Citations

AbstractCurrent US clinical practice guidelines for advanced prostate cancer management contain recommendations based on high‐level evidence from randomized controlled trials; however, these guidelines do not address the nuanced clinical questions that are unanswered by prospective trials but nonetheless encountered in day‐to‐day practice. To address these practical questions, the 2024 US Prostate Cancer Conference (USPCC 2024) was created to generate US‐focused expert clinical decision‐making guidance for circumstances in which level 1 evidence is lacking. At the second annual USPCC meeting (USPCC 2024), a multidisciplinary panel of experts convened to discuss ongoing clinical challenges related to 5 topic areas: biochemical recurrence; metastatic, castration‐sensitive prostate cancer; poly [ADP‐ribose] polymerase inhibitors; prostate‐specific membrane antigen radioligand therapy; and metastatic, castration‐resistant prostate cancer. Through a modified Delphi process, 34 consensus recommendations were developed and are intended to provide clinicians who manage prostate cancer with guidance related to the implementation of novel treatments and technologies. In this report, the authors review the areas of consensus identified by the USPCC 2024 experts and evaluate ongoing unmet needs regarding translational application of the current clinical evidence.

Abstract Purpose: Metastatic castration-resistant prostate cancer (mCRPC) resistant to androgen receptor signaling inhibitors (ARSI) is often lethal. Liquid biopsy biomarkers for this deadly form of disease remain under investigation, and underpinning mechanisms remain ill-understood. Experimental Design: We applied targeted cell-free DNA (cfDNA) sequencing to 126 patients with mCRPC from three academic cancer centers and separately performed genome-wide cfDNA methylation sequencing on 43 plasma samples collected prior to the initiation of first-line ARSI treatment. To analyze the genome-wide sequencing data, we performed nucleosome positioning and differential methylated region analysis. We additionally analyzed single-cell and bulk RNA sequencing data from 14 and 80 patients with mCRPC, respectively, to develop and validate a stem-like signature, which we inferred from cfDNA. Results: Targeted cfDNA sequencing detected AR/enhancer alterations prior to first-line ARSIs that correlated with significantly worse progression-free survival (P = 0.01; HR = 2.12) and overall survival (P = 0.02; HR = 2.48). Plasma methylome analysis revealed that AR/enhancer lethal mCRPC patients have significantly higher promoter-level hypomethylation than AR/enhancer wild-type mCRPC patients (P < 0.0001). Moreover, gene ontology and CytoTRACE analysis of nucleosomally more accessible transcription factors in cfDNA revealed enrichment for stemness-associated transcription factors in patients with lethal mCRPC. The resulting stemness signature was then validated in a completely held-out cohort of 80 patients with mCRPC profiled by tumor RNA sequencing. Conclusions: We analyzed a total of 220 patients with mCRPC, validated the importance of cell-free AR/enhancer alterations as a prognostic biomarker in lethal mCRPC, and showed that the underlying mechanism for lethality involves reprogramming developmental states toward increased stemness. See related commentary by Nawfal et al., p. 7

e17040 Background: Our aim was to evaluate two distinct clinical settings catering to US patients with metastatic castration-resistant prostate cancer (mCRPC): academic (A) and community (C) practice. We used data from a real-world non-interventional study (REASSURE; NCT02141438) examining the use of 223Ra. Methods: Patients with mCRPC who received at least one dose of 223Ra in the US were included. Enrolment occurred between 2014 and 2017; median follow-up was nearly 12 months. Our analysis included patient disease characteristics, treatment history, short- and long-term safety of 223Ra, patient overall survival (OS), and patient-reported pain (Brief Pain Inventory – Short Form [BPI–SF] scores). A clinically meaningful pain response was a ≥2-point decrease from a baseline score of ≥2 in the BPI-SF worst pain item during treatment until last dose. Results: Analysis included 498 patients (A: 147; C: 351). Comparing A with C, the median ages were 70 and 76 years, respectively, and the majority of patients (74% and 84%) had bone-only metastases. A higher percentage of patients in A (69%) than in C (49%) had completed at least one life-prolonging therapy (LPT) prior to 223Ra; these included abiraterone (A: 38%; C: 19%), enzalutamide (A: 32%; C:17%), docetaxel (A: 38%; C: 19%), and sipuleucel-T (A: 18%; C: 25%). Most patients received 5–6 223Ra injections in both settings (A: 65%; C: 71%). 223Ra was used concomitantly with LPTs in 48% of patients in A and 57% in C, predominantly with abiraterone (A: 25%; C: 25%) or enzalutamide (A: 25%; C: 36%); fewer patients in A (35%) received concomitant bone health agents than in C (52%). For safety outcomes, refer to the table. During treatment, 47% and 62% of patients with a baseline BPI-SF ≥2 had a clinically meaningful pain response in A and C, respectively. The median OS was 17.2 months (95% CI 14.0–19.4) in A and 18.4 months (14.8–21.0) in C. More patients in A (42%) than in C (26%) received a LPT after 223Ra, most commonly docetaxel (A: 25%; C: 12%). Conclusions: Patients treated in A tended to be younger and more heavily treated, as evidenced by a higher number of patients receiving LPTs prior to and following 223Ra treatment. Bone health agents were more frequently used in C. Additionally, more patients in C had a clinically meaningful pain response and more drug-related AEs were reported in A. Despite the observed differences, overall survival was comparable for both practice settings. Clinical trial information: NCT02141438 . [Table: see text]

3020 Background: Radioligand therapy (RLT) use has been increasing with the approval of 177Lu-Dotatate for metastatic neuroendocrine tumors (NET) & 177Lu-PSMA-617 for metastatic castration resistant prostate cancer (mCRPC). Therapy-related myeloid neoplasms [tMN, including myelodysplastic syndrome (MDS) & acute myeloid leukemia, (AML)] have been reported after 177Lutetium (177Lu) for NET with rates of 2-20% & median time from first 177Lu to tMN of 2.8yrs [4-12]. Clonal hematopoiesis (CH) is a risk factor for tMN, with the spectrum of CH depending on selection pressures. To describe the prevalence of therapy selected CH & tMN, we performed a retrospective analysis of patients (pts) who had a bone marrow biopsy (BMB) post-177Lu. Methods: After IRB approval, we queried the electronic health record for pts with BMB post-177Lu. Pt demographics, treatment history, labs & BMB results were collected. Results: Fifty-seven pts met criteria, 41 (72%) with NET & 16 (28%) with mCRPC. . Median age at BMB was 68yrs (range, 28-85). Of the 57pts, prior treatments included: radiation (RT) in 21 (37%), temozolomide in 14 (25%), taxane in 15 (26%), & platinum agents in 10 (18%). The median number of 177Lu cycles was 4 (range, 1-11).Cytogenetics were available in 84% (n = 48) & were normal in 60% (n = 29). Of those with abnormal cytogenetics (n = 18, 38%), the most common abnormalities involved chromosome (chr) 7 (n = 12, 26%), chr 5 (n = 7, 15%), chr 20 (n = 5, 11%) and complex karyotypes in 7 (15%), with 3 (17%) of these patients having no mutations. Diagnoses were assessable in 49 (86%) pts: 15 (31%) with undefined cytopeniasand 16 (33%) with tMDS. Metastatic carcinoma was identified in 17 Fifty-one percent (n = 29), at a median of 0.5yrs (range, 0.04-2.6) after hematologic diagnosis. Conclusions: The enrichment of CH involving the DDR pathway in recipients of 177Lu underscores the impact of RLT on bone marrow progenitors.

AbstractBackground[177Lu]Lu–PSMA‐617 (177Lu‐PSMA‐617) plus protocol‐permitted standard of care (SOC) prolonged overall survival (OS) and radiographic progression‐free survival (rPFS) versus SOC in patients with prostate‐specific membrane antigen (PSMA)–positive metastatic castration‐resistant prostate cancer (mCRPC) in the phase 3 VISION study, in addition to beneficial effects on symptomatic skeletal events (SSEs) and health‐related quality of life (HRQOL).MethodsPost hoc analyses used the full analysis set from the VISION study (N = 831) overall and by randomized treatment arm (177Lu‐PSMA‐617 plus SOC, n = 551; SOC, n = 280). Correlations were determined between OS and rPFS and between rPFS or OS and time to SSE or to worsening HRQOL (Functional Assessment of Cancer Therapy–Prostate [FACT‐P] and 5‐level EQ‐5D [EQ‐5D‐5L]). Correlation analyses used an iterative multiple imputation copula‐based approach (correlation coefficients [rho] of <0.3 were defined as weak, ≥0.3 and <0.5 as mild, ≥0.5 and <0.7 as moderate, and ≥0.7 as strong).ResultsIn the overall population, rPFS correlated strongly with OS (rho, ≥0.7). Correlations between rPFS or OS and time to SSE without death were weak or mild. Time to worsening in the FACT‐P total score and emotional and physical well‐being domains correlated mildly or moderately with rPFS and moderately with OS. Correlation coefficients for time‐to‐worsening EQ‐5D‐5L scores were mild to moderate for both rPFS and OS. Correlation coefficients were similar between treatment arms.ConclusionsIn this analysis of the VISION study, rPFS correlated strongly with OS but not with time to SSE or worsening HRQOL. These findings require further investigation.

12079 Background: Many troublesome symptoms experienced by men with prostate cancer are not specific to a particular disease state or treatment modality. As such, these issues' scope is neither fully appreciated nor characterized in the reporting of clinical trial data. A modern accounting of poorly controlled symptoms is needed to better inform survivorship and supportive care efforts. Methods: Data are drawn from the Enhanced, EHR-facilitated Cancer Symptom Control (E2C2) study, a cluster-randomized stepped wedge trial examining the effectiveness of routine symptom assessment and management on patient-centered outcomes and healthcare utilization (NCT03892967). This is a population-level study supporting patients with cancer, who are cared for in medical oncology clinics across the Midwest United States. The trial utilizes an automated symptom monitoring system with EHR-enabled algorithms for symptom triage and intervention. The current analysis focuses on pre-intervention surveys. The cohort includes E2C2 participants with prostate cancer (as determined by the Mayo Clinic Cancer Registry) receiving curative or palliative-intent therapies, along with prostate cancer survivors who previously completed their treatment. The prevalence of SPPADE symptoms (sleep disturbance, pain, impaired physical function, anxiety, depression, fatigue [low energy]) was assessed using 0 to 10 numerical rating scales (NRS), with scores of 4-6 indicating moderate symptoms and 7-10 indicating severe symptoms. Results: A total of 1,388 men with prostate cancer completed a pre-intervention survey between March 2019 and January 2023. The median age at completion of first survey was 74 years. The cohort includes patients living in diverse settings, including urban (n=718, 52%), micropolitan (n=250, 18%), small town (n=218, 16%), and rural (n=200, 14%) environments. The proportion of patients experiencing moderate-to-severe symptoms (NRS score ≥4) was 47% for fatigue, 40% for impaired physical function, 32% for sleep disturbance, 27% for pain, 22% for anxiety, and 20% for depression/emotional distress. The three domains with the highest prevalence of severe symptoms (NRS score ≥7) were fatigue (17%), impaired physical function (12%), and sleep disturbance (10%). Conclusions: Proactive symptom monitoring identifies a high overall burden of moderate-to-severe symptoms, particularly fatigue and impaired physical function, among prostate cancer patients and survivors. Collaborative care approaches and symptom control trials are needed to mitigate and manage these burdensome symptoms. Clinical trial information: NCT03892967 . [Table: see text]

TPS5125 Background: B7-H3 is a member of the B7 superfamily, which includes PD-L1 (B7-H1) and PD-L2 (B7-DC). Enoblituzumab is a humanized Fc-optimized B7-H3–targeting antibody that induces antibody-dependent cellular cytotoxicity (ADCC). A recent investigator-initiated trial demonstrated that enoblituzumab therapy, used in the neoadjuvant prostate cancer setting, is feasible, safe, may enhance short-term clinical outcomes, and appears to stimulate intratumoral immune activation including CD8+ T cell infiltration and peripheral expansion of tumor-infiltrating T-cell clones that correlated with undetectable PSA at 1-year post-prostatectomy. To assess the impact of enoblituzumab on recurrence-free survival following prostatectomy, a phase 2, randomized, neoadjuvant clinical trial in high-risk localized prostate cancer patients has been started. We hypothesize that targeting B7-H3 with enoblituzumab will delay or prevent recurrence following prostatectomy compared to standard of care (SOC) . Methods: The HEAT trial is an investigator-initiated, multi-center, randomized, phase 2 study that is presently enrolling (NCT06014255). Eligible patients will undergo a pre-treatment prostate biopsy and conventional imaging (CT and bone scan) as well as PSMA-PET. Patients who have clinical stage cT1c-T3b, cN0 cM0 disease by conventional imaging (N1 by PSMA allowed with up to 3 LNs each ≤1 cm) will be eligible as long as concurrent hormonal or radiation therapy is not given. Prostate biopsy, within 3 months of enrollment, needs to show at least 3 positive cores containing at least 1 core with at least 50% disease involvement with Gleason ≥4+3=7 disease (with at least 1 additional high-risk feature such as PSA>20 ng/ml or cT3) or a Gleason sum ≥8. Patients will receive enoblituzumab at a dose of 15mg/kg IV biweekly for 6 doses (12 weeks) on the treatment arm, followed by prostatectomy, or will be scheduled for prostatectomy directly within 4-8 weeks on the SOC arm. 219 patients will be randomized (2:1) to treatment versus SOC. Pre-treatment, on-treatment, and post-treatment biomarkers of response and resistance will be collected. Patients will be followed according to standard institutional practices, but will require PSA evaluations every 3 (±1) months during year 1 and every 6 (±2) months during years 2-5. In both arms, salvage or adjuvant therapy will occur after biochemical or radiographic progression. The primary endpoint is recurrence-free survival (RFS) defined as any metastasis events, local pelvic visceral or lymph node recurrence, detectable prostate-specific antigen (PSA), or start of subsequent local or systemic therapy (including salvage or adjuvant therapy), or death for any cause, whichever occurs first. Secondary endpoints include additional clinical and immunologic correlates. Clinical trial information: NCT06014255 .

TPS5116 Background: Prostate cancer (PC) is common and despite recent advances in treatment options, patients with metastatic disease still have poor outcomes, warranting the development of new effective therapies in this setting. Prostate-specific membrane antigen (PSMA) is expressed in benign and malignant prostate tissues and luminal surface of salivary/lacrimal glands, small intestine and renal tubules. The double PSMA binding moiety of SAR-bisPSMA in 64Cu-SAR-bisPSMA (imaging) and 67Cu-SAR-bisPSMA (therapy) may offer advantages compared to currently used single-target PSMA agents. Clinical evidence demonstrated 2-3 times higher uptake of 64Cu-SAR-bisPSMA compared to the single-target PSMA agent, 68Ga-PSMA-11. Pre-clinical efficacy data of 67Cu-SAR-bisPSMA in mice showed statistically significant tumor growth inhibition compared to the control group as well as a dose-dependent delay in eventual tumor regression in a PC xenograft study. These results led to the development of this clinical study, which aims to assess safety and anti-tumor efficacy of 67Cu-SAR-bisPSMA in patients with metastatic castrate resistant PC (mCRPC). Methods: SECuRE is a phase I/IIa multi-center, open-label, non-randomized, dose-escalation and cohort expansion study of 64Cu-SAR-bisPSMA and 67Cu-SAR-bisPSMA (NCT04868604). mCRPC patients with progression, prior exposure to at least one androgen receptor pathway inhibitor, and positive 64Cu-SAR-bisPSMA PET may be treated with 67Cu-SAR-bisPSMA. This study is being conducted in 3 phases: a 64Cu-SAR-bisPSMA Dosimetry Phase (n=6), a 67Cu-SAR-bisPSMA Dose Escalation Phase (n=up to 24), and a 67Cu-SAR-bisPSMA Cohort Expansion Phase (n=14). The primary and key secondary objectives include assessment of 64Cu- and 67Cu-SAR-bisPSMA safety and dosimetry, determining the maximum tolerated dose (MTD) or maximum feasible dose (MFD) and anti-tumor efficacy of 67Cu-SAR-bisPSMA. The 67Cu-SAR-bisPSMA dose levels investigated in the escalation phase include: 4 GBq (cohort 1, single dose), 8 GBq (cohort 2, single dose), 12 GBq (cohort 3, single dose) and up to 24 GBq across two doses (cohort 4, two doses at MTD or MFD). The Dose Expansion Phase of the study will allow the administration of up to 4 doses of 67Cu-SAR-bisPSMA at the MTD/MFD. Response measurements include reduction in PSA levels, radiological progression-free survival, duration of response and overall survival. Radiological response will be assessed by RECIST V1.1 and PCWG3. At the time of submission of this abstract, no dose limiting toxicities have been observed to date in the first 3 cohorts. In the United States, 4 sites are active with additional sites in planning. Additional sites in the US and Australia are currently in start-up. Clinical trial information: NCT04868604 .

TPS5115 Background: The treatment of advanced prostate cancer (PC) is challenging, with no curative therapy to date and undesirable side effects that may impact patient quality of life. Monoclonal antibodies enable high specificity with low rates of off-target organ exposure, prolonged retention in PSMA+ tumors, and a predictable safety profile. There is a strong rationale for further investigation of the 177Lu-labeled, chelator-conjugated antibody, 177Lu-DOTA-rosopatamab (hereafter, TLX591), with prior studies demonstrating a favorable safety profile and efficacy, particularly with a fractionated (dose-dense) regimen Phase 1 ProstACT SELECT preliminary results demonstrate consistent uptake between TLX591 and 68Ga-PSMA-11 imaging and reinforces advantages of this first-in-class radio-antibody drug conjugate investigational therapy. Methods: In this multinational, multicenter, prospective, randomized, open label phase 3 study, patients (N=400) with PSMA-expressing metastatic castration-resistant PC (mCRPC) that have progressed despite prior treatment with an androgen-receptor pathway inhibitor (ARPI) will be enrolled in a 2:1 ratio to receive best protocol-defined standard of care (SoC) with or without 2 intravenous injections of 2.8 GBq of TLX591, given 14 days apart. SoC may be alternative ARPI or docetaxel. Eligible patients must have received 1 prior ARPI in the mCSPC, nmCRPC, or 1L mCRPC setting. Patients must have 150x109 /L platelets, and have PSMA-positive disease on 68Ga-PSMA-11 PET/CT imaging. The primary endpoint is radiographic progression-free survival. Secondary endpoints include 5-year overall survival, tumor objective response rate, time to symptomatic skeletal event, health-related quality of life, and treatment-related adverse events count. An alpha control and 95% confidence intervals will be used; patients will be substratified between TLX591 + 2nd ARPI or TLX591 + docetaxel. This study is currently enrolling. This study is funded by Telix Pharmaceuticals. Clinical trial information: NCT04876651 .

e17061 Background: ThePhase 3 VISION trial demonstrated that [177Lu]Lu-PSMA-617 prolonged overall survival (OS) in metastatic-castration resistant prostate cancer (mCRPC) patients who progressed on taxane-based chemotherapy and androgen receptor-signaling inhibitors (ARSi). The expanded access program (EAP) (NCT04825652) was opened to provide access to [177Lu]Lu-PSMA-617 for eligible patients until regulatory approval was obtained. The VISION trial required strict inclusion and exclusion criteria, which may not represent the patient population encountered in clinical practice. This study aimed to evaluate the efficacy and safety profile of [177Lu]Lu-PSMA-617 in a real-world setting within the EAP and compare the results with those from the VISION trial. Methods: Patients enrolled in the EAP between May 2021 and March 2022 at four institutions in the United States with available toxicity and outcome data were included. Outcome measures included overall survival (OS), ≥50% PSA decline rates (PSA-RR), and incidences of toxicity according to Common Terminology Criteria for Adverse Events (CTCAE) v5.0. Differences in baseline characteristics, toxicity, and PSA-RR between the EAP and VISION were evaluated using a t-test of proportions. Results: 117 patients with mCRPC were eligible and included. Patients enrolled in the EAP were similarly pretreated with taxane-based chemotherapy regimens (>1 taxane: 47% vs 40%; p=0.16) and more heavily pretreated with ARSi (>1 ARSi: 70% vs 46%; p<0.001). EAP patients had similar levels of ≥3 grade anemia (18% vs 13%; p=0.15), thrombocytopenia (13% vs 8%; p=0.13), and neutropenia (3% vs 3%; p=0.85) and higher levels of ≥3 grade lymphopenia (34% vs 8%; p<0.001). Patients treated within the EAP experienced numerically shorter OS (median OS: 13.7 vs 15.3 months) and similar PSA-RR (40% vs 46%; p=0.29). Median follow-up was numerically shorter in the EAP compared with VISION (14.7 mo vs 20.3 mo). Conclusions: mCRPC patients treated with [177Lu]Lu-PSMA-617 in a real-world setting were more heavily pretreated with ARSi, had a similar safety profile, and experienced numerically shorter OS and similar PSA-RR compared with VISION trial patients. A major limitation of this study is that we did not have access to individual patient data from the VISION trial, so we were not able to assess whether differences in OS between VISION and the EAP were statistically significant.