Treatment Of Metastatic Prostate Cancer Research Articles

Talazoparib plus enzalutamide versus olaparib plus abiraterone acetate and niraparib plus abiraterone acetate for metastatic castration-resistant prostate cancer: a matching-adjusted indirect comparison.

Without head-to-head trials between talazoparib+enzalutamide (TALA + ENZA), olaparib+abiraterone acetate (OLAP + AAP), and niraparib plus AAP (NIRA + AAP) the ability to evaluate their relative efficacy as first-line (1 L) treatment in metastatic castration-resistant prostate cancer (mCRPC) is limited. The objective of this study was to assess the relative efficacy between TALA + ENZA (TALAPRO-2) versus OLAP + AAP (PROpel) and NIRA + AAP (MAGNITUDE) in 1 L mCRPC via a matching-adjusted indirect treatment comparison (MAIC). Patient-level data from TALAPRO-2 and published data from PROpel and MAGNITUDE were used. TALAPRO-2 data were reweighted to satisfy the eligibility criteria for PROpel and MAGNITUDE. Talazoparib (0.5 mg/day) plus enzalutamide (160 mg/day) was compared to olaparib (300 mg twice daily) plus abiraterone acetate (1000 mg/day) and niraparib (200 mg/day) plus abiraterone acetate (1000 mg/day). Hazard ratios (HRs) were calculated for radiographic progression-free survival (rPFS) and overall survival (OS), and odds ratios (ORs) for prostate-specific antigen (PSA) response and objective response rate (ORR). Additional efficacy outcomes were assessed. In all-comers, TALA + ENZA was statistically superior to OLAP + AAP for rPFS (HR: 0.727; 95% confidence interval [CI]: 0.565, 0.935) and PSA response (OR: 1.663; 1.101, 2.510), and numerically favored for OS (HR: 0.847; 0.667, 1.076) and ORR (OR: 1.109; 0.646, 1.903). In patients with homologous recombination repair mutations (HRRm), relative to NIRA + AAP, TALA + ENZA was statistically superior for rPFS (HR: 0.460; 0.280, 0.754), and numerically favored for OS (HR: 0.601; 0.347, 1.041) and ORR (OR: 1.524; 0.579, 4.016). Results suggest that TALA + ENZA may provide improvements in clinical outcomes relative to OLAP + AAP and NIRA + AAP in 1 L mCRPC; however, inherent limitations associated with the complexity of the analyses must be considered.

Formulating abiraterone acetate-HPMCAS-based amorphous solid dispersions: insights into in vitro and biorelevant dissolution assessments and pharmacokinetic evaluations.

Abiraterone acetate (ABTA) is used as a primary treatment for metastatic castration-resistant prostate cancer. Its low aqueous solubility results in inadequate dissolution and poor oral bioavailability (<10%), necessitating the consumption of large doses of ABTA (1000 mg per day) for desired efficacy. The aim of this study is to enhance the solubility, dissolution, and bioavailability of ABTA through amorphous solid dispersions (SDs). ABTA-SD was prepared via a solvent granulation method with different grades of hydroxypropyl methylcellulose acetate succinate (HPMCAS 716 and 912). The theoretical solubility parameter between ABTA and HPMCAS was below 7 MPa1/2, indicating miscibility between the drug and the polymer according to the Hansen solubility parameter. HPMCAS showed a remarkable recrystallization inhibition of up to 180 min compared to the free drug (10 min), maintaining the soluble drug in supersaturation state and exhibiting the "spring and parachute" phenomenon. ABTA-SD exhibited a higher solubility (1.16-fold to 52-fold) in different media than free ABTA. The results of DSC, PXRD, ATR-FTIR, and FE-SEM indicated that the crystallinity of ABTA was completely transformed to an amorphous form and maintained in the SD formulation. In vitro and bio-relevant dissolution behavior of ABTA was studied in various dissolution media, indicating the higher dissolution of ABTA-SD than that of free ABTA. The pharmacokinetic study conducted in Wistar rats revealed that C max and AUC0-t of the optimized ABTA-SD formulation were significantly enhanced by 1.92-fold and 2.87-fold, respectively, compared to those of free ABTA.

Are Nanostructured Lipid Carriers (NLC) better than Solid Lipid Nanoparticles (SLN) for delivering abiraterone acetate through the gastrointestinal tract?

Abiraterone acetate (AbA) is a progesterone derivative indicated for the treatment of metastatic prostate cancer. This BCS (Biopharmaceutics Classification System) Class IV molecule has an extremely poor oral bioavailability (<10 %), notably due to its very low water solubility and intestinal permeability. Among the few existing galenic strategies to improve AbA’s oral bioavailability, lipid nanoparticles such as Solid Lipid Nanoparticles (SLN) and Nanostructured Lipid Carriers (NLC) are relevant nanovectors. The objective of this study is to develop and compare SLN and NLC for oral delivery of abiraterone acetate. Both SLN and NLC are biocompatible, biodegradable and produced by high pressure homogenization (HPH), an ecological-friendly manufacturing process, organic solvent-free and easily scalable. The HPH process allowed the formation of AbA-loaded SLN and NLC with particle size lower than 160 nm and high encapsulation efficiencies. The addition of a liquid lipid significantly reduced the mean diameter of the nanoparticles, reflecting the greater benefit of the NLC formulation compared to SLN. Both SLN and NLC formulations offered an important protection of AbA in intestinal media, with a better stability for NLC. When encapsulated in SLN or NLC, the AbA is strongly retained by the nanoparticles, whatever the dissolution medium, which means that both formulas are able to protect and retain the drug in the intestinal tract, right up to its delivery to the enterocytes surface. High concentrations of nanoparticles were administered without cytotoxicity, especially for the NLC, which provides a real added value in terms of biocompatibility with Caco-2 cells. Finally, the nanoparticles were able to penetrate into enterocytes by the transcellular route, demonstrating an intense cellular internalization.

Apalutamide in Metastatic Castration-sensitive Prostate Cancer: Results from the Multicenter Real-world ARON-3 Study

Background and objectiveApalutamide (APA) is a treatment for metastatic castration-sensitive prostate cancer (mCSPC). In the ARON-3 study we investigated real-world experiences with APA treatment for mCSPC. MethodsWe retrospectively assessed real-world clinical outcomes for patients with mCSPC treated with APA in the ARON-3 study. Overall survival (OS) was calculated from APA initiation to death from any cause. PSA90 was defined as a prostate-specific antigen decline of ≥90% from baseline, and PSA0.2 as achievement of a PSA level ≤0.2 ng/ml. Data for adverse events were retrospectively collected from electronic and paper charts and categorized according to Common Terminology Criteria for Adverse Events v5.0. Key findings and limitationsWe included 531 patients with mCSPC treated with APA. High-volume disease was reported for 214 patients (40%), and 56 (11%) had visceral metastases. Median OS was not reached. PSA90 was experienced by 461 patients (87%) and PSA0.2 by 368 (69%). Median OS was significantly longer for patients with PSA90 or PSA0.2 than for subjects without these responses (p < 0.001). The incidence of grade 3–4 fatigue was higher among elderly patients (≥80 yr) than among younger patients (19% vs 5%), but the incidence of other adverse events was comparable between the age groups. Conclusions and clinical implicationsAPA is an effective and tolerable treatment for mCSPC in the real-world setting. Patient summaryThe ARON-3 project collects data for patients with prostate cancer treated in multiple centers worldwide to assess outcomes in the real-world setting. We analyzed data for patients with metastatic hormone-sensitive prostate cancer receiving apalutamide. Our results show that apalutamide is a safe and effective drug in the real-world setting as well as in clinical trials.

Talazoparib for the Treatment of Metastatic Castration-resistant Prostate Cancer

Breast and prostate cancer are among the most commonly diagnosed cancers worldwide. Recent advances in tumor sequencing and gene studies have led to a paradigm shift from treatment centered on the type of tumor to therapy more focused on specific immune phenotype markers and molecular alterations. In this review, we discuss the utility and function of talazoparib concerning prostate cancer treatment and summarize recent and planned clinical trials on talazoparib. We searched medical databases for articles relating to the use of talazoparib in prostate cancer from inception. Poly ADP ribose polymerase (PARP) is a family of 17 necessary DNA repair enzymes responsible for base excision repair, single-strand break repair, and double-strand break repair. PARP inhibitors are a class of oral targeted therapies that compete for the NAD+ binding site on PARP molecules. Talazoparib, a potent PARP inhibitor, has emerged as a significant therapeutic option in the treatment of metastatic castration-resistant prostate cancer (mCRPC), particularly for patients with specific genetic alterations. Its role as a PARP inhibitor makes it a targeted therapy, focusing on cancer cells with DNA repair deficiencies. Talazoparib’s role as a biomarker-directed therapy in advanced prostate cancer has been increasingly recognized. The TALAPRO-1 demonstrated durable antitumor activity in mCRPC patients. TALAPRO-2 is a notable clinical trial, specifically examining the effectiveness of Talazoparib when used in combination therapies. Current investigations demonstrate a significant improvement in survival outcomes for the patients of mCRPC, making Talazoparib a promising intervention.

Prostate radiotherapy in the era of intensified systemic treatment of metastatic prostate cancer

Prostate radiotherapy in the era of intensified systemic treatment of metastatic prostate cancer

Osteoblast-Derived ECM1 Promotes Anti-Androgen Resistance in Bone Metastatic Prostate Cancer.

Acquired resistance to hormonal therapy, particularly enzalutamide (ENZ), remains a significant obstacle in the treatment of advanced bone metastatic prostate cancer. Here, it is demonstrated that under ENZ treatment, osteoblasts in the bone microenvironment secrete increased levels of extracellular matrix protein 1 (ECM1), which affects surrounding prostate cancer cells, promoting tumor cell proliferation and anti-androgen resistance. Mechanistically, ECM1 interacts with the enolase 1 (ENO1) receptor on the prostate cancer cell membrane, leading to its phosphorylation at the Y189 site. This event further recruits adapter proteins including growth factor receptor-bound protein 2 (GRB2) and son of sevenless homolog 1 (SOS1), which activates the downstream mitogen-activated protein kinase (MAPK) signaling pathway to induce anti-androgen resistance. Furthermore, inhibiting ECM1 or utilizing the ENO1-targeting inhibitor phosphonoacetohydroxamate (PhAH) significantly restores tumor cell sensitivity to ENZ. Taken together, a potential mechanism is identified through which osteoblast-derived ECM1 drives resistance in bone metastatic prostate cancer under ENZ treatment. Additionally, the findings indicate that ECM1 and ENO1 may serve as potential targets for developing therapies for bone metastatic castration-resistant prostate cancer.

Real-World Comparison of Cabazitaxel Versus 177Lu-PSMA Radiopharmaceutical Therapy in Metastatic Castration-Resistant Prostate Cancer.

177Lu-vipivotide tetraxetan prostate-specific membrane antigen (177Lu-PSMA) therapy is under current scientific investigation and aims to become established in the treatment of metastatic castration-resistant prostate cancer (mCRPC). However, real-world evidence in treatment comparison is scant. Methods: We relied on the FRAMCAP database and compared cabazitaxel versus 177Lu-PSMA therapy in mCRPC patients regarding progression-free survival (PFS) and overall survival (OS). Sensitivity analyses addressed second- to fourth-line mCRPC treatment to approximate current phase III patient selection criteria. Results: Of 373 patients, 14% received cabazitaxel, 65% received 177Lu-PSMA, and 21% received both. Patients undergoing 177Lu-PSMA therapy were significantly older than cabazitaxel patients (median, 72 y vs. 66 y; P < 0.01), and a higher proportion had an Eastern Cooperative Oncology Group score of 2 or more (12% vs. 5.0%, P = 0.1). Rates of a prostate-specific antigen decline of at least 50% were 32% versus 0% for 177Lu-PSMA versus cabazitaxel. In outcome analyses, significant superior median PFS was observed for 177Lu-PSMA versus cabazitaxel (13.4 mo vs. 7.1 mo, P < 0.001), even after multivariable adjustment (hazard ratio, 0.38; P < 0.001). Regarding OS, rates also significantly differed, with median OS of 14.7 mo versus 16.5 mo versus 29.6 mo for cabazitaxel versus 177Lu-PSMA versus both treatments (P < 0.01). In sensitivity analyses of second- to fourth-line mCRPC treatment, PFS rates and median OS rates for cabazitaxel versus 177Lu-PSMA versus both therapies qualitatively remained the same as for the entire cohort. Conclusion: In a real-world setting, 177Lu-PSMA provides significantly better PFS and qualitatively better OS rates than does cabazitaxel chemotherapy and should therefore be considered a valuable treatment option for advanced mCRPC patients according to the European Medicines Agency approval.

Abstract B042: Molecular assessment of cell surface targets using integrated circulating tumor cell (CTC) RNAseq and single CTC phenotyping

Abstract Background: Androgen-targeted therapies are a mainstay of treatment for metastatic prostate cancer and have significantly improved patient outcomes. However, development of treatment resistance remains universal, occurring through androgen receptor (AR) alterations driving constitutive AR signaling, or lineage state transitions that bypass AR entirely and culminate in a small cell/neuroendocrine phenotype (NEPC). Cell surface targeted therapies, including antibody drug conjugates and targeted radioligand therapies, represent a new therapeutic class that has shown promise for treatment of androgen-resistant metastatic prostate cancer (mCRPC). Circulating tumor cells (CTCs) present an accessible source of tumor material to identify expression of known and novel targets for therapeutic development, as well as the unique potential for longitudinal profiling to understand the evolution of target expression and association with clinical resistance to cell surface targeted therapies. We have developed a CTC platform allowing for gene expression and protein profiling of cell surface targets on CTCs. Methods: Live CTCs were isolated with our automated microfluidic technology integrating negative and positive selection for CTC enrichment with a cohort of 273 samples. CTCs were captured immunomagnetically followed by RNA isolation on chip and RNA-seq, or protein staining on chip for single cell fluorescent quantification of prostate adenocarcinoma and NEPC cell surface targets including PSMA, TROP2, B7H3 and DLL3. Results: CTC RNA sequencing can be used to understand the expression of cell surface targets across different CTC phenotypes. In CTCs from patient with mCRPC, canonical prostate adenocarcinoma cell surface targets STEAP1, KLK2 and FOLH1 and epithelial cell surface target TACSTD2 had the highest expression, while prostate adenocarcinoma target STEAP2, pan-tumor target ERBB2, and tumor immune checkpoint cell surface protein CD276 (B7H3) had intermediate expression. Expression of DLL3 and SSTR2, targets associated with neuroendocrine differentiation, was lowest, though still detected in a subset of CRPC CTCs. Comparison of expression levels between CRPC and NEPC CTCs demonstrated lower expression of most adenocarcinoma cell surface targets in NEPC CTCs as expected, and a trend towards higher expression of DLL3 and SSTR2. Cell surface expression is being assessed for proteins including Trop-2, PSMA and DLL3. Evaluation of DLL3 at the protein level in a subset of patients including both CRPC (n=13) and NEPC (n=12) confirmed that DLL3 was detected in both adenocarcinoma and neuroendocrine CTCs, with a median of 45.8% DLL3-positive CTCs per sample. Conclusions: Biomarkers are needed to better predict response and resistance to targeted therapies. CTC RNAseq and single CTC phenotyping hold potential for predictive and on-treatment biomarkers of response to cell surface targeted therapies. Further study of mechanisms driving response and resistance can be evaluated with these biomarkers. Citation Format: Jamie M. Sperger, Marina N. Sharifi, Katherine R. Kaufmann, Matthew L. Bootsma, Shannon R. Reese, Viridiana Carreno, Alex H. Chang, Luke A. Nunamaker A. Nunamaker, Charlotte Linebarger, Amy K. Taylor, Katherine E Tippins, Kyle T. Helzer, Shuang G. Zhao, Joshua M Lang. Molecular assessment of cell surface targets using integrated circulating tumor cell (CTC) RNAseq and single CTC phenotyping [abstract]. In: Proceedings of the AACR Special Conference: Liquid Biopsy: From Discovery to Clinical Implementation; 2024 Nov 13-16; San Diego, CA. Philadelphia (PA): AACR; Clin Cancer Res 2024;30(21_Suppl):Abstract nr B042.

Experience of rescue therapy with [177Lu]Lu-rhPSMA-10.1 in patients with primary or acquired resistance to [177Lu]Lu-PSMA-I&T.

Radioligand therapy is an increasingly important option for the treatment of metastatic castrate-resistant prostate cancer (mCRPC). Radiohybrid ligands targeting prostate-specific membrane antigen (PSMA) are a novel group of theranostic radioligand therapy agents for which higher tumour absorbed radiation doses have been demonstrated compared to established PSMA ligands. Here, we report data from ten patients who were treated within a compassionate use program with the radiohybrid PSMA-ligand [177Lu]Lu-rhPSMA-10.1 after experiencing disease progression under treatment with [177Lu]Lu-PSMA-I&T. Ten patients with advanced PSMA-positive prostate cancer who showed progression under treatment with [177Lu]Lu-PSMA-I&T received up to three cycles of rescue therapy with [177Lu]Lu-rhPSMA-10.1 (7.4-8.1 GBq per cycle). Efficacy (PSA response according to PCWG3 and RECIP) and overall survival were evaluated. Adverse events were recorded from first application. Despite progression with [177Lu]Lu-PSMA-I&T, after the first cycle of [177Lu]Lu-rhPSMA-10.1 rescue therapy, five patients (50%) showed a decrease in serum PSA level. In imaging, three of the ten patients (30%) showed a partial radiologic response. Four of the five patients with a decrease of serum PSA under [177Lu]Lu-rhPSMA-10.1 had initially responded to treatment with [177Lu]Lu-PSMA-I&T but had become resistant. However, the remaining patient had shown continuous disease progression during [177Lu]Lu-PSMA-I&T therapy but showed an immediate response to [177Lu]Lu-rhPSMA-10.1. The additional treatment with [177Lu]Lu-rhPSMA-10.1 was generally well tolerated by all patients. Patients showing tumour progression while receiving [177Lu]Lu-PSMA-I&T radioligand therapy may benefit from rescue therapy with the novel radiohybrid PSMA ligand, [177Lu]Lu-rhPSMA-10.1. Higher tumour absorbed radiation doses with [177Lu]Lu-rhPSMA-10.1 may overcome primary and acquired radiation resistance.

ASO Author Reflections: It Does Not Matter Whether Radical Prostatectomy is Performed in High-Risk Localized Disease or at the Oligometastatic Stage.

Radical prostatectomy (RP) alone has traditionally been considered insufficient for patients with high-risk localized prostate cancer (HRPC) owing to the frequent need for adjuvant salvage radiotherapy or androgen deprivation therapy (ADT) following surgery. Previously, systemic therapy, such as ADT, was the standard treatment for metastatic prostate cancer (PC) patients; RP was not considered viable for these patients. However, since 2015, there has been a recognition that metastatic PC patients can be categorized based on the extent of their metastases, leading to the consideration of RP for some metastatic cases. In recent years, the concept of cytoreductive RP has gained traction; studies suggest that it may improve survival rates in metastatic PC patients through mechanisms, such as tumor debulking and enhancement of the immune response. A meta-analysis of retrospective studies has shown that cytoreductive RP is associated with higher cancer-specific survival rates at 1-year, 3-year, and 5-year intervals compared with systemic therapy alone. In our study, which followed HRPC and oligometastatic PC patients for an average of 46 months, we observed biochemical recurrence in 17.8% of HRPC and 13% of oligometastatic patients, with overall survival rates of 96.4% and 87%, respectively. Although prospective or randomized studies are still lacking, current retrospective studies, including our own, suggest promising outcomes for RP in HRPC and oligometastatic patients. With the increasing prevalence of robotic surgery, improved pelvic anatomy observation, and growing surgical confidence, the realization of prospective randomized study results may not be far off.

Association of serum steroids with survival in metastatic hormone-sensitive prostate cancer.

The CHAARTED study showed that adding docetaxel (Doc) to androgen deprivation therapy (ADT) in men initiating treatment for metastatic hormone sensitive prostate cancer (mHSPC) prolongs survival, particularly in high-volume disease. Androgens drive both mHSPC and metastatic castration resistant prostate cancer (mCRPC). Lower nadir serum testosterone (T) concentrations are associated with better outcomes in men treated with ADT for biochemical relapse, while higher androgens at mCRPC are associated with better prognosis and increased benefit from abiraterone. We evaluated the association of serum steroids at 24 weeks with overall survival (OS) and time to CRPC (TTCRPC) in 588 men with available samples from the CHAARTED study. Steroid concentrations were measured using mass spectrometry. The median T concentration at 24 weeks was 8 ng/dl and did not differ in ADT alone vs ADT plus Doc arms. Achieving nadir T below 20ng/dl was not associated with OS or TTCRPC in either arm. In high volume disease, Doc conferred an OS and TTCRPC benefit regardless of steroid concentrations. In low volume disease, steroid concentrations in the lowest quartile at week 24 identified a subset of men with poor survival outcomes more like high volume disease, and in whom Doc was also associated with improved OS and TTCRPC. The known OS benefit of Doc in high volume mHSPC is not modified by serum steroid concentrations achieved on treatment. In low volume disease, steroid concentrations in the lowest quartile may identify a poor prognosis subset in whom Doc also confers OS benefit.

Investigating High-risk Factors, Precise Diagnosis, and Treatment of Castration- Resistant Prostate Cancer (CRPC).

The treatment of metastatic castration-resistant prostate cancer (mCRPC) in the actual world currently presents difficulties. In light of this, it is crucial to investigate high-risk factors for the progression of advanced prostate cancer and to identify methods for delaying the onset of CRPC. This study aimed to explore the high-risk factors that impact the progression of prostate cancer and emphasize the significance of precise diagnosis and treatment based on etiological classification in the clinical management of castration-resistant prostate cancer. A retrospective analysis was conducted on 277 newly diagnosed cases of PCa treated with endocrine therapy. A follow-up was done on prostate-specific antigen (PSA) levels and testosterone. Additionally, a prospective analysis was performed on the clinical data of 60 patients with CRPC. Following the principle of "4W1H", 30 patients were included in the precision treatment group for a second biopsy and related tests, while another 30 patients were included in the conventional treatment group. The therapeutic effect and prognosis of the two groups were observed. Distant metastasis (HR = 1.879, 95% CI: 1.311 ~ 2.694, P = 0.001), PSA nadir > 0.2 ng/mL (HR = 1.843, 95% CI: 1.338 ~ 2.540, P = 0.001), testosterone nadir > 20 ng/dL (HR = 1.403, 95% CI: 1.035 ~ 1.904, P = 0.029), and time to testosterone nadir > 6 months (HR = 1.919, 95% CI: 1.364 ~ 2.701, P = 0.001) were risk factors for the progression to CRPC. Patients in the CRPC group were treated with precision therapy and conventional therapy based on their molecular subtyping. The precision treatment group showed a significantly prolonged median PSA progression-free survival compared to the conventional treatment group (16.0 months vs. 13.0 months, P=0.025). The median radiographic progression-free survival was also significantly extended in the precision treatment group compared to the conventional treatment group (21.0 months vs. 16.0 months, P=0.042). Patients with prostate cancer diagnosed with distant metastasis at initial presentation require early intervention. Close monitoring of PSA and serum testosterone changes is necessary during the process of endocrine therapy. After entering the CRPC stage, the etiological classification precision treatment can improve the therapeutic effect and improve the prognosis of patients.

P117 Metastatic castration-sensitive prostate cancer treatment patterns by year: A realworld study in Europe

P117 Metastatic castration-sensitive prostate cancer treatment patterns by year: A realworld study in Europe

PARP inhibitors in prostate cancer: clinical applications.

Despite recent advancements in the treatment of metastatic castrate-resistant prostate cancer (mCRPC), this disease remains lethal. A novel family of targeted pharmaceuticals known as poly-ADP-ribose polymerase (PARP) inhibitors has been developed to treat mCRPC patients with homologous recombination repair (HRR) gene alterations. The FDA recently approved olaparib and rucaparib for treating mCRPC patients with HRR gene alterations. Ongoing trials are investigating combination therapies involving PARP inhibitors combined with radiation, chemotherapy, immunotherapy, and androgen receptor signaling inhibitors (ARSIs) to improve the effectiveness of PARP inhibitors and broaden the range of patients who can benefit from the treatment. This review provides an overview of the development of PARP inhibitors in prostate cancer and analyzes the mechanisms underlying their resistance.

Bone-Targeting Radionuclides in the Treatment of Metastatic Castration-Resistant Prostate Cancer: A Review on Radium-223 Chloride (Alpharadin) in Combination with Other Therapies.

Recent advances have broadened the range of therapeutic options for mCRPC, with several new treatments, including novel hormonal therapies (enzalutamide, abiraterone), chemotherapeutic agents (docetaxel, cabazitaxel), immunotherapies (sipuleucel-T), and bone targeting radiopharmaceuticals (radium-223) showing improved clinical outcomes and receiving U.S. Food and Drug Administration approval. These new treatments provide new avenues for improving patient survival and quality of life. Radium-223, a targeted alpha-emitter, specifically targets bone metastases, offering palliative benefits and a potential increase in life expectancy. The integration of radium-223 with other treatments shows promise for managing mCRPC. However, the optimal sequencing and combination of radium-223 with other therapies are still being explored, with various clinical trials investigating new therapeutic approaches. The integration of these therapies, especially to provide more effective, personalized treatment strategies, requires further investigation. A thorough literature review was conducted on current treatments for mCRPC, including chemotherapeutic agents, oral hormonal therapies targeting the androgen receptor axis, immunotherapies, and radium-223. Ongoing clinical trials investigating radium-233 in the context of other therapies for the treatment of mCRPC patients were also reviewed. Further studies should focus on determining the optimal sequencing and dosing and identifying biomarkers that predict treatment response to enhance outcomes of mCRPC patients. This review underlines the rational strategies of combining radium-223 with other therapies, investigating their impact on bone in terms of delaying skeletal-related events, and managing bone disease progression in mCRPC patients.

Assessing the predictive value of intraductal carcinoma of the prostate (IDC-P) in determining abiraterone efficacy for metastatic hormone-sensitive prostate cancer (mHSPC) patients.

This study explored the value of intraductal carcinoma of the prostate (IDC-P) in predicting the efficacy of abiraterone treatment in metastatic hormone-sensitive prostate cancer (mHSPC) patients. A retrospective study of 925 patients who underwent prostate biopsies to detect IDC-P was conducted, with participants divided into two cohorts. The first cohort of 165 mHSPC patients receiving abiraterone treatment was analyzed to compare therapeutic effectiveness between IDC-P positive and negative cases. Utilizing propensity score matching (PSM) to reduce bias, outcomes such as PSA response, progression-free survival (PSA-PFS), radiographic progression-free survival (rPFS), and overall survival were assessed. Additionally, the second cohort of 760 mHSPC patients compared the efficacy of abiraterone with conventional hormone therapy, focusing on differences between IDC-P positive and negative individuals. After PSM, our first cohort included 108 patients with similar baseline characteristics. Among them, 50% (54/108) were diagnosed with IDC-P, with 22.2% (12/54) having IDC-P pattern 1 and 77.8% (42/54) with IDC-P pattern 2. While no notable difference was seen in PSA responses between IDC-P positive and negative patients, IDC-P presence linked to worse clinical outcomes (PSA-PFS: 18.6 months vs. not reached [NR], p = 0.009; rPFS: 23.6 months vs. NR, p = 0.020). Further analysis showed comparable outcomes for IDC-P pattern 1 but significantly worse prognosis for IDC-P pattern 2 (PSA-PFS: 18.6 months vs. NR, p = 0.002; rPFS: 22.4 months vs. NR, p = 0.010). Subgroup analysis revealed IDC-P pattern 2 consistently predicted poorer outcomes across patient subgroups. Remarkably, both IDC-P positive and negative patients gained more from androgen deprivation therapy with abiraterone than conventional treatment, with IDC-P negative patients showing a more significant survival advantage, supported by better hazard ratios (0.47 and 0.66). This study found that IDC-P, especially pattern 2, predicts poor prognosis in mHSPC patients on abiraterone therapy. Also, abiraterone's advantage over hormone therapy is reduced in cases with IDC-P compared to those without.

The role of Cabazitaxel in Patients With Castration-Resistant and Osseous Metastases Prostate Cancer. A Hellenic Cooperative Oncology Group Phase II Study: Cabazitaxel in mCRPC patients with osseous metastases

BackgroundCabazitaxel is an effective treatment in metastatic castration-resistant prostate cancer (mCRPC) patients previously exposed to docetaxel and novel hormonal treatments. Understanding the molecular biology of mCRPC disease and taking into account the several approved treatment options, biomarkers are needed to guide decision making including cabazitaxel treatment. MethodsCababone was a phase II translational study that attempted to identify predictors of cabazitaxel efficacy. mCRPC with documented bone metastases were enrolled prospectively and treated with cabazitaxel 25mg/m2 every 3 weeks. Prostate cancer biopsies, bone marrow aspirates and blood samples were collected for translational research. ResultsSixty patients were enrolled and 59 received treatment according to protocol. Six-month progression free survival (PFS) rate was 47% (95% CI: 33% - 59%) and 12-month Overall Survival (OS) rate was 70% (95% CI: 56% - 80%). Patients with reactive hematopoiesis had improved PFS and OS with cabazitaxel treatment. Mutations in HRR genes were detected in 7 patients. ConclusionsNo differences in cabazitaxel efficacy were noted according to mutational status of HRR genes analyzed. No new safety issues were detected. In conclusion, CabaBone confirmed efficacy of cabazitaxel in mCRPC patients including the subgroup of patients with HRR mutations. Reactive hematopoiesis in bone marrow biopsies was related to improved survival warranting further investigation of bone biomarkers as predictors of cabazitaxel efficacy.

MSOR11 Presentation Time: 8:50 AM: Implementation and Its Experience of Open Radiopharmaceutical Source for Metastatic Prostate Cancer Treatment in Small Radiation Oncology Clinic

MSOR11 Presentation Time: 8:50 AM: Implementation and Its Experience of Open Radiopharmaceutical Source for Metastatic Prostate Cancer Treatment in Small Radiation Oncology Clinic

Predicting Response to [177Lu]Lu-PSMA Therapy in mCRPC Using Machine Learning.

Radioligandtherapy (RLT) with [177Lu]Lu-PSMA has been newly introduced as a routine treatment for metastatic castration-resistant prostate cancer (mCRPC). However, not all patients can tolerate the entire therapeutic sequence, and in some cases, the treatment may prove ineffective. In real-world conditions, the aim is to distinguish between patients who fully benefit from treatment (those who respond effectively and tolerate the entire therapeutic sequence) and those who do not respond or cannot tolerate the entire sequence. This study explores predictive factors to distinguish between fully beneficial RLT treatment patients (FBTP) and not fully beneficial RLT treatment patients (NFBTP). The objective was to enhance the understanding of predictive factors influencing RLT effectiveness and to highlight the significance of machine learning in optimizing patient selection for treatment planning. Data from 25 mCRPC patients, categorized as FBTP (11) or NFBTP (14) to RLT, were analyzed. The dataset included clinical, imaging, and biological parameters. Data analysis techniques, including exploratory data analysis and feature engineering, were used to develop machine learning models for predicting patient outcomes. Imaging data analysis revealed statistically significant differences in the renal uptake intensity of Choline between the two groups. A discordance of FDG+ and PSMA- was identified as a potential indicator of NFBTP. The integration of biological data enhanced the model's predictive capability, achieving an accuracy of 0.92, a sensitivity of 0.96, and a precision of 0.96. Adding blood parameters like neutrophils, leukocytes, and alkaline phosphatase greatly increased prediction accuracy. This study emphasizes the significance of an integrated approach that merges imaging and biological data, thereby augmenting the predictive accuracy of patient outcomes in RLT with [177Lu]Lu-PSMA. In particular, including Choline PET among the imaging parameters provides unique insights into the predictive factors affecting RLT efficacy. This approach not only deepens the understanding of predictive factors but also underscores the utility of machine learning in refining the patient selection process for optimized treatment planning.