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Abstract Background: Prognostication for patients with non-transformed relapsed/refractory (R/R) follicular lymphoma (FL) is not well defined. Progression of disease within 24 months (POD24) and number of lines of prior therapy are commonly used to benchmark outcomes and for trial eligibility in this space. However, a comprehensive model for risk prediction in R/R FL is lacking. Here we utilize patients from the LEO Consortium for Real World Evidence (CReWE) and Iowa/Mayo Clinic Lymphoma SPORE MER to develop a clinical prediction model for R/R FL. Methods: Patients with grade 1-3A FL were prospectively enrolled at diagnosis in the MER and/or initiated second line or later therapy (2L+) for non-transformed FL at one of the 8 LEO Centers from a previous LEO CReWE study (Casulo et al, Lancet Haem 2022). All available lines of therapy were abstracted; lines of therapy after histologic transformation were not used in the analyses. A management plan of observation was considered as a type of therapy in the 1L setting but not in the 2L+ setting. Clinical variables and outcomes were abstracted at each line of therapy. Variables considered for modeling included demographics, clinical labs, treatment history, and pertinent clinical variables (including FLIPI and FLIPI24 components). Multiple imputation was used to address missing data in modeling; beta-2 microglobulin (B2M) was unable to be imputed due to the amount of missing data. Index therapy was defined as the date of initiation of a line of therapy (2L, 3L or 4L) for non-transformed FL. The primary endpoint for model development was the time from index therapy until the histologic transformation or lymphoma-related death (HT/LD). Cox proportional hazards models were used for model development. Modeling was first performed separately for each line of therapy and then evaluated across lines. Bootstrapping on imputed datasets was used to assess optimism in model performance. Results: N=1001 patients initiated 2L+ therapy and were utilized for modeling. Of these patients, N=654 initiated 3L and N=344 initiated 4L therapy. Median age at index therapy was (60, 61, and 62) for lines 2-4, respectively. Median follow-up by line of therapy was 8.2, 6.1, and 6,1 years and number of HT/LD events for modeling was 272, 154, and 88, respectively. Observed outcomes decreased modestly as the line therapy increased: median event-free (1.6, 1.5, and 1.2 years) and overall survival (17.6 years, 14.5 years, and 12.3 years), for lines 2-4, respectively. 5-year estimates of HT/LD by line of therapy were 21.6% (95% CI: 18.9-24.3), 23.7% (95% CI: 19.9-27.4) and 29.3% (95% CI: 23.3-34.7), respectively. A clinical prediction model was independently developed for each line of therapy; the final model for each line consisted of the same variables: increasing age, male sex, higher LDH, lower hemoglobin, higher white blood cell count, prior immunochemotherapy exposure, and shorter time since initial diagnosis. The parameter estimates for these variables were broadly similar across the different lines of therapy. The model output is an individual patient's risk of HT/LD. Patients with high-risk FLP-R, as defined using the upper quartile of FLP-R risk scores for each line, had observed 5 year HT/LD rates of 43%, 44% and 51% in lines 2-4, respectively. In contrast, patients with the lower quartile of FLP-R risk scores had observed 5 year HT/LD rates of 10%, 6% and 8% in lines 2-4, respectively. The optimism-corrected c-statistic for the FLP-R model across all lines of therapy was 0.685. This added significant information beyond FLIPI diagnosis (c=0.533) FLIPI at index line (c=0.563), the line of therapy (c=0.525), POD24 status (c=0.578), or all 4 variables combined (c=0.614). Conclusions: The FLP-R model identifies a group of patients with non-transformed FL in the R/R setting who are at very high risk of transformation and/or lymphoma-related death across lines of therapy. FLP-R features 4 of the 5 components of the 1L FLIPI24 prediction model (B2M was unavailable for modeling) with the addition of sex, treatment history and time since initial diagnosis. The number of prior therapies is not sufficient to identify high-risk populations for clinical trial enrichment in the R/R FL setting and model discrimination for FLP-R was greatly improved over FLIPI and/or POD24 across lines of therapy. A Shiny app will be provided for model implementation; external validation is planned.

Abstract Background Single-agent R is a common 1st-line therapy for patients (pts) with FL, especially those with low-tumor burden advanced stage disease or comorbidities. EO is a therapeutic vaccine generated from non-self-protein sequences from gut bacteria, including 4 HLA-A2 CD8 T cell epitopes that mimic B cell-specific markers: CD20, CD22, CD37 and BAFF-receptor. EO also contains a CD4 helper epitope UCP2. EO expands pre-existing memory CD8 T cells recognizing non-self-protein sequences from gut bacteria which can cross-react with B cell antigens on tumor cells. The aim adding EO to R is to safely increase the depth and duration of responses. Methods Cohort 3 (C3) of trial EONHL1-20/SIDNEY includes pts with HLA-A2 and previously untreated low-tumor burden (GELF) FL grade 1-3A in need of treatment (per pt/treating physician). Pts receive EO (300μg/peptide) SC with adjuvant Montanide, q2 weeks (w) x 4, then q4w for a total of 12 doses, combined with R starting at w7 (375 mg/m2 IV q1w x4, then q8w x4). For immune responses blood mononuclear cells were assayed by flow cytometry and EO-mimic or B cell peptide specific tetramers without in vitro stimulation. The primary objective is to assess safety; secondary objectives include EO immunogenicity and preliminary efficacy. Results As of July 2025, the 6 planned pts had started EO. Median age was 66 years (range 46-73); 5 ECOG 0/1 ECOG 1; 1 Ann Arbor stage III/5 stage IV; FLIPI low risk 2/intermediate 2/high 2; FLIPI-2 low risk 2/intermediate 4. At median follow-up 10.6 months (mo) 4 pts completed and 2 are ongoing on EO. Median treatment duration was 43 w (range 2-43). Best response by Lugano in the 6 pts included 4 complete (CR) and 2 partial responses (PR). Median time to PR/CR was 17.1 w (range 6.0-18.0). Currently there is only 1 (not yet confirmed) progression at 20.5 mo. All 5 immune response evaluable pts had expansion of CD8 T cells specific for EO mimic and B cell target peptides during treatment; 4 of 5 had detectable expansions at w5 (1st testing time). Currently, the longest tested immune response is at w65 and positive for both EO mimic and B cell target peptides. Expanded specific CD8 T cells had a memory phenotype predominantly composed of effector memory (TEM) cells but also including central memory (TCM) and terminally differentiated effector memory CD8 T (TEMRA) cells. Across the 5 pts, the medians of max % (sum of specific CD8 T cells targeting either the 4 EO mimic peptides or the 4 B cell antigen epitopes at a specific timepoint) among all peripheral CD8 T cells were 0.71% (range 0.19-3.97) for EO mimic and 0.33% (0.20-1.30) for B cell target peptides. The most common EO-related adverse events (AEs) were local administration site reactions (erythema, pain, induration). These included Gr (Grade) 1 reactions in 3 pts, Gr 2 in 1 pt, and Gr 3 in 1 pt; latter being ulceration with EO-interruption at w10.1, and in context of a strong immune response against EO mimic [3.97% of all peripheral CD8 T cells at w5] and B cell target [1.30%] peptides, and CR from w16.7. Other EO related AEs were Gr 1 lymph node pain (1 pt), and related to both EO and R were Gr 2 urticaria (1 pt) and Gr 1 fatigue (1 pt). Only R related were Gr 2 infusion related reaction (3 pts), Gr 2 enterocolitis infection (1 pt), and in 1 pt each Gr 1 flushing, anemia, headache and diarrhea. There were no further Gr 3-4 AE and no death on treatment/follow-up. Complete B cell depletion was seen in 5 pts tested at w18 (R added w7); no recovery in the range of w30-65. Only 3 infections were reported, per above enterocolitis, and 2 cases of COVID-19 both resolved without sequalae. ConclusionsThe combination of EO with R has a predictable and manageable safety profile, with EO only adding local administration site reactions to the well-known R safety profile. In this feasibility cohort all evaluable pts developed a specific immune response against EO and B cell targets, and a Lugano objective response. The combination of EO and R is feasible and can be evaluated in further trials. Updated results will be presented at the meeting.

Abstract Introduction Short diagnosis-to-treatment interval (DTI) is associated with aggressive disease biology and inferior outcomes in diffuse large B-cell lymphoma (DLBCL), and is recognized as a potential source of selection bias in clinical trials if not properly addressed. However, its prognostic significance in follicular lymphoma (FL) remains poorly characterized. We aimed to evaluate the prognostic significance of DTI in newly diagnosed FL patients who received frontline (1L) immunochemotherapy (IC), using a large international dataset and an independent external validation cohort. Methods For the discovery dataset, we evaluated patients diagnosed between 2002 and 2018 from ten observational cohorts as part of the FLIPI24 Consortium. External validation was conducted using data from patients enrolled in the Lymphoma Epidemiology of Outcomes (LEO) Cohort between 2010 and 2015. All patients had FL grade 1–3A and received 1L IC within 100 days of diagnosis. Patients with a concurrent DLBCL were excluded. Missing baseline laboratory values were addressed via multiple imputation. The primary endpoint was event-free survival at 24 months (EFS24); secondary endpoint was 5-year overall survival (OS), both calculated from treatment initiation. DTI was analyzed as continuous (via splines) and dichotomized variable (≤14 vs >14 days; as defined in DLBCL). Results In the discovery cohort (n=3,907), median age was 61 years (IQR 53–69), and 50% were male; 49% of patients were high-risk according to FLIPI, 26% according to PRIMA-PI, and 38% according to FLIPI24. Included patients received R-CHOP (54%), R-CVP (26%), or B-R (20%) as 1L treatment, followed by anti-CD20 maintenance in 60%. The median DTI was 30 days (IQR 17–48). Using the 14-day cut-off, 851 patients (22%) had short DTI. These patients had more adverse baseline characteristics, including B symptoms (42% vs 32%, P<0.01), ECOG performance status ≥2 (15% vs 8%, P<0.01), elevated LDH (51% vs 40%, P<0.01), hemoglobin <12 g/dL (30% vs 17%, P<0.01), and elevated β2-microglobulin (56% vs 44%, P<0.01). Prognostic indices (PIs) were also more frequently high-risk in the short-DTI group: FLIPI (56% vs 47%), PRIMA-PI (36% vs 24%), and FLIPI24 (51% vs 34%, all P<0.01). Spline modeling showed a decreasing EFS24 rate with increasing DTI, reaching a plateau at 30–40 days. In logistic regression model, each additional week of DTI improved EFS24 (OR 0.92, P<0.01). DTI attenuated but remained prognostic after adjusting for PIs (OR 0.93 for FLIPI, 0.95 for PRIMA-PI, 0.96 for FLIPI24, all P<0.01). When analyzed as a dichotomized variable, short DTI was associated with inferior EFS24: OR 1.74 adjusted for FLIPI, 1.63 for PRIMA-PI, and 1.53 for FLIPI24 (all P<0.01). The 2-year EFS of short vs long DTI groups was 71% vs 82% (HR 1.50, 95% CI 1.34–1.67, P<0.01), 5-year OS was 80% vs 86% (HR 1.38, 95% CI 1.21–1.56, P<0.01), and the 5-year cumulative risk of histologic transformation was 7.7% vs. 5.4% (P<0.01). In the validation cohort (n=516), median age was 61 years (IQR 52–69 years), 55% were male; 36% of patients were high-risk according to FLIPI; 29% according to PRIMA-PI, and 33% according to FLIPI24. Patients received B-R (59%) or R-CHOP (41%) as 1L treatment. The median DTI was 31 days (IQR 19–48), 84 patients (16%) had DTI ≤14 days. Similar patterns were observed; patients with short DTI had adverse baseline characteristics, PIs, and shorter 2-year EFS (72% vs 84%, HR 1.69, 95% CI 1.13–2.55, P=0.01). DTI remained associated with EFS24 when analyzed as a continuous variable (per week: OR 0.88 unadjusted, 0.90 with FLIPI, 0.89 with PRIMA-PI, and 0.89 with FLIPI24), and dichotomized (≤14 vs >14 days: OR 1.83 adjusted for FLIPI, 1.88 for PRIMA-PI, and 1.73 for FLIPI24). Conclusion Short DTI, defined as ≤14 days (observed in 22% of FL patients vs 46% in DLBCL), is a strong and independent predictor of inferior outcomes in newly diagnosed FL patients treated with IC. While DTI correlates with adverse baseline features and established PIs, it retains independent prognostic value. Although a 14-day threshold is reasonable for risk modeling, DTI contains greater informational value when modeled as a continuous variable. Among PIs, FLIPI24 most strongly attenuated the DTI effect, underscoring its superior discriminative power over FLIPI and PRIMA-PI. Clinical trials designs should mitigate any potential barriers to enrollment of FL patients requiring urgent therapy.

Abstract Background: Multiple myeloma patients face complex barriers to diagnosis, care access, support, and navigation. This study analyzes patient-reported experiences to identify structural gaps and cluster patients into meaningful segments based on their needs and perceptions. Methods: We administered a 48-item anonymous survey to adult myeloma patients at the Medical College of Wisconsin and through national platforms, including the International Myeloma Foundation, Leukemia & Lymphoma Society, and Facebook groups. The survey assessed demographics, treatment experiences, delays, perceived personalization, and barriers to care. We used JMP 17 for analysis and Julius.AI for visualization. Rule based segmentation of structured responses was used to identify distinct patient personas. Chi-square tests assessed associations, with p < 0.05 considered significant. The study was IRB-approved. Results : A total of 320 participants responded between April 25 and June 5, 2025; 289 (90.3%) completed the survey in full. The cohort was predominantly older (55.7%, n=170/305 between 60- 75), White (79.3%, n=241/304), female (58.9%, n=179/304), highly educated (89.5%, n=272/304), and suburban (52.5%, n=159/303). Modal insurance types were Medicare (37.8%) or private insurance (30.9%); 11.2% both. Most (69.7%) reported a smooth treatment start; delays were primarily due to insurance/cost (4%). Using rule-based segmentation of structured responses, we identified three distinct patient personas: (1) Empowered but Unsupported (n=56; 17.5%) who indicated no emotional support barriers, less interest in navigators, but frequent reports of unmet needs such as poor communication. (2) Engaged and Informed (n=105; 32.8%): Highly motivated patients who requested personalized care, clinical trial transparency, or insurance navigation and (3) Delayed and Discouraged (n=35; 10.9%) who reported lower support, diagnostic delays, and a strong perception of race-related disparities. Unclassifiable personas (n=124) were due to missing or neutral responses There was no difference in self identified race across the personas (p = 0.08), but 100% of the Delayed/ Discouraged group believed race played a role in care, compared with 44% of the Engaged/Informed and 21.4% of the Empowered/Unsupported (p < 0.001). Minoritized patients (86.7% Black, 100% other minoritized) were more likely to perceive race as a factor (p = 0.0024). Empowered/Unsupported patients were significantly more likely to request better communication (100%) and empathy (53.6%), while Engaged and Informed patients prioritized clinical trial access (61%). None of the Delayed and Discouraged patients made this request (p < 0.0001). Black respondents most frequently expressed the need for greater empathy (53.7%; p = 0.0012). Those <60 (40.2%, n=33) were more likely to express interest in clinical trials (p=0.03), this interest did not vary by race (p=0.36). Interest in patient navigation did not significantly differ by education level (p = 0.3), suggesting that even highly educated patients may struggle with treatment complexity. Most patients felt their care was personalized (71.1% 207/291), with no differences by race (p = 0.55), but perceptions varied by persona with only 39.1% of Engaged/Informed patients felt their treatment was always tailored, vs. 61.8% of Empowered/Unsupported and 88.6% of Delayed/Discouraged (p < 0.0001), contrasting patients' expectations with the actual delivery of care. Conclusion: Patient-reported experiences reveal distinct personas with differing needs, perceptions and expectations of care. While most patients reported smooth treatment transitions and felt their care was personalized, gaps persist particularly among highly engaged patients who report unmet expectations around communication, personalization, and trial access. Perceptions of racial disparities persist, especially among minoritized groups illuminating the unequal experiences of patients within the myeloma care landscape. These findings stress the importance of segmenting care approaches to align with patient identity, complexity, and support needs in multiple myeloma.

Abstract Introduction: T-PLL is a rare, aggressive leukemia with poor prognosis and limited therapies. Previous studies on T-PLL patients receiving an allogeneic stem cell transplant (alloSCT) are limited by small numbers with limited data on disease and transplant characteristics. Further, recent data from our large national cohort of patients demonstrated significant survival difference between TCL1A+ and TCL1A- T-PLL, and CD8+ T-PLL vs CD8- T-PLL. In this large multi-center series, utilizing comprehensive disease subtype and alloSCT clinical data, we evaluated prognostic and survival therapeutic outcomes in T-PLL patients that had an alloSCT with a particular focus on T-PLL disease subtypes. Methods: We retrospectively evaluated 572 diagnosed with T-PLL at 21 academic cancer centers throughout the USA between 2000-2023, of which we performed a further evaluation on the169 that proceeded with alloSCT. Overall survival (OS) and progression-free survival (PFS) were assessed using Kaplan-Meier methods and Cox proportional hazard models. Results: Among n=169 alloSCT recipients with T-PLL, the median follow-up time was 20.9 months post-alloSCT (range: 0.2-182.9), the median age at transplant was 59 years (range: 35-77) and 52% were male. In evaluated patients (n=109), TCL1A was positive by cytogenetics or FISH in 69%. As our recent analysis demonstrated significant differences in survival among specific subtypes of T-PLL, we evaluated outcomes in patients with CD4+CD8- T-PLL (n=90, 53%), CD4-CD8+ (n=17, 10%) T-PLL, and CD4+CD8+ T-PLL (n=52, 31%). 53% (87/164) had known nodal involvement at diagnosis identified by PET or CT scan and 45% (43/96) of known patients had minimal residual disease (MRD) at the time of transplant [defined as <5% T-PLL in marrow by flow, or +cytogenetics (e.g. TCL1A)] prior to alloSCT. At the time of alloSCT, 136 (80%) patients were in CR and 23 (14%) patients were in PR. Forty-nine (30%) had a myeloablative (MAC)conditioning regimen and 114 (70%) had a reduced intensity chemotherapy (RIC) conditioning regimen. Eighty (49%) patients had TBI as part of their regimen. The most common regimens were fludarabine (flu)/melphalan based regimens (n=44; 26.0%), flu/cyclophosphamide (cy) based regimens (n=33; 19.5%), flu/busulfan based regimens (n=22; 13.0%), flu/total body irradiation (TBI) (n=8; 4.7%), and cy/TBI (n=4; 2.4%). Across the whole cohort, the median OS and PFS post-alloSCT was 32.6 months (95% CI: 21.0-41.9) and 20.8 months (95% CI: 14.4-30.5) months while the 1-year cumulative incidences (CI) of NRM and relapse were 17% and 20%, respectively. The incidences of grade II-IV acute GVHD and cGVHD were 19% and 23%. There was no difference between patients with myeloablative conditioning (MAC) (n=49, 29%) when compared to patients that received reduced intensity conditioning (RIC) (n=114, 67%) in OS (33.1 vs 29.2; p=0.68) and PFS (20.2 vs 20.8; p=0.97). Patients that were MRD+ (n=31) had worse OS (22.2 vs 48.6; p=0.1) and PFS (14.1 vs 32.5; p=0.04) and higher rates of relapse (1-year relapse 20% vs 8%; p=0.08) than patients that were MRD- (n=50). PFS was improved in those who received alloSCT though only trended towards significance due to low numbers (HR 0.76, p=0.09). In subtype analysis, TCL1A+ T-PLL had significantly worse outcomes compared to TCL1A negative T-PLL. TCL1A+ disease had significantly worse OS (21.6 vs 63.1; p=0.01) and PFS (12.4 vs 50.7; p=0.01) compared to TCL1A-. Additionally, in TCL1A+ disease CI of NRM (24% vs 3%; p=0.02) and relapse (25% vs 12%; p=0.86) was higher vs TCL1A- PLL. CD4+CD8-, CD4-CD8+, and CD4+CD8+ disease had no difference in survival via either OS (28.0 vs 34.4 vs 21.0; p=0.17) or PFS (29.4 vs 23.5 vs 13.6; p=0.09) as well as no difference 1-year CI of NRM ( 11.6 vs 23.5 vs 26.2; p=0.35) and relapse (18.5 vs 23.5 vs 20.0; p=0.67).Conclusions: AlloSCT significantly improved outcomes for patients with T-PLL compared to those who did not proceed to alloSCT and remains he only curative therapy for those with T-PLL. OS, PFS, and CI relapse were significantly worse for patients with TCL1A+ subtype of T-PLL, or those with MRD positivity or PR prior to alloSCT. Novel strategies to decrease relapse such as post-alloSCT maintenance therapy to improve outcomes are urgently needed in these patients.

Abstract Introduction: Hemophagocytic lymphohistiocytosis (HLH) is a rare and life-threatening hyperinflammatory syndrome resulting from immune dysregulation. While diagnostic and therapeutic guidelines (e.g., HLH-2004) are established for pediatric HLH, adult-onset HLH remains both a diagnostic and therapeutic challenge, with limited characterization and sparse outcome data. Here, we conduct a single-institution retrospective cohort study to evaluate clinical features, causes, and prognostic markers associated with outcomes. Methods: We performed a retrospective chart review of all adult patients (≥18 years) first diagnosed with HLH across all Mayo Clinic sites between January 1, 2006 and July 1, 2025. Diagnosis was based on hematologist adjudication at time of care. Patients with prior diagnoses of HLH or HLH related to T-cell therapy (CAR-T) were excluded. Clinical and laboratory variables were extracted from electronic health records. The primary outcome was overall survival (OS), defined as time from diagnosis of HLH to death or last follow-up. OS was estimated using the Kaplan-Meier method. Multivariable analysis to identify independent predictors of mortality was performed using a Cox proportional hazards regression model, adjusting for age at diagnosis, sex, HLH etiology, and relevant clinical and laboratory parameters. Model discrimination was assessed using Harrell's concordance index (c-index). Descriptive statistics were summarized using median and interquartile range (IQR) for continuous variables and frequency with percentages for categorical variables. Results: A total of 203 patients diagnosed with HLH were included. The median age at diagnosis was 55 years (range 18-86). The cohort was predominantly male (n=130, 64%) and White (n=163, 80%). The majority of diagnoses occurred in more recent years, with 75 patients (36.9%) diagnosed between 2021–2025, 61 (30.0%) between 2016–2020, and 43 (21.2%) between 2011–2015. Prior to HLH diagnosis, 86 patients (42.4%) had a history of malignancy, 55 (27.1%) had a history of autoimmune disease, and 28 (13.8%) had a history of transplant. The most common HLH etiologies were malignancy-associated (n=99, 49%), infectious (n=51, 25%), and autoimmune (n=24, 12%), in addition to idiopathic (n=6, 3%), post-transplant lymphoproliferative disease or graft-vs-host disease (n=3, 1%), drug-induced (n=3, 1%), or primary HLH (n=1, 0.5%). The most common malignancies included T-cell (n=35, 17.2%) and diffuse large B-cell lymphoma (n=24, 11.8%). Forty-four cases (21.7%) were associated with Epstein-Barr virus (EBV), either through overt viremia or malignancies with EBV positivity on pathology report. Five patients (2.5%) had COVID-19–associated HLH and 2 (1.0%) were attributed to immune checkpoint inhibitors. Overall, 164 patients (80.8%) met the HLH-2004 diagnostic threshold of ≥5 out of 8 criteria, while 196 (96.6%) met the HLH-2024 ≥4 of 7 modified criteria. Among patients with available information, elevated ferritin was present in 197 of 198 (99.5%), fever in 185 of 202 (91.6%), cytopenias involving ≥2 lineages in 184 of 199 (92.5%), hemophagocytosis in 156 of 182 (85.7%), elevated sCD25 in 117 of 121 (96.7%), hypertriglyceridemia in 117 of 186 (62.9%), hypofibrinogenemia in 118 of 196 (60.2%), splenomegaly in 125 of 188 (66.5%), and impaired NK cell activity in 16 of 25 (64.0%). In addition, hepatomegaly was noted in 57 of 195 patients (29.2%). After a median follow-up of 58.3 months, median OS was 62 days (95% CI 40-110) from day of diagnosis. In a multivariable Cox proportional hazards model with moderate discrimination (c-index=0.75), after adjusting for age at diagnosis and sex, T-cell lymphoma–driven HLH (HR 1.78, 95% CI 1.05–3.00, p = 0.03) and elevated blood urea nitrogen (median 51.0 mg/dL, IQR 27.9–99.1; HR 2.07, 95% CI 1.37–3.13, p < 0.005) were independently associated with shorter OS Conclusions: In this cohort of adult patients with HLH, malignancy was found to be the most common trigger for HLH. T-cell malignancies in particular were strongly correlated with poor survival. Elevated blood urea nitrogen at diagnosis also identified patients at significantly higher risk of death, consistent with other critical illnesses that can present with multi-organ failure. These findings emphasize the need for adult-specific prognostic tools incorporating disease etiology and organ dysfunction markers to better stratify risk and guide clinical management in adult-onset HLH.

Abstract Background and Significance: CMML is a myeloid neoplasm characterized by hematopoietic stem and progenitor cell (HSPCs) monocytic bias, leading to downstream monocyte expansion that plays a key role in disease maintenance and progression. Monocytes in CMML express high surface expression of the homing C-C chemokine receptor 2 (CCR2), which promotes malignant monocyte survival. Expansion of CCR2+ monocytic progenitors drives acute transformation in CMML and contributes to venetoclax resistance in AML. For these reasons, CCR2 is a potential novel therapeutic target in CMML and monocytic AML. The CyTAC platform was designed to enable targeting of cell surface antigens that demonstrate limited or ineffective binding to conventional therapeutic antibodies. A CyTAC is a heterobivalent small molecule that binds to both a target of choice and to a fully humanized monoclonal antibody. STX-0712 comprises a CCR2 CyTAC which potently binds to CCR2 on malignant cells, and a CyTAC humanized ADCC-enabling monoclonal antibody, which when combined eliminates target cells via enhanced effector-mediated killing in the presence of NK cells. We have demonstrated that treatment with STX-0712 ex vivo results in human target engagement and pharmacodynamic activity, and in vivo leads to depletion of CCR2 MO1 monocytes in a potent and dose-dependent manner in CMML and AML (ASH 2024). Therapeutic depletion of CCR2+ malignant monocytes presents a novel opportunity to develop a potential disease-modifying targeted therapeutic agent. We have designed a first-in-human, phase 1 clinical trial to evaluate the effect of CCR2 CyTAC in patients with refractory/resistant CMML, and relapsed/refractory monocytic or monocytic predominant AML. Study Design and Methods This is a phase 1, first-in-human, open-label, multicenter clinical trial based in the USA to evaluate STX-0712 as a monotherapy in patients with CMML and AML who have no remaining treatment options known to confer clinical benefit. STX-0712 will be administered as a single intravenous (IV) infusion every 3 weeks (additional regimen schedules may be explored) until evidence of disease progression, death, intolerance to study medication, or withdrawal of consent. The study consists of a dose-escalation and dose-expansion part and includes two cohorts: Cohort 1 (refractory/resistant CMML) and Cohort 2 (relapsed/refractory monocytic or monocytic predominant AML). Dose escalation will begin in participants with CMML using the Bayesian Optimal Interval (BOIN) design, with a minimum of three patients enrolled at each dose level. Backfilling of up to two cleared dose levels will be initiated once efficacious exposure levels are reached and at least one CMML participant has achieved a complete remission (CR) or a partial remission (PR), marrow response, or clinical benefit as defined by the MDS/MPN IWG 2015 criteria. In the AML cohort, backfilling may begin once at least one participant has achieved a response defined by ELN 2022 criteria. Dose expansion will occur upon completion of dose escalation in each cohort, using a Simon 2-stage adaptive design. Approximately 47 CMML and 58 AML patients may be enrolled in this phase 1 study. The primary objectives of the study are to evaluate the safety and tolerability of STX-0712 and to determine the minimal safe and biologically effective dose, recommended phase 2 dose (RP2D), and/or maximum tolerated dose (MTD), and to characterize dose-limiting toxicities (DLTs). Secondary objectives include evaluation of preliminary antitumor activity, pharmacokinetic (PK) parameters, and pharmacodynamic effects of STX-0712 on CCR2+ malignant cells in blood and bone marrow. Key exploratory endpoints include: (1) assessment of changes in CCR2+ tumor cells following STX-0712 dosing, (2) evaluation of candidate biomarkers, (3) characterization of T cells, B cells and NK cells at baseline and over the course of treatment, and (4) to explore the effects of STX-0712 on patient-reported outcomes using the CMML Symptoms Assessment Tool (MPN-SAF-TSS scoring system) and the EuroQoL 5 Dimension 5 level (EQ-5D-5L) for AML. Enrollment for Cohort 1 (CMML) began in March 2025, and the study is ongoing. Clinical Trial Information: NCT06950034

Abstract Background: Rural/nonmetropolitan (nonmetro) counties face known barriers to comprehensive cancer care compared with metropolitan (metro) counties, which may impact the outcomes for lymphoma patients. We evaluated the impact metro vs nonmetro status on outcomes after a diagnosis of non-Hodgkin lymphoma (NHL) in the context of clinical, demographic, and lifestyle factors. Methods: Of 7724 participants enrolled in the prospective LEO cohort study from 2015-2020, 7610 (98.5%) had their county of residence at diagnosis assigned a RUCC (2013) code. We compared outcomes of participants from metro (defined as RUCC 1-3, which are central counties with ≥1 urban areas of ≥50,000) vs nonmetro counties (RUCC 4-9, which are counties with smaller urban areas as well as completely rural). We estimated hazard ratios (HRs) and 95% confidence intervals (CI) from univariable and multivariable Cox models for associations of metro status with overall survival (OS). Cause of death (lymphoma [including treatment related], non-lymphoma, unknown) was assessed using a competing risk approach. Results: Compared with metro counties (N=6096), LEO participants from nonmetro counties (N=1514) were older (median age 64 vs 62 years; p<0.001), more likely to be non-Hispanic white (94% vs 75%; p<0.001) and married (84% vs 75%; p<0.001), and less likely to have completed graduate or professional school education (16% vs 27%; p<0.001). There were no notable differences (>5%) by metro status for sex, employment status, NHL subtype, stage, performance status, abnormal lactate dehydrogenase (LDH), international prognostic index (IPI), number of comorbidities, time from diagnosis to treatment interval (DTI) or participation in a clinical trial. Compared with LEO participants from metro counties, those from nonmetro counties had inferior OS at 5 years (74.5% vs 78.4%; HR=1.23, CI 1.10-1.37; p<0.001). The OS association only slightly attenuated after adjustment for age, sex, race/ethnicity and NHL subtype (HR=1.20, CI 1.07-1.34; p=0.002), and held in models that adjusted for clinical prognostic factors (stage, NHL subtype, IPI, DTI), socioeconomic status (SES; education, marital status), health status (comorbidity, frailty), or lifestyle factors (smoking, body mass index). Using a competing risk model, the cumulative incidence of death at 5 years due to lymphoma (16.9% vs 14.1%; p=0.002) and non-lymphoma (5.9% vs 3.9%; p=0.002) was higher for participants from nonmetro vs metro counties, respectively. For participants <65 years, nonmetro vs metro status had inferior OS (HR=1.40, CI 1.17-1.67; p<0.001). This association remained after adjustment for age, sex, race/ethnicity and NHL subtype (HR=1.36, CI 1.14-1.63; p<0.001), as well as after adjustment for clinical prognostic, SES, health status, or lifestyle factors. The cumulative incidence of death at 5 years due to lymphoma was higher in participants from nonmetro vs metro counties (15.1% vs 11.5%; p=0.002), while there was no difference by metro status for non-lymphoma related deaths (2.1% vs 1.7%; p=0.47). In contrast, for participants age 65+ years, there was no differences by metro status for OS (HR=1.04, CI 0.91-1.20; p=0.56). After adjustment for age, sex, race/ethnicity and NHL subtype, participants from nonmetro areas had inferior OS (HR=1.12, 0.97-1.29) although this was not statistically significant (p=0.13), and was attenuated in models adjusting for clinical, health status, or lifestyle factors. The cumulative incidence of death at 5 years due to lymphoma was no different in participants from nonmetro vs metro counties (18.9% vs 18.0%; p=0.37), while non-lymphoma related deaths were higher in nonmetro counties (9.9% vs 6.8%; p=0.017). Conclusion: LEO participants from nonmetro vs metro counties had inferior OS overall, although this was predominately observed for younger (<65 years) participants. These associations did not appear to be explained by demographic, NHL subtype, clinical, SES, health status, or lifestyle factors. Of particular note, the risk of death due to lymphoma was higher in nonmetro areas for participants <65 years but not those 65+ years, while the risk of death due to other causes was higher in nonmetro areas for participants 65+ years but not those <65 years. These findings require further study, particularly related to barriers to care, and suggest the potential need for age-specific strategies to optimize outcomes for NHL patients from nonmetro/rural areas.

Abstract BACKGROUND Hereditary hemorrhagic telangiectasia (HHT) is the second most common inherited bleeding disorder (IBD) worldwide, afflicting 1 in 5,000 people. HHT is likely the most morbid IBD of women. Severe, recurrent epistaxis, gastrointestinal (GI) bleeding, and solid organ arteriovenous malformations (AVMs) cause major clinical and psychosocial morbidity and reduced survival. In recognition of the serious morbidity of HHT as an IBD, in 2022 the U.S. Congress allocated funding to create CHORUS, the Comprehensive HHT Outcomes Registry of the United States (NCT06259292). Herein, we present the initial report from CHORUS. METHODS CHORUS is a prospective, multicenter, U.S. longitudinal registry enrolling unselected patients with HHT, collecting over 2400 data elements. Data were collected by trained research coordinators at enrollment and follow-up visits via the medical record and direct participant interviews. RESULTS Patients. 600 patients with genetically- or Curacao criteria-confirmed HHT were enrolled from November 2023 to April 2025 at 15 U.S. HHT Centers of Excellence. Median (range) age was 53 (0-88) years, and the cohort was 60% female. Despite most patients developing typical HHT disease manifestations by age 13, most HHT diagnoses (63%) were made during mid-to-late adulthood. Mucosal Bleeding. 568 patients (95%) developed recurrent spontaneous epistaxis, with 339 (60%) developing recurrent epistaxis prior to age 13; 43% had at least one nasal surgery/procedure and 22% had at least one medical therapy (e.g., antifibrinolytic or antiangiogenic) for epistaxis. 180 (30%) had a known diagnosis of chronic GI bleeding. Among post-menarche females, 124 (34%) had been diagnosed with heavy menstrual bleeding. 247 (41%) reported other clinically significant mucocutaneous oral or skin bleeding. 454 (76%) had developed moderate-to-severe HHT-associated mucocutaneous bleeding, defined as an Epistaxis Severity Score >4, bleeding requiring targeted pharmaceutical or surgical intervention, IV iron, and/or red cell transfusion. This includes 334 (56%) with moderate-to-severe HHT-associated epistaxis. CNS and Pulmonary Hemorrhage. 16 patients (3%) suffered one or more intracranial hemorrhages (ICH), with 10 (63%) suffering a first ICH by age 25. 13 (2%) suffered one or more pulmonary hemorrhages. Iron Deficiency and Anemia. 408 patients (68%) had been diagnosed with anemia (351, 59%) or iron deficiency (381, 64%). Of those, 247 (61%) and 150 (37%) required IV iron and RBC transfusion, respectively. Solid Organ AVMs. Brain, pulmonary, and liver AVMs were diagnosed in 81 (15%), 268 (45%), and 128 patients (21%), respectively. Just 30 with brain AVMs (37%) had these diagnosed by age 25. 3 patients (2%) had undergone liver transplantation. Thrombosis. Venous and arterial thromboembolism occurred in 44 (7%) and 38 patients (6%), respectively, including 34 (6%) with ischemic stroke (94% of whom had pulmonary AVMs). Other Serious HHT Complications. These included heart failure in 41 patients (7%), pulmonary hypertension in 44 (7%), chronic liver disease in 17 (2.8%), epilepsy in 24 (4%), severe bacterial/deep-seated tissue infection in 35 (6%), and brain abscess in 15 (3%). 205 (34%) developed migraine. Notably, serious CNS manifestations of HHT (brain AVM, ischemic stroke, intracranial hemorrhage, and/or epilepsy) occurred in 128 (21%). 241 (40%) required emergency room visits and/or hospital admissions specifically to manage HHT complications. CONCLUSIONS This first-of-its-kind HHT registry reliably describes for the first time the incidence and severity of numerous HHT complications. Most patients develop moderate-to-severe recurrent epistaxis and/or chronic GI bleeding as well as iron deficiency anemia (usually requiring IV iron and/or RBC transfusion). Heavy menstrual bleeding, thromboembolism, severe cardiopulmonary complications, and serious CNS complications are all substantially more common in HHT than previously thought. Notably, ICH occurred in 3% of patients, which approximates the ICH incidence of hemophilia in the pre-factor prophylaxis era and is ~2-fold and ~9-fold higher than in hemophilia A treated with modern factor prophylaxis (1.6%) and modern non-factor prophylactic agents (0.3%), respectively, per the ATHN registry. This 3% number may be an underestimation given the known high ICH mortality rate, pervasive delay in HHT diagnosis, and the fact that survival post-ICH is necessary to enroll in CHORUS.

Abstract Background Patients with myeloproliferative neoplasms (MPNs) are at risk of splanchnic vein thrombosis (SVT). Prior studies failed to demonstrate a benefit of hydroxyurea in preventing SVT extension/recurrence, but these were limited by small sample sizes and inability to account for starting, stopping, or switching of cytoreductive therapies. We therefore investigated the role of cytoreduction as a time-dependent covariate on thrombosis recurrence in a large, international cohort of MPN-SVT patients. Methods We performed a retrospective cohort study of MPN-SVT patients included in the international GASTRO-MPN consortium. Patients diagnosed with MPN at any time before, concurrently with, or up to 60 days after initial SVT were included. Primary outcome was time from initial SVT to first thrombosis recurrence, defined as the composite of SVT extension/recurrence, transjugular intrahepatic portosystemic shunt (TIPS) thrombosis, or venous/arterial thrombosis outside the splanchnic veins. Secondary outcomes included SVT extension/recurrence, TIPS thrombosis or extra-SVT thrombosis individually, clinically relevant bleeding (composite of major and clinically relevant non-major bleeding), MPN progression to myelofibrosis or blast phase, and death. Cytoreductive therapy was treated as a time-dependent covariate to account for discontinuation and therapy changes. Multivariable Cox proportional hazard models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CI). Results A total of 757 patients were included for this analysis. Median age was 51 years (IQR 38-62), 59% were female. SVT involved the portomesenteric veins in 558 (77%) patients, hepatic veins in 95 (13%), and both in 54 (7.4%). MPN was known prior to initial SVT in 316 patients (42%) and diagnosed concurrently or up to 60 days after SVT in 441 (58%). Polycythemia vera (PV) was the most common MPN subtype (43%), followed by essential thrombocythemia (ET) in 24%, and primary myelofibrosis in 14%. JAK2V617F mutation was present in 86% and CALR in 2.9%. 13% had prior non-SVT thrombosis. 607 patients (83%) were treated with cytoreduction. At time of SVT, 131 patients (17%) were already on cytoreduction; in those who started after SVT, median time to initiation was 54 days after SVT, and median duration of cytoreduction per patient was 63 months. Cytoreductive therapies used at any point in treatment included hydroxyurea in 504 (69%), ruxolitinib in 182 (25%), and interferon-based in 85 (12%) patients. Anticoagulation (AC) was started within 30 days after SVT in 504 (68%) patients. Median duration of any AC per patient was 24.6 months. During a median follow up of 7.4 years, 245 patients (33%) had thrombosis recurrence; 143 (20%) had SVT extension/recurrence/TIPS thrombosis, 129 (18%) extra-SVT thrombosis (of which 74% venous), 237 patients (32%) experienced clinically relevant bleeding, and 163 (22%) died. After adjusting for age, sex, timing of MPN diagnosis relative to SVT diagnosis, AC within 30 days of SVT, PV/ET vs other MPN, JAK2 mutation, previous thrombosis, non-MPN cancer, and cirrhosis, cytoreductive therapy was associated with a significantly decreased risk of recurrent thrombosis (HR 0.67 95%CI 0.50-0.89, p=0.01). Age was associated with an increased risk of recurrent thrombosis (p=0.01). When considering types of recurrent thrombosis, cytoreduction was associated with a decreased risk of SVT extension/recurrence/TIPS thrombosis (HR 0.62 95%CI 0.42-0.90, p=0.01), but not thrombosis outside the splanchnic veins (HR 0.97 95%CI 0.72-1.30, p=0.82). There was no association between cytoreduction and bleeding (HR 1.10 95%CI 0.82-1.47, p=0.52). Similarly, there was no association between cytoreduction and time to MPN progression (p=0.24) or overall survival (p=0.30). In a subgroup of patients without erythrocytosis/thrombocytosis at initial SVT (n=271), cytoreductive therapy was associated with a HR 0.65 (95%CI 0.40-1.10, p=0.09) for recurrent thrombosis. Limited sample size and low event-rate precluded evaluation of the impact of individual cytoreductive therapies. Conclusions In the largest cohort of MPN-SVT patients to date, we show for the first time that cytoreductive therapy is associated with a decreased risk of thrombosis recurrence, driven largely by decreased SVT extension/recurrence/TIPS thrombosis. Collectively, these findings support use of cytoreductive therapy in individuals with MPN-SVT to prevent recurrent thrombosis.