Radium-223 dichloride: illustrating the benefits of a multidisciplinary approach for patients with metastatic castration-resistant prostate cancer

BeTTer Outcomes Workgroup Health Quality Initiative to optimize bone health for prostate cancer patients in the British Columbia Cancer System

INTRODUCTION

Bone-targeted therapies (BTTs) are integral to the management of bone metastases in metastatic castration-resistant prostate cancer (mCRPC). BTTs vary considerably in referral and drug access pathways and optimal BTT use requires multi-specialty consultation and supervision. Health quality improvement (HQI) has become the predominant framework to improve patient care in multidisciplinary settings.

METHODS

HQI initiatives on use of BTT in mCRPC were developed and evaluated in five centers of a provincial cancer center network using Plan-Do-Study-Act (PDSA) methodology. Multidisciplinary teams (MDTs) completed a common quality assessment form and an HQI template and then implemented an HQI initiative. Feedback and findings were shared and discussed at regional events. It was subsequently determined whether to adopt, adapt, or abandon initiatives.

RESULTS

Patterns of unmet needs varied across type of BTT. Gaps in use of radium-223 were mostly referral and education issues that could be directly addressed at the local level by participating clinician teams. Conversely, most supportive BTT gaps were related to coverage and resourcing support. HQI initiatives selected by each site consisted of implementation or expansion of local MDT meetings, referral documents, databases, and improvement charters. The main HQI initiative was completed in four sites and was adapted or adopted in three. Improvements in BTT use were observed in two of three centers with data on HQI process measures.

CONCLUSIONS

Despite the overall heterogenous structure of the groups and metrics used, this study demonstrated that the PDSA framework provides the needed structure for improvements in BTT use in mCRPC across multiple sites.

Factors Influencing Outcome Post–Radium-223 Dichloride in Castrate Resistant Prostate Cancer: A Review of Some Real-World Challenges

Aim Radium-223 has been the first-approved targeted Alpha therapy agent. We retrospectively assessed different factors influencing the overall survival (OS) and patient management.

Setting and Design Thirty-two metastatic castration-resistant prostate cancer (mCRPC) patients' hematological parameters, number of cycles, performance status, and toxicities were evaluated for OS. Radium 223 dichloride (Radium-223) was administered every 4 weeks for a maximum of six cycles. Primary and secondary end points were OS, progression free survival (PFS), therapy toxicities, change in performance status, biochemical response, and skeletal-related events (SREs).

Materials and Methods Patients' median age was 77 years (range: 57–90 years) and median follow-up was 399 days (range: 5–1,761 days). A total of 163 cycles were administered in 32 patients, with 4 or less cycles in 8 patients (25%) and 5 or more cycles in 24 patients (75%). Among eight patients with 4 or less cycles, three patients died, of which two patients died due to neutropenic sepsis.

Statistical Analysis Mann–Whitney test was used to compare the cycle groups; Spearman's correlation coefficient was used to see the relation of different variables with OS. Log rank test was used for group comparison while Kaplan–Meier survivorship was used for OS.

Results Statistical correlation was seen between the number of cycles (p=0.037) and hemoglobin (p=0.028). Kaplan–Meier OS (p=0.038) was correlated with the number of cycles (≤ 4 cycles and ≥ 5 cycles). OS was 173 days in patients with one to four cycles, 226 days in five cycles, and 493 days in six cycles. Myelosuppression leading to stopping of full six cycles was seen in 7 of 32 patients (22%) and significantly correlated to inferior OS (p=0.048).

Conclusion Higher number of Radium-223 cycles was seen to be associated with better OS. Prior myelosuppression was associated with poor OS. Patients with better hematological profile were more likely to complete the maximum number of the cycles with a better OS.

Risk Scoring System for Ra-223 Discontinuation and Its Effect on Prognosis: A Retrospective Study

BACKGROUND/AIM

Radium-223 therapy prolongs overall survival in castration-resistant prostate cancer (CRPC) patients with bone metastasis. Patients who are unable to complete six courses of radium-223 therapy reportedly have a poor prognosis. This study aimed to develop a risk score using the discontinuation factors of the above therapy modality.

PATIENTS AND METHODS

Seventy patients who received radium-223 therapy for metastatic CRPC at two Japanese Institutions were evaluated. Univariate and multivariate analyses were performed to identify the discontinuation factors and determine the risk scores.

RESULTS

The median survival time was 24.3 and 9.5 months in patients who did and did not complete the therapy, respectively. Multivariate analysis revealed haemoglobin and prostate-specific antigen as key factors. A risk score was developed using these factors, and patients were stratified into three groups. The discontinuation rate and survival after radium-223 therapy were significantly different.

CONCLUSION

Our risk score may help evaluate the suitability of radium-223 in CRPC patients.

Graphene Quantum Dots for Molecular Radiotherapy: Radiolabeled Graphene Quantum Dots with Radium (223Ra) Showed Potent Effect Against Bone Cancer

The necessity of new drugs with special attention for the therapy of cancer is increasing each day. Despite their properties, alpha therapeutic radiopharmaceuticals, especially based on the use of radium (²²³Ra) are good choices, due to the highest and differential cytotoxicity, low adverse effects, and higher bioaccumulation on tumor sites. The use of graphene quantum dots as the carrier for ²²³Ra is a promising approach since graphene quantum dots has low toxicity, high biocompatibility, and adequate size for tumor penetration. In this study, we developed, characterized, radiolabeled with ²²³Ra, and evaluated in vitro and in vivo graphene quantum dots radiolabeled with radium (²²³Ra) for bone cancer. The results showed that ²²³Ra is incorporated into the graphene quantum dot following the Fajans-Paneth-Hahn Law. The cell viability showed a potent effect on osteosarcoma cells (MG63 and SAOS2) but a lower effect in normal fibroblast cells (hFB), corroborating the preferential targeting. Also, the results showed a more prominent effect on MG63 than SAOS2 cells, corroborating the targeting for more undifferentiated cells. The in vivo results demonstrated a renal excretion, associated with fecal excretion and accumulation in bone. The results corroborate the efficacy of ²²³RaGQDs and open new perspectives for the use of use ²²³RaGQDs, in several other diseases.

Targeted Palliative Radionuclide Therapy for Metastatic Bone Pain

Bone metastasis develops in multiple malignancies with a wide range of incidence. The presence of multiple bone metastases, leading to a multitude of complications and poorer prognosis. The corresponding refractory bone pain is still a challenging issue managed through multidisciplinary approaches to enhance the quality of life. Radiopharmaceuticals are mainly used in the latest courses of the disease. Bone-pain palliation with easy-to-administer radionuclides offers advantages, including simultaneous treatment of multiple metastatic foci, the repeatability and also the combination with other therapies. Several β¯- and α-emitters as well as pharmaceuticals, from the very first [⁸⁹Sr]strontium-dichloride to recently introduced [²²³Ra]radium-dichloride, are investigated to identify an optimum agent. In addition, the combination of bone-seeking radiopharmaceuticals with chemotherapy or radiotherapy has been employed to enhance the outcome. Radiopharmaceuticals demonstrate an acceptable response rate in pain relief. Nevertheless, survival benefits have been documented in only a limited number of studies. In this review, we provide an overview of bone-seeking radiopharmaceuticals used for bone-pain palliation, their effectiveness and toxicity, as well as the results of the combination with other therapies. Bone-pain palliation with radiopharmaceuticals has been employed for eight decades. However, there are still new aspects yet to be established.

Radium-223 for the treatment of bone metastases in castration-resistant prostate cancer: when and why

Radium-223 dichloride (²²³Ra) is the first, recently approved, α-particle-emitting radiopharmaceutical for the treatment of patients with bone metastases in castration-resistant prostate cancer (CRPC) and no evidence of visceral metastases. We explored MEDLINE, relevant congresses, and websites for data on ²²³Ra and prostate cancer therapies, focusing on therapeutic strategies and timing, bone metastases, and diagnostic assessment. ²²³Ra represents the only bone-targeting agent that has significantly extended patients' overall survival while reducing pain and symptomatic skeletal events. Unlike other radiopharmaceuticals, such as strontium-89 and samarium-153 EDTMP, ²²³Ra (11.4-days half-life) has shown a high biological efficiency mainly due to its short penetration range. These features potentially allow reduced bone marrow toxicity and limit undue exposure. ²²³Ra has been validated under the product name Xofigo^® by the US Food and Drug Administration and the European Medicines Agency. Patient selection, management, and treatment sequencing is recommended to be discussed in the context of a multidisciplinary environment, including oncology, urology, nuclear medicine, and radiation therapy physicians. No consensus has been achieved regarding the optimal timing and its administration as single agent or in combination with zoledronic acid or chemotherapy, so far. This review aims to provide a rationale for the use of ²²³Ra in treating metastases from CRPC, highlighting the crucial role of a multidisciplinary approach, the disputed inclusion and exclusion criteria on the basis of agencies regulations, and the value of diagnostics for therapy assessment.

Targeted alpha therapy using Radium-223: From physics to biological effects

With the advance of the use of ionizing radiation in therapy, targeted alpha therapy (TAT) has assumed an important role around the world. This kind of therapy can potentially reduce side effects caused by radiation in normal tissues and increased destructive radiobiological effects in tumor cells. However, in many countries, the use of this therapy is still in a pioneering phase. Radium-223 (²²³Ra), an alpha-emitting radionuclide, has been the first of its kind to be approved for the treatment of bone metastasis in metastatic castration-resistant prostate cancer. Nevertheless, the interaction mechanism and the direct effects of this radiopharmaceutical in tumor cells are not fully understood neither characterized at a molecular level. In fact, the ways how TAT is linked to radiobiological effects in cancer is not yet revised. Therefore, this review introduces some physical properties of TAT that leads to biological effects and links this information to the hallmarks of cancer. The authors also collected the studies developed with ²²³Ra to correlate with the three categories reviewed - properties of TAT, 5 R's of radiobiology and hallmarks of cancer- and with the promising future to this radiopharmaceutical.

Cost-effectiveness Analysis of Radium-223 Dichloride in Metastatic Castration-Resistant Prostate Cancer Patients Without Previous Chemotherapy Treatment in Spain

PURPOSE

To perform a cost-effectiveness analysis of radium-223 plus Best Supportive Care (BSC) compared to BSC in the treatment of patients with metastatic castration-resistant prostate cancer (mCRPC) and without previous docetaxel treatment in Spain.

DESIGN AND METHODS

A Markov model was developed to compare radium-223 versus BSC and to accrue the health outcomes and costs of a simulated cohort of mCRPC patients. Quality-adjusted life year (QALY) and life year (LY) were selected as health outcomes to measure the effectiveness of treatment alternatives. Main health resource use and efficacy inputs were obtained from a randomized controlled trial comparing radium-223 versus placebo. Unit costs were retrieved from Spanish databases and published sources. One-way and probabilistic sensitivity analyses were carried out to assess uncertainty.

RESULTS

Total costs and QALYs were €65 067 and 1.12 QALYs for radium-223 and €55 437 and 0.77 QALYs for BSC. Therefore, incremental costs per QALY were €27 606. The sensitivity analysis showed that with a willingness-to-pay threshold of €30 000 per QALY, radium-223 would have a probability of 48% of being cost-effective compared to BSC.

CONCLUSIONS

Although results must be assessed with caution, from the Spanish National Health System perspective and based on the results of the present analysis, radium-223 could be a suitable option of health resources' utilization for end of life mCRPC without previous docetaxel treatment, subject to a moderate level of uncertainty.

Current approaches to incorporation of radium-223 in clinical practice

Background

Treatment options for metastatic castration-resistant prostate cancer (mCRPC) have expanded in recent years and include cytotoxic agents (e.g., docetaxel and cabazitaxel), immunotherapy (e.g., sipuleucel-T), oral hormonal therapies targeting the androgen receptor axis (e.g., enzalutamide and abiraterone), and targeted alpha therapy (e.g., radium-223 dichloride (radium-223)). Although treatment guidelines have been updated to reflect the availability of new agents, it is not easy to apply them in daily clinical practice because recommendations vary depending on patient comorbidities and disease characteristics. Furthermore, therapeutic accessibility, clinical judgment, and experience affect the selection of treatment options.

Methods

In this review, we provide practical guidance for the integration of radium-223 into the management of patients with mCRPC based on our collective clinical experience, as well as the available clinical trial data.

Results

Radium-223 is a targeted alpha therapy; as a bone-seeking calcium mimetic, it accumulates in hydroxyapatite areas surrounding tumor lesions and selectively binds to the areas of increased bone turnover. Radium-223 prolongs overall survival and delays time to the first symptomatic skeletal events in men with mCRPC, and is indicated for the treatment of patients with CRPC, symptomatic bone metastases, and no known visceral metastases. We review its clinical efficacy and safety, practical guidance on identifying the appropriate patient, and recommendations for how best to educate and inform prospective patients regarding their treatment decision making. In addition, we review recent evidence for sequential and combination therapies with radium-223, provide our experiences with these treatment approaches, and discuss their implications for the future treatment of patients with mCRPC.

Conclusions

Based on our clinical experience, radium-223 should be considered relatively early in the treatment course in patients with mCRPC with bone metastases. Coordination of care among multidisciplinary team members, patients, and caregivers is essential for optimizing safe and effective treatment with all CRPC therapies.

Management of metastatic castration-resistant prostate cancer: A focus on radium-223: Opinions and suggestions from an expert multidisciplinary panel

Radium-223, a calcium mimetic bone-seeking radionuclide that selectively targets bone metastases with alpha particles, is approved for the treatment of men with metastatic castration-resistant prostate cancer (mCRPC) and symptomatic bone metastases. In patients with mCRPC, treatment with radium-223 has been associated with survival benefit, regardless of prior docetaxel use, and also has a positive impact on symptomatic skeletal events and quality of life. Radium-223 is best suited for patients with symptomatic mCRPC and bone-predominant disease and no visceral metastases, and may lead to better outcomes when given early in the course of the disease. An expert multidisciplinary panel convened in Milan, Italy to review the current best-evidence literature on radium-223 and to convey their personal expertise with the use of radium-223 and identify possible strategies for best practice. This article summarizes the best available evidence for the use of radium-223, discusses the essential role of the multidisciplinary team in delivering effective treatment for mCRPC, clarifies pre- and post-treatment evaluation and monitoring, and outlines future scenarios for radium-223 in the treatment of men with MCRPC.