Aggressive B-cell Lymphoma Research Articles

The KIR-HLA-CD16a Immunogenetic Profile Influences NK Cell-Mediated ADCC and Response to Rituximab Therapy in B-Cell Lymphomas

Rituximab-based chemoimmunotherapy (R-CHOP) is the standard of care in most B-cell lymphomas, however there is marked interpatient heterogeneity in treatment response. An important mechanism of Rituximab (anti-CD20) action is through natural killer (NK) cell-mediated antibody-dependent cellular cytotoxicity (ADCC), but the factors influencing this are poorly understood. Here, we present findings from a preclinical study investigating the role of NK cell receptor polymorphisms and HLA allelic variation on ADCC against aggressive B-cell lymphoma cell lines. Genotyping was conducted using Luminex-based SSO and Sanger sequencing. Multicolor flow cytometry was used to assess the response of activated NK cells from healthy donors against 8 lymphoma cell lines. Individuals carrying the GG or GT allele in CD16a were found to have a 3-8 fold greater NK cell response compared to individuals with a TT allele and rituximab-mediated ADCC was significantly greater in individuals with a KIR-3DL1 allele when tested against B-cell lymphomas lacking the HLA-Bw4 allele. An additive effect was observed when considering both CD16a and KIR-HLA together. As expected, CD20 expression was a strong correlate of NK cell response. In summary, NK cell-mediated ADCC in response to ADCC appears to be influenced by the KIR-HLA-CD16a genotype. These findings suggest a potential role for immunogenotyping in B-cell lymphomas treated with Rituximab. Additionally, the presence of the shared F c receptor domain opens the possibility of applying this framework towards predicting NK cell responses to antibody therapies in other diseases.

Patterns of Care and Prognostic Modeling Following Follicular Lymphoma Transformation to Aggressive B-Cell Lymphoma: An Analysis from the LEO Consortium

Introduction: Histologic transformation (HT) from follicular lymphoma (FL) to an aggressive lymphoma is infrequent but has unfavorable outcomes. Sarkozy et al. (J Clin Oncol, 2019) reported that approximately half of FL-related deaths within the first decade of diagnosis occurred following HT. Our recent analysis showed heterogeneous outcomes with median overall survival (OS) of 61 months (Day et al., ASH, 2022). Prognostic tools post HT would be clinically useful but development has been limited by small cohort sizes. Factors previously associated with outcomes following HT have included age, time to progression, prior therapy, anthracycline exposure, and early HT. Utilizing the Lymphoma Epidemiology of Outcomes (LEO) Consortium of Real World Evidence (CReWE), we describe patterns of care and evaluate other prognostic factors following HT. Methods: This multicenter observational cohort consists of prospectively enrolled patients in the LEO Cohort, and patients with HT retrospectively identified at LEO centers. Patients diagnosed with biopsy proven grade 1-3A FL at diagnosis, and a subsequent biopsy showing HT to an aggressive lymphoma (FL grade 3B, diffuse large B cell lymphoma [DLBCL], or high-grade B cell lymphoma [HGBCL]) between 2002-2022, were eligible for the study. Patients with a component of FL grade 3B, DLBCL, or HGBCL at diagnosis were excluded. HGBCL was defined as double or triple hit or another aggressive subtype. OS was defined as the time from HT until death from any cause and calculated via Kaplan-Meier. Associations between clinical factors at time of HT and/or diagnosis and OS were evaluated using Cox models. Cause of death was evaluated using a competing risk approach. Results: Overall, 328 patients were confirmed with HT during the study period, 41% were female, and the median age at HT was 63 years (interquartile range [IQR] 56-70). The median time from diagnosis to transformation (TDT) was 35 months (IQR 12-66). At HT, 88% had advanced stage disease (III-IV) and LDH was elevated in 49%, while few patients exhibited B symptoms (5%) and ECOG performance status was >2 in 9%. 23% did not receive systemic therapy prior to HT. For those with prior therapy, the median time from prior therapy to HT was 15 months (IQR 7-39). The most frequent treatment regimens following HT were CD20-CHOP (42%), followed by platinum-based salvage therapy (20%), R-EPOCH (10%), CD20-Benda (8%), R-Mono (4%), and R-Gem-Ox (3%). 50 (15%) patients underwent consolidation with autologous stem cell transplant, 3 underwent allogeneic transplant (30 platinum-based, 15 CD20-CHOP, 5 R-EPOCH, 3 Other), and 2 received CAR T-cell therapy (Figure 1). After median follow-up of 85 months from HT, 170 patients had died; 5-year OS was 52% and median OS was 65 months (95% CI: 55-107). Among 160 patient deaths, cause was most often lymphoma-related (progression, n=107 [63%]; therapy-related, n=14 [7%]) compared to non-lymphoma (n=20, 13%) or missing/unknown causes (n=29, 17%). Clinical factors at the time of HT that were associated with worse OS include: ECOG PS >2, age ≥70, IPI 3-5, and shorter TDT (<24 months), hemoglobin <10 g/dl and elevated LDH. A transformation to HGBCL was also associated with inferior OS (Table 1). OS did not significantly differ by gender, BMI, stage, presence of B-symptoms, absolute lymphocyte count, number of extranodal groups, presence of bulky disease at HT, or response to prior FL treatment. Factors at the time of FL diagnosis that were associated with decreased OS after HT included FLIPI score 3-5 (high risk), FLIPI 2 (moderate risk), and FL grade 3A at diagnosis. Exposure to any systemic therapy for FL prior to HT was associated with shorter OS, with the worst outcomes in patients receiving an anthracycline prior to HT. POD24 to frontline immunochemotherapy was associated with inferior OS after HT (Table 1). Conclusions: Patterns of care in Transformed FL are heterogeneous and vary greatly in intensity. These data confirm previous reports that age, early HT, and any systemic therapies prior to HT are negative prognostic indicators for OS. At HT elevated LDH, low hemoglobin, POD24 status, poor performance status, and HT to HGBCL were associated with poor outcomes following HT. These data provide a basis for future prognostic indices to identify patients with highest risk of lymphoma related mortality for whom study of novel treatments is greatly needed.

Impact of Deployment on Survival in Military Personnel with Non-Hodgkin Lymphoma

Introduction: It is estimated that approximately 3.5 million active duty service members (ADSM) have deployed to Afghanistan and Iraq from 2001-2022. There has been concern about potential exposure to carcinogenic or environmental hazards during overseas deployment. A recent study found ADSM with no prior deployments had an increased risk of cancer mortality compared to those who had served in Operation Iraqi Freedom/Operation Enduring Freedom. Moreover, Nordic personnel with military deployments were also found to have a lower risk of cancer related death when compared to the general population. While there may be a link between potential environmental exposures, there is a lack of data on non-Hodgkin lymphoma (NHL) survival in servicemembers who have previously deployed. Additionally, there are no studies comparing risk of aggressive B-cell lymphoma in these patient populations. Methods: Documented cases of NHL in the DoD's Tumor Registry (Oncolog) from 2001-2022 were obtained. This information was compared to the Defense Manpower Data Center's deployment data and the two datasets were merged. ADSMs and retirees were included; dependents were excluded. A multivariable logistic regression analysis was done to assess the impact of prior deployment on cancer survival in NHL, accounting for age, race, cancer stage, ethnicity, and gender. Results: There were 2,295 servicemembers and retirees diagnosed with NHL from 2001-2022. About 20% had previously deployed (n=467). Median age at diagnosis in those who had deployed was 35 years compared to 54 years for non-deployed (p<0.001). Race, ethnicity, and gender were similar between both arms. Multivariable logistic regression analysis demonstrated prior deployment was associated with better survival after accounting for age, race, stage, ethnicity, and gender (OR 0.63, 95% CI 0.40-0.97, p=0.037). In addition to deployment status, other variables that influenced survival were age (OR 1.04, 95% CI 1.03-1.54, p<0.001), stage (OR 2.92 for stage IV vs. stage I, 95% CI 2.06-4.15, p<0.001), and race (OR 1.97 for black vs. white race, 95% CI 1.37-2.83, p<0.001). To assess whether NHL subtype played a role in these findings, a post-hoc analysis was performed on patients with B-cell NHLs, revealing that ADSM with prior deployment were equally likely to have indolent and aggressive subtypes of B-cell NHL as ADSM who had never deployed. Among personnel with prior deployment, 29.6% and 70.4% had indolent and aggressive B-cell NHLs respectively, compared to 32.9% and 67.1% amongst those who never deployed (p=0.25). Conclusions: Military personnel with NHL who had previously deployed lived longer than those with no prior deployment, even after adjusting for age differences between the two cohorts. These findings are not attributable to B-cell NHL subtype (i.e. deployed personnel did not have more indolent NHLs than non-deployed personnel). These results highlight the healthy deployer effect, in which ADSM who are deployable are required to meet minimum fitness standards, undergo a physical health assessment, and do not have disqualifying comorbidities. This study did not evaluate whether an overseas deployment is associated with an increased risk of NHL, but it does appear to provide evidence that potential deployment-related exposures do not appear to alter the biology or subtype of B-cell NHLs. Disclaimer: The contents of this publication are the sole responsibility of the author(s) and do not necessarily reflect the views, opinions or policies of the Department of Defense (DoD) or the Departments of the Army, Navy, or Air Force. Mention of trade names, commercial products, or organizations does not imply endorsement by the U.S. Government.

Impact of Diagnosis to Treatment Interval on Outcomes in Patients with Newly Diagnosed Marginal Zone Lymphoma - a US Multisite Study

Introduction Diagnosis to treatment interval (DTI) is an important prognostic factor in patients with newly diagnosed diffuse large B-cell lymphoma (Maurer M et al, JCO 2018) and mantle cell lymphoma (Epperla N et al, Blood Adv 2023) where patients with shorter DTI consistently show inferior survival. In marginal zone lymphoma (MZL), the use of first-line bendamustine and rituximab (BR) therapy may enhance progression-free survival (PFS) compared to cyclophosphamide-based regimens such as RCHOP/RCVP. However, the differences in outcomes may be influenced by other factors, such as the DTI, especially in observational studies. Until now, the prognostic significance of DTI in MZL has not been explored. Therefore, our objective was to assess the impact of DTI on outcomes for patients with newly diagnosed MZL. Methods This is a substudy of a previously reported multicenter, retrospective cohort that included adult MZL patients treated at 10 US medical centers on or after 1/1/2010. In this substudy, we included patients who initiated first-line BR, RCHOP, or RCVP within 120 days of diagnosis. Patients who were on observation or received antibiotics, local therapy (surgery or radiation therapy), or rituximab monotherapy were excluded. DTI was defined as the number of days from the MZL diagnosis to the start of immunochemotherapy (IC). Using concordance statistics for different DTI cutoffs, we determined 60 days as optimal for analysis. Patients who received treatment within 60 days from their diagnosis were classified into the short DTI group. To compare clinical characteristics between the two groups, univariable and multivariable (MV) logistic regression analyses were performed, accounting for missing data through multiple imputations. The primary endpoint of this analysis was PFS, while secondary endpoints included overall survival (OS) and the cumulative incidence of histologic transformation (HT). Predictors of PFS and OS were identified using Cox regression analysis. Results Of the 900 patients with newly diagnosed MZL included in the main study, 177 patients met the inclusion criteria and were included in this analysis, including 144 (81%) in the short DTI group and 33 (19%) in the long DTI group. The median time to treatment initiation was 27 days (range: 1-60) for the short DTI group and 81 days (range: 61-112) for the long DTI group. The median age was 61 years with 43% EMZL (n=77), 38% NMZL (67), and 19% SMZL (33) patients. Among the patients, 75% received BR as first-line treatment followed by R-CHOP (15%), and R-CVP (10%). A higher proportion of patients in the short DTI group had B symptoms compared to long DTI group (27% vs 3%, p=0.03, respectively). No significant differences were observed between the two groups in regard to MZL subtype, ECOG performance status, stage, LDH, or the choice of first-line IC. In the MV model, presence of B symptoms remained significantly associated with short DTI (OR=12.63, p=0.02). Short DTI was not associated with a statistically different PFS in a univariable assessment (HR=0.86, 95%CI=0.47-1.56), or in the MV model, adjusting for other prognostic factors (aHR=0.87, 95%CI=0.47-1.61, p=0.65, Figure 1A), while high LDH (aHR=2.07, 95%CI=1.06-4.07, p=0.034) and low albumin (aHR=2.31, 95%CI=1.10-4.85, p=0.027) at diagnosis were associated with significantly inferior PFS in the MV model. Additionally, the MV model indicated that patients who received BR had significantly better PFS compared to those who received R-CHOP/RCVP (aHR=0.50, 95% CI=0.29-0.86, p=0.01, Figure 1B). Short DTI was not associated with inferior OS in either univariable or MV models (MV: aHR=0.74, 95%CI=0.26-2.08, p=0.57). There were 12 transformation events in the study: 8 in the short DTI group and 4 in the long DTI group. The cumulative incidence of HT was not significantly different between the two groups (10-year CIF 13% versus 12%, respectively, p=0.22). Conclusion In MZL, a short DTI does not correlate with an inferior prognosis, despite being associated with certain unfavorable characteristics such as the presence of B symptoms. This lack of prognostic utility of DTI in newly diagnosed MZL, in contrast to aggressive B-cell lymphomas, may be intrinsically linked to the underlying biology of the disease. Furthermore, the observed improvement in PFS with BR compared to RCHOP/RCVP, as demonstrated in clinical trials like STiL and BRIGHT, cannot be attributed to differences in DTI.

Anti-PD-1 Antibody (Tislelizumab) Combined with R-CHOP for the Treatment of Previously Untreated Primary Mediastinal B-Cell Lymphoma: A Prospective Phase II Study

Background: Primary mediastinal B-cell lymphoma (PMBCL) is a rare aggressive B-cell lymphoma of thymic origin. Due to the low incidence rate of PMBCL, there is currently no internationally accepted standard first-line treatment regimen. Dose-adjusted (DA) EPOCH-R which is the more commonly used first-line therapy plan is not so effective because patients usually cannot tolerate it. The R-CHOP regimen is comparable to the R-DA-EPOCH for the first-line treatment of PMBCL in terms of survival and has a better safety profile (Bhatt, V.R. et al, Cancer Treat Rev 2015; Iwanicka el al., Curr Hematol Malig Rep 2014). Meanwhile, patients with PMBCL usually have alterations of 9p24.1, leading to overexpression of PDL-1/2. Previous studies have found that PD-1 monoclonal antibody shows good efficacy in recurrent and refractory PMBCL (Steidl et al., Blood 2011; Zinzani et al., Blood 2017). Tislelizumab, a humanized IgG4 antibody that binds PD-1 with high affinity, minimizes binding to Fcγ receptor 1 (FcγRI) on macrophages by the genetic engineering of Fc segment, abrogating antibody-dependent phagocytosis (ADCP)-induced T-cell clearance. The efficacy and safety of its combination with R-CHOP in previously untreated PMBCL is not yet clear. We speculate that the combination of both may be a new option for the first-line therapy for PMBCL patients with good efficacy and low toxicity. Methods: This is a single-arm, multi-center, phase II clinical study (ChiCTR2100044313). Patients aged 18 years or older with a diagnosis of PMBCL and previously untreated were eligible. Eligible patients received 6 cycles of Tislelizumab (200 mg D1), Rituximab (375 mg/m 2 D1), Cyclophosphamide (750 mg/m 2 D2), Pirarubicin (50 mg/m 2 D2), Vincristine (1.4 mg/m 2, maximum dose 2 mg, D2), Prednisone (100 mg/d D2-6), every 21 days for 1 cycle. Disease response assessments were performed by positron emission tomography and computed tomography (PET-CT) or enhanced CT every two cycles, meanwhile peripheral blood ctDNA was monitored, and treatment-related adverse effects were assessed and recorded. The primary endpoint was objective remission rate (ORR). The secondary endpoints included treatment safety, progression-free survival (PFS) and overall survival (OS), and the exploratory analyses of the correlation between PD-L1 expression in tumor tissues, tumor-associated macrophages (TAM) phenotype in tumor microenvironment and efficacy. Results: From June 2020 to June 2023, 12 patients were enrolled and 9 patients had evaluable efficacy with the median age of 34 years, 3 males and 6 females, all patients had large mediastinal mass at initial diagnosis. 7 patients had PD-L1 expression (VENTANA SP263) above 80% and 2 cases could not be further tested due to insufficient tissue specimens. The ORR was 100%, and the CR rate was 77.8% (7/9) after 6 cycles of treatment. The 5 th and 9 th patient reached PR after 6 cycles of treatment due to irregular hospitalization. And CR was achieved after 2 cycles of regular treatment for the 5 th patient. NGS from formalin-fixed paraffin-embedded (FFPE) and circulating tumor DNA (ctDNA) evaluation from blood were performed across all patients before treatment. 5 patients underwent end of treatment-ctDNA test. Median follow-up 15m (6.8m-26.3m), the third patient was lost to follow-up at 9m. The other patients who achieved CR are still at complete remission. Moreover, we found SOCS1, TNFAIP3 are the most frequently mutated genes in biopsies of PMBCL and only the 5th patient had RHOA mutation which is highly related to PMBCL. The PET-CT and ctDNA assessments were negative in three patients at the end of 6 cycles with 60% concordance, and the 5 th and 9 th patient achieved PR on PET-CT, but the ctDNA assessments were negative. The most common adverse events (AEs) were gastrointestinal reactions, 2 patients experienced grade IV myelosuppression and 1 patient had grade I hyperthyroidism. No treatment-related deaths occurred. Conclusion: Tislelizumab combined with R-CHOP for the treatment of previously untreated PMBCL had good efficacy and sustained response with low toxicity. Longer follow-up is required to access the survival benefit of this regimen. Figure 1: Disease Remission in the Included Patients

Phase II, Single-Center, Prospective Study of Intrathecal Thiotepa for the Prophylaxis of Secondary Central Nervous System Involvement in Highly Aggressive B-Cell Lymphoma

Background Central nervous system (CNS) recurrence of systemic diffuse large B cell lymphoma (DLBCL) is a well-recognized and almost uniformly fatal complication that tends to occur within 2 years of initiating treatment. The probability of CNS relapse in DLBCL ranges from 4 to 7% overall but is increased to 20% in certain subgroups. Evidence supporting the use of intravenous methotrexate (MTX) or arabinoside (AraC) in high-risk patients is growing, however, the use of other agents remains to be defined. Thiotepa (TT) is a polyfunctional alkylating agent first developed in the 1950s. Both thiotepa and its metabolite tepa demonstrate good CNS bioavailability, making thiotepa a useful adjunctive chemotherapy for primary and secondary CNS lymphoma, particularly in the context of hematopoietic stem cell transplant (HSCT). Herein, we conduct this prospective trial to evaluate the efficacy and safety of prophylactic intrathecal thiotepa for the prevention of secondary CNS involvement in patients with DLBCL. Methods Patients The primary end point is 2-year cumulative incidence of CNS. The secondary end points are 2-year progression free survival (PFS), 2-year overall survival (OS), and safety. The main inclusion criteria include: adults patients ≥18 years old; histopathological confirmed DLBCL without previous antitumor therapy; high-risk CNS involvement (one of the following): primary breast or testicular lymphoma, involvement of any of the following organs: testis, breast, kidney, adrenal gland, paranasal sinus, epidural space or uterus; CNS International Prognostic Index (CNS-IPI)≥4; dual protein expression (DE) or double/triple hit (DH/TH) lymphoma. The main exclusion criteria include: Burkitt lymphoma, primary CNS lymphoma, or large B cell lymphoma transformed from indolent lymphoma; the presence of parenchymal or meningeal lymphoma; history of whole brain radiotherapy or craniospinal cord irradiation; obstructive hydrocephalus patients requiring neurosurgical intervention. Treatment protocol The systemic chemotherapy regimen is determined by investigator. All patients are need to receive IT thiotepa 10 mg and dexamethasone 5 mg on day 1 of each cycle of chemotherapy for at least 4 cycles. All patients are asked to lie flat for 4 to 6 hours after the lumbar puncture. Follow-up Routine biochemical and cytological analysis of cerebrospinal fluid is performed for each cycle. Imaging examination, such as brain magnetic resonance imaging (MRI) and body computed tomography (CT), is repeated every 2 cycles of chemotherapy, then every 3 months during follow-up. Results From February 2022 to June, 2023, 27 patients (female 14, male 13) received IT thiotepa. The clinical characteristics are shown in Table 1. The median age was 66 years old (range: 46-74). As first-line chemotherapy, 15 (55.6%) patients received rituximab, cyclophosphamide, doxorubicin, vincristine, prednisone (RCHOP), 5 (18.5%) patients received RCHOP+BTK inhibitor, 3 (11.1%) patients received BTK inhibitor, lenalidomide with rituximab (ZR2) followed by RCHOP, and 4 (14.8%) patients received RCHOP with intravenous MTX. Thirteen (48.1%) patients had IPI score 4-6 and 17 (63%) patients had DE of c-myc and bcl-2. All patients received fluorescence in situ hybridization (FISH) cytogenetic testing for C-MYC, BCL-2, BCL-6 and TP53. Four (14.8%) patients had TP53 deletion, and 11 (40.7%) patients had sole rearrangement of C-MYC or BCL-2 or BCL-6, but no one were diagnosed with DH/TH lymphoma. All patient have received IT thiotepa for at least once, and 12 (44.4%) patients completed 4-6 cycles of IT, 84 cycles totally. IT thiotepa was a safe measure, for no one experienced post-LP headache, local infection, bleeding, or cerebral herniation. But there were 4 patients had five times of inability to identify direction and slow speech response. They could recover normally the next day without any treatment. Although the follow-up period was short, no patient developed CNS involvement. Conclusion Prophylactic intrathecal thiotepa is an effective and side-effects manageable measure for preventing secondary central nervous system involvement in high-risk DLBCL. Longer follow-up and larger-scale prospective trial is needed to testify this measure.

Double/Triple Hit Lymphoma Descriptors and Clinicopathologic Determinants of Survival: Analysis of a Pooled Database

Background B-cell lymphoma with MYC, BCL2, and/or BCL6 rearrangements is classified as double/triple-hit lymphoma (DTHL). They usually, but not always, tend to be high-grade aggressive B-cell lymphoma with a worse prognosis. Despite this classification, DTHL remains a heterogeneous group with varied molecular profiles, biological behaviors, and prognoses. Therefore, we conducted this pooled database analysis to identify the prognostic factors, clinicopathological characteristics, and therapeutic strategies influencing survival in this rare disease. Methods To study the demographic characteristics, molecular and immunohistochemical signatures, therapeutic interventions, survival, and prognostic factors, we compiled a pooled database of 161 cases that fit the diagnostic criteria for DTHL. Kaplan-Meier survival curves were constructed. Cox proportional hazards model and Log-rank tests were used to assess the influence of demographic and clinicopathologic factors on overall survival (OS) and disease-free survival (DFS). Results We compiled a dataset of 161 patients with confirmed DTHL. The median age was 62, with an F:M of 1.08. The median duration of symptoms before diagnosis was 2 months. DTHL involved the lymph nodes (41%), bone marrow (31%), bone (14%), CNS (5%), skin (4%), liver (3%), and spleen (2%). Constitutional symptoms were reported in 20% of cases. The cohort consisted of primary (50%), secondary/transformed (16%), and follicular DTHL (34%). The median OS and DFS of the cohort were 69 and 27 months, respectively. Bone marrow and extra-lymphatic organ involvement were associated with worse DFS and non-significant numerically worse OS. LDH>500 (p=0.006), PAX5-negative (p=0.01), CD79a-negative (p=0.02), and Ki67>80% (p<0.0001) were associated with worse OS. Similarly, CD5+, CD10+, and MUM1+ had worse OS but did not reach statistical significance. Follicular DTHL was associated with the best median OS and DFS, followed by primary, then secondary/transformed in decreasing order. Advanced stage and high IPI were also associated with worse non-significant numerical OS. Age and sex did not impact OS. Compared to no treatment, chemotherapy and stem cell transplant had incrementally superior median OS (3 vs. 55 vs. NR months, p=0.008). Frontline intensive chemotherapy yielded similar DFS and OS to CHOP-like regimens. Patients who attained CR as their best response also had a superior median OS (p<0.0001). Conclusion This study presents clinicopathologic data from a cohort of patients with primary, secondary, and follicular DTHL. It identifies the type of DTHL, IHC profile, LDH levels, type of therapy, and quality of response to treatment as critical determinants of OS. Depending on the type (de novo, secondary, or follicular), DTHL seems to behave like 3 different disease entities.

Differing Inflammatory Profiles and Survival Outcomes of Cytokine Storm Arising from CAR T-Cell Therapy, COVID and Malignancy-Associated HLH in Patients with Hematological Malignancies

Background: Cytokine storm is a complex syndrome driven by hyperinflammation leading to multi-organ dysfunction and high mortality rates. Patients with hematological malignancies are susceptible to different types of cytokine storm syndromes (CSS) including those driven by their disease (e.g., malignancy-associated hemophagocytic lymphohistiocytosis (MA-HLH)), treatment toxicities (e.g., cytokine release syndrome (CRS) related to CAR-T) or infections (e.g., COVID associated cytokine storm). The precise nature of the inflammatory mechanisms of different CSS and their impact on clinical outcomes are poorly understood. Methods: We conducted a retrospective study to compare the inflammatory marker profiles and survival outcomes of three CSS: CAR-T CRS, MA-HLH and COVID-CS. The cloud-based Foundry platform was used to aggregate and integrate data from patients with hematological malignancies admitted at the MD Anderson Cancer Center between March 2020 and November 2022. Patients in the CAR-T CRS and MA-HLH cohorts met ASTCT Consensus Grading criteria and HLH-2004 criteria respectively. While there are no well-established diagnostic guidelines for COVID-CS, patients in the COVID-CS cohort had laboratory values higher than the upper limit of normal for at least two of C-reactive protein (CRP), Interleukin 6 (IL-6) or Ferritin within 28 days of COVID diagnosis (Table 1). Biomarker datasets were analyzed through regression models and feature selection to determine inflammation patterns across the three cohorts. Survival outcomes were compared across the cohorts and tested for association with biomarkers to determine their prognostic relevance (Figure 1). Results: A total of 671 in-patients met inclusion criteria across the three patient cohorts: CAR-T CRS (220), MA-HLH (224) and COVID-CS (227). The proportions of different disease types differed among the cohorts (Table 1) with aggressive B-cell lymphomas representing the largest group in the CAR-T CRS cohort (62%) whereas leukemia was the most frequent diagnosis in the COVID-CS (45%) and MA-HLH (38%) cohorts. While fever and fatigue were common presenting symptoms of all 3 CSS, the frequencies of more severe symptoms such as hypotension and capillary leak syndrome were increased in patients with MA-HLH. The median length of hospitalization differed significantly (p < 0.001) across the cohorts: MA-HLH (24 days), CAR-T CRS (15 days) and COVID-CS (6 days). The MA-HLH cohort had the highest proportion of patients requiring ICU admissions and the highest levels of inflammatory markers such as D-dimer, ferritin, IL-6, IL-2 soluble receptor and TNF-alpha and the lowest levels of fibrinogen and albumin. Clustering analysis of laboratory values revealed substantial overlap in patterns between the COVID-CS and CAR-T CRS cohorts, but the MA-HLH cohort was a more distinct cluster. Patients with CAR-T CRS had significantly longer survival (p < 0.0001) than either COVID-CS (hazard ratio 3.7) or MA-HLH (hazard ratio 8.1); MA-HLH patients had the shortest overall survival (Figure 1). These differences were robust after adjusting for differences in baseline demographics. Univariate regression modelling revealed many of the laboratory values to be significantly associated with survival; multivariable analysis found ferritin, LDH and platelet count to be the most significant predictors. Administration of tocilizumab did not improve survival in COVID-CS or MA-HLH. Conclusions: In this retrospective, single-institution study of 3 different types of CSS, we observed that patients with hematological malignancies exhibit different symptom patterns at clinical presentation, have differing inflammatory biomarker profiles and experience variable clinical outcomes depending on the underlying etiology of the CSS. Patients with CAR-T CRS had significantly better survival outcomes compared to those with COVID-CS and with MA-HLH; the latter group had the worst outcomes among the 3 cohorts. This study provides insights into the hyperinflammatory profiles of different CSS in patients with hematological malignancies and highlights the need for developing effective treatments to improve patient outcomes.

Comparative Transcriptome Analyses in Mantle Cell Lymphoma (MCL): Evidence of E2F1 As a Major Target in Aggressive Blastoid MCL Model

Background Mantle cell lymphoma (MCL) is a highly aggressive B-cell lymphoma characterized by the translocation t(11;14)(q13;q32) which triggers the dysregulation of the cyclin D1 by placing its coding gene CC1ND1 under the control of an immunoglobulin promoter. One of the major consequences of this molecular event is the disturbance of the cyclin D/Rb pathway leading to Rb inactivation and activation the elongation factor E2F1 mainly implicated in cell cycle progression. The mainstay of MCL therapies remains the chemo-immunotherapy followed by autologous transplantation but recently several novel therapies have been developed such as BTK inhibitors, Venetoclax, CDK4/6 inhibitors and more recently CAR-T therapies. However, patients with aggressive forms of MCL exhibit low response rates, requiring the identification of novel therapeutic targets. Materials and Methods We have previously generated an MCL cell line (UPN-1) from a patient with a blastoid variant of MCL presenting unique morphological and cytogenetics characteristics (M'kacher et al, Oncogene 2003). This cell line has been shown to harbor a TP53 mutation and a highly increased sensitivity to radiation despite the absence of functional p53. The molecular basis of this phenomenon has not been explored. In this work, we further characterized UPN-1 cell line using the Clarium S human microarray which has been compared to the gene expression profile of other existing MCL cell lines (GRANTA-519, JEKO-1, JVM-2, MAVEK-1, MINO, REC-1, SP-49, SP-53, Z-138). After mathematical correction, a supervised analysis was performed between triplicate samples of UPN-1 and a group constituted with all other MCL cell lines. We have then set up in vitro assays to determine the effect of a direct E2F1 inhibitor on the proliferative potential of UPN-1. Results The comparative transcriptome analyses revealed a list of 47 genes specifically upregulated in UPN-1. Unsupervised classification allowed to discriminate UPN-1 samples from other MCL cell lines based on the expression of these 47 genes. These data suggested a specific expression profile of UPN-1 as compared to other cell lines. Among the upregulated genes, E2F1 elongation factor was found to be highly upregulated in UPN-1 as compared to other MCL cell lines along with positive enrichment of E2F targets which are mainly implicated in cell cycle progression (Figure 1). Interestingly, UPN-1 has a low level of BCL-2 as compared to other MCL lines that could explain its radio sensitivity. However, other signaling pathways involved in the inhibition of apoptosis were found to be present in UPN-1 by geneset enrichment analysis. The expression of CDKN1A (p21), major cell cycle regulator and known as a marker of aggressive MCL, was found to be low in UPN-1. A repression of immune response pathway such as NFKB with low expression of NFKBIA was identified. Finally, the expression of PIK3CD which encodes for a therapeutic target in MCL (such as PI3KDelta inhibitor Idelalisib) was also significantly repressed in UPN-1 as compared to nine other MCL cell lines. To evaluate the effect of the direct inhibition of E2F1, we treated UPN-1 cells with a targeted E2F1 inhibitor 5‘-Deoxy-5‘-(methylthio)adenosine (MTA) which is a protein methylation inhibitor. MTT assays revealed a 50% reduction of proliferation at + 4 hours in comparison to the vehicle-treated conditions (P<0.0001).Annexin assays showed an increase in early apoptosis (36.6 %) at + 8 hours with subsequent rise in late apoptotic cells (64.5 %) observed after 24 hours of treatment. Interestingly, qRT-PCR analyses of MTA-treated cells exhibited a decrease in the expression of downstream factors associated with E2F1, such as RAD51, BRCA1, CDK2, CCNB2, RANBP1. Conclusions We report here for the first time the comparative transcriptome analysis of the unique aggressive blastoid MCL line UPN-1 as compared to other MCL lines described. This cell line exhibited a major upregulation of E2F1 expression and a down regulation of the cell cycle inhibitor CDKN1A(p21). The potential effects of the direct inhibition of E2F1 using the targeted inhibitor MTA demonstrated a reduction in cell proliferation and induction of apoptosis, suggesting the possibility of associating clinically acceptable E2F1 inhibition strategies to other current therapies.

The Impact of Induction Regimens on Clinical Outcomes in Double and Triple-Hit Lymphoma: A Meta-Analysis of Comparative Studies

Background: Double and triple hit lymphomas (DTHL) are aggressive high-grade lymphomas that harbor translocations of MYC and BCL2 and/or BCL6. They constitute 6-14% of all aggressive B-cell lymphoma and have been associated with poor clinical outcomes. Though there is no established standard therapy for DTHL, induction chemotherapy vacillates between R-CHOP-like regimens, R-EPOCH, or more dose-intense regimens (DI) such as R-hyperCVAD/MA and CODOX-M/IVAC with or without consolidation with stem cell transplant. Currently, there are no randomized trials establishing a standard induction regimen. Furthermore, several retrospective studies reported conflicting results regarding the comparative benefits of these various induction approaches. Therefore, we conducted this meta-analysis to evaluate the impact of induction chemotherapy regimens on the clinical outcomes of DTHL. Methods: A review of the medical literature was conducted using online databases. Inclusion criteria consisted of English language, diagnosis of DTHL, comparative studies of induction chemotherapy regimens, and studies that reported overall (OS) and progression-free (PFS) survival. Studies that reported the aggregate outcome of mixed samples of DTHL and other lymphomas were excluded. A meta-analysis using the fixed effects and random effects models was conducted. Results: Seven retrospective comparative studies with a total of 1433 patients were included. The median age was 62 years, and the median follow-up was 27.5 months. DI regimens were associated with better PFS than R-CHOP-like regimens (HR = 0.81, 95%CI 0.66-0.99, p = 0.039) but without improved OS. R-EPOCH, including R-DA-EPOCH, regimens were associated with better PFS than R-CHOP-like regimens (HR = 0.62, 95%CI 0.43-0.91, p = 0.013) but without improved OS. R-HyperCVAD/MA regimen was associated with better PFS compared to R-CHOP-like regimens (HR = 0.64, 95%CI 0.47-0.87, p = 0.005) but without improved OS. Conclusions: This is the first and largest meta-analysis to show that induction DI regimens, in general, and R-EPOCH and R-HyperCVAD/MA regimens, in particular, are associated with better PFS than R-CHOP-like regimens in patients with DTHL. However, this advantage did not translate into a survival benefit.

Exploration of Language As a Barrier to the Assessment and Management of CAR T-Cell Therapy Associated Toxicities

Introduction: Chimeric antigen receptor T-cell therapy (CAR T) is a novel therapy associated with a unique toxicity profile, namely cytokine release syndrome (CRS) occurring in (37-93%) of patients (pts) and immune effector cell associated neurotoxicity (ICANS) occurring in 23-67% of pts [Zahid, 2020]. Grading and management of these toxicities varies amongst institutions and patient populations. Furthermore, assessment of ICANS utilizes the Immune Effector Cell-Associated Encephalopathy (ICE) scoring system which includes 5-components that are dependent on a patient's English- speaking proficiency [Lee 2019]. We previously reported a higher-grade of neurotoxicity assessed in non-English speaking pts in a cohort of 127 pts at our institution [Melody, 2023]. We sought to confirm our previous findings by analyzing the impact of language spoken on the incidence, severity, and management including resource utilization for CAR T associated toxicities, in a larger multi-institutional cohort. Methods: We compiled retrospective data from 13 academic institutions for pts with aggressive B-cell lymphoma treated with CD-19 directed CAR T between 2015 through 2022. Baseline characteristics, lymphoma treatment, along with incidence, severity and management patterns of CRS and ICANS were compared between non-native English-speaking (NNES) and native-English speaking (ES) pts with Pearson Chi-squared test. OS was estimated via Kaplan-Meier method. Results: In a cohort of 582 pts treated with CAR T, 555 pts were ES and 27 were NNES pts; 17= Spanish, 3= Cantonese, 7= other (including Arabic, Burmese, Polish, Igbo, Japanese, Korean, & Mandarin). Demographic and clinical data for NNES and ES cohorts are included in Table 1. There was no difference in baseline disease characteristics between the two pt populations with the exception of younger pts and a higher proportion of women in the NNES group (p =0.02). Translator services were utilized for 20 (74%) of NNES pts at any point during CAR T-cell treatment. Two-thirds (66.7%) of NNES pts developed CRS (4=grade 0, 6= grade 1, 9= grade 2, 1= grade 3, 2 =grade 4, 5=Missing data) vs 55.5% of ES pts developed CRS (63=grade 0, 131= grade 1, 134= grade 2, 56= grade 3, 1 =grade 4, 1=grade 5, missing= 169), p < 0.001. For CRS management, there was no difference in the use of tocilizumab (48.1% vs 46.0%, p= 0.85) or escalation to ICU care (13.3% vs 10.1%, p= 0.66) for NNES vs ES groups, respectively. Thirty-seven percent of NNES pts developed ICANS (6=grade 0, 4= grade 1, 2= grade 2, 3= grade 3, 1=grade 4, 11=missing) compared with 39.8% of ES pts who developed ICANS (120=grade 0, 75= grade 1, 60= grade 2, 75= grade 3, 8= grade 4, 3= grade 5, missing= 241), p= 0.92. ICE scoring for ICANS assessment was recorded in 48% and 51% of NNES and ES pts, respectively. For management of ICANS, there was no difference in the use of steroids (51.9% vs 43.4%, p= 0.43), lamotrigine (61.5% vs 46.0%, p=0.39), or anakinra (10% vs 11.7%, p= 1.0) between NNES vs ES pts. There was no difference in escalation to ICU care for management of ICANS between groups (15.4% vs 19.1%, p=1.0). Neurology consults were obtained more frequently for NNES vs ES but this difference was not statistically significant (61.5% vs 40.5% respectively, p=0.16). Similarly, neuroimaging was obtained more frequently in NNES vs ES pts though not statistically significant (69.2% vs 53.4% respectively, p= 0.39). There was no difference between re-admission rates within 90 days post CAR T for NNES and ES pts (34.6% vs 26%, p = 0.36). With median follow-up of 35.3 mo (1.4-82.9), there was also no statistical difference in median overall survival of 17.8 mo in NNES pts compared to 28.9 mo in ES pts (p= 0.50; Figure 1). Conclusions: Despite our previous observations of increased severity of CRS and ICANS in NNES pts at our own institution, expansion to a larger multi-institutional cohort did not identify differences in occurrence, assessment, or management of toxicities between NNES and ES pts. Analyses were limited by small sample size of NNES patients and missing data for our patient cohort as a whole. This may be explained by decreased access to tertiary care for CAR T in NNES pts and highlights the lack of standardization in assessment and management of CRS/ICANS more globally. None-the-less, the assessment of language as a barrier to care warrants further exploration as does validation of current ICANS assessment tools in NNES pts.

Screening Cerebrospinal Fluid for Aggressive B-Cell Lymphoma: Significance of Clonal Populations Found with 8-Color Flow Cytometry

Background: Secondary central nervous system (CNS) lymphoma confers a poor prognosis, and prompt identification is critical for guiding management. Over the last decade, we have employed cerebrospinal fluid (CSF) analysis with 8-color flow cytometry (FCM) in screening patients deemed at risk of CNS relapse. However, there is little data to guide interpretation and management of positive results, and concurrent clinical and radiographic features of FCM positive (FCM+) patients, remain areas of uncertainty. Methods: We analyzed newly diagnosed (ND) and relapsed/refractory (R/R) diffuse large B cell lymphoma (DLBCL) and high grade B cell lymphoma (HGBCL) patients who underwent a screening lumbar puncture (LP) from 2011-2020. Clinical, imaging, and CSF findings (differential, cytology, FCM) were collected. Patients with prior CNS involvement or FCM showing CLL/low-grade B-NHL were excluded. “FCM-only” patients were defined as FCM+ but without any other evidence of CNS spread (negative cell count/cytology, MRI, and no symptoms), whereas others were deemed to have overt CNS disease. Results: There were 415 LPs among 361 patients (243 ND, 172 R/R). 21 (5%) patients were FCM+, 10 ND and 11 R/R patients (Table 1). Four had FCM-only involvement (2 ND, 2 R/R). Among these, the clonal population was 1.63% of WBC (range, 0.3-2.7%), and 3 had concurrent bone marrow (BM) or peripheral blood (PB) involvement. All 4 received intrathecal (IT) therapy. At median follow up of 23 months, 3 (75%) have died (2 from CNS disease progression, 1 unknown due to loss in follow up), and 1 remains alive in remission 44 months later following IT methotrexate (MTX) and CAR T-cell therapy. 17 had overt CNS disease (8 ND, 9 R/R). The clonal population was 9% (range, 0.2-98%). Eight (47%) had concurrent BM or PB involvement. Twelve (70%) received IV high dose MTX, and the remainder received only IT therapy. At median follow up of 42 months, 9 (53%) have relapsed (2 CNS only, 1 systemic, 6 both), and 9 have died. Median time to CNS relapse was 5 months. Conclusions: CSF 8 color FCM screening of DLBCL/HGBCL patients yields a low proportion of positive results, mostly in the setting of overt CNS disease. However, even FCM-only patients had poor outcomes (2/4 with CNS progression), suggesting that blood contamination does not explain CSF findings, and that these patients should be approached as secondary CNS involvement. Better pt selection for CSF screening is needed to reduce unnecessary LPs. Intensified or novel approaches for all FCM+ patients are needed.

Sickle cell allele HBB-rs334(T) is associated with decreased risk of childhood Burkitt lymphoma in East Africa.

Burkitt lymphoma (BL) is an aggressive B-cell lymphoma that significantly contributes to childhood cancer burden in sub-Saharan Africa. Plasmodium falciparum, which causes malaria, is geographically associated with BL, but the evidence remains insufficient for causal inference. Inference could be strengthened by demonstrating that mendelian genes known to protect against malaria-such as the sickle cell trait variant, HBB-rs334(T)-also protect against BL. We investigated this hypothesis among 800 BL cases and 3845 controls in four East African countries using genome-scan data to detect polymorphisms in 22 genes known to affect malaria risk. We fit generalized linear mixed models to estimate odds ratios (OR) and 95% confidence intervals (95% CI), controlling for age, sex, country, and ancestry. The ORs of the loci with BL and P. falciparum infection among controls were correlated (Spearman's ρ = 0.37, p = .039). HBB-rs334(T) was associated with lower P. falciparum infection risk among controls (OR = 0.752, 95% CI 0.628-0.9; p = .00189) and BL risk (OR = 0.687, 95% CI 0.533-0.885; p = .0037). ABO-rs8176703(T) was associated with decreased risk of BL (OR = 0.591, 95% CI 0.379-0.992; p = .00271), but not of P. falciparum infection. Our results increase support for the etiological correlation between P. falciparum and BL risk.

Clinical PD-1/PD-L1 Blockades in Combination Therapies for Lymphomas.

Immunotherapy with the programmed cell death protein 1 (PD-1)/PD-1 ligand (PD-L1) blockade has revolutionized the treatment of advanced solid cancers. However, these clinical benefits have been limited to cases of malignant lymphomas, showing promising results for only classic Hodgkin lymphoma (cHL) and primary mediastinal B-cell lymphoma (PMBCL). To bring clinical benefits to more patients with lymphoma, numerous combination therapies involving PD-1/PD-L1 blockade have been tested in clinical trials in both frontline and relapsed/refractory settings. This article reviews the current landscape of combination therapies with PD-1/PD-L1 blockade for lymphoma and discusses the potential therapeutic approaches. An interim analysis of a phase 3 study demonstrated increased progression-free survival with nivolumab combination therapy over the current frontline treatment in patients with advanced-stage cHL. The results of combination therapies for aggressive B-cell lymphomas, except for PMBCL, have been disappointing. Several clinical trials of combined PD-1/PD-L1 blockade and Bruton's tyrosine kinase inhibitors are exploring its efficacy in patients with chronic lymphocytic leukemia (CLL) with Richter transformation. Several T-cell lymphoma subtypes respond to PD-1/PD-L1 blockade monotherapy. Further clinical trials are underway to investigate appropriate combination regimens with PD-1/PD-L1 blockade, especially for cHL, CLL with Richter transformation, and T-cell lymphoma, in both frontline and relapsed/refractory settings.

RADT-44. LONG-TERM OUTCOMES WITH REDUCED-DOSE WHOLE BRAIN RADIOTHERAPY AND A STEREOTACTIC RADIOSURGERY BOOST FOR PRIMARY CNS LYMPHOMA

Abstract BACKGROUND Primary central nervous system lymphoma (PCNSL) is an aggressive diffuse large B-cell lymphoma. Treatment approaches are historically associated with neurotoxicity, particularly with high-dose whole-brain radiotherapy (WBRT). We hypothesized that reduced dose-WBRT (rd-WBRT) followed by a stereotactic radiosurgery (SRS) boost could provide durable disease control without significant adverse effects. METHODS We retrospectively reviewed PCNSL patients treated with rd-WBRT plus an SRS boost at Duke University between 2008 and 2021. Progression-free survival (PFS) and overall survival (OS) were estimated using competing risk and Kaplan Meier methods. RESULTS We identified 23 patients with pathologically confirmed PCNSL. Median age at diagnosis was 69 years (Q1Q3:52–74) and median KPS was 80 (Q1Q3:70–80). Median follow-up was 21 months. Median doses for rd-WBRT and SRS were 23.4Gy (Q1Q3:23.4–23.4) and 12Gy (Q1Q3:12–12.5), respectively. The cumulative incidence of intracranial progression at two years was 23% (95%CI:8-42). Six patients (26%) developed distant radiographic progression while two patients (9%) developed both distant and local progression. Ten patients (44%) were alive without progression at last follow-up. By Kaplan Meier estimate, the two-year overall survival was 69% (95%CI:46-84). There were no reported grade 3+ radiation-induced toxicities. CONCLUSIONS The combination of rd-WBRT with an SRS boost appears well-tolerated with durable intracranial control. This approach represents a treatment option for select patients, such as those with progressive or refractory disease. Further prospective studies are needed to validate these findings and determine whether this approach could be incorporated into consolidation strategies.

Frontline treatment of aggressive B-cell lymphoma

Aggressive B-cell non-Hodgkin lymphoma, which most often manifests as diffuse large B-cell lymphoma (DLBCL), is the most common non-Hodgkin lymphoma, accounting for up to 30% of diagnosed cases. It is responsible for considerable morbidity and mortality worldwide, with a global burden of approximately 150,000 new patients annually. Large B-cell lymphoma encompasses a group of lymphomas with significant clinical and biological heterogeneity. While there are approximately 18 variations of large B-cell lymphoma in the upcoming 5th edition of the World Health Organization classification of lymphoid neoplasms (WHO-HAEM5), for the purposes of this review the aggressive B-cell lymphomas will refer to the most common entity, diffuse large B-cell lymphoma, not otherwise specified (DLBCL), as well as diffuse large B-cell lymphoma/high-grade B-cell lymphoma with MYC and BCL2 rearrangements (DLBCL/HGBL-MYC/BCL2), and high-grade B-cell lymphoma, not otherwise specified (HGBL,NOS).

Trial-in-Progress: A Phase 1/2 Multi-Center Study of Onct-808, a ROR1-Specific CAR T, in Adult Patients with Relapsed/Refractory Aggressive B Cell Lymphoma

BACKGROUND: The therapeutic landscape for B-cell lymphomas (BCL) leverages several modalities, including chemotherapy, targeted agents, adoptive cell therapy, and immunotherapy. While these approaches have shown clinical benefit, challenges remain, such as variable response rates, treatment resistance, and toxicities. ROR1-specific CAR T-cell therapy represents a promising potential advancement in the treatment of aggressive BCL in patients (pts) who have failed previous CD19 CAR T therapy. ROR1-targeted CAR T therapy offers several advantages that could address these challenges. By directing CAR T cells to specifically recognize and eliminate ROR1-expressing tumor cells, it offers a highly targeted approach with the potential for enhanced efficacy. Moreover, ROR1 is often highly expressed on aggressive BCL, making it a suitable therapeutic target. This focused approach may help overcome the limitations associated with current treatments and improve response rates. After birth ROR1 is predominantly expressed on malignant cells; therefore, this selective expression pattern may reduce the risk of toxicities, including off-tumor target elimination and non-specific activation of immune cells. The development of ROR1-specific CAR T holds promise in enhancing the treatment outcomes for patients with aggressive BCL. With targeted action and potential to reduce toxicity, ROR1-specific CAR T cell therapy offers an innovative and novel strategy for improving patient outcomes in BCL. The ROR1 binding moiety for ONCT-808 is derived from zilovertamab. Zilovertamab vedotin showed preliminary evidence of efficacy and no evidence of on-target off-tumor toxicity in patients with advanced B cell malignancies (Wang 2022). METHODS: This is a Phase 1/2, single-arm, open-label, multi-center trial to evaluate the safety and efficacy of ONCT-808 in pts with aggressive BCL, including large B-cell lymphoma (LBCL) and mantle cell lymphoma (MCL) with no approved therapy available. The study comprises two distinct phases: Phase 1 for dose escalation followed by Phase 2 for dose expansion. In Phase 1, a standard 3+3 dose escalation design will be used with 3 provisional dose levels and expected sample size of up to 18 patients. Subjects will receive a conditioning regimen of intravenous (IV) cyclophosphamide and fludarabine, followed by ONCT-808 IV infusion. The dose of ONCT-808 will be sequentially escalated to determine the recommended Phase 2 dose (RP2D) for LBCL and MCL cohorts. Bridging therapy is permitted if clinically indicated. Phase 2 will enroll LBCL and MCL patients into separate dose expansion cohorts at the RP2D determined in Phase 1. ONCT-808 will be administered as a single IV infusion of autologous CAR T cells. The primary outcomes include assessing the incidence, severity, and relationship of Dose Limiting Toxicities (DLT), Treatment Emergent Adverse Events (TEAE), and RP2D selection of ONCT-808. Secondary outcomes include evaluating the Overall Response Rate (ORR), Complete Response (CR) rate, Duration of Response (DOR), pharmacokinetics of ONCT-808, expansion, persistence of ROR1 CAR-positive T cells, overall safety and tolerability. Key inclusion criteria include histologically confirmed aggressive B-cell NHL, measurable lesions per Lugano criteria (Cheson, 2014), and relapsed/refractory (R/R) disease without available therapy (must be previously treated with systemic therapy, progressed after or ineligible for autologous HSCT, and received prior approved anti-CD19 CAR-T at least 6 months prior to enrollment unless refused/ineligible). Key exclusion criteria include previous ROR1-targeted therapy, ongoing immunosuppression, and CNS involvement. The trial is currently active and patients have been treated in the phase 1 dose escalation. Clinical Trial Identifier: NCT05588440

The Presence of Bulky Disease and/or Very High LDH Defines a High-Risk Subset of IPI 1-2 for Eligibility in Clinical Trials of Newly Diagnosed Aggressive B-Cell Lymphoma

Background: The goal of clinical trial eligibility criteria is to identify a population of patients that have high risk disease or have unmet needs with standard of care therapy. Frontline trials of diffuse large B-cell lymphoma (DLBCL) include patients with International Prognostic Index (IPI) scores of 3-5 as a way to identify a high risk population. Trials typically include patients with IPI score=2, and sometimes IPI score=1, to expand the eligible patient population. However, broader patient populations must be balanced by the potential inclusion of low-risk patients with excellent outcomes to standard of care therapy, leading to potentially underpowered trials. IPI is a sum of dichotomous variables which makes implementation easy but can result in heterogeneity in outcomes within IPI scores. This heterogeneity may be caused by unequal prognostic information across IPI variables, loss of information within IPI variables due to the use of cutoffs, as well as information captured by variables that are not included in the IPI. In prior modeling of outcomes in DLBCL (Maurer et al, AJH 2016), we identified that: i) LDH has a strong prognostic ability beyond the upper limit of normal (ULN) and ii) bulky disease is an independent variable for prognosis. Here we evaluate if the presence of either of these two variables, easily captured at diagnosis within the current standard clinical work-up, can identify a high-risk subset of patients within the population of those with IPI scores of 1-2. Methods: Patients with newly diagnosed lymphoma were enrolled within 6 months of diagnosis in the LEO Cohort at 8 academic medical centers from 2015-2020 and prospectively followed. Inclusion criteria for this analysis was aggressive B-cell lymphoma typically included in frontline trials (e.g. DLBCL, high grade B-cell lymphoma, FL3B), IPI 1-5, frontline therapy with rituximab and anthracycline-based chemotherapy, stage II-IV disease and ages 18-80 years. Event-free survival (EFS) was defined as the time from diagnosis until progression, initiation of 2 nd line therapy, or death due to any cause; EFS was evaluated at 24 months (EFS24). Very high LDH was defined as LDH>1.3xULN based on prior modeling (Maurer et al, AJH 2016) and bulky disease was defined as maximum tumor diameter (MTD) of 7cm or greater. IPI 1 and 2 were first evaluated separately and then combined due to similar outcomes in patients with very high LDH and/or bulky disease. High risk IPI1-2 was defined as the presence of either bulky disease and/or very high LDH within an IPI score of 1-2. Confirmation was performed in a similar cohort of patients enrolled in the Iowa/Mayo SPORE Molecular Epidemiology Resource (MER) from 2002-2015; bulky disease was defined using a 10cm cutoff per availability in MER data collection forms. Results: 1560 patients from LEO were analyzed; median age was 64 years (IQR: 54-71), 42% were female and 83% had stage III/IV disease; subtype was DLBCL, NOS in 1335 (86%). IPI was 1-2 in 766 patients, 3 in 496 patients and 4-5 in 298 patients ( table). 391 (51%) with IPI1-2 had either bulky disease and/or very high LDH (high risk IPI1-2) and 375 had low-risk IPI1-2. EFS24 in high risk IPI1-2 (71.6%, 95% CI: 67.2-76.3) was significantly inferior to IPI1-2 without bulky disease or very high LDH (85.2, 95% CI: 81.7-88.9 logrank p=0.0035, figure) and similar to patients with IPI3 (70.7%, 95% CI: 66.8-74.9). Consistent results were observed in 1014 patients analyzed in the MER using a higher cutoff for bulky disease (10cm) due to data availability ( table). Patients with high risk IPI1-2 had significantly shorter diagnosis to treatment interval (DTI) in both the LEO (per-week OR=0.83, 95% CI: 0.77-0.88) and MER (per-week OR=0.77, 95% CI: 0.68-0.87) cohorts compared to low risk IPI1-2, both p<0.0001). In sensitivity analysis, LEO results were similar when performed in the subset of patients with DLBCL, NOS. Conclusion: The presence of either bulky disease and/or very high LDH at presentation identifies a high-risk subset of patients with IPI 1-2 that have similar outcomes to patients with IPI 3 disease. These simple criteria can be easily implemented within existing clinical trial diagnostic work-ups. Future trial designs in frontline aggressive B-cell lymphoma should include patients with IPI 3-5 and patients with IPI 1-2 with either bulky disease and/or very high LDH to better define a high-risk population of patients for clinical trial eligibility.

End-of-Treatment Response Assessment after Frontline Therapy for Aggressive B-Cell Lymphoma: Landmark Comparison of a Singular PET/CT Scan Versus Ultrasensitive Circulating Tumor DNA

Background : Lymphoma response criteria rely on PET/CT scans at end of therapy (EOT) to determine complete response (CR), which is necessary for cure. ~25% of patients achieve <CR by response criteria, but PET/CT scans have imperfect specificity and the positive predictive value of a single PET/CT scan at EOT is only ~50% (Kostakoglu 2021). To overcome this limitation, clinicians use additional tests including tissue biopsies or repeat PET/CT scans prior to salvage therapy to adjudicate positive results, but it remains unclear how often this occurs. Circulating tumor DNA (ctDNA) has improved tumor specificity that may reduce reliance on additional tests. We addressed these questions within a clinical trial delivering 1L therapy to pts with aggressive B-cell lymphoma. Methods : Pts were enrolled in a phase 2 study of DA-EPOCH-R or R-CHOP +/- acalabrutinib for treatment naïve DLBCL or high-grade B-cell lymphoma (HGBCL) [NCT04002947]. All pts were >18yrs old, stage II-IV, with adequate organ function. Pts completing induction therapy with available EOT PET/CT scans and EOT plasma samples were studied. PET/CT scans were interpreted by 2 nuclear medicine (NM) radiologists blinded to clinical outcomes using the 5-point Deauville Score (DS) with DS4/5 considered positive. Tissue biopsies and unplanned PET scans after the EOT PET/CT scan to determine remission status were recorded. Measurable residual disease (MRD) in plasma cfDNA was evaluated by Phased Variant Enrichment & Detection Sequencing (PhasED-Seq) at Foresight Diagnostics blinded to clinical outcomes. Tumor derived Phased Variants (PVs) were identified from baseline pretreatment plasma samples or baseline tumor tissue, with matched constitutional DNA from paired PBMCs used to censor germline variants and CHIP. PVs were used to assess EOT MRD. Results were reported as MRD positive when ctDNA levels exceeded an analytical detection threshold (~1:10 6 cfDNA molecules) corresponding to 98% specificity. The prognostic utility of MRD was compared to standardized PET/CT scan at EOT to freedom-from-progression (FFP) and progression-free survival (PFS). Results : 55 enrolled pts completing planned therapy had EOT PET/CT and MRD analyzed. 54 (98%) pts were successfully genotyped and comprised the study population. Median age was 61 (range 26-85), including 22 (41%) female, 44 (81%) with advanced stage, and 26 (48%) with IPI score ³3. Pathologic subtypes included 24 (44%) GCB, 21 (39%) non-GCB, 8 (15%) HGBL-DH, and 1 (2%) THRLBCL. 43 (80%) pts received DA-EPOCH-R and 11 (20%) pts received R-CHOP. Twenty-six (48%) pts received acalabrutinib with R-chemotherapy. After 26 months median follow-up, the 2-year FFP and PFS of the cohort was 89% and 84%. Fourteen (26%) pts had a positive EOT PET/CT scan and 40 (74%) were negative. The concordance rate between the 2 NM radiologists on positive scans was 100%. Only 2 of 14 patients with a positive EOT PET/CT had clinical progression requiring salvage therapy (14% PPV). Nine (64%) of these pts required additional tests to determine remission status including 5 repeat PET/CT scans and 4 tissue biopsies. The 2-year PFS for pts with a positive vs negative EOT PET/CT was 66% vs 90% (p=0.08, Fig.A). Twelve (22%) pts had detectable EOT MRD and 42 (78%) were undetectable. 7 pts with detectable EOT MRD had clinical progression requiring salvage therapy or have died. While no pt with undetectable EOT MRD progressed, 1 (2%) died in remission of sudden cardiac death. Of 14 pts with positive EOT PET/CT, 7 (50%) had undetectable ctDNA and none progressed, suggesting MRD testing could have potentially rendered additional tests unnecessary. Conversely, patients with positive PET/CTs who progressed invariably had detectable ctDNA at EOT, suggesting utility of MRD for adjudicating PET/CT results. The 2-yr PFS for pts with detectable vs undetectable EOT MRD was 33% vs 98% (p<0.0001, Fig.B). At EOT, the PFS hazard ratio for MRD was 35.7, as compared with 3.1 for PET/CT. Conclusions : Response evaluations relying on PET/CT scans often require additional tests and procedures to assess remission status in aggressive B-cell lymphomas. Initiation of salvage therapy without adjudication in patients not achieving CR by EOT PET/CT scans will result in overtreatment. Given the higher specificity and PPV of EOT MRD, we propose an integrated response evaluation strategy combining these methods to reduce unnecessary additional tests and overtreatment.

Comparing Clinical Characteristics and Outcomes of MYC and BCL6 Double Hit Lymphoma (DHL- BCL6) with Other Aggressive B-Cell Lymphomas: Understanding the Impact of New Who and International Consensus Classifications

Background: High Grade B cell Lymphoma (HGBL) with MYC and BCL2 and/or BCL6 rearrangements(R) was introduced as an entity in 2016 by the WHO revised 4 th edition. In 2022, both the WHO 5 th edition (beta version) and the International Consensus Classification (ICC) separated DHL- BCL2 (+/- BCL6-R)from DHL- BCL6 given differences in biology . However, while the ICC has maintainedDHL- BCL6 as a provisional entity, the WHO has removed the category, thus removing the requirement to FISH for BCL6-R in this setting. Clinical data on DHL- BCL6 is much more limited, as these cases represent only 10-20% of DHL and have been combined with BCL2-R cases in prior studies. Outcomes are variable in retrospective studies with no consistent data on prognosis or optimal therapeutic strategies. By retaining the category of DHL-BCL6 as a provisional entity, the ICC emphasized the need for further, multicenter, prospective studies evaluating the clinical and biological features of this disease. We herein report a comprehensive comparison of clinical characteristics and outcomes in patients with DHL- BCL6 compared to diffuse large B-cell lymphoma (DLBCL), not otherwise specified (NOS); DLBCL with MYC rearrangement only; DHL- BCL2; and HGBL, NOS in a large, multicenter, prospective cohort of patients from Lymphoma Epidemiology of Outcomes (LEO). Methods: Adult patients with newly diagnosed large B-cell or HGBL were enrolled within 6 months of diagnosis at one the 8 LEO cohort academic medical centers in the US between 2015 and 2020. Baseline characteristics were abstracted at the time of diagnosis per protocol. Based on FISH data patients were further sub mgrouped into DLBCL, NOS (without MYC rearrangement); MYC-R DLBCL, NOS; HGBL, NOS; DHL- BCL2 and DHL- BCL6. Event-free survival (EFS) was defined as the time from diagnosis until progression/relapse, retreatment, or death. Overall survival (OS) was defined as the time from diagnosis until death due to any cause. Results: A total of 1526 eligible patients were identified during this time period. All FISH data was available at the time of diagnosis and the choice of treatment was based on physician discretion. Median age at diagnosis was 63 years (IQR 53-72), with 148 (10%) patients in the AYA category, and 128 (8%) patients > 80 years. 58% (891) were male, 11% self identified as Hispanic or Latino, and 7% as Black/African American. The median diagnosis to treatment interval (DTI) was 20 days (IQR 12-32), and 33% had DTI < 14 days. The FISH-based subgroups were MYC-negative DLBCL, NOS (N=1146, 75%), MYC-R DLBCL,NOS 227 (N = 96, 6%), DHL- BCL2 (N=154, 10%), DHL- BCL6 (N=38, 3%), and HGBL, NOS (N=92, 6%). When available, COO by Hans algorithm was 92% GCB in DHL- BCL2 and 50% GCB in DHL- BCL6. Clinical characteristics can be found in the table. At a median follow-up of 49 months (IQR 36-67), 490 patients (32%) had an event and 356 patients (23%) died. EFS at 24 months (EFS24) was 75% (95% CI: 73-77). Patients with DHL- BCL6 were younger at diagnosis (median 60 years), had more extranodal site involvement (40%), more often stage III/IV disease (70%), and more often treated with a higher intensity regimen than R-CHOP (69%) compared to DLBCL,NOS and MYC-R DLBCL. DHL- BCL6 also had fewer patients that were males (47%), with DTI <=14 days (33%), NCCN IPI ≥ 4 (45%), elevated LDH (53%) than HGBL, NOS and DHL- BCL2. The 2-year EFS and OS rates were noted to be significantly better in the DHL- BCL6 (EFS 79%, 95% CI: 67-93; OS 92%, 95% CI: 84-100) as compared to DHL- BCL2 (EFS 58%, 95% CI: 50-66; OS 70%, 95% CI 63 - 78) and HGBL, NOS (EFS 74%, 95% CI: 65-84; OS 74%, 95% CI: 65-84 ), (Figure 1) but were comparable to that of DLBCL, NOS (EFS 78%, 95% CI: 76-81; OS 87%, 95% CI: 86-89). Conclusions: Our data support separating DHL- BCL6 from DHL -BCL2 as these patients form a unique subgroup with some clinical characteristics comparable to both DLBCL, NOS as well as HGBL, NOS and DHL- BCL2 subtypes. In this cohort, clinical outcomes are more comparable to DLBCL, NOS than DHL- BCL2 or HGBCL, NOS. More frequent use of intensive chemotherapy in DHL- BCL6 compared with DLBCL may account for this finding, although larger multicenter studies are needed. Our results support continued identification of DHL- BCL6 in the clinical setting to better understand optimal therapy and biology of this cohort.