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3553 Background: Vilastobart (XTX101) is tumor-activated, high affinity, Fc-enhanced aCTLA-4 designed to focus activity toward the tumor and minimize systemic adverse events. Fc-enhancement augments FcγR co-engagement on antigen presenting cells and has been linked with efficacy of aCTLA-4 combinations in patients (pts) with microsatellite stable (MSS) colorectal cancer (CRC) and other tumors [Fakih ASCO GI 2025]. Vilastobart was generally well-tolerated and demonstrated evidence of anti-tumor activity in pts with immunologically “cold” advanced solid tumors, both as a monotherapy and in combination with atezolizumab [Davar SITC 2024]. Methods: Phase 2 of the NCT04896697 study evaluated the initial recommended Phase 2 dose of vilastobart 100 mg Q6W in combination with atezolizumab 1200 mg Q3W in pts with MSS CRC who had at least 1 prior chemotherapy regimen in the metastatic setting, excluding pts with prior immune checkpoint inhibitors. Pts with (LM) and without liver metastasis (NLM) were eligible. Tumor biopsies were obtained before and during treatment for translational analyses. Results: As of January 13, 2025, 40 pts were dosed in Phase 2. Median age was 55 (25-82) and 70% of pts had 3 or more prior lines of therapy. Of the 24 enrolled NLM pts, 11 were response-evaluable with an available on-treatment scan as of the data cut. In these 11 pts, two confirmed and one unconfirmed partial response (PR) were reported, all accompanied by significant decreases in ctDNA and serum tumor marker CEA and with each pt ongoing on therapy, for a preliminary ORR of 27%. One additional pt (with peritoneal metastasis) had a 24% reduction in target lesions (first scan) and was ongoing on therapy. Of the 16 enrolled LM pts, 7 were response evaluable, with one stable disease and another pt reporting a mixed response with significant serum tumor marker reductions, both ongoing on therapy. Of note, one LM pt in Phase 1C dose escalation treated with vilastobart (150 mg Q6W) combination had a confirmed PR with LM resolution. Six pts (15%) reported G3+ treatment-related adverse events (TRAEs), with two G4 laboratory TRAEs and no G5 TRAEs. Only three pts discontinued therapy for TRAEs. TRAEs occurring in ≥10% (all grade) or ≥5% (G3) of pts are summarized in the Table. Conclusions: The combination of vilastobart, a novel tumor-activated, Fc-enhanced a-CTLA-4, and atezolizumab demonstrated initial evidence of anti-tumor activity in late line, metastatic MSS CRC where immune checkpoint blockade has historically been relatively ineffective. Vilastobart was observed to have a differentiated safety profile distinct from systemically active a-CTLA-4, consistent with tumor-selective activation. Clinical trial information: NCT04896697 . AE term All Graden (%) Grade 3n (%) Fatigue 12 (30%) 0 Diarrhea 8 (20%) 0 Infusion related reactions 5 (13%) 0 Pyrexia 4 (10%) 0 ALT increased 4 (10%) 0 AST increased 4 (10%) 1 (3%) Colitis 2 (5%) 2 (5%)

e19515 Background: The prevalence of diabetes mellitus (DM) is significantly higher in patients with multiple myeloma (MM) compared to the general population. DM has been associated with worse outcomes in MM, including reduced overall survival and increased mortality. The impact of diabetes in patients with MM is further compounded by cardiotoxicity from proteasome inhibitors and the increased thromboembolic risk linked to immunomodulatory agents. Given the potential benefits of sodium-glucose cotransporter-2 (SGLT2) inhibitors, we hypothesized that their use in MM patients with DM could improve clinical outcomes and mitigate adverse events in this population. Methods: We utilized the TriNetX network to identify patients (≥18 years old) with MM and DM between January 1, 2013, and January 1, 2019. We categorized the patients into SGLT2 inhibitors users and SGLT2 inhibitors users. Inclusion in the SGLT2 inhibitors group required exposure to SGLT2 inhibitors for at least 1 year. 1:1 Propensity score matching was performed to match these two groups based on comorbidities, medications, baseline hemoglobin A1c, low-density lipoprotein, and left ventricular ejection fraction to produce two comparable cohorts. The study outcomes include all-cause mortality, all-cause hospitalization, acute venous thromboembolism (VTE), acute heart failure (HF), acute myocardial infarction (MI), cardiac arrhythmia, and cardiac arrest over the 5-year follow-up duration. Results: A total of 43,078 patients were identified, including 3,640 SGLT2 inhibitors users and 39,438 non-SGLT-2 inhibitors users. After 1:1 propensity-score matching, there were 3,379 SGLT-2 inhibitor users (68.9 ± 10.3 years of age, 38.0% female, 23.9% African American [AA]) and 3,379 non-SGLT-2 inhibitor users (68.9 ± 11.0 years of age, 35.9% female, 22.2% AA). SGLT-2 inhibitors users were associated with lower rates of all-cause mortality (odds ratio [OR]: 0.34, 95% confidence interval [CI]: 0.30-0.39) and all-cause hospitalization (OR: 0.52, 95% CI: 0.47-0.58). Lower odds of acute VTE (OR: 0.59, 95% CI: 0.49-0.70), acute HF (OR: 0.89, 95% CI: 0.81-0.98), acute MI (OR: 0.81, 95% CI: 0.69-0.95), cardiac arrhythmia (OR: 0.82, 95% CI: 0.70-0.97), and cardiac arrest (OR: 0.57, 95% CI: 0.44-0.74) were reported among SGLT-2 inhibitors users compared to non-SGLT2 inhibitor users. Conclusions: Our study revealed that only 8.4% of patients with DM and MM were prescribed an SGLT-2 inhibitor. Our study also demonstrated that SGLT2 inhibitor use was associated with lower odds of all-cause mortality and hospitalization, reduced risk of VTE, and favorable cardiovascular outcomes in this patient population.

Objective Specific sedative hypnotic agents, administered to facilitate endotracheal intubation (ETI) in critically ill adults, may lead to adverse outcomes such as peri-intubation cardiovascular collapse. However, little is known from systematic investigations of the impact these individual agents have on cardiovascular function or other clinical outcomes. Data sources MEDLINE, Embase, CENTRAL, ClinicalTrials.gov, Scopus and Web of science databases. Study selection We conducted a systematic search for randomized and non-randomized studies that evaluated adult (≥18 years) critically ill patients who were sedated to facilitate ETI with ketamine, propofol, ketamine/propofol, etomidate, or a benzodiazepine and who had data on peri-intubation hemodynamics and at least one other outcome involving acute kidney injury, delirium, opioid use, intubation difficulty, sequential organ failure assessment, length of stay, or mortality. Eighty-five studies were identified for eligibility assessment with 23 included in the analysis. Data extraction Two reviewers independently screened articles, extracted data from selected articles, and assessed risk of bias using ROBINS-I for observational studies and revised Cochrane Risk of Bias tool for randomized controlled trials. Data synthesis Acute cardiovascular dysfunction (peri-intubation hemodynamic instability and/or cardiac arrest) was similar between etomidate and ketamine with more events seen when propofol versus non-propofol sedation was administered. However, exploratory meta-analysis demonstrated no difference between etomidate and ketamine (OR 1.05 [95%CI 0.60-1.84]) or between etomidate and propofol (OR 0.91 [95%CI 0.33-2.46]). Compared to ketamine, etomidate demonstrated lower survival to hospital discharge in the included studies in exploratory meta-analysis OR 0.76 (95%CI 0.62-0.92). Limited data existed for other outcomes with no discernible differences between sedative agents. Conclusions Acute cardiovascular dysfunction was more common when propofol, as compared to non-propofol sedation, was administered, although not statistically significant in exploratory meta-analysis. In addition, etomidate conferred lower survival to hospital discharge versus non-etomidate sedation, which was confirmed in exploratory meta-analysis of etomidate versus ketamine.

Abstract Background Coronary computed tomography angiography (cCTA) is a widely used noninvasive diagnostic exam to assess patients for coronary artery disease (CAD). However, the spatial resolution of most CT scanners is limited due to the use of energy‐integrating detectors (EIDs). Purpose To develop a convolutional neural network ( I mproved LUMEN visualization through A rtificial super‐resolu T ion imag E s (ILUMENATE)) informed by photon‐counting‐detector (PCD)‐CT to improve EID‐CT image resolution and determine its impact on cCTA. Materials and methods With IRB approval, 30 patients undergoing clinically indicated cCTA were scanned with EID‐CT (SOMATOM Force, Siemens Healthineers, Forchheim, Germany) and subsequently with ultra‐high‐resolution (UHR) PCD‐CT (NAEOTOM Alpha, Siemens Healthineers) on the same day. ILUMENATE was trained on eight patient PCD‐CT datasets (67,890 patch pairs with 90% for training (61,101), 10% reserved for validation (6,789)) and applied to 22 unseen EID‐CT cases. Spatial resolution was evaluated using line profiles and percent diameter stenosis quantified with a severity score assigned. Two experienced radiologists, blinded to image type, selected preferred series and scored images for overall quality, sharpness, and noise comparing original EID‐CT and ILUMENATE output. Results Visual assessment and line profiles showed substantial resolution improvement with ILUMENATE. Percent diameter stenosis was significantly reduced (mean ± standard deviation: 4.42% ± 4.82%) using ILUMENATE ( p < 0.001) with nine lesions shifting down in severity score. Readers preferred ILUMENATE images in 22/22 cases and scored ILUMENATE superiorly for overall quality, sharpness, and noise ( p < 0.05). Conclusions ILUMENATE enhanced image resolution, resulting in improved overall image quality, reduced calcium blooming artifacts, and improved lumen visibility in cCTA exams performed using EID‐CT. This could potentially allow for improved accessibility to UHR image quality, allowing for more accurate assessment of CAD.

PURPOSE Randomized clinical trials (RCTs) have shown progression-free survival (PFS) benefits of metastasis-directed therapy (MDT) without androgen deprivation therapy for oligometastatic castration-sensitive prostate cancer (omCSPC). Most patients with bone metastatic (BM) omCSPC recur with additional bone disease after MDT. We hypothesized the BM-targeting alpha-emitter radium-223 dichloride (Ra223) could target subclinical bone disease and delay progression. METHODS This is an investigator-initiated, multicenter, open-label phase II RCT. Eligible men with recurrent omCSPC with ≥one bone metastasis (≤three on conventional imaging and/or ≤five on molecular imaging) were randomly assigned (1:1) to stereotactic ablative radiation (SABR) MDT alone or SABR MDT with Ra223 (six cycles). Primary end point was composite PFS. RESULTS From August 9, 2019, to March 2, 2023, 64 patients were randomly assigned, 33 to SABR MDT and 31 to SABR MDT/Ra223 balancing for key covariates. Most SABR MDT/Ra223 patients (87%) received six cycles of Ra223. The median PFS was 11.8 months with SABR MDT and 10.5 months with SABR MDT/Ra223 (adjusted hazard ratio [aHR], 1.42 [95% CI, 0.79 to 2.56]; P = .24). Seven patients (11%) experienced grade 3 treatment-related adverse events (no grade 4 or 5), 2 of 33 (6%) with SABR and 5 of 30 (17%) with SABR MDT/Ra223. Patients with high-risk (HiRi) pathogenic mutations in ATM , BRCA1/2 , RB1 , or TP53 had worse PFS (HR, 5.95 [95% CI, 1.83 to 19.3]; P = .003). Greater T-cell receptor (TCR) unique productive rearrangements were prognostic for improved PFS independent of the treatment arm (aHR, 0.45 [95% CI, 0.21 to 0.96]; P = .04). CONCLUSION Adding Ra223 to SABR MDT in BM omCSPC does not delay progression of disease. We provide evidence for an HiRi mutational signature and TCR repertoire as prognostic biomarkers in omCSPC treated with SABR MDT, highlighting the importance of collecting biological correlates in RCTs for omCSPC.

Human immune system (HIS) mice constructed in various ways are widely used for investigations of human immune responses to pathogens, transplants, and immunotherapies. In HIS mice that generate T cells de novo from hematopoietic progenitors, T cell-dependent multisystem autoimmune disease occurs, most rapidly when the human T cells develop in the native NOD.Cg- Prkdc scid Il2rg tm1Wjl (NSG) mouse thymus, where negative selection is abnormal. Disease develops very late when human T cells develop in human fetal thymus grafts, where robust negative selection is observed. We demonstrate here that PD-1 + CD4 + peripheral (Tph) helper-like and follicular (Tfh) helper-like T cells developing in HIS mice can induce autoimmune disease. Tfh-like cells were more prominent in HIS mice with a mouse thymus, in which the highest levels of IgG were detected in plasma, compared to those with a human thymus. While circulating IgG and IgM antibodies were autoreactive to multiple mouse antigens, in vivo depletion of B cells and antibodies did not delay the development of autoimmune disease. Conversely, adoptive transfer of enriched Tfh- or Tph-like cells induced disease and autoimmunity-associated B cell phenotypes in recipient mice containing autologous human APCs without T cells. Tfh/Tph cells from mice with a human thymus expanded and induced disease more rapidly than those originating in a murine thymus, implicating HLA-restricted T cell-APC interactions in this process. Since Tfh, Tph, autoantibodies, and lymphopenia-induced proliferation (LIP) have all been implicated in various forms of human autoimmune disease, the observations here provide a platform for the further dissection of human autoimmune disease mechanisms and therapies.

Abstract Background: Leukocyte immunoglobulin-like receptor B2 (LILRB2) suppresses immune cell activation, particularly within myeloid cells in the tumor microenvironment (TME), while the PD-1/PD-L1 axis serves as a key immune checkpoint that inhibits T-cell function. SPX-303 is a novel bispecific antibody designed to simultaneously block LILRB2 and PD-L1, thereby revitalizing antitumor immune responses. Here, we present initial findings from the ongoing first-in-human Phase 1 trial of SPX-303 in patients with advanced solid tumors, including safety, pharmacokinetics (PK), and receptor occupancy (RO). Methods: This is an open-label, multicenter Phase 1 study for patients with advanced solid malignancies with 3+3 dose-escalation design, followed by an expansion cohort at the recommended Phase 2 dose (RP2D). SPX-303 is administered intravenously every three weeks and safety is assessed through CTCAE v5.0 criteria. Primary Objectives of this study are to determine the safety, tolerability, and RP2D of SPX-303. Secondary endpoints include antitumor activity as well as characterization of the PK and PD of SPX-303. This study is currently open and enrolling in escalation cohorts. Citation Format: Justin Moser, Hao Xie, Yujie Zhao, Yousef Zakharia, Dongdong Li, Brandon William, Dinh-Duc Nguyen, Jack Hovey, Tiffany Li, Robert Cai, Jichun Ma, Jingdong Qin, Martin Siekierzycki, Anthony Haight, Hua Jin, Weiwei Mao, Kevin Bin Li, Gui-Dong Zhu. A first-in-human phase 1 study on the safety, PK, receptor occupancy, and pharmacodynamic markers of SPX-303, a first-in-class LILRB2×PD-L1 bispecific antibody [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_2):Abstract nr CT116.