Efficacy of Immediate Switching from Bicalutamide to Flutamide as Second-Line Combined Androgen Blockade

A case of metastatic prostate cancer treated with metastasectomy

In general, metastatic prostate cancer is managed medically. Here we present a patient with metastatic prostate cancer who was treated by surgical resection in addition to medical therapies. Local therapies should be considered if metastatic lesions are limited, also in cases of metastatic prostate cancer.

Nonmetastatic Castration-Resistant Prostate Cancer: Current Challenges and Trends

Prostate carcinoma is a highly prevalent biologically and clinically diverse disease, generally associated with a consistent elevation of prostate-specific antigen levels. Castration-resistant prostate cancer represents a heterogeneous clinical setting that ranges from patients with an asymptomatic prostate-specific antigen elevation after hormone blockade failure and good performance status to patients with significant debilitating symptoms and rapidly progressive disease, leading to death. Nonmetastatic castration-resistant prostate cancer is a transient disease stage defined over specific criteria established within a sensitive time period. The majority of the patients with nonmetastatic castration-resistant prostate cancer will eventually develop metastatic lesions, associated with prostate cancer-specific morbidity and mortality. However, progression to metastatic disease is a heterogeneous process still not fully understood, with studies suggesting that younger age, high Gleason score (> 7), high prostate-specific antigen levels, reduced prostate-specific antigen doubling time (< 6 months), and a rapid alkaline phosphatase rise as potentially associated factors. Although the nonmetastatic castration-resistant prostate cancer treatment landscape has substantially evolved in recent years, the disease heterogeneity makes treatment decisions for this population challenging in the effort to achieve a balance between the risk of disease progression and the toxicity of new treatments in patients who often have associated comorbidities, yet are generally asymptomatic. The present article addresses the current main challenges in nonmetastatic castration-resistant prostate cancer management, including in diagnosis, owing to the development of new imaging modalities with a direct impact in disease detection, prognostic classification, as a result of the traditionally oversimplified definition of disease aggressiveness (mainly based on prostate-specific antigen doubling time), and patient selection for the most adequate treatment.

Novel Treatment Strategy Using Second-Generation Androgen Receptor Inhibitors for Non-Metastatic Castration-Resistant Prostate Cancer

Non-metastatic castration-resistant prostate cancer (nmCRPC) is defined by a progressively rising prostate-specific antigen level, despite a castrate level of testosterone, in the absence of obvious radiologic evidence of metastatic disease on conventional imaging modalities. As a significant proportion of patients with nmCRPC develop metastatic diseases, the therapeutic goals of physicians for these patients are to delay metastasis development, preserve quality of life, and increase overall survival (OS). Since 2018, the treatment of nmCRPC has changed dramatically with the introduction of second-generation androgen receptor inhibitors, such as enzalutamide (ENZA), apalutamide (APA), and darolutamide (DARO). These drugs demonstrated substantial improvements in metastasis-free survival (MFS) and OS in phase III randomized clinical trials. In addition, these drugs have an excellent safety profile, preserve quality of life, and can delay disease-related symptoms. A recently published indirect meta-analysis reported that APA and ENZA showed better findings in MFS and that DARO had relatively fewer adverse effects. However, in the absence of a direct comparison, careful interpretation is required. Thus, APA, ENZA, and DARO should be considered the new standard drugs for treating nmCRPC.

Safety and efficacy of abiraterone acetate plus prednisolone in patients with castration-resistant prostate cancer: a prospective, observational, post-marketing surveillance study

Background

Abiraterone acetate plus prednisolone is approved to treat patients with castration-resistant prostate cancer. This study evaluated the safety and efficacy of abiraterone acetate plus prednisolone in castration-resistant prostate cancer patients with or without previous chemotherapy in a real-world setting in Japan.

Methods

This study was an observational, prospective, post-marketing surveillance. Castration-resistant prostate cancer patients, who initiated abiraterone acetate after its approval in Japan, were enrolled. Data were collected during an observation period of 12 months and a follow-up period of another 12 months. Adverse events and adverse drug reactions were evaluated for safety. Prostate-specific antigen levels and overall survival were evaluated for efficacy.

Results

From 141 participating institutions, 497 patients were registered: 492 patients including 180 chemotherapy-naïve, 311 chemotherapy-experienced and one off-label-use patient received abiraterone and were evaluated for safety. Adverse events were observed in 225/492 patients (45.7%), adverse drug reactions in 131/492 patients (26.6%) and serious adverse drug reactions in 61/492 patients (12.4%). The most commonly observed adverse drug reaction was abnormal hepatic function (6.5%), followed by hypokalemia (3.0%) and decreased appetite (2.0%). At week 12, 110/432 patients (25.5%) achieved ≥50% decrease from baseline in prostate-specific antigen, and the proportion was higher in chemotherapy-naïve patients (56/161 patients; 34.8%) compared with chemotherapy-experienced patients (54/271 patients; 19.9%, P < 0.001). Survival rates at 24 months were 68.3% (295/432 patients), 73.9% (119/161 chemotherapy-naïve patients) and 64.9% (176/271 chemotherapy-experienced patients).

Conclusions

This large-scale, real-world, post-marketing surveillance study confirmed the safety and efficacy of abiraterone acetate plus prednisolone in Japanese castration-resistant prostate cancer patients with or without previous chemotherapy.

Comparison of Current Systemic Combination Therapies for Metastatic Hormone-Sensitive Prostate Cancer and Selection of Candidates for Optimal Treatment: A Systematic Review and Bayesian Network Meta-Analysis

Objective: To compare the efficacy and safety of current systemic combination therapies for patients with mHSPC and help select candidates for optimal treatment.

Methods: Databases of MEDLINE and EMBASE, Cochrane Central Register of Controlled Trials, and Clinical Trial.gov were searched for eligible studies. Direct and network meta-analysis were conducted to compare various systemic combination therapies and the surface under the cumulative ranking curve (SUCRA) was generated for treatment ranking. Subgroup analyses were performed according to the extent of metastasis. Adverse events (AEs) were compared among the effective treatments.

Results: Ten trials with 16 publications were included in this network meta-analysis. Direct and network meta-analysis consistently suggested that androgen-deprivation therapy (ADT) combined with docetaxel, abiraterone, enzalutamide, or apalutamide could significantly improve overall survival (OS) and failure-free survival (FFS) compared to ADT alone in men with mHSPC. SUCRA analysis demonstrated the superiority of ADT plus abiraterone or enzalutamide over other therapies. Subgroup analyses indicated that additional abiraterone to ADT had the highest ranking in patients with high-volume diseases or visceral metastases and enzalutamide plus ADT outperformed other treatments in patients with low-volume diseases or without visceral metastases. Different combination therapies had variable AE profiles and ADT in addition with docetaxel or abiraterone had the highest risk of AEs.

Conclusion: ADT plus docetaxel, abiraterone, enzalutamide, or apalutamide were associated with significantly improved survival in patients with mHSPC. ADT plus abiraterone or enzalutamide appeared to be the most effective treatments. Clinicians should balance the efficacy, potential AEs, and disease status to select the optimal treatment.

An FDA Review of Drug Development in Nonmetastatic Castration-resistant Prostate Cancer

The FDA has approved three androgen receptor inhibitors-enzalutamide, apalutamide, and darolutamide-for the treatment of patients with nonmetastatic castration-resistant prostate cancer (nmCRPC). These approvals were all based on randomized, double blind, placebo-controlled trials demonstrating large improvements in metastasis-free survival (MFS) and internally consistent evidence of benefit seen across secondary endpoints. In this article, we summarize the FDA regulatory history of MFS and we describe the design, conduct, and results of the three pivotal trials supporting these important treatment options for patients with nmCRPC.

A case of advanced prostate cancer controlled for the long term by flutamide after bicalutamide failure

Currently, the early introduction of new antiandrogens is popular for castration-resistant prostate cancer (CRPC). However, adverse events can be severe and their costs are high. Here, we present a patient with CRPC in whom flutamide controlled disease progression for 10 years. This case report shows that conventional alternative antiandrogens are cost effective and are still an important option for the treatment for CRPC.

The Current Landscape of Treatment in Non-Metastatic Castration-Resistant Prostate Cancer

Non-metastatic castration-resistant prostate cancer (nmCRPC) is a heterogeneous disease with variable potential in developing into overt metastases. It is an area of increased unmet need in advanced prostate cancer and for which there had been no great treatments until recent US Food and Drug Administration (FDA) approval of 2 novel anti-androgens apalutamide and enzalutamide, which were both approved given benefit in metastasis-free survival. Early data on the use of darolutamide, another novel anti-androgen, are also explored. This review discusses the pivotal trials that led to the approval of apalutamide and enzalutamide in the nmCRPC setting and discusses the key promises and challenges with the use of these agents.