Citations

TPS898 Background: Enfortumab vedotin with pembrolizumab (EV/Pembro) is now first-line therapy for locally advanced or metastatic urothelial carcinoma (la/mUC) following the EV-302/KEYNOTE-A39 trial, which demonstrated a 67.7% response rate and prolonged survival. However, ~35% of cancers exhibited primary resistance and most responders relapse within one year, with post-EV/Pembro therapies achieving < 15% response and median survival < 3 years. We previously showed that therapeutic plasma exchange (TPE) removed soluble PD-L1 and other immune checkpoint inhibitor (ICI) blocking soluble factors from the blood and that this overcame ICI resistance. Combining TPE with EV/Pembro rechallenge may overcome acquired resistance and restore antitumor immunity. Methods: RECIPE-B1 [NCT07087860] is an open-label, randomized phase II trial enrolling 50 patients (1:1) with EV/Pembro-refractory la/mUC and ECOG 0–2. Arm A receives TPE on days 1–3 followed by EV 1.25 mg/kg IV plus pembrolizumab 200 mg IV on day 3 of each 21-day cycle for the first three cycles, then continues EV/Pembro alone from cycle 4. Arm B receives investigator’s-choice next-line standard of care (SOC) per NCCN guidelines. Tumor assessments occur at the end of cycle 4 (±28 days) and every 12 weeks thereafter; safety is monitored each cycle (CTCAE v5.0). The primary endpoint is objective response rate (ORR) by RECIST 1.1, comparing TPE + EV/pembro versus SOC. Secondary endpoints include progression-free survival, overall survival, duration of response, quality of life (EORTC QLQ-CIPN20), and safety. Correlative studies evaluate circulating and urinary tumor DNA and exosomal biomarkers (including exosomal Nectin-4) as predictors of response and resistance. The trial is open at Mayo Clinic; as of September 2025, 2 of 50 patients have been enrolled, with planned accrual of ~2 patients/month and central coordination at Mayo Clinic and affiliates. Clinical trial information: NCT07087860 .

TPS892 Background: Enfortumab Vedotin (EV) plus pembrolizumab (Pembro) is now first-line therapy for advanced urothelial carcinoma (UC), yielding ~30% complete response (CR) rates; nevertheless, most patients (pts) progress within 1 year and median overall survival (OS) remains < 3 years. In muscle invasive bladder cancer, local consolidation after systemic therapy improves outcomes, suggesting that residual, treatment-refractory intravesical disease drives relapse. We hypothesize that cytoreductive cystectomy/nephroureterectomy (CC/U)—with metastasis-directed therapy (MDT) as needed—can consolidate responses to EV/Pembro and extend benefit in regionally advanced or metastatic UC. CAST-AI prospectively evaluates this multimodal strategy and integrates correlative studies of exosomal Nectin-4 and circulating tumor DNA (ctDNA) from blood and urine as predictive/MRD biomarkers. Methods: CAST-AI is a phase II, decentralized single-arm trial enrolling pts with histologically confirmed UC of the bladder or upper urinary tract with ≥N1 and/or M1 disease and ECOG PS 0–2 who are potential surgical candidates (planned n = 75). Treatment: EV 1.25 mg/kg IV D1 & D8 + Pembro 200 mg IV D1 q21d, ≥4 cycles; MDT permitted any time pre-surgery. Response assessments occur q9 weeks (±4) to 18 months, then q12 weeks (±4). Surgical eligibility requires: (A) fitness for surgery; (B) complete or partial response (CR/PR) or, for select low-burden/unmeasurable disease, urologist-adjudicated candidacy; (C) all distant sites addressed; and (D) procedure in pt’s best interest. Post-CC/U maintenance EV/Pembro is encouraged per clinical discretion and guided by definitive surgical pathology results, which provide true pathologic staging often unattainable through imaging after systemic therapy. Primary endpoint: 12-month progression-free survival (PFS). Secondary endpoints: Objective response rate (ORR), CR rate, down-staging at CC/U, PFS, OS, and safety (using CTCAE). Exploratory endpoints: longitudinal exosomal Nectin-4 and ctDNA dynamics as MRD and early relapse indicators; tissue–blood–urine Nectin-4 concordance; pt-reported tolerability (using CIPN20). Key exclusions: > 20% variant histology or disallowed subtypes (e.g., micropapillary, plasmacytoid, sarcomatoid, neuroendocrine); prior chemotherapy for UC; contraindications to surgery/EV/ICI; or active uncontrolled comorbidities/infections. Status: Enrollment is open and ongoing, with 25 of 75 pts enrolled as of September 2025. The trial uses a decentralized model, allowing pts to receive EV/Pembro at their local facility, with central coordination, biospecimen shipping, and surgical evaluation at Mayo Clinic or affiliated sites. ClinicalTrials.gov: NCT06764095. Clinical trial information: NCT06764095 .

TPS283 Background: Emerging evidence suggests that metastasis-directed therapy (MDT) with stereotactic body radiotherapy (SBRT) can delay systemic therapy in oligometastatic castration-sensitive prostate cancer (omCSPC). However, the optimal timing of androgen deprivation therapy (ADT) and androgen receptor pathway inhibitor (ARPI) initiation in this setting remains undefined. While deferred ADT following MDT may preserve quality of life, early short-course ADT/ARPI may eradicate micrometastatic disease and extend progression-free survival. Extracellular vesicles (EVs) carrying PSMA-positive prostate cancer (PC) signals and circulating tumor DNA (ctDNA) may serve as real-time biomarkers of MRD and treatment response. Methods: DIVINE [NCT06378866] is an open-label, phase II, randomized trial enrolling men with omCSPC defined by 1–5 metastases (≥1 extrapelvic) on conventional imaging (CT/MRI and bone scan) and testosterone >100 ng/dL. PSMA PET may be obtained for correlative purposes but does not determine eligibility. Participants (N = 220) are randomized 1:1 to: Arm A (Early systemic): SBRT plus 6 months of ADT + ARPI. Arm B (Deferred systemic): SBRT alone with observation, reserving systemic therapy until radiographic progression not amenable to further SBRT (mrPD). SBRT is delivered per institutional standard; repeat SBRT is allowed until lesions become non-addressable. The primary endpoint, modified radiographic progression-free survival (mrPFS), is the time from randomization to death or radiographic progression not amenable to further MDT, defined by PCWG3 (bone) and modified RECIST 1.1 (soft tissue) criteria on conventional imaging. Soft-tissue progression requires ≥ 20% increase in measurable disease or a new lesion; bone progression requires ≥ 2 new confirmed lesions. Secondary endpoints include OS, biochemical PFS, time to local and distant progression, and grade 3–5 adverse events during systemic therapy. Exploratory endpoints evaluate EV and ctDNA kinetics as MRD markers, correlation of PSMA-positive EV burden with outcomes, and duration of response after short-course ADT/ARPI. Correlative analyses will longitudinally quantify PSMA-positive EVs and ctDNA at baseline, on treatment, and at progression to define MRD dynamics and resistance patterns. The trial uses Pocock–Simon dynamic allocation by EV strata and metastatic burden to ensure balance across arms. The trial is open and actively enrolling across all Mayo Clinic sites; as of October 2025, 35 of the planned 220 patients have been accrued. Clinical trial information: NCT06378866 .

514 Background: Poly(ADP-ribose) polymerase 1 (PARP1) senses single strand DNA damage and catalyzes repair mechanisms. PARP inhibitor (PARPi) suppresses PARP1 activity and promotes cell death in BRCA1 or BRCA2 mutated cancers that are homologous recombination repair deficient (HRD) via a phenomenon known as “synthetic lethality”. Utility of PARPi in HRD-negative (HRDn) cancers remain uncertain, although in a preclinical study overexpression—but not endogenous levels—of BRCA2 in mouse hybridoma cells led to HRD and increased sensitivity to DNA crosslinking agents, suggesting potential sensitization to PARPi. In renal cell carcinoma (RCC), HRD mutations are rare and the role of PARPi remains investigational. In this study, PARP1 and BRCA1/2 expression and overall survival (OS) in high risk of recurrence localized clear cell-type renal carcinoma (hrr-ccRCC) were explored. Methods: Batch-corrected bulk mRNA profile (RNA Seq V2 RSEM) and clinical data of HRDn stages II grade 4-only (n = 4) and III (n = 100) ccRCC from The Cancer Genome Atlas Pan-Cancer project were reviewed. Gene expression was classified “high” if mRNA level is higher than median, otherwise it was classified “low”. Survival analyses were Log-rank Kaplan-Meier. Group comparisons were two-tailed Mann-Whitney test. Results: In HRDn hrr-ccRCC (n = 104), BRCA1 and BRCA2 were upregulated by median fold change (mFC) of 1.6 and 3.7, respectively, whereas PARP1 was downregulated by mFC 0.8 compared to normal control (n = 72, all p < 0.0001). BRCA1 and BRCA2 levels were positively correlated (R 2 = 0.71). Median duration of follow-up for OS was 36.5 months (IQR 20.9-60.0). High BRCA2 (n = 54) was associated with superior OS compared to low BRCA2 (n = 50) with hazard ratio (HR) for death at 0.34 (95% CI 0.19-0.63, p = 0.0008). When high BRCA2 group was further stratified by PARP1 level, those with concomitant low PARP1 (n = 16) trended towards a superior OS compared to those with high PARP1 (n = 38) with HR 0.19 (95% CI 0.06-0.60, p = 0.067). Similarly, high BRCA1 (n = 53) was associated with superior OS compared to low BRCA1 (n = 51) with HR 0.53 (95% CI 0.29-0.96, p = 0.04). However, no differential OS was seen when high BRCA1 group was stratified by PARP1 level. No differential OS was seen when low BRCA1 or low BRCA2 groups were stratified by PARP1 level. Conclusions: In this retrospective analysis of HRDn hrr-ccRCC, high BRCA2 was associated with superior OS which was more pronounced with concomitant low PARP1 . High BRCA1 was also associated with superior OS, but PARP1 levels had no influence. The findings of this study may imply a potential therapeutic value of PARP1 suppression with PARPi by mimicking low PARP1 expression in treating HRDn hrr-ccRCC with BRCA2 overexpression. Further investigation is warranted.

496 Background: Approximately 10% of patients with renal cell carcinoma (RCC) have an associated venous tumor thrombus (VTT), the presence of which impacts surgical management and increases perioperative risk. Historical systemic therapy regimens had limited success in downsizing VTT; however, the impact of immune checkpoint inhibitors (ICIs) on VTT shrinkage is unknown. Our primary objective is to assess VTT shrinkage comparing responses to ICI versus non-ICI regimens. Methods: This multicenter retrospective cohort study included patients with RCC and VTT from 2006-2024 who received upfront systemic therapy. Patients were evaluated at tertiary referral centers across Mayo Clinic Rochester, Florida, and Arizona. Systemic therapies were categorized as ICI versus non-ICI regimens. VTT length was quantified by distance relative to the superior border of the renal vein ostium. The primary outcome was change in VTT length on serial imaging as measured by absolute length reduction (cm), RECIST version 1.1 criteria, and Mayo VTT level reclassification. Linear mixed-effect models (LMMs) identified associations with VTT shrinkage and clinicopathologic features. Results: A total of 108 patients with median age 65 years (IQR 57-71) were included, of whom 49 (45%) received ICI regimens. ICI regimens were associated with greater VTT shrinkage (1cm vs 0.1 cm, p=0.025), increased RECIST responses (51% vs 32%, p=0.046), and a higher rate downstaging per Mayo VTT level (33% vs 12%, p=0.008) compared to non-ICI regimens. On multivariable LMM analysis, ICI regimens remained more likely to result in VTT shrinkage compared to non-ICI regimens (-0.12 cm/month, 95% CI –0.24-0.00, p=0.046). Absence of abdominal lymphadenopathy was also associated with VTT shrinkage (-0.18cm/month, 95% CI -0.06- -0.30, p=0.004). Initial Mayo VTT level, IMDC risk, and number of metastatic sites were not associated with VTT shrinkage. Conclusions: Treatment with ICI-regimens resulted in VTT shrinkage and Mayo VTT level reduction. This is a particularly important area of exploration as radical nephrectomy and tumor thrombectomy carry up to a 40% risk of peri-operative major complications. These data support using ICI regimens for patients with RCC with VTT who are not candidates for upfront surgery and prioritizing ICI regimens in neoadjuvant clinical trials.

483 Background: Sarcomatoid dedifferentiation (sRCC) in metastatic clear-cell renal cell carcinoma (mccRCC) confers aggressive disease and poor prognosis. We maintain a living meta-analysis of first-line immune checkpoint inhibitor (ICI)–based combinations in mccRCC (Riaz et al., Eur Urol Oncol 2021), which demonstrated improved survival with ICI-based regimens over sunitinib. Here, we present an updated synthesis focused on the comparative efficacy of ICI combinations in the sarcomatoid subset. Methods: A systematic search of MEDLINE, EMBASE, and CENTRAL through October 2025 was performed as part of our living meta-analysis of first-line mccRCC therapy. Eligible phase III RCTs compared ICI combinations (IO/IO or IO/TKI) versus sunitinib, including CheckMate 214, CheckMate 9ER, KEYNOTE-426, CLEAR/KEYNOTE-581, JAVELIN Renal 101, and IMmotion151. Extracted outcomes included overall (OS) and progression-free survival (PFS), and objective (ORR), complete (CR), and partial (PR) response rates. Random-effects meta-analyses generated pooled hazard ratios (HRs) for time-to-event outcomes and risk ratios (RRs) for response rates with 95% confidence intervals. Subgroup interaction analyses compared sarcomatoid versus non-sarcomatoid subgroups, with p < 0.1 considered significant. Results: Six phase III RCTs (n = 5,121; 624 sarcomatoid) were included. Across all ICI-based combinations, ICI therapy improved outcomes versus sunitinib in both sarcomatoid and non-sarcomatoid disease. In the pooled analysis, the OS interaction favored sRCC meeting the prespecified significance threshold for subgroup analyses (HR 0.53 vs 0.68; p-interaction = 0.06 < 0.10), while no significant interaction was seen for PFS. Response outcomes showed the strongest differential benefit, particularly with IO/TKI regimens. IO/IO results were directionally consistent but limited by smaller non-sarcomatoid samples. Conclusions: ICI-based combinations significantly improve survival and response outcomes versus sunitinib in mccRCC. Using a prespecified α = 0.10 for interaction testing, the pooled analysis showed a significant OS interaction and higher response rates in sRCC, indicating enhanced ICI sensitivity. These updated meta-analysis data support ICI regimens as the preferred first-line therapy for mRCC with sarcomatoid de-differentiation. Endpoint Regimen Subgroup (S = sarcomatoid; NS = non-sarcomatoid) Effect (95% CI) p-interaction PFS IO/IO S 0.51 (0.40–0.65) – IO/TKI S vs NS 0.48 (0.36–0.64) vs 0.46 (0.39–0.52) 0.81 OS IO/IO S 0.54 (0.07–4.42) – IO/TKI S vs NS 0.51 (0.17–1.48) vs 0.68 (0.30–1.58) 0.24 ORR IO/IO S 2.93 (0.49–17.37) – IO/TKI S vs NS 2.43 (1.84–3.21) vs 1.95 (1.67–2.28) 0.03 CR IO/IO S 3.81 (0.82–17.71) – IO/TKI S vs NS 5.93 (4.73–7.42) vs 2.85 (0.10–83.73) 0.007 PR IO/IO S 3.48 (1.70–7.11) – IO/TKI S vs NS 2.10 (1.78–2.47) vs 1.75 (1.18–2.61) <0.001

476 Background: Lack of standardized reporting and collection of patient-reported outcomes (PROs) limits cross-trial comparisons of first-line IO-based regimens for mRCC. Prospectively collected real world data may fill this important knowledge gap. Pts with stable/improved QoL at 3 mo versus baseline have longer median OS than pts with worse/unobserved HRQoL versus baseline (Cella, 2024). Methods: ODYSSEY is a multi-site, prospective observational study of 468 US pts with mRCC. Pts must have mRCC (any histology), no prior systemic therapy (ST), and follow up at a PCORnet study site. Exclusion criteria include treatment for cancer except mRCC. Descriptive statistics are used to show PRO score changes from baseline. We evaluate longitudinal change from baseline in PRO scores using least squares mean (LSM). Minimally important differences (MID) are 3 points for FKSI-19 total score, 1 point for the FKSI-Disease Related Symptoms (DRS) subscale and 7 points for FACT-G. Higher score indicates better QOL. The primary objective is to determine patterns of change in QOL and symptom burden of pts with mRCC. Results: As of 10/1/25, 360 pts were managed with ST, including 266 pts on IO-based combinations: 35 cabozantinib + nivolumab (C+N), 49 lenvatinib + pembrolizumab (L+P), 40 axitinib + pembrolizumab (A+P), and 142 ipilimumab + nivolumab (I+N). Overall median follow-up is 12.1 mos (IQR 6, 24). Age, sex and race were similar across regimens. Prior nephrectomy (50%) was lower than in trials. C+N and L+P pts had less clear cell (56 and 65%) versus A+P and I+N pts (94 and 82%). A+P pts had more favorable IMDC risk (19%) and less poor risk (14%). Baseline QOL was variable across regimens, with L+P generally the lowest. Absolute changes in PROs from enrollment to mo 3 (early change) by regimen are shown in the Table. LSM change from baseline in FKSI-19 and FKSI-DRS favored IO-IO versus IO-TKI at 3 mos but not at 6 mos (not shown). Conclusions: While early change in PROs did not meet the MID threshold between the IO-TKI and I+N cohorts, different patterns of early change are apparent among specific IO-TKI regimens. IO-TKI regimens exhibited higher variation in early PRO change vs I+N. As the data matures, we will associate baseline PROs and early PRO changes with early death and other outcomes. Clinical trial information: NCT04919122 . 3 month change. Instrument C+N (N=35) L+P (N=49) A+P (N=40) All IO-TKI(N=124) I+N(N=142) FKSI-19, N (%) 26 (74) 33 (67) 33 (83) 92 (74) 104 (73) Mean (SD) -0.3 (11) 2.8 (13) -3.2 (12) -0.2 (12) 0.7 (10) Median (IQR) 1.4 (-7, 6) 5.0 (-7, 11) -1.0 (-14, 5) 1.4 (-10, 8) -0.3 (-5, 6) FKSI-DRS, N (%) 26 (74) 33 (67) 33 (83) 92 (74) 104 (73) Mean (SD) -0.8 (5) 1.5 (7) -1.8 (6) -0.3 (6) 0.8 (5) Median (IQR) -0.5 (-5, 3) 2.0 (-5, 5) -1.0 (-5, 3) 0.0 (-5, 4) 0.0 (-2, 4) FACT-G, N (%) 27 (77) 32 (65) 29 (73) 88 (71) 102 (72) Mean (SD) 2.1 (14) 5.2 (16) -3.5 (15) 1.4 (15) 0.3 (13) Median (IQR) 4.0 (-4, 10) 1.2 (-6, 13) -6.4 (-11, 4) 1.6 (-8, 10) 1.6 (-7, 8)

464 Background: Based on LITESPARK-005 trail, Belzutifan was FDA-approved to treat advanced RCC following ICI and a VEGF-TKI. We conducted a retrospective cohort study to report the real-world outcomes of Belzutifan in pre-treated RCC patients. Methods: A retrospective chart review of all patients who received Belzutifan at the Mayo Clinic Comprehensive Cancer Center between Dec 2023 and Sep 2025 was conducted. Patients treated for sporadic RCC were eligible; those with von Hippel–Lindau disease, non-RCC pathologies (e.g., Pheochromocytoma, ovarian cancer) were excluded. Radiologic response was assessed by trained curators using RECIST-defined criteria, approximated through systematic review of radiology reports with clinician adjudication when needed. Progression-free survival (PFS), defined as the time from treatment initiation to radiographic progression or death, was estimated using the Kaplan–Meier method. Non-progressors were censored at the last radiology assessment. Patients who discontinued therapy for non-progression reasons were censored at the last radiology assessment prior to discontinuation. Any-cause hypoxia and anemia were reported using CTCAEv5 definitions. Results: A total of 158 patients were identified; 83 (52.5%) who received Belzutifan for sporadic RCC were included. The remaining were excluded for VHL disease (68, 43%) or other pathologies (7, 4.4%). Median follow up was 12 months, 67% were male, median age was 70 (range 39, 94) with 57 patients (69%) were ≥ 65. 28 patients (34%) had a poor IMDC score at baseline. The cohort received a median of 3 previous lines of therapy (range 1,8). Median treatment duration was 3 months (IQR: 1-9.5). Median PFS was 5.7 months (95% CI, 3.8–8.7). At 12 and 18 months, 23.1% and 13.9% of patients, respectively, remained alive and progression-free. Corresponding OS rates at these time points were 60.2% and 51.5%. A confirmed ORR occurred in 12 patients (14.4%). Hypoxia occurred in 44 (53%) patients, median onset 31 days (range 1–270) and 29 (34.9%) required hospitalizations. Median hemoglobin (Hb) levels at baseline were 12.65 g/dl (range, 7.2-15.5), and 68 (82%) patients developed Hb decline on Belzutifan, 27 (32.5%) required transfusions. Conclusions: In an older, high-risk cohort with higher number of prior lines of therapy, Belzutifan yielded PFS/OS and ORR landmarks comparable to the trial supporting its effectiveness in the real world. Outcomes compared with LITESPARK-005 trial. Variable Real world cohort (Mayo Clinic) LITESPARK-005, Belzutifan arm Median PFS (months, 95% CI) 5.7 (3.8-8.7) 5.6 (3.9-7) 12-month PFS rate (%, 95% CI) 23.1% (14.4-33.4) 33.4% (28.4-33.5) 18-month PFS rate (%, 95% CI) 13.9% (7.7-23.9) 24% (19-29.4) 12-month OS rate (%, 95% CI) 60.2% (48.9-70.8) 67.9% (62.9-72.4) 18-month OS rate (%, 95% CI) 51.5% (40.6-62.9) 55.2% (50-60.1) ORR (%, 95% CI) 14.4% (7.7-23.9) 21.9% (17.8-26.5)

214 Background: 177 Lu-PSMA-617 (LuPSMA) has revolutionized care for patients (pts) with metastatic castrate-resistant prostate cancer (mCRPC), but only half achieves PSA decline ≥50%. Biomarkers are urgently needed to improve pt selection. EVs and ctDNA released by cancer cells into the blood are emerging biomarkers to estimate overall tumor burden and capture tumor heterogeneity in mCRPC. Here, we analyzed pre-treatment plasma levels of tumor EVs and ctDNA in a pilot cohort of 35 pts with mCRPC treated with LuPSMA. Methods: Blood samples were collected pre-cycle 1 of LuPSMA at Tulane Cancer Center between 12/2018-1/2025. Plasma-derived small and large EVs were incubated with fluorescently conjugated antibodies and enumerated using nanoscale flow cytometry. ctDNA fraction was estimated from plasma cfDNA methylation WGS (∼10×) with ichorCNA. We also analyzed EVs from blood samples of male healthy donors (HD) and pts with localized prostate cancer (LPC) collected 1 day to 8 months after radical prostatectomy (post-RP) from 6/2020-8/2024 at Mayo Clinic as controls. Results: Median age at collection for 10 HD was 55 yrs and for 36 pts with LPC post-RP was 65 yrs. Median PSMA+ EV level was 2.0 x 10 6 /mL for post-RP and 1.4 x 10 6 /mL for HD. For 35 pts with mCRPC, 25 pts had complete data for analysis. Median PSMA+ EV level was 1.4 x 10 7 /mL, significantly higher than post-RP (p<0.001) and HD (p<0.001). At LuPSMA start, median age was 69 yrs (range 54-83), PSA was 82 ng/mL (range 0.8-503), median time from CRPC diagnosis to start was 50 months (range 6.9-285), median time from plasma collection to treatment initiation was 0.5 months (range 0-7.3). Median number of prior lines of life-extending therapy was 4 (range 1-11), including 100% androgen receptor pathway inhibitor and 75% docetaxel. Pts received median 4 cycles of LuPSMA. Median ctDNA fraction was 14.0% (range 0-51.1). Median time to reach nadir PSA for pts with any decline was 2.6 months. 15 pts (60%) achieved PSA40 (defined ≥40% decline in PSA from start to nadir) (range -99% to -42%) compared to 10 pts (40%) who did not (range -16% to rise), which predicted better median overall survival (OS) after LuPSMA start (40.7 v 6.0 months; HR 0.23, 95% CI, 0.07-0.71; p=0.0001). Pts were classified as LuPSMA responders using PSA40. Responders had a lower ratio of large to small PSMA+ EVs (0.30 v 0.53, p=0.0042) with an area under the receiver operating characteristic curve (AUC) of 0.83 (95% CI, 0.68-0.99), and a lower median ctDNA fraction (6.1% v 26.2%, p=0.0044) with an AUC of 0.83 (95% CI, 0.68-1.00). Incorporating both PSMA+ EV and ctDNA fraction together predicted PSA40 response with an AUC of 0.93 (95% CI, 0.84-1.00, p=0.0003). Conclusions: Using pre-LuPSMA plasma samples from a heavily pre-treated historical cohort, we integrated non-invasive liquid biopsy methods to successfully predict response to LuPSMA using PSA decline. Prospective validation is underway.

BACKGROUND: Left ventricular (LV) dysfunction is a potential cardioembolic source of ischemic stroke, but its role in recurrent stroke risk and treatment response remains unclear. We explore whether LV injury associates with the risk of recurrent stroke and modifies the association between anticoagulation and stroke recurrence using real-world data. METHODS: We performed a multicenter, retrospective study of Cardiac Abnormalities in Stroke Prevention and Recurrence cohort across 27 US sites. Patients with LV ejection fraction ≥20% were included. LV injury, defined as LV ejection fraction 20% to 40% and wall motion abnormality, was the primary exposure and treatment effect modifier. The treatment of interest was anticoagulant versus antiplatelet therapy. The composite outcome included recurrent stroke, major bleeding, or death. Outcomes were evaluated using unadjusted and inverse probability weighting adjusted Cox proportional hazards models, with treatment effect modification tested by LV injury status. RESULTS: Among 2685 patients enrolled, 2328 with complete data were analyzed (median age, 65 years; 49.8% female; median follow-up, 1.6 years). LV injury was present in 310 patients (13.3%). Overall, 535 events occurred: 258 recurrent ischemic strokes, 28 hemorrhagic strokes, 67 major hemorrhages, and 256 deaths. LV injury was associated with a higher unadjusted risk of the primary outcome (hazard ratio [HR], 1.51 [95% CI, 1.21–1.87]), though nonsignificant after inverse probability weighting adjustment (adjusted HR, 1.29 [95% CI, 0.97–1.70]). In the LV injury subgroup, anticoagulation versus antiplatelet therapy was associated with a lower risk of the primary outcome (adjusted HR, 0.24 [95% CI, 0.10–0.59]), relative to the non-LV injury subgroup (adjusted HR, 1.28 [95% CI, 0.83–1.95]; p[LV-interaction], 0.001). Similar interactions were seen for EF 20% to 40% (versus >40%; adjusted HR, 0.19 [95% CI, 0.04–0.86]; p[LV-interaction], 0.001) and wall motion abnormality (versus no wall motion abnormality; adjusted HR, 0.33 [95% CI, 0.15–0.73]). CONCLUSIONS: After cryptogenic stroke, anticoagulation in those with LV injury was associated with lower rates of recurrent stroke, major bleeding, and death. These findings warrant confirmation in a dedicated randomized controlled trial. REGISTRATION: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT06398366.