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Introduction: Richter transformation is the development of an aggressive lymphoma, most commonly diffuse large B-cell lymphoma, in patients (pts) with chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL). Transformation into Hodgkin lymphoma (HT) is a rare event and outcomes in pts with this complication in the current CLL/SLL therapeutic era of small molecule inhibitors (SMI; e.g., Bruton tyrosine kinase inhibitors [BTKi] and BCL2 inhibitors [BCL2i]) are unknown. Methods: We conducted a retrospective study of pts from 12 academic centers. Pts with HT who had not previously received chemotherapy for CLL/SLL-directed treatment (tx) were included. Pt, disease, and tx characteristics were collected. HT was categorized into 3 groups: “Concurrent HT,” defined as HT and CLL/SLL diagnosed simultaneously (within 3 months); “HT without prior CLL/SLL tx,” defined as HT and CLL/SLL diagnosed >3 months apart with the CLL/SLL never treated; and “HT with prior non-chemotherapy tx for CLL/SLL” defined as having received non-chemotherapy CLL/SLL-directed tx prior to the diagnosis (dx) of HT. Overall survival (OS) was measured from HT dx and estimated using the Kaplan-Meier method. Cox regression model was used to identify prognostic factors associated with OS. Results: Within a total cohort of 402 pts with Richter transformation (all histologies) without prior chemotherapy, 41 pts with HT (10%) were identified: 12 with concurrent HT, 10 with HT without prior CLL/SLL tx, and 19 with HT with prior non-chemotherapy tx for CLL/SLL. The median age at CLL/SLL dx was 62 years (range 31-96 years) and 73% were male. At CLL/SLL dx, 67% (14/21 evaluated) had unmutated IGHV, and 24% (8/34 evaluated) had TP53 disruption (del(17p) and/or TP53 mutation). The median age at HT dx was 65 years (range 31-96 years) among all pts. At HT dx, there was no significant difference in highest SUV on PET (median 12.3, range 3-31.1), lactate dehydrogenase (LDH) level (median 242 U/L, range 112-859 U/L), or lymph node longest diameter (median 4.6 cm, range 1.6-25 cm) among the 3 subgroups. The median time from CLL/SLL dx to HT dx was 5.4 years (range 0.3-16.5 years) in pts with HT without prior CLL/SLL tx and 4.2 years (range 0.5-17.3 years) in pts with HT with prior non-chemotherapy tx for CLL/SLL. The median number of prior non-chemotherapy CLL/SLL-directed tx was 1 (range 1-6) and included BTKi only (n=17) and BTKi and BCL2i sequentially (n=2); no patient had received only prior BCL2i. Among the 19 pts with HT with prior non-chemotherapy tx for CLL/SLL, 18 pts were on active tx at time of dx (17 BTKi, 1 BCL2i). Initial HT management included: doxorubicin, bleomycin, vinblastine, dacarbazine (ABVD; n=16), brentuximab vedotin (BV)-AVD (n=10), radiation only (n=2), other systemic tx (n=11), and supportive cares / hospice (n=2). All but 1 of the 11 other systemic tx were various HL tx regimens. Across all pts with available data (n=32), the overall response rate to 1st line HT tx was 78% (69% complete response rate); 13% had progressive disease and 9% (n=3; all with concurrent HT) died within 6 months without formal response assessment. A total of 11 pts received at least 1 additional line of therapy for HT, which included BV (n=4), an immune checkpoint inhibitor (n=1), or both (n=6) at any point beyond 1st line HT tx. Median follow-up from HT dx was 32.8 months (range 2.4-253.8 months). The 36-month OS for the entire cohort was 75% (95% CI: 55-87%). The 36-month OS estimates by subgroups were: 62% (95% CI: 26-84%) in pts with concurrent HT, 100% in pts with HT without prior CLL/SLL tx (no events by 36 months), and 67% (95% CI: 33-87%) in pts with HT with prior non-chemotherapy tx for CLL/SLL. Exploratory univariable analysis identified TP53 disruption at CLL dx (HR 12.36; 95% CI: 2.55-59.84) and lymph node longest diameter (HR 1.32 per 1 cm increase; 95% CI: 1.12-1.55) and LDH 2-fold increase (HR 3.97; 95% CI 1.24-12.68) at HT dx as prognostic for worse OS. HT subgroup was not prognostic. Conclusions: This is the largest report of outcomes in pts with CLL/SLL who develop HT following SMI tx without any prior chemotherapy, representing a contemporary cohort. Prior CLL/SLL tx status was not associated with OS; however, cautious interpretation is required given the sample size. Our findings support the use of appropriate HL-directed treatment in the setting of HT; however, OS estimates remain worse than would be expected in an older adult de novo HL cohort (Cheng Blood Adv 2022).

Background: Management of cytokine release syndrome (CRS) with chimeric antigen receptor T cell therapy (CAR-T) has evolved in the last decade. First line treatment tocilizumab (toci) was initially given for grade 2 or higher CRS in clinical trials (Toci/CRS≥2). Earlier use of toci in grade 1 CRS was found to be safe without negative impact on clinical response in cohort 4 of ZUMA-1 study for axicabtagene ciloleucel (axi-cel) for B-cell non-Hodgkin lymphoma (NHL; Toci/CRS1). This practice was also adopted for other CAR-T therapies for other disease indications. Subsequently, FDA also updated the package insert for axi-cel in 2021 to include the use of prophylactic dexamethasone (ppx dex) to be given on days 0, 1, 2 of CAR-T infusion based on the results from cohort 6 of ZUMA-1. We examined CRS and ICANS (immune effector cell associated neurologic syndrome) outcome of patients who received FDA approved axi-cel in standard-of-care (SOC) practice with these evolving practices. Of note, adoption of ppx dex has been variable across CAR-T treatment centers in the US (Khurana et al, Blood 2022). At Mayo Clinic Rochester, patients considered high-risk for severe CRS/ICANS (those who received bridging therapy and had LDH above upper limit of normal and/or with secondary CNS involvement or other CNS pathologies) would be considered for ppx dex. Methods: Medical records of patients who received axi-cel in SOC between 2018 and 2023 at Mayo Clinic Rochester were reviewed. ASTCT guideline was used for CRS and ICANS grading. Categorical variables were compared using Chi-squared test and continuous variables were compared using Kruskal-Wallis test. Results: Among 187 pts receiving SOC axi-cel, the median age was 60 years and 121 (65%) were males, 152 (81%) had CRS, of which 73 (39%) were grade ≥2; 97 (52%) had ICANS, of which 65 (35%) were grade ≥2. Of the 152 CRS pts, 54/152 (36%) pts never received toci or ppx/dex. Of the pts who received Toci, 35/152 (23%) received Toci when CRS is at least grade 2 (Toci/CRS≥2), 49/152 (32%) received Toci/CRS1 without ppx dex (Toci/CRS1), and 14 (9%) received ppx dex with Toci given in CRS1 when pts developed CRS (PPX DEX). Baseline demographics were comparable except age (Toci/CRS≥2: 58y; Toci/ CRS1: 63y; ppx dex: 50y; p=0.001) and pre-LD CRP (Toci/CRS≥2: 34mg/L; Toci/ CRS1: 6mg/L; ppx dex: 16mg/L; p=0.002). Pre-LD LDH and ferritin were also comparable. PPX DEX or Toci/CRS1 had significantly lower rate of maximum grade CRS≥2 (PPX DEX: 4 (29%); Toci/ CRS1: 20 (41%); 35 (100%); p<0.001) and duration of CRS (PPX DEX: 2.5d; Toci/ CRS1: 3d; Toci/CRS≥2: 5d; p<0.001). Time to onset of CRS was not statistically different between the 3 groups. Not surprisingly, Toci/CRS1 group had higher overall rate of toci use, compared to . Interestingly, use rate of ≥2 doses of Toci or siltuximab was significantly higher in Toci/CRS1 or PPX DEX (PPX DEX: 8 (57%); Toci/ CRS1: 26 (53%); 9 (26%); p=0.02). Pt who received PPX DEX or Toci/CRS1 had a significantly lower rate of ICANS (PPX DEX: 6 (43%); Toci/ CRS1: 33 (67%); 32 (91%); p=0.001) and rate of max grade ICANS ≥2 (PPX DEX: 3 (21%); Toci/ CRS1: 23 (47%); 27 (77%); p<0.001). The time to onset and duration of ICANS was not different among the 3 groups. Conclusion: Our real-world study shows that earlier use of Toci in grade 1, compared to its first use in grade 2, can result in lower overall incidence of more severe CRS, duration of CRS, incidence of ICANS and more severe ICANS. While we selected patients at higher risk for having more severe CRS in our PPX DEX cohort, experience to date suggests that these patients, compared to toci/CRS>=2 cohort, could also have reduced severity of CRS and ICANS with this updated management.

Background: The Optimized Hemophagocytic Lymphohistiocytosis (HLH) Inflammatory (OHI, Zoref-Lorenz et al, Blood, 2022) index, defined by the combined elevation in serum soluble CD25 (sCD25) and ferritin, has emerged as a promising prognostic tool for patients with newly diagnosed hematologic malignancies, demonstrating superior performance in predicting 500-day mortality compared to HLH-2004 criteria. However, previous studies were retrospective, with a substantial proportion (65%) of patients suspected clinically to have HLH. We evaluated the performance of the OHI index in an unselected, prospective cohort of newly diagnosed diffuse large B-cell lymphoma (DLBCL) patients. Methods: We analyzed the predictive utility of the OHI index in 331 newly diagnosed DLBCL patients enrolled from 2002-2015 in the prospective Iowa/Mayo Molecular Epidemiology Resource cohort. Ferritin and sCD25 levels were quantified in pre-treatment serum samples using R&D ELISA kits. OHI values were also optimized based on 500-day mortality in the cohort using receiver operating curve analysis with internal validation. Patients were classified as OHI+ using the original and newly optimized thresholds for sCD25 and ferritin. The primary endpoint was 500-day survival, and the secondary endpoints were event-free survival (EFS) at 24 months (EFS24), EFS, and overall survival (OS). The predictive capability of the OHI index was evaluated using logistic regression to determine odds ratios (OR) and 95% confidence intervals (CI) for 500-day mortality and EFS24, as well as Cox regression to calculate hazard ratios (HR) and 95% CIs for EFS and OS. Results: The median age at diagnosis of the 331 patients was 63.5 years (interquartile range, 54.5-74), and 168 (51%) were male. Using the original thresholds (sCD25 3,900 U/mL and ferritin 1,000 ng/mL), 4.2% of patients were OHI+, with a more than 5-fold higher 500-day mortality risk compared to OHI- patients (OR=5.6; CI 1.6-17, p<0.001). After optimizing thresholds for sCD25 (2,400 U/mL) and ferritin (250 ng/mL) to predict 500-day mortality, 23.6% were OHI+ and the OHI+ group had a 9-fold higher 500-day mortality risk (OR=9.2; CI 4.0-24, p<0.001), with 31% mortality in the OHI+ vs 5% in the OHI- group. OHI+ patients exhibited more B-symptoms (35% vs 20%, p=0.027), elevated LDH levels (76% vs 34%, p<0.001), poorer performance status (Eastern Cooperative Oncology Group 2+: 38% vs 12%, p<0.001), and more advanced stage disease (Stage IV: 57% vs 38%, p<0.001), although the frequency of a high International Prognostic Index (IPI) was not statistically different between the groups (IPI 3-5: 44% vs 36%, p=0.28). After adjusting for age and IPI, OHI+ remained a strong predictor of 500-day mortality (OR=5.0; CI 1.9-13, p=0.001). Further adjustment for the cell of origin did not impact the results. The association of OHI+ status with 500-day mortality was similar in IPI 0-2 (OR=5.8; CI 1.2-29, p=0.033) and 3-5 (OR=6.8; CI 0.6-73, p=0.11). OHI+ patients were also more likely to not achieve EFS24 (45% vs 13%), with a 3-fold greater risk after adjusting for age and IPI (OR=3.2; CI 1.5-6.5, p=0.0018). The OHI index also retained its predictive ability over longer-term follow-up (median 9.8 years for living patients) for both OS (HR=2.0; CI 1.0-4.0, p=0.040) and EFS (HR=2.2; CI 1.1-4.3, p=0.030) after adjusting for age and IPI. Cytokine profiling using multiplex ELISA identified elevated inflammatory markers in OHI+ patients, underscoring the role of systemic inflammation in prognosis. The distribution of cytokines was significantly different between the groups, with consistently higher means in the OHI+ vs OHI- group, including IL1a (1,628 vs 759 pg/ml, p=0.008), CCL2 (1,020 vs 724 pg/ml, p=0.028), CXCL10 (165 vs 53 pg/ml, p<0.0001), and CXCL9 (380 vs 150 pg/ml, p<0.0001). Conclusions: While the original OHI index for prediction of 500-day mortality was validated in this unselected cohort of newly diagnosed DLBCL patients, optimization of the OHI thresholds identified a larger OHI+ group (24%), enhanced the identification of hyperinflammation, improved predictive ability for early (500-day) mortality, and predicted EFS24 status and long-term OS. This underscores the clinical relevance of the OHI index, supports the need to evaluate disease-specific thresholds, and suggests its potential for use in routine management and as enrollment criteria in clinical trials for novel therapies.

Introduction: Mantle cell lymphoma (MCL) is an uncommon B-cell non-Hodgkin lymphoma (NHL) Prognosis is highly variable due to underlying biological and molecular heterogeneity. The first-line (1L) treatment paradigm for MCL continues to evolve with increasing use of bruton tyrosine kinase inhibitors (BTKi) and decreasing use of autologous stem cell transplant (ASCT). TP53 alterations are associated with inferior outcomes in MCL. The aim of this retrospective study is to determine treatment strategies and clinical outcomes in MCL patients based on TP53 gene mutation status. Methods: Retrospective data were collected from 19 institutions in the United States from 1/1993 to 1/2024. We examined treatment patterns and outcomes among MCL patients >18 years of age with known TP53 mutation status by sequencing. Patients who did not receive treatment were excluded. The analysis was stratified based on presence of TP53 mutations. Systemic therapies were categorized as chemo-immunotherapy (CIT), non-chemotherapy (including monoclonal antibodies, lenalidomide, venetoclax, and novel agents on clinical trial), and regimens containing BTKi. The primary outcome was overall survival (OS) and secondary outcomes were progression free survival (PFS) and time to next treatment (TTNT). OS and PFS were estimated with the Kaplan-Meier method and log-rank tests were used to compare groups. Results: 645 patients were included in the study, with 468 men (72.6%) and median age was 64 years (range 30-89). 230/645 patients (35.7%) had a TP53 mutation, of which 182 (79%) were identified prior to 1L. While the male/female distribution was the same between the mutated and unmutated groups, median age at diagnosis and MIPI risk score was higher in the TP53 mutated group (age 65.9 vs 63.1 yrs, p= 0.015; MIPI 6.4 vs 6.1, p<0.001). TP53 unmutated patients had a median of 1 line of therapy vs. 2 for the mutated group (p<0.001, range 1-8). Blastoid histology and higher ki67 were also associated with the TP53 mutated group (p=0.045, 0.01 respectively) The median OS was 14.2 years for TP53 unmutated and 8.3 years for TP53 mutated patients (p<0.0001). PFS in 1L was 0.95 years in TP53 mutated compared to 2.02 years in TP53 unmutated group (p<0.0001). Selection of 1L therapeutic strategy was not associated with presence of TP53 mutation (Χ2 p= 0.21) although more patients in the TP53 unmutated group underwent ASCT (119/415 vs 38/230; Χ2 p=0.0006) TP53 mutation was associated with inferior survival compared to TP53 unmutated patients for CIT in 1L but the difference did not reach statistical significance when non-chemotherapy regimens and regimens containing BTKi were used. For CIT in 1L, 5 year OS was 78% [71-84%] for unmutated compared to 58% [48-67%] for the mutated group (p=0.0001 ). For non-chemotherapy regimens, 5 year OS for unmutated patients was 73% [52- 86%] compared to 52% [25-73%] for the mutated group (p=0.09). For regimens containing BTKi, 5 year OS for unmutated was 93% [81-97%] compared to 57% [28-78%] for mutated (p=0.07). Within the TP53 mutated group, there were no differences in any clinical outcomes between those receiving CIT, non-chemotherapy, or BTKi in 1L. While median OS appeared numerically longer in the BTKi group (14.4 yrs vs 8.8 yrs for CIT and 6.8 yrs for non-chemotherapy), the difference did not reach statistical significance (p=0.58). In contrast,TP53 unmutated patients who received CIT in 1L had better TTNT (p=0.0039) compared to those in non-chemotherapy and BTKi groups. There was no improvement in PFS (p=0.79) or OS (p=0.47). Conclusions To our knowledge this is the largest retrospective real world dataset of MCL treatment outcomes stratified by TP53 mutation. As in prior studies, TP53 mutation portends a worse prognosis in MCL compared to TP53 unmutated patients, but outcomes are better than historically reported. CIT in 1L was not associated with improved OS in either group. Irrespective of TP53 mutation status, incorporation of BTKi in first line was not associated with improved clinical outcomes. The gap in OS between TP53 mutated and unmutated MCL may be narrowing as treatment paradigms shift away from intensive induction chemotherapy and ASCT, and due to an increasing number of effective therapies for relapsed patients. Clinical trials of novel agents are needed to further improve the OS of TP53 mutated MCL patients.

Introduction: NPM1 mutations, seen in up to 30% of adults with acute myeloid leukemia (AML), often co-occur with FLT3 internal tandem duplication (FLT3-ITD). Measurable residual disease (MRD) testing before allogeneic hematopoietic cell transplant (alloHCT) for persistence of mutated NPM1 and/or FLT3-ITD can identify patients with AML in complete remission (CR) at highest risk of relapse and death. Quantitative RT-PCR assays are currently recommended for NPM1 MRD testing, while FLT3-ITD MRD testing is DNA-based using next generation sequencing (NGS). DNA-based NGS assays for mutated NPM1 MRD testing may have several advantages but require validation. We performed NPM1 MRD detection in blood collected from patients with AML during first CR (CR1) prior to alloHCT on a subset of patients from the Pre-MEASURE study (PMID: 36881031) using a highly-sensitive, commercially available DNA-based NPM1 NGS MRD assay. Methods: Of the 531 patients aged 18 or older from the Pre-MEASURE study who received an alloHCT for NPM1mutated AML during CR1 at a CIBMTR reporting site in the USA between the years of 2013-2019, a subset of 190 were randomly selected to be included in this analysis. A commercially available research testing kit (IVS, Invivoscribe, San Diego, CA), which can detect DNA-based NPM1 MRD, was used to establish a workflow following clinical testing standards and validated to detect NPM1 insertion variants down to a variant allele fraction (VAF) of at least 0.005%. Results were compared to those previously reported using an anchored multiplex PCR-based (AMP) targeted NGS assay (detection limit 0.01%) and FLT3-ITD MRD results, where applicable. Overall survival (OS) and cumulative incidence of relapse were estimated with the day of transplant as time 0 using Kaplan-Meier estimation (log-rank tests), Fine and Gray model, and Cox proportional hazards models. Results: NPM1 NGS MRD testing was successful for 186 (98%) patients, of which 48 (26%) relapsed (median: 4.0 months; range: 0.7-52.5) and 64 (34%) died (median: 9.7 months; range: 0.4-58.9) post-alloHCT. The IVS assay detected NPM1 insertion variants in 71 patients with a median VAF of 0.0026% (range:0.0002-2.1%). Using a VAF threshold of ≥0.01% for MRD positivity, the IVS test showed that 24 patients tested positive for NPM1 MRD pre-alloHCT, which was associated with significantly increased rates of relapse (52% vs 20% at 3yrs; HR=4.3; P<0.001) and decreased OS (34% vs 71% at 3yrs; HR=3.6; P<0.001) compared to testing negative, in close alignment with those previously reported using the AMP assay. After removing the VAF threshold, an additional 47 patients were classified as NPM1 MRD positive, which remained associated with increased rates of relapse (40% vs 15% at 3yrs; HR=3.4; P<0.001) and decreased OS (50% vs 75% at 3yrs; HR=2.9; P<0.001). In multivariable analysis, residual NPM1 MRD burden prior to alloHCT was associated with risk of relapse and death in a dose-dependent manner. Patients were further subdivided based on their reported FLT3-ITD mutational status at baseline. Increased risk of relapse was seen for NPM1 MRD positive patients regardless of baseline FLT3-ITD. 123 (66%) patients were co-mutated for FLT3-ITD at baseline and previously tested for FLT3-ITD MRD using the IVS assay (PMID: 38696205). Defining MRD based on the presence of NPM1 vs NPM1 and/or FLT3-ITD revealed equivalent levels of relapse (45% vs 44%) and OS (45% vs 46%) at 3 years, with NPM1 MRD evaluation identifying 5 additional relapses. These results were confirmed in the full Pre-MEASURE cohort (n=317) using the AMP assay. NPM1 MRD positive patients receiving nonmyeloablative conditioning or reduced-intensity conditioning (RIC) without melphalan (mel) had increased risk of relapse or death compared to patients receiving myeloablative conditioning or RIC with mel, regardless of FLT3-ITD co-mutational status (3yrs: relapse 87% vs 55%, P=0.006; OS 15% vs 42%, P=0.013). Conclusions: In patients with NPM1 mutated AML from the Pre-MEASURE study, we show that detection of residual NPM1 variants in pre-transplant blood during CR1 using a highly sensitive DNA-based assay is associated in a dose-dependent manner with a significantly increased risk of relapse and death after allo-HCT, which can be mitigated in part by conditioning regimen. In patients co-mutated for both FLT3-ITD and NPM1 at diagnosis, NPM1 should be prioritized as a target for NGS-MRD if only one test is available.

Background: Chimeric antigen receptor T-cell (CAR-T) therapy has shown substantial promise in treatment of hematological malignancies, including non-Hodgkin Lymphoma (NHL). A subset of patients develop prolonged cytopenia, comprising quality of life, increasing healthcare utilization, and imparting considerable morbidity and mortality. Therapy-related myeloid neoplasms (t-MN), typically seen in patients who receive DNA-damaging agents such as radiotherapy and alkylators, have also been observed in CAR-T recipients. CAR-Hematotox score predicts the development of hematotoxicity in CAR-T recipients using laboratory parameters obtained at lymphodepleting (LD) chemotherapy, a timepoint when the patient has already gone through leukapheresis thus committed to the CAR-T process. Therefore, it is critical to identify patients at the highest risk of prolonged cytopenia and/or t-MN prior to apheresis, making it possible for a better triage of those who will proceed with CAR-T and those who might benefit from other strategies. Methods: A retrospective analysis was conducted in NHL patients who received commercial CAR-T products between January 2018 and March 2024 at Mayo Clinic Rochester, Arizona and Florida. Clinical and laboratory data including age, hemoglobin (Hb), absolute neutrophil count (ANC), platelet (PLT), ferritin, and LDH, obtained at the initial CAR-T evaluation, typically within 1 week of leukapheresis, were used for analysis. Prior lines of therapies including autologous stem cell transplant (ASCT) were collected. Prolonged cytopenias were defined as Hb < 8 g/dL, ANC < 0.5 x 109/L, and/or PLT < 50 x 109/L at 3 months after CAR-T. t-MN was diagnosed per WHO 2016. For prolonged cytopenia, the optimal cutoff points for continuous variables were determined by maximizing the sum of sensitivity and specificity. Logistic regression was then used to determine the factors associated with cytopenia at 3 months post-CAR-T. For t-MN, maximally selected log-rank statistics was used to determine the optimal cutoffs. We used competing risk analysis to determine the factors associated with development of t-MN. Death without t-MN was considered a competing risk. For both analyses, the factors with P < 0.1 in univariate analysis (UVA) were included in multivariate analysis (MVA). Results: Among the 387 NHL patients, with a median follow-up of 11 months (95% CI 8.7 - 12.2 months), 56 (14.4%) developed (41, 10.5% with 1 cytopenia; 14, 3.6% with 2 and 1, 0.2% with cytopenia in all 3 lineages), 20 (5.2%) developed and 315 (81.2%) did not have either. Factors associated with prolonged cytopenia: were age >, PLT ≤ 150, ferritin ≥ 600, and LDH ≥ 250. Univariate analysis identified baseline Hb, ANC, PLT and ferritin to be significantly associated with prolonged cytopenia. MVA identified Hb ≤ 11 (HR = 1.98; 95% CI 1.03-3.85, P = 0.042) and PLT ≤ (HR = 2.56; 95% CI 1.39-4.78; P = 0.003) to be associated with the development of prolonged cytopenia. Factors associated with t-MN:were age > 65 years, Hb ≤ 9 g/dl, ANC < 3.8, PLT ≤ 80, Univariate analysis identified age, Hb, ANC, PLT, ferritin, and ≥ 3 prior lines of treatment to be significantly associated with t-MN. On MVA, age ≥ 65 (HR = 3.91; 95% CI 1.52-10.03; P = 0.004), Hb ≤ 9 (HR = 3.49; 95% CI 1.38-8.85; P = 0.008), ferritin ≥ 300 (HR = 3.06 ; 95% CI 1.08-8.67; P = 0.035) and ≥ 3 prior lines of therapy (HR = 3.25; 95% CI 1.33-7.94 ; P = 0.010) were associated with t-MN development. Association of prolonged cytopenia with t-MN development: Prolonged cytopenia was noted in 45% of patients who developed t-MN and 15% of those who did not (P = 0.002). Cumulative incidence of t-MN at 1 year was 3.3% and the presence of prolonged cytopenia was associated with a higher 1of t-MN (HR 8.93, 95% CI 2.15 - 37.1, P = 0.003). Conclusions: Readily accessible clinical and lab data such as blood count and inflammatory markers at the time of CAR-T evaluation were associated with the development of prolonged cytopenias. Similarly, advanced age, anemia, high ferritin levels and history of ≥3 lines of therapy were associated with the development of t-MN. These findings, when validated in larger dataset, can be used for patient counseling and therapy selection by identifying patients at high-risk of developing hematotoxicity and/or t-MN development.

Background Follicular lymphoma (FL) is a generally indolent disease where a watch and wait strategy is standard in asymptomatic patients (pts) with a low tumor-burden. Harnessing antitumor immunity through an anti-tumor immunization strategy at this stage may delay or avoid the subsequent need for more toxic and complex therapies. EO2463 is a therapeutic vaccine designed from non-self protein sequences, derived from gut bacteria, including 4 HLA-A2 synthetically produced 9-mer CD8 cytotoxic T cell epitopes, exhibiting molecular mimicry with specific epitopes on the B cell markers CD20, CD22, CD37, and CD268 (BAFF-receptor). Additionally, EO2463 contains a CD4 helper epitope UCP2 derived from hTERT. The compound expands pre-existing memory CD8 T cells recognizing the non-self protein sequences from gut bacteria which can then cross-react with the selected B cell antigens on tumor cells. EO2463 is being used to drive anti-tumor immunity against B cell malignancies, and has demonstrated long-lasting, specific CD8-memory T cell responses and clinical activity in relapsed/refractory FL and marginal zone lymphoma (MZL) [J Clinical Oncol 2024, 42 (S16), 7058]. Furthermore, CD8 T cells expanded from samples of patients treated with EO2463 can kill HLA-A2 expressing lymphoblastoid cell lines presenting the B cell targets [Hematological Oncol 2023, 41 (S2), 581-582]. Methods The current report describes Cohort 2 of trial EONHL1-20/SIDNEY (NCT04669171) and includes pts with newly diagnosed, previously untreated FL, grade 1-3A, HLA-A2, and not in need of treatment. Pts receive EO2463 (300μg/peptide) SC with adjuvant Montanide ISA 51 VG, q2 weeks (w) x 4, then q4w, for a total of 12 doses (39w; PET-CTs at w6, w19, and w42). Planned accrual for this cohort is 25 pts. Immune responses were assayed on thawed pt peripheral blood mononuclear cells by flow cytometry and EO2463 peptide specific tetramers or by IFN-γ ELISPOT (assaying responses against 9-mer peptides from CD20, CD22, CD37, and CD268; and from peptides of EO2463) without any proceeding in vitro stimulation (ex vivo). Results As of June 2024, 15 pts had started study treatment. Median age was 62 (range 55-66) year, 7 male and 6 female, 2 pts Ann Arbor stage I/II, 5 stage III, and 8 stage IV. Ten of 15 pts were still on treatment; median treatment duration was 18.4 weeks (range 5-39 w) for all pts. Among 13 evaluable pts, best responses by PET-CT using Lugano criteria were 1 pt CR, 5 pts PR (46% objective responses (OR)), 3 pts SD, and 4 pts PD. Of those with PD per Lugano, 2 had isolated increases in FDG-uptake without increase in lesion size/number at w6 and both remain on treatment (per protocol based on LYRIC criteria). OR was first noted w6 in 3 pts and w19 in 3 pts; duration of response is not evaluable at this time due to short follow-up. The pt with CR had isolated increases in FDG-uptake at w6, PR at w19, and CR at w35. Anti-EO2463 immune responses were observed in 4 of 5 tested pts at the 1st testing timepoint (w5) and onwards (currently longest tested up until w31). In an exploratory analysis, the percentage of EO2463 peptide specific CD8 T cells measured by tetramers seemed linked to clinical response (OR 3 pts vs non-OR 2 pts; 2-sided T-test, p=0.02; range of percentages in pts with OR 0.85%-1.39% of all CD8 T cells in peripheral blood, range in pts with non-OR 0.17%-0.27%). Functionality and cross-reactivity of responses were shown by IFN-γ ELISPOT using 9-mer peptides corresponding to the B cell targets in 4 tested pts. Expanded antigen-specific CD8 T cells displayed a memory phenotype; effector/memory (TEM), and terminally differentiated effector memory CD8 T cells (TEMRA). The most common related AEs were grade 1 (7 pts) and grade 2 (5 pts) local administration site reactions (mainly erythema, pruritus, and induration). Other related AEs in > 1 pt were grade 1 headache (2 pts) and grade 1-3 fatigue/asthenia (3 pts). Asthenia lasting 2 days was the only related grade 3 adverse event (AE). Conclusions EO2463 monotherapy is associated with a very manageable safety profile and appears to demonstrate meaningful single-agent efficacy in FL. Consistent with the preclinical hypothesis, expansion of specific CD8 memory T cells may be associated with response. Results will be expanded at the meeting. Study EONHL1-20/SIDNEY also includes cohorts, not covered in this abstract, exploring EO2463 plus rituximab for 1st line FL/MZL, and EO2463 plus lenalidomide/rituximab in relapsed FL/MZL.

Background: Whereas major improvements have been made in the treatment of advanced HL outcomes of patients > 60 yrs are generally suboptimal compared with younger patients, and generally with more toxicity. To address this issue we conducted the first phase II study of BV-nivo in older pts with HL (ACCRU RU0515051, NCT02758717), with initial results reported at a median of 20.2 mo of follow-up. (Cheson et al, Lancet Haem, 11:e808, 2020). Herein we present the 5-year follow-up for this study. Methods: Eligible pts were either >60 yrs or considered unsuitable for standard chemotherapy because of cardiac, pulmonary or renal dysfunction. Pts received BV at 1∙8 mg/kg (dose cap at 180 mg) and nivo at 3 mg/kg both intravenously every 21 days for 8 cycles.The primary endpoint was overall response rate (ORR). Results: Follow-up data were available for 39 of the original 46 pts. At a median follow-up of 58.5 months (0.45-65.4 mo), the median duration of response was 17.2 mo (11.6-45.2). 58.7% of the patients had progressed with the median progression-free survival of 18.3 mo (12.8-46.3 mo); thus 41.3% had still not experienced a progression event. Median overall survival was not yet reached with 84.8% of patients still alive. Conclusions: BV-nivo is an effective regimen for patients >60 yr, curing approximately 40% of pts. For those not cured by initial therapy, outcome with subsequent treatment is excellent, suggesting check point inhibitor sensitization, or other factors. Optimization of dose and schedule, and incorporation of other novel agents will result in a successful chemo-free approach for older patients with HL, especially those unable to receive an anthracycline.

Background: Anaplastic large cell lymphomas represent a group of T-cell lymphomas that have long been broadly classified by the presence or absence of ALK fusion proteins (ALK+ or ALK−, respectively). However, recent discovery of extensive additional molecular heterogeneity has both promoted refinement of disease classification and uncovered new opportunities for biomarker-guided targeted therapy. In addition to recognition of a new genetic subtype, ALK− ALCL with DUSP22 rearrangement (R), a new molecular classification has been proposed based on the recent discovery of 2 overarching molecular types of ALCL, defined by the presence (Type I) or absence (Type II) of a gene expression signature highly enriched for JAK-STAT3 activation. BCL2 is a mitochondrial membrane protein that functions to inhibit the actions of pro-apoptotic proteins such as BAX and BAK and can be targeted clinically by BCL2 small molecule inhibitors. BCL2 has been reported to be expressed more frequently in ALK− ALCL than in ALK+ ALCL, but its expression in the context of current molecular findings is unknown. Methods: ALCLs were centrally reviewed and classified by current WHO/ICC criteria. BCL2 was performed using IHC and scored as positive if ≥30% of tumor cells showed staining. DUSP22-R was assessed by fluorescence in situ hybridization (FISH) using a breakapart probe set and a dual-color, dual-fusion (D) probe set for the most common DUSP22 translocation, t(6;7)(p25.3;q32.3). pSTAT3Y705 IHC, which is >90% accurate for Type I/II assignment based on gene expression, was performed and scored based on a previously validated cut-off of ≥30%. Results: We evaluated 217 ALCLs (148M/69F; age: mean, 57 y; range, 5-93 y), including 55 systemic ALK+ ALCLs, 127 systemic ALK− ALCLs, and 35 primary cutaneous (pc) ALCLs. Overall, 86/217 cases were positive for BCL2 (40%). BCL2 was positive in 67/127 ALK− ALCLs (53%) and 15/35 pcALCLs (43%; P=NS), but in only 4/51 ALK+ (7%; P<0.0001). DUSP22-R was present in 90 cases (63 ALK− ALCL and 27 pcALCL). BCL2 was positive in 57/90 cases with DUSP22-R (63%) compared to 29/127 without DUSP22-R (23%; P<0.0001). Among 85 cases with DUSP22-R and informative D-FISH testing, BCL2 was positive in 24/36 cases with t(6;7)(p25.3;q32.3) (67%) and 31/49 cases without t(6;7)(p25.3;q32.3) (63%; P=NS). Among 213 cases with informative pSTAT3Y705 staining, BCL2 was positive in 13/88 pSTAT3+ cases (Type I, 15%) and 70/125 pSTAT3− cases (Type II, 56%; P<0.0001). Conclusions: We identified a complex pattern of BCL2 expression across ALCLs that strongly correlates with a recently introduced molecular classification based on gene expression profiling. While our findings are in keeping with the previously reported low expression in ALK+ ALCL, we found that the higher expression in both systemic ALK− ALCL and pcALCL is particularly associated with DUSP22-R and the absence of pSTAT3Y705 expression (Type II ALCLs). The discovery of 2 overarching types of ALCL associated with the presence or absence JAK-STAT3 pathway activation represents a new conceptual framework for classifying ALCL and understanding its therapeutic vulnerabilities. Of note, previous data demonstrated that Type II ALCLs are enriched for epigenetic alterations and particularly overexpress the histone methyltransferase EZH2. Correlation between BCL2 expression and EZH2 expression also is observed in other lymphomas such as diffuse large B-cell lymphoma, where dual targeting with EZH2 and BCL2 inhibitors has been proposed. Thus, our findings provide further rationale for stratifying Type I and Type II ALCLs and identify BCL2 as a differentially expressed oncoprotein that might represent a target for precision therapy approaches.

Background Follicular and marginal zone B cell lymphoma (FL; MZL) demonstrate an indolent course with heterogeneous outcomes and a potential for spontaneous remissions indicating immune system intervention. T cell-based therapeutic approaches are therefore an attractive proposition in FL and MZL. EO2463 peptide immunotherapy expands pre-existing memory CD8 T cells recognizing non-self-protein sequences from gut bacteria which cross-react with B cell antigens. The compound includes 4 HLA-A2 synthetically produced epitopes which exhibit molecular mimicry with the B cell markers CD20, CD22, CD37, and CD268 (BAFF-receptor), as well as a the CD4 helper-epitope UCP2 derived from hTERT. EO2463 is being used to drive anti-tumor immunity against B cell malignancies, and has demonstrated long-lasting, specific CD8-memory T cell responses and clinical activity in relapsed/refractory FL and MZL [J Clinical Oncol 2024, 42 (S16), 7058]. Furthermore, CD8 T cells expanded from samples of patients (pts) treated with EO2463 can kill HLA-A2 expressing lymphoblastoid cell lines presenting the B cell targets [Hematological Oncol 2023, 41 (S2), 581-582]. Methods The current report describes testing of a possible biomarker in the phase 1 portion of the ongoing EONHL1-20/SIDNEY trial (NCT04669171).This part of the trial (“Cohort 1”) included pts (n=9) with relapsed (at least 1, no limit, prior treatments) FL and MZL, stage 1-3A, confirmed to be positive for HLA-A2. Pts received EO2463 (150 [n=3] or 300μg/peptide [n=6]) SC with adjuvant Montanide ISA 51 VG q2 weeks (w) x 4, then q4w, for a max of 12 months; at w7 lenalidomide (20 mg/day for 21/28 days up to 12 cycles) was added (EL), and if no complete remission (CR) at w19, rituximab (375 mg/m IV, q1w x 4, then q4w x 4) was also added (ER2). Immune responses and clinical outcomes of Cohort 1 were previously reported [J Clinical Oncol 2024, 42 (S16), 7058]. To assess a possible biomarker, tetramers were used to specifically detect CD8 T cells recognizing the 4 epitopes in the EO2463 compound (derived from gut bacterial proteins exhibiting molecular mimicry with the B cell markers CD20, CD22, CD37, and CD268). The tetramers were all marked with phycoerythrin. Thawed samples of peripheral blood mononuclear cells taken at start of w5 (after 2 administrations of EO2463 monotherapy, each followed by 2w observation) were stained ex vivo (without any in vitro stimulation) with the tetramers and assayed by flow cytometry. Results are presented as percentage of EO2463 specific CD8 T cells among all CD8 T cells in the peripheral blood of the pt. Results Among the 9 treated pts, PET-CT at w6 (after 3 administrations of EO2463 monotherapy) suggested possible clinical activity in 4/9 pts (1 PR, 1 pt size reduction 15%, 1 pt 20% reduced tracer uptake, 1 pt 5/6 target lesions reduced metabolic activity). By PET-CT at w42 (after 12 administrations of EO2463 monotherapy, 11 cycles of lenalidomide, and rituximab treatment) the Lugano response assessment was complete response in 6/9 pts. A positive biomarker response was assessed in 5/9 pts (percentage of specific CD8 T cells ranged from 0.2-2.1%). EO2463 monotherapy PET-CT activity at w6 (n=4/9 pts): 4 of 4 pts with clinical activity were biomarker positive and 1/5 of the other pts was also positive; this pt had an isolated increase in FDG-uptake at w6, followed by a CR at w19. Four further other pts were biomarker negative. In this limited sample, the biomarker had sensitivity 100% and specificity 80%. EO2463 in combination with lenalidomide/rituximab PET-CT CR at w42 (n=6/9): 5 of 6 pts with CR were biomarker positive and 1 pt with CR was negative; the pt with a negative test had no objective tumor response until after rituximab. In this limited sample, the biomarker showed sensitivity 83% and specificity 100%. Conclusions The current preliminary assessment indicates that direct ex vivo tetramer staining for specific CD8 T cells after short term (5 w) treatment with EO2463 monotherapy could be a possible biomarker for clinical response, both for EO2463 monotherapy response, and for response to EO2463 in combination with lenalidomide/rituximab. We plan to validate these findings in the ongoing study cohorts of the trial; expansion phase 2 cohorts, exploring EO2463 monotherapy in the “watch & wait” setting, EO2463 plus rituximab for 1st line FL/MZL, and EO2463/lenalidomide +/- rituximab in relapsed FL/MZL.