Comparison of Systemic Treatments for Metastatic Castration-Resistant Prostate Cancer After Docetaxel Failure: A Systematic Review and Network Meta-analysis

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.

Cancer associated fibroblast secreted miR-432-5p targets CHAC1 to inhibit ferroptosis and promote acquired chemoresistance in prostate cancer

Prostate cancer (PCa) ranks as the sixth most serious male malignant disease globally. While docetaxel (DTX) chemotherapy is the standard treatment for advanced PCa patients with distant metastasis, some individuals exhibit insensitivity or resistance to DTX. Cancer-associated fibroblasts (CAFs) play a pivotal role as stromal cells within the tumor microenvironment, influencing tumor development, progression, and drug resistance through exosomes. Ferroptosis, a novel form of programmed cell death, is characterized by intracellular iron accumulation that triggers lipid peroxidation, ultimately leading to cell demise. To delve into the potential mechanisms of chemotherapy resistance in prostate cancer, our research delved into the impact of CAF-derived exosomes on ferroptosis. Our findings revealed that CAF exosomes hindered the buildup of lipid reactive oxygen species (ROS) in prostate cancer cells induced by erastin, as well as mitigated erastin-induced mitochondrial damage, thereby impeding iron-induced cell death in prostate cancer cells. Furthermore, miR-432-5p was identified to diminish glutathione (GSH) consumption by targeting CHAC1, consequently inhibiting ferroptosis in prostate cancer cells. Our study found that miR-432-5p, originating from cancer-associated fibroblast (CAF) exosomes, suppresses ferroptosis by targeting CHAC1, thereby increasing resistance to docetaxel (DTX) in PCa. This research introduces a novel approach to address resistance to DTX.

Targeted Inhibition of CYP11A1 in Castration-Resistant Prostate Cancer

BACKGROUND: Prostate cancer is regulated by steroid hormones, even in castration-resistant disease. ODM-208, a novel inhibitor of cytochrome P450 11A1 (which catalyzes the first step of steroid-hormone biosynthesis), was investigated in patients with heavily pretreated metastatic castration-resistant prostate cancer (mCRPC). METHODS: CYPIDES is a first-in-human phase 1 (3 + 3 design) and phase 2 study. We administered ODM-208 twice daily with glucocorticoid/mineralocorticoid replacement and ongoing androgen deprivation therapy to adults with previously treated mCRPC, regardless of androgen receptor gene (AR) ligand-binding domain mutations (phase 1) and with activating AR ligand-binding domain mutations (ARmut; phase 2). Safety, pharmacokinetics, steroid-hormone pharmacodynamics, and preliminary efficacy were the key outcomes. RESULTS: Ninety-two patients received one or more doses of ODM-208: 47 in phase 1 (20 [42.6%] with ARmut) and 45 in phase 2 (all ARmut). A dose of ODM-208 of 5 mg twice a day with dexamethasone 1 mg/fludrocortisone 0.1 mg provided a balance between decreased steroidogenesis and toxicity. Treatment-related adrenal insufficiency was the most common toxicity in phase 1 (n=17, 36.2%; necessitating ODM-208 discontinuation in one patient); this toxicity occurred in six patients (13.3%) at 5 mg twice a day in phase 2. Median circulating testosterone levels declined from 3.0 ng/dl (interquartile range, 1.3 to 6.2 ng/dl) at baseline to undetectable levels within the first week of ODM-208 5 mg twice a day treatment in 46 of 53 (87%) patients. A decrease in prostate-specific antigen levels of 50% or more occurred in 14 of 19 (73.7%) patients with ARmut and 2 of 23 (8.7%) patients with AR wild type in phase 1 and in 24 of 45 (53.3%) patients with ARmut in phase 2. CONCLUSIONS: ODM-208 potently inhibited steroid-hormone biosynthesis with the expected toxicity of adrenal insufficiency. Evidence of antitumor activity was observed in this heavily pretreated mCRPC population, especially in those with ARmut. (Funded by Orion Pharma; ClinicalTrials.gov number, NCT03436485.)

Enzalutamide Prior to Radium-223 Is Associated with Better Overall Survival in Metastatic Castration-Resistant Prostate Cancer Patients Compared to Abiraterone-A Retrospective Study

Metastatic castration-resistant prostate cancer (mCRPC) is a progressive stage of prostate cancer that often spreads to the bone. Radium-223, a bone-targeting radiopharmaceutical, has been shown to improve the overall survival in mCRPC in patients without visceral metastasis. However, the impact of prior systemic therapy on the treatment outcome of mCRPC patients receiving radium-223 remains unclear. This study aimed to investigate the optimal choice of systemic therapy before radium-223 in mCRPC patients. The study included 41 mCRPC patients who received radium-223 therapy, with 22 receiving prior enzalutamide and 19 receiving prior abiraterone. The results showed that the median overall survival was significantly longer in the enzalutamide group than in the abiraterone group (25.1 months vs. 14.8 months, p = 0.049). Moreover, the number of patients requiring blood transfusion was higher in the abiraterone group than in the enzalutamide group (9.1% vs. 26.3%, p = 0.16). The study also found that the number of doses of Radium-223 received was significantly associated with overall survival (≥5 vs. <5, HR 0.028, 95%CI 0.003-0.231, p = 0.001). Our study provides insights into the optimal treatment choice for mCRPC prior to radium-223, indicating that enzalutamide prior to radium-223 administration may have better outcomes compared to abiraterone in mCRPC patients without visceral metastasis.

Pretreatment of prostate cancer cells with salinomycin and Wnt inhibitor increases the efficacy of cabazitaxel by inducing apoptosis and decreasing cancer stem cells

Cancer stem cells (CSCs) are associated with metastasis and recurrence in prostate cancer as well as other cancers. We aimed to enhance the sensitivity of cabazitaxel in prostate cancer cell therapy by targeting CSCs with a Wnt inhibitor and salinomycin pretreatment. PC3, DU-145, and LNCaP human prostate cancer cells were exposed to Wnt/β-catenin pathway inhibitor CCT036477 (iWnt) with salinomycin for 48 h, followed by cabazitaxel treatment for 48 h. Cell viability, mRNA, and protein expression changes were evaluated by MTT, RT-qPCR, and Western blot assays, respectively. Apoptosis was determined by image-based cytometry, and cell migration was assessed by wound healing assay. Three-dimensional culture was established to assess the malignant phenotype and stemness potential of transformed or cancer cells. CD44 + CSCs were isolated using magnetic-activated cell sorting system. Pretreatment of PC3, DU-145, and LNCaP cells with salinomycin iWnt significantly sensitized the cells to cabazitaxel therapy. Spheroid culture confirmed that the treatment modality was more effective than a single administration of chemotherapy. The pretreatment of PC3 cells increased the rate of apoptosis compared to single administration of cabazitaxel, which downregulated Bcl-2 and upregulated caspase 3, caspase 8 expressions. The pretreatment suppressed cell migration, downregulated the expression of Sox2 and Nanog, and significantly reduced CD44 + CSC numbers. Notably, the treatment modality reduced pAKT, p-P38 MAPK, and pERK1/2. The data suggest that pretreatment of prostate cancer cells with salinomycin and Wnt inhibitor may increase the efficacy of cabazitaxel therapy by inhibiting cell proliferation and migration, and eliminating cancer stem cells.

H3 histone methylation landscape in male urogenital cancers: from molecular mechanisms to epigenetic biomarkers and therapeutic targets

During the last decades, male urogenital cancers (including prostate, renal, bladder and testicular cancers) have become one of the most frequently encountered malignancies affecting all ages. While their great variety has promoted the development of various diagnosis, treatment and monitoring strategies, some aspects such as the common involvement of epigenetic mechanisms are still not elucidated. Epigenetic processes have come into the spotlight in the past years as important players in the initiation and progression of tumors, leading to a plethora of studies highlighting their potential as biomarkers for diagnosis, staging, prognosis, and even as therapeutic targets. Thus, fostering research on the various epigenetic mechanisms and their roles in cancer remains a priority for the scientific community. This review focuses on one of the main epigenetic mechanisms, namely, the methylation of the histone H3 at various sites and its involvement in male urogenital cancers. This histone modification presents a great interest due to its modulatory effect on gene expression, leading either to activation (e.g., H3K4me3, H3K36me3) or repression (e.g., H3K27me3, H3K9me3). In the last few years, growing evidence has demonstrated the aberrant expression of enzymes that methylate/demethylate histone H3 in cancer and inflammatory diseases, that might contribute to the initiation and progression of such disorders. We highlight how these particular epigenetic modifications are emerging as potential diagnostic and prognostic biomarkers or targets for the treatment of urogenital cancers.

Comparison of doublet and triplet therapies for metastatic hormone-sensitive prostate cancer: A systematic review and network meta-analysis

Background

The best choice of first-line treatment for metastatic hormone-sensitive prostate cancer (mHSPC) is unclear. We aimed to compare the effectiveness and safety determined in randomized clinical trials of doublet and triplet treatments for mHSPC.

Methods

Medline, Embase, Cochrane Central and ClinicalTrials.gov were searched from inception through July 01, 2022. Eligible studies were phase III randomized clinical trials evaluating androgen deprivation treatment (ADT) alone, doublet therapies [ADT combined with docetaxel (DOC), novel hormonal agents (NHAs), or radiotherapy (RT)], or triplet therapies (NHA+DOC+ADT) as first-line treatments for mHSPC. Outcomes of interest included overall survival (OS), progression-free survival (PFS) and grades 3-5 adverse events (AEs). Subgroup analyses were performed based on tumor burden. The effects of competing treatments were assessed by Bayesian network meta-analysis using R software.

Results

Ten trials with 12,298 patients comparing nine treatments were included. Darolutamide (DARO) +DOC+ADT ranked best in terms of OS benefits (OR 0·52 [95% CI 0·39-0·70]), but its advantages were all statistically insignificant compared with other therapy options except for DOC+ADT (OR 0·68 [95% CI 0·53-0·88]) and RT+ADT (OR 0·57 [95% CI 0·40-0·80]). In terms of PFS, enzalutamide(ENZA)+DOC+ADT (OR 0·32 [95% CI 0·24-0·44]) and abiraterone and prednisone (AAP) +DOC+ADT (OR 0·33 [95% CI 0·25-0·45]) ranked best. For patients with high volume disease (HVD), low volume disease (LVD), and visceral metastases, the optimal therapies were AAP+DOC+ADT (OR 0·52 [95% CI 0·33-0·83]), apalutamide+ADT (OR 0·52 [95% CI 0·26-1·05]) and DARO+DOC+ADT (OR 0·42 [95% CI 0·13-1·34]), respectively. For safety, AAP+DOC+ADT (OR 3·56 [95% CI 1·51-8·43]) ranked worst with the highest risk of grade 3-5 AEs.

Conclusions

Triple therapies may further improve OS and PFS but may be associated with a decrease in safety. Triplet therapies could be suggested for HVD patients, while doublet combinations should still be preferred for LVD patients.

Systematic Review Registration

https://www.crd.york.ac.uk/PROSPEROFILES/303117_STRATEGY_20220202.pdf, identifier CRD4202303117.

Integrating transcriptomics and network analysis-based multiplexed drug repurposing to screen drug candidates for M2 macrophage-associated castration-resistant prostate cancer bone metastases

Metastatic castration-resistant prostate cancer (CRPC) has long been considered to be associated with patient mortality. Among metastatic organs, bone is the most common metastatic site, with more than 90% of advanced patients developing bone metastases (BMs) before 24 months of death. Although patients were recommended to use bone-targeted drugs represented by bisphosphonates to treat BMs of CRPC, there was no significant improvement in patient survival. In addition, the use of immunotherapy and androgen deprivation therapy is limited due to the immunosuppressed state and resistance to antiandrogen agents in patients with bone metastases. Therefore, it is still essential to develop a safe and effective therapeutic schedule for CRPC patients with BMs. To this end, we propose a multiplex drug repurposing scheme targeting differences in patient immune cell composition. The identified drug candidates were ranked from the perspective of M2 macrophages by integrating transcriptome and network-based analysis. Meanwhile, computational chemistry and clinical trials were used to generate a comprehensive drug candidate list for the BMs of CRPC by drug redundancy structure filtering. In addition to docetaxel, which has been approved for clinical trials, the list includes norethindrone, testosterone, menthol and foretinib. This study provides a new scheme for BMs of CRPC from the perspective of M2 macrophages. It is undeniable that this multiplex drug repurposing scheme specifically for immune cell-related bone metastases can be used for drug screening of any immune-related disease, helping clinicians find promising therapeutic schedules more quickly, and providing reference information for drug R&D and clinical trials.

Outcomes Following Abiraterone versus Enzalutamide for Prostate Cancer: A Scoping Review

Abiraterone acetate (AA) and enzalutamide (ENZ) are commonly used for metastatic prostate cancer. It is unclear how their outcomes and toxicities vary with patient-specific factors because clinical trials typically exclude patients with significant comorbidities. This study aims to fill this knowledge gap and facilitate informed treatment decision making. A registered protocol utilizing PRISMA scoping review methodology was utilized to identify real-world studies. Of 433 non-duplicated publications, 23 were selected by three independent reviewers. ENZ offered a faster and more frequent biochemical response (30-50% vs. 70-75%), slowed progression (HR 0.66; 95% CI 0.50-0.88), and improved overall survival versus AA. ENZ was associated with more fatigue and neurological adverse effects. Conversely, AA increased risk of cardiovascular- (HR 1.82; 95% CI 1.09-3.05) and heart failure-related (HR 2.88; 95% CI 1.09-7.63) hospitalizations. Ultimately, AA was associated with increased length of hospital stay, emergency department visits, and hospitalizations (HR 1.26; 95% CI 1.04-1.53). Accordingly, total costs were higher for AA, although pharmacy costs alone were higher for ENZ. Existing data suggest that AA and ENZ have important differences in outcomes including toxicities, response, disease progression, and survival. Additionally, adherence, healthcare utilization, and costs differ. Further investigation is warranted to inform treatment decisions which optimize patient outcomes.