Citations

Abstract Introduction: Primary central nervous system T-cell lymphoma (PCNSTL) is a rare form of PCNSL, comprising 2–8% of cases. Prognostic factors remain undefined, and no standard treatment protocol currently exists. Prior studies have been limited by small sample sizes, incomplete molecular profiling, and poor representation of novel treatment modalities. In this study, we aimed to identify clinicopathologic factors associated with patient (pt) outcomes and delineate the spectrum of treatment regimens used to inform future clinical practice. Methods A multicenter retrospective study was conducted across 15 North American academic institutions. Pts aged ≥18 years with biopsy-confirmed PCNSTL between 2009 and 2025 with no evidence of systemic disease were included. Cases with CNS relapse of systemic T-cell lymphoma were excluded. Baseline characteristics were analyzed using independent t-tests, Fisher's exact tests, or Pearson's chi-square tests. Primary endpoints were overall survival (OS) and progression-free survival (PFS), evaluated by Kaplan–Meier, log-rank tests, and Cox regression. Results: Forty-two pts met inclusion criteria. Median age was 57 (range 19–77), 69% were male, and 79% were white. Most (69%) had ECOG 0–1. No patients had HIV, hepatitis B or C, or a history of solid organ transplant. LDH was elevated at diagnosis in 38%, and 24% had B-symptoms. Mean absolute lymphocyte count at diagnosis was 1.82/µL. The most common histologic subtypes were PTCL-NOS (76%), followed by ALK-negative ALCL (12%) and γδ T-cell lymphoma (5%). All patients had parenchymal brain lesions with 57% having multifocal disease. Additionally, CSF involvement was seen in 21%, vitreoretinal involvement in 3%, and deep brain involvement in 34%. Next-generation sequencing was performed in seven pts (17%), with disease-associated variants identified in three cases. Among these, two pts had mutations in TP53, and one had a mutation in DNMT3A. Cytogenetics were obtained in 7 pts with only one exhibiting a complex karyotype. Only one pt was EBV positive by EBER-ISH. Overall, 79% received HD-MTX-based therapy. First-line treatments were mainly HD-MTX alone (38%), HD-MTX + temozolomide (17%), or vincristine + procarbazine (12%). No patients were treated on clinical trials. Median treatment duration was 78 days and median number of treatment cycles was 4 (range 1–9 cycles). One patient received radiation alone; 5% received radiation with systemic therapy. A steroid pre-phase was used in 60%, with 44% exhibiting a clinical response. Overall response rate to first-line treatment was 63% (13 CR, 12 PR). Imaging alone was used in determining response in all patients. Repeated biopsy was not performed. Twelve patients (29%) underwent consolidative autologous transplant, most commonly with thiotepa/carmustine (TT/BCNU, 69%) or BEAM conditioning (25%). Median duration of follow-up was 10.4 months. Sixty-two percent of pts progressed during the study period, with 7% experiencing extra-CNS relapse. Median PFS was 8.2 months. Improved PFS was associated with >3 cycles of therapy (p=0.03) and transplant with TT/BCNU (p=0.0004). At last follow-up, 43% were in remission and 52% were deceased, mostly due to disease progression (77%). Median OS was 17.6 months. One- and two-year OS rates were 58% and 42%, respectively. OS was associated with Nottingham/Barcelona score <2 (p=0.02), >3 treatment cycles (p=0.0008), response to first-line therapy (p=0.0007), and TT/BCNU-based transplant (p=0.0001). IELSG, Taipei, and MSKCC risk scores were not significantly associated with survival, though IELSG approached significance (p=0.09). Discussion: This study is among the largest cohorts of PCNSTL pts compiled to date. PCNSTL remains rare and heterogenous. Treatment across centers largely mirrors management of B-cell PCNSL with high utilization of HD-MTX regimens and TT/BCNU conditioning autologous transplant. Survival outcomes within our cohort are consistent with those previously reported within the literature. Receipt of >3 cycles of therapy, TT/BCNU conditioning and Nottingham/Barcelona scores were associated with longer survival within our cohort. Limitations of our study include its retrospective design and heterogeneity within pt disease characteristics, treatments utilized and disease assessment intervals. Further exploration into pathophysiology and optimal management of this unique entity is needed.

Abstract Background and Significance: Polycythemia vera (PV) is a myeloproliferative neoplasm associated with pathologic erythrocytosis, most often driven by somatic mutations in the JAK2 gene. A key treatment goal is maintaining hematocrit (HCT) below 45% to reduce thromboembolic complications. Current standard of care for patients diagnosed with PV, including phlebotomy (PHL) and cytoreductive therapies (CRT), can be burdensome, may lead to intolerable adverse effects, and often are associated with symptoms of iron deficiency. DISC-3405 is an investigational, novel, humanized immunoglobulin (Ig)G1 monoclonal antibody that targets transmembrane serine protease 6 (TMPRSS6, also known as matriptase 2) to stimulate endogenous production of hepcidin, a peptide hormone secreted by hepatocytes and the key regulator of iron homeostasis. In a randomized, placebo-controlled study in healthy volunteers (DISC-3405-101), DISC-3405 administered subcutaneously at doses between 37.5-300 mg was well-tolerated, resulted in dose-dependent pharmacokinetic (PK) profiles, significantly increased hepcidin production with corresponding reductions in serum iron levels, and reduced HCT (Liu et al, EHA 2025, PS2207). DISC-3405 is being developed as a potential treatment for patients with PV requiring HCT reduction, regardless of baseline risk or concurrent CRT. Study Design and Methods: This is a multi-center, open-label, 52-week Phase 2 study enrolling up to 20 patients with PV in the United States to assess the safety, tolerability, PK, pharmacodynamics (PD), and therapeutic effect of DISC-3405 on PV disease control as evidenced by HCT reduction and PHL requirements. After an observation period of 4-12 weeks, participants will be treated and followed for 52 weeks and dosed up to 300 mg every 2 weeks. After 52 weeks, participants can continue in an optional 2-year continuation phase where long-term safety and efficacy will continue to be assessed. The main efficacy endpoints of the study include the proportion of participants achieving therapeutic response, defined as absence of PHL eligibility; number of PHLs during the treatment period; and proportion of participants with HCT values <45% throughout the study. PHL eligibility is defined as (1) HCT ≥45% and ≥3% (absolute change) of pre-treatment values or (2) HCT >48%. Eligible participants include adults 18 or older who meet the 2022 World Health Organization diagnostic criteria for PV. Clinically acceptable laboratory values include HCT <45% prior to Day 1 (dosing) or HCT <48% if followed by a PHL within 2 weeks prior to first dose of study drug, white blood cells 4000/μL to 20,000/μL (inclusive), and platelets 100,000/μL to 1,000,000/μL (inclusive). Participants should have at least 3 PHL in 26 weeks or 5 PHL in the 52 weeks prior to screening, and at least 1 PHL within 12 weeks prior to screening. Participants receiving CRT must have been on the therapy for at least 6 months and on a stable PV treatment regimen, including hydroxyurea, interferon, or ruxolitinib, for at least 2 months. Participants treated with only PHL must have stopped CRT 6 months before screening. Key exclusion criteria include participants that require PHL at HCT levels <45%, clinically significant thrombosis within 2 months prior to study treatment, active or chronic bleeding, estimated glomerular filtration rate of <30 mL/min/1.73 m2, and history of invasive malignancies within the last 5 years, except localized cured prostate cancer and cervical cancer, or other malignancies deemed acceptable in discussion with the Sponsor. The study will enroll participants from approximately 15-20 sites in the United States. Additional details can be found at https://clinicaltrials.gov/study/NCT06985147.

Abstract Introduction: Indolent systemic mastocytosis (ISM) is a clonal mast cell disease driven by the KIT D816V mutation in ~95% of cases and is associated with symptoms of mast cell activation and tissue infiltration. It can cause chronic, debilitating symptoms − including life-threatening anaphylaxis and impaired bone health. While historically most patients have relied on symptom-directed best supportive care (BSC) therapies, avapritinib is used as a new standard of care targeting KIT D816V, the primary driver for SM. Avapritinib is an oral, potent, selective KIT D816V inhibitor, and the first and only approved targeted therapy for adult patients with ISM in the USA and the EU. Approval was based on results from the phase 2 PIONEER trial. Here, we present the findings from ~3.5-year long-term follow-up. Methods: Adults with centrally confirmed ISM and uncontrolled moderate-to-severe symptoms who completed the randomized dose-finding (Part 1), or randomized, double-blind, placebo-controlled (Part 2) portions of PIONEER (NCT03731260) rolled over to the open-label, long-term extension (Part 3). This cumulative analysis includes patients who initiated avapritinib at the recommended dose of 25 mg once daily (QD) in either Parts 1, 2, or 3. All patients received BSC. Per investigator discretion and based on disease burden, dose titration up to 50 mg QD of avapritinib was permitted in Part 3. Long-term efficacy was assessed by measuring changes in symptoms and QoL, using the ISM-Symptom Assessment Form (ISM-SAF; ©2018 Blueprint Medicines, a Sanofi Company) and the Mastocytosis Quality-of-Life Questionnaire (MC-QoL). Safety was also assessed. Results: Overall, 226 patients initiated avapritinib 25mg QD across Parts 1, 2, and 3. This longer-term analysis is inclusive of 65 patients who dose titrated from 25 mg to 50 mg QD in Part 3. Median (range) treatment duration was 40.0 months (0.7‒67.2) as of February 21, 2025. Longer-term efficacy data with ~3.5 years of follow-up demonstrated sustained disease-related symptom improvements. The mean change (standard deviation [SD]) in total symptom score (TSS, per ISM-SAF), was −19.80 (19.81) at Week 144 (Month 33) and −20.43 (20.57) at Week 168 (Month 39) from a baseline of 48.08 (19.47). Additionally, avapritinib-treated patients demonstrated durable improvement in their most severe symptoms (mean change [SD] from baseline of −3.35 [3.02] at Month 33 and −3.47 [3.19] at Month 39) per ISM-SAF. Sustained responses were observed across all individual symptom domains (0–30) with mean changes (SD) at Month 33 and Month 39 of −3.77 (5.52) and −3.84 (6.05) for the gastrointestinal domain, −8.21 (7.70) and −8.20 (7.85) for the skin domain, and −4.66 (6.24) and −4.87 (6.51) for the neurocognitive domain. The mean percent change (SD) in MC-QoL was −34.67 (40.16) at Month 33 and −40.72 (33.24) at Month 39 from a baseline of 54.24 (18.32). Treatment with avapritinib was well tolerated, and its safety profile was similar to the previously reported placebo-controlled portion. Most treatment-related adverse events (TRAEs) were Grades 1–2, and 7% of patients experienced Grade ≥3 TRAEs of which diarrhea, neutrophil count decrease, and weight increase occurred in >1 patient. No Grade ≥3 TRAEs of increase in transaminases were observed. Edema (peripheral and periorbital), the most frequently reported TRAE, was mostly Grade 1 and occurred most frequently during the first 3–4 months of treatment. Three patients (1%) experienced serious adverse events assessed as treatment related. However, none led to treatment discontinuation and no trends were observed. After approximately 3.5 years of follow-up, low rates of treatment discontinuations (n=7, 3%) due to TRAEs were observed. Conclusion: Longer follow-up of patients with ISM treated on the PIONEER trial, including some on avapritinib for up to 5 years, demonstrates that prolonged avapritinib therapy continues to be effective and well tolerated. Additional prospective analyses will be needed to determine effects of selective KIT D816V-inhibition on anaphylaxis. These data support a favorable benefit-risk profile of avapritinib as a chronic treatment for adult patients with ISM.

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: In R/R DLBCL/FL, T-cell engager therapy (TCET) using chimeric antigen receptor T-cell therapy (CART) or bispecific antibodies (BsAbs) are promising options. Patients (pts) with R/R disease post TCET experience dismal outcomes with overall survival (OS)< 5 months (mos). Lonca, an antibody drug conjugate (ADC) targeting CD19 (FDA approved for R/R DLBCL and beneficial in R/R FL) has been increasingly used post-TCET. RWDA of Lonca is limited, especially regarding: 1) impact of CD19 expression on activity, 2) adverse events (AEs) in non-clinical trial setting, and 3) impact of sequencing Lonca and TCET. Thus, we conducted a RWDA of Lonca efficacy and toxicity in R/R DLBCL and FL pre- and post-TCET. Methods: We conducted a multicenter retrospective study of R/R DLBCL or FL pts ≥18 years who received Lonca from 2017 to 2025 at 10 US academic sites. Demographic, pathological, treatment, and AEs were collected. Efficacy outcomes included overall response rate (ORR), complete response (CR), partial response (PR), stable disease (SD), and progressive disease (PD). Progression-free survival (PFS) and OS were analyzed by Kaplan-Meier method. CD19 expression by immunohistochemistry (IHC) and/or flow cytometry (FC) prior to Lonca administration was correlated to outcomes. Results: Among 120 pts (DLBCL n= 101, FL n=19), all but 2 pts received Lonca monotherapy. At a median follow-up of 6.1 mos, median PFS and OS were 2.6 mos and 6.7 mos, respectively for the entire cohort. For DLBCL, median age was 66 years (18-89). Median prior lines of therapy (LOT) were 4 (1-11). ORR was 37.7% (CR: 17%, PR: 20.7%), SD: 6%, and PD: 56%. Median PFS was 2.1 mos, and median OS was 5.8 mos. For FL, median age was 62 years (28-88). Median prior LOT was 6 (2-8). ORR was 49.4% (CR: 28%, PR: 21.4%), SD: 14%, and PD: 35.7%. Median PFS was 6.7 mos, and median OS was 6.8 mos. OS by best response (entire cohort) was 11.3 mos and 11.8 mos in those who had CR and PR, respectively, 10.6 mos in SD and 3.5 mos in those with PD. Lonca LOT (2nd-12th line) was not associated with improved OS (p=0.58). Bulky disease (>7.5 cm) was not associated with worse OS (p=0.07). PD to Lonca was associated with PD at 2nd line treatment (OR: 4.3; 95% CI: 1.7–10.9) and 3rd-line treatment (OR: 4.2; 95% CI: 1.5–11.5), elevated lactate dehydrogenase (OR: 1.9; 95% CI: 1.2–2.9), and each subsequent increase of extranodal sites >1 prior to Lonca (OR: 1.5; 95% CI: 1.04–2.1). Among pts with available CD19 status prior to Lonca administration, 28 were FC-positive and 22 were IHC-positive. Of the CD19 FC-positive pts (n=23), 22% (5/23) achieved CR, 26% (6/23) had PR, 8% (2/23) had SD, and 43% (10/23) developed PD. Of the CD19 IHC-positive pts (n=20): 15% (3/20) achieved CR, 20% (4/20) had PR, 5% (1/20) had SD, and 60% (12/20) developed PD. Among all CD19-negative pts (n=7), two achieved CR, one had SD, and four with PD. Any grade AE was seen in 84% of pts. Any grade ≥3 (G3) AE was seen in 62% of pts. Notable G3 AEs included: anemia (35%), lymphopenia (34%), neutropenia (21.6%), thrombocytopenia (20%), infection (17%), fatigue (9%), peripheral edema (5%), pleural effusion (4%), photosensitivity (2.5%), and pruritus (2.5%). Treatment discontinuation due to AEs occurred in 17% (n=21) of pts. Fifty-five pts (50 DLBCL, 5 FL) received both Lonca and CD19 directed CART (Pre-Lonca n=54; Post-Lonca n=1). There was no significant difference in PFS or OS between pts who received CART and those who did not (PFS: 2.7 mos vs 3 mos; OS: 7.4 mos vs 5 mos). BsAb was used in 41 pts (34 DLBCL, 7 FL) (Pre-Lonca n=30; Post-Lonca n=11). No significant difference in PFS or OS was observed between pts who received BsAb pre- or post-Lonca. There was also no significant difference in PFS between pts who received a BsAb (2.2 mos) and those who did not (2.9 mos), nor in OS.Conclusion: In this large RWDA of Lonca, pts who achieved any form of clinical response experienced a significantly longer OS than previously reported for heavily pre-treated pts. Lonca was predominantly administered after TCET; however, there was no significant difference in efficacy between pts who received CART and BsAbs and those who did not. CD19 positivity and earlier utilization of Lonca did not appear to have an impact on response rates. Our findings support a role for Lonca in the treatment of R/R DLBCL pts not candidates for TCET. This RWDA highlights the need to further investigate the sequencing of Lonca in R/R DLBCL and FL.

Abstract Background: Recent advances in computer vision have given rise to image foundation models (FMs), large-scale neural networks pre-trained on millions of unlabeled histopathology patches, which can learn generalizable representations of tissue morphology. In many cancers, these FMs have predicted genetic mutations and prognoses directly from histology, suggesting that morphology encodes “hidden” molecular information. In lymphoma, this field is nascent but growing.General-purpose histopathology FMs have limited representation of lymphoid morphology. We developed and evaluated LymphoVision, a lymphoma-specialized image foundation model pretrained with self-supervised learning, to extract clinically meaningful features from routine hematoxylin and eosin (H&E) histology. Methods: LymphoVision was pre-trained using knowledge distillation and consistency (DINOv2) on over 37 million multi-resolution patches (5x, 10x, 20x, 40x) sampled using a density-aware strategy from 31,211 H&E whole slide images (WSIs) from 9,155 archival lymphoma and reactive lymphoproliferative cases. To ensure diverse, representative samples, our patch sampling method uses an efficient graph-based clustering algorithm and prioritizes morphologically informative regions by clustering patch embeddings and performing density sampling within each cluster. The pretrained encoder was evaluated using a clustering-constrained attention multiple instance learning (MIL) framework on three diagnostic tasks: (1) cell-of-origin (COO) classification in diffuse large B-cell lymphoma (DLBCL), distinguishing germinal center B-cell (GCB) from non-GCB subtypes based on the Hans immunohistochemistry algorithm; (2) follicular lymphoma (FL) grading, differentiating low-grade (grades 1–2) from high-grade (grade 3); and (3) multiclass lymphoma subtype classification across six categories: DLBCL, FL, marginal zone lymphoma (MZL), mantle cell lymphoma (MCL), classical Hodgkin lymphoma (CHL), and benign/reactive lymphoid conditions. WSI-level labels were derived from pathology reports, and none of the evaluation cases were included in pretraining. Models used a ViT-Giant LymphoVision backbone to generate 20x patch embeddings, followed by MIL using 50% training data and 2-fold cross-validation (25% validation, 25% test). Performance was assessed using area under the receiver operating characteristic curve (AUC), accuracy, recall (sensitivity) and F1 score. Results: For DLBCL COO classification (total n=358 cases), LymphoVision achieved a mean test AUC of 0.93 (range 0.92–0.94), accuracy of 84.5% and F1 of 0.85 across two independent test folds (n=91 per fold, 50% GCB). These results outperformed general-purpose FMs on the same task and cases, including Virchow-v2 (AUC 0.85) and UNI-v2 (AUC 0.88), despite those models being pretrained on 10–100 times more images. For FL grading (total n=660 cases), the test set in each fold included 166 cases (18% grade 3), yielding a mean test AUC of 0.88 (range 0.87–0.90), accuracy of 89.2% and F1 of 0.80. In multiclass lymphoma subtype classification (total n=1,176 cases), the test set included 296 cases per fold. LymphoVision achieved a mean test AUC of 0.98 (range 0.97-0.99), mean test accuracy of 87.1% and mean F1 of 0.84. Class-wise recall was 92.0% for DLBCL (n=112), 88.2% for FL (n=72), 77.2% for MZL (n=29), 70.8% for MCL (n=35), 87.5% for CHL (n=24), and 95.8% for benign/reactive lymphoid conditions (n=24). Conclusion: LymphoVision is a lymphoma-specialized FM trained using self-supervision that achieves high diagnostic accuracy across multiple clinically meaningful tasks using weak supervision and standard H&E images, suggesting the encoder has learned fine-grained lymphoma morphology. Based on historical benchmarks from the 1997 International Lymphoma Study Group classification project, expert hematopathologists achieved diagnostic agreement rates of 55% to 84% using H&E morphology alone for the non-Hodgkin lymphoma (NHL) entities included in our multiclass task. LymphoVision approached or exceeded these benchmarks. These findings underscore the value of our approach using disease-specialized pretraining and intelligent patch sampling for data-efficient histopathology learning. LymphoVision has the potential to augment diagnostics, enable scalable AI-powered classification in real-world workflows, and serve as a foundation for prognostic and theragnostic applications. External validation and multimodal integration are ongoing.

Abstract Diffuse Large B Cell Lymphoma (DLBCL), the most common subtype of aggressive B-cell Non-Hodgkin Lymphoma (NHL), accounts for 30-40% of newly diagnosed NHL cases. Despite recent progress improving our understanding of molecular features of DLBCL, there is still a high relapse rate (~45%) among patients who undergo standard treatment (R-CHOP). Several groups have identified reproducible molecular clusters of DLBCL although, the biologic significance of many of the specific gene mutations within these clusters is poorly understood. DTX1 mutations are a feature of the BN2/C1 DLBCL classifiers and are among the mutations with unknown significance. BN2/C1 DLBCL are a mixture of ABC, GCB, and Unclassified cell of origin (COO) with a common signature being the presence of genetic alterations in genes known to regulate the NOTCH pathway; yet, these tumors lack transcriptional signatures of traditional NOTCH activation, suggesting a unique and undefined biology driven through non-canonical NOTCH pathway activation. DTX1 is an E3 ubiquitin ligase which directly binds the intracellular domain of the NOTCH receptor (NICD), targeting it for degradation, resulting in suppression of NOTCH pathway activity. We therefore hypothesize that DTX1 mutations lead to NOTCH pathway dysregulation and are a critical driver for a subset of BN2/C1 DLBCLs. Using whole exome sequencing (WES) data from 404 newly diagnosed DLBCL patients, we found 8% of patients with mutations in DTX1. Alterations in DTX1 were localized to the NICD binding domain, WWE1. In silico Alphafold modeling of DTX1 WWE1-interaction with NICD revealed that patient mutations clustered within predicted interacting surfaces with NICD. These findings lead to the hypothesis that mutations in the DTX1 WWE1 domain suppress its ability to bind to and degrade NICD, enhancing NOTCH pathway activation in DLBCL. To address this question, we first compared DTX1 protein expression by immunoblot in DTX1 WWE1 mutant (OCI-Ly3 and SUDHL2) and wildtype (WT) (OCI-Ly7, OCI-Ly19, SUDHL6, and U2932) DLBCL cell lines. We found higher expression of NICD1 (p=0.03) in OCI-Ly3 and NICD2 (p<0.0001) in SUDHL2 cell lines compared to WT. This increase was accompanied by an increase in NOTCH surface expression with higher NOTCH1 (p<0.0001) and NOTCH2 (p<0.0001) expression on OCI-Ly3 and SUDHL2 cells, respectively, compared to WT. To remove variability across cell lines we next used CRISPR to generate DTX1 knock out (KO) models using WT DTX1 DLBCL cell lines U2932 and OCI-Ly19. Analysis of NICD and NOTCH receptor protein expression confirmed our initial finding, showing an 8.5 and 4.8-fold increase of NICD1 and a 6 and 2.5-fold increase of NICD2 expression in the U2932 and OCI-Ly19 DTX1 KO cell lines, respectively, compared to empty vector (EV) controls. An increase in surface NOTCH1, and to a lesser extent NOTCH2, was seen in U2932 (p=0.01 and p=0.07, respectively) and OCI-Ly19 (p=0.001 and p=0.2, respectively) KO cells compared to EV controls. To identify pathways affected by DTX1 mutations, we next performed RNAseq on U2932 EV and KO cell lines. Of interest, we did not detect any significant changes in classical NOTCH driven genes (Hes1, Hey1, etc.), supporting prior studies on BN2/C1 tumors. However, we did identify potential non-canonical NOTCH-target genes that may contribute to lymphomagenesis. Gene expression in KO cells showed upregulation of genes involved in germinal center (GC) processes (AICDA, IRF4; p<0.001) and cellular growth and survival (IL6R, CCND2, STAT5B, BCL2; p<0.0001). Measurement of IL6R by flow cytometry and CyclinD2 by immunoblot further verified DTX1-mediated upregulation of IL6R (p<0.01) and CyclinD2 (p<0.01) for U2932 KO cells compared to EV control. We also observed downregulation of genes contributing to cell death (ex. BAX, CASP8, FAS; p<0.05) in KO cells compared to EV. Together, these novel findings support our hypothesis that DTX1 WWE1 mutations lead to dysregulation of the NOTCH pathway by driving overexpression of NICD and NOTCH, resulting in dysregulated expression of proteins involved in cell cycle, GC reaction, and apoptosis. We further provide new biologic insight into BN2/C1 DLBCL, ultimately highlighting a path toward novel therapeutic targets and the advancement of personalized medicine, as patients harboring these mutations may benefit from new therapies targeting inflammatory pathways, such as CELMoDs.

Abstract Background: Given a potential risk of extravasation with vesicants and irritants, central venous catheters (CVCs), such as port-a-cath or peripherally inserted central catheters (PICC), are commonly used for the administration of anthracycline-based chemotherapy. However, CVC placement can result in treatment delay, deep vein thrombosis (DVT), catheter malfunction, and added burdens (eg, financial, travel, etc), partly due to the need for regular flushing. Peripheral intravenous (PIV) access is often utilized in the academic setting with select frontline chemotherapy regimens. However, there is limited data reporting on the safety of PIV in this setting. This large, multicenter RWA evaluated the use and associated complications of PIV and CVC for administering CHOP- or ABVD-based chemotherapy in patients (pts) with lymphoma. Methods: We conducted a retrospective RWA across 8 U.S. centers among pts aged ≥18 years with non-Hodgkin lymphoma and Hodgkin lymphoma who were consecutively treated with ABVD or CHOP-based anthracycline chemotherapy via PIV or CVC access between 2010-2024. Choice of catheter placement was at the discretion of the pt's treating physician. Detailed baseline and safety data were collected. The primary outcome was extravasation; secondary outcomes included infiltration, DVT, cellulitis, erythema, and pain. Standard definitions of extravasation and other complications were used (Jackson-Rose J. CJON 2017). Rates of complications were compared via Fischer exact testing. Results: A total of 1,414 pts were included in the analysis: 790 in each arm (ie, PIV vs CVC). Of these, 624 were unique to each group, while 166 pts received chemotherapy via both modalities (PIV and CVC during the treatment course). Overall, 78.9% of pts completed all treatment as planned via PIV. Median age was 63 years (IQR 45–75) in the PIV group and 61 years (IQR 40–73) in the CVC group. Male sex comprised 57% vs 51%, ECOG 0–1 performance status was 83% vs 76%, and advanced-stage disease (stage III/IV) was present in 51% vs 62%, respectively. Lymphoma subtypes were comparable: DLBCL/high-grade/B-cell NOS (54.5% vs 56.1%), Hodgkin lymphoma (27.2% vs 27.5%), T-cell lymphoma (12.4% vs 6.6%), and indolent/mantle cell lymphoma (5.6% vs 6.7%). Among those receiving chemotherapy via CVC, 78.5% were treated through a port-a-cath and 21.5% via PICC. CHOP-based and ABVD-based regimens were administered to 68% and 32% of PIV pts, and 69.6% and 30.4% of CVC pts, respectively. A total of 4,084 (PIV) vs 3,859 (CVC) treatment cycles were delivered, corresponding to 4,347 (PIV) vs 4,884 (CVC) anthracycline infusion days. There was 1 documented case of extravasation in the CVC group and 2 suspected cases in the PIV group (p=0.9); for PIV, this translates to a per pt risk of 0.3% (or 0.05% of infusion days). The two PIV cases involved elderly women with DLBCL receiving CHOP. Both developed localized symptoms post-infusion and were treated conservatively (DMSO/warm compresses or dexrazoxane/ice), with full symptom resolution within 1 week and 1 day, respectively. No tissue or vascular injury occurred. Additionally, there were no significant differences between the PIV and CVC groups in the rates of induration/swelling (1.8% vs 2.0%, p=0.85), phlebitis/cellulitis (2.4% vs 2.4%, p=0.9), venous thromboembolism (VTE; 1.4% vs 2.0%, p=0.32), or erythema (3.8% vs 5.1%, p=0.27). Pain or tenderness at the infusion site (8.5% vs 2.9%, p=0.001) and infiltration (1.4 vs 0.13%, p=0.006) were more frequent in the PIV group. Chronic vascular complications related to prior VTE was slightly lower in the PIV group (0.13% vs 0.9%, p=0.06), but not significant. Additional details from a propensity score-matched analysis will be presented at the meeting. Conclusions: This is the largest known analysis to date evaluating the safety of PIV access for anthracycline-based chemotherapy in >1,500 lymphoma pts over a recent 15-year period, representing >9,000 total treatments with CHOP or ABVD. PIV access was found to be safe and associated with a low rate of serious complications. Moreover, extravasation was rare and there was not a significant difference observed between PIV and CVC use. While PIV use was associated with higher rates of local pain/tenderness and infiltration, the events were uncommon and self-limited. Despite the widespread default to CVC placement in many centers, these findings support the selective use of PIV in appropriate pts as elucidated here.

Abstract While the clinical focus on the sentinel lymph node biopsy (SLNB) is the presence of intra- or extra-nodal metastases, preclinical studies suggest that tumor-draining SLNB-associated vascular architecture and adhesion properties are altered regardless of SLNB positivity. Human intravital microscopy (HIVM) has defined blood vessel abnormalities that may impact lymphocyte adhesion and systemic drug delivery at primary melanoma sites. In this pilot study of HIVM during melanoma SLNB, we sought to determine the feasibility of obtaining HIVM observations of SLNB-associated vessels. We successfully performed HIVM in all 20 SLNB patients, and 7 were found to have nodal micrometastases by standard pathology. HIVM was capable of identifying both functional and non-functional SLNB-associated vessels based on the presence or absence of fluorescent dye uptake, respectively. Comparing vessel characteristics as a secondary objective, no statistically significant differences were noted in the diameter, flow rate, functionality, or shear stress of SLNB-associated blood vessels between positive and negative SLNBs, which may likely have been a reflection of the minimal disease burden. Nonetheless, these initial observations provide the framework to optimize future trials of HIVM in cancer patients.