prostate-specific antigen significantly increased from baseline in patients who received radium-223 as third-line treatment and in patients who received radium-223 post-chemotherapy. Pain scores significantly decreased when radium-223 was given as second-line and as third-line treatment. In the patients who were naive to novel anti-hormone (NAH) therapy and chemotherapy, mean alkaline phosphatase level significantly decreased from baseline. The most common AE was anemia, found in 16.7% of patients. CONCLUSION: Radium-223 had early biochemical benefits, while in the later stages of the disease, it reduced bone pain in this real-world cohort of chemotherapy-naive, NAH-naive patients, and patients with prior therapy, from a tertiary institution in Taiwan.

Ionizing Radiation from Radiopharmaceuticals and the Human Gut Microbiota: An Ex Vivo Approach.

This study aimed to determine the effect of three widely used radiopharmaceuticals with intestinal excretion on selected relevant bacteria that are part of the human gut microbiota, using an ex vivo approach. Fecal samples obtained from healthy volunteers were analyzed. Each sample was divided into four smaller aliquots. One served as the non-irradiated control. The other three were homogenized with three radiopharmaceutical solutions ([131I]NaI, [99mTc]NaTcO4, and [223Ra]RaCl2). Relative quantification of each taxa was determined by the 2-ΔΔC method, using the ribosomal gene 16S as an internal control (primers 534/385). Twelve fecal samples were analysed: three controls and nine irradiated. Our experiment showed fold changes in all analyzed taxa with all radiopharmaceuticals, but results were more significant with I-131, ranging from 1.87-83.58; whereas no relevant differences were found with Tc-99m and Ra-223, ranging from 0.98-1.58 and 0.83-1.97, respectively. This study corroborates limited existing research on how ionizing radiation changes the gut microbiota composition, providing novel data regarding the ex vivo effect of radiopharmaceuticals. Our findings justify the need for future larger scale projects.

HOW TO OPTIMALLY SEQUENCE AVAILABLE THERAPY LINES IN ADVANCED PROSTATE CANCER.

Optimal sequencing of available therapy lines in patients with advanced prostate cancer often poses quite a challenge. The guidelines are sometimes equivocal and clinical trial data are not always applicable to a particular patient. There is a difference in availability of therapy options throughout the world. In decision making, a patient as a whole should be taken into consideration, not just the stage and biology of the disease, but also patient's age, performance status, comorbidities, previous therapy lines, drug's safety profile and patient's preferences. This review article will show certain therapeutic options in the treatment of advanced hormone-sensitive prostate cancer and castration resistant prostate cancer: non- metastatic and metastatic. An attempt will be made to clarify the optimal sequencing.

Clinical outcomes, management, and treatment patterns in patients with metastatic castration-resistant prostate cancer treated with radium-223 in community compared to academic settings.

BACKGROUND: The most common site of disease in metastatic castration-resistant prostate cancer (mCRPC) is the bone. The ALSYMPCA study demonstrated that radium-223 significantly improved overall survival (OS) in mCRPC patients with symptomatic bone metastases and without visceral metastases. However, administration requires a multidisciplinary approach and an infrastructure that supports coordination of care, which may differ by practice site. We aimed to evaluate practice patterns and treatment outcomes in patients with mCRPC treated at a community practice (CP) compared with those treated at an academic center (AC). METHODS: This retrospective review included 200 adult mCRPC patients receiving radium-223 between January 2014 and June 2017. The primary endpoint, OS, was estimated from the date of radium-223 initiation. Secondary outcomes included a comparison of baseline characteristics, reasons for initiation and discontinuation of radium-223, and treatment sequencing. A subset analysis of OS based on the number of radium-223 doses and on sequencing of radium-223 either before or after chemotherapy was also conducted. RESULTS: Most patients were treated at a CP (57%). Patients treated at CP sites were significantly older (74.9 vs. 71.9 years; p = .031) and had more comorbidities (Klabunde score 1.1 vs. 0.7; p = .020) than those in an AC but initiated treatment within a shorter period of time from diagnosis of mCRPC (1.3 vs. 1.9 years; p < .001) and received a greater mean number of radium-223 doses (5.4 vs. 4.8; p = .001). There were no observed differences in OS between CPs versus ACs (21.6 vs. 20.7 months; p = .306). Overall, patients who received 5-6 doses versus 1-4 doses of radium-223 had a longer median OS (23.3 vs. 6.4 months; p < .001). The most common reason for discontinuation in patients who did not complete treatment was disease progression. Overall, 43% of patients received radium-223 monotherapy and 57% concurrently with other agents. CONCLUSIONS: Most patients received radium-223 concurrently with abiraterone acetate or enzalutamide and were able to complete 5-6 doses of radium-223. Despite differences in the populations and treatment patterns, no survival differences between patients treated in ACs versus CPs were observed. Additional real-world data are needed to validate these findings.

Safety of concomitant therapy with radium-223 and abiraterone or enzalutamide in a real-world population.

BACKGROUND: Real-world utilization and outcomes of combination therapy for men with metastatic castrate-resistant prostate cancer (mCRPC) are largely unknown. We evaluated the overall survival (OS) and skeletal-related events (SREs) among men who received radium-223 with or without concomitant abiraterone or enzalutamide in the Veterans Affairs (VA) Health System. METHODS: We reviewed charts of all mCRPC patients who received radium-223 in the VA from January 2013 to September 2017. We used Cox models to test the association between concomitant therapy versus radium-223 alone on OS and SRE. Sensitivity analyses were performed for concomitant use of denosumab/bisphosphonates. RESULTS: Three hundred and eighteen patients treated with radium-223 were identified; 116/318 (37%) received concomitant abiraterone/enzalutamide. Two hundred and seventy-seven (87%) patients died during follow-up. Patients who received concomitant therapy were younger at radium-223 initiation (median age 68 vs. 70, p = .027) and had a longer follow-up (median 29.5 vs. 17.9 months, p = .030). There was no OS benefit for those on concomitant therapy (hazard ratio [HR]: 0.87, 95% confidence interval [CI]: 0.67-1.12, p = .28). There was a trend for an increased SRE risk for patients on concomitant therapy (HR: 1.87, 95% CI: 0.96-3.61, p = .066), but this was not significant. When analyses were limited to men using bone heath agents, similar results were seen for OS (HR: 0.86, 95% CI 0.64-1.15, p = .30) and SRE (HR: 2.36, 95% CI: 0.94-5.94, p = .068). CONCLUSIONS: Despite the common use of concomitant therapy in this real-world study, there was no difference in OS among mCRPC patients. A nonsignificant increased SRE risk was observed. Further work needs to evaluate the optimal sequence, timing, and safety of combination therapies.