Efficacy and safety of PARP inhibitors in metastatic castration-resistant prostate cancer: A systematic review and meta-analysis of clinical trials

Current Evidence on Cabazitaxel for Prostate Cancer Therapy: A Narrative Review

The incidence of prostate cancer (PC) has recently increased in Japan. Androgen deprivation therapy (ADT) has been a key treatment in patients with castration-sensitive PC (CSPC); however, resistance typically emerges through multiple mechanisms, leading to metastatic castration-resistant PC (mCRPC). Taxane-based therapy (i.e., docetaxel, cabazitaxel) has been standard care in patients with mCRPC. New evidence supporting the addition of androgen receptor signaling inhibitors (ARSIs, e.g., enzalutamide, abiraterone) to docetaxel and ADT for patients with metastatic CSPC (mCSPC) raises questions about the role of taxane-based therapies and their optimal sequencing, as well as how to identify patients who may benefit from taxane-based therapy. Here we review the evidence on taxane-based therapy, including cabazitaxel, in the treatment of PC, with a focus on clinical and real-world evidence from Japan. Cabazitaxel has proven effective for patients with mCRPC who have a history of ARSI and docetaxel use, and it is preferable to a second alternative ARSI, as indicated in the CARD study. The safety profile of cabazitaxel (particularly, the incidence of neutropenia) can be managed through prophylactic use of granulocyte colony-stimulating factor, as well as a lower dosage and possibly variation of the dosage interval. However, a certain dose intensity is required because neutropenia has been identified as a potential prognostic indicator for treatment effectiveness. In the ARSI era for mCSPC, evidence on mCRPC treatment sequencing is limited. A better understanding of PC biology and the collection of real-world data is essential for effective treatment and improved safety-benefit outcomes.

Impact of Body Mass Index on Survival After Docetaxel Chemotherapy for Metastatic Castration-resistant Prostate Cancer

Background/Aim

Several recent studies, varying in design and the number of baseline parameters analyzed, suggest that a lower body mass index (BMI) is associated with shorter survival in men beginning treatment for metastatic castration-resistant prostate cancer (MCRPC), including treatments such as docetaxel. This study aimed to analyze the impact of BMI and numerous covariates on survival in a homogeneously treated cohort of Caucasian men who received first-line docetaxel for MCRPC.

Patients and Methods

This retrospective analysis included 112 consecutive patients managed between 2009 and 2023. Comorbidity, medications, and blood tests were included. Both, uni- and multivariate tests were performed.

Results

The median age of the patients was 70 years with a median BMI of 26.8 kg/m2. Most patients were free from serious comorbidities, had bone-only metastases, and experienced metachronous development of metastases. Hemoglobin values were significantly lower in patients with lower BMI (median 11.9 versus 13.0 g/dl, p=0.001). Lean patients had numerically shorter survival compared to overweight/obese patients (median 11.8 versus 19.4 months, p=0.15). In multivariate analysis of prognostic factors, only three baseline parameters retained statistical significance: serum lactate dehydrogenase (p=0.03), hemoglobin (p=0.007), and the presence of non-bone metastases (p=0.004).

Conclusion

An interaction between BMI and hemoglobin was present in metastatic castration-resistant prostate cancer patients after docetaxel chemotherapy, explaining the observed survival difference between lean and overweight/obese patients. Comorbidities and medications had no significant impact on survival in this population with limited prognosis (median survival 16.1 months).

Efficacy and safety of PARP inhibitors in prostate cancer: An umbrella review of systematic reviews and meta-analyses

Prostate cancer is a significant cause of cancer-related deaths in men. Poly (ADP-ribose) polymerase inhibitors (PARPi) have been shown to improve progression-free survival, especially in patients with BRCA1/2 mutations and deficiencies in homologous recombination repair (HRR). We conducted systematic reviews and meta-analyses and found that PARPi, combined with androgen receptor inhibitors, significantly improved overall survival (OS) and progression-free survival (PFS) in BRCA1/2-mutant and HRR-deficient patients. PARPi therapies increased the incidence of adverse events (AEs), including fatigue, nausea, anemia, neutropenia, and thrombocytopenia. Among different PARP inhibitors, Olaparib, Talazoparib, and Rucaparib demonstrated the strongest efficacy in improving OS and PFS but were also linked to higher rates of AEs. Combination therapies with PARPi and hormonal treatments proved more effective than monotherapy, especially in genetically targeted subgroups like BRCA1/2-mutant patients. This umbrella review demonstrates that PARPi treatment significantly improves clinical outcomes, particularly in BRCA1/2-mutant and HRR-deficient mCRPC patients.

PARP inhibitors as therapy for small cell lung carcinoma: A systematic review and meta-analysis of clinical trials

BACKGROUND

Small Cell Lung Cancer (SCLC) is a neuroendocrine carcinoma characterized by aggressive behavior and poor prognosis with limited treatment options. Poly ADP-Ribose Polymerase inhibitors (PARPi) are novel anti-cancer agents that induce DNA damages and cause cell death in tumor cells with impaired DNA repair, known as the synthetic lethality concept. This study aimed to analyze the efficacy and safety of PARPi for patients with SCLC from available clinical trial data.

METHODS

Studies reporting efficacy and safety of PARPi therapy for SCLC patients were searched across five databases with predetermined eligibility criteria in accordance with the PRISMA statement. Critical appraisal was done using suitable tools, outcomes were extracted, and analyzed.

RESULTS

Five randomized controlled clinical trials with 451 interventional patients and 308 control patients with SCLC were included. The analysis showed increased Progression-Free Survival (PFS) (RR 0.92 (95 %CI 0.84-1.00; p=0.05)) and Objective Response Rate (ORR) (RR 1.27 (95 %CI 1.07-1.50; p=0.007)), no significant difference in Overall Survival (OS) (RR 1.03 (95 %CI 0.92-1.15; p=0.60)), and an increased risk for serious Treatment Emergent Adverse Events (TEAEs) (RR 1.13 (95 %CI 0.95-1.35; p=0.16)) in PARPi-receiving SCLC patients. Amongst the hematologic toxicities, sub-analysis showed that thrombocytopenia had the highest risk, followed by neutropenia, anemia, leukopenia, and lymphopenia.

CONCLUSION

The addition of PARPi in the chemotherapy regimen for patients with SCLC results in increased PFS and ORR, with no difference in OS and an increased risk of TEAEs. Further and larger clinical studies are needed to validate the efficacy and safety of PARPi therapy for SCLC patients.

Circulating Biomarkers Predictive of Treatment Response in Patients with Hormone-sensitive or Castration-resistant Metastatic Prostate Cancer: A Systematic Review

BACKGROUND AND OBJECTIVE

Metastatic prostate cancer (mPCa) harbors genomic alterations that may predict targeted therapy efficacy. These alterations can be identified not only in tissue but also directly in biologic fluids (ie, liquid biopsies), mainly blood. Liquid biopsies may represent a safer and less invasive alternative for monitoring patients treated for mPCa. Current research focuses on the description and validation of novel predictive biomarkers to improve precision medicine in mPCa. Our aim was to systematically review the current evidence on liquid biopsy biomarkers for predicting treatment response in mPCa.

METHODS

We systematically searched Medline, Web of Science, and evidence-based websites for publications on circulating biomarkers in mPCa between March 2013 and February 2024 for review. Endpoints were: prediction of overall survival, biochemical or radiographic progression-free survival after treatment (chemotherapy, androgen deprivation therapy, androgen receptor pathway inhibitors [ARPIs], immunotherapy, or PARP inhibitors [PARPIs]). For each biomarker, the level of evidence (LOE) for clinical validity was attributed: LOE IA and IB, high level of evidence; LOE IIB and IIC, intermediate level; and LOE IIIC and LOE IV-VD, weak level.

KEY FINDINGS AND LIMITATIONS

The predictive value of each biomarker for the response to several therapies was evaluated in both metastatic hormone-sensitive (mHSPC) and castration-resistant prostate cancer (mCRPC). In patients with mCRPC, BRCA1/2 or ATM mutations predicted response to ARPIs (LOE IB) and PARPIs (LOE IIB), while AR-V7 transcripts or AR-V7 protein levels in circulating tumor cells (CTCs) predicted response to ARPIs and taxanes (LOE IB). CTC quantification predicted response to cabazitaxel, abiraterone, and radium-223 (LOE IIB), while TP53 alterations predicted response to 177Lu prostate-specific membrane antigen radioligand treatment (LOE IIB). AR copy number in circulating tumor DNA before the first treatment line and before subsequent lines predicted response to docetaxel, cabazitaxel, and ARPIs (LOE IIB). In mHSPC, DNA damage in lymphocytes was predictive of the response to radium-223 (LOE IIB).

CONCLUSIONS AND CLINICAL IMPLICATIONS

BRCA1/2, ATM, and AR alterations detected in liquid biopsies may help clinicians in management of patients with mPCa. The other circulating biomarkers did not reach the LOE required for routine clinical use and should be validated in prospective independent studies.

PATIENT SUMMARY

We reviewed studies assessing the value of biomarkers in blood or urine for management of metastatic prostate cancer. The evidence indicates that some biomarkers could help in selecting patients eligible for specific treatments.

Efficacy and Safety of BRCA-targeted Therapy (Polyadenosine Diphosphate-ribose Polymerase Inhibitors) in Treatment of BRCA-mutated Breast Cancer: A Systematic Review and Meta-analysis

Breast cancer is the second leading cause of women's cancer deaths after lung cancer. Risk factors such as environment, lifestyle, and genetics contribute to its development, including mutation in the breast cancer (BRCA) gene. Polyadenosine diphosphate-ribose polymerase inhibitors (PARPi) target these mutations, benefiting patients with advanced cancers. This review summarizes PARPi' safety and efficacy in the treatment of BRCA-mutated breast cancer. PubMed, The Cochrane Library for Clinical Trials, and Science Direct, were searched for articles from inception to April 2024. Eligible articles were analyzed, and data were extracted for meta-analysis using RevMan 5.4 software with a random-effect model. Out of 430 articles identified from online databases, only 6 randomized control trials including 3610 patients were included in the analysis. PARPi therapy improved progression-free survival (hazard ratio: 0.64; 95% CI: 0.56, 0.73; P < 0.00001) and overall survival (hazard ratio: 0.84; 95% CI: 0.73, 0.98 P = 0.02), according to the analysis. In our safety analysis, the risk of adverse events was not statistically different between PARPi versus chemotherapy (relative risk [RR]: 1.08; 95% CI: 0.44, 2.68; P = 0.86), and combined PARPi and standard chemotherapy (RR: 1.00; 95% CI: 0.93, 1.07; P = 0.80). The only statistically significant difference was observed in anemia, where PARPi increased the risk of developing anemia compared with standard chemotherapy (RR: 6.17; 95% CI: 2.44, 15.58; P = 0.0001). In BRCA-mutated breast cancer, PARPi treatment shows better overall survival and progression-free survival compared with standard chemotherapy or placebo. Furthermore, PARPi, either alone or in combination therapy, does not increase the risk of adverse events in these patients, as per the meta-analysis.

Comparative effectiveness of first-line systemic treatments for metastatic castration-resistant prostate cancer: a systematic review and network meta-analysis

OBJECTIVES

No head-to-head trials had been performed to estimate the relative effectiveness of poly ADP-ribose polymerase inhibitor (PARPi) and androgen receptor signaling inhibitor (ARSi) in the first-line treatment for metastatic castration-resistant prostate cancer (mCRPC). We aimed to perform a systematic review and network meta-analysis to evaluate the comparative effectiveness of various systemic treatment agents for patients with mCRPC.

METHODS

A comprehensive literature search was conducted for abstracts and full-text articles from the database's inception through April 27, 2023. The study concentrated on assessing radiographic progression-free survival (rPFS) for both overall and homologous recombination repair mutation (HRRm) population, with overall survival (OS) as the secondary measure. Under the Bayesian framework, the overall effect was pooled using the fixed-effects model in base case analysis. Scenario analysis using restricted mean survival time (RMST) methods was performed to test the robustness of the results.

RESULTS

Nine studies with 6,830 patients and 8 unique treatment options were included. Network meta-analysis demonstrated that talazoparib in combination with enzalutamide (TALA + ENZA; overall population, hazard ratio [HR], 0.20; 95% credible interval [CrI]: 0.16-0.26; RMST, 3.51; 95% confidence interval [CI] 2.46-4.60; HRRm population, HR, 0.15; 95% CrI: 0.09-0.23; RMST, 4.14; 95% CI 2.84-5.39) was superior to other treatments in the first-line setting in terms of rPFS. The results of Bayesian framework and RMST models showed consistent efficacy ranks. When extrapolated to overall survival benefit, within the Bayesian framework, olaparib plus abiraterone acetate and prednisone (OLAP + AAP) achieved the highest OS benefit for the overall population, which was not statistically significant when compared to TALA + ENZA. However, TALA + ENZA achieved the highest OS benefit at 3 years by applying RMST.

CONCLUSIONS

We suggest that talazoparib in combination with enzalutamide is probably a preferred treatment agent for the overall population and HRRm patients with mCRPC. Given the limitations of network framework and the modeling assumptions undertaken to finalize the analyses, results should be cautiously interpreted.

To Establish a Nomogram Prediction of Prostate Cancer Based on Pyroptosis-Related Genes that Affect the Immune Microenvironment

BACKGROUND

Prostate cancer is the most common tumor in men worldwide with a poor prognosis. In recent years, studies have revealed that pyroptosis can affect the tumor immune microenvironment. However, the relationship between the immune microenvironment regulated by pyroptosis-related genes and the prognosis of prostate cancer is still unclear.

METHODS

Thirty-three cell death-associated genes were selected from a literature review. The "DESeq2" R package was used to identify differentially expressed cell death-associated genes between normal prostate tissue (GTEx) and prostate cancer tissue (TCGA) samples. Biological functional enrichment analysis of differentially expressed cell death genes was performed using R statistical software packages, such as "clusterProfiler," "org.Hs.eg.db," "enrichplot," "ggplot2," and "GOplot." Univariate Cox and LASSO Cox regression analyses were conducted to identify prognostic genes associated with the immune microenvironment using the "survival" package. Finally, a predictive model was established based on Gleason score, T stage, and cell death-associated genes.odel was established based on Gleason score, T stage, and cell death-associated genes.

RESULTS

Seventeen differentially expressed genes related to pyroptosis were screened out. Based on these differentially expressed genes, biological function enrichment analysis showed that they were related to pyroptosis of prostate cells. Based on univariate Cox and (LASSO) Cox regression analysis, four pyroptosis-related genes (CASP3, PLCG1, GSDMB, GPX4) were determined to be related to the prognosis of prostate cancer, and the immune correlation analysis of the four pyroptosis-related genes was performed. The expression of CASP3, PLCG1 and GSDMB was positively correlated with the proportion of immune cells, and the expression of GPX4 was negatively correlated with the proportion of immune cells. A predictive nomogram was established by combining Gleason score, T and pyroptosis genes. The nomogram was accompanied by a calibration curve and used to predict 1 -, 2 -, and 5-year survival in PAAD patients.

CONCLUSION

Cell death-associated genes (CASP3, PLCG1, GSDMB, GPX4) play crucial roles in modulating the immune microenvironment and can be used to predict the prognosis of prostate cancer.

Personalized Medicine in Pancreatic Cancer: The Promise of Biomarkers and Molecular Targeting with Dr. Michael J. Pishvaian

Pancreatic cancer, with its alarming rising incidence, is predicted to become the second deadliest type of solid tumor by 2040, highlighting the urgent need for improved diagnostic and treatment strategies. Despite medical advancements, the five-year survival rate for pancreatic cancer remains about 14%, dropping further when metastasized. This review explores the promise of biomarkers for early detection, personalized treatment, and disease monitoring. Molecular classification of pancreatic cancer into subtypes based on genetic mutations, gene expression, and protein markers guides treatment decisions, potentially improving outcomes. A plethora of clinical trials investigating different strategies are currently ongoing. Targeted therapies, among which those against CLAUDIN 18.2 and inhibitors of Claudin 18.1, have shown promise. Next-generation sequencing (NGS) has emerged as a powerful tool for the comprehensive genomic analysis of pancreatic tumors, revealing unique genetic alterations that drive cancer progression. This allows oncologists to tailor therapies to target specific molecular abnormalities. However, challenges remain, including limited awareness and uptake of biomarker-guided therapies. Continued research into the molecular mechanisms of pancreatic cancer is essential for developing more effective treatments and improving patient survival rates.

The efficacy and safety of PARP inhibitors in mCRPC with HRR mutation in second-line treatment: a systematic review and bayesian network meta-analysis

BACKGROUND

Poly (ADP- ribose) polymerase inhibitors (PARPi) has been increasingly adopted for metastatic castration-resistance prostate cancer (mCRPC) patients with homologous recombination repair deficiency (HRD). However, it is unclear which PARPi is optimal in mCRPC patients with HRD in 2nd -line setting.

METHOD

We conducted a systematic review of trials regarding PARPi- based therapies on mCRPC in 2nd -line setting and performed a Bayesian network meta-analysis (NMA). Radiographic progression-free survival (rPFS) was assessed as primary outcome. PSA response and adverse events (AEs) were evaluated as secondary outcomes. Subgroup analyses were performed according to specific genetic mutation.

RESULTS

Four RCTs comprised of 1024 patients (763 harbored homologous recombination repair (HRR) mutations) were identified for quantitative analysis. Regarding rPFS, olaparib monotherapy, rucaparib and cediranib plus olaparib showed significant improvement compared with ARAT. Olaparib plus cediranib had the highest surface under cumulative ranking curve (SUCRA) scores (87.5%) for rPFS, followed by rucaparib, olaparib and olaparib plus abiraterone acetate prednisone. For patients with BRCA 1/2 mutations, olaparib associated with the highest probability (98.1%) of improved rPFS. For patients with BRCA-2 mutations, olaparib and olaparib plus cediranib had similar efficacy. However, neither olaparib nor rucaparib showed significant superior effectiveness to androgen receptor-axis-targeted therapy (ARAT) in patients with ATM mutations. For safety, olaparib showed significantly lower ≥ 3 AE rate compared with cediranib plus olaparib (RR: 0.72, 95% CI: 0.51, 0.97), while olaparib plus cediranib was associated with the highest risk of all-grade AE.

CONCLUSION

PARPi-based therapy showed considerable efficacy for mCRPC patients with HRD in 2nd -line setting. However, patients should be treated accordingly based on their genetic background as well as the efficacy and safety of the selected regimen.

TRIAL REGISTRATION

CRD42023454079.

Contemporary Diagnostic Reporting for Prostatic Adenocarcinoma: Morphologic Aspects, Molecular Correlates, and Management Perspectives

The diagnosis and reporting of prostatic adenocarcinoma have evolved from the classic framework promulgated by Dr Donald Gleason in the 1960s into a complex and nuanced system of grading and reporting that nonetheless retains the essence of his remarkable observations. The criteria for the "Gleason patterns" originally proposed have been continually refined by consensuses in the field, and Gleason scores have been stratified into a patient-friendly set of prognostically validated and widely adopted Grade Groups. One product of this successful grading approach has been the opportunity for pathologists to report diagnoses that signal carefully personalized management, placing the surgical pathologist's interpretation at the center of patient care. At one end of the continuum of disease aggressiveness, personalized diagnostic care means to sub-stratify patients with more indolent disease for active surveillance, while at the other end of the continuum, reporting histologic markers signaling aggression allows sub-stratification of clinically significant disease. Whether contemporary reporting parameters represent deeper nuances of more established ones (eg, new criteria and/or quantitation of Gleason patterns 4 and 5) or represent additional features reported alongside grade (intraductal carcinoma, cribriform patterns of carcinoma), assessment and grading have become more complex and demanding. Herein, we explore these newer reporting parameters, highlighting the state of knowledge regarding morphologic, molecular, and management aspects. Emphasis is made on the increasing value and stakes of histopathologists' interpretations and reporting into current clinical risk stratification and treatment guidelines.

Survival after docetaxel for metastatic castration-resistant prostate cancer in a rural health care setting

Introduction

The aim of this study was to evaluate overall survival of men who received systemic therapy with docetaxel for metastatic castration- resistant prostate cancer (MCRPC) in rural Nordland County, Norway. Prognostic factors related to treatment and other variables were evaluated.

Material and methods

Overall, 132 pa- tients were included in this retrospective study covering the years 2009-2022. Uni- and multivariate survival analyses were performed.

Results

In this elderly cohort (median age 72 years), weekly low-dose docetaxel was the preferred regimen (44%). Seventy-three percent were treated in the first line. Only 11 patients (8%) were pre-exposed to docetaxel in the hormone-sensitive phase. Median survival was 14.3 months. Prognostic factors for longer survival included higher hemoglobin, lower lactate dehydrogenase, administration of docetaxel as first-line MCRPC treatment, and use of fewer prescription drugs for comorbidity. Pre-exposure to docetaxel did not play a major role, p = 0.76.

Conclusions

In this rural health care setting, survival after docetaxel was shorter than reported by other groups. Blood test results were confirmed as important prognostic factors. In the present era of evolving treatment sequences, we recommend monitoring of real-world treatment results.

Exploiting the DNA Damage Response for Prostate Cancer Therapy

Prostate cancers that progress despite androgen deprivation develop into castration-resistant prostate cancer, a fatal disease with few treatment options. In this review, we discuss the current understanding of prostate cancer subtypes and alterations in the DNA damage response (DDR) that can predispose to the development of prostate cancer and affect its progression. We identify barriers to conventional treatments, such as radiotherapy, and discuss the development of new therapies, many of which target the DDR or take advantage of recurring genetic alterations in the DDR. We place this in the context of advances in understanding the genetic variation and immune landscape of CRPC that could help guide their use in future treatment strategies. Finally, we discuss several new and emerging agents that may advance the treatment of lethal disease, highlighting selected clinical trials.

A Meta-Analysis of Randomized Clinical Trials Assessing the Efficacy of PARP Inhibitors in Metastatic Castration-Resistant Prostate Cancer

Prostate cancer ranks as the second most common malignancy in males. Prostate cancer progressing on androgen deprivation therapy (ADT) is castration-resistant prostate cancer (CRPC). Poly-ADP ribose polymerase (PARP) inhibitors (PARPis) have been at the forefront of the treatment of CRPC. We aim to better characterize the progression-free survival (PFS) and overall survival (OS) in metastatic CRPC patients treated with PARPis. A systemic review search was conducted using National Clinical Trial (NCT), PubMed, Embase, Scopus, and Central Cochrane Registry. The improvement in overall survival was statistically significant, favoring PARPis (hazard ratio (HR) 0.855; 95% confidence interval (CI) 0.752-0.974; p = 0.018). The improvement in progression-free survival was also statistically significant, with results favoring PARPis (HR 0.626; 95%CI 0.566-0.692; p = 0.000). In a subgroup analysis, similar results were observed where the efficacy of PARPis was evaluated in a subgroup of patients without homologous recombination repair (HRR) gene mutation, which showed improvement in PFS favoring PARPis (HR 0.747; 95%CI 0.0.637-0.877; p = 0.000). Our meta-analysis of seven RCTs showed that PARPis significantly increased PFS and OS when used with or without antihormonal agents like abiraterone or enzalutamide.

Castration-Resistant Prostate Cancer: From Uncovered Resistance Mechanisms to Current Treatments

Prostate cancer (PC) is the second most common cancer in men worldwide. Despite recent advances in diagnosis and treatment, castration-resistant prostate cancer (CRPC) remains a significant medical challenge. Prostate cancer cells can develop mechanisms to resist androgen deprivation therapy, such as AR overexpression, AR mutations, alterations in AR coregulators, increased steroidogenic signaling pathways, outlaw pathways, and bypass pathways. Various treatment options for CRPC exist, including androgen deprivation therapy, chemotherapy, immunotherapy, localized or systemic therapeutic radiation, and PARP inhibitors. However, more research is needed to combat CRPC effectively. Further investigation into the underlying mechanisms of the disease and the development of new therapeutic strategies will be crucial in improving patient outcomes. The present work summarizes the current knowledge regarding the underlying mechanisms that promote CRPC, including both AR-dependent and independent pathways. Additionally, we provide an overview of the currently approved therapeutic options for CRPC, with special emphasis on chemotherapy, radiation therapy, immunotherapy, PARP inhibitors, and potential combination strategies.