Prostate-specific Antigen Decrease Research Articles

Drugs causing prostate-specific antigen changes: the food and drug administration adverse event reporting system combined with Mendelian randomization analysis

ABSTRACT Background Prostate cancer is one of the most common malignancies in men worldwide, and prostate-specific antigen (PSA) screening is widely used for its early detection. Drug use may affect PSA levels, but the effect for most drugs is currently unknown. Methods This study first investigated drugs related to PSA changes through the Food and Drug Administration Adverse Event Reporting System (FAERs) database, and then used a Mendelian randomization (MR) method to explore the causal relationship between specific drugs and PSA changes using a genome-wide association study (GWAS) data. The statistical analysis software SAS and R were used in the study. Results Through analysis of the FAERs database, 22 drugs were found to be associated with an increase in PSA, and 14 drugs were associated with a decrease in PSA. MR analysis showed that the use of tamsulosin may lead to an increase in PSA. Heterogeneity test, horizontal pleiotropy test and leave-one-out Analysis verified the stability of the results. MR analyses for other drugs did not show statistical significance. Conclusion This study provided a basis for better understanding the impact of medications on prostate health, helping to avoid overdiagnosis or underdiagnosis of high-risk patients. However, research still requires larger-scale validation and in-depth exploration.

Comparison of combination therapy with tamsulosin and dutasteride or finasteride in patients with benign prostatic hyperplasia: a randomized clinical trial

BackgroundBased on our observations at the largest outpatient urology clinic in Iran, patients for whom finasteride is prescribed as a secondary drug to tamsulosin tend to experience earlier and more severe sexual side effects without any difference in the amelioration of symptoms. This study aimed to compare the time lag, efficacy, and side effects of combination therapy with varying doses of dutasteride or finasteride added to tamsulosin for benign prostatic hyperplasia (BPH) treatment.MethodsIn this study 165 were randomized into 5 groups (each N = 33); receiving tamsulosin 0.4mg plus either of A: finasteride 3mg, B: placebo, C: dutasteride 0.25mg, D: finasteride 5mg or E: dutasteride 0.5mg. During the 6-month period of the study, International Prostate Symptom Score (IPSS), post-void residual urine (PVR), International Index of Erectile Function (IIEF-5), prostate volume (PV), prostate specific antigen (PSA) and maximum urinary flow rate (Qmax) were evaluated at baseline and at the 1st, 3rd and 6th month. The differences between each time point and baseline were then compared between groups.ResultsAt 3-month follow-up, group E exhibited a higher decrease in PSA but a greater increase in Qmax compared to group A (p = 0.047 and 0.006, respectively). Group C showed higher Qmax increase compared to group A at 3 and 6 months (p = 0.003 and 0.014) and concurrently a more pronounced PV decrease at 1 and 3 months (p = 0.047 and 0.003, respectively). Group D had a significantly more decrease in their IIEF-5 compared to group A at one-month visit (p = 0.006).ConclusionsIn summary, at the sixth-month follow-up, dutasteride demonstrated superiority over finasteride solely in enhancing Qmax. Therefore, dutasteride may be marginally more beneficial as a secondary component of combination therapy in BPH.Trial registration IRCT, IRCT20120516009772N2. Registered 18 January 2021 Retrospectively registered, https://irct.behdasht.gov.ir/search/result?query=IRCT20120516009772N2.

Apalutamide for non-metastatic castration-resistant prostate cancer (nmCRPC): real world data of a multicenter study

PurposeApalutamide plus androgen-deprivation therapy (ADT) improved outcomes in patients with non-metastatic castration-resistant prostate cancer (nmCRPC). Nevertheless real-world data are limited. The aim of this multicenter study was to generate real-world data from nmCRPC patients treated with ADT plus apalutamide.MethodsIn this observational cohort based investigator initiated trial data of nmCRPC patients receiving apalutamide plus ADT were collected focusing on patient demographic data, prostate-specific antigen (PSA) declines, safety profile including dose modification/discontinuation as well as subsequent therapy and metastasis-free survival (MFS).ResultsData from a total of 31 nmCRPC patients were documented. Compared to the Phase III study Spartan real-world patients are older, showed a higher ECOG-PS and more aggressive tumors. In the cohort PSA decreased about 98.1%, 74% of patients showed a PSA decrease over 90% and 54.8% reached a PSA-level < 0.2ng/ml. Apalutamide was well tolerated in real world patients: adverse events occurred in 67.7% but were in the majority mild (≥ grade 3: 6.5%). Dose reduction was necessary in 38.7% and 32.2% discontinued apalutamide treatment. MFS was 43 months and majority of patients were subsequently treated with abiraterone.ConclusionIn real world more comorbid nmCRPC patients with a higher ECOG-PS and more aggressive tumors are treated with apalutamide plus ADT. Nevertheless efficacy results as well as side effects are similar in real-world compared to Spartan trial showing also a rapid, durable and deep PSA response with a median MFS of 43 months.

First-Strike Rapid Predictive Dosimetry and Dose Response for 177Lu-PSMA Therapy in Metastatic Castration-Resistant Prostate Cancer.

We devised and clinically validated a schema of rapid personalized predictive dosimetry for 177Lu-PSMA-I&T in metastatic castration-resistant prostate cancer. It supersedes traditional empiric prescription by providing clinically meaningful predicted absorbed doses for first-strike optimization. Methods: Prostate-specific membrane antigen PET was conceptualized as a simulation study that captures the complex dosimetric interplay between tumor, marrow, and kidneys at a single time point. Radiation principles of fractionation, heterogeneity, normal-organ constraints (marrow, kidney), absorbed dose, and dose rate were introduced. We created a predictive calculator in the form of a free, open-source, and user-friendly spreadsheet that can be completed within minutes. Our schema achieves speed and accuracy by sampling tissue radioconcentrations (kBq/cm3) to be analyzed in conjunction with clinical input from the user that reflect dosimetric preconditions. The marrow-absorbed dose constraint was 0.217 Gy (dose rate, ≤0.0147 Gy/h) per fraction with an interfraction interval of at least 6 wk. Results: Our first 10 patients were analyzed. The first-strike mean tumor-absorbed dose threshold for any prostate-specific antigen (PSA) response was more than 10 Gy (dose rate, >0.1 Gy/h). The metastasis with the lowest first-strike tumor-absorbed dose correlated the best with the percentage decrease of PSA; its threshold to achieve hypothetical zero PSA was 20 Gy or more. Each patient's PSA doubling time can be used to personalize their unique absorbed dose-response threshold. The predicted mean first-strike prescription constrained by marrow-absorbed dose rate per fraction was 11.0 ± 4.0 GBq. Highly favorable conditions (tumor sink effect) were dosimetrically expressed as the combination of tumor-to-normal-organ ratios of more than 150 for marrow and more than 4 for kidney. Our schema obviates the traditional role of the SUV as a predictive parameter. Conclusion: Our rapid schema is feasible to implement in any busy real-world theranostics unit and exceeds today's best practice standards. Our dosimetric thresholds and predictive parameters can radiobiologically rationalize each patient's first-strike prescription down to a single becquerel. Favorable tumor-to-normal-organ ratios can be prospectively exploited by predictive dosimetry to optimize the first-strike prescription. The scientific framework of our schema may be applied to other systemic radionuclide therapies.

Prostate Specific Antigen and Prostate Cancer in Gender Affirming Hormone Therapy for Transgender or Nonbinary Individuals.

The effects of gender affirming hormone therapy on prostate specific antigen (PSA) and prostate cancer incidence in transgender or non-binary individuals (TGNB) born with prostate glands remains uncharacterized. The cohort included 1,024 self-identified TGNB individuals assigned male at birth who received PSA testing in the VA Healthcare System, matched by birth year to cisgender men. PSA changes were measuring using linear-mixed effects modeling accounting for repeated measured and matching. Non-gonadotrophin releasing hormone agonist or antagonist (GnRH) therapy was associated with 1.30 ng/mL lower PSA (95% confidence interval (CI) 1.14-1.46, p < 0.001) and GnRH therapy was associated with 1.08 ng/mL lower PSA (95% CI 0.60-1.55, p < 0.001) compared with cisgender men. Among 450 TGNB individuals who had PSA testing before and after initiation of hormone therapy, non-GnRH and GnRH therapies resulted in 0.49 ng/mL decrease (95% CI 0.35-0.62, p<0.001) and 0.73 ng/mL decrease (95% CI 0.43-1.02, p<0.001), respectively, from median baseline of 0.70 ng/mL. From time of age 50, TGNB prostate cancer incidence was 1.79 per 1,000 patient-years versus 4.02 per 1,000 patient-years in cisgender men. Gender affirming hormone therapies are associated with significant decreases in PSA, and TGNB individuals assigned male at birth remain at risk for prostate cancer. Future work should establish if a lower threshold for biopsy should be used in these contexts and if the decreased incidence is a result of ascertainment bias or hormone therapy resulting in a true decrease in the incidence of prostate cancer.

The Incidence of Extreme Serum Prostate Specific Antigen Levels During the COVID-19 Pandemic

ObjectiveThe COVID-19 pandemic resulted in decreased prostate specific antigen (PSA) testing for prostate cancer screening and its impact remains uncharacterized. Our objective was to compare incident PSA testing rates, PSA levels, and prostate cancer treatment rates before and during the pandemic after the state of emergency (SoE) was declared. Materials and MethodsThis was a population-based, retrospective cohort study among men 50-80 years of age in Ontario, Canada undergoing incident PSA testing from November 23, 2018 to July 9, 2021. Working backwards and forwards from the date of the province-wide SoE (March 17, 2020), 30-day time periods were constructed during which incident PSA testing rates were measured. Our primary outcome was the rate of incident PSA testing. Secondary endpoints included comparison of incident PSA levels and prostate cancer treatment rates. ResultsWe identified 835,402 men who underwent incident PSA testing. There was a 20% decrease in PSA testing after the SoE (RR = 0.80,95% CI: 0.800.81, P < .001). There was a higher proportion of extreme PSA levels after the SoE with a higher proportion of patients with a PSA >20 ng/mL (rate ratio = 1.63,95% CI: 1.54-1.73, P < .0001) and >100 ng/mL (rate ratio = 1.98,95% CI: 1.77-2.20, P < .0001). This effect was highest for those aged 50-59 years. More patients required active treatment (5,201,59.5% prior to the pandemic vs. 5,072,64.2%, P < .001 after the SoE declaration). ConclusionsThe COVID-19 SoE resulted in patients experiencing a 2-fold increase in the risk of having an extreme PSA level and higher odds of treatment. Future studies are needed to assess the impact on the rates of advanced prostate cancer and cancer-specific mortality.

Prostate-Specific Membrane Antigen PET/CT-Guided, Metastasis-Directed Radiotherapy for Oligometastatic Castration-Resistant Prostate Cancer.

Systemic treatments for metastatic castration-resistant prostate cancer (mCRPC) include androgen deprivation therapy, androgen receptor pathway inhibitors, chemotherapy, and radiopharmaceuticals, all of which have associated toxicity. Prostate-specific membrane antigen (PSMA) PET/CT allows for higher sensitivity in detecting metastatic disease than is possible with conventional imaging. We hypothesized that PSMA PET/CT-guided, metastasis-directed radiotherapy may offer durable disease control with low toxicity rates in patients with mCRPC who have a limited number of metastases. Methods: We retrospectively screened 5 prospective PSMA PET/CT studies for patients with mCRPC who had up to 5 sites of oligorecurrent or oligoprogressive disease on PSMA PET/CT and subsequently received definitive-intent, metastasis-directed radiotherapy to all new or progressing sites with concurrent androgen deprivation therapy. Progression-free survival, freedom from new lines of systemic therapy, and overall survival (OS) were calculated from the start of metastasis-directed radiotherapy using Kaplan-Meier analysis. Biochemical response was defined as at least a 50% decrease in prostate-specific antigen 6 mo after the start of treatment. Toxicity was graded using the Common Terminology Criteria for Adverse Events, version 5. Results: Twenty-four patients met the inclusion criteria with a median follow-up of 33.8 mo (interquartile range, 27.6-45.1 mo). Between October 2017 and April 2023, 11 patients (45.8%) had 1 treated site, 10 patients (41.7%) had 2, and 3 patients (12.5%) had 3. Five sites were prostate or prostate bed, 15 were nodal, 19 were osseous, and 1 was visceral. Seventeen patients (70.8%) continued their preexisting systemic therapy, whereas 7 (29.2%) started a new systemic therapy. Median progression-free survival was 16.4 mo (95% CI, 9.8-23.0 mo). The biochemical response rate was 66.7%. Median freedom from a new line of systemic therapy was 29.0 mo (95% CI, 7.6-50.4 mo). Median OS was not reached. The 2- and 4-y OS rates were 91.1% (95% CI, 79.3%-100%) and 68.8% (95% CI, 45.1%-92.5%), respectively. Grade 2 and grade 3 or higher toxicity rates were 4.2% and 0%, respectively. Conclusion: PSMA PET/CT-guided, metastasis-directed radiotherapy appears to offer durable disease control with low toxicity rates for oligometastatic castration-resistant prostate cancer. Further prospective studies are needed to compare metastasis-directed radiotherapy with systemic therapy versus systemic therapy alone and PSMA PET/CT-guided versus conventional imaging-guided radiotherapy.

Real-world evidence of triplet therapy efficacy in patients with metastatic castration-sensitive prostate cancer: a Japanese multicenter study.

Two randomized trials demonstrated that the survival benefits afforded by triplet therapy were greater than those of doublet therapy, thus changing the treatment paradigm for metastatic castration-sensitive prostate cancer (mCSPC). This is the first study to assess the real-world use, performance, and safety of triplet therapy in Japanese patients. This retrospective multicenter study included 45 consecutive mCSPC patients who received triplet therapy composed of androgen deprivation therapy (ADT), docetaxel, and darolutamide between January 2023 and June 2024. Baseline patient characteristics and their clinical parameters during triplet therapy were collected. Adverse events (AEs) were graded using Common Terminology Criteria for Adverse Events version 5.0, and imaging responses were evaluated following the RECIST criteria. The prostate-specific antigen (PSA) nadir was defined as the lowest PSA value during follow-up, and the PSA decrease was the initial PSA value minus the PSA nadir. The median patient age was 70years and the median follow-up duration was 10months. High-volume disease was present in 82.2% of patients. Concurrent administration of docetaxel and darolutamide was scheduled for 22.2% of cases. The incidence of any AE was 86.7%, with 55.5% of patients experiencing grade 3-4 AEs. Neutropenia was common, but prophylactic granulocyte colony-stimulating factor (G-CSF) significantly reduced the incidence of neutropenia of grade 3 or higher. Febrile neutropenia occurred in four patients (8.9%); these patients had not received prophylactic G-CSF. A decline in PSA of 90% was observed in 95.6% of patients, and an imaging response was seen in 97.8%. Triplet therapy with ADT, darolutamide, and docetaxel was highly efficacious and tolerable in Japanese mCSPC patients, particularly those with high-volume disease. Prophylactic G-CSF prescription is crucial to manage neutropenia effectively. Further studies with longer follow-ups are needed to confirm these findings and explore the long-term outcomes.

Natural history of histologically benign PIRADS 4-5 lesions in multiparametric MRI: Real-life experience in an academic center.

The follow-up findings of patients who underwent prostate biopsy for prostate image reporting and data system (PIRADS) 4 or 5 multiparametric magnetic resonance imaging (mpMRI) findings and had benign histology were retrospectively reviewed. There were 190 biopsy-naive patients. Patients with at least 12 months of follow-up between 2012 and 2023 were evaluated. All MRIs were interpreted by two very experienced uroradiologists. Of the patients, 125 had either cognitive or software fusion MR-targeted biopsies with 4 + 8/10 cores. The remaining 65 patients had in-bore biopsies with 4-5 cores. Prostate-specific antigen (PSA) levels below 4 ng/mL were defined as PSA regression following biopsy. PIRADS 1-3 lesions on new MRI images were classified as MRI regression. Median patient age and PSA were 62 (39-82) years and six (0.4-33) ng/mL, respectively, at the initial work-up. During a median follow-up period of 44 months, 37 (19.4%) patients were lost to follow-up. Of the remaining 153 patients, 82 (53.6%) had persistently high PSA. Among them, 72 (87.8%) had repeat mpMRI within 6-24 months which showed regressive findings (PIRADS 1-3) in 53 patients (73.6%) and PIRADS 4-5 index lesion persistence in 19 cases (26.4%). The latter group was recommended to have rebiopsy. Of these 19 patients, 16 underwent MRI-targeted rebiopsy. Prostate cancer was diagnosed in six (37.5%) patients and of these four (25%) were clinically significant (>Grade Group 1). Totally, clinically significant prostate cancer was detected in 4/153 (2.6%) patients followed up. Patients should be warned against the relative relaxing effect of a negative biopsy after identification of PIRADS 4-5 index lesion. While PSA decrease was observed in many patients during follow-up, persistent MRI findings were present in nearly a quarter of patients with persistently high PSA. A rebiopsy is warranted in these patients, with significant prostate cancer diagnosed in a quarter of patients with rebiopsy.

Efficacy of Enzalutamide Rechallenge for Metastatic Castration-Resistant Prostate Cancer.

There have been several reports on rechallenge with docetaxel, cabazitaxel, abiraterone acetate, or ethinylestradiol for metastatic castration-resistant prostate cancer (mCRPC). However, the efficacy of enzalutamide rechallenge for mCRPC has not been evaluated. We retrospectively reviewed 63 consecutive patients who received enzalutamide for mCRPC at our institution between 2014 and 2022. Eight of these patients underwent rechallenge with enzalutamide after disease progression on prior enzalutamide and other therapy and were the focus of this study. The prostate-specific antigen (PSA) response (PSA decrease >50%), PSA progression-free survival, treatment duration, overall survival (OS) after CRPC, and treatment-related adverse events were evaluated. PSA decline to enzalutamide rechallenge was observed in 6 patients (75%), of which 2 patients had a PSA response. The median treatment duration was 4 months (range 1-12) and median PSA progression-free survival was 3 months (range 1-7). Median OS after CRPC was 41 months. OS after CRPC was not increased in patients with a PSA response. No toxicities were worse than grade ≥3. Enzalutamide rechallenge achieved a PSA response in a quarter of our patients with mCRPC after disease progression on prior enzalutamide. However, no improvement of OS was identified in these patients.

Pluvicto in the real world setting and timing to PSA50 as a predictive marker of treatment response.

e17026 Background: Prostate cancer, the leading cause of cancer mortality in men, has seen notable advances with PSMA-targeted therapies like 177Lu-PSMA-617 (Pluvicto), particularly in the metastatic castrate resistant setting. While prostate specific antigen (PSA) serves as a useful biomarker in newly diagnosed patients or those on androgen deprivation therapy, its efficacy in monitoring patients under PSMA-directed therapy remains unclear. This underscores a critical gap: the absence of established biomarkers for tracking response to these emerging treatments. Such biomarkers are vital for enhancing patient outcomes and evaluating therapeutic efficacy in early-stage trials. Methods: In this real-world, cohort study, we retrospectively followed adult patients with metastatic, castrate-resistant prostate cancer who are treated with Pluvicto at our institution beginning January 1, 2022 through November 2023. We assessed several potential biomarkers of response temporally throughout the treatment duration of Pluvicto, including serial blood counts, chemistry profiles, PSA levels, BMI, as well as their historical treatment patterns and demographics. All patients were heavily pre-treated prior to receiving Pluvicto. By using logistic regression, we identify factors associated with treatment response. Results: In our study, 21 patients qualified for enrolment. These patients received a median of 6 treatments prior to Pluvicto. Among them, 8 (38.1%) demonstrated at least PSA50 and showed response post-treatment. Of these, 6 (75%) completed all six Pluvicto treatments, while 2 (25%) are currently undergoing treatment. Remarkably, 7 of the 8 responders (87.5%) achieved a PSA50 response after two Pluvicto doses, with all 8 (100%) reaching this marker by the third dose. Furthermore, 6 of these 8 patients (75%) exhibited a PSA90 response after the fourth dose, though 2 patients (25%) did not attain PSA90. Conclusions: Our real-world study at Scripps Clinic provides valuable insights into the efficacy of Pluvicto in treating metastatic, castrate-resistant prostate cancer. Out of 21 patients treated with Pluvicto, 38.1% exhibited a significant PSA decrease during the treatment course. Notably, 87.5% of responders achieved PSA50 before their third dose, and all responders reached this benchmark prior to their fourth dose. These findings are crucial, especially as clinical trials are exploring Pluvicto's application in earlier treatment stages. Additionally, the use of PSA50 as a biomarker could guide clinicians in timely decision-making, allowing for quicker intervention and therapy adjustments, thus potentially mitigating disease progression. Updated data to be presented.

Does enzalutamide related PSMA upregulation affect outcomes of lutetium-177 PSMA radioligand therapy?

Enzalutamide is an antiandrogen drug used prior to lutetium-177 prostate specific membrane antigen (Lu-PSMA) radioligand therapy and has shown promising results for upregulating the PSMA expression on prostate cancer cells. In this study, we aim to compare prostate specific antigen (PSA) level changes in prostate cancer patients who received enzalutamide to those who did not. Prostate cancer patients who underwent Lu-PSMA between 2021 and 2023 were retrospectively included. Patients were grouped based on prior enzalutamide therapy: those who received enzalutamide (EZ+) for at least 14 days and those who did not (EZ-). PSA changes and F-18 DCFPyL SUV (Standardized Uptake Values) were compared. Thirty-seven patients were included, 18 EZ+ and 19 EZ-. The median age, Gleason score, and prior chemo/hormonal therapies were similar for EZ+ and EZ-, except for radium-223. Eleven patients (61%) in EZ+ and 13 patients (68%) in EZ- showed a decrease in PSA after the first cycle (p = 0.64). Four patients (22%) in EZ+ and seven patients (37%) in EZ- had more than 50% decrease in PSA after the first cycle (p = 0.33). The average percent decline at the end of the treatment was 23.3% in EZ+ and 50.4% in EZ- (p = 0.4). There was no difference in terms of lesion with highest SUVmax, mean SUV, total tumor volume or activity on pre-therapy PSMA imaging. Enzalutamide treatment prior to Lu-PSMA does not improve patient outcomes when applied remotely. Larger studies evaluating the combination therapies and the timing of enzalutamide are needed to assess its correlation with Lu-PSMA outcomes.

A phase 2, single-arm trial evaluating 131 I-PSMA-1095 targeted radioligand therapy for metastatic castration-resistant prostate cancer.

Metastatic castration-resistant prostate cancer (mCRPC) remains uniformly lethal. Prostate specific membrane antigen (PSMA) is a transmembrane glycoprotein overexpressed in prostate cancer. 131 I-PSMA-1095 (also known as 131 I-MIP-1095) is a PSMA-targeted radioligand which selectively delivers therapeutic radiation to cancer cells and the tumor microenvironment. We conducted a single-arm, phase 2 trial to assess efficacy and tolerability of 131 I-PSMA-1095 in mCRPC patients who had exhausted all lines of approved therapy. All patients underwent 18 F-DCFPyL PET and 18 F-FDG PET to determine PSMA-positive tumor volume, and patients with >50% PSMA-positive tumor volume were treated with up to four doses of 131 I-PSMA-1095. The primary endpoint was the response rate of prostate specific antigen (PSA). Secondary endpoints included rates of radiographic response and adverse events. Overall and radiographic progression-free survival were also analyzed. Eleven patients were screened for inclusion and nine patients received 131 I-PSMA-1095. The median baseline PSA was 162 µg/l, and six patients demonstrated a >50% PSA decrease. One patient demonstrated a confirmed radiographic response. Median overall survival was 10.3 months, and median progression-free survival was 5.4 months. Four patients experienced adverse events of grade 3 or higher, the most frequent being thrombocytopenia and anemia. 131 I-PSMA-1095 is highly active against heavily-pretreated PSMA-positive mCRPC, significantly decreasing tumor burden as measured by PSA. Adverse events, mainly hematologic toxicity, were not infrequent, likely related to off-target irradiation. This hematologic toxicity, as well as a higher logistical burden associated with use, could represent relative disadvantages of 131 I-PSMA-1095 compared to 177 Lu-PSMA-617.

Quantification of biochemical PSA dynamics after radioligand therapy with [177Lu]Lu-PSMA-I&T using a population pharmacokinetic/pharmacodynamic model

BackgroundThere is an unmet need for prediction of treatment outcome or patient selection for [177Lu]Lu-PSMA therapy in patients with metastatic castration-resistant prostate cancer (mCRPC). Quantification of the tumor exposure–response relationship is pivotal for further treatment optimization. Therefore, a population pharmacokinetic (PK) model was developed for [177Lu]Lu-PSMA-I&T using SPECT/CT data and, subsequently, related to prostate-specific antigen (PSA) dynamics after therapy in patients with mCRPC using a pharmacokinetic/pharmacodynamic (PKPD) modelling approach.MethodsA population PK model was developed using quantitative SPECT/CT data (406 scans) of 76 patients who received multiple cycles [177Lu]Lu-PSMA-I&T (± 7.4 GBq with either two- or six-week interval). The PK model consisted of five compartments; central, salivary glands, kidneys, tumors and combined remaining tissues. Covariates (tumor volume, renal function and cycle number) were tested to explain inter-individual variability on uptake into organs and tumors. The final PK model was expanded with a PD compartment (sequential fitting approach) representing PSA dynamics during and after treatment. To explore the presence of a exposure–response relationship, individually estimated [177Lu]Lu-PSMA-I&T tumor concentrations were related to PSA changes over time.ResultsThe population PK model adequately described observed data in all compartments (based on visual inspection of goodness-of-fit plots) with adequate precision of parameters estimates (< 36.1% relative standard error (RSE)). A significant declining uptake in tumors (k14) during later cycles was identified (uptake decreased to 73%, 50% and 44% in cycle 2, 3 and 4–7, respectively, compared to cycle 1). Tumor growth (defined by PSA increase) was described with an exponential growth rate (0.000408 h−1 (14.2% RSE)). Therapy-induced PSA decrease was related to estimated tumor concentrations (MBq/L) using both a direct and delayed drug effect. The final model adequately captured individual PSA concentrations after treatment (based on goodness-of-fit plots). Simulation based on the final PKPD model showed no evident differences in response for the two different dosing regimens currently used.ConclusionsOur population PK model accurately described observed [177Lu]Lu-PSMA-I&T uptake in salivary glands, kidneys and tumors and revealed a clear declining tumor uptake over treatment cycles. The PKPD model adequately captured individual PSA observations and identified population response rates for the two dosing regimens. Hence, a PKPD modelling approach can guide prediction of treatment response and thus identify patients in whom radioligand therapy is likely to fail.

Three- and Seven-month Prostate-specific Antigen Levels as Prognostic Markers for Overall Survival in Metastatic Hormone-sensitive Prostate Cancer: Results from SWOG S1216, a Phase 3 Randomized Trial of Androgen Deprivation Plus Orteronel or Bicalutamide

BackgroundA robust decrease in prostate-specific antigen (PSA) in response to androgen deprivation therapy (ADT) has been evaluated as a prognostic factor in patients with metastatic hormone-sensitive prostate cancer (mHSPC) since 2006, but the treatment of mHSPC has since evolved to include intensified therapy. ObjectiveWe assessed the association of PSA levels at 3 (PSA-3mo) and 7 (PSA-7mo) mo with overall survival (OS) in patients with mHSPC treated with ADT combined with either bicalutamide or orteronel in the S1216 phase 3 clinical trial. Design, setting, and participantsPSA responses to treatment of patients in the S1216 trial were categorized as: complete response (CR) if PSA was ≤0.2 ng/ml, partial response if PSA was >0.2 and ≤4 ng/ml, and no response (NR) if PSA was >4 ng/ml. Outcome measurements and statistical analysisA Cox analysis (adjusted for treatment arm and three stratification factors: performance status, severity of disease, and early vs late induction) was used for OS association. While PSA-7mo association was a prespecified objective, PSA-3mo association was also evaluated. Results and limitationsA total of 1251 and 1231 patients from the S1216 study were evaluable for PSA-3mo and PSA-7mo, respectively. A PSA-7mo CR was associated with improved OS compared with NR (HR: 0.20; p < 0.0001). A PSA-3mo CR showed a similar association to NR (HR: 0.34; p < 0.0001). The association of a PSA response with survival did not differ by treatment arm at either time point. ConclusionsThe PSA-3mo and PSA-7mo responses were strongly associated with OS; taken with other emerging prognostic biomarkers, these markers may allow for early identification of patients at the highest risk of death, aid with counseling in clinical practice, and permit design of future clinical trials targeting these patients. Patient summaryA low prostate-specific antigen level at 3 or 7 mo after starting treatment for metastatic hormone-sensitive prostate cancer predicts longer survival regardless of the first treatment given with androgen deprivation therapy.

Early change in apparent diffusion coefficient as a predictor of response to neoadjuvant androgen deprivation and external beam radiation therapy for intermediate- to high-risk prostate cancer

To determine the role of serial apparent diffusion coefficient (ADC) as a biomarker for response to neoadjuvant androgen deprivation therapy (nADT) followed by external beam radiation therapy (EBRT) in intermediate- to high-risk prostate cancer (PCa) patients. This Health Insurance Portability and Accountability Act (HIPAA)-compliant, institutional review board (IRB)-approved prospective study included 12 patients with intermediate- to high-risk PCa patients prior to nADT and EBRT, who underwent serial serum prostate-specific antigen (PSA) and multiparametric prostate magnetic resonance imaging (mpMRI) at baseline (BL), 8-weeks after nADT initiation (time point [TP]1), 6-weeks into EBRT delivery (TP2), and 6-months after nADT initiation (TP3). Tumour volume (tVOL) and tumour and normal tissue ADC (tADC and nlADC) were determined at all TPs. tADC and nlADC dynamics were correlated with post-treatment PSA using Pearson's correlation coefficient. Paired t-tests compared pre/post-treatment ADC. There was a sequential decrease in PSA at all TPs, reaching their lowest values at TP3 post-treatment completion. Mean tADC increased significantly from baseline to TP1 (917.8±107.7×10-6 versus 1033.8±139.3×10-6 mm2/s; p<0.01), with no subsequent change at TP2 or TP3. Both percentage and absolute change in tADC from BL to TP1 correlated with post-treatment PSA (r=-0.666, r=-0.674; p=0.02). Post-treatment PSA in good responders (<0.1 ng/ml) versus poor responders (≥ 0.1 ng/ml) was associated with a greater increase in tADC from BL to TP1 (169.2±122.4×10-6 versus 22.9±75.5×10-6 mm2/s, p=0.03). This pilot study demonstrates the potential for early ADC metrics as a biomarker of response to nADT and EBRT in intermediate to high-risk PCA.

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.

Angiotensin II Receptor Blockers Cause Changes in Prostate-specific Antigen Levels: A Retrospective Cohort Study.

We previously reported a decrease in prostate-specific antigen (PSA) levels in patients with castration-resistant prostate cancer treated with angiotensin II receptor blockers (ARBs). However, no studies have reported the effect of ARBs on PSA variability in patients without a history of prostate cancer. Therefore, we conducted a population-based, retrospective study to determine whether ARBs have an inhibitory effect on elevated PSA levels in Japanese patients without a history of prostate cancer. This study was conducted using a large-scale Japanese claim database, including male patients aged ≥60 years who had two or more PSA measurements with an interval between measurements of 3 months to 2 years between April 2008 and June 2019. Patients who had been prescribed ARBs were grouped into the ARB group, and those who were prescribed antihypertensive drugs other than ARBs were grouped into the non-ARB group. We compared the proportions of patients with second PSA levels greater than the first. The numbers of eligible patients in the ARB and non-ARB groups were 777 and 527, respectively. Multivariate logistic regression analysis revealed that the proportion of patients with elevated PSA levels was significantly lower in the ARB group than in the non-ARB group (adjusted odds ratio=0.80, 95% confidence interval=0.64-0.99, p=0.047). ARBs may suppress elevated PSA levels in patients without a history of prostate cancer. This contributes to the prevention of prostate cancer.

External beam radiotherapy in treatment of high-volume metastatic hormone-sensitive prostate cancer: clinical case

The standard treatment for metastatic hormone-sensitive prostate cancer does not include external beam radiotherapy (EBRT) and radionuclide therapy with radium-223.The article describes a clinical case of successful use of EBRT and radionuclide therapy with radium-223 in a patient with primary high-volume metastatic hormone-sensitive prostate cancer.The patient received diagnosis of prostate cancer сT3bN1M1b (Gleason score 8 (4 + 4)), stage IV (metastases in the bones, extraperitoneal and intrathoracic lymph nodes; prostate specific antigen (PSA) level was 4280 ng/mL). Between October of 2017 and January of 2018, the patient received 6 cycles of chemohormonal therapy (degarelix + docetaxel). Bilateral orchiectomy was performed on 05.02.2018, and the patient underwent palliative EBRT on cervical vertebrae between 04.10.2017 and 19.10.2017 with total dose of 32.6 Gy (equivalent to 38.5 Gy). The patient received systemic radiotherapy with one injection of samarium oxabifor (153Sm) 40 mCi (21.03.2018) and radium-223 (4 injections once a month (17.04.2018, 15.05.2018, 14.06.2018, 10.07.2018) + 2 injections 1 time per 3 months (October 2018, January 2019)). Partial response was achieved in the form of PSA decrease from 4280 ng/mL (September 2017) to 0.505 ng/mL (May 2019). Palliative EBRT for the prostate and pelvis was performed between 14.11.2018 and 19.12.2018 for total dose of 62.5 Gy (equivalent to 69 Gy). For 2 years remission was observed with PSA level of 0.3–0.5 ng/mL. In December of 2020, biochemical recurrence was diagnosed: PSA level increased from 0.61 ng/mL in October to 1.43 ng/mL on 28.12.2020. The second course of radionuclide therapy with radium-223 5,500 MBq/mL was performed (22.01.2021, 05.03.2021, 02.04.2021) with increase of PSA level to 1.92 ng/mL (May of 2021) and independent decrease to 0.542 ng/mL (June of 2022). In December of 2022, biochemical recurrence was observed with a small increase of PSA level to 1.67 ng/mL. Currently, the disease is stabilized.

Feasibility of apalutamide combined with androgen deprivation therapy and short-course low-dose prednisone in treating metastatic hormone-sensitive prostate cancer: a pilot randomized controlled trial.

The role of prednisone in the prevention of androgen receptor antagonist-related rash and treatment for metastatic hormone-sensitive prostate cancer (mHSPC) is unclear. This pilot trial (ChiCTR2200060388) aimed to investigate the feasibility of apalutamide combined with androgen deprivation therapy (ADT) and short-course low-dose prednisone in the treatment of mHSPC. All patients received apalutamide and ADT and were randomly divided into two groups based on the administration of oral prednisone or not (control group). The primary endpoint was the incidence of rash. The secondary endpoint included the proportions of patients with a decline in PSA ≥50% from baseline, PSA ≥90% from baseline, and decreased to PSA ≤0.2 ng/mL. Between June 2021 and March 2022, a total of 83 patients were enrolled (41 in the prednisone group and 42 in the control group). During the 6-month follow-up, the incidence of rash was significantly lower in the prednisone group compared with the control group (17.1% vs. 38.1%, P=0.049). There were no significant differences in the incidence of other adverse events, the number of patients who required dose adjustment (reduction, interruption, or discontinuation) of apalutamide due to rash, the number of patients with prostate-specific antigen (PSA) decreased by ≥50%, the number of patients with PSA decrease ≥90%, and the number of patients with PSA ≤0.2 ng/mL between the two groups. All patients with diabetes had stable glycemic control with no glucose-related adverse events. In patients with mHSPC, the addition of short-course low-dose prednisolone to apalutamide plus ADT can reduce the incidence of rash without risk of other adverse events.