Clinical and immunologic impact of short-course enzalutamide alone and with immunotherapy in non-metastatic castration sensitive prostate cancer

Role of enzalutamide in primary and recurrent non-metastatic hormone sensitive prostate cancer: a systematic review of prospective clinical trials

INTRODUCTION

Enzalutamide, a second-generation androgen receptor inhibitor, is indicated for the treatment of metastatic disease, as well as in the treatment of non-metastatic castration resistant prostate cancer (PCa). This systematic review aims to determine outcomes and toxicity in patients with non-metastatic castration sensitive prostate cancer (nmCSPC) treated with enzalutamide in the primary or salvage settings.

METHOD

We performed a systematic review focusing on the role of Enzalutamide in the treatment of nmCSPC, using the PubMed/Medline database. Articles focusing on androgen receptor inhibitors in nmCSPC were included, while articles discussing exclusively metastatic or castration-resistant PCa were excluded.

RESULTS

The initial search retrieved 401 articles, of which 15 underwent a thorough assessment for relevance. Ultimately, 12 studies with pertinent outcomes were meticulously examined. Among these, seven studies were dedicated to the investigation of enzalutamide in the primary setting, while the remaining five publications specifically addressed its use in salvage settings. Regardless of the treatment setting, our data revealed two distinct therapeutic strategies. The first advocates for the substitution of enzalutamide for androgen deprivation therapy (ADT), based on the premise of achieving equivalent, if not superior, oncological outcomes while minimizing treatment-related toxicity. The second, adopting a more conventional approach, entails augmenting the effectiveness of ADT by incorporating enzalutamide.

CONCLUSION

Enzalutamide has considerable potential as a therapeutic strategy for nmCSPC, either used alone or in combination with ADT in the primary or in the salvage settings. The use of enzalutamide instead of ADT is an appealing strategy. However, more trials will be required to further understand the efficacy and side-effect profile of enzalutamide monotherapy.

Enzalutamide Monotherapy in the EMBARK Trial Should Be Practice-changing and Existing Data Suggest How to Mitigate Toxicity

Data from the EMBARK trial demonstrate the potential of enzalutamide monotherapy as an effective treatment for biochemically recurrent prostate cancer (BCR) without the side effects of testosterone-lowering therapy. Unfortunately, concerns about gynecomastia and how to manage this treatment-related toxicity have diminished enthusiasm. Existing data may offer an alternative scheduling strategy for enzalutamide monotherapy in BCR.

Biochemically recurrent prostate cancer in the era of EMBARK and PSMA PET imaging: everything has changed, except the patients

PURPOSE OF REVIEW

Patients with biochemically recurrent prostate cancer (BCR) after unsuccessful curative therapies frequently have an indolent and asymptomatic disease course for years. There are no prospective data showing that treating BCR improves overall survival despite new imaging strategies and emerging therapeutic data. Managing BCR requires a unique perspective in oncology that balances toxicities and disease kinetics.

RECENT FINDINGS

Prostate specific membrane antigen (PSMA) imaging is now widely available and can define subclinical disease in patients with BCR who otherwise have negative CT and bone scans, but limited data exists showing that treating PSMA-positive disease has long term impact. A phase 3 trial demonstrated that the androgen receptor pathway inhibitor enzalutamide either alone or with androgen deprivation therapy (ADT) was superior in delaying metastasis, relative to ADT alone. Survival benefits from this study remain unknown.

SUMMARY

BCR is a heterogeneous population where overtreatment may present greater risk to patients than a disease course that is often indolent. Management of BCR should be individualized based on disease kinetics. Given the unique biology of BCR, future therapeutic research should emphasize an approach that alters disease trajectory without accompanying side effects and should explore options beyond ADT-based strategies.

Advances in bio-immunotherapy for castration-resistant prostate cancer

Prostate cancer is one of the significant diseases that threaten the survival of men worldwide, with the progression of androgen deprivation therapy, become much rely on it, finally, developed into castration-resistant prostate cancer (ADT). In western countries, ranks second in incidence, and in China, with increasing lifespan, the incidence of prostate cancer is rising steadily. Although chemotherapy agents, such as taxane, have achieved some efficacy, treatment failure still occur. As sensitivity of hormone levels change, the disease can progress to castrate-resistant prostate cancer. Because of the poor efficacy of traditional surgery, endocrine therapy, radiation therapy, and chemotherapy, the treatment options for castrate-resistant prostate cancer are limited. Advanced prostate cancer can progress on immunotherapy, and thus, bio -immunotherapy targeting the unique, prostate microenvironment is an important option. In this paper, we systematically revealed the role of three types of bio-immunotherapies (immune checkpoint inhibitors, tumors, vaccines, cytokines) in castrate-resistant prostate cancer, providing a reference for clinical treatment of prostate cancer.

[Research Progress of Lung Cancer Vaccines]

With the development of medical technology, tumor vaccines as a novel precise immunotherapy approach have gradually received attention in clinical applications. Against the backdrop of the global corona virus disease 2019 (COVID-19) outbreak, vaccine technology has further advanced. Depending on the types of antigens, tumor vaccines can be divided into whole-cell vaccines, peptide vaccines, messenger ribonucleic acid (mRNA) vaccines, recombinant virus vaccines, etc. Although some tumor vaccines have been marketed and achieved certain therapeutic effects, the results of tumor vaccines in clinical trials have been unsatisfactory in the past period. With the maturation of next-generation sequencing (NGS) technology and the continuous development of bioinformatics, dynamic monitoring of the entire process of tumor subpopulation development has become a reality, which has laid a solid foundation for personalized, neoantigen-centered therapeutic tumor vaccines. This article reviews the recent developments of tumor vaccines of different types, starts with lung cancer and summarizes the achievements of tumor vaccines in clinical applications, and provides an outlook for the future development of antigen-centered tumor vaccines.
.

Identification of key enzalutamide-resistance-related genes in castration-resistant prostate cancer and verification of RAD51 functions

Patients with castration-resistant prostate cancer (CRPC) often develop drug resistance after treatment with enzalutamide. The goal of our study was to identify the key genes related to enzalutamide resistance in CRPC and to provide new gene targets for future research on improving the efficacy of enzalutamide. Differential expression genes (DEGs) associated with enzalutamide were obtained from the GSE151083 and GSE150807 datasets. We used R software, the DAVID database, protein-protein interaction networks, the Cytoscape program, and Gene Set Cancer Analysis for data analysis. The effect of RAD51 knockdown on prostate cancer (PCa) cell lines was demonstrated using Cell Counting Kit-8, clone formation, and transwell migration experiments. Six hub genes with prognostic values were screened (RAD51, BLM, DTL, RFC2, APOE, and EXO1), which were significantly associated with immune cell infiltration in PCa. High RAD51, BLM, EXO1, and RFC2 expression was associated with androgen receptor signaling pathway activation. Except for APOE, high expression of hub genes showed a significant negative correlation with the IC50 of Navitoclax and NPK76-II-72-1. RAD51 knockdown inhibited the proliferation and migration of PC3 and DU145 cell lines and promoted apoptosis. Additionally, 22Rv1 cell proliferation was more significantly inhibited with RAD51 knockdown than without RAD51 knockdown under enzalutamide treatment. Overall, six key genes associated with enzalutamide resistance were screened (RAD51, BLM, DTL, RFC2, APOE, and EXO1), which are potential therapeutic targets for enzalutamide-resistant PCa in the future.

Flutamide With or Without PROSTVAC in Non-metastatic Castration Resistant (M0) Prostate Cancer

BACKGROUND

Before 2018, there was no standard of care for non-metastatic (M0) castration resistant prostate cancer nmCRPC. Androgen receptor antagonists (ARAs) were commonly used sequentially nmCRPC.

METHODS

This was a multicenter, randomized clinical trial comparing the ARA flutamide+/-PROSTVAC, a pox viral vaccine targeting PSA that includes T-cell co-stimulatory molecules. Eligible men had negative CT and Tc99 bone scans, and rising PSA on ADT. Previous treatment with ARA was a stratification factor. Patients were also evaluated for antigen-specific immune responses using intracellular cytokine staining.

RESULTS

Thirty-three patients randomized to flutamide and 31 to flutamide+vaccine. The median age was 71.8 and 69.8 years, respectively. The median time to treatment failure after a median potential follow-up of 46.7 months was, 4.5 months (range 2-70) for flutamide alone vs. 6.9 months (2.5-40; P = .38) with flutamide+vaccine. Seven patients in each arm had a >50% PSA response. Antigen-specific responses were similar in both arms (58% of patients in flutamide alone and 56% in flutamide+vaccine). The treatments were well tolerated. The most common side effect > grade 2 was injection site reaction seen in 29/31 vaccine patients which were self-limiting.

CONCLUSION

The combination of flutamide+PROSTVAC did not improve outcomes in men with nmCRPC compared with flutamide alone. (ClinicalTrials.gov Identifier: NCT00450463).

Progression in immunotherapy for advanced prostate cancer

Prostate cancer is one of the most common malignant cancers of the male genitourinary system and has high morbidity and mortality. Currently, treatment modalities for localized prostate cancer focus mainly on radical prostatectomy or radical radiation therapy. Some patients still experience disease recurrence or progression after these treatments, while others are already at an advanced stage or have metastases at the time of diagnosis. With the continuous development and progress of medicine in recent years, immunotherapy has become a revolutionary cancer treatment, and has achieved remarkable accomplishments in the treatment of hematologic malignancies. A variety of immunotherapies have also appeared in the field of advanced prostate cancer treatment, including therapeutic vaccines and immune checkpoint therapies. Despite the discrepancy between the results of some immunotherapy studies, immunotherapy for prostate cancer has shown some initial success, especially in combination immunotherapies. Currently, immunotherapy is mainly used in advanced prostate cancer, especially in patients with metastatic castration-resistant prostate cancer. However, with the development of more clinical trials of immunotherapy, more evidence will be provided supporting the rational application of immunotherapy in the future.

Sex-biased adaptive immune regulation in cancer development and therapy

The cancer research field is finally starting to unravel the mystery behind why males have a higher incidence and mortality rate than females for nearly all cancer types of the non-reproductive systems. Here, we explain how sex - specifically sex chromosomes and sex hormones - drives differential adaptive immunity across immune-related disease states including cancer, and why males are consequently more predisposed to tumor development. We highlight emerging data on the roles of cell-intrinsic androgen receptors in driving CD8⁺ T cell dysfunction or exhaustion in the tumor microenvironment and summarize ongoing clinical efforts to determine the impact of androgen blockade on cancer immunotherapy. Finally, we outline a framework for future research in cancer biology and immuno-oncology, underscoring the importance of a holistic research approach to understanding the mechanisms of sex dimorphisms in cancer, so sex will be considered as an imperative factor for guiding treatment decisions in the future.

Recent advances in the treatment of advanced prostate cancer: maximizing existing therapies while searching for novel solutions

PURPOSE OF REVIEW

Present highlights from recent research examining treatment of advanced prostate cancer.

RECENT FINDINGS

Data are emerging that combining androgen deprivation, docetaxel, and additional androgen-receptor-targeted therapies in treatment naïve metastatic prostate cancer may be an effective strategy to improve outcomes. Genomically targeted therapies and radiopharmaceuticals continue to be evaluated in the treatment of advanced castration-resistant prostate cancer.

SUMMARY

Although no clear consensus has emerged regarding the best sequencing of available therapeutics, trial results continue to support moving available therapies earlier in the disease course. Data continue to build for novel radiopharmaceuticals soon to likely be approved for treatment of castration-resistant disease.

Study to Compare Capsule and Liquid Formulations of Enzalutamide After Single-Dose Administration Under Fasting Conditions in Prostate Cancer

LESSONS LEARNED

Limited evidence suggests an acceptable pharmacokinetic profile when enzalutamide is administered via a liquid formulation extracted from the commercially available liquid-filled soft-gelatin capsules. Tolerability may limit use in clinical practice.

BACKGROUND

Enzalutamide is an established standard-of-care treatment for advanced prostate cancer with a commercially available formulation that may be inconvenient for some patients. We proposed a study to evaluate the bioequivalence of a liquid formulation to provide an alternative method of administration.

METHODS

This was a single-dose, randomized, open-label, two-way crossover pilot bioequivalence study to compare two oral formulations of enzalutamide: four enzalutamide 40 mg liquid-filled soft-gelatin capsules (commercially available) administered whole versus enzalutamide 160 mg liquid (extracted from capsules) administered via oral syringe. To assess bioequivalence, patients were randomized to receive a single dose of one formulation, then cross over to receive the alternative formulation following a 42-day washout period; serial plasma samples were collected over the course of 24 hours, followed by collections at 3, 8, and 42 days after the dose for both formulations. Bioequivalence of the formulations was assessed via comparisons of area under the plasma concentration-time curve (AUC) calculations per U.S. Food and Drug Administration (FDA) guidance. The study also assessed the safety and tolerability of the formulations.

RESULTS

The study failed to meet proposed accrual, with only one patient enrolled, thus limiting the bioequivalence evaluation. Based on the data from a single patient, the drug exposure (measured by AUC) of enzalutamide and N-desmethyl enzalutamide (primary active metabolite) for the liquid formulation was 112% and 117%, respectively, compared with the capsule formulation. Although both formulations appeared well tolerated with no adverse events reported, the tolerability assessment questionnaire revealed an unpleasant taste of the liquid formulation.

CONCLUSION

Preliminary evidence suggests a similar pharmacokinetic profile when administering liquid extracted from enzalutamide soft-gelatin capsules compared with intact capsules in patients with prostate cancer.