Castration-Resistant Prostate Cancer

Safety and activity of radium-223 in metastatic castration-resistant prostate cancer: the experience of Istituto Nazionale dei Tumori

INTRODUCTION

Therapeutic decision-making in metastatic castration-resistant prostate cancer (mCRPC) represents an open challenge. Radium-223 is approved for patients with symptomatic bone metastases, no visceral involvement, progressing after at least 2 lines of systemic therapy, or ineligible for any other systemic treatment.

METHODS

We performed a retrospective, observational study on patients with mCRPC treated with radium-223 at our institution outside of clinical trials, to assess the safety and activity in a real-world population. Data regarding baseline patient/disease characteristics and treatment outcomes (number of cycles, treatment-related adverse events [AEs], cause of discontinuation, and best response) were collected.

RESULTS

Overall, 41 patients were treated from September 2015 to September 2018. Median age was 73 years; baseline Eastern Cooperative Oncology Group Performance Status (ECOG PS) was 0, 1, or 2 in 15%, 80%, and 5% of cases, respectively; and 3%, 41%, 44%, and 12% of patients had <6, 6-20, >20, and superscan bone lesions, respectively. A median number of 5 cycles (interquartile range 3-6) with median dose 19.52 MBq (interquartile range 12.87-24.83) was received. Treatment schedule was completed in 49% of cases; discontinuations due to AEs, disease-related death, or disease progression occurred in 24%, 33%, and 43% of patients, respectively. Any-grade AEs occurred in 73% and grade 3/4 treatment-related AEs occurred in 29% of patients, mainly anemia, decreased platelet count, and fatigue. No skeletal-related events or treatment-related deaths were recorded. After treatment, 66%, 2%, and 32% of patients had a stable, improved, or deteriorated ECOG PS versus baseline, respectively, and 24%, 61%, and 15% reported a stable, improved, or worsened pain symptom control. Post-treatment versus baseline alkaline phosphatase was reduced or stable in 46% and increased in 54% of patients, whereas prostate-specific antigen was decreased or stable in 83% and increased in 17% of patients.

CONCLUSIONS

Our study provides clinically useful real-world data on radium-223, highlighting the importance of multidisciplinary patient management to guarantee the best continuum of care for patients with mCRPC.

The Evolving Systemic Treatment Landscape for Patients with Advanced Prostate Cancer

Prostate cancer (PC) is a major health issue in developed countries, with, on the one hand, men suffering from sequelae related to unnecessary treatment of non-lethal PC, and, on the other hand, still dying because of advanced PC that progresses to castration-resistant disease. Systemic treatment is the mainstay of therapy of castration-resistant PC (CRPC). To date, a multitude of systemic agents have been tested and many of these have failed to provide a clinically meaningful benefit in CRPC, while others have been approved by the US Food and Drug Administration and/or the European Medicines Agency, including antiandrogen hormonal drugs (abiraterone, enzalutamide, apalutamide), chemotherapy (docetaxel and cabazitaxel), immunotherapy (Sipuleucel-T), and radiopharmaceutical (Radium-223) agents. In this review, systemic treatments regarded as most likely to have an impact in clinical practice are presented and discussed. In addition to the pivotal clinical studies, selected retrospective and non-randomized clinical trials are also discussed if deemed to have an impact on clinical practice or future research. A comprehensive appraisal of the expanding landscape of systemic therapies for advanced PC is provided from an expert perspective, with a focus on novel classification and diagnostic tools that have been paving the way for the development of precision medicine in PC.