Decrease In Prostate-specific Antigen Levels Research Articles

Initial [18F]DCFPyL PET/CT in treatment-naïve prostate cancer: correlation with post-ADT PSA outcomes and recurrence.

Positron emission tomography (PET) with prostate-specific membrane antigen (PSMA) targeting tracers has emerged as a valuable diagnostic tool for prostate cancer (PCa), androgen deprivation therapy (ADT) stands as the cornerstone treatment for advanced PCa, yet forecasting the response to hormonal therapy poses a significant clinical hurdle. In a prospective cohort of 86 PCa patients undergoing short-term ADT, this study evaluated the prognostic potential of [18F]DCFPyL PET/CT scans. Comprehensive data encompassing clinical profiles, baseline prostate-specific antigen (PSA) levels, and imaging metrics were assessed. We developed predictive models for assessing decreases in PSA levels (PSA50 and PSA70) based on a combination of PET-related parameters and clinical factors. Kaplan-Meier survival analysis was utilized to ascertain the prognostic value of PET-based metrics. In this study, elevated [18F]DCFPyL uptake within the primary tumor, as indicated by a SUV ≥ 6.78 (p = 0.0024), and a reduction in the tumor volume (TV) of primary PSMA-avid tumor with PSMA-TV < 41.96 cm3 (p = 0.038), as well as an increased burden of metastatic PSMA-avid tumor, with PSMA-TV (PSMA-TV ≥ 71.39 cm3) (p = 0.012) were identified in association with diminished progression-free survival (PFS). PET and clinical parameters demonstrated constrained predictive capacity for PSA50 response as indicated by an area under the curve (AUC) of 0.442. Our study revealed that pretreatment [18F]DCFPyL uptake in primary or metastatic tumor sites is prognostically relevant in high-risk PCa patients undergoing ADT. Further research is needed to develop robust predictive models in this multifaceted landscape of PCa management.

Real-world retrospective study of prostate-specific antigen and safety assessment with darolutamide plus androgen deprivation therapy for metastasis hormone-sensitive prostate cancer.

ARASENS has demonstrated the efficacy and safety for darolutamide (DARO) with androgen deprivation therapy (ADT) plus docetaxel in metastasis hormone-sensitive prostate cancer (mHSPC). There is a lack of reports for DARO with ADT in mHSPC though the regimen is used in clinical from time to time. Moreover, recent studies have supported the importance of early and rapid prostate-specific antigen (PSA) reduction, which correlates with reduced disease progression and improved survival in patients with mHSPC. This study aims to evaluate PSA reduction as a primary endpoint for DARO with ADT in the treatment of mHSPC and to evaluate the real-world short-term PSA control of DARO with ADT from two leading medical centers in China. We retrospectively reviewed the clinical records of patients with mHSPC receiving ADT and DARO (600 mg, b.i.d.). The collection of data spanned from March 1, 2022, to July 31, 2023. The main observation indicators were PSA level and drug-related adverse events (AE) after medication. PSA levels were closely monitored prior to treatment initiation and at 2-week intervals, as well as at 1, 3, and 6 months after the initiation of treatment. We also conducted an analysis to determine the proportion of patients achieving a PSA reduction of 50% or more (PSA50) and 90% or more (PSA90) as well as the percentage of patients with a notable decrease in PSA level to 0.2 ng/mL and PSA nadir of ≤0.02 ng/mL. Fifty-one patients were included in the study, with a median age of 73 years. At diagnosis of HSPC, the majority of patients had a Gleason score ≥8 (n=40, 78.40%) and a median baseline PSA level of 88 ng/mL. Approximately 45.1% (n=23) of patients had a Charlson Comorbidity Index over 1 and were receiving one or more nontumor-related treatments. The median follow-up time was 9.3 months (range, 1.16-15.8 months). The median reductions in PSA levels compared to baseline were 84.37%, 91.48%, 94.67% and 99.81% at 2 weeks, 1 month, 3 months and 6 months after administration of DARO with ADT, respectively. The median time to PSA50, PSA90, significant PSA reduction (PSA <0.2 ng/mL), and PSA nadir (PSA <0.02 ng/mL) was 0.97, 1.27, 1.98, and 2.08 months, respectively. AE mainly included fatigue (two patients) and arm pain (one patient), all of which were grade I or II AE. No grade III or AE were observed. For treating prostate cancer, DARO with ADT has good early efficacy, demonstrating prompt and substantial control of PSA levels, with a favorable safety profile.

Prostate-specific antigen (PSA) decline with apalutamide therapy is associated with longer survival and improved outcomes in individuals with metastatic prostate cancer: a plain language summary of the TITAN study.

This summary describes the results from an additional (or post hoc) analysis of the TITAN study. The TITAN study looked at whether the prostate cancer treatment apalutamide could be used to treat individuals with metastatic castration-sensitive prostate cancer (or mCSPC). A total of 1052 participants with mCSPC were included in the TITAN study. Treatment with apalutamide was compared with treatment with placebo. All participants received androgen deprivation therapy (or ADT), which is a type of hormone therapy that has been part of the main treatment for mCSPC for many years. The results showed that apalutamide plus ADT increased the length of time that participants remained alive compared with placebo plus ADT. Apalutamide plus ADT also controlled the growth of the cancer for a longer length of time compared with placebo plus ADT. Additionally, participants who received apalutamide plus ADT experienced a greater reduction in the blood levels of prostate-specific antigen (or PSA), called a deep PSA decline, compared with those who received placebo plus ADT. An additional (or post hoc) analysis was carried out to understand whether a decrease in blood PSA levels, in response to treatment, was associated with improved outcomes, including longer survival time. In participants who received apalutamide plus ADT, a deep PSA decline in response to treatment was associated with longer survival time and improved outcomes. These results demonstrate that individuals with mCSPC can benefit from treatment with apalutamide plus ADT. The association seen between deep PSA decline and the longer survival time and improved outcomes highlights how PSA measurements can be used to help monitor cancer disease evolution in response to treatment. Monitoring PSA levels will assist doctors and other healthcare professionals to understand how effectively a treatment is working for a patient and to tailor their treatment approach to improve PSA decline.

Fluorine-18 prostate-specific membrane antigen-1007-avid indeterminate bone lesions in prostate cancer: clinical and PET/CT features to predict outcomes and prognosis

To determine clinical and fluorine-18 prostate-specific membrane antigen-1007 (18F-PSMA-1007) integrated positron-emission tomography (PET)/computed tomography (CT) features that could be used to interpret indeterminate bone lesions (IBLs) and assess the prognosis of prostate cancer (PCa) in patients with IBLs. Consecutive patients who underwent PSMA PET/CT were analysed retrospectively. IBLs were identified as benign or malignant based on follow-up imaging and clinical management. Lesion- and patient-based assessments were performed to define features predictive of bone lesion results and determine clinical risk. Patients' prognosis was analysed based on clinical characteristics, including prostate-specific antigen (PSA) and alkaline phosphatase (ALP), respectively. A total of 105 patients (mean age ± SD, 72.1±8 years) were evaluated and 158 IBLs were identified. Fifty-three (33.5%), 36 (22.8%), and 69 (43.7%) IBLs were benign, malignant, and equivocal, respectively. Variables including location, maximum standard uptake value (SUVmax), and lymph node metastases (LNM) were related to the benignancy or malignancy of IBLs (p=0.046, p<0.001 and p<0.001, respectively). Regression analysis indicated that LNM, SUVmax, and location of IBLs could be predictors of lesion interpretation (p<0.001, p=0.002 and p=0.035). Patients with benign IBLs experienced the most considerable decreases in PSA and ALP levels. LNM, SUVmax, and location may contribute to IBL interpretation. A rapid decrease in PSA and ALP levels might suggest a better prognosis for patients with benign IBLs.

Possible non-linear relation between prostate specific antigen and vitamin D: a machine learning study based on cross-section data.

Objective: Due to inconsistent results in earlier investigations regarding the relationship between vitamin D and prostate-specific antigen (PSA), this study was conducted to gain a deeper understanding of the association between vitamin D and PSA. Methods: A total of 7174 male samples with 25(OH)D, PSA, and other variables were obtained from the National Health and Nutrition Examination Survey (NHANES) database. Three models, created through stepwise logistic regression, were employed to examine the dose-response association between PSA and 25(OH)D. Subsequently, restricted cubic spline analysis (RCS) was used to explore the nonlinear association between 25(OH)D and PSA. The study also compared the performance of four machine learning models in predicting PSA levels. Results: The dose-response relationship indicated a negative impact of high 25(OH)D levels on PSA (p for trend 0.05). The odds ratio (OR) of Q4 (7.73 with 95% CI (0.26, 15.76)) was significantly higher than Q1 (6.23 with 95% CI (0.24, 12.57)). OR values in Q2 and Q3 were less than 1 (Q2= 0.57 with 95% CI (-6.37, 8.04) and Q3= 0.26 with 95% CI (-5.94, 6.86)), suggesting a potential protective effect of 25(OH)D on PSA. RCS analysis revealed a U-shaped relationship between blood 25(OH)D levels and PSA, with serum 25(OH)D in the range of 20-134 ng/ml showing a potential decrease in PSA levels. Above this range, an increase in 25(OH)D might elevate PSA levels. Age (2.67 with 95% CI 2.24 to 3.1) and BMI (17.52 with 95% CI 7.65 to 26.32), along with the OR of obesity (10.36 with 95% CI 0.68 to 20.18), were identified as potential PSA risk factors. Among the machine learning models, the random forest algorithm performed the best in predicting PSA levels. Conclusion: This study revealed a U-shaped relationship between 25(OH)D and PSA, with PSA potentially declining when 25(OH)D is between 20 and 134 ng/mL and possibly rising above this range. The random forest method proved effective in both predicting PSA levels and guiding vitamin D dosage.

Targeted Inhibition of CYP11A1 in Castration-Resistant Prostate Cancer

BackgroundProstate 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).MethodsCYPIDES 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.ResultsNinety-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.ConclusionsODM-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.)

Illustration of association between change in prostate-specific antigen (PSA) values and time to tumor status after treatment for prostate cancer patients: a joint modelling approach

BackgroundProstate cancer (PCa) is the most prevalent tumor in men, and Prostate-Specific Antigen (PSA) serves as the primary marker for diagnosis, recurrence, and disease-free status. PSA levels post-treatment guide physicians in gauging disease progression and tumor status (low or high). Clinical follow-up relies on monitoring PSA over time, forming the basis for dynamic prediction. Our study proposes a joint model of longitudinal PSA and time to tumor shrinkage, incorporating baseline variables. The research aims to assess tumor status post-treatment for dynamic prediction, utilizing joint assessment of PSA measurements and time to tumor status.MethodsWe propose a joint model for longitudinal PSA and time to tumor shrinkage, taking into account baseline BMI and post-treatment factors, including external beam radiation therapy (EBRT), androgen deprivation therapy (ADT), prostatectomy, and various combinations of these interventions. The model employs a mixed-effect sub-model for longitudinal PSA and an event time sub-model for tumor shrinkage.ResultsResults emphasize the significance of baseline factors in understanding the relationship between PSA trajectories and tumor status. Patients with low tumor status consistently exhibit low PSA values, decreasing exponentially within one month post-treatment. The correlation between PSA levels and tumor shrinkage is evident, with the considered factors proving to be significant in both sub-models.ConclusionsCompared to other treatment options, ADT is the most effective in achieving a low tumor status, as evidenced by a decrease in PSA levels after months of treatment. Patients with an increased BMI were more likely to attain a low tumor status. The research enhances dynamic prediction for PCa patients, utilizing joint analysis of PSA and time to tumor shrinkage post-treatment. The developed model facilitates more effective and personalized decision-making in PCa care.

Androgen receptor signaling mechanism in prostate cancer: resistance to antiandrogen therapy and association with DNA repair genes

Background. Metastatic castration-resistant prostate cancer remains a complex problem due to patients' previous treatments and limited selection of subsequent therapies. While 2nd generation antiandrogens are initially effective, resistance to them is not an exceptional event. Mechanisms depending on androgen receptor and independent of it have been described. A special focus is on mutations in DNA repair genes, particularly genes involved in homologous recombination repair (HRR) as a possible cause of somatic genetic abnormalities specifically in progressive metastatic disease. However, data on the effect of the HRR defect on the effectiveness of antiandrogen therapy for prostate cancer are very limited, which requires additional clinical studies.Aim. To evaluate the effect of clinical, morphological, molecular and genetic factors on the effectiveness of enzalutamide antiandrogen therapy in patients with prostate cancer and known mutations in DNA repair genes involved in HRR and mismatch repair.Materials and methods. The study was performed at the Clinical Oncological Dispensary No. 1 (Krasnodar). Retrospective analysis of clinical and morphological parameters of 54 patients with prostate cancer who received enzalutamide antiandrogen therapy and with known status of germ line and somatic mutations of HRR DNA repair genes (BRCA1, BRCA2, ATM, BARD, BRIP1, CDK12, CHEK1, CHEK2, PALB2, RAD51B, RAD51C, RAD54L, FANCL) and microsatellite instability in immunohistochemical determination of mismatch repair deficit was performed. Statistical analysis was performed using IBM SPSS Statistics v.22 software.Results and conclusion. In 17 of 54 patients, pathogenic germline and somatic mutations of HRR genes were detected: 7 mutations in BRCA2 gene, 4 - in CHEK2, 2 - in BRCA1, 2 - in CDK12, 1 - in BRIP1 and 1 - in ATM. It was shown that in the group of patients with metastatic castration-resistant prostate cancer, histological grade per the International Society of Urological Pathology (ISUP) G2 (total Gleason score 7 (3 + 4)) is significantly associated with the absence of HRR mutation, and grade G3 (total Gleason score 7 (4 + 3)) was associated with HRR mutations (р &lt;0.05). Increase in prostate-specific antigen (PSA) level/biochemical progression 12-16 weeks after enzalutamide therapy start was significantly associated with metastatic castration-resistant prostate cancer without HRR mutations (р &lt;0.05). In case of tumor response to enzalutamide therapy, decrease in PSA level did not depend on the age of disease onset, differentiation grade, primary advancement, previous docetaxel treatment, and presence of HRR mutation. Cox multivariate regression test showed that prescription of docetaxel before enzalutamide increased the risk of PSA-progression (hazard ratio (HR) 5.160; 95 % confidence interval (CI) 1.549-17.189; р = 0.008) and radiographic progression (HR 5.161; 95 % CI 1.550-17.187; р = 0.008). Progression risk decreased with increased level of PSA decrease 12-16 weeks after enzalutamide therapy start: for PSA decrease &gt;30 % HR 0.150; 95 % CI 0.040-0.570; р = 0.005; for PSA decrease &gt;50 % HR 0.039; 95 % CI 0.006-0.280; р = 0.001; for PSA decrease &gt;90 % HR 0.116; 95 % CI 0.036-0.375; р = 0.000. Presence of HRR mutation, age &lt;58 years, primary metastatic disease and poorly differentiated morphology did not affect duration without PSA-progression (p &gt;0.05). Kaplan-Meier curves showed a trend towards increased time to development of castration resistance in the group of primary early cancer (Breslow р = 0.06; Tarone-Ware р = 0.062). Subgroup analysis showed that in the cohort of patients with castration-resistant prostate cancer (n = 48), absence of HRR mutation in patients who previously received docetaxel therapy increases time to PSA-progression compared to patients with mutations (log-rank р &lt;0.05).

Abstract 3904: Simvastatin intensifies anti-androgen efficacy against treatment-resistant prostate cancer cells

Abstract Androgen receptor (AR) signaling inhibitors (ARSIs) bicalutamide (Bic) and enzalutamide (Enza) are used in the treatment of castration resistant prostate cancer (CRPC). Prostate cancer (PCa) cells eventually develop treatment resistance against these drugs causing clinical challenges. The mechanisms behind treatment resistance are complex and only partially known. Androgen signaling is linked to lipid and cholesterol metabolism, and they likely play a role in the development of treatment resistance. Cholesterol producing mevalonate pathway can be inhibited by statins, but it is unknown whether statin treatment could enhance effects of ARSIs. We studied combined effects of simvastatin (Sim) with or without Bic or Enza in VCaP originated PCa cell lines resistant to these ARSIs. Unique treatment resistant cell lines were created with long-term cultures of VCaP cells. The cells were kept under anti-androgen influence until the cells were growing normally despite the ARSIs. We analyzed changes in cell growth, RNA expression, and relevant AR signaling and cholesterol metabolism protein expression. Prostate-specific antigen (PSA) secretion was measured as a marker of AR signaling activity. In Bic or Enza resistant cell lines, combination of 2.5 or 5 μM simvastatin + 10 μM Bic/Enza decreased cell growth more than Sim alone, i.e., ARSIs demonstrated efficacy in combination therapy against ARSI resistant cells. In Bic and Enza resistant cells, combination treatment increased the expression of 60 and 26 and decreased the expression of 33 and 48 genes, respectively, compared with simvastatin alone. Altogether, 16 genes expression changed similarly in both cell lines in response to combination therapy. In both cell lines, over 70% of all gene changes were seen on AR-regulated genes. In Bic resistant cells, Sim decreased PSA levels with or without Bic. On the contrary, in Enza resistant cells PSA levels were increased with combination of Sim and Enza. We showed that combined treatment with ARSI and Sim inhibited cell growth more than Sim alone in ARSI resistant cell lines. This suggests that inhibition of the mevalonate pathway could enhance androgen signaling inhibition and potentially circumvent ARSI resistance mechanisms. This phenomenon is supported by epidemiological studies as patients treated with anti-androgens responded better during simultaneous statin treatment. Gene expression differed in combination treatment compared to Sim alone. Future studies are needed on whether interventions on lipid and cholesterol metabolism could enhance treatment of CRPC. Knowledge about the precise mechanisms behind the treatment responses and resistance might lead to new therapeutic applications. Citation Format: Aino Siltari, Olga Korhonen, Paavo Raittinen, Merja Bläuer, Heimo Syvälä, Teuvo L. Tammela, Teemu J. Murtola. Simvastatin intensifies anti-androgen efficacy against treatment-resistant prostate cancer cells. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3904.

Head-to-head comparisons of [68Ga]Ga-PSMA-11 PET/CT, multiparametric MRI, and prostate-specific antigen for the evaluation of therapeutic responses to neoadjuvant chemohormonal therapy in high-risk non-metastatic prostate cancer patients: a prospective study.

The optimal tool to evaluate the tumour therapeutic responses to neoadjuvant chemohormonal therapy (NCHT) in patients with high-risk non-metastatic prostate cancer (PCa) remains uncertain. We compared the role of [68Ga]-labeled prostate-specific membrane antigen (PSMA)-11 positron emission tomography/computerized tomography ([68Ga]Ga-PSMA-11 PET/CT), multiparametric MRI (mpMRI), and prostate-specific antigen (PSA) and assessed the practical value of the recent European Association of Urology and European Association of Nuclear Medicine (EAU/EANM) recommended criteria of PSMA PET/CT to evaluate the therapeutic responses to NCHT in patients with high-risk non-metastatic PCa. This prospective study included 72 high-risk non-metastatic PCa patients receiving NCHT followed by radical prostatectomy from June 2021 to March 2022. PSA testing, [68Ga]Ga-PSMA-11 PET/CT, and mpMRI scanning were conducted in all patients before and after NCHT. Therapeutic responses to NCHT were evaluated with PSA, RECIST 1.1, PERCIST 1.0, and EAU/EANM recommended criteria. Postoperative pathological results were considered the reference standard. A favourable pathological response was defined as pathologic complete remission (pCR) or minimal residual disease (MRD). Diagnostic accuracy was assessed by sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), positive predictive value (PPV), negative predictive value (NPV), and Cohen's kappa index. Logistic regression analysis was used to determine the independent predictive value of [68Ga]Ga-PSMA-11 PET/CT-derived parameters. All cases experienced a marked decrease in PSA levels after NCHT. Twenty-four (33.33%) cases experienced a favourable pathological response, including five (6.94%) cases of pCR and 19 (26.39%) cases of MRD. According to the results of [68Ga]Ga-PSMA-11 PET/CT, EAU/EANM recommended criteria indicated that 20 (27.78%) cases had a CR, whereas PERCIST 1.0 criteria indicated that 23 (31.94%) cases had a CR. There was a strong association between EAU/EANM recommended criteria and PERCIST 1.0 criteria (Pearson's R=0.857). The sensitivity (75.00%, 79.17% vs. 58.33%, 58.33%), specificity (95.83%, 91.67% vs. 83.33%, 68.75%), PLR (18.00, 9.50 vs. 3.50, 1.87), NLR (0.26, 0.23 vs. 0.50, 0.61), PPV (90.0%, 82.6% vs. 63.6%, 48.3%), and NPV (88.5%, 89.8% vs. 80.0%, 76.7%) of [68Ga]Ga-PSMA-11 PET/CT (including EAU/EANM recommended criteria and PERCIST 1.0 criteria) to predict favourable pathological responses were all superior to those of mpMRI and nadir PSA. The kappa index to predict a favourable pathological response was 0.257 for PSA, 0.426 for RECIST 1.1, 0.716 for PERCIST 1.0, and 0.739 for EAU/EANM recommended criteria. Multivariate logistic analysis revealed that the post-NCHT maximum standardized uptake value (SUVmax) before radical prostatectomy was an independent predictor of a favourable pathological response to NCHT. [68Ga]Ga-PSMA-11 PET/CT had a better concordance with a favourable pathological response to NCHT compared with nadir PSA and mpMRI. EAU/EANM recommended criteria and PERCIST 1.0 criteria performed equally to identify pathological responders when [68Ga]Ga-PSMA-11 PET/CT was used as a therapeutic response assessment tool.

MCRPC patients with PSA fluctuations under radioligand therapy have comparable survival benefits relative to patients with sustained PSA decrease

IntroductionIn men with metastatic castration-resistant prostate cancer (mCRPC) scheduled for prostate-specific membrane antigen (PSMA)-targeted radioligand therapy (RLT), biochemical response is assessed based on repeated measurements of prostate-specific antigen (PSA) levels. We aimed to determine overall survival (OS) in patients experiencing sustained PSA increase, decrease, or fluctuations during therapy.Materials and methodsIn this bicentric study, we included 176 mCRPC patients treated with PSMA-directed RLT. PSA levels were determined using blood samples prior to the first RLT and on the admission days for the following cycles. We calculated relative changes in PSA levels compared to baseline. Kaplan–Meier curves as well as log-rank test were used to compare OS of different subgroups, including patients with sustained PSA increase, decrease, or fluctuations (defined as change after initial decrease or increase after the first cycle).ResultsSixty-one out of one hundred seventy-six (34.7%) patients showed a sustained increase and 86/176 (48.8%) a sustained decrease in PSA levels. PSA fluctuations were observed in the remaining 29/176 (16.5%). In this subgroup, 22/29 experienced initial PSA decrease followed by an increase (7/29, initial increase followed by a decrease). Median OS of patients with sustained decrease in PSA levels was significantly longer when compared to patients with sustained increase of PSA levels (19 vs. 8 months; HR 0.35, 95% CI 0.22–0.56; P < 0.001). Patients with PSA fluctuations showed a significantly longer median OS compared to patients with sustained increase of PSA levels (18 vs. 8 months; HR 0.49, 95% CI 0.30–0.80; P < 0.01), but no significant difference relative to men with sustained PSA decrease (18 vs. 19 months; HR 1.4, 95% CI 0.78–2.49; P = 0.20). In addition, in men experiencing PSA fluctuations, median OS did not differ significantly between patients with initial decrease or initial increase of tumor marker levels (16 vs. 18 months; HR 1.2, 95% CI 0.38–4.05; P = 0.68).ConclusionInitial increase or decrease of PSA levels is sustained in the majority of patients undergoing RLT. Sustained PSA decrease was linked to prolonged survival and men with PSA fluctuations under treatment experienced comparable survival benefits. As such, transient tumor marker oscillations under RLT should rather not lead to treatment discontinuation, especially in the absence of radiological progression.

Abstract 3318: PSMA-targeted thorium-227 conjugate (PSMA-TTC) inhibits tumor growth and abnormal bone changes in the intratibial LNCaP xenograft model of bone-metastatic prostate cancer

Abstract Prostate-specific membrane antigen (PSMA) is a transmembrane glycoprotein specifically overexpressed on the cell membrane of prostate cancer cells. PSMA-targeted thorium-227 conjugate (PSMA-TTC, BAY 2315497) consists of a human PSMA-targeting antibody covalently linked to a 3,2-HOPO (hydroxypyridinone) chelator moiety, radiolabeled with alpha-particle emitting thorium-227. Previous studies have demonstrated PSMA-TTC to be an attractive therapy option for patients with metastatic castration-resistant prostate cancer (mCRPC). In this study, we investigated the efficacy of PSMA-TTC in the LNCaP intratibial model mimicking prostate cancer metastasized to bone. LNCaP prostate cancer cells were inoculated into the right tibiae of male NOD.scid mice. The mice were randomized to treatment groups (n=12/group) based on serum prostate-specific antigen (PSA) and treated with a single dose of vehicle or PSMA-TTC (300 kBq/kg, 0.75 mg/kg, i.v.). Tumor growth was followed by biweekly serum PSA measurements for 42 days. Tumor-induced abnormal bone growth, PSMA-TTC uptake, bone microarchitecture, bone formation rate and tumor area in tumor-bearing tibiae were determined by radiography, gamma counter, microCT, and dynamic and static histomorphometry, respectively. A single injection of PSMA-TTC efficiently inhibited intratibial tumor growth (p&amp;lt;0.001) as evidenced by a 82.6% decrease from baseline PSA value in the treatment group at the end of the study, whereas the vehicle group increased by 380% from baseline. Furthermore, the tumor-bearing tibiae were heavier (138%) than the non-tumor-bearing tibiae in the vehicle group, whereas in the PSMA-TTC-treated mice no such difference was observed (103%). PSMA-TTC decreased tumor-induced abnormal bone area in the tumor-bearing tibiae (43.5% of the vehicle). PSMA-TTC uptake relative to tibia weight was higher in the tumor-bearing tibiae compared with the non-tumor-bearing tibiae, resulting in higher levels of thorium-227 and its daughter isotype radium-223 both 3 days and 3 weeks post injection. In this preclinical study, PSMA-TTC showed robust antitumor efficacy, for the first time, in a model mimicking prostate cancer metastasized to bone as evidenced by a decrease in serum PSA levels, tumor-induced abnormal bone changes, and tumor-bearing tibia weights in the PSMA-TTC-treated mice. PSMA-TTC binds to PSMA-expressing cancer cells, delivering a cytotoxic dose of alpha radiation. The decay product of thorium-227, radium-223 binds to bone matrix and this could also contribute to the antitumor efficacy in this bone-metastatic model. Taken together, our data indicate activity of PSMA-TTC in bone-metastatic CRPC. PSMA-TTC as a monotherapy as well as in combination with darolutamide is currently being investigated in patients with mCRPC in a phase 1 clinical trial (NCT03724747). Citation Format: Christoph Schatz, Mari I. Suominen, Matias Knuuttila, Sabine Zitzmann-Kolbe, Jukka Rissanen, Sanna-Maria Käkönen, Urs Hagemann, Arne Scholz. PSMA-targeted thorium-227 conjugate (PSMA-TTC) inhibits tumor growth and abnormal bone changes in the intratibial LNCaP xenograft model of bone-metastatic prostate cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3318.

Abstract 4: Intercepting ribosomal protein S6KB1 signaling: Prevention of prostate cancer recurrence

Abstract There is an urgent need for innovative strategies such as the discovery of adjuvants that can prevent relapse and improve quality of life for patients treated with radiotherapy. Previously we demonstrated the utility of Nexrutine (Nex) as a neo-adjuvant with radiation. Nex was safe and well tolerated in PCa patients and potentiated radiation response in part through downregulation of ribosomal protein S6K (encoded byRPS6KB1). We now show that RPS6KB1 depleted prostate cancer cells with higher basal levels of γ-H2AX, a marker for DNA double strand breaks (i) are more sensitive to radiation and (ii) form smaller tumors with reduced levels of prostate specific antigen (PSA). Depletion of RPS6KB1 hindered DNA double-strand break repair predominantly through the alternate end-joining pathway, induction of G2/M checkpoint and NFκB pathway activation. Collectively these events led to improved radiation sensitivity. We further identified Berberine (Ber), one of the active constituents of Nex as a potential pharmacological inhibitor of RPS6KB1. In an orthotopic implantation model of C4-2B, treatment with Ber alone or Ber plus radiation decreased PSA levels that was sustained during the course of the experiment. On the other hand animals treated with radiation alone developed recurrent cancer as evidenced by a resurgence of PSA. Animals administered Ber followed by XRT intervention had increased levels of RANTES while there was no change in animals that received XRT followed by Ber. The observed reversal of the Bereffect with the sequence of intervention is statistically significant (p=0.0298). Among animals not subject to XRT, the mean PSA increased in those that did not receive Ber relative to those that did; mean difference=-1.93, 95% CI -3.75 to -0.105, p=0.04 with no significant changes in body weight. Notably,RPS6KB1 mRNA levels increased in tumor samples in patients experiencing biochemical recurrence(BCR). Given that rising PSA following conventional therapeutic approaches such as radiation remain a major clinical challenge, targeting RPS6KB1 signaling with radiation therapy is an attractive strategy to prevent BCR. Supported in part by CPRIT RP190012 (APK). Citation Format: Addanki Pratap Kumar, Alison Clark, Michelle Villarreal, Sridharan Jayamohan, Shih-Bo Huang, Suleman S. Hussain, Xiaoyu Yang, Paul Rivas, Darpan Patel, Bethany L. Pierce, Shreya Tripathy, Pawel Osmulski, Maria Gaczynska, Lai Zhao, Li-Ju Wang, Yidong Chen, Caroline Xavier Paul Ezhilan, Mohan Natarajan, Joel E. Michalek, Robert L. Reddick, Rita Ghosh. Intercepting ribosomal protein S6KB1 signaling: Prevention of prostate cancer recurrence [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 4.

The Safety of Human Chorionic Gonadotropin Monotherapy Among Men With Previous Exogenous Testosterone Use.

Background and objectiveHuman chorionic gonadotropin (hCG) is homologous to luteinizing hormone (LH) and stimulates endogenous testosterone (T) production. Current American Urological Association (AUA) guidelines recommend hCG for T-deficient men who wish to preserve their fertility. However, there is no data available regarding the long-term efficacy and safety of hCG monotherapy in men with a history of exogenous T use. We hypothesized that transitioning to hCG would be a safe and effective option in this population.MethodologyWe performed a retrospective analysis involving 28 men with previous exogenous T use who were switched to hCG monotherapy and underwent follow-up lab work at least one month later. We evaluated changes in hormones [T, LH, follicle-stimulating hormone (FSH), and estradiol], hematocrit (HCT), glycated hemoglobin (HbA1c), and prostate-specific antigen (PSA).ResultsAmong the entire cohort, we found no significant change in mean hormone levels (including T), HbA1c, or PSA. There was a significant (p<0.05) decrease in HCT (45.27 ±4.06 to 44.16 ±3.48%, n=15). No thromboembolic events were reported. Additionally, among men who had their baseline labs completed outside their previous T therapy therapeutic time window prior to starting hCG monotherapy, there was a statistically significant increase in mean T levels (307.36 ±148.74 to 422.11 ±268.15 ng/dL, n=30 and 31, pre- and post-hCG, respectively) and a statistically significant decrease in mean PSA levels (0.91 ±0.35 to 0.69 ±0.23 ng/mL, n=5).ConclusionsThese results suggest that hCG is a safe and effective alternative to traditional T therapy for men with a history of exogenous T use and may lead to an advantageous decrease in HCT. hCG may serve as an alternative form of T therapy with a lower risk for secondary erythrocytosis, and further research is warranted to gain deeper insights into the topic.

Effects of Saw Palmetto Therapy on some Inflammatory Biomarkers in a Sample of Iraqi Male with Symptomatic Benign Prostatic Hyperplasia

Background Saw palmetto contains powerful anti-inflammatory components commonly used in Benign prostatic hyperplasia (BPH) patients with symptoms. The current study was designed to assess the effectiveness of saw palmetto alone or supplementation&#x0D; &#x0D; therapy with tamsulosin via measurement of some inflammatory biomarker in male with lower urinary tract symptoms (LUTS) consistent with (BPH).&#x0D; Methods The present study is an interventional prospective randomized enrolled newly diagnosed patients with moderate to severe symptomatic BPH. The eligible 60 patients were allocated into (3) groups, each group with (20) patients; Group (1) treated with Saw palmetto cap (320 mg); Group (2) treated with Saw palmetto cap (320 mg) and tamsulosin (0.4mg); Group (3) treated with tamsulosin (0.4mg), protocols to be given once daily for 12 weeks. Measurement of prostate specific antigen (PSA), C-reactive protein (CRP), and interleukin 6 (IL-6) was done.&#x0D; Results There was significant decrease in the serum PSA, CRP and IL-6 level (P&lt;0.01) in group1 and 2 patients only after treatment when compared to pretreatment. Patients on combination therapy presented with high percent of change compared to other groups. No change in CRP and IL-6 level in patients on tamsulosin alone.&#x0D; Conclusion From the findings of the present study, phytotherapy with Saw Palmetto alone or as supplement produced significant 3 months drop in both inflammatory markers, the total CRP level and IL-6 level. Also produced significant decrease in PSA level, and may substitute the conventional therapy in mild disease status.

Activity and safety of SHR3680, a novel antiandrogen, in patients with metastatic castration-resistant prostate cancer: a phase I/II trial

BackgroundAntagonizing the androgen-receptor (AR) pathway is an effective treatment strategy for patients with metastatic castration-resistant prostate cancer (CRPC). Here, we report the results of a first-in-human phase 1/2 study which assessed the safety, pharmacokinetics, and activity of SHR3680 (a novel AR antagonist) in patients with metastatic CRPC.MethodsThis phase 1/2 study enrolled patients with progressive metastatic CRPC who had not been previously treated with novel AR-targeted agents. In the phase 1 dose-escalation portion, patients received oral SHR3680 at a starting daily dose of 40 mg, which was subsequently escalated to 80 mg, 160 mg, 240 mg, 360 mg, and 480 mg per day. In phase 2 dose-expansion portion, patients were randomized to receive daily dose of 80 mg, 160 mg, or 240 mg of SHR3680. The primary endpoint in phase 1 was safety and tolerability and in phase 2 was the proportion of patients with a prostate-specific antigen (PSA) response (≥ 50% decrease of PSA level) at week 12.ResultsA total of 197 eligible patients were enrolled and received SHR3680 treatment, including 18 patients in phase 1 and 179 patients in phase 2. No dose-limiting toxicities were reported and the maximum tolerated dose was not reached. Treatment-related adverse events (TRAEs) occurred in 116 (58.9%) patients, with the most common one being proteinuria (13.7%). TRAEs of grade ≥ 3 occurred in only 23 (11.7%) patients, and no treatment-related deaths occurred. Antitumor activities were evident at all doses, including PSA response at week 12 in 134 (68.0%; 95% CI, 61.0–74.5) patients, stabilized bone disease at week 12 in 174 (88.3%; 95% CI, 87.2–95.5) patients, and responses in soft tissue lesions in 21 (34.4%, 95% CI, 22.7–47.7) of 61 patients.ConclusionSHR3680 was well tolerated and safe, with promising anti-tumor activity across all doses tested in patients with metastatic CRPC. The dose of 240 mg daily was recommended for further phase 3 study.Trial registrationClinicaltrials.gov NCT02691975; registered February 25, 2016.

MCRPC Patients Receiving 225Ac-PSMA-617 Therapy in the Post-Androgen Deprivation Therapy Setting: Response to Treatment and Survival Analysis.

225Ac-PSMA-617, targeting the prostate-specific membrane antigen (PSMA), which is overexpressed on prostate cancer cells, has shown a remarkable therapeutic efficacy in heavily pretreated patients with metastatic castration-resistant prostate carcinoma (mCRPC). Here, we report on treatment outcome and survival using this novel treatment modality in a series of 53 patients with mCRPC directly after their androgen deprivation treatment (ADT). Methods: 225Ac-PSMA-617 was administered to 53 such patients. 68Ga-PSMA PET/CT was obtained at baseline, before every treatment cycle, and on follow-up to select patients for treatment, determine the activity to be administered, and assess their response. Serial prostate-specific antigen (PSA) measurements were obtained for response assessment. Results: The median age of the patients was 63.4 y (range, 45-83 y). In total, 167 cycles were administered (median, 3; range, 1-7). Forty-eight patients (91%) had a PSA decline of at least 50%, and 51 patients (96%) had any decline in PSA. 68Ga-PSMA PET findings became negative in 30 patients. In the multivariate analysis, a PSA decline of at least 50% proved predictive of both progression-free survival (PFS) and overall survival (OS), and platelet count also proved predictive for PFS. The median estimated OS was 9 mo for patients with a PSA decline of less than 50% but was not yet reached at the latest follow-up (55 mo) for patients with a PSA decline of 50% or more. The estimated median PFS was 22 mo for patients with a PSA decline of at least 50% and 4 mo for patients with a PSA decline of less than 50%. No severe hematotoxicity was noted, and only 3 patients had grade III-IV nephrotoxicity. The commonest toxicity seen was grade I-II xerostomia, observed in 81% of patients. Conclusion: In 91% of 53 patients with mCRPC, treatment with 225Ac-PSMA-617 immediately after ADT resulted in at least a 50% decrease in PSA level. Furthermore, a PSA decline of at least 50% proved the single most important factor predicting PFS and OS after 225Ac-PSMA-617 treatment. Of interest, median OS in patients with a PSA decline of at least 50% was not yet reached at the latest follow-up (55 mo). These favorable results suggest that it would be of major clinical relevance to perform a prospective randomized study comparing 225Ac-PSMA-617 with current standard-of-care treatment options such as enzalutamide, abiraterone acetate, and docetaxel after ADT.

Modern principles of diagnosis and treatment of patients with neuroendocrine carcinoma of the prostate

Background. Prostate cancer (PCa) is well-known as the 2nd leading cause of death from malignant neoplasms among the males from developed countries. One of the variants of the disease - neuroendocrine carcinoma of the prostate (NECP) -manifests itself as the form of castration-resistant PCa. Distinctive manifestations of NECP include a low level of serum prostate specific antigen (PSA), a high potential rate of metastasis, and resistance to hormone replacement therapy. There are very few medical publications on the possibilities of diagnosis and therapy of this type of tumor.The objective of the study is to review the current foundations of pathogenesis, methods of diagnosis and treatment of patients with NECP.Materials and methods. The data of modern medical literature from the PubMed/Crossref archives, from the Elsevier and Scopus databases for 1991-2020 were studied. The materials on the epidemiology and pathogenesis of NECP, as well as the methods of diagnosis and treatment of patients with this pathology are summarized. A comparative analysis of the levels of neuroendocrine markers in castration-resistant and localized forms of PCa was carried out. The schemes of combination therapy of NECP with the use of somatostatin analogs are considered.Results. The detection rate of NECP is reduced due to the blurred clinical picture and morphological characteristics similar to poorly differentiated carcinoma. The basis for the diagnosis of NECP is the determination of the levels of neuronal markers - chromogranin A, neuron-specific enolase, and a number of potentially mitogenic hormones, including PTHrP, NT, serotonin, bombesin, calcitonin, and thyroid-stimulating hormone. The worst prognosis was observed in patients with initially high levels of chromogranin A, which emphasizes the high significance of this indicator for monitoring NECP. The drug of choice in the treatment of patients with this pathology is the somatostatin analogue octreotide-depot, the use of which in combination with hormone replacement therapy leads to stabilization of PCa in 50 % of cases. During therapy with an analogue of somatostatin alone or in cases of tumor progression against the background of chemotherapy, a decrease in PSA level is noted in 50-60 % of cases, and PSA level stabilization - in 41.7-53.3 %.Conclusion. We founded an insufficient number of randomized clinical trials of NECP, therefore, the prognosis of the development of this pathology remains completely unclear. The use of somatostatin analogues, along with targeted therapy, is the main choice of therapy for NECP, but requires further study in the program of randomized trials. If a positive result is obtained, it will be possible to use somatostatin analogs more widely to improve the quality and increase the life expectancy of patients with NECP.

White Button Mushroom Disrupts AR Signaling in Prostate Cancer: The Scientific Basis for a Diet-Based Chemoprevention

Abstract White button mushroom (WBM) (Agaricus bisporus) is a potential prostate cancer (PCa) chemo-preventive and therapeutic agent. Our clinical phase trial of WBM powder in patients with biochemically recurrent PCa indicated that WBM intake reduced the circulating levels of prostate-specific antigen (PSA), with minimal side effects [1]. We hypothesized that WBM exerts its effects on PCa through the androgen receptor (AR) signaling axis. We thus conducted the reverse translational study. Androgen-sensitive PCa cell lines (LNCaP and VCaP) and patient-derived-xenografts (PDX), of a prostate tumor (TM00298) were used. In both LNCaP and VCaP cells, western blots and qRT-PCR assays indicated that WBM extract (6~30 mg/mL) suppressed DHT-induced PSA expression and cell proliferation in a dose-dependent manner. Immunofluorescence on AR revealed that the nuclear localization of AR was reduced upon WBM extract treatment, which agreed with the results of a PSA promotor-luciferase assay, suggesting that WBM extract inhibited DHT-induced luciferase activity. RNA-Seq on WBM-treated LNCaP cells confirmed that WBM treatment suppressed androgen response pathways and cell-cycle control pathways. Our prostate cancer PDX showed that oral intake of WBM extract (200 mg/kg/day) significantly suppressed tumor growth, as well as decreased PSA levels in both tumors and serum. Both in vitro and in vivo studies suggested that chemical(s) in WBM extract behave as AR antagonist(s). We previously identified a conjugated linoleic acid isomer (CLA-9Z11E) as an active component in WBM extract. In the present study, we extended these findings by performing LanthaScreen™ TR-FRET AR Coactivator Interaction Assays for a direct interaction of CLA-9Z11E with AR. We report here that CLA-9Z11E exerts a strong antagonist potency against the recruitment of an AR coactivator peptide towards AR. The inhibitory effect of CLA-9Z11E (IC50: 350 nM) was nearly two times stronger than the known AR antagonist, cyproterone acetate (IC50: 672 nM). The information gained from this study improves the overall understanding of how WBM may contribute to the prevention and treatment of PCa. It also serves as an important, scientific basis for developing diet-based chemoprevention and integrative therapeutic strategies for prostate cancer (supported by NIH R01 CA227230). Reference: [1] Twardowski P, et al. A phase I trial of mushroom powder in patients with biochemically recurrent prostate cancer: Roles of cytokines and myeloid-derived suppressor cells for Agaricus bisporus-induced prostate-specific antigen responses. Cancer. 2015.121(17):2942-50.

Inhibitory effects of Nigella sativa seed oil on the testosterone-induced benign prostatic hyperplasia in rats.

BackgroundBenign prostatic hyperplasia (BPH) is the most prevalent disease of the prostate in elderly men. Since Nigella sativa has been reported to show various pharmacological effects, this study was conducted to examine the effect of N. sativa seed oil on experimental BPH.MethodsThe oil was extracted using the cold-pressing method. Fifty rats were divided into five groups of 10 each as follows: Group 1 orally (p.o.) received normal saline; groups 2–5 were castrated and subcutaneously received 5 mg/kg testosterone propionate for four weeks. Group 2, namely, BPH model, underwent no further treatment, Groups 3 and 4 were treated with 400 mg/kg and 800 mg/kg N. sativa seed oil, Group 5 received finasteride (0.5 mg/kg, p.o.) for 28 days. All groups received repeated testosterone injections for the following four weeks after BPH induction. After the treatments, rats were sacrificed and the prostate tissues removed. Wet weight, prostatic volume (PV) and prostatic index (PI) were determined. Serum prostate-specific antigen (PSA), dihydrotestosterone (DHT), malondialdehyde (MDA) and antioxidant levels were determined.ResultsOur results showed that oral treatment with 400 and 800 mg/kg N. sativa oil led to a significant decrease in PI, PV, DHT concentration, PSA, and serum MDA level, and also significantly increased serum antioxidant capacity.ConclusionsThe study demonstrated that the oil seed exerted anti-BPH effects which may be associated with its antioxidant properties in vivo.