Therapy For Diffuse Large B-cell Lymphoma Research Articles

In Silico Discovery of a Novel PI3Kδ Inhibitor Incorporating 3,5,7-Trihydroxychroman-4-one Targeting Diffuse Large B-Cell Lymphoma.

Diffuse large B-cell lymphoma (DLBCL) is the most common lymphoma, and it is highly aggressive and heterogeneous. Targeted therapy is still the main treatment method used in clinic due to its lower risk of side effects and personalized medication. Excessive activation of PI3Kδ in DLBCL leads to abnormal activation of the PI3K/Akt pathway, promoting the occurrence and development of DLBCL. The side effects of existing PI3Kδ inhibitors limit their clinical application. The discovery of PI3Kδ inhibitors with novel structures and minimal side effects is urgently needed. This study constructed a PI3Kδ inhibitor screening model to screen natural product libraries. Revealing the mechanism of natural product therapy for DLBCL through network pharmacology, kinase assays, and molecular dynamics. The results of molecular docking indicated that Silibinin had a high docking score and a good binding mode with PI3Kδ. The results of network pharmacology indicated that Silibinin could exert therapeutic effects on DLBCL by inhibiting PI3Kδ activity and affecting the PI3K/Akt pathway. The kinase assays indicated that Silibinin concentration dependently inhibited the activity of PI3Kδ. The results of molecular dynamics indicated that Silibinin could stably bind to PI3Kδ. Silibinin was a structurally novel 3,5,7-trihydroxychroman-4-one PI3Kδ inhibitor, providing valuable information for the subsequent discovery of PI3Kδ inhibitors.

Immune reconstitution and evolution of B-cell–stimulating cytokines after R-CHOP therapy for HIV-associated DLBCL

AbstractHIV infection is associated with an increased risk of diffuse large B-cell lymphoma (DLBCL) that persists despite the advent of combined antiretroviral therapy. In this prospective study, we analyzed the evolution of B-cell activating cytokines (interleukin-6 [IL-6], IL-10, and B-cell activating factor [BAFF]) and the coevolution of main functional subsets of circulating B and T cells in 51 patients with HIV-associated DLBCL treated with R-CHOP (rituximab, cyclophosphamide, doxorubicin, Oncovin [vincristine], and prednisone). R-CHOP therapy was associated with a decrease of IL-10, whereas IL-6 levels fluctuated, and BAFF levels increased during the first 3 months and decreased thereafter. We observed a rapid rise in CD19+ B cells composed mostly of naïve B cells whereas marginal zone–like B cells and memory B cells recovered gradually. With a median follow-up of 41 months, progression-free survival and overall survival at 5 years were 61.8% (95% confidence interval [CI], 47.6-80.4) and 67.4% (95% CI, 53.4-85.0), respectively. Progression (17.5%) and sepsis (12.5%) were the main causes of death. Baseline risk factors for death and progression were poor revised International Prognostic Index (P = .049), natural killer cell lymphopenia (P = .001), lower proportion of naïve B cells among B-cell compartment (P = .017), and higher IL-6 serum levels (P = .001). Our data suggest that patients treated with R-CHOP for HIV-associated DLBCL have a disturbed peripheral B-cell compartment and that the low pool size of circulating naïve B cells negatively affects clinical outcome in these patients. In an era of rapid development of B-cell–depleting therapies including B-cell–targeting chimeric antigen receptor T cells, baseline and posttreatment assessment of perturbations within nontumoral B-cell counterparts are warranted for proper risk profiling in HIV-associated DLBCL. This trial was registered at www.ClinicalTrials.gov as #NCT01164436.

Abstract PO-034: Targeting metabolic plasticity and flexibility via SIRT3 inhibition to restrain nucleotides availability in DLBCLs

Abstract Cancer cells need metabolic adaptations to survive in hostile environment such as low nutrient and drug treatment conditions. DLBCLs (Diffuse large B cell lymphoma) originate from a metabolic competitive/challenging environment of germinal center (GC) when B cells undergo positive selections against antigens. However, it is largely unknown whether and how metabolic flexibility (the ability to use different nutrients) and plasticity (the ability to process the same nutrient differently) contribute to DLBCLs. Our previous study identified that SIRT3, the only mitochondrial protein deacetylase, is critical to survival and proliferation of DLBCLs by promoting glutaminolysis. Our mitochondrial localized SIRT3 inhibitor, YC8-02, has pan-toxicity to all DLBCL cells tested regardless of different subtypes with somatic mutations. Here, we observed glucose as an alternative nutrient source to compensate in the TCA cycle in SIRT3 deficient cells. DLBCLs exhibited resistance to SIRT3 inhibition in high glucose condition, while SIRT3 inhibited DLBCLs highly depend on glucose metabolism. The combination of YC8-02 with glucose metabolism inhibitors induces synergistic killing to DLBCLs. As glucose is the main carbon source of cells, it is unknown how DLBCLs manage the flexibility of using glucose for different purposes. Using in vivo metabolic imaging (MALDI), we observed that, in contrast to normal GC B cells, lymphomas specifically use the glucose for de novo nucleotide synthesis. SIRT3 inhibition decreased nucleotide levels in DLBCL cells in vitro and in vivo. The metabolic flux tracing showed that DLBCL cells requires SIRT3 activity to activate a glucose/serine/one-carbon metabolism pathway for de novo nucleotide biosynthesis, and Inhibition of SIRT3 decreased the glucose and serine being used for nucleotides in DLBCLs. Serine as another potent source for nucleotides can rescue DLBCLs from SIRT3 inhibition. Furthermore, we validated that overexpression of enzymes, like MTHFD2, in one carbon metabolism pathway can rescue the proliferation in SIRT3 deficient cells. High nucleotides levels in medium also help DLBCLs survival in YC8-02 treatments. To overcome the metabolic flexibility on environmental nucleotides, we used inhibitors of nucleoside transporters (ENT1/2), dipyridamole and draflazine, which can synergize with YC8-02 to kill DLBCLs in vitro and eradicate systemic lymphomas in vivo. In summary, our results illustrate that DLBCLs with active SIRT3 exhibit metabolic plasticity by repurposing glucose to nucleotide biosynthesis, while lymphoma cells can also reply on metabolic flexibility to manage nutrient usage and gain extracellular nucleotides for survival under SIRT3 inhibition. Our combination treatment SIRT3 and ENT inhibitors can be a promising therapy for DLBCLs by restraining their metabolic plasticity and flexibility. Citation Format: Meng Li, Noel R Park, Chris Chin, Coraline Mlynarczyk, Hening Lin, Shawn Davidson, Ari M Melnick. Targeting metabolic plasticity and flexibility via SIRT3 inhibition to restrain nucleotides availability in DLBCLs [abstract]. In: Proceedings of the Fourth AACR International Meeting on Advances in Malignant Lymphoma: Maximizing the Basic-Translational Interface for Clinical Application; 2024 Jun 19-22; Philadelphia, PA. Philadelphia (PA): AACR; Blood Cancer Discov 2024;5(3_Suppl):Abstract nr PO-034.

Polatuzumab vedotin in diffuse large B-cell lymphoma therapy: Literature review and experience of the Oncohematology Division of the Lapino Clinical Hospital

Study of molecular and genetic features of diffuse large B-cell lymphoma (DLBCL) suggests differential approach to treatment of this aggressive B-cell disorder characterized by short remission after each subsequent therapy line. Therefore, more effective regimens should be used at earlier stages. Identification of biological markers and their integration into prognostic scales can help to personalize therapy, especially in patients with high risk of quick progression and increase survival.Our own experience of using immunoconjugate polatuzumab vedotin in therapy of patients with DLBCL. The use of Pola-BR combination in a patient with refractory non-GCB DLBCL allowed to achieve full remission alongside satisfactory tolerability and absence of significant adverse events. An evaluation of the Pola-R-CHP regimen in treatment of a patient with newly diagnosed generalized GCB DLBCL is presented.

Outcomes in patients (pts) with relapsed/refractory (R/R) diffuse large B cell lymphoma (DLBCL) treated with systemic therapy from real world experience (ORCHID) study.

e19067 Background: Odronextamab, an off-the-shelf CD20×CD3 bispecific antibody, has shown compelling efficacy (objective response rate [ORR] 52%, complete response [CR] rate 31.5%) and a generally manageable safety profile in pts with heavily pretreated R/R DLBCL in the single-arm ELM-2 trial (NCT03888105; Ayyappan et al. ASH 2023). We evaluated outcomes in pts with R/R DLBCL treated with currently available third-line or later (3L+) therapies in a real-world setting (ORCHID; NCT05338892) to better evaluate results from ELM-2 in the absence of a randomized control arm. Methods: ORCHID is a multicenter, retrospective, observational study, using electronic medical record or research databases, of pts with R/R DLBCL who have received ≥2 prior lines of therapy (LoTs; including an anti-CD20 and an alkylator) and initiated 3L+ systemic therapy for DLBCL between January 1, 2015 and June 30, 2021. After applying similar eligibility criteria to those in the ELM-2 trial, inverse-probability of treatment weighting (IPTW) was used to balance key prognostic variables between the trial and real-world cohorts. Pts were followed from the start of qualifying LoT until death, end of study period (December 31, 2021), or loss to follow up, whichever occurred first. The primary endpoint was ORR per Lugano criteria assessed by independent central review (ICR). Secondary endpoints included ICR-assessed CR rate, disease control rate (DCR), progression-free survival (PFS), duration of response (DOR), and overall survival (OS) (see Thieblemont et al. ASH 2022). Results: Pts in ORCHID (N=148) generally had less severe disease than trial pts prior to IPTW. The most commonly used regimens were anti-CD20 based therapies, CAR T, and chemotherapy alone. The IPTW cohort had a median age 65 y, 79% Ann Arbor stage III/IV, 66% primary refractory, 88% refractory to last LoT, and median (range) prior LoT: 2 (2–6). In the IPTW cohort, ORR was 44%, CR 18%, and DCR 50%. Median (m) PFS (mPFS), DOR (mDOR), and OS (mOS) were 7.2, 9.0, and 10.8 mo, respectively. Given the lack of regular scans in routine practice (47% of pts had only one ICR response assessment over the study period), sensitivity analysis that considered subsequent treatment as progression resulted in shorter mPFS (4.6 mo) and mDOR (6.1 mo). In the majority of LoTs initiating non-CAR T therapy (n=111), ORR was 33%, CR 15%, DCR 43%. The mOS in non-CAR T group was 7.5 mo and was not reached in those intended for CAR T. Conclusions: Pts in the ORCHID study, especially those who did not receive CAR Ts, had markedly lower response rates than those in the R/R DLBCL cohort of ELM-2. Despite prior failure, most pts still received an anti-CD20 based regimen in 3L+ setting in routine practice, highlighting the need for treatment options with different mechanisms of action that provide deep and durable responses and improve outcomes in this pt population. Clinical trial information: NCT05338892 .

Abstract P04: Role of glucocorticoid receptor in normal and malignant germinal center B cells

Abstract We have reported that super-enhancers (SEs) are specifically hypermutated by Activation-Induced Deaminase (AID)-induced Aberrant Somatic Hypermutation in >90% of diffuse large B cell lymphoma (DLBCL) cases (Bal et al. Nature 2022). Analysis of 122 primary DLBCL biopsies and cell lines identified more than 80 SEs that are recurrently hypermutated, with an average of 12 hypermutated SE/case. Hypermutated SEs are predominantly linked to genes encoding regulators of B cell development and well-known lymphoma oncogenes, including BCL6, BCL2 and CXCR4. We showed that specific hotspot mutations prevent binding and transcriptional downregulation by transcriptional repressors leading to target gene dysregulation. Among these, hypermutation of the SEs linked to BCL2 and CXCR4 abrogates the binding of the glucocorticoid receptor (GR)/transcription factor encoded by NR3C1. As a result, BCL2 and CXCR4 escape GR-mediated transcriptional repression leading to their de-regulated expression in germinal center (GC) B cells. Together with the observation that the NR3C1 gene is genetically inactivated in a small fraction of DLBCL, and the relevance of glucocorticoid-based therapy in DLBCL, these results prompted a comprehensive analysis of the role of GR in normal and malignant B cells. We report that GR is detectable in the nucleus of the great majority of GC B cells, suggesting that it is active as a transcription factor. Similarly, DLBCL primary cases (including GCB-, ABC- and unclassified DLBCL) display GR nuclear expression. Analysis of a conditional GC-specific Nr3c1 knock-out (KO) mouse model showed that GC B cells form normally in the absence of Nr3c1. However, the transcriptional profile of Nr3c1-KO GC B cells was significantly altered compared to wild-type cells. By integrating the GR binding profile obtained in normal human GC B cells with the transcripts differentially expressed in Nr3c1-KO GC B cells, we identified a set of about 2,000 genes that are directly modulated by GR during the GC reaction. Pathway enrichment analysis showed that GR controls several signaling pathways, suggesting a modulatory role on the BCR and CXCR4 pathways. In addition, GR targets display a significant overlap with the BCL6 transcriptional network, suggesting a cooperative role in GC B cell development. Notably, GR was shown to regulate pathways involved in plasma cell differentiation, while repressing targets associated with memory B cell development. In DLBCL cases, several NR3C1 binding sites are recurrently targeted by mutations, suggesting that genetic impairment of GR activity is heterogeneous and extends beyond CXCR4 and BCL2. Together, these data support a role for the glucocorticoid pathway in GC physiology. Recurrent inactivation of the NR3C1 gene or part of its transcriptional regulatory program may contribute to DLBCL pathogenesis, with implications for presently unknown specific roles of glucocorticoids in the therapeutic regimens for DLBCL. Citation Format: Clarissa Corinaldesi, Antony B Holmes, Elodie Bal, Laura Pasqualucci, Katia Basso, Riccardo Dalla-Favera. Role of glucocorticoid receptor in normal and malignant germinal center B cells [abstract]. In: Proceedings of the Blood Cancer Discovery Symposium; 2024 Mar 4-6; Boston, MA. Philadelphia (PA): AACR; Blood Cancer Discov 2024;5(2_Suppl):Abstract nr P04.

A promising natural product in diffuse large B-cell lymphoma therapy by targeting PIM1.

Diffuse large B-cell lymphoma (DLBCL) is the most common and aggressive type of B-cell lymphoma. Unfortunately, about one-third of patients either relapse after the initial treatment or are refractory to first-line therapy, indicating a need for new treatment modalities. PIM serine/threonine kinases are proteins that are associated with genetic mutations, overexpression, or translocation events in B-cell lymphomas. We conducted an integrative analysis of whole-exome sequencing in 52 DLBCL patients, and no amplification, mutation, or translocation of the PIM1 gene was detected. Instead, analyses of TCGA and GTEx databases identified that PIM1 expression was increased in DLBCL samples compared to normal tissue, and high expression levels were associated with poor overall survival. Moreover, interference of PIM1 significantly suppressed DLBCL cell proliferation. In addition, we identified anwulignan, a natural small-molecule compound, as a PIM1 inhibitor. Anwulignan directly binds to PIM1 and exerts antitumor effects on DLBCL in vitro and in vivo by inducing apoptosis, cell cycle arrest, and autophagic cell death. Furthermore, we identified an effective synergistic combination between anwulignan and chidamide. Our findings suggested that PIM1 could be a therapeutic target and prognostic factor for DLBCL, and anwulignan holds promise for future development as a natural product for treatment.

MYC-dependent MiR-7-5p regulated apoptosis and autophagy in diffuse large B cell lymphoma by targeting AMBRA1.

Diffuse large B-cell lymphoma (DLBCL) is the leading cause of mortality from invasive hematological malignancies worldwide. MicroRNA-7-5p (miR-7-5p) has been shown to be a tumor suppressor in several types of tumors. However, its role in DLBCL is not fully understood. This study explored the role of miR-7-5p in the progression of DLBCL and pursued the underlying mechanism. Quantitative real-time PCR and transfection of miRNA mimic and inhibitors were used to assess the effects of miR-7-5p on autophagy and apoptosis in SU-DHL-4 and SU-DHL-10 cells. Dual-luciferase reporter assay was used to identify target genes of miR-7-5p. Immunofluorescence, flow cytometry, and western blotting (WB) were performed to explore the underlying mechanism and downstream pathways of miR-7-5p and AMBRA1 in DLBCL cells. MiR-7-5p was upregulated in DLBCL cells. Luciferase reporter assays implicated AMBRA1 as a downstream target of miR-7-5p in DLBCL. WB and flow cytometry showed that an increase in miR-7-5p level and a decrease in AMBRA1 expression led to a decrease in autophagy and apoptosis-related protein expression. Furthermore, miR-7-5p prevented c-MYC dephosphorylation through AMBRA1 downregulation. On the contrary, c-MYC increased the expression of miR-7-5p, thereby establishing positive feedback on miR-7-5p transcription. The addition of hydroxychloroquine, an autophagy inhibitor, reduced autophagy and increased apoptosis in DLBCL cells. In vivo experiments further proved that the increase of miR-7-5p played a regulatory role in the expression of downstream AMBRA1 and c-MYC. These results demonstrate that c-MYC-dependent MiR-7-5p suppressed autophagy and apoptosis by targeting AMBRA1 in DLBCL cells. MiR-7-5p also suppressed autophagy and apoptosis by targeting AMBRA1 in DLBCL cells. Therefore, these data suggest that targeting miR-7-5p may be a promising strategy in DLBCL therapy.

Значение ПЭТ, совмещенной с КТ, при диффузной В-крупноклеточной лимфоме: история вопроса, эволюция представлений и современные возможности метода (обзор литературы)

Combined positron emission tomography/computed tomography (PET/CT) is broadly used not only during initial staging of non-Hodgkin lymphomas (NHL) but also during as well as after treatment. Due to an increasing body of accessible data on classical Hodgkin lymphoma revealing high significance of PET/CT, the amount of relevant information on NHL is also growing day by day. At the moment, there is a consensus that PET/CT results can be effectively used in prognostic risk stratification of patients with different NHL variants, including diffuse large B-cell lymphoma (DLBCL). However, a huge volume of information collected by now hinders a full insight because of clinical variability of DLBCL, different time-points and methods of evaluating PET/CT results. The present review focuses on the role of PET/CT in the diagnosis and assessment of response to DLBCL therapy.

Treatment of Diffuse Large B-Cell Lymphoma at the Moscow City Clinical Hospital No. 52: A Retrospective Clinical Trial Based on the Single-Center Experience and Analysis of Data from Its In-House Registry

Background. The term diffuse large B-cell lymphoma (DLBCL) defines a heterogeneous group of lymphatic tumors. DLBCL is the most frequent immunomorphological variant among aggressive non-Hodgkin lymphomas (NHLs) in adults. It accounts for 30–40 % of all NHLs. Long-term results of treating newly diagnosed DLBCL have not been reliably evidenced in healthcare practice and, therefore, require further study.
 Aim. To assess the efficacy of chemotherapy for newly diagnosed DLBCL in terms of the 5-year progression-free survival (PFS) based on the analysis of data from the in-house hematology service registry at the Moscow City Clinical Hospital No. 52.
 Materials & Methods. The study enrolled 156 patients with newly diagnosed DLBCL in the period from 2015 to 2022. The patients were 35–85 years of age (median 65 years).
 Results. First-line R-CHOP/R-miniCHOP chemotherapy was administered to 70 % of patients, 28 % of patients received R-DA-EPOCH, and 2 % were treated either with R-B or R-CVP. Complete response was achieved in 100 (65 %) patients: 75 out of them (75 %) received R-CHOP/R-miniCHOP, whereas 25 (25 %) received R-DA-EPOCH. Induction mortality was below 2.5 %. The 5-year PFS was 32 % with the survival median of 20 months. As confirmed by the multivariate analysis, the age over 60 years (p = 0.003), high IPI risk group (p = 0.015), advanced stage of the disease (p = 0.002), and non-GCB subtype of tumor (p = 0.045) can be regarded as independent predictors of early DLBCL progression.
 Conclusion. DLBCL is an aggressive B-cell lymphoma and one of the most frequent immunomorphological NHL variants in the clinical practice of the Moscow City Clinical Hospital No. 52. Despite the use of generally accepted standard immunochemotherapy regimens, the results attained by the present study illustrate unresolved challenges in chemotherapy for newly diagnosed DLBCL patients. By now, more effective first-line DLBCL therapy methods already exist, which are confirmed by the results of clinical trials. As it is sometimes impossible to further escalate immunochemotherapy for obvious reasons (age restrictions, health status, co-morbidities, etc.), a new promising strategy appears to be the personalized chemotherapy based on the study of genetic DLBCL profile of each particular patient.

Diffuse large B-cell lymphoma: the significance of CD8+ tumor-infiltrating lymphocytes exhaustion mediated by TIM3/Galectin-9 pathway

BackgroundOverexpression of T-cell immunoglobulin and mucin domain-containing protein 3 (TIM3) is related to the exhaustion of CD8+ tumor-infiltrating lymphocytes (TILs) in diffuse large B-cell lymphoma (DLBCL). However, the mechanism of TIM3-mediated CD8+TILs exhaustion in DLBCL remains poorly understood. Therefore, we aimed to clarify the potential pathway involved in TIM3-mediated CD8+TILs exhaustion and its significance in DLBCL.MethodsThe expression of TIM3 and its correlation with CD8+TILs exhaustion, the key ligand of TIM3, and the potential pathway of TIM3-mediated CD8+TILs exhaustion in DLBCL were analyzed using single-cell RNA sequencing and validated by RNA sequencing. The biological significance of TIM3-related pathway in DLBCL was investigated based on RNA sequencing, immunohistochemistry, and reverse transcription-quantitative polymerase chain reaction data. Finally, the possible regulatory mechanism of TIM3-related pathway in DLBCL was explored using single-cell RNA sequencing and RNA sequencing.ResultsOur results demonstrated that CD8+TILs, especially the terminally exhausted state, were the major clusters that expressed TIM3 in DLBCL. Galectin-9, mainly expressed in M2 macrophages, is the key ligand of TIM3 and can induce the exhaustion of CD8+TILs through TIM3/Galectin-9 pathway. Meanwhile, high TIM3/Galectin-9 enrichment is related to immunosuppressive tumor microenvironment, severe clinical manifestations, inferior prognosis, and poor response to CHOP-based chemotherapy, and can predict the clinical efficacy of immune checkpoint blockade therapy in DLBCL. Furthermore, the TIM3/Galectin-9 enrichment in DLBCL may be regulated by the IFN-γ signaling pathway.ConclusionsOur study highlights that TIM3/Galectin-9 pathway plays a crucial role in CD8+TILs exhaustion and the immune escape of DLBCL, which facilitates further functional studies and could provide a theoretical basis for the development of novel immunotherapy in DLBCL.

Identification of a 16-MTGs Prognostic Signature in Diffuse Large B-Cell Lymphoma

Background. Diffuse large B-cell lymphoma (DLBCL) is one of the largest lymphoma subcategories. Usually, 50%–70% of DLBCL patients can be cured by the standard treatment. But, at least one third have bad prognosis. Based on this situation, the research on DLBCL therapy strategy is still indispensable. Methods. A prognostic signature was built according to the public data and bioinformatics methods, the stability and reliability was assessed and validated. GSEA was performed to explore the difference in different groups. Consensus clustering and immune infiltration analysis were conducted comprehensively. Results. In this work, a signature based on multiple metabolism-associated genes (MTGs) was established, containing 16 MTGs, to predict the prognosis of DLBCL patients. The accuracy and effectiveness of this signature have been verified by three external validation sets. According to the risk formula, DLBCL patients were divided into high- and low-risk groups, and the survival rate of the low-risk group was significantly higher than that of the high-risk group. Furthermore, gene set enrichment analysis (GSEA) demonstrated that beta-alanine metabolism and regulation of actin cytoskeleton signal pathways were enriched in the low-risk group. The actual survival and nomogram-predicted survival matched well both in the training cohort and verification cohorts. Conclusion. In general, our prognostic signature can provide reliable and valuable information for medical workers in predicting the prognosis of DLBCL. A preprint was made available by the research square in the following link: “https://www.researchsquare.com/article/rs-1468741/v2.”

Current development of chimeric antigen receptor T-cell therapy for diffuse large B-cell lymphoma and high-grade B-cell lymphoma.

Chimeric antigen receptor (CAR) T-cell therapy has become a commercially available treatment option for relapsed or refractory (r/r) diffuse large B-cell lymphoma (DLBCL) with two or more lines of prior therapies, and recently for high-risk r/r DLBCL with one prior line of therapy. The successful development of CAR T-cell therapy for multiple relapsed DLBCL has led to a boom in subsequent trials that investigated its utility in patients with other r/r B-cell lymphoma subtypes. However, CAR T-cell therapy is a multistep process that includes leukapheresis and manipulation which take several weeks. Therefore, patients with rapidly progressing or bulky disease may not be able to complete the therapeutic regimen involving CAR T-cell products. This raises the question of the generalizability of the results of pivotal studies to the entire population. In this review, we summarize the development of CAR-T cell therapy for B-cell lymphoma and discuss strategies to further improve the clinical outcomes of this treatment.

Targeting HDACs for diffuse large B-cell lymphoma therapy

Histone deacetylases (HDACs) are involved in tumorigenesis and progression, however, their role in diffuse large B-cell lymphoma (DLBCL) is not well understood. In this study, we examined the expression levels, mutations, and clinical significance of HDACs in DLBCL. Additionally, we investigated the therapeutic potential of Chidamide, a novel HDAC inhibitor, to provide scientific evidence for targeting HDACs in DLBCL patients. We extracted transcriptome data of DLBCLs––including 47 lymph node samples and 337 whole-blood-cell controls––from The Cancer Genome Atlas. Bioinformatic analyses of HDAC expression, mutation, and correlation with the clinical significance of DLBCL patients were performed with the Gene Expression Profiling Interactive Analysis, GENEMANIA, and web-based software including cBioPortal and WebGestalt. To examine the therapeutic effect of Chidamide, DLBCL cell lines (WSU-DLCL-2 and DB cells) were employed. Cell proliferation and apoptosis were analyzed with Cell Counting Kit-8 and flow cytometry assays. The impact of Chidamide treatment was also analyzed by RNA sequencing of treated DB cells. Western blot was used to explore the molecular mechanism of the cytotoxicity of Chidamide on DLBCL cell lines. The expression of some HDACs (HDAC1, 2, 3, 4, 6, 7, 8, and 9) were significantly higher in the lymph node samples of DLBCL than that in whole-blood-cell controls. Moreover, we found that the mutation rate of HDACs was also higher in DLBCL tissues, although the overall survival of DLBCL patients was not associated with HDAC expression. Chidamide was found to have a cytotoxic effect on DLBCL cells in a dose-dependent manner, while transcriptome analysis and western blot revealed that using it for treatment impacted several biological processes, including PI3K/AKT signaling, mTOR signaling, the cell cycle, and apoptosis pathways. Alterations of HDAC genes, including enhanced expression and mutations, are positively related to DLBCL. Targeting HDACs with specific inhibitors such as Chidamide may represent a potential therapeutic approach for DLBCL patients.

CD5 Gene Signature Identifies Diffuse Large B-Cell Lymphomas Sensitive to Bruton's Tyrosine Kinase Inhibition.

A genetic classifier termed LymphGen accurately identifies diffuse large B-cell lymphoma (DLBCL) subtypes vulnerable to Bruton's tyrosine kinase inhibitors (BTKis), but is challenging to implement in the clinic and fails to capture all DLBCLs that benefit from BTKi-based therapy. Here, we developed a novel CD5 gene expression signature as a biomarker of response to BTKi-based therapy in DLBCL. CD5 immunohistochemistry (IHC) was performed on 404 DLBCLs to identify CD5 IHC+ and CD5 IHC- cases, which were subsequently characterized at the molecular level through mutational and transcriptional analyses. A 60-gene CD5 gene expression signature (CD5sig) was constructed using genes differentially expressed between CD5 IHC+ and CD5 IHC- non-germinal center B-cell-like (non-GCB DLBCL) DLBCLs. This CD5sig was applied to external DLBCL data sets, including pretreatment biopsies from patients enrolled in the PHOENIX study (n = 584) to define the extent to which the CD5sig could identify non-GCB DLBCLs that benefited from the addition of ibrutinib to rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP). CD5 expression was observed in 12% of non-GCB DLBCLs. CD5+ DLBCLs displayed transcriptional features of B-cell receptor (BCR) activation and were enriched for BCR-activating mutations known to correlate with BTKi sensitivity. However, most CD5+ DLBCLs lacked canonical BCR-activating mutations or were LymphGen-unclassifiable (LymphGen-Other). The CD5sig recapitulated these findings in multiple independent data sets, indicating its utility in identifying DLBCLs with genetic and nongenetic bases for BCR dependence. Supporting this notion, CD5sig+ DLBCLs derived a selective survival advantage from the addition of ibrutinib to R-CHOP in the PHOENIX study, independent of LymphGen classification. CD5sig is a useful biomarker to identify DLBCLs vulnerable to BTKi-based therapies and complements current biomarker approaches by identifying DLBCLs with genetic and nongenetic bases for BTKi sensitivity.

Geographic and Racial Disparities in Chimeric Antigen Receptor-T Cells and Bispecific Antibodies Trials Access for Diffuse Large B-Cell Lymphoma

Introduction: The number of clinical trials of chimeric antigen receptor T- cell (CAR-T) therapy and bispecific antibodies to treat diffuse large B-cell lymphoma (DLBCL) has increased exponentially. However, there is geographic limitation to offering these trial and universal access appears to be limited especially for minorities and those in low socioeconomic stratum. Here, we investigate the geographical and racial disparities in accessing CAR-T cell therapy and bispecific antibodies trials for DLBCL. Methods: Data on clinical trials were obtained from ClinicalTrials.gov, the largest clinical trials registry database that provides data on clinical trials that are completed or in process. We searched ClinicalTrials.gov in May 2023 using the terms diffuse large B-cell lymphoma, DLBCL, CAR-T, chimeric antigen receptor T cells, chimeric, bispecific antibodies, bispecific, BCMA, and T-cell engager. All available trials listed as completed, recruiting, active-nonrecruiting, terminated, or suspended. The collected data abstracted from ClinicalTrials.gov included study titles, National Clinical Trial identification numbers, trial phase and intervention, actual or expected number of participants (in studies that did not complete enrollment), primary outcomes, recruiting sites, funders, and specific inclusion and exclusion criteria. 2020 United States (US) Census Bureau data was used to obtain data on race and ethnicity. Analysis for this study was performed using SPSS version 26. Results: A total of 76 out of 133 clinical trials with one or more open site in the US were included for this systematic review. There were 63 (82.9%) CAR-T therapy and 13 (17.1%) bispecific antibodies trials. A total of 166823 participants were either enrolled or expected to enroll in these clinical trials including 165938 (99.5%) of CAR-T and 885 (0.5%) bispecific antibodies clinical trials participants. Sixty-five (85.5%) clinical trials were only open in the US while 11 (14.5%) clinical trials were open in the US and other countries. The majority of the trials 49 (64.5%) were funded by the industry, while 27 (35.5%) were non-industry sponsored. The primary outcomes of the studies were safety related, efficacy related, and both safety and efficacy related in 43 (56.6%), 22 (28.9%), and 11 (14.5%) trials, respectively. One hundred and twenty-six unique study sites for the 76 analyzed clinical trials were identified. The mean number of sites per trial were 4.5 (1-26) for CAR-T trials and 4.4 (1-24) for bispecific antibodies. The study sites were distributed in 31 different states and mean number of trial per state were 11 (0-51). Most sites for trials were in Southern states 39 (31%), followed by Midwestern 32 (25.4%), Northeastern 30 (23.8%), and Western states 25 (19.8%). The highest number of study locations were in California (13), New York (9), and Pennsylvania (9) while the highest number of open studies were in California (51), Texas (32), and New York (23). Twenty states had no open CAR-T or bispecific antibodies clinical trials including three in the Northeast (Maine, Rhode Island, and Vermont), three in the Midwest (Indiana, North and South Dakota), seven in the South (Delaware, District of Columbia, West Virginia, Mississippi, Arkansas, Louisiana, and Oklahoma), and seven in the West (Idaho, New Mexico, Montana, Nevada, Wyoming, Alaska, and Hawaii). (Figure 1A) Using Census Bureau data, only 33.3% of the African American (AA) (13 669 915 of 41 104 200) lived in a county with a CAR-T or bispecific antibodies trial. There were only six states (12%) with 50% or more of the AA population living in a county with an open CAR-T or bispecific antibody trial and 15 states (29%) with 30% or more of their AA county residents. Seven out of ten states with the highest proportion of AA residents (18.6%-41.4%) have no (four states) or less than four clinical trial sites (three states) for either CAR-T or bispecific antibodies. (Figure 1B) Conclusion: There is significant geographic and racial disparity in accessing CAR-T cell therapy and bispecific antibodies trials for DLBCL. Strategies should be framed to address the causes for the observed disparities and to improve access.

A Phase Ib Study to Evaluate the Safety and Efficacy of Nivolumab in Combination with R-CHOP in High-Risk DLBCL

Introduction Chemoimmunotherapy with R-CHOP is an established standard of care for diffuse large B-cell lymphoma (DLBCL) but is not curative in all patients (pts). Approximately 20% of DLBCL have aberrations involving the PD-L1/PD-L2 locus. This justifies the investigation of PD-1 checkpoint inhibitors in pts with DLBCL. This Phase 1b study was conducted to determine the maximum tolerated dose (MTD) for nivolumab in combination with R-CHOP in pts with DLBCL and to evaluate the preliminary efficacy of the regimen. Methods Patients with newly diagnosed de novo DLBCL or transformed low-grade lymphoma (tLL) were enrolled from 2019-2022. Treatment comprised a lead-in phase (LIP) with nivolumab 240 mg x 1 followed 2 weeks later by combination nivolumab-R-CHOP given every 3 weeks for 6 cycles. For combination therapy, nivolumab was administered on Day 1 followed by R-CHOP on Days 1-5 (Days 2-6 for Cycle 1). To establish MTD with Phase 1, nivolumab dosing followed a modified 3+3 dose escalation, starting with 1 mg/kg (dose level 1), escalating to 240 mg (dose level 2). MTD was administered for the Phase Ib portion of the study. Primary endpoints were determination of MTD and rate of complete metabolic response (CMR) by PET/CT using Lugano 2014 as best response by completion of 6 cycles of combination therapy (EOT). Correlations of immune subsets with durability of response and toxicity were exploratory. Results Thirty-three patients were enrolled, of which 25 and 22 pts were evaluable for toxicity and efficacy, respectively. The majority were men (n=21, 64%), White (n=26, 79%) with ECOG performance status of 0-1 (n=30, 91%). Twenty-seven (82%) had advanced stage and/or intermediate/high risk IPI score and 20 (65%) had germinal center subtype. Fifteen (45%) and 16 (48.5%) had tLL (2 with prior therapy for LL prior to transformation) and MYC aberrancy (13 with gains; 2 with single-hit and 1 with double-hit rearrangements), respectively. A dose of 240 mg of nivolumab was established as MTD. Twenty of 22 (91%) achieved CMR and 2 partial metabolic response (PMR) by EOT with overall response in 100%. One pt died from COVID-19 after 4 cycles but was in CMR on interim imaging. With median follow-up of 12 months (mo), 4 pts had progression. Both pts with PMR by EOT have not relapsed. Estimated 18-mo OS & PFS were 95.4% & 71.6%, respectively. Correlation of PFS with PD-L1 expression is underway. Most common therapy-related adverse events (TRAEs) attributed to nivolumab-R-CHOP were fatigue in 22 (88%), HTN in 21 (84%), lymphopenia in 21 (84%), and neutropenia in 18 (72%). High-grade (grade 3/4) neutropenia occurred in 15 (60%) with growth factor use per discretion of treating physician. Fifteen (60%) pts had infections, 47% high-grade. Immunotoxicities (IT) were the most common TRAEs attributed to nivolumab in 18 pts (72%), including thyroiditis (n=5, 20%), dermatitis (n=4, 16%), hepatitis (n=3, 12%), and infusion reactions (n=3, 12%). Most common high-grade IT: 1 case each of colitis, hepatitis, myocarditis (discontinued nivolumab), and dermatitis (discontinued nivolumab). For biologic correlates (Figures 1 & 2): non-progressors (NP) were enriched for T regulatory cell (e.g., IFN-γ producing CD4+Foxp3+ phenotype) fragility while progressors (PD) were enriched for exhausted T cell immunophenotype (CD4+PD-1+CD39+) prior to both LIP and initiation of combination therapy (C1D1). Furthermore, exhausted-like T cell levels were significantly reduced at C1D1 in comparison to LIP in NP but not PD. Toxicities correlated to less exhausted-like effector T cell phenotype, decreased CD4+ naïve and central memory T cells, and increased circulating B cells and myeloid-derived suppressor cells. Conclusions This study demonstrates promising efficacy of frontline combination nivolumab-R-CHOP for high-risk DLBCL including pts with intermediate/high risk IPI, tLL, and MYC aberrancy. While limited by small sample size, this regimen resulted in response, PFS, and OS rates above historical rates reported in high-risk pts and provides basis for further evaluation of nivolumab-based therapies in such pts. We found correlations between progression, toxicity and specific immune subset populations. Attention to these biologic correlates as predictors of durable response and toxicity may allow for better patient selection to optimize benefits of therapeutic effect and risks of increased toxicity with nivolumab-based therapies in DLBCL.

Early and Sustained Circulating Tumor DNA Response Dynamics after Loncastuximab Tesirine for Relapsed/Refractory Diffuse Large B-Cell Lymphoma

Introduction: Circulating tumor DNA (ctDNA) has emerged as a tool to characterize tumors and track minimal residual disease (MRD) in many malignancies, including diffuse large B-cell lymphoma (DLBCL). ctDNA levels have been shown as prognostic after first-line treatment and CD19-targeted chimeric antigen receptor (CAR19) T cell therapy in DLBCL. Loncastuximab tesirine (loncastuximab tesirine-lpyl [Lonca]), an antibody-drug conjugate comprising an antibody targeting CD19 and a pyrrolobenzodiazepine dimer cytotoxin, is approved for relapsed/refractory (R/R) DLBCL. The ultrasensitive ctDNA-MRD detection method, phased variant enrichment and detection sequencing (PhasED-Seq) was applied to evaluate molecular response and mutational genotypes in patients (pts) undergoing Lonca treatment. Methods: LOTIS-2 study (NCT03589469) evaluated the efficacy of Lonca in R/R DLBCL after ≥ 2 lines of prior systemic therapy. Samples from 33 LOTIS-2 pts were profiled by PhasED-Seq (Foresight Diagnostics), representing a range of best responses to therapy, including 8 complete response (CR), 14 partial response (PR), and 11 progressive disease (PD). Pts received a median of 4 treatment cycles with Lonca (range 2-22). Baseline plasma and peripheral blood mononuclear cells were used to identify tumor-specific phased variants (PVs), which were used to monitor ctDNA-MRD after 1 cycle of treatment (cycle 2, day 1 [C2D1]) and at the end of treatment (EOT). Samples were reported quantitatively with levels of ctDNA-MRD and qualitatively as ctDNA-MRD positive or negative. Absolute ctDNA levels and log-fold change (LFC) in ctDNA were compared with outcomes including best overall response, progression-free survival (PFS), and overall survival (OS), as determined by the independent review committee. The ctDNA mutational profile of each pt was evaluated at baseline and EOT to assess emerging clonal alterations with emphasis on CD19. Results: PVs were successfully genotyped from pretreatment plasma in 31/33 pts (94%) with sufficient material for analysis. The median pretreatment ctDNA level was 141 haploid genome equivalents /mL (hGE/mL) (range 0.4-3608), similar to previous DLBCL studies in first-line and relapsed settings. Interestingly, pretreatment ctDNA levels were not predictive of outcomes to treatment (hazard ratio [HR] 0.99, P=0.96). The prognostic value of ctDNA levels was assessed at C2D1. Absolute ctDNA levels and the change from baseline levels were significantly prognostic for the response to treatment. Pts achieving either a CR or a PR had significantly greater reduction in their ctDNA levels than those failing to respond (CR vs PD, median LFC -1.5 vs 0.1, P=0.001; PR vs PD, median LFC -1.1 vs 0.1, P=0.006) (Fig 1A). Interestingly, pts achieving a CR or a PR did not have significantly different changes in ctDNA at C2D1 ( P=0.15). When dividing pts at the median into those with high vs low ctDNA levels at C2D1, lower levels of ctDNA were significantly associated with superior PFS and OS (PFS: HR 4.4, P=0.009; OS: HR 3.2, P=0.01) (Fig 1B). At the EOT, 5 of 6 CR pts had cleared their ctDNA-MRD to undetectable levels vs 1 of 6 at C2D1. The CR pt who did not show deepening of molecular response was the only CR pt who ended Lonca treatment for radiographic disease progression; all other CR pts ended treatment for other reasons (e.g., toxicity, transplant, or persistent complete remission). To assess for emergent clonal mutations, the mutational profiles of pts were evaluated before Lonca treatment and at EOT. Prior studies in DLBCL after CAR19 T-cell therapy have revealed recurrent, although infrequent, mutations in CD19 as a mechanism of resistance. In this cohort, no emergent alterations in CD19 at the EOT (0/31 pts) were observed. One pt was identified with a baseline mutation in CD19 (R363C); this pt achieved a PR followed by PD after 3 cycles of treatment with persistence of the mutation in CD19. Conclusions: ctDNA molecular response assessment using PhasED-Seq is prognostic for outcomes in pts receiving Lonca monotherapy. ctDNA levels as early as C2D1 can predict outcomes and are indicative of a fast response to Lonca. Furthermore, molecular responses can deepen with additional cycles. CD19 alterations do not appear to be a common emergent mechanism of resistance to Lonca. In this exploratory study, ctDNA-MRD predicts Lonca efficacy and outcomes and should be further considered as a universal biomarker in DLBCL.

Overall Survival Following First and Second Relapse of DLBCL Treated with Therapies Including Autologous Transplant and CAR-T Cells: Results from the Lion Prospective Observational Registry

Background: Diffuse large B cell lymphoma (DLBCL) is the most common subtype of aggressive non-Hodgkin lymphoma (NHL) and is curable with first-line conventional chemotherapy, but a significant fraction of patients relapse or do not respond to initial therapy. There are a variety of treatments available for relapsed/refractory (RR) disease, including platinum-based salvage chemotherapy often used historically both with or without autologous stem cell transplant, and chimeric antigen receptor T-cell (CAR-T) therapy emerging more recently as a second-line option. We report survival data following 2 nd and 3 rd line therapy for RR DLBCL in a large contemporary prospective cohort. Methods: We selected patients (pts) from the Lymphoma Innovations ORIEN Network (LION) with diffuse large B-cell lymphoma, not otherwise specified and high-grade B-cell lymphoma with MYC and BCL2 and/or BCL6 rearrangements (“double-hit” lymphoma) who had previously received R-CHOP chemotherapy. All patients had signed written consent. Clinical data were abstracted from medical records using standardized protocol. Overall survival was estimated using Kaplan-Meier and defined as time from start of 2 nd (OS2) or 3 rd (OS3) line treatment until death, censoring patients alive at last follow-up. Comparisons of OS were performed using the log-rank test. Results: A total of 328 patients with RR DLBCL who received 2 nd line treatment were included, 177 of whom went on to receive 3 rd line therapy. Baseline characteristics included male sex in 205 pts (65%), stage III/IV disease in 244 pts (81%), and extranodal involvement in 183 pts (63%). Second line treatments included platinum-based salvage chemotherapy both with (99 pts) and without (88 pts) autologous stem cell transplant, rituximab plus gemcitabine and oxaliplatin (30 pts, grouped distinctly from platinum-based salvage chemotherapy), CAR-T therapy (43 pts), polatuzumab vedotin (17 pts), and other classes of treatment (51 pts). Median OS2 for 2 nd line platinum-based salvage chemotherapy with autologous transplant was 110.4 months compared with 50.4 months for platinum-based salvage chemotherapy without transplant. OS2 for platinum-based salvage chemotherapy with autologous transplant was 96.5% (95% CI 90-99) at 12 months, 90.7% (95% CI 81-96) at 24 months, and 79.3% (95% CI 67-88) at 60 months compared with 77.1% (95% CI 66-85) at 12 months, 65.5% (95% CI 52-76) at 24 months, and 38.1% (95% CI 21-55) for platinum-based salvage without transplant. OS2 for rituximab plus gemcitabine and oxaliplatin was 81.7% (95% CI 58-93) at 12 months, still 81.7% (95% CI 58-93) at 24 months, and 70.1% (95% CI 37-88) at 60 months. OS2 for CAR-T cell therapy was 75% (95% CI 50-89) at 12 months and 62.5% (95% CI 36-80) at 24 months, it could not be calculated at 60 months. OS2 for polatuzumab vedotin was 73.5% (95% CI 36-91) at 12 months and could not be calculated at 24 or 60 months. OS3 for platinum-based salvage chemotherapy with autologous transplant was 100% at 12 months and 83.3% (95% CI 27-98) at 24 months compared with 70.7% (95% CI 34-90) at both 12 and 24 months for platinum-based salvage without transplant. OS3 for rituximab plus gemcitabine and oxaliplatin was 75% (95% CI 13-96) at 12 months and 50% (95% CI 6-85). OS3 for CAR-T therapy was 86.3% (95% CI 75-93) at 12 months, 65.8% (95% CI 50-78) and 46.3% (95% CI 22-68) at 60 months. OS3 for polatuzumab vedotin was 53.4% (95% CI 24-76) at 12 months and 40.1% (95% CI 12-67) at 24 months. Conclusions: We observed a statistically significant difference by log-rank in OS2 in patients receiving platinum-based salvage chemotherapy followed by autologous stem cell transplant compared to other therapies in a contemporary cohort of pts with RR DLBCL. This difference is likely driven in part by transplant being a surrogate marker for efficacy of salvage chemotherapy. OS3 was also highest at 12, 24, and 60 months in patients receiving platinum-based salvage chemotherapy followed by transplant. Other therapies including CAR-T cells, polatuzumab vedotin, and rituximab plus gemcitabine and oxaliplatin did not demonstrate significantly different rates of overall survival in the 2 nd or 3 rd line setting.

Optimizing Circulating Tumor DNA Limits of Detection for DLBCL during First Line Therapy

Background: Circulating tumor DNA (ctDNA) assessment is effective in diffuse large B-cell lymphoma (DLBCL) monitoring and risk stratification, with prognostic utility throughout first-line (1L) therapy. DLBCL ctDNA assays vary in analytical sensitivity, or limit of detection (LOD), which range from parts per thousand to below 1 part per million (1 in 10 6). With differing assays and time-points assessed in DLBCL studies, the relationship between analytical and clinical sensitivity for outcome prediction remains unclear. We assessed the prognostic ability of ctDNA at various LODs and used modeling strategies to project the efficacy of assays for minimal residual disease (MRD) detection. Methods: We previously reported a DLBCL dataset assessing plasma ctDNA before, during and after curative-intent 1L anthracycline-based treatment from multiple prospective studies, including RCHOP or EP[O]CH with acalabrutinib, lenalidomide, obinutuzumab, and polatuzumab (Roschewski et al. ASH 2022). In this study, ctDNA was evaluated by Phased Variant Enrichment Detection and Sequencing (PhasED-Seq, Foresight Diagnostics), a ctDNA MRD assay with LOD below 1 in 10 6. Samples from this study and a prospective DLBCL cohort treated with standard 1L therapy at Samsung Medical Center were considered in this analysis. We assessed the prognostic ability of ctDNA detection, considering LODs from 1 in 100 (10 2)to 1 in 10 6 to predict progression free survival (PFS) before, during and after 1L treatment. We assessed the desired sensitivity for ctDNA MRD during treatment by generating patient-specific log-linear models assuming exponential decay. We projected the distribution of variant allele frequencies (VAFs) during therapy from cycles 2 to 5 for patients who progressed to determine the minimal acceptable analytical sensitivity. Results: We included 230 patients consisting of 588 ctDNA samples, with 201 before therapy, 71 at C2D1, 101 at C3D1, 70 at C4D1 and 145 at end of therapy (EOT). Median follow-up was 17.5 months and 62 patients (27%) progressed. To evaluate the impact of LOD at treatment milestones, we applied a threshold for ctDNA positivity ranging from 1 in 10 2 to 1 in 10 6. Increased LOD had no effect on the performance of ctDNA before therapy (Figure A & B). At C2D1, if the LOD was at least 1 in 10 4, there was no difference in MRD prognostic performance. Starting at C3D1, improving the LOD for ctDNA positivity down to 1 in 10 6 showed superior predictive power for PFS at 24 months. The power of ctDNA to predict PFS at 24 months improved later in therapy, with area under the receiver operator curves (AUROCs) for PFS24 of 0.68, 0.73, 0.77, 0.88, and 0.86, at pretreatment, C2D1, C3D1, C4D1, and EOT time-points respectively (Figure A). To further understand the desired LOD for ctDNA MRD, we developed personalized models of ctDNA VAFs. Exponential models fit the data well in 43/44 cases with ≥ 3 MRD-detectable samples through C4D1, with a median correlation of 0.91, confirming their utility for modeling ctDNA. We generated log-linear models for 106 patients with ≥ 2 MRD-detectable samples, and used log-fold change in VAF per cycle (i.e. the slope) to compare patients by progression. Median log-fold change in VAF per cycle was worse for patients who progressed at -1.1 (IQR -1.4, -0.7) compared to those who remained disease-free with median -1.5 (IQR -2.0, -1.1) (p<0.0001). Patients with primary refractory DLBCL on EOT imaging had less robust log-fold change per cycle with median of -0.9 (IQR -1.3, -0.5) compared to those who relapsed after CR with median -1.3 (IQR -1.7, -0.9) (p=0.0004). We used the distribution of slopes to project VAFs for cycles 2 to 5 for patients who progressed to determine the LODs that provide acceptable clinical sensitivity. We found the analytical sensitivity for detecting DLBCL extended lower for each cycle, demonstrating the need for a LOD at least 1 in 10 6 for robust MRD detection at late time-points during 1L treatment. Conclusion: When using an ultrasensitive assay, MRD assessment at later timepoints better predicts PFS than at early timepoints. While the technical LOD does not affect disease burden assessment before therapy, using more sensitive assays during and after therapy improves disease detection and outcome prediction. Utilizing the most sensitive ctDNA MRD assays in 1L DLBCL therapy will maximize the efficacy of MRD-driven therapeutic strategies and MRD as a surrogate endpoint in future trials.