Citations

TPS2699 Background: Despite the success in hematologic cancers, chimeric antigen receptor (CAR) T-cell therapies are challenging to implement in solid tumors owing to a lack of tumor-specific targets that discriminate cancer from normal cells. MSLN expression normally is limited to the mesothelium of major body cavities but can be upregulated in diverse solid tumor types (TCGA 2022), making it a potential target for cancer therapy. MSLN-targeted cell approaches, including CAR T-cell and T-cell receptor fusion therapies, have shown promising clinical activity; however, on-target, off-tumor toxicity including fatal events have occurred (1-3). A2B694 is an autologous logic-gated, MSLN-targeted Tmod CAR T-cell therapy that addresses the challenges of on-target, off-tumor toxicity by combining 2 CARs: an activating and blocking receptor. The activator recognizes MSLN present on the surface of both tumor and normal cells; the blocker binds HLA-A*02 and prevents CAR T-cell activity. Thus, in patients with both germline HLA-A*02 and tumor-associated HLA-A*02 LOH, the blocker prevents on-target, off-tumor toxicity on normal cells owing to retained HLA-A*02 expression (4). Through this unique discriminatory mechanism, A2B694 may provide a therapeutic window to treat patients with MSLN-expressing solid tumors exhibiting HLA-A*02 LOH. Methods: EVEREST-2 (NCT06051695) is a first-in-human, phase 1/2, open-label, nonrandomized study to evaluate the safety and efficacy of A2B694 in adults with recurrent unresectable, locally advanced, or metastatic cancers with MSLN expression, including non-small cell lung cancer, colorectal cancer, pancreatic cancer, ovarian cancer, mesothelioma, or other solid tumors with MSLN expression. Eligible patients should have received ≥1 line of prior therapy such as checkpoint inhibitor, molecular targeted, or chemotherapy. Enrollment to EVEREST-2 occurs through the prescreening study BASECAMP-1 (NCT04981119), which identifies patients with tumor-associated HLA-A*02 LOH via next-generation sequencing (Tempus AI, Inc.). Eligible patients enroll in the BASECAMP-1 study and undergo leukapheresis. A2B694 is manufactured from cryopreserved T cells when clinically appropriate for patients. The primary objective of phase 1 is to evaluate the safety and tolerability of A2B694 and identify the recommended phase 2 dose (RP2D). The dose-expansion phase will confirm RP2D and collect biomarker data to further characterize A2B694. Phase 2 will assess overall response rate per RECIST v1.1. 1. Beatty, et al. Gastroenterology. 2018. 2. Haas, et al. Mol Ther. 2023. 3. Hong, et al. ESMO 2021. Abstract 9590. 4. Hamburger, et al. Mol Immunol. 2020. Clinical trial information: NCT06051695 .

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.

4136 Background: NAPOLI 3 (NCT04083235, N = 770), a global, randomized, open-label phase 3 study, demonstrated that NALIRIFOX significantly improved overall survival (OS, primary endpoint) and progression-free survival compared with nab-paclitaxel and gemcitabine in patients with untreated mPDAC. Here, we report an updated analysis of OS. Methods: Eligible patients with histopathologically/cytologically confirmed untreated mPDAC were randomized (1:1) to receive liposomal irinotecan 50 mg/m2 + oxaliplatin 60 mg/m2 + leucovorin 400 mg/m2 + 5-fluorouracil 2400 mg/m2 (NALIRIFOX, n = 383) on days 1 and 15 of a 28-day cycle or nab-paclitaxel 125 mg/m2 and gemcitabine 1000 mg/m2 (Gem+NabP, n = 387) on days 1, 8 and 15 of a 28-day cycle. Randomization was stratified by ECOG performance status, geographic region and presence/absence of liver metastases. An updated OS analysis (data cutoff: 3 October 2023) was conducted. Kaplan–Meier methods were used to estimate median (95% confidence interval [CI]) OS and hazard ratios (HRs [95% CI]) were estimated using stratified Cox proportional hazard models. The difference between groups was tested using a stratified log-rank test. Results: The median follow-up for OS was 28.7 months in the NALIRIFOX arm and 29.7 months in the Gem+NabP arm. At data cutoff, 11 patients were still receiving study treatment, all of whom were in the NALIRIFOX arm. With a total of 673 OS events (NALIRIFOX, n = 328; Gem+NabP, n = 345), median OS was 11.1 months (95% CI 10.0–12.1) in the NALIRIFOX arm compared with 9.2 months (8.3–10.6) in the Gem+NabP arm (HR 0.84 [95% CI 0.72–0.98]; nominal p = 0.026). At 12 months and 18 months, survival rates were 45.6% (95% CI 40.5–50.5) and 26.6% (22.2–31.1), respectively, in the NALIRIFOX arm and 39.6% (34.7–44.5) and 20.0% (16.1–24.1), respectively, in the Gem+NabP arm. Conclusions: In this 29-month follow-up of NAPOLI 3, NALIRIFOX continued to demonstrate improved OS compared with Gem+NabP, with 11 patients still receiving the NALIRIFOX regimen. These data confirm NALIRIFOX as a new possible standard of care and reference regimen for the first-line treatment of patients with mPDAC. Clinical trial information: NCT04083235 .

Abstract Alpha-tubulin 4A encoding gene (TUBA4A) has been associated with familial amyotrophic lateral sclerosis and frontotemporal dementia, based on identification of likely pathogenic variants in patients from distinct amyotrophic lateral sclerosis and frontotemporal dementia cohorts. By screening a multicentric French cohort of 448 unrelated probands presenting with cerebellar ataxia, we identified ultra-rare TUBA4A missense variants, all being absent from public databases and predicted pathogenic by multiple in silico tools. In addition, gene burden analyses in the 100 000 Genomes project (100KGP) showed enrichment of TUBA4A rare variants in the inherited ataxia group compared to controls [odds ratio: 57.0847 (10.2−576.7); P = 4.02 ×10−7]. Taken together, we report 12 patients presenting with spasticity and/or cerebellar ataxia and harbouring a predicted pathogenic TUBA4A missense mutation, including five confirmed de novo cases and a mutation previously reported in a large family presenting with spastic ataxia. Cultured fibroblasts from three patients harbouring distinct TUBA4A missense showed significant alterations in microtubule organization and dynamics, providing insight of TUBA4A variants pathogenicity. Our data confirm the identification of a hereditary spastic ataxia disease gene with variable age of onset, expanding the clinical spectrum of TUBA4A associated phenotypes.

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]

The New Zealand rabbit elastase-induced arterial aneurysm of the right common carotid artery remains a widely used model for assessing the effectiveness and safety of new neuroendovascular devices.1 This model offers a simple and reliable platform for pre-clinical in vivo investigations, crucial for comprehending the biological processes underlying aneurysm healing after endovascular treatment.2 Notably, the induced aneurysm exhibits morphological, hemodynamic, and histological characteristics similar to human intracranial aneurysms. The creation of the aneurysm is performed using open and endovascular techniques. Each step of the procedure requires a meticulous and controlled gesture to ensure reproducibility of the aneurysm and minimize animal misuse. In video 1 we present a step-by-step procedural guide for aneurysm creation and follow-up. We hope this resource will help in promoting this model and provide useful guidance for researchers in the field. Video 1 Surgical procedure of creating elastase-induced aneurysms in rabbits.

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 .