Prostate-specific Antigen Response Research Articles

Analysis of Molecular Imaging and Laboratory Baseline Biomarkers in PSMA-RLT: Whole-Body Total Lesion PSMA (TLP) Predicts Overall Survival.

The aim of this retrospective study was to identify pre-therapeutic predictive laboratory and molecular imaging biomarkers for response and overall survival (OS) in patients with metastatic castration-resistant prostate cancer (mCRPC) treated with prostate-specific membrane antigen (PSMA)-targeted radioligand therapy (RLT). Pre-therapeutic laboratory and [68Ga]Ga-PSMA-11 PET/CT data of n = 102 mCRPC patients receiving [177Lu]Lu-PSMA-617 RLT within a prospective registry (REALITY Study, NCT04833517) were analyzed including laboratory parameters such as alkaline phosphatase (ALP), prostate-specific antigen (PSA), gamma glutamyl transferase (GGT), glutamate oxaloacetate transaminase (GOT), glutamate pyruvate transaminase (GPT), neuron specific enolase (NSE), hemoglobin (Hb), and imaging parameters such as maximum standardized uptake value of the tumor lesions (SUVmax), the mean standardized uptake value of all tumor lesions (SUVmean), the whole-body molecular tumor volume (MTV), and the whole-body total lesion PSMA (TLP). Mann-Whitney U test, univariate and multivariable Cox-regression were performed to test for association of the parameters with response and OS. The SUVmean of all lesions was significantly different between responders and non-responders (SUVmean responders 8.95 ± 2.83 vs. non-responders 7.88 ± 4.46, p = 0.003), whereas all other tested biochemical and imaging parameters did not reveal significant differences. Hb and the molecular imaging parameters MTV and TLP showed a significant association with OS (p = 0.013, p = 0.005; p = 0.009) in univariant Cox regression; however, only TLP remained significant in multivariable analysis (Hazard ratio 1.033, p = 0.009). This study demonstrates a statistically significant association between the quantitative PET/CT imaging parameter SUVmean and PSA response, as well as between the baseline TLP and OS of mCRPC patients undergoing RLT.

Early Prostate-Specific Antigen Response by 6 Months Is Predictive of Treatment Effect in Metastatic Hormone Sensitive Prostate Cancer: An Exploratory Analysis of the TITAN Trial.

Early PSA response has been found to be prognostic of outcomes in metastatic hormone sensitive prostate cancer. We performed a secondary analysis of the TITAN trial to determine if early PSA response was predictive of treatment efficacy in metastatic hormone sensitive prostate cancer patients. Early PSA response was defined as achieving a PSA level of ≤ 0.2 ng/mL by 6 months of random assignment. A Cox proportional hazard model was constructed in a landmark population with an interaction term between the treatment and early PSA response to determine differential treatment effect on overall survival (OS). We applied multivariable Cox proportional hazard regression model with time to early PSA response fitted with restricted cubic spline to determine the association of time to early PSA response with OS. Approximately 24% (124/524) of patients in the androgen deprivation therapy (ADT) alone group and 61% (321/524) in the apalutamide group had PSA response ≤ 0.2 ng/mL by 6 months. Longer time to early PSA response was associated with significantly superior OS in the apalutamide group. There was a significant difference in treatment effect from apalutamide on OS (P = .03 for interaction) among 6-month PSA responders (HR: 0.66; 95% CI: 0.44-1.00) vs nonresponders (HR: 1.14; 95% CI: 0.89-1.46). This difference in treatment effect was not statistically significant at 3 months (P = .17 for interaction). Among 6-month PSA responders, 3-year confounder-adjusted OS was 84% (80%-88%) for the apalutamide group and 74% (66%-82%) for the ADT alone group. Among nonresponders, 3-year adjusted OS for the 2 treatment arms were 58% (52%-65%) and 56% (51%-60%), respectively. Early PSA response by 6 months was a predictor of treatment efficacy from ADT plus apalutamide on OS. Longer time to early PSA response was associated with superior OS in the apalutamide arm.

Efficacy and safety of rechallenge [177Lu]Lu-PSMA-617 RLT after initial partial remission in patients with mCRPC: evaluation of a prospective registry (REALITY study)

AimRechallenge of [177Lu]Lu-PSMA-617 radioligand therapy (RLT) was proposed for patients who initially responded to PSMA-RLT experiencing partial remission, but relapsed into progression after a certain period of remission. However, only limited data is available regarding this approach. In this study, we analyzed the efficacy and safety profile of one or more series of [177Lu]Lu-PSMA-617 RLT rechallenge in patients from a prospective registry (REALITY Study, NCT 04833517) after they initially benefited from PSMA-RLT.MethodsForty-seven patients with metastatic castration-resistant prostate cancer (mCRPC) who had biochemical response to initial [177Lu]Lu-PSMA-617 RLT followed by disease progression received at least one (up to three) series of [177Lu]Lu-PSMA-617 RLT rechallenge. Biochemical response rates based on prostate-specific antigen (PSA) serum value, PSA-based progression-free survival (PFS) and overall survival (OS) were calculated. Adverse events of the treatment were assessed according to ‘common terminology criteria for adverse events’ (CTCAE).ResultsAfter one series of RLT rechallenge, a PSA decline of at least 50% was achieved in 27/47 patients (57.4%). The median PFS of all patients was 8.7 mo and the median OS was 22.7 mo, each calculated from the administration of the first rechallenge series. Patients who responded (PSA decline > 50%) to the rechallenge showed a median OS of 27.3 mo. Regarding PFS, a significant correlation (r = 0.4128, p = 0.0323) was found for these patients comparing initial and rechallenge RLT. Ten patients received a second and 3 patients received a third rechallenge series with 8/10 and 3/3 patients responding to repeated RLT rechallenge. No severe deterioration of adverse events rated by CTCAE criteria was observed.Conclusion[177Lu]Lu-PSMA-617 RLT rechallenge is associated with significant PSA response and encouraging survival outcome as well as a very favourable safety profile and should therefore be considered as a straight-forward treatment option in mCRPC patients, who previously benefited from PSMA-RLT.

Acute Toxicity and Early Prostate Specific Antigen Response After Two-Fraction Stereotactic Radiation Therapy for Localized Prostate Cancer Using Peri-Rectal Spacing – Initial Report of the SABR-Dual Trial

Purpose: SABR-Dual is a phase III trial with an initial phase-I safety cohort, of two-fraction stereotactic radiotherapy (SABR) with optional MRI-based focal boost, using peri-rectal spacing, for localized prostate cancer. This represents the initial report from the phase-I non-randomized cohort. Materials and methods: Subjects had favorable intermediate risk (FIR) or low risk (LR) prostate adenocarcinoma, and gland volume <80cc. All underwent radiopaque hydrogel spacer and fiducial marker placement prior to simulation (CT and 3-tesla T2 MRI). The clinical target volume included the entire prostate, and in FIR patients, 1-2cm of seminal vesicle (SV). A 2mm expansion was applied for planning target volume (PTV), and a dose of 27 Gy was prescribed to the PTV-prostate, 23 Gy to the PTV-SV, with an optional 30 Gy simultaneous boost (SIB) to an MRI-defined dominant lesion. Primary endpoint was 3-month patient-reported changes in quality of life based on the EPIC-26, IPSS, and SHIM questionnaires. Secondary endpoints were 6-month quality of life, acute toxicity (using CTCAEv5) and early PSA response. Results: Among the 20 patients in the phase-I cohort, 95% had FIR disease, and 50% received an SIB. At median follow-up of 8 months, a 3-month minimally clinically important change occurred in 1/20 (5%), 6/20 (30%), 2/20 (10%), 4/20 (20%), and 5/20 (25%) in urinary incontinence, urinary obstructive, bowel, sexual, and hormonal domains. There was a mean increase of 1±5.4 in IPSS and decrease of 1.8±6.5 in SHIM scores. Rates of grade 2 urinary and bowel toxicity 10% and 0%, respectively, with no grade ≥3 toxicities. Mean PSA decrease at last follow-up was 70.4%±17.7%. Conclusion: This generalizable protocol of two-fraction prostate SABR using peri-rectal spacing is a safe approach for ultra-hypofractionated dose-escalation, with minimal acute toxicity. Longer-term outcomes and direct comparison with standard 5-fraction SABR are being studied in the phase-III randomized portion of SABR-Dual.

Abiraterone Acetate Versus Enzalutamide Against Chemo-Naïve Castration-Resistant Prostate Cancer With Full-Dose Induction.

Purpose We recently released the multi-institutional real-world analysis about the difference in survival outcomes between abiraterone acetate and enzalutamide against chemo-naïve castration-resistant prostate cancer (CRPC) in a first-line setting. Although reduced dose induction cases were included in that analysis, induction dose reduction might correlate with reduced efficacy. In this study, we analyzed full-dose induction subgroups from our overall cohort and investigated the true difference in efficacy between these agents. Methods A total of 220 chemotherapy-naïve CRPC cases treated with full-dose induction of first-line androgen receptor signaling inhibitor (ARSI) were analyzed. Outcome measures were prostate-specific antigen (PSA) response, PSA progression-free survival (PSA-PFS), treatment failure-free survival (TFF), cancer-specific survival (CSS), and overall survival (OS). Results Abiraterone acetateand enzalutamide were administered to 58 and 162 patients, respectively. The median PSA response rate (-65.4% (A) and -81.5% (E), p = 0.0252), PSA decline ≥ 90% (22.4% (A) and 37.0% (E), p = 0.0478), PSA-PFS (median four months (A) and seven months (E), p = 0.00833), TFF (median six months (A) and 15 months (E), p<0.0001), CSS (median 45 months (A) and not reached (E), p < 0.0001), and OS (median 34 months (A) and 80 months (E), p<0.001) were significantly better in the E group. Conclusion This study showed that PSA response, PSA-PFS, TTF, CSS, and OS were better with first-line enzalutamide administration. Direct inhibition of androgen receptor signaling by enzalutamide is associated with better clinical outcomes in the full-dose induction cohort.

Impact of proton pump inhibitors on the efficacy of androgen receptor signaling inhibitors in metastatic castration-resistant prostate cancer patients.

Proton pump inhibitors (PPIs) are widely used due to their affordability and minimal severe side effects. However, their influence on the efficacy of cancer treatments, particularly androgen receptor signaling inhibitors (ARSIs), remains unclear. This study investigates the impact of PPI usage on the treatment outcomes in patients with metastatic castration-resistant prostate cancer (mCRPC). A total of 117 mCRPC patients were retrospectively analyzed and divided into two groups based on the concomitant use of PPI at the initiation of ARSI treatment: PPI+ (n = 38) and PPI- (n = 79). Patient characteristics, including age at ARSI treatment administered, prostate-specific antigen (PSA) value at ARSI treatment administered, International Society of Urological Pathology grade group at prostate biopsy, metastatic site at ARSI treatment administered, prior docetaxel (DTX) treatment, and type of ARSI (abiraterone acetate or enzalutamide) were recorded. Progression-free survival (PFS), overall survival (OS), and PSA response rates were compared between the two groups. Patients were further stratified by clinical background to compare PFS and OS between the two groups. The PPI- group exhibited significantly extended PFS and a trend toward improved OS. For PSA response (reduction of 50% or more from baseline), the rates were 62.3% and 45.9% in the PPI- group and the PPI+ group, respectively. For deep PSA response (reductions of 90% or more from baseline), the rates were 36.4% and 24.3% in the PPI- group and the PPI+ group, respectively. The effects were consistent across subgroups divided by prior DTX treatment and type of ARSI administered. The administration of PPIs appears to diminish the therapeutic efficacy of ARSIs in mCRPC patients. Further prospective studies are needed to confirm these findings and explore the biological mechanisms involved.

Analysis of the immune-inflammatory indices for patients with metastatic hormone-sensitive and castration-resistant prostate cancer

BackgroundInflammation plays a pivotal role in the progression of prostate cancer (PCa). Several immune-inflammatory indices, including neutrophil to lymphocyte ratio (NLR), derived neutrophil to lymphocyte ratio (dNLR), lymphocyte to monocyte ratio (LMR) and platelet to lymphocyte ratio (PLR), lung immune prognostic index (LIPI), systemic inflammation response index (SIRI) and systemic immune inflammation index (SII), have demonstrated their prognostic values in several solid malignancies. However, Comparisons of superiority with these seven indices’ predictive efficacy within metastatic hormone-sensitive PCa (mHSPC) and metastatic castration-resistant PCa (mCRPC) remain uncertain.MethodsWe retrospectively included 407 patients diagnosed with mHSPC and 158 patients with mCRPC at West China Hospital from 2005 to 2022. The seven immune-inflammatory indices were computed based on hematological data of mHSPC at initial diagnosis and mCRPC at progression to CRPC. Prognostic value for castration-resistant prostate cancer-free survival (CFS), overall survival (OS), prostate-specific antigen progression-free survival (PSA-PFS) and prostate-specific antigen (PSA) response was assessed using Kaplan–Meier curves, Cox regression models, and chi-square tests. The predictive performance of each immune-inflammatory index was assessed using the area under the curve (AUC) in time-dependent receiver operating characteristic curve (ROC) analysis and C-index calculation.ResultsAll seven immune-inflammatory indices were significantly associated with CFS and OS in the mHSPC cohort, as well as with PSA response, PSA-PFS, and OS in the mCRPC cohort. In the mHSPC cohort, LIPI consistently exhibited higher AUC values compared to NLR, dNLR, LMR, PLR, SII, and SIRI for predicting CFS and OS. This indicates that LIPI had a superior discriminative ability compared to the other indices (C-index of LIPI: 0.643 and 0.686 for CFS and OS, respectively). Notably, the predictive advantage of LIPI over other indices in the mHSPC stage diminished in the mCRPC stage.ConclusionsThis study firstly confirmed the prognostic value of SII, SIRI and LIPI in mHSPC and mCRPC, and revealed that LIPI had a higher predictive power than NLR, dNLR, LMR, PLR, SII and SIRI in mHSPC. These non-invasive indices can enable clinicians to quickly assess the prognosis of patients.

Bone Pain and Survival Among Patients With Metastatic, Hormone-Sensitive Prostate Cancer

The presence of bone pain is significantly associated with worse overall survival (OS) in patients with castration-resistant prostate cancer. However, there are few data regarding bone pain and survival outcomes in the context of metastatic, hormone-sensitive prostate cancer (MHSPC). To compare survival outcomes among patients with MHSPC by presence or absence of baseline bone pain at diagnosis. This post hoc secondary analysis, conducted from September 1 to December 31, 2023, used patient-level data from SWOG-1216, a phase 3, prospective randomized clinical trial that enrolled patients with newly diagnosed MHSPC from 248 academic and community centers across the US from March 1, 2013, to July 15, 2017. All patients in the intention-to-treat population who had available bone pain status were eligible and included in this secondary analysis. In the SWOG-1216 trial, patients were randomized (1:1) to receive either androgen deprivation therapy (ADT) with orteronel, 300 mg orally twice daily (experimental group), or ADT with bicalutamide, 50 mg orally daily (control group), until disease progression, unacceptable toxic effects, or patient withdrawal. Overall survival was the primary end point; progression-free survival (PFS) and prostate-specific antigen (PSA) response were secondary end points. Cox proportional hazards regression models were used for both univariable and multivariable analyses adjusting for age, treatment type, Gleason score, disease volume, Zubrod performance status, and PSA level. Of the 1279 male study participants, 301 (23.5%) had baseline bone pain at MHSPC diagnosis and 896 (70.1%) did not. Bone pain status was unavailable in 82 patients (6.4%). The median age of the 1197 patients eligible and included in this secondary analysis was 67.6 years (IQR, 61.8-73.6 years). Compared with patients who did not experience bone pain, those with baseline bone pain were younger (median age, 66.0 [IQR, 60.1-73.4] years vs 68.2 [IQR, 62.4-73.7] years; P = .02) and had a higher incidence of high-volume disease (212 [70.4%] vs 373 [41.6%]; P < .001). After adjustment, bone pain was associated with shorter PFS and OS. At a median follow-up of 4.0 years (IQR, 2.5-5.4 years), patients with bone pain had median PFS of 1.3 years (95% CI, 1.1-1.7 years) vs 3.7 years (95% CI, 3.3-4.2 years) in patients without initial bone pain (adjusted hazard ratio [AHR], 1.46; 95% CI, 1.22-1.74; P < .001) and OS of 3.9 years (95% CI, 3.3-4.8 years) vs not reached (NR) (95% CI, 6.6 years to NR) in patients without initial bone pain (AHR, 1.66; 95% CI, 1.34-2.05; P < .001). In this post hoc secondary analysis of the SWOG-1216 randomized clinical trial, patients with baseline bone pain at MHSPC diagnosis had worse survival outcomes than those without bone pain. These data suggest prioritizing these patients for enrollment in clinical trials, may aid patient counseling, and indicate that the inclusion of bone pain in prognostic models of MHSPC may be warranted. ClinicalTrials.gov Identifier: NCT01809691.

Do Indian men have similar oncological outcomes with abiraterone plus androgen deprivation therapy in the setting of metastatic hormone-sensitive prostate cancer? A prospective observational study.

Combination of abiraterone with androgen deprivation therapy (ADT) has better survival outcomes than ADT alone in metastatic Hormone-sensitive prostate cancer (mHSPC) in the Western population. In this prospective (Clinical Trials Registry-India [CTRI] registered) observational study, we present the comparative oncological outcomes of ADT alone and ADT + abiraterone in Indian patients, which is not available currently. This study (CTRI-number-CTRI/2020/07/026545) included newly diagnosed mHSPC patients from January 2020 to June 2023 in a tertiary care hospital, urology department. Patients fulfilling inclusion criteria were advised ADT with abiraterone (A + ADT), and those not affording received ADT monotherapy (ADT). The primary endpoint was overall survival (OS). Secondary outcomes included prostate-specific antigen (PSA) decline >90%, radiographic progression-free survival (rPFS), and PSA progression-free survival (pPFS). Out of 278 patients with mHSPC, 163 patients were excluded and 115 were analyzed (ADT = 40 vs. A + ADT = 75). After a median follow-up of 20.3 months, 11 of 40 (27.5%) in ADT-only arm and 15 of 75 (20%) in ADT + abiraterone arm had died (Hazard-ratio of death 0.72; 95% confidence interval 0.68-0.88; P < 0.001). A PSA decline of >90% was seen in 85% in the ADT alone group and 93.3% in the ADT + abiraterone group. Significantly better outcomes of the ADT + abiraterone were seen in the secondary endpoints of rPFS (P < 0.001) and pPFS (P < 0.001). The OS benefit was 28% reduction in risk of death in our study versus 37% and 38% in STAMPEDE and LATITUDE, respectively. pPFS and rPFS were also poorer in Indian subsets. Abiraterone with ADT improves OS, PSA response, rPFS, and pPFS in the Indian population akin to the Western data but with poorer OS, rPFS, and PSA progression-free survival on comparison.

Gleason Pattern 5 May Be a Prognostic Factor in Radium-223 Treatment.

Radium-223 treatment reduces the risk of death in patients with metastatic castration-resistant prostate cancer (CRPC). This study analyzed the prognostic factors in patients treated with radium-223 dichloride. Patients who received radium-223 dichloride were retrospectively analyzed. Prostate-specific antigen (PSA) response and alkaline phosphatase (ALP) decline rates were analyzed. Overall survival (OS) was evaluated using Kaplan-Meier curves, and prognostic factors for OS were assessed using Cox proportional hazards analysis. Fifty-six patients were included in the study. The five-year OS rate in patients after diagnosis of CRPC was 62.2% [95% confidence interval (CI)=27.55-112.45], while the five-year OS rate in patients at the initiation of radium-223 treatment was 21.3% (95%CI=17.20-36.79). Six patients (11.1%) had a >50% PSA decline rate, and 10 (17.9%) had a >50% ALP decline rate. Cox proportional hazards analysis showed that PSA levels at the initiation of radium-223 treatment [hazard ratio (HR)=1.00; 95%CI=1.00-1.00; p=0.0054] and Gleason Pattern (GP) 5 (HR=5.42; 95%CI=1.08-27.27; p=0.0400) were associated with OS. Patients with GP 5 had a significantly poorer prognosis compared with patients with a GP ≤4. Early administration of radium-223 as a first- or second-line treatment was not associated with OS compared with late administration of radium-223 as a third-line or later treatment. GP 5 and high PSA levels at radium-223 initiation were associated with worse OS. Radium-223 as first- or second-line treatment was not associated with OS. Therefore, a treatment strategy for CRPC based on GP 5 is needed.

Clinical Outcomes and Risk Stratification in Patients With Metastatic Hormone-Sensitive Prostate Cancer Treated With New-Generation Androgen Receptor Signaling Inhibitors

BackgroundOptimal drug selection for metastatic hormone-sensitive prostate cancer (mHSPC) remains unclear. We therefore assessed the clinical outcomes of mHSPC treated with new-generation androgen receptor pathway inhibitors (ARSIs) and identified risk factors associated with the prognosis of mHSPC. MethodsWe retrospectively reviewed 324 patients with mHSPC who were treated with ARSIs, including abiraterone acetate, enzalutamide, and apalutamide, between January 2018 and December 2022. In addition to assessing the prostate-specific antigen (PSA) response and overall survival (OS) during ARSI treatment, we investigated several potential risk factors for a poor OS in patients with mHSPC. ResultsPatients with a ≥ 90% PSA reduction (hazard ratio [HR]: 0.24, 95% confidence interval [CI], 0.10-0.58; P = .002) and those whose PSA declined to ≤ 0.2 ng/mL (HR: 0.22, 95% CI, 0.08-0.63; P = .005) showed significantly better OS than other patients. Gleason grade group 5 (GG5), presence of liver metastasis, and an LDH ≥ 250 U/L were identified as prognostic factors significantly associated with a poor OS, with HRs of 2.31 (95% CI, 1.02-5.20; P = .044), 7.87 (95% CI, 2.61-23.8; P < .001) and 3.21 (95% CI, 1.43-7.23; P = .005). ConclusionWe identified GG5, the presence of liver metastasis, and elevated LDH at the diagnosis as significant factors predicting the OS of mHSPC, but the choice of ARSIs did not affect the prognosis. The potential prognostic impact of these markers requires further investigation.

Real‑world retrospective study of early‑stage prostate cancer at a Portuguese Comprehensive Cancer Centre: The PEarlC study.

Despite the high prevalence of localised prostate cancer (LPC) and locally advanced prostate cancer (LAPC), evidence on the characteristics of patients, treatments and clinical outcomes stratified by disease risk is limited. The PEarlC study was conducted to characterise a cohort of patients with early-stage prostate cancer that included real-world clinical outcomes. Retrospective data from a cohort of patients diagnosed with LPC/LAPC between 2015 and 2017 and followed up until December 2020 at a Portuguese comprehensive cancer centre (IPO Porto) was analysed. Patients were classified as LPC (high- or non-high-risk) or LAPC according to European Association of Urology guidelines, were eligible if diagnosed at stage I-III and followed up in Urology, Medical Oncology or Radiation Oncology outpatient clinics of IPO Porto. Data was collected from the medical/administrative records database. Clinical outcomes included prostate-specific antigen (PSA) progression-free survival, metastasis-free survival, disease-free survival, progression-free survival, overall survival (OS), PSA response (palliative) and no evidence of residual tumour (prostatectomy). Time-to-event outcomes were compared between subgroups using the log-rank test. A total of 790 patients were included (54.8% non-high-risk LPC, 30.9% high-risk LPC, 14.3% LAPC) and the median follow-up was 46.7 months. Patients had a median age of 68.0 years. The majority of patients were stage II (52.9%) and Eastern Cooperative Oncology Group 0-1 (99.9%) and received treatment with curative intent (85.4%). The median was only achieved in progression-free survival (29.9 months; 95% CI, 26.5-41.0 months), as evaluated in palliative patients. At year 5, 82.9% were free of PSA progression (curative), 87.5% were metastasis-free, 83.7% were disease-free, all patients in palliative treatment progressed and the 5-year OS rate was 92.9% (CI 95%, 90.2-95.7%). Among patients with LPC, OS was worse in high-risk vs. non-high-risk patients (5-year OS rate, 88.8% vs. 96.8%; hazard ratio=3.34, CI 95%, 1.64-7.05; P=0.001). PSA response rate was 81.4% in the palliative setting. There was no evidence of residual tumour in 61.6% of patients who underwent prostatectomy. Although most patients with early-stage prostate cancer treated at IPO Porto showed positive 5-year real-world outcomes, patients with high-risk LPC showed worse OS compared with patients with non-high-risk LPC and therefore a poorer prognosis. The present large-sample real-world study is an important contribution to reducing the evidence gap on prostate cancer.

Deescalated 225Ac-PSMA-617 Versus 177Lu/225Ac-PSMA-617 Cocktail Therapy: A Single-Center Retrospective Analysis of 233 Patients.

The aim of this work is to evaluate our clinical real-world data obtained with 225Ac-PSMA-617 (AcPSMA), which were acquired under compassionate care regulations in patients with advanced-stage prostate cancer. The objective parameters that could be derived from this evaluation are compared with previous literature about AcPSMA and 177Lu-PSMA-617 (LuPSMA). Methods: The medical files of all patients who had received AcPSMA on an individual patient basis at the Heidelberg University Hospital since January 2014 were analyzed retrospectively. Previously published patients were excluded. The remaining patients were tailored into 2 subgroups with different treatment strategies: group 1 received AcPSMA as a deescalated monotherapy, and group 2 received LuPSMA plus AcPSMA as a cocktail regimen. Baseline characteristics, serum prostate-specific antigen (PSA) response, and overall survival were compared with the most appropriate historical controls. Results: Of 287 patients treated, 54 were excluded because of previous publication and 233 were evaluated, 104 of whom received AcPSMA monotherapy (median, 6 MBq). In this group, 55 patients (53%) presented with a best PSA response of at least 50%. The other 129 patients received a cocktail therapy of AcPSMA (median, 4 MBq) plus LuPSMA (4 GBq). In this group, a best PSA response of at least 50% was observed in 74 patients (57%). The median overall survival in the monogroup was 9 mo and in the cocktail group was 15 mo. If adjusted for prognostic baseline characteristics, the efficacy of both regimens was not significantly different. Conclusion: Deescalated treatment activities of AcPSMA or AcPSMA and LuPSMA cocktail regimens present better tolerability with regard to xerostomia than previous regimens of at least 100 kBq/kg while retaining high antitumor activity in poor-prognosis prostate cancer patients.

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.

Utidelone for heavily pretreated metastatic castration-resistant prostate cancer after failing docetaxel treatment: An open-label, single-arm, phase II trial.

e17036 Background: The appropriate chemotherapy for metastatic castration-resistant prostate cancer (mCRPC) that progressed after docetaxel treatment remains unmet medical needs. Utidelone (UTD1) is a genetically engineered epothilone analog with antitumor activity in taxane-resistant cancers. UTD1 was approved for advanced breast cancer in 2021. This study was designed to evaluate the safety and efficacy of UTD1 in mCRPC. Methods: In this perspective, phase II clinical trial, men with progressive mCRPC after docetaxel and abiraterone, and/or enzalutamide, and/or apalutamide received UTD1 monotherapy treatment at a total dose of 150 mg/m2 for five days intravenous, every three weeks until disease progression, or intolerable toxicity, or death. We reported the preliminary results for potential benefits in this new treatment. The primary endpoint was prostate specific antigen (PSA) response rate, defined as a 50% or greater reduction in serum PSA. The secondary endpoint included investigators-assessed objective response rate (ORR) and disease control rate (DCR) according to RECIST v1.1, radiographic progression-free survival (rPFS) according to PCWG3 criteria, overall survival (OS), and safety. The trial was registered at Chinese Clinical Trial Registry (No. ChiCTR2200061635). Results: By January 31st, 2024, twenty-five mCRPC patients with a median age of 67 years were enrolled in this study at Sun Yat-sen University Cancer Center since March 23rd, 2022. Patients received an average of 4.2 lines of prior anticancer treatments: 100% of them received docetaxel, 96.0% of them received abiraterone, and 80.0% progressed after enzalutamide, and/or apalutamide. 28.0% of patients had visceral metastases, and 88.0% patients had bone metastases. At of the cut-off date, the PSA response rate was 16.0%. The median rPFS and OS were 4.9 months and 7.1 months, respectively. One patient had a durable response for 19.2 months and had been remaining on study treatment to date. One PR and four SD were observed in ten patients with measurable lesions, resulting in an overall ORR and DCR of 10.0% and 50.0%, respectively. The most common treatment-related adverse events (TRAEs) including peripheral sensory neuropathy (76.0%), dyspepsia (72.0%), anemia (64.0%), constipation (60.0%), fatigue (64.0%), nausea (36.0%), leukocytopenia (32.0%), arthralgia (32.0%), dizziness (32.0%), vomiting (20.0%), and diarrhea (20.0%) were manageable. The 3/4 grade TRAEs included anemia (16.0%), and diarrhea (4%). No treatment-related death occurred. Conclusions: UTD1 has demonstrated promising efficacy and favorable tolerance in heavily pretreated mCRPC patients after progression on docetaxel in the preliminary analyses. Additional randomized trials are warranted for this new regimen. Clinical trial information: ChiCTR2200061635.

Pembrolizumab plus Abiraterone Acetate and Prednisone in Patients with Chemotherapy-naïve Metastatic Castration-resistant Prostate Cancer: Results from KEYNOTE-365 Cohort D

Background and objectiveAbiraterone acetate (abiraterone) plus prednisone is approved for the treatment of metastatic castration-resistant prostate cancer (mCRPC). Our aim was to evaluate the efficacy and safety of pembrolizumab plus abiraterone in mCRPC. MethodsIn cohort D of the phase 1b/2 KEYNOTE-365 study (NCT02861573), patients were chemotherapy-naïve, had disease progression ≤6 mo before screening, and had either not received prior next-generation hormonal agents for mCRPC or had received prior enzalutamide for mCRPC and had disease progression or became intolerant to enzalutamide. Patients received pembrolizumab 200 mg intravenously every 3 wk plus abiraterone 1000 mg orally once daily and prednisone 5 mg orally twice daily. The primary endpoints were safety, prostate-specific antigen (PSA) response rate, and objective response rate (ORR) according to Response Evaluation Criteria in Solid Tumors version 1.1 (RECIST v1.1) by blinded independent central review (BICR). Secondary endpoints included radiographic progression-free survival (rPFS) according to Prostate Cancer Clinical Trials Working Group 3–modified RECIST v1.1 by BICR and overall survival (OS). Key findings and limitationsFor the 103 patients who were treated, median follow-up was 28 mo (interquartile range 26–31). The confirmed PSA response rate was 56% (58/103 patients). The ORR for patients with RECIST v1.1–measurable disease was 16% (6/37 patients). Median rPFS was 15 mo (95% confidence interval 9.2–22) and median OS was 30 mo (95% confidence interval 23–not reached); the estimated 24-mo OS rate was 58%. In total, 91% of patients experienced treatment-related adverse events, and 39% experienced grade 3–5 events. Grade 3/4 elevation of alanine aminotransferase (ALT) or aspartate aminotransferase (AST) was observed in 12% and 6.8% of patients, respectively. One patient died due to treatment-related myasthenic syndrome. Study limitations include the single-arm design. ConclusionsPembrolizumab plus abiraterone and prednisone demonstrated antitumor activity and acceptable safety in patients with chemotherapy-naïve mCRPC. Higher incidence of grade 3/4 elevated ALT/AST occurred than was reported for the individual agents. Patient summaryFor patients with metastatic castratation-resistant prostate cancer, the drug combination of pembrolizumab plus abiraterone and prednisone showed antitumor activity and acceptable safety.

A phase 1/2, first-in-human, open-label, dose-escalation study of TAK-280, an investigational B7-H3 x CD3ε conditional bispecific redirected activation (COBRA) T-cell engager, in adult patients with unresectable, locally advanced, or metastatic solid tumors.

TPS2684 Background: TAK-280 is a novel COBRA T-cell engager that targets the B7 homolog 3 protein (B7-H3), an antigen highly expressed in a range of solid tumors including metastatic castration-resistant prostate cancer (mCRPC) and non–small cell lung cancer. In its prodrug form, TAK-280 binds to B7-H3, but not to CD3ε. Once in the protease-rich tumor microenvironment, TAK-280 undergoes protease-mediated activation through formation of CD3ε-binding active dimers, which stimulate CD3 T-cell activation and cytotoxic antitumor response against co-engaged B7-H3–expressing cells. In preclinical studies, TAK-280 demonstrated cleavage-dependent conditionality, engagement of tumor target antigen, and induction of T-cell mediated tumor killing. TAK-280 has the potential to target solid tumors that are not amenable to treatment with conventional first- or second-generation T-cell engagers, while limiting toxicity to normal tissues. Methods: This phase 1/2 study is enrolling adult patients with unresectable, locally advanced, or metastatic solid tumors described in the literature to have enhanced B7-H3 expression, who are ineligible or intolerant to standard therapies. Other eligibility criteria include Eastern Cooperative Oncology Group performance status ≤1 and measurable disease per RECIST v1.1. Key exclusion criteria include history of autoimmune disease, major surgery ≤8 weeks before first dose of TAK-280, and history of clinically significant cardiac or gastrointestinal disorders. During phase 1 dose escalation, TAK-280 is administered as an intravenous infusion, once weekly, in 28-day cycles at a pre-defined dose level range. Patients who do not experience dose-limiting or other unacceptable toxicities may receive up to 14 treatment cycles depending on response; patients are treated until disease progression, unacceptable toxicity, or withdrawal from study. The dose-escalation phase will determine two recommended doses for expansion to be assessed during the cohort-expansion phase. The primary endpoint is incidence of dose-limiting or other toxicities during dose escalation; secondary endpoints include pharmacokinetic parameters, response assessment per RECIST v1.1, overall response rate, duration of response, progression-free survival, overall survival, disease control rate, and prostate-specific antigen response in patients with mCRPC. Cytokine release syndrome is closely managed and reported per American Society for Transplantation and Cellular Therapy consensus grading. Approximately 182 patients are planned to be enrolled (42 in dose escalation and 100–142 in cohort-expansion); as of the data cutoff date of Jan 10, 2024, 18 patients have received the study drug. Clinical trial information: NCT05220098 .

Androgen Receptor Splice Variant 7 in Asian Patients With Metastatic Castration-Resistant Prostate Cancer.

Androgen receptor splice variant 7 (ARV-7) is a resistance mechanism to hormonal therapy in metastatic castrate-resistant prostate cancer (mCRPC). It has been associated with poor outcomes. On progression to castrate resistance, ARV-7 positivity has been identified in global populations at an incidence of 17.8%-28.8%. Here, we characterize the incidence of ARV-7 positivity in Asian patients with mCRPC in a prospective fashion and evaluate its implications on treatment outcomes. Patients with mCRPC from multiple centers in Southeast and East Asia were enrolled in a prospective manner before initiation of androgen receptor signaling inhibitors or docetaxel. ARV-7 status was evaluated at baseline with three commercially available assays: AdnaTest Prostate Cancer platform, Clearbridge method, and IBN method. Clinical outcomes at progression were assessed. The primary end point of this study was prevalence of ARV-7 positivity; secondary end points were incidence of ARV-7 positivity, prostate specific antigen (PSA) response rate, PSA progression-free survival (PFS), and overall survival (OS). A total of 102 patients with a median age of 72 years at enrollment participated. Overall, an incidence of ARV-7 positivity of between 14.3% and 33.7% in Asian patients with mCRPC was demonstrated depending on the assay used. Patients found to have ARV-7 positivity at enrollment had a numerically worse PSA PFS compared with ARV-7 negative patients. In this study, the incidence of ARV-7 positivity in Asian patients with mCRPC was shown to be similar to the global population. Patients with ARV-7 positivity appear to have more aggressive disease with numerically worse PSA PFS and OS. Further prospective studies are needed to fully characterize the relationship that ARV-7 positivity has on prognosis of Asian patients with mCRPC.

Docetaxel plus cis-platinum chemotherapy for the posterior line treatment of metastatic castrate-resistant prostate cancer with elevated neuron specific enolase.

e17042 Background: This Study is to figure out the efficacy of docetaxel plus cis-platinum (DC) chemotherapy as the posterior line treatment for metastatic castrate-resistant prostate cancer (mCRPC) with elevated neuron specific enolase (NSE). Methods: We performed a retrospective study of men suffered mCRPC with elevated NSE from December 2019 to August 2022. All men were treated with DC after resistance to previous therapy. Biochemical progression-free survival (BPFS) were depicted using Kaplan-Meier curves. Results: 10 mCRPC patients aged 65.8 ± 7.0 (Median: 66.5, Range: 52-77) received DC for 1 to 10 cycles (Median: 7). Of the 10 patients, 2, 1 and 7 patients underwent DC as the 2nd, 3rd and 4th line therapy, respectively. 3 patients received previous chemotherapy and 9 patients underwent new endocrine therapy. All patients suffered bone metastases, 6 patients suffered distal lymph node metastases and 3 patients suffered visceral metastases. 6.1 ± 2.8 cycles (Median: 7, Range: 1-10) of DC were finished. Median follow-up time was 6.5 (Range: 2-11) months. After DC, Prostate specific antigen (PSA) response rate (&gt;50%) was 90% and NSE response rate (&gt;50%) was 60%. Median BPFS was 10 (Range: 4-18) months. Pain score declined from 6.6 ± 3.1 to 3.9 ± 2.4 evidently (P &lt; 0.05) and Karnofsky (KPS) score increased from 80 ± 14.9 to 91 ± 16.0 significantly (P &lt; 0.05). Of the 6 patients assessed by radiological examinations, 5 patients experienced partial response and 1patient achieved stable disease. Conclusions: Our pilot study showed docetaxel plus cis-platinum chemotherapy was effective for the mCRPC patients with elevated NSE resistant to multi-line therapies, indicating the potential value of DC for mCRPC with neuroendocrine differentiation.

Comparison of prostate-specific antigen (PSA) response in patients with de novo metastatic castration-sensitive prostate cancer (mCSPC) treated with apalutamide (APA) vs abiraterone acetate (ABI): A real-world (RW) causal analysis.

Comparison of prostate-specific antigen (PSA) response in patients with de novo metastatic castration-sensitive prostate cancer (mCSPC) treated with apalutamide (APA) vs abiraterone acetate (ABI): A real-world (RW) causal analysis.