Subtype Of Lymphoma Research Articles

Addition of High-Dose Methotrexate to Initial Chemotherapy Improved Treatment Outcome of Patients with Newly Diagnosed Intravascular Large B-Cell Lymphoma: A Multicenter, Retrospective Study

[Introduction] Intravascular large B-cell lymphoma (IVLBCL) is a rare subtype of diffuse large B-cell lymphoma characterized by selective growth of lymphoma cells in the lumina of small vessels. Although the clinical outcomes of IVLBCL before rituximab era were dismal, a retrospective analysis published in 2008 showed improved outcomes for patients treated with rituximab-containing chemotherapy (R-chemo). Furthermore, a recent multicenter, single-arm, phase II trial conducted in Japan (PRIMEUR-IVL study) supports the usage of rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone combined with high-dose methotrexate (HD-MTX) and intrathecal chemotherapy (IT), with a 2-year Overall survival (OS) of 92% and 2-year progression-free survival (PFS) of 76% in a selected population with newly diagnosed IVLBCL. However, this trial did not include a control arm, making it difficult to evaluate whether the addition of HD-MTX improves the treatment outcome. Thus, with the largest cohort (we already reported at ASH 2022), we retrospectively evaluated the efficacy of the HD-MTX in real-world settings. [Methods] Patients with histopathologically proven newly diagnosed IVLBCL according to the 2008 World Health Organization criteria between January 2010 through February 2022 from hospitals participating in the North Japan Hematology Study Group were included. Survival analysis was limited to patients with serum creatinine < 2.0 mg/dL and aged 20-79 years, following the eligibility criteria of the PRIMEUR-IVL study. PFS was defined as the time from the start of treatment to the first of progression, relapse, or death from any cause. Patients undergoing upfront autologous stem-cell transplantation (auto-SCT) were censored at the time of transplantation. [Results] A total of 110 IVLBCL cases were identified. Eighty-six patients with serum creatinine < 2.0 mg/dL, aged 20-79 years, received chemotherapy. Eighty-five of 86 patients (98.8%) received R-chemo. Thirty-six of 86 patients (41.9%) received HD-MTX during the initial therapy (w HD-MTX group), and 50 patients (58.1%) did not (w/o HD-MTX group). Fifty-six patients (65.1%) received IT. Six patients (7.0%) received upfront auto-SCT. Complete response (CR), no change (NC), and primary refractory disease were noted after initial therapy by 62 (72.1%), 11 (12.8%), and 11 (12.8%) patients, respectively. The disease progression after achieving NC was noted in 3 patients (3.5%). Fourteen patients (16.3%) experienced a relapse after achieving CR. Eight of 28 recurrences (progressions or relapses) were neurolymphomatosis forms, and 7 were central nervous system (CNS) recurrences. Twenty-five patients (29.1%) died, and 21 were due to disease progression. Compared clinical characteristics of the w HD-MTX group with the w/o HD-MTX group, the proportion of patients older than 60 years, male sex, poor performance status (ECOG PS > 1), elevated serum LDH, Ann Arbor stage III-IV and 2 or more extra-nodal lesions were not significantly different. The number of patients who received IT was significantly higher in the w HD-MTX group (77.8% vs. 56.0%, P = 0.042). Median follow-up duration for censored cases was 47.1 months (range, 7.4-130.7 months) in w HD-MTX group and 33.0 months (range, 1.78-140.5 months) in w/o HD-MTX group. Two-year PFS and OS were 73.1% (95% CI, 54.5-85.0) and 85.0% (95% CI, 67.5-93.5), respectively, in the w HD-MTX group and 54.7% (95% CI, 38.6-68.3) and 69.2% (95% CI, 53.2-80.6), respectively, in the w/o HD-MTX group (log-rank test, P = 0.016 and P = 0.005, respectively; Fig. a, b). The w HD-MTX group and the w/o HD-MTX group showed no significant difference in the cumulative incidence of CNS recurrence at 2 years (8.7%; 95% CI, 2.2-21.0 vs. 6.6%; 95% CI, 1.7-16.5, Gray test, P = 0.98). In univariate analysis, male gender, the addition of IT, and the addition of HD-MTX were significantly associated with PFS and OS ( Table). Multivariate analysis demonstrated that the addition of HD-MTX was independently associated with both PFS and OS. No HD-MTX-related deaths occurred in the w HD-MTX group. Adverse events related to HD-MTX were observed in 24 of 36 patients (66.7%), with grade 3 or 4 non-hematological adverse events in 3 patients (8.3%). [Conclusion] In conclusion, this largest retrospective study showed that the addition of HD-MTX to initial chemotherapy improved the treatment outcome of patients with newly diagnosed IVLBCL.

Significance of the Rhoa G17V Mutation Detected By Ddpcr in Diagnostic and Monitor of Angioimmunoblastic T-Cell Lymphoma

Introduction Angioimmunoblastic T-cell lymphoma (AITL) is a subtype of peripheral T-cell lymphoma (PTCL) that originates from T follicular helper cells (TFH). RHOA G17V mutation is the most common hotspot locus which could be detected in 50%-70% of cases, showing its potential value for the diagnosis and clinical monitor of this disease. Methods RHOA G17V mutation were detected by Droplet digital PCR (ddPCR) in available samples from PTCL patients, at baseline and before every cycle. Response assessments were done by PET/CT and evaluated according to Lugano criteria after 3 cycles and end of first line chemotherapy(EOT), or at suspicious of disease progression. All data analyses were performed using SPSS 20.0 software (SPSS, Inc.) and GraphPad Prism 9.0 software (GraphPad software). p-Value < 0.05 was considered statistically significant. Results 30 patients with PTCL were included in our center from 2021-01-01 to 2023-07-01,21 were confirmed as AITL and 9 were PTCL-NOS by pathologist review. In whole cohort, RHOA G17V mutation could be detected in 46.7%(14/30) of all patients, also was positive in 61.9%(13/21) and negative in 38.1% (9/21) of patients with AITL. The sensitivity and specificity of RHOA G17V mutation in AITL by ddPCR is 61.9% and 88.9%, with a positive predictive value of 92.9%, and a negative predictive value of 50%. Hyperglobulinemia, positive direct Coombs test, elevated LDH, elevated β2-MG were founded in 76.9%(10/13),61.5%(8/13) ,61.5%(8/13) and 76.9% (10/13) of AITL patients with RHOA G17V mutation, which were significantly higher than those without RHOA G17V mutation(P=0.002,0.019,0.019,0.026). Furthermore, all of the of RHOA G17V mutated AITL patients were in clinical stage III or IV(100%, 13/13), 76.9%(10/13) of them with detectable whole-blood EBV-DNA(≥500 copies/mL) and all have three or more TFH markers(100%,13/13). We next evaluated the baseline and dynamical changes in RHOA G17V VAF-positive patients with AITL. Pretreatment VAF was significantly lower for patients who achieved complete remission or partial remission at EOT compared with that of patients with progressive disease or stable disease (mean VAF, 20.75% vs. 4.31%, p = 0.0028). (Figure 1). In addition, the median PFS in AITL patients with and without RHOA G17V mutation was 9.157 months and 15.154 months respectively(P=0.32).Finally, in 10 AITL patients with dynamic results of RHOA G17V mutation (Figure 2) , a good correlation was found in between dynamic changes of VAF of RHOA G17V mutation and response assessment by PET/CT, rerise of RHOA G17V mutation VAF could be detected prior to clinical progression in two patients，showing for the its protentional value for disease monitor. Conclusions Our study first reported the diagnostic value of single hotspot detection of G17V RHOA mutation by ddPCR in PTCL. Monitoring of G17V RHOA mutation in AITL has predictive value of assess tumor burden and response, also can complement the longitudinal supervise of disease.

Sgr-1505 Is a Potent MALT1 Protease Inhibitor with a Potential Best-in-Class Profile

Background: MALT1 (Mucosa-associated lymphoid tissue lymphoma translocation protein 1) is a component of the MALT1-BCL10-CARD11 complex downstream from the Bruton Tyrosine Kinase (BTK) on the B-cell receptor signaling pathway. MALT1 is a key mediator of nuclear factor kappa B (NF-κB) signaling, which is the main driver of a subset of B-cell lymphomas. MALT1 is considered a potential therapeutic target for several subtypes of non-Hodgkin B-cell lymphomas and chronic lymphocytic leukemia (CLL), including tumors with acquired BTK inhibitor (BTKi) resistance. Constitutive activation of the NF-κB is a molecular hallmark of activated B cell-like diffuse large B cell lymphoma (ABC-DLBCL), and MALT1 may have utility as a treatment option for ABC-DLBCL. Previously, we described the discovery of novel MALT1 inhibitors with anti-proliferative effects in non-Hodgkin B-cell lymphoma cells and the strong anti-tumor activity of our MALT1 inhibitors across multiple tumor models as well as combination potential with agents including standard-of-care (ref 1, 2). SGR-1505 is an oral potent small molecule allosteric inhibitor of MALT1 that inhibits MALT1 enzymatic activity and demonstrates anti-proliferative activity in ABC-DLBCL cell lines, both BTKi-sensitive (OCI-LY10) and BTKi-resistant (OCI-LY3). When administered as a single agent and in combination with the approved Bruton's tyrosine kinase (BTK) inhibitor, ibrutinib, SGR-1505 demonstrated tumorostatic and regressive antitumor activity in ABC-DLBCL cell line-derived xenograft and patient-derived xenograft models. These data suggest that SGR-1505-mediated MALT1 inhibition has therapeutic potential for patients with selected B-cell lymphomas. Here we further characterized SGR-1505, in a series of in vitro and ex vivo assays, as well as RNA-seq analysis to examine changes in gene expression from in vivo tumor samples. We also compared SGR-1505 with a competitor Phase I candidate, JNJ-67856633 (JNJ-6633) (ref 3, 4). Results: SGR1505 potency and downstream effects were evaluated in a series of biochemical and cell based assays. SGR-1505 showed excellent potency in the biochemical assay and strong anti-proliferative effects on ABC-DLBCL cells. SGR-1505 was more potent than JNJ-6633 in all assays tested (Table 1). These results are also consistent with the result from a human primary T-cell based assay, where SGR-1505 showed at least ten-fold better potency than JNJ-6633. RNA-seq analysis was conducted to examine changes in gene expression from in vivo tumor samples. Greater modulation of BIOCARTA NF-kB pathway genes was seen with SGR-1505 compared to JNJ-6633, as measured by mean absolute change in gene expression. At 6 hr and later timepoints, we also observed a trend of increases in genes related to cell cycle pathways, such as cell cycle, DNA damage, and apoptosis. SGR-1505 is being evaluated in the SGR-1505-102 phase 1 study, which is an ongoing first-in-human, single center, dose escalation study to evaluate the safety, tolerability, PK and PD of SGR-1505 tablets in healthy participants (ACTRN12623000358640p). Preliminary data showed changes in target engagement markers at concentrations predicted by the in vitro and ex vivo assays, consistent with MALT1 protease inhibition. Conclusions: SGR-1505, a MALT1 protease small molecule inhibitor, consistently demonstrated better potency in in vitro and ex vivo assays when compared to the clinical-stage JNJ-6633 compound and greater effects on NF-kB pathway gene expression in in vivo tumor samples based on RNA-seq analysis. Changes in biological pathways mediated by MALT1 were also observed at relevant doses in the ongoing SGR-1505 healthy volunteer study. Currently, a phase 1 clinical trial in patients with mature B cell neoplasms is also ongoing (NCT05544019). The data presented suggests SGR-1505 has a potential best-in-class profile and supports advancing the ongoing clinical development of SGR-1505.

B-Cell Maturation Antigen (BCMA) Expression and Clinical Features of Plasmablastic Lymphoma (PBL)

Introduction: Plasmablastic lymphoma (PBL) is a rare and aggressive subtype of large B-cell lymphoma with plasmacytic differentiation. Although limited-stage (LS) PBL has a favorable outcome, extensive-stage (ES) PBL has a poor prognosis, with a median survival of 12-18 months. Patients with relapsed/refractory (r/r) PBL have limited treatment options and most die from the disease. B cell maturation antigen (BCMA) - directed cellular and immunotherapies are highly effective in MM. The data on BCMA expression in PBL is limited. Literature review identified one report including 7 PBL cases all of which expressed BCMA. We studied all patients with a diagnosis of PBL who presented to Moffitt Cancer Center in Florida, USA from Jan. 2006 to Apr. 2023, and retrospectively performed BCMA immunohistochemistry (IHC) staining on the available archived FFPE biopsy samples. Methods: Progression-free survival (PFS) was calculated as time from disease progression or last follow up to treatment start date. Overall survival (OS) was calculated as time from death or last follow up to date of PBL diagnosis. Association of BCMA expression with PFS or OS was evaluated using logrank test, with continuous variables converted to categorical by classifying as above or below median. All analyses were done using SAS 9.2. Results: A total of 32 PBL patients were identified. The median age was 59 years (range 31-83 years); 21 (65.6%) had stage III/IV (ES); 9 patients (28.1%) were HIV positive; and 57.1% of evaluated cases were EBV positive by EBER. Treatment data was available for 30 patients. The most common frontline therapies were EPOCH and CHOP with or without rituximab; four patients received bortezomib combined with EPOCH; 7 patients (23.3%) received autoSCT in 1 st remission (Table 1). Median follow-up was 77.6 months calculated using the reverse Kaplan-Meier method. Consistent with previous reports, patients with ES PBL had worse outcome than those with LS PBL, with 3-year OS rates of 24% and 100%, respectively, p=0.01 (Table 1). Among the 20 patients with ES PBL and known treatment responses, 11 did not achieve CR after frontline therapy. Ten of these 11 patients died due to disease progression, 9 within 2 years and 1 within 3 years. Two patients received CD19 CAR-T after multiple lines of therapy. Both died within 30 days, one from disease progression and the other from multiple treatment complications. Out of the 18 cases with tissue available for IHC study, 17 (94.4%) had positive BCMA expression (Figure 1). The median percentage of BCMA+ cells was 75% (Table 1). Eleven (61.1%) cases had intermediate to strong BCMA staining. Neither BCMA+ cell percentage nor BCMA expression level was associated with disease stage, response rate, PFS, or OS (p>0.10 for all tests). Discussion: In our study the majority of our PBL cases tested positive for BCMA, and the percentage of BCMA+ cells seemed comparable to MM cases.To our knowledge, this is the largest and the first report that systemically evaluated BCMA expression in PBL. Our results provide evidence to explore BCMA as a potential target in PBL. Currently two anti-BCMA CAR-T products and an anti-BCMA/CD3 bispecific T-cell engager have been approved for r/r MM. A BCMA-targeting antibody-drug conjugate (ADC) Belantamab mafodotin-blmf was initially granted accelerated approval by FDA for r/r MM but was later voluntarily withdrawn from the market. Given the expression of BCMA in PBL and the lack of effective treatment of r/r PBL, these patients could be considered in trials evaluating the BCMA-targeting therapies. In fact, in a case report recently published, one patient with refractory PBL achieved CR after one infusion of BCMA CAR-T and remained in CR after 14 months. Ten of our 11 ES patients who did not achieve CR after frontline chemotherapy died from the disease, emphasizing the importance of clinical trials for this condition. We did not find an association of BCMA expression with clinical outcomes as oppose of MM, in which higher BCMA expression was associated with shorter PFS and OS. The lack of association in our study may be due to the small sample size, or, it may reflect a difference in biological role of BCMA in PBL from MM. Our results will need to be corroborated with other series to confirm our findings. Translational studies need to evaluate the dynamics of BCMA protein expression on PBL cell membrane and the activity of BCMA-targeting agents in vitro and in animal models of PBL.

A Retrospective Analysis of the Trends in Mantle Cell Lymphomas in the United States

Introduction: Mantle Cell Lymphoma (MCL) refers to the malignant B lymphocytes arising from the outer (mantle) zone of the lymphoid follicle. This rare and aggressive subtype of Non-Hodgkin Lymphoma, which accounts for ~5 percent of all NHL cases. It is associated with t(11:14) that leads to over-expression of cyclin D1, resulting in tumor cell proliferation via cell cycle dys-regulation, chromosomal instability, and epigenetic regulation. The aim of this study is to understand the epidemiology and survival predictors of MCL. Methods: The data was collected from Surveillance, Epidemiology and End Result database Research Plus Data, 17 Registries, Nov 2022 Sub (2000-2020). We extracted Mantle Cell Lymphoma cases diagnosed after 20 years of age, with Lymphoid neoplasm recode 2(a)2.1.3. The analysis was stratified based on age, sex, racial incidence rates, & survival curves based were compared, using the Log-rank test (GraphPad Prism). Results: A total of 14166 cases of MCL were found between 2000 to 2020. Out of these, ~70.73% cases were males, and ~29.27% were females. The median age at the time of diagnosis was 69 years. Of the affected population, ~80.60% were Caucasians, ~3.92% were African-Americans, ~4.10% were Asians/Pacific Islanders, only ~0.50% were American Indians/Alaskan Natives, and ~10.32% were Hispanics. The incidence per 1,000,000, as of 2020, was 10.83 for the general population, 13.00 for Caucasians, 5.01 for African-Americans, 13.71 for American Indians/Alaskan Natives, 3.28 for Asians/Pacific Islanders, and 9.43 for Hispanics. Survival curves were not significant when compared based on the race of the patients. However, survival curves showed statistical significance when compared based on gender, with median of survival (mOS) for males was 50 months, and for females mOS was 56 months (p-value 0.0.008, Hazard Ratio 1.084 [Confidence Interval 1.035 to 1.136], using Log-rank test. Conclusions: Mantle Cell Lymphoma has a strong predilection for males. It is more commonly diagnosed in the late 60s, median age being 69. Unequal racial distribution was noted, with caucasians (~80%) comprising most of the patient population, and the least commonly encountered were American Indians/Alaskan Natives(~0.50%). However, when incidence rates were calculated per 1,000,000 population in 2020, it was found that the incidence in American Indians/Alaskan Natives (13.71), is drastically higher than the general population(10.83) vs. incidence in Asians/Pacific Islanders(3.28) is significantly lower than the other races. Although race played no role in prognosis, females had better survival rates than males. This retrospective study was done to aid in better understanding of this curable malignancy, despite its rarity, aggressivity and the complexity in treatment.

Gp350-Targeted CAR-T Therapy in EBV-Positive NK/T-Cell Lymphoma: Pre-Clinical Development of gp350CAR-T

Introduction: Epstein-Barr virus (EBV) positive NK/T cell lymphoma is a subtype of non-Hodgkin's lymphoma strongly associated with EBV infection. EBV infection has been reported in 85-100% of cases. It has been suggested to be central in pathogenesis. The incidence of EBV+ NK/T cell lymphoma is increasing worldwide, particularly in Asia and Latin America, and it has a poor prognosis with few effective treatment options. Therefore, novel approaches for treating EBV-associated NK/T cell lymphoma are urgently needed. Developing chimeric antigen receptor (CAR)-T cells therapy targeting EBV specific protein in the context of this EBV-positive aggressive lymphoma will provide a novel therapeutic strategy for patients with limited treatment options. Targeting EBV lytic protein for control EBV in vivo replication and tumorigenesis have been explored lately. The gp350 protein is a major glycoprotein on the surface of EBV during its lytic phase, after fusion between virus and host cell membrane, gp350 is left on the host cell surface. The distinct surface distribution pattern of gp350 in both freshly infected host cells and the lytic phase host cells renders it an attractive target for immunotherapy. Method and Result: We developed EBV specific CAR-T cells targeting gp350. We utilized single-chain variable fragments (scFvs) derived from four novel, gp350-binding, neutralizing monoclonal antibodies (mAbs) (12C10, 7D11, 6A12, 7A8) to generate the CAR constructs. We demonstrated that these scFvs, when fused to a second-generation CAR backbone consisting of 4-1BB and CD3ζ signal domains, are efficiently expressed on the surface of transduced T cells. These gp350 CAR-T cells exhibit specific activation and cytotoxic effects in vitro. Of note, the clone 6A12 scFv of CAR displayed the most potent cytotoxicity effects in gp350 positive cancer coculture toxicity assays. To optimize the CAR structure further, we designed various linker and transmembrane domains based on the clone 6A12 scFv, including CD8 linker, IgG4 hinge, IgG1 Fc linker, and CD28 linker and transmembrane domains. Our cytotoxicity assay screening indicated that the CD8 linker and transmembrane domain resulted in the most advanced cytotoxicity and target specificity (Figure A, B). To assess gp350 CAR-T efficacy in vivo, we established a T-cell leukaemia animal model in NOD immune-deficient mice through intravenous injection of Jurkat-gp350-luc cells. On post xenograft day 7, the Jurkat-gp350-luc xenografted mice were separated into three groups and each group with 5 mice (except PBS group with 2 mice). CAR-T and T cell were infused by tail vein injection with mock T 2x10^6/mouse, 6A12CAR-T 2x10^6/mouse and PBS control. The tumor growth in mice was monitored by in vivo luminescence with IVIS imaging system. Upon engraftment, Jurkat-gp350-luc cells established disseminated leukaemia expanding preferentially in the spine, femur, head, and pelvis, with few cells in peripheral blood. Mice receiving control mock T cells or without T cell PBS control developed rapid disease progression and were euthanized by day 35 after Jurkat-gp350-luc engraftment. In contrast, mice receiving gp350 CART cells were significantly protected from rapid progression (Figure C, D). Conclusion: In pre-clinical development, we designed, constructed, and screened gp350 CAR-T cells to demonstrate its efficacy in vitro and in vivo against and kill gp350 positive leukaemia cells and prevent formation and development leukaemia in xenograft mice model.

Skeletal Muscle Index, As a Measure of Muscle Mass, Is a Significant Prognostic Factor for Newly Diagnosed Diffuse Large B-Cell Primary CNS Lymphoma Patients

Background: Primary cerebral lymphoma (PCNSL) is a rare subtype of diffuse large B-cell lymphoma (DLBCL) with a particularly poor outcome compared to systemic DLBCL. Several prognostic scores have been developed for PCNSL. These include the International Extranodal Lymphoma Study Group (IELSG) score with five prognostic factors (patient age, serum lactate dehydrogenase [LDH] level, Eastern Cooperative Oncology Group performance status [PS], deep brain involvement and cerebrospinal fluid [CSF] protein level), and the Memorial Sloan-Kettering Cancer Center (MSKCC) score, which is based on age and the Karnofsky Performance Score (KPS). However, the reproducibility of these two scoring systems is low, and the IESLG score requires CSF protein and LDH levels evaluation, which are not often available. None of these scores incorporate data on nutritional status, in particular albumin, which has been shown to be an important prognostic factor in systemic DLBCL. In addition, a recent study demonstrated that the muscle density and mass determined by imaging segmentation, were strong prognostic factors for newly diagnosed systemic DLBCL patients (Jullien et al. Cancers 2021). Our aim was to determine whether these imaging data were also predictive factors for outcome in newly diagnosed diffuse large B-cell PCNSL patients. Methods: For each patient included in the study, muscle mass and density were estimated using skeletal muscle index (SMI) and mean skeletal muscle radiation attenuation (SMRA), respectively. SMI and SMRA were computed at L3 level using the whole-body scan (WBS) performed at the diagnosis of PCNSL, by the mean of an automated segmenting algorithm. Muscle characteristics were then classified as normal or low using already validated cut-off according to patients' age and body mass index (Westenberg et al. Sci Rep 2023). Patients' outcomes were then compared based on their muscle quality, albumin level at diagnosis and other clinical variables commonly included in PCNSL prognostic scores. Results: Between 2015 and 2022, 98 consecutive diffuse large B-cell PCNSL patients were newly diagnosed at Hematology Department of Hospital Lyon Sud, France. Among them, 77 had WBS at diagnosis with available data for this study. The median age was 69 years (range 24-87) and 22 patients (29%) presented an altered ECOG PS (PS 3-4 score). All patients were treated with first-line high-dose methotrexate-based chemotherapy in combination with rituximab. SMI was normal in 64 patients (83%) and 17 patients (17%) had low SMI. Patients with low SMI had more frequently an altered PS (p=0.07) and had lower albumin level (mean 36.7 g/L vs 32.0 g/L, p=0.007). SMRA was normal in 30 patients (39%) and 47 patients (61%) had low SMRA. Patients with low SMRA were older (60 vs 70 years old, p=0.001). In univariate analysis, patients with low SMI had worse outcome with significantly shorter overall survival (p=0.002, median OS, 21.4 months vs not reached) and a trend towards shorter event-free survival (p=0.055, median EFS, 11.9 months vs 42.3 months, Figure 1). No significant prognostic difference was seen for SMRA for EFS or OS. The multivariate analysis showed that SMI (Hazard ratio [HR]=3.33, 95% confidence interval [95%CI]= 1.21-9.20, p=0.02) and age (HR =1.86, 95%CI =1.15-3.0, p=0.012) were strongly associated with OS but not tumor localization (HR =1.46, 95%CI =0.60-3.55, p=0.4), PS (HR = 1.54, 95%CI =0.65-3.65, p=0.32) and albumin level (HR =1.05, 95%CI =0.47-2.32, p=0.91). Age was significantly associated with EFS (HR=1.4, p = 0.04) with a more limited association of SMI with EFS (HR=2.03, p=0.095). In exploratory subgroup analyses, we showed that SMI still influenced OS in patients with PS 4 (10 months vs not reached, p= 0.002), suggesting that SMI may be a more appropriate prognostic factor than PS, especially for patients with motor deficit for whom PS is difficult to estimate. Conclusions: This retrospective analysis of newly diagnosed PCNSL patients showed a significant association between decreased muscle mass, measured by SMI and overall survival, after controlling for other prognostic variables. These findings warrant confirmative analyses to explore the relationship between muscle mass/density and diffuse large B-cell PCNSL patient's outcome and integrate SMI in PCNSL prognostic scores.

Development of Syngeneic Murine Cell Lines of Germinal Center-Derived B-Cell Lymphomas

Background. Germinal center (GC)-derived B-cell lymphomas are clinically and biologically heterogeneous. Next generation sequencing has enabled identification of genetic aberrations involved in lymphoma pathogenesis, which may provide prognostic predictions and potential therapeutic targets. However, the mechanisms driving pathogenesis are still not fully understood, especially in the context of an intact tumor microenvironment, in part because there are no available syngeneic models of lymphoma faithfully representing the pathological features of human disease. Therefore, there is a critical need for lymphoma models which can be studied in immunocompetent mice. Methods. We established eight murine cell lines derived from spontaneous B-cell lymphomas with GC origin arising in genetically engineered mouse models (GEMM). These cell lines were developed by passing an original tumor from a GEMM through several passages of Rag1-/- and wild type mice, which enabled selection of more fit/aggressive clones that grow in vitro. We also tested multiple culture conditions and characterized the lines via flow cytometry, VDJ and targeted sequencing, karyotyping, and evaluation of tumor development and its microenvironment in vivo. Results. This resource describes eight cell lines driven by recurrent genetic mutations found in diffuse large B-cell lymphoma and follicular lymphoma patients. The first cell line is defined by (1) BCL2 overexpression (hereafter B2). Four cell lines couple BCL2 overexpression with epigenetic dysregulation, defined by (2) BCL2 and gain-of-function (GOF) mutation of EZH2 Y641F (hereafter EZB), (3) EZB and MYC overexpression (hereafter EBM), (4) BCL2 with knockout of KMT2D (hereafter KB), and (5) BCL2 with knockout of SETD2 (hereafter S2B). Finally, three cell lines are defined by mutations to the Toll-like and B-cell receptors pathways, defined by (6) BCL2 and GOF mutations in Myd88 L252P and CD79b Y195H (hereafter MBC79), (7) BCL2, Myd88 L252P and GOF mutation in Card11 L251P (hereafter MBC11), and (8) BCL2 and Card11 L251P (hereafter BC11). Doubling time of these lines ranges from 30-72 hours, with EZB and EBM on the fast end and S2B on the slow end. By flow cytometry, we show that B2, MBC79, and MBC11 lose B-cell surface markers and are very plasmacytic (>95% B220- CD19- CD138+). In contrast, the EZB, EBM, KB, BC11, and S2B are mostly characterized by GC B-cell markers (B220+ CD19+ CD138- FAS+ CD38- GL7+). By VDJ sequencing, we found that EZB, BC11, and S2B are very monoclonal, with one rearrangement arising from the original tumor and taking over to represent >95% of clones. In contrast, the MCB11 and MBC79 lines are very polyclonal, with the top 10 rearrangements being equally represented, and tending to shift between passages. Thus far, S2B and EZB have been shown to grow in immunocompetent mice, representing novel syngeneic lymphoma models. While mice injected with S2B can survive for up to 30 days, mice injected with EZB die significantly earlier. We established two EZB lines from early (P1) and late (P6) passages of a tumor arising from the same original mouse. Notably, we show that mice injected with P1 survive 15-20 days, whereas mice injected with P6 survive 10-15 days. Although both P1 and P6 grow at similar rates in vitro, P1 develops high grade follicular lymphomas in C57BL6 recipients, whereas P6 develops DLBCL, suggesting additional passaging drives selection for more aggressive disease. Imaging of the tumors reveals a lack of follicular pattern. Notably, P6 tumors display less infiltration of CD4 and CD8 T-cells and low abundance or absence of FDC meshwork, as compared to P1. Imaging of mice engrafted with luciferase transduced P1 and P6 shows dissemination into spleen, lymph nodes, liver, and kidney, with more advanced disease in P6 injected mice. Conclusion. While conventional preclinical tumor mouse models are often used for drug sensitivity and treatment prediction studies, they are time-consuming and expensive. These cell lines serve as a preclinical tool to test novel therapeutic strategies and develop a deeper understanding of the molecular mechanisms driving lymphomagenesis, therapeutic response, and resistance in genetically defined subtypes of GC-derived B-cell lymphomas. Most importantly, this resource meets a critical need in the field for syngeneic models of lymphoma to study disease progression and precision therapy in immunocompetent mice.

Assessment of the Expression of Genes Related to Epigenetic and Chromatin Modifications in Diffuse Large B-Cell Lymphoma Patients Resistant to R-CHOP

Introduction Diffuse large B-cell lymphoma (DLBCL) is the most common subtype of non-Hodgkin lymphoma. The mainstay of frontline therapy remains R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone) or R-CHOP-like immunochemotherapy. Patients' responses to R-CHOP therapy vary depending on the stage and/or molecular subtypes of DLBCL. Approximately 40% of advanced-stage DLBCL patients suffer from a refractory or relapsed disease[1]. The outcome for patients with early relapses after rituximab-containing first-line therapy remains poor[2]. DLBCL poses a marked degree of genetic heterogeneity. Here, we compare the expression of genes related to epigenetics and chromatin modifications in DLBCL patients resistant and non-resistant to R-CHOP therapy. Objective The aim of this study is to assess the differences in the expression of genes related to epigenetics and chromatin modification in DLBCL patients that could lead to chemoresistance and failure of R-CHOP treatment. Method The gene expression profile (GEP) was obtained from Gene Expression Omnibus (GEO) database (Accession number: GSE173263) submitted by Dlouhy et al[3]. The GEP was analyzed in DLBCL cases, including 10 early failure cases (defined as refractory to induction treatment or early relapsing (<12 months from diagnosis)) and 29 responding patients, to identify features associated to primary chemoresistance. The comparison was done using the list of genes proposed by Bakhshi, T. et. al[4] , where he selected the genes that were identified to potentially cause epigenetic and chromatin modifications in DLCBL. All the comparisons were done using a T-test. Results There were significant differences in the gene expression related to epigenetics and chromatin modifications between DLBCL patients in the early failure arm versus the remission arm. Patients who had early failure to R-CHOP tended to have higher expression of these genes: SMARCA4 (p=0.010), SETD1B (p=0.018), SETD2 (p=0.024), EP300 (p=0.012), MLL3 (p=0.049), INO80 (p=0.001), CHD8 (p=0.007), NCOR1 (p=0.020), ARID1B (p=0.034), and SETD5 (p=0.007). Compared to the patients who were in remission after R-CHOP therapy, these patients had significantly higher expression of HIST1H1E (p=0.007). Conclusion Gene expression related to epigenetics and chromatin modifications significantly impacts the prognosis of DLBCL patients treated with R-CHOP. Differences in gene expression may lead to chemoresistance, and higher expression levels are associated with a worse prognosis. This study sheds light on the importance of chromatin and epigenetic modifications in DLBCL progression, guiding the development of future therapies.

Phase 2 Search Study：XPO1 Inhibitor (ATG-010) Monotherapy in Heavily Pretreated Chinese Patients with Relapsed or Refractory Diffuse Large B-Cell Lymphoma

Background Relapsed or refractory diffuse large B-cell lymphoma (R/R DLBCL) is an aggressive and most globally prevalent subtype of non-Hodgkin's lymphoma with a dismal prognosis. Selinexor (ATG-010) is an oral selective inhibitor of nuclear export, which blocks exportin1 (XPO1). The US FDA granted accelerated approval to selinexor for the treatment of adult patients (pts) with DLBCL, not otherwise specified, including DLBCL arising from follicular lymphoma, after at least 2 lines of systemic therapy based on the Phase 2b SADAL study (NCT02227251). SEARCH is a single arm, Phase 2, registrational bridging study to assess efficacy and safety of selinexor in Chinese pts with R/R DLBCL. Method SEARCH was designed to evaluate safety and efficacy of selinexor (60mg Days 1 and 3 of Weeks 1 to 4 of each 4-week cycle) in R/R DLBCL pts in China with 2-5 prior lines of systemic therapy. The primary endpoint was overall response rate (ORR) assessed by an Independent Review Committee (IRC). The study was registered at ClinicalTrials.gov (NCT03992339), with the primary analysis results presented here. Results As of 31 st May 2023 (6 months post last pt dosed), 5 (8.3%) of the 60 treated pts remained on treatment. Median follow-up was 27.7 months (mo) (range: 6.0-37.7). Median age was 58.5 years (20.0%≥70yrs). Median duration from initial DLBCL diagnosis was 1.8 years (range: 0.5-11.2). A total of 7 pts (11.7%) had DLBCL arising from indolent lymphoma, 4 (6.7%) had creatinine clearance <60ml/min and 27 (45.0%)/33 (55.0%) had GCB/non-GCB subtype, respectively. Median number of prior regimens was 3 (range: 2-5); 5 pts (8.3%) had received prior ASCT. Patients had received the following novel treatments, which were not previously received by patients in SADAL: 10 (16.7%) chidamide, 8 (13.3%) BTK inhibitor, 6 (10.0%) PD-1/PD-L1 antibodies, 3 (5.0%) polatuzumab, 1 (1.7%) PI3K inhibitor, and 4 pts (6.7%) had undergone CAR-T cell therapy. Thirty-two pts (53.3%) were with primary refractory DLBCL and 54 pts (90.0%) were refractory to the last systemic therapy for DLBCL. ORR was 21.7% (95% CI: 12.1, 34.2) and CR rate was 16.7%. Median duration of response (DOR) was 7.6 mo, median progression free survival (PFS) was 1.9 mo, and median overall survival (OS) was 8.5 mo. Efficacy was evident in pts who had poor prognostic factors, including elderly pts (≥70yrs) with ORR 16.7%, pts with renal dysfunction with ORR 25.0%, primary refractory pts with ORR 18.8% and pts refractory to their last systemic therapy with ORR 16.7%. And pts with De novo/transformed DLBCL with ORR 17.0%/57.1%, pts with GCB/non-GCB DLBCL with ORR 25.9%/18.2%, pts with/without prior ASCT with ORR 40.0%/20.0%, pts with 2/more than 2 previous regimens with ORR 25.9%/18.2%. One pt (1/4) with prior CAR-T achieved PR assessed by investigators. All pts experienced at least one treatment-emergent adverse event (TEAE), 47 (78.3%) with at least one Grade 3/4 TEAE, and 24 (40.0%) with at least one serious TEAE. The most common non-hematologic TEAE of any grade (≥20%) included decreased appetite (61.7%), nausea (58.3%), weight loss (38.3%), vomiting (33.3%), diarrhea (31.7%), asthenia (30.0%), hyponatremia (26.7%), constipation (25.0%) and AST increased (20.0%). The most common grade≥3 non-hematologic TEAE (≥2%) were decreased appetite (6.7%), diarrhea (5.0%), vomiting (5.0%), hyponatremia (3.3%), asthenia (3.3%), pneumonia (3.3%), dyspnea (3.3%) and COVID-19 pneumonia (3.3%). The most common hematologic TEAE of any grade (≥20%) were thrombocytopenia (83.3%), leukopenia (81.7%), neutropenia (80.0%), anemia (75.0%) and lymphopenia (30.0%). The most common grade≥3 hematologic TEAE (≥10%) were thrombocytopenia (41.7%), leukopenia (40.0%), neutropenia (36.7%), anemia (23.3%) and lymphopenia (16.7%). The most common AEs were generally manageable by dose modification and supportive care. Conclusions R/R DLBCL remains a high unmet medical need, especially in pts who are ineligible/frail to transplantation. The SEARCH study demonstrates clinically meaningful ORR in Chinese R/R DLBCL pts treated with selinexor monotherapy, consistent with the global study. Adverse events were generally manageable with appropriate supportive care and dose modification. These data are generally consistent with the SADAL study and supports the use of selinexor as an oral, chemotherapy-free treatment option for R/R DLBCL patients in China.

A Phase 1, Open-Label, Multicenter, Dose-Escalation Study of Sgr-1505 As Monotherapy in Subjects with Mature B-Cell Malignancies

Background and Significance: MALT1 (Mucosa-associated lymphoid tissue lymphoma translocation protein 1) is a component of the MALT1-BCL10-CARD11 complex downstream from the Bruton Tyrosine Kinase (BTK) on the B-cell receptor signaling pathway. MALT1 is a key mediator of nuclear factor kappa B (NF-κB) signaling, which is the main driver of a subset of B-cell lymphomas. MALT1 is considered a potential therapeutic target for several subtypes of non-Hodgkin B-cell lymphomas and chronic lymphocytic leukemia (CLL), including tumors with acquired BTK inhibitor (BTKi) resistance. Constitutive activation of NF-κB is a molecular hallmark of activated B cell-like diffuse large B cell lymphoma (ABC-DLBCL), and MALT1 may have utility as a treatment option for ABC-DLBCL. Furthermore, a MALT1 inhibitor (JNJ-67856633) showed efficacy in mature B cell malignancies from phase 1 studies (ref 1, 2). SGR-1505 is an oral potent small molecule allosteric inhibitor of MALT1 that inhibits MALT1 enzymatic activity and demonstrates anti-proliferative activity in BTKi-sensitive (OCI-LY10) and BTKi-resistant (OCI-LY3) ABC-DLBCL cell lines. SGR-1505 administered as a single agent and in combination with the approved Bruton's tyrosine kinase (BTK) inhibitor, ibrutinib, demonstrates tumorostatic and regressive antitumor activity in ABC-DLBCL cell line-derived and patient-derived xenograft models. These data suggest that SGR-1505-mediated MALT1 inhibition may expand therapeutic options for patients with selected B-cell lymphomas, supporting further evaluation of SGR-1505 in clinical trials. Study Design and Methods: SGR-1505-101 (NCT05544019) is a phase 1, multicenter trial of SGR-1505 as monotherapy in subjects with mature B-cell malignancies (figure 1). At present, the study is open to accrual at multiple investigative sites in the US with plans to expand to Europe. The primary objective is to evaluate safety and tolerability of SGR-1505 as monotherapy and to identify the maximum tolerated dose (MTD) and/or recommended dose (RD). Secondary objectives are to evaluate the pharmacokinetic (PK) profile, food effect, drug-drug interaction, and preliminary anti-tumor activity of SGR-1505. Key inclusion criteria are: history of mature B-cell malignancy (including aggressive and indolent B-cell lymphomas, Waldenström macroglobulinemia, and CLL); measurable or detectable disease according to the applicable disease-specific classification system (Lugano, iwCLL, WWM6); Eastern Cooperative Oncology Group (ECOG) performance status of ≤ 2. Patients with indolent B-cell lymphomas or CLL must have an indication for treatment and not require immediate cytoreductive therapy. Subjects with symptomatic or active CNS involvement, and other conditions or laboratory findings placing them at increased risk to the use of an investigational drug are excluded. SGR-1505 is initially dose-escalated using an accelerated titration design in cohorts of 1-6 subjects, and at higher dose levels using a conventional 3+3 design.

Plasmablastic Lymphoma Descriptors and Clinicopathologic Determinants of Survival: Analysis of a Pooled Database

Background Plasmablastic Lymphoma (PBL) is a rare and aggressive subtype of non-Hodgkin's lymphoma. It tends to be associated with immunosuppressive clinical contexts, such as HIV infection and immunosuppressive therapies for autoimmune disorders and organ transplants. However, due to the rarity of the disease, which is poorly understood, varied treatment approaches have been implemented, and no optimal data or guidelines for managing PBL are available. Furthermore, a few small case series reported conflicting prognosticators. Therefore, we conducted this pooled database analysis to identify the prognostic factors, clinicopathological characteristics, and therapeutic strategies influencing survival in this rare disease. Methods To study the demographic characteristics, molecular and immunohistochemical signatures, therapeutic interventions, survival, and prognostic factors, we compiled a pooled database of 300 cases that fit the diagnostic criteria for PBL. Kaplan-Meier survival curves were constructed. Cox proportional hazards model and Log-rank tests were used to assess the influence of demographic and clinicopathologic factors on overall survival (OS). Results A total of 300 patients with confirmed PBL were identified. The median age was 49. There was a male preponderance with M:F of 2.7. The median duration of symptoms before diagnosis was 1 month. PBL involved the H&N (39%), Lymph nodes (LN) (33%), GI tract (31%), bone marrow (17%), bones (14%), lungs and pleura (10%), skin (9%), spleen (7%), liver (6%), CNS (6%), and testes (2%). Constitutional symptoms were reported in 35%. Stage III/IV accounted for 51% of the cohort. Sixty-two percent were immunosuppressed, 47% due to HIV. While 58% were Kappa restricted, 40% were Lambda, and 2% null. The median OS and DFS of the whole group were 25 and 15 months, respectively. The involvement of BM (p<0.0001), liver (p=0.003), lungs/pleura (p<0.0001), and upper GI tract (0.001) was associated with worse OS. Moreover, CD4<100 (p=0.006), HHV8+ (p=0.02), EBER-negative (p=0.01), LDH>500 (p=0.04), and stage>2 (p<0.0001) were also associated with worse OS. PBL involving the H&N had better OS (p=0.0001). Though CNS involvement, presence of constitutional symptoms, and MYC+ had numerically worse OS, it did not reach statistical significance. Age, sex, light chain restriction, type of immunosuppression, other organ involvement, and other IHC phenotype did not impact OS. Compared to no treatment, chemotherapy and stem cell transplant had incrementally superior median OS (2 vs. 27 vs. NR months, p<0.0001). Frontline intensive chemotherapy yielded better OS than CHOP-like and myeloma regimens in decreasing order (p<0.0001). Patients who attained CR as their best response also had a superior median OS (p<0.0001). Conclusion This study presents clinicopathologic data from the largest pooled cohort of patients with PBL. It identifies the type of organ involvement, CD4 counts, EBER and HHV8 status, LDH levels, stage, type of therapy, and quality of response to treatment as critical determinants of OS.

PI3Kδ Inhibitor Linperlisib As a ≥ 3-Line Treatment for Relapsed or Refractory Follicular Lymphoma: A Subgroup Analysis of a Phase II, Single-Arm, Open-Label Trial

Introduction Follicular lymphoma (FL) is the most common subtype of indolent non-Hodgkin lymphoma (NHL), originating in follicular central B cells, and accounts for approximately 22% of all newly diagnosed cases of NHL. Chemo-immunotherapy is the standard treatment option for FL. Unfortunately, the progression of the disease to relapsed or refractory FL (r/r FL) is still inevitable, which raised concern about subsequent effective treatments. Several δ isoform of phosphatidylinositol 3-kinase (PI3K-δ) inhibitors have ever been approved for r/r FL after ≥2 lines of prior therapies. However, most of their indications for r/r FL were withdrawal for increased risk of death and serious side effects. The latest data from the Chinese phase II clinical trial of linperlisib (Trial registration ID: NCT04370405), a novel oral PI3Kδ-selective inhibitor, in patients with r/r FL who had received at least two systemic therapies were presented. In this trial, linperlisib demonstrated compelling efficacy and was generally well-tolerated in the treatment of r/r FL patients after ≥2 prior systemic therapies. Linperlisib was approved by China National Medical Products Administration (NMPA) for adult r/r FL previously treated with at least two system therapies in November 2022. The ≥3 lines of treatment options are still unmet for the r/r FL. In this setting, this subgroup analysis of the linperlisib phase II trial aimed to evaluate outcomes of linperlisib in later-line treatment of r/r FL. Methods This study included all the patients with r/r FL who had received at least two systemic therapies previously enrolled in the open-label, single-arm, phase II trial (linperlisib, 80mg, po, q.d., in a 28-day cycle), with overall response rate (ORR) as the primary endpoint. In this subgroup analysis, the patients were divided into two groups according to the treatment lines they received: >3 prior lines of treatment and ≤3 prior lines of treatment. All of the statistical analyses were descriptive. Results A total of 84 r/r FL patients from 25 sites in China from April 2019 to September 2020 were enrolled in this trial, with a cutoff date of September 30, 2021. The ORR was 79.8%, with statistical significance in a heavily pretreated FL patient population with a median of 4 prior therapies, with a well-tolerated safety profile. A total of 43 patients received >3 prior lines of treatment, while 41 patients received ≤3 prior lines of treatment. The median age between the two groups was similar (range: 29.0 - 78.0, 52.0 years for >3 prior lines vs. 48.0 years for ≤3 prior lines). The majority of patients had Ann Arbor staging III-IV (40 for >3 prior lines vs. 34 for ≤3 prior lines). The median number of prior regimens was 4 for >3 prior lines and 3 for ≤3 prior lines. Overall, there were 67 patients achieved responses, with ORR of 83.7% (36, 95%CI:69.3, 93.2) for >3 prior lines vs. 75.6% (31, 95% CI: 59.7, 87.6) for ≤3 prior lines based on independent review committee assessment. Compared with patients who received ≤3 prior lines, patients received ≤3 prior lines achieved higher disease control rate (41[95.3] vs. 37 [90.2%]). The median DOR was 12 months (95% CI: 7.3, 15.9) for >3 prior lines vs. 13 months (95% CI: 9.2, NE). The median PFS was 11.9 months (95% CI: 9.1,19.4) for >3 prior lines vs. 13.3 months (95% CI: 8.2, NE) for ≤3 prior lines. The OS of both groups was not reached. The most common treatment-related adverse events (≥20%, TRAEs) were neutropenia (21 [48.8%] for >3 prior lines vs. 18 [43.9%] for ≤3 prior lines), leukocyte count decreased (15 [34.9%] vs. 15 [36.6%]), alanine aminotransferase increased (10 [23.3%] vs. 9 [22.0%]), lymphocyte count decreased (9 [20.9%] vs. 5 [12.2%]), hypertriglyceridemia (9 [20.9%] vs. 11 [26.8%]), and hypercholesteremia (6 [24.0%] vs. 7 [11.9%]). The most common grade ≥3 TRAEs (≥10%) were neutropenia (9 [20.9%] vs. 4 [9.8%]), pulmonary inflammation (3 [7.0%] vs. 6 [14.6%]), infectious pneumonia (2 [4.7%] vs. 5 [12.2%]). Conclusions This subgroup analysis revealed that linperlisib could achieve benefit in r/r FL patients who received at least 2 prior system therapies regardless of treatment lines. The AEs were well-tolerated. Further trials with large-scale samples were warranted.

Distinct Subtypes of Chemotherapy-Resistant Systemic ALK-Positive Anaplastic Large Cell Lymphoma Demonstrate Long-Term Complete Remissions to Imatinib

Background Platelet-derived growth factor receptor (PDGFR) is expressed in nucleophosmin-anaplastic lymphoma kinase (NPM-ALK) positive anaplastic large cell lymphomas (ALCL ALK+). Our previous preclinical research suggested that PDGFR blockade by the Abl/c-Kit/PDGFR kinase inhibitor imatinib could be an effective treatment strategy for ALCL ALK+. An indicator patient whose ALCL cells expressed PDGFR and who failed three treatment lines (including autologous stem cell transplantation) achieved complete remission (CR) with imatinib. Methods We treated 6 relapsed/refractory (r/r) ALK+ ALCL patients with imatinib, 4 of which within the prospective clinical trial, EudraCT No.: 2013-003505-26. Median follow-up was 40 months (160 weeks, range 4 - 428). Patients were characterized by whole exome sequencing, bisulfite sequencing, RNA-sequencing and immunological profiling. Whole exome sequencing data were integrated and compared to 32 additional ALK+ ALCL patients (Larose et. al., Haematologica, 2021; Creszenzo et al., Cancer Cell 2015; Mologni et al. (unpublished). Results 5-year progression-free survival (PFS) was 67%. 4 out of 6 patients achieved a CR that was maintained throughout the follow-up of 3.3 - 8.9 years. Lymphoma cells of the non-responding patients did not express PDGFRA/B as confirmed by immunohistochemistry and RNA-scope (panel figure A). Cytoplasmic co-expression of both, ALK and PDGFRA/B, in ALCL tumor cells was associated with complete response to imatinib in ALK+ ALCL patients. Methylation profiling confirmed a differentially activated PDGFR axis between responders and non-responders and identified a specific protein kinase profile that included a significant inflammatory upregulation of HGFAC, VEGFa, and TNFa in serum cytokine profiling. The transcriptional differential gene expression includes an upregulation of genes of GO:0045859 (regulation of protein kinase activity) in non-resonders. Ident pathologic variants resulting in amino-acid changes were detected in non-responders in mutated genes linked to kinase activity ( TBC1D28 E56A), protein processing ( EMC1 S323T: cosmicV64345386 and EMC1S325N: cosmicV100916421; and GOLGA8S) and cytokine signaling ( IFNL2, ZFYVE19). The imatinib-resitance profile involving mutations in EMC1 and GOLGA8S could be detected at a frequency of 6/32 (19%) in an independent reference cohort of r/r ALK+ALCL (panel figure B). Exclusive mutations in PPP1R13B linked to p53-pathway were found in all responders. PDGFRA mutations with low allele frequencies (2-5%) were identified soley in imatinib-responders. Additionally, non-responders were characterized by an exclusive mutational signature linked to vesicular endocytosis and cytokine signaling as a resistance mechanism to pan-kinase inhibitor imatinib. Conclusion PDGFRA/B expression in tumour cells of therapy-resistant ALK-positive ALCL patients can discriminate genetically and functionally distinct lymphoma subgroups that are directly related to long-term treatment response to kinase inhibitor imatinib. Our data suggests that significant imatinib responses may be achieved in more than 80% of chemotherapy-resistant ALK+ ALCL cases.

The Overlap of Skin and Blood T-Cell Clones in Early-Stage Mycosis Fungoides

Introduction: Mycosis fungoides (MF) is the most common subtype of cutaneous T-cell lymphoma that initially starts in the skin but can progress to involve blood with significant mortality in late stages. Even in early stages and in the absence of blood involvement, changes in blood T-cell receptor (TCR) repertoire have been observed in MF patients. While prior work has explored the significance of dominant blood T-cell clones in the prognosis of early MF, the relationship between TCR sequences and T-cell repertoires of blood and skin in early-stage MF patients has not been characterized. Objectives: To determine the relationship of blood and skin T-cell repertories and to reassess the impact of dominant blood T-cell clones on selected outcome endpoints in early-stage MF. Materials and Methods: We used high-throughput sequencing to interrogate TCR sequences in blood and skin of MF patients without blood involvement at the Jefferson Cutaneous Lymphoma Clinic (Adaptive Biotechnologies). ImmunoSEQ Analyzer provided T-cell repertoire overlap metric (Morisita's index) and diversity measure (Simpson's clonality score). Time to systemic treatment (TTST) was calculated as the time from initial diagnosis to initiation of first systemic therapy. Results: 60 MF patients with no blood involvement were enrolled. 28% had a dominant clone in blood; of these, 18% were identical to dominant skin clones and 82% were distinct from the dominant clones identified in skin. We found that MF patients with discordant dominant T-cell clones in blood and skin had a longer TTST when compared to the identical clone cohort (P=0.0057) (Figure 1A). Furthermore, patients with discordant dominant clones had a lower degree of T-cell repertoire overlap between blood and skin (P<0.0001) and higher blood T-cell repertoire diversity scores (P=0.013) when compared to the identical clone group (Figure 1B). In all patients, the degree of T-cell overlap in blood and skin did not significantly change over a period of months to years or among skin biopsies obtained from different anatomical locations. Finally, in a subset of patients with discordant clones, the dominant skin clone did not appear to be detected in blood even at low frequencies. Conclusion: Our data highlight the importance of establishing clonal associations between dominant T-cell clones of the skin and blood in MF. We propose that early-stage MF patients with dominant clones in blood segregate into two cohorts with distinct prognoses and T-cell repertoires based on the identity of their peripheral T-cell clones. In addition, our findings suggest that not all MF patients have reservoirs of malignant T-cell clones readily available in peripheral circulation to seed new lesions in skin. Figure 1: A: Kaplan-Meier analyses of time to systemic treatment (TTST) in skin-limited mycosis fungoides (MF) patients with an identical dominant T-cell clone in blood and skin, a discordant dominant T-cell clone in blood and skin, and no dominant blood clones. NS- not significant (P =0.5274), ** (P =0.0057), *** (P <0.0003). B: Average Morisita's index for blood and skin overlap for patients in indicated groups of I: identical dominant clones in blood and skin, D: discordant dominant clones in blood and skin, and N: no dominant clone in blood. **** (P <0.0001).

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.

Targeting BCMA in Plasmablastic Lymphoma: Two Cases of Therapeutic Response to Teclistamab

Plasmablastic lymphoma (PBL) is an aggressive subtype of B-cell Non-Hodgkin lymphoma (B-NHL) with poor outcomes. PBL occurs more commonly in HIV-positive or immunocompromised patients, but it can also occur in immunocompetent patients. Despite anthracycline-based induction therapy, PBL is associated with chemotherapy resistance and early disease relapse, yielding a median overall survival of 7 to 15 months (Castillo JJ, et al. Blood. 2015). The advent of novel therapies altered the therapeutic landscape for many common subtypes of B-NHL, but progress in PBL is lacking due to the rarity of this disease and the lack of effective therapeutic targets. While PBL does not express many common B-NHL markers (e.g. CD19 or CD20), it does highly express B-cell maturation antigen (BCMA). However, data regarding the efficacy of therapies targeting BCMA in PBL is limited. Herein, we report two cases of relapsed/refractory PBL treated with the BCMA-targeting bispecific antibody teclistamab. Patient 1 was a 33 year old male without significant comorbidities when he was diagnosed with Stage IIE PBL after presenting with a chest wall mass. He was treated with six cycles of dose-adjusted EPOCH-V, followed by radiation to the involved region and a BEAM autologous hematopoietic stem cell transplant. Post-transplant imaging showed him to be in a CR on day 30 PET, but he developed recurrent PBL on his day 100 PET exam with osseus lesions. He was then treated with daratumumab and ICE chemotherapy for four cycles, with an initial resolution of osseus lesions. However, he developed relapsed disease with perilymphatic lung nodules. His PBL was confirmed to express BCMA and he was started on teclistamab monotherapy. Following one cycle of weekly teclistamab (1.5mg/kg), his post-treatment PET imaging demonstrated a complete response. He then underwent a consolidative allogeneic hematopoietic stem cell transplant from a matched unrelated donor. As of this report, he remains in a complete response based on his 30 day PET restaging imaging after transplant and without clinical evidence of disease more than 90 days after transplant. Patient 2 was a 60 year old male with medical history of comorbid CAD, stage IV chronic kidney disease, chronic back pain requiring opioid treatment, and peripheral arterial disease when he was diagnosed with Stage IV PBL after he was found to have mass-like thickening of his descending colon on a CT scan. He underwent partial colectomy, with pathology revealing PBL and his post-operative staging PET/CT scan noting osseus, splenic, and hepatic lesions consistent with advanced stage disease. He was initially treated with DA-EPOCH for six cycles with intrathecal methotrexate, which yielded an initial complete response, though he relapsed four months after completing therapy. He was then treated with gemcitabine, oxaliplatin, and daratumumab but progressed after eight cycles on treatment with abdominal and perisplenic masses confirmed on biopsy to be PBL He was then initiated on teclistamab, which was continued weekly. His treatment course was complicated by a viral pneumonia from which he recovered with IVIG and supportive measures. Following 2 total cycles of therapy, his repeat PET/CT imaging was consistent with a complete response (Figure 1), and he remains on weekly teclistamab therapy with no evidence of disease to date. The encouraging responses noted in our two cases illustrate the therapeutic potential of targeting BCMA using teclistamab in PBL. In our cases, teclistamab was a well tolerated therapy, even in our patient with significant comorbidities. This report provides a foundation for future prospective, multicenter clinical trials to evaluate the efficacy and safety of teclistamab in the treatment of relapsed and refractory PBL.

Genetic Subtyping Using Whole Exome Sequencing across Large B Cell Lymphoma Entities in a Series of 109 DLBCL and Plasmablastic Lymphoma Cases

Background: Diffuse Large B Cell Lymphomas are still a significantly heterogeneous disease with few molecularly defined entities. Recently genomic based algorithms have been proposed for DBCL NOS disease classification, including the Lymphgen tool 1. Other large B cell lymphoma entities, including High Grade BCL Dual Hit or plasmablastic lymphoma remain poorly characterized according to this molecular based clustering methods. Here we sought to apply this tool for disease classification in a series of 109 large B cell lymphoma cases derived from GELTAMO clinical trials (NCT01848132 and NCT2015-005390-21) and retrospective multicentric series to confirm its application across different large B cell lymphoma entities. Methods: We retrieved FFPE and liquid biopsy diagnostic samples from 109 cases and performed histopathological confirmation, FISH testing and whole exome sequencing (Agilent Sureselect v6) by NGS. Sequencing data and available fusion data for BCL2 and BCL6 were used to classify the cases according to Lymphgen (https://llmpp.nih.gov/lymphgen). Results: 109 cases were classified as different large B cell lymphoma entities, including 31 DLBCL NOS GCB type, 8 HGBCL/DLBCL DH/NOS, 41 DLBCL NOS non-GCB type, 22 plasmablastic lymphoma, 3 THRLBCL, 1 PMBL, 2 DLBCL NOS and 1 3B Follicular Lymphoma. After WES median Tumor Mutation Burden was 972. Overall genetic classification by Lymphgen was obtained in 53 cases (49%) with the remaining 56 cases considered unclassified (molecular subtype other/NOS). Of the genetically identified cases, 18 were classified as ST2 (33%), 15 were considered EZB (28%), 5 BN2 (10%) and 3 MCD (5%). Interestingly 12 (22%, overall, 11%) were genetically composite, including 8, ST2/EZB; 1, ST2/BN2; 1, ST2/MCD and 2 ST2/EZB/MCD. According to histopathological subtype 17 GCB type DLBCL were classified as EZB (8, 47%), ST2 (5, 30%) and BN2 (1, 6%). 3 cases (17%) were genetically composite. 6 out of 8 cases of HGBCL/DLBCL DH/NOS were classified as either EZB (2), ST2 (2) or composite EZB/ST2 (2). 19 non-GCB type DLBCL were classified as ST2 (5, 26%), BN2 (4, 21 %), EZB (3, 16 %) and MCD (3, 16%). 4 cases were genetically composite (21%). Interestingly, plasmablastic lymphomas showed ST2 genetic features, found in 5 out of 22 (23%) and composite ST2/EZB in 2 cases. Genes overrepresented in the ST2 cluster include TET2, PRRC2C, STAT3,DOCK8 and CLTC. Plasmablastic Lymphomas classified as other showed recurrent mutations in PRRC2C, PABPC1, TRRAP, PRKCB, EP300 and TP53. Conclusions: ST2 and EZB genetic groups stand as the most frequent genetic subtypes of DLBCL NOS. While ST2 is found in either GCB and non-GCB subtypes, EZB is found preferentially in cases with the GCB phenotype, including GCB type DLBCL and HGBCL/DLBCL DH. In comparison with already published series we found a relatively higher prevalence of the ST2 genetic subtype among DLBCL NOS. MCD and BN2 genetic subtypes are restricted to the non-GCB subtype, but its prevalence is relatively low. Importantly, a significant fraction of cases (~50%) is still genetically unclassified (molecular subtype NOS) using WES and FISH-derived fusion data. Proper identification of the A53 cluster and relevant dysregulated pathways in the molecular NOS group require more research. Specific large B cell lymphoma entities such as plasmablastic lymphoma show features of ST2 genetic subtype in a significant fraction of tumors. These features include JAK/STAT3 pathway activation related genes and fit well with already published data 2,3. In addition, recurrent mutations in TET2, involved in epigenetic regulation of gene expression and TRRAP, target of C-MYC transcriptional activation, were enriched in this molecular subtype of plasmablastic lymphoma. Importantly ~70% remained unclassified. Mutations in this group are recurrently found in PRRC2C as well as PABPC1, both involved in VEGFA-VEGFR2 signaling. In summary, DLBCL NOS molecular subtyping supplies exact molecular classification in ~50% of our cohort. ST2 and EZB subtypes constitute ~60% of the cases with a fraction of ~15% of composite ST2/EZB. Application of the molecular classifier to plasmablastic lymphomas shows intraspecific genetic diversity and points toward dysregulation of JAK/STAT, MAPK/Erk and VEGFA-VEGFR2 signaling as well as MYC transcriptional activation. REFERENCES 1. PMID: 32289277 2. PMID: 33225311 3. PMID: 32273478

Real-World Response Rates across Lines of Therapy Among Patients with Relapsed/Refractory Follicular Lymphoma

Background: Follicular lymphoma (FL) is the most common indolent subtype of non-Hodgkin lymphoma. Despite the generally indolent nature of the condition, there are subgroups of FL patients who may not have an indolent experience, with their disease not responding to multiple lines of therapy. Thus, optimization of novel therapy could improve patient outcomes. This analysis examined treatment patterns, overall response rates (ORR), and complete response (CR) rates by line of therapy (LOT) in relapsed/refractory (R/R) FL in third-line or later (3L+) therapy. Methods: This retrospective observational study was conducted using the COTA database, comprising electronic health records (EHR) from academic (50%) and community (50%) practices in the US. Adults with a confirmed diagnosis of FL, with 3L+ therapy initiation in 2010 or later, at least 3 months of follow-up, and any response assessment after 3L initiation were included. LOTs eligible for inclusion met the following conditions: treatment with an anti-CD20, alkylating agent, or lenalidomide, and no investigational drug in the selected LOT. In addition, patients with only 3L had that line selected; patients with more than 1 eligible LOT had only 1 LOT randomly selected for the analysis. Outcomes were assessed by FL International Prognostic Index (FLIPI), double refractory (DR) status, and type of therapy. DR status was defined as being refractory (disease progression or initiation of a new LOT in <6 months) to an anti-CD20 monoclonal antibody therapy and an alkylating agent. Chemoimmunotherapy (CIT) regimens included obinutuzumab/rituximab + bendamustine (OB/BR), rituximab/obinutuzumab+cyclophosphamide, doxorubicin, vincristine, and prednisolone (R/O+CHOP), R/O+CVP, R/O+other alkylating agent, and R/O+fludarabine and cyclophosphamide (FC). Novel therapies included lenalidomide + rituximab (R 2), phosphatidylinositol-3-kinase (PI3K) inhibitors, and chimeric antigen receptor T-cell therapy (CAR T). The proportion of patients with CR (as retrieved from clinician documentation in EHR) as the physician-reported response within each LOT was calculated. ORR was calculated as the proportion of patients with a CR or PR. Response rates were reported by LOT (3L, 4L, 5L+) and stratified by patient age (<65 vs ≥65 years), FLIPI score (low/intermediate vs high), and DR (not DR vs DR). Results: Overall, 240 patients with R/R 3L+ FL were included: 3L (n=140), 4L (n=55), and 5L+ (n=45). At 3L initiation, median age was 66 years and most patients were male (58.8%), White (89.6%), and had FL grade 1/2 (72.5%); 47.9% of patients were DR, 22.9% had novel therapy use, and 51.3% had CIT use. A total of 152 patients had FLIPI scores available, 38.2% of whom had high-risk scores at 3L initiation. Among all R/R 3L+ FL patients, ORR was 67.9%, with CR in 30.4% ( Figure 1). Response rates decreased across LOTs for both ORR (3L: 72.9%; 4L: 65.5%; 5L+: 55.6%) and CR (3L: 35.0%; 4L: 30.9%; 5L+: 15.6%) ( Figure 2). ORR was higher among all R/R 3L+ FL patients <65 years vs ≥65 years (75.5% vs 62.3%), as was CR rate (36.3% vs 26.1%). Among the subset of R/R 3L+ FL patients with a FLIPI score, those with low/intermediate risk vs high risk had a greater ORR (78.7% vs 58.6%) and CR rate (36.2% vs 20.7%). ORR was also higher for R/R 3L+ patients without DR status vs with DR status (73.0% vs 63.2%), as was CR rate (37.4% vs 24.0%). Patients receiving novel therapy 3L+ had an ORR of 70.9% and a CR rate of 27.3%. Among R/R 3L+ FL patients, more LOTs of CIT were associated with decreased response rates; patients with CIT in 1 LOT vs CIT in >2 LOTs had greater ORR (76.4% vs 69.2%) and CR rate (37.4% vs 26.9%). Conclusions: This analysis provides granular details on patients with R/R FL with poor prognosis. Patients with FL who progress to later LOTs have worsening response rates. This analysis included more patients with later LOTs than previously published reports, providing additional insight into response rates as treatment progresses. Lower response rates were observed among patients ≥65 years, those with a high-risk FLIPI score, and those with DR status. The high utilization of CIT in later LOTs, despite suboptimal response rates, especially among subgroups of patients with FL who may not have indolent experience of the disease, underlines the need for efficacious alternative therapies in patients with R/R 3L+ FL.

Real-World Overall Response Rate (ORR) of Diffuse Large B-Cell Lymphoma with Polatuzumab Vedotin-Based Theraphy, a Multicentric Study in Mexico

INTRODUCTION: Diffuse Large B-cell Lymphoma (DLBCL) is a prevalent and aggressive subtype of non-Hodgkin's lymphoma. Accurate diagnosis and timely treatment are crucial for improving patient outcomes. Polatuzumab vedotin has emerged as a promising therapeutic option in the management of Diffuse Large B-cell Lymphoma (DLBCL). Polatuzumab vedotin is a monoclonal antibody conjugated to a chemotherapeutic agent, monomethyl auristatin E (MMAE), which binds to the CD79b antigen specific to B cells and internalizes into malignant cells. (Hervé, et. al. NEJM 2022) POLARIX trial has shown that first-line treatment with the Pola-R-CHP combination, showed a progression-free survival benefit over the R-CHOP regimen at 2 years and had a similar safety profile, other prospective therapeutic trials have shown benefit of polatuzumab based therapy in Relapsed/Refactory DLBCL. (Herrera, et. al. Blood 2022) (Sehn, et. al JCO 2020) In Mexico, Polatuzumab + R-CHP (Pola-R-CHP) was recently approved for previously untreated or Relapse/Refractory (R/R) DLBCL patients and until this date to the best of our knowledge this is the first study in our country that evaluates response rates with polatuzumab-based protocols. METHODS: We conducted an observational, retrospective, multicenter study focusing on the effectiveness and safety of Pola-R-CHP in adult patients with previously untreated or R/R DLBCL across 12 private centers in Mexico. We collected data of 21 patients who received at least one dose of Pola-R-CHP between October 2022 and July 2023. The primary endpoint of the study was the overall response rate (ORR), defined as the sum of complete response (CR) and partial response (PR). We also described the type, incidence, severity of any adverse events (AEs) from the start of treatment to 1 month after the last infusion. Positron Emission Tomography response assessment was accordingly to Lugano criteria. AEs were assessed according to the National Cancer Institute Common Terminology Criteria of AEs and to minimize bias, a terminology dictionary was provided to all Centers. Descriptive analyses included medians and ranges for continuous variables, and frequencies and proportions for categorical variables. RESULTS: Twenty-one patients were enrolled with diagnosis of DLBCL, 8 females (38.1%) and 13 males (61.9%). The median age was 62 years (range = 34 - 77). Three patients (14.3%) were classified as R-IPI 0 points, 8 patients (38.1%) as 1-2 points and 10 patients (47.6%) as 3-5 points. Most patients (76.2%) were in stage III/IV with an ECOG performance status score of 0 - 1 (76.2%). Six patients (28.5%) were classified as Triple-Hit DLBCL subtype. Eight patients (38.1%) were previously untreated, 7 patients (33.3%) received Pola-R-CHP as second line, and 6 patients (28.6%) as third line treatment. Median number of cycles was 6 (range: 1 - 6). The ORR was 66.6%, with 13 patients (61.9%) with complete response and 1 patient (4.7%) with partial response. Complete response rates among first line patients and subsequent lines were 75% and 53.8% respectively. Thirteen (62%) patients received at least 6 cycles of treatment and 8 patients (38%) suspended treatment due to AEs(1 patient), progression (2 patients) or death (5 patients). Ten patients (47.6%) presented at least one AEs as enlisted in the table 2. CONCLUSIONS: Polatuzumab vedotin has emerged as an innovative therapeutic option in the management of DBLCL. The experience in developing countries is limited and the outcomes, unexplored. In our study, Pola-R-CHP ORR was 66.6% with an acceptable safety profile. We need to conduct studies with a larger group of patients and longer follow-up in order to determine OS and Progression Free Survival (PFS) and to introduce this protocol in routine treatment algorithms.