Large B-cell Lymphoma Patients Research Articles

Development and validation of the post-CAR prognostic index for large B-cell lymphoma patients after CAR-T progression in third or later line treatment

Chimeric antigen receptor (CAR) T-cell therapy fails to achieve durable responses in over 60% of relapsed/refractory (R/R) large B-cell lymphoma (LBCL) patients in the third or later line setting. After CAR-T failure, survival outcomes are heterogeneous and a prognostic model in this patient population is lacking. A training cohort of 216 patients with progressive disease (PD) after CAR-T from 12 Spanish centers was used to develop the Post-CAR Prognostic Index (PC-PI); primary endpoint was overall survival (OS) from CAR-T progression. Validation was performed in an external cohort from three different European centers (n = 204). The prognostic score incorporated five variables, assessed at time of PD to CAR-T: ECOG (> 0), hemoglobin (< 10 g/dL), LDH (≥ 2xULN), number of extranodal sites (> 1) and time from CAR-T to PD (< 4 months). Patients were classified in four risk groups with distinct OS (p-value < 0.05 in all comparisons). In the validation cohort, median OS in the low (31%), intermediate-low (26%), intermediate-high (17%) and high risk (26%) were 15.7, 7.1, 1.8 and 1.0 months, respectively (p < 0.05 in all comparisons). Results were consistent following adjustment for subsequent treatment. In the external cohort, the PC-PI showed a C-statistic of 0.79 (95%CI 0.76–0.82), outperforming IPI and R-IPI. In conclusion, the PC-PI score is a novel tool for OS prediction and could facilitate risk-adapted management of LBCL patients relapsing after CAR T-cells. Additionally, these results will help stratification and interpretation of trials and real-world data incorporating CART-exposed patients.

Antibiotic-induced loss of gut microbiome metabolic output correlates with clinical responses to CAR-T cell therapy

Antibiotic-induced microbiome dysbiosis is widespread in oncology, adversely affecting outcomes and side effects of various cancer treatments, including immune checkpoint inhibitors and chimeric antigen receptor T (CAR-T) cell therapies. In this study, we observed that prior exposure to broad-spectrum ABX with extended anaerobic coverage like piperacillin-tazobactam and meropenem was associated with worsened anti-CD19 CAR-T therapy survival outcomes in large B-cell lymphoma patients (n=422), compared to other ABX classes. In a discovery subset of these patients (n=67), we found that the use of these ABX was in turn associated with substantial dysbiosis of gut microbiome function, resulting in significant alterations of the gut and blood metabolome, including microbial effectors such as short-chain fatty acids (SCFAs) and other anionic metabolites, findings that were largely reproduced in an external validation cohort (n=58). Broader evaluation of circulating microbial metabolites revealed reductions in indole and cresol derivatives, as well as trimethylamine N-oxide, in patients who received ABX treatment (discovery n=40, validation n=28). These findings were recapitulated in an immune-competent CAR-T mouse model, where meropenem-induced dysbiosis led to a systemic dysmetabolome and decreased murine anti-CD19 CAR-T efficacy. Furthermore, we demonstrate that SCFAs can enhance the metabolic fitness of CAR-T cells, leading to improved tumor killing capacity. Together, these results suggest that broad-spectrum ABX deplete metabolically active commensals whose metabolites are essential for enhancing CAR-T efficacy, shedding light on the intricate relationship between ABX exposure, microbiome function and their impact on CAR-T cell efficacy. This highlights the potential for modulating the microbiome to augment CAR-T immunotherapy.

Genomic features of newly diagnosed large B cell lymphoma with or without subsequent disease progression.

Genomic analysis has the potential to both risk-stratify and inform management of patients diagnosed with large B cell lymphomas (LBCL). We analyzed cases of newly diagnosed LBCL patients treated with standard immunochemotherapy from three publicly available cohorts of patients on which fluorescence in situ hybridization (FISH) and next generation sequencing (NGS) were performed to determine the frequency of genomic alterations based upon development of disease progression. Cases from 698 patients were analyzed, with 201 experiencing disease progression and 497 no disease progression by 24 months post-diagnosis. When analyzing for the presence of MYC rearrangement and MYC-BCL2 dual-rearrangement/double hit, as well as variants predicted to result in alteration of protein function in 15 genes common to NGS panels from all 3 cohorts, only MYC rearrangement and TP53 mutation were associated with significantly higher odds of disease progression on multivariate analysis. Additionally, cases from patients who experienced disease progression demonstrated a high frequency of specific genomic alterations when analyzed by cohort or cell of origin classification by immunohistochemistry when available. Individual genomic features of LBCL cases may predict for development of disease progression in newly diagnosed patients treated with standard therapies, as well occur at higher frequencies in cases of disease progression based upon geographic region and/or cell of origin status. These novel findings support efforts to evaluate genomic features as biomarkers for response to specific therapies in subsets of LBCL patients who experience disease progression, which may lead to discovery of more effective treatment options.

The effect of plerixafor on autologous stem cell mobilization, cell viability, and apheresis challenges

Abstract Objective The aim of this study was to determine the efficacy of plerixafor for hematopoietic stem cell (HSC) mobilization prior to autologous stem cell transplantation (aSCT) for patients with multiple myeloma (MM) and various lymphomas, using an oncologist-guided HSC collection goal and markers of cell viability. Methods A retrospective chart review of all aSCT patients at Yale New Haven Hospital between 2017 and 2021 who met diagnostic criteria for MM, non-Hodgkin, or Hodgkin lymphoma (n = 382) was undertaken. Logistic regression evaluated plerixafor’s effect on meeting the individual’s HSC goal. The use of t-tests determined plerixafor’s relationship to HSC yield and analysis of variance testing assessed its effect on cell viability. Results Mobilization with granulocyte colony–stimulating factor (G-CSF) and plerixafor (odds ratio [OR] = 0.08; P &amp;lt; .05) relative to G-CSF alone was negatively associated with meeting the individual’s HSC goal. Diffuse large B-cell lymphoma in patients mobilized with plerixafor yielded fewer HSCs than those without plerixafor (t = –2.78; P = .03). Mobilization regimen (P = .13) had no association with HSC viability. Mobilization failure with plerixafor was rare but occurred in patients with multiple risk factors, including exposure to several rounds of HSC-affecting chemotherapy. Conclusion Plerixafor is effective across multiple diagnoses using an oncologist-driven HSC collection endpoint. Its association with mobilization failure is likely attributable to its use in patients predicted to be poor mobilizers.

Efficacy and safety of bendamustine-containing bridging therapy in R/R LBCL patients receiving CD19 CAR T-cells.

Bridging therapy (BT) after leukapheresis is required in most relapsed/refractory (R/R) large B-cell lymphoma (LBCL) patients receiving chimeric antigen receptor (CAR) T cells. Bendamustine-containing regimens are a potential BT option. We aimed to assess if this agent had a negative impact on CAR-T outcomes when it was administered as BT. We included R/R LBCL patients from six centers who received systemic BT after leukapheresis from February 2019 to September 2022; patients who only received steroids or had pre-apheresis bendamustine exposure were excluded. Patients were dividedinto two BT groups, with and without bendamustine. Separate safety and efficacy analyses were carried out for axi-cel and tisa-cel. Of 243 patients who received BT, bendamustine (benda) was included in 62 (26%). There was a higher rate of BT progressors in the non-benda group (62% vs. 45%, p = 0.02). Concerning CAR-T efficacy, complete responses were comparable for benda versus non-benda BT cohorts with axi-cel (70% vs. 53%, p = 0.12) and tisa-cel (44% vs. 36%, p = 0.70). Also, 12-month progression-free and overall survival were not significantly different between BT groups with axi-cel (56% vs. 43% and 71% vs. 63%) and tisa-cel (25% vs. 26% and 52% vs. 48%); there were no differences when BT response was considered. CAR T-cell expansion for each construct was similar between BT groups. Regarding safety, CRS G ≥3 (6% vs. 6%, p = 0.79), ICANS G ≥3 (15% vs. 17%, p = 0.68), severe infections, and neutropenia post-infusion were comparable among BT regimens. BT with bendamustine-containing regimens is safe for patients requiring disease control during CAR T-cell manufacturing.

Multicenter, randomized phase II study of epcoritamab for patients with large B-cell lymphomas achieving a partial response after CD19-directed CAR T-cell therapy (CAR-T).

TPS7100 Background: Despite the promising efficacy of CAR-T for patients with relapsed or refractory (R/R) large B-cell lymphomas (LBCL), more than 60% of patients will relapse, the majority of which occur in the first 6 months. Approximately 30% of patients with LBCL treated with CAR-T achieve a partial response (PR) on day 30 (D30) PET-CT assessment. Of patients in a D30 PR, 70% will eventually progress, yet the standard of care remains close observation. Early consolidative treatment strategies utilizing therapies with a different mechanism of action may improve outcomes, but there are currently no reliable biomarkers. Epcoritamab (Epco), a bispecific antibody directed against CD20 and CD3, has been approved by the FDA for LBCL patients who relapse after at least 2 lines of therapy. In the phase 2 study, Epco was associated with an overall response rate (ORR) of 63% and a complete response (CR) rate of 39%, including similar responses in a subset of patients who were relapsed 100 days post CAR-T. This study is a trial-in-progress that will evaluate the efficacy of epco compared to observation for patients with LBCLs achieving a PR on D30 post CAR-T PET-CT assessment. Methods: This is an investigator-initiated, randomized, phase II, multicenter, open-label study (NCT06238648) evaluating epco monotherapy for a fixed duration of 12 cycles compared to observation for LBCL patients with D30 PR after standard of care CAR-T. A maximum of 120 patients will be randomized 1:1 to epco or observation across 10 academic centers. Stratification factors include line of CAR-T (second vs third line) and costimulatory domain (CD28 vs 4-1BB). Key inclusion criteria include PET evidence of a D30 PR. non-bulky disease ( &lt;7.5cm), ANC of &gt;1000, hemoglobin &gt;7 g/dL if asymptomatic or &gt;8 if symptomatic, platelet count &gt;50,000. G-CSF, pRBCs and platelet transfusions are allowed. Key exclusion criteria include prior anti CD20xCD3 bispecific antibody therapy, ongoing or uncontrolled CRS or ICANS, and active or symptomatic CNS disease. Epco is administered subcutaneously at a dose of 0.16mg on day 1, 0.8mg on day 8, prior to full dose of 48mg on day 15. Epco is administered weekly in 28 day cycles (C) for C1-3, on day 1 and 15 of C4-9 and on day 1 of C10-12. PET-CT response is assessed by the 2014 Lugano criteria after 2 cycles, and then every 3 months during active treatment. The primary objective is efficacy, measured as conversion from D30 PR to CR. The secondary endpoints include frequency and severity of treatment emergent adverse events, ORR, duration of response, duration of complete response, progression free survival, event free survival, and overall survival. Peripheral blood samples will be collected pre-treatment and during treatment to assess for biomarkers of response and resistance. The study was activated in January 2024 and recruitment is ongoing. Clinical trial information: NCT06238648 .

Treatment outcomes in patients with large B-cell lymphoma after progression to chimeric antigen receptor T-cell therapy.

Over 60% of relapsed/refractory (R/R) large B-cell lymphoma (LBCL) patients who receive chimeric antigen receptor (CAR) T cells will experience disease progression. There is no standard next line of therapy and information in this setting is scarce and heterogeneous. We analyzed 387 R/R LBCL patients who progressed after CAR T cells from July 2018 until March 2022 in Spain and the United Kingdom. Median overall survival (OS) was 5.3 months, with significant differences according to the interval between infusion and progression (<2 months [1.9 months], 2-6 months [5.2 months], and >6 months [not reached]). After progression, 237 (61%) patients received treatment. Focusing on the first subsequent therapy, overall (complete) response rates were 67% (38%) for polatuzumab-bendamustine-rituximab (POLA), 51% (36%) for bispecific antibodies (BsAb), 45% (35%) for radiotherapy (RT), 33% (26%) for immune checkpoint inhibitors (ICIs), 25% (0%) for lenalidomide (LENA), and 25% (14%) for chemotherapy (CT). In terms of survival, 12-month progression-free survival and OS was 36.2% and 51.0% for POLA, 32.0% and 50.1% for BsAb, 30.8% and 37.5% for RT, 29.9% and 27.8% for ICI, 7.3% and 20.8% for LENA, and 6.1% and 18.3% for CT. Thirty-two (14%) patients received an allogeneic hematopoietic cell transplant with median OS not reached after a median follow-up of 15.1 months. In conclusion, patients with R/R LBCL who progress within the first 2 months after CAR T-cell therapy have dismal outcomes. Novel targeted agents, such as polatuzumab and BsAbs, can achieve prolonged survival after CAR T-cell therapy failure.

Patients with aggressive B-cell lymphoma receiving CAR T-cell therapy have a low rate of severe infections despite lack of universal antibacterial and antifungal prophylaxis.

Our aim was to describe the frequency and severity of infectious complications after chimeric antigen receptor (CAR) T-cell therapy in patients with large B-cell lymphoma (LBCL). We retrospectively reviewed clinical records of LBCL patients treated with CD19-targeted CAR T-cell therapy from July/2018 to December/2021 at our institution, and identified all infectious episodes from CAR T-cell infusion until disease progression, death or last follow-up. Overall, 137 patients were included. Thirty six percent had received ≥3 previous lines of therapy and 26% an autologous hematopoietic cell transplantation (auto-HCT). Cytokine release syndrome occurred in 87 (64%) patients. Antibacterial prophylaxis was not used in any patient; only 38% received antifungal prophylaxis. Sixty three infectious events were observed in 41 (30%) patients. Fifty two (83%) of the infectious events had at least one pathogen identified (bacteria [n = 38], virus [n = 11], and fungi [n = 3]). Most of the infectious events occurred during hospitalization for CAR-T treatment. Infection-related mortality was observed in two patients. Independent risk factors for infection included male gender, previous auto-HCT, ≥3 lines of treatment and pre-lymphodepletion neutropenia. Infections after CAR T-cell therapy in patients with lymphoma are frequent but generally not severe. A conservative and tailored antimicrobial prophylaxis seems to be a safe approach.

Abstract LB092: Novel tumor gene expression signatures predictive of outcome in large B cell lymphoma treated with CAR T cell therapy (axicabtagene ciloleucel)

Abstract We leveraged ZUMA-7, the first and largest, phase III randomized CAR-T cell clinical study of relapsed/refractory large B cell lymphoma (LBCL) in the 2nd line setting, to discover tumor gene expression (GE) signatures associated with outcome to anti-CD19 CAR-T cell therapy, Axicabtagene Ciloleucel (axi-cel). We performed GE profiling on pre-treatment LBCL tumor samples from 134 axi-cel-treated (safety dataset) patients using IO-360 Nanostring panel (769 genes). Multivariate analysis with penalized Cox models was conducted to identify genes whose expression (transcripts) associated with event-free survival (EFS), progression-free survival (PFS), and duration of response (DOR), leading to identification of two predictive GE signatures. For technical validation, the predictive value of these signatures was reproduced in a subset of ZUMA-7 samples profiled by RNA-seq (n=124). High levels (&amp;gt; median) of a favorable 6-transcript GE signature (6-GES) composed of CD19, CD45RA, CCL22, KLRK1, SOX11, and SIGLEC5 positively correlated with EFS (HR: 0.27, 95% CI: 0.16–0.44; P=1.82 × 10−8) and PFS (HR: 0.27, 95% CI: 0.16–0.46; P=1.35 × 10−7) in patients treated with axi-cel. The 6-GES may capture lymphomas with abundant adhesion molecules, a relatively low inflammation, and abundant expression of the targeted antigen (CD19). Conversely, high levels of an unfavorable 17-transcript GE signature (17-GES; CD45RO, BCL2, IL-18R1, TNFSF4 [OX40L], KLRB1 [CD161], KIR3DL2, ITGB8, DUSP5, GPC4, PSMB5, RPS6KB1, SERPINA9, NBN, GLUD1, ESR1, ARID1A, and SLC16A1) negatively correlated with Axi-cel EFS (HR: 6.19, 95% CI: 3.60–10.65; P=1.51 × 10−13) and PFS (HR: 7.58, 95% CI: 4.16–13.81; P=2.70 × 10−14). The 17-GES signature is consistent with a high level of immune infiltration and inflammation paralleled by the activation of immune-escape mechanisms, such as the upregulation of anti-apoptotic genes. Notably, the 17-GES was elevated at progression after axi-cel treatment (n=18). These signatures did not associate with outcome to 2nd-line SOC from ZUMA-7 (n = 122 for nanostring and n = 125 for ZUMA-7 RNAseq datasets, respectively), nor with outcome to 1st -line R-CHOP from two online datasets, indicating their predictive rather than prognostic value. In conclusion, our transcriptomic analysis of ZUMA-7 dataset identified novel GE signatures predictive of outcome with axi-cel. These GE signatures could support risk-stratification of LBCL patients. Citation Format: Yuan Tian, Justin Budka, Frederick L. Locke, Jason R. Westin, Christina To, Shilpa Shahani, Davide Bedognetti, Rhine R. Shen, Jorge Andrade, Simone Filosto. Novel tumor gene expression signatures predictive of outcome in large B cell lymphoma treated with CAR T cell therapy (axicabtagene ciloleucel) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB092.

Abstract 6549: Mechanistic models of tumor and patient heterogeneity explain and predict clinical outcomes of large B-cell lymphoma (LBCL) treatment

Abstract Introduction: Heterogeneity between patients and within tumors poses challenges to effective cancer treatment. Drug combinations can overcome heterogeneity by increasing the probability that a patient will have response to one or more drugs. This approach is successful in numerous disease settings, but technological advances have led to new approach to addressing heterogeneity: precision approaches to stratify patients into subpopulations with more uniform, stronger responses to specific drugs. These strategies can be implemented together to improve patient outcomes. We have developed computational mechanistic models of cancer treatment in the context of both sources of heterogeneity which explain and predict clinical outcomes of treatment of LBCL with combination therapy and CAR T-cell therapy. Combination therapy: Our novel population tumor kinetics (pop-TK) model simulates clinical combination therapy outcomes by implementing multidrug dose response functions in heterogeneous populations of tumor cells, within heterogeneous cohorts of patients. Informed by the outcomes of novel drugs in phase 2 trials in relapsed/refractory (r/r) patients, the pop-TK model accurately predicted of outcomes of seven first-line phase 3 trials of novel combinations. Most notably, informed by treatment of r/r LBCL with polatuzumab-vedotin (pola), the pop-TK predicted the success of modifying the standard treatment regimen (RCHOP) with pola before the clinical trial results were published. The pola combination improves overall survival (OS) and PFS in Activated B-Cell (ABC) LBCL (hazard ratio (HR): OS 0.3, PFS 0.4), but reduces OS (HR: 1.6) and does not improve PFS (HR: 1.0) in Germinal Center B-Cell (GCB) LBCL. The subtype specific difference in PFS was also predictable based on subtype results of r/r trials (predicted HR: ABC 0.3, GCB 0.9). CAR T-cell therapy: We used a population pharmacokinetic/pharmacodynamic (pop-PK/PD) model of CAR T-cell therapy to reproduce the PFS distribution and the distribution CAR T-cell abundance for CAR T therapy in r/r LBCL patients. The impact of tumor size on patient outcome in our model and in clinical studies led us to computationally explore the impact treating smaller tumors with CAR T-cell therapy on treatment outcomes. We found that using detectable circulating tumor DNA (ctDNA) as a biomarker for administering CAR T-cell therapy immediately after RCHOP increased the proportion of simulated patients without a second disease progression event by 30% (HR: 0.43 [0.34, 0.55]). Conclusions: The pop-TK model supports LBCL subtype biomarker for pola performance, and the pop-PK/PD model demonstrates that detectable ctDNA is a potential biomarker for early CAR T-cell administration. These examples of model-driven precision trial design have the potential to improve outcomes using readily-available biomarkers and existing therapies. Citation Format: Amy E. Pomeroy, Adam C. Palmer. Mechanistic models of tumor and patient heterogeneity explain and predict clinical outcomes of large B-cell lymphoma (LBCL) treatment [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6549.

Lisocabtagene Maraleucel (liso-cel) As Second-Line Therapy for R/R Large B-Cell Lymphoma in Patients Not Intended for Hematopoietic Stem Cell Transplantation (HSCT): Final Analysis of the Phase 2 PILOT Study

Lisocabtagene Maraleucel (liso-cel) As Second-Line Therapy for R/R Large B-Cell Lymphoma in Patients Not Intended for Hematopoietic Stem Cell Transplantation (HSCT): Final Analysis of the Phase 2 PILOT Study

Early failure is still a poor prognostic factor in patients with relapsed or refractory large B-cell lymphoma in the era of CAR T-cell therapy.

Patients with refractory or relapsed (R/R) large B-cell lymphoma (LBCL) refractory to first-line chemotherapy or with early relapse have poor outcomes. While chimeric antigen receptor (CAR) T-cell therapy has impressive efficacy after two or more lines of chemotherapy, it's still uncertain if these outcomes remain consistent in the context of third-line CAR T-cell therapy. We conducted a retrospective study of 107 R/R LBCL patients. Patients with relapse 12 months or more after their first-line chemoimmunotherapy (late failure: n = 25) had significantly longer overall survival (OS) than patients with refractory disease or relapse within 12 months (early failure: n = 82) (median OS: not achieved vs. 18.4 months; P < 0.001). Among patients who proceeded to autologous hematopoietic stem-cell transplantation (auto-HSCT), those with late failure had significantly longer event-free survival (EFS) than those with early failure (median EFS: 26.9 vs. 3.1 months; P = 0.012). However, no significant difference in EFS was detected among patients who underwent CAR T-cell therapy (median EFS: not reached vs. 11.8; P = 0.091). Cox regression with restricted cubic spline demonstrated that timing of relapse had significant impact on EFS in patients with auto-HSCT but not in patients with CAR T-cell therapy. Of patients who were scheduled for CAR T-cell therapy, those with late failure were significantly more likely to receive CAR T-cell therapy than those with early failure (90% vs. 57%; P = 0.008). In conclusion, patients with early failure still experienced poor outcomes after the approval of third-line CAR T-cell therapy.

The Post-CAR Prognostic Index (PC-PI): A New Prognostic Score to Predict Overall Survival in Large B-Cell Lymphoma Patients Progressing after Chimeric Antigen Receptor T-Cell Therapy

Introduction: Chimeric antigen receptor (CAR) T-cell therapy fails to achieve durable responses in 60% of relapsed/refractory (R/R) large B-cell lymphoma (LBCL) patients in the third or later line setting. There is no standard treatment after CAR T-cell therapy progression and a wide range of outcomes are observed in this patient population. Besides the interval between CAR T-cell infusion and progressive disease (PD), data regarding prognostic factors at time of progression are scarce. Our aim was to develop a new prognostic tool to predict overall survival (OS) after CAR T-cell therapy progression with easily-available markers from routine clinical practice. Methods: First, we performed a retrospective data collection at 12 Spanish centers of R/R LBCL patients who progressed after CAR T-cell therapy in the third or later line setting from September 2018 until June 2022 (training cohort, TC). We analyzed a total of 15 variables, including pre-CAR T-cell therapy characteristics (gender, histology, primary refractory disease, previous hematopoietic transplant, number of previous lines) and values collected at time of progression to CAR T-cells (age, stage, extranodal sites, ECOG, hemoglobin, neutrophils, platelets, LDH, best response to CAR T-cells, time from CAR T-cell infusion to PD). The primary endpoint was OS from date of progression to CAR T-cell therapy. A stratified Cox model was used to estimate hazard ratios (HRs) using post-progression treatment as a stratification factor. We used LASSO regression with minimum lambda to identify which variables had the highest prognostic impact on OS. Additionally, the factors with a lower contribution were eliminated to create a parsimonious model. The C-statistic was used to evaluate its discrimination. We examined the performance of the International Prognostic Index (IPI) score and Revised IPI (R-IPI) in this setting. Finally, we tested the score in an external validation cohort (VC) which included a comparable patient population from 3 European countries. Results: Among the 216 LBCL patients included in the TC, most were male (66%), had an ECOG of 1 (48%) and stage IV disease (71%) at time of CAR T-cell therapy progression. Median time from CAR T-cell infusion to PD was 2.5 months (95CI% 1.9-2.9) and median follow-up from progression was 15 months. Salvage treatment was classified into 3 subgroups, including immunotherapy or targeted agents (43%), chemotherapy or radiotherapy (20%) and palliative care (38%). To build the prognostic score, a total of 5 variables were selected. Each marker received 1 point (given the similar HR [1.48-1.77]), if they met defined criteria: ECOG (&amp;gt;0), hemoglobin (&amp;lt;10 g/dL), LDH (&amp;gt;2 x upper normal limit), number of extranodal sites (&amp;gt;1) and time from CAR T-cell infusion to PD (&amp;lt;4 months). Patients with 0-1 points were classified as low risk, 2 points as intermediate-low risk, 3 points as intermediate-high risk and 4 or 5 points as high risk. In the TC, the 4 risk groups showed statistically significant differences in OS (Figure 1). In the low-risk group (n=39 [18%]), the median OS [mOS] was not reached; in the intermediate-low risk (n=56 [26%]) mOS was 7.3 months (HR=2.89, p=0.002); in the intermediate-high risk (n=57 [26%]) mOS was 4.9 months (HR=4.81, p&amp;lt;0.001) and in the high risk (n=64 [30%]) mOS was 1.8 months (HR=6.69, p&amp;lt;0.001). In terms of post-relapse therapies, both the chemo/radiotherapy and the immunotherapy groups showed a balanced patient distribution, from low to high risk (32%, 35%, 14% and 19% vs 22%, 32%, 30% and 16%, respectively). The VC included 204 patients with a similar patient distribution in the 4 prognostic risk groups (35%, 25%, 12%, 27%). The mOS for each of these groups was 15.2, 5.3, 2.9 and 0.9 months, respectively. Each group had distinct OS outcomes when compared with all the other risk groups (p&amp;lt;0.05 for each comparison) (Figure 2). Finally, our model presented a C-index of 0.712 for the TC and 0.811 for the VC, outperforming both the IPI (0.647 [TC] and 0.691 [VC]) and R-IPI (0.632 [TC] and 0.683 [VC]). Conclusions: The Post-CAR Prognostic Index (PC-PI) is a clinically useful tool for OS prediction and risk-adapted treatment planning in LBCL patients progressing after CAR T-cell therapy. In addition, our results will help stratification in clinical trials which include patients with prior CAR T-cell therapy.

CD22 CAR T Cell-Related IEC-HS Is Associated with an IFN-γ Cytokine Signature

Introduction Chimeric antigen receptor T-cell therapy targeting CD22 (CAR22) shows promise for patients with relapsed / refractory B-cell acute lymphoblastic leukemia (ALL) and large B cell lymphoma (LBCL) (Fry et al. Nat Med 2018; Baird et al. Blood 2020). The overall response rate for CAR22 in adults who received prior CD19 CAR therapy is 100% and 68% in ALL and LBCL respectively (Tandem 2023) (NCT04088890). However, 33% of pediatric ALL patients who received CAR22 developed immune effector cell-associated hemophagocytic lymphohistiocytosis-like syndrome (IEC-HS) (Shah et al. JCO 2020). IEC-HS is characterized by hyperferritinemia, cytopenias, coagulopathy and end organ damage. Pediatric ALL data suggest many cytokines including IFN-γ, IL-1β, IL-18 and TNF-α are upregulated in IEC-HS (Ishii et al. JCI 2020, Lichtenstein et al. Blood 2021). Here, we report the clinical features and cytokines associated with IEC-HS after CAR22 infusion in predominantly adult subjects with ALL and LBCL. Methods Plasma was collected weekly from Day 0 to 28 for 54 patients (ALL: n = 16, LBCL: n = 38; adult: n = 51, pediatrics: n = 3) who were treated with CAR22 manufactured using an automated, closed-system Miltenyi CliniMACS Prodigy device. Three dose levels were tested (ALL: 3 x 10 5 cells/kg, LBCL dose level 1 (DL1): 1 x 10 6 cells/kg, LBCL dose level 2 (DL2): 3 x 10 6 cells/kg). Clinical characteristics associated with IEC-HS were retrospectively collected and graded according to consensus criteria (Hines et al. TCT 2023). Eighty cytokines were quantified in batch via multiplexed fluorescence immunoassay (Luminex) to generate mean fluorescent indices (MFIs). Unsupervised hierarchical clustering using Euclidean distance and ward.D2 linkage were employed to analyze cytokine dynamics. Statistical analyses were performed using R (v 4.2.2). Results 8 of 54 (15%) patients developed IEC-HS, all were ≥18 years old. 5 patients had LBCL, 3 had ALL. 5 cases were grade 2, 3 were grade 4. Median onset was D+12 (range 8 - 21). All patients had prior CRS with median onset at D+1 (range 0 - 9). The 3 ALL patients had ongoing CRS and spectral overlap with IEC-HS at time of diagnosis whereas LBCL patients' CRS resolved prior to IEC-HS onset. IEC-HS patients had significant increases in inflammatory markers (ferritin, CRP, LDH, triglycerides), coagulation markers (INR, PTT), cytopenias (hemoglobin, platelets) and transaminases (Table 1). Patients most commonly received high-dose glucocorticoids, tocilizumab and anakinra. Additional agents for grade 4 IEC-HS included anti-thymoglobulin, dasatanib and emapalumab. 5 of 8 patients developed serious infections requiring IV antimicrobials including bacteremia, invasive fungal infections and viral reactivation. 5 patients with IEC-HS died after achieving complete response: 3 due to IEC-HS and concomitant infection, 1 from t-AML and 1 lost to follow up. IEC-HS occurred more frequently at higher doses in LBCL where multiple doses were tested (DL2: 33% vs DL1: 7%, p = 0.08). Peak serum CAR22 concentration was markedly elevated in patients who developed IEC-HS compared to those who did not (median 648 vs 42 cells/µL, p&amp;lt;0.001). Unsupervised hierarchical clustering performed on serial cytokine measurements identified a signature of IFN-γ-related cytokines including CXCL9, CXCL10, TNFα, FasL, IL6 and IL18 as being closely related in IEC-HS (Figure 1). Most cytokines in the signature peaked at D+14, consistent with onset of clinical IEC-HS. Peak levels of nearly all cytokines in the interferon-γ cluster were significantly elevated in IEC-HS patients compared to patients who did not develop IEC-HS, and this cluster contained most cytokines with significant increases in peak levels (Figure 1). Conclusions IEC-HS is a potentially life-threatening toxicity associated with CAR22 across age and underlying malignancy. The high rates of non-relapse mortality and severe infections in this study highlight the importance of understanding the immune dysregulation underlying IEC-HS. Higher CAR22 dose and expansion were associated with IEC-HS, indicating optimal dosing as a potential preventive strategy. The observed IFN-γ cytokine signature is consistent with myeloid cell activation and Th1 T-cell skewing that likely contributes to IEC-HS pathogenesis. These cytokines may be amenable to therapeutic intervention and further study of approaches targeting JAK/STAT and IFN-γ are warranted.

Resistance Mechanisms Impacting Bispecific Antibody (BsAbs) and Chimeric Antigen Receptor (CAR) T-Cell Therapy Outcomes in Large B Cell Lymphoma (LBCL) Patients

Introduction: BsAbs and CAR T-cell therapy have revolutionized the treatment landscape of patients with relapsed/refractory (R/R) LBCL. Regrettably, less than 40% of patients will attain durable responses, and determinants of response remain unclear. Our aim was to identify tumoral characteristics that can predict resistance to CAR T-cell therapy and BsAbs in LBCL patients. Methods: We retrospectively collected clinical data and obtained pre-treatment formalin-fixed and paraffin-embedded specimens prior CAR T-cell and BsAb treatment from 56 LBCL patients from 4 centers. Targeted NGS was performed to identify variants and copy number variations (CNVs) across a custom gene panel of 200 genes. These include lymphoma related genes, and genes involved in tumor antigen presentation, B and T lymphocyte interaction, and cell death pathway. Variables assessing response where Overall Response Rate (ORR), Complete Response Rate (CRR), Progression-Free Survival (PFS), and Overall Survival (OS). To ascertain each gene's influence on these endpoints, a logistic model was used for ORR and CRR comparisons, while Kaplan-Meier and Cox methods were employed to analyze PFS and OS. Results: A total of 56 patients were included in the study, 36 patients treated with CAR T-cell and 36 with BsAbs (16 patients received both). Samples were obtained for 31 patients prior to CAR T-cell therapy (CAR T-cell cohort) and 34 cases prior to BsAbs (BsAbs cohort). Baseline characteristics of the patient population are shown in Table 1. In summary, median age was 62 years, 57% were male, 42% had a previous indolent lymphoma and median previous lines were 2 (range 1-4). Best response included CRR in 59%, with a median PFS and OS of 13.6 (CI95% 5.98 - Not reached [NR]) and 29.5 (CI95% 15.7 - NR) months, respectively. Median follow-up for the full cohort was 18.7 months (CI95% 15.1 - 24). As per the CAR T-cell cohort, ORR and CRR were 81% and 68%, respectively. Median PFS and OS for CAR-T-cell cohort was 29.4 months (CI95% 5.98 - NR) and NR, respectively. Regarding the BsAb cohort, ORR and CRR were 66% and 50%, respectively. Median PFS and OS was 10 (CI95% 5.16 - NR) and 22.5 (CI95% 14.4 - NR) months, respectively. For the full cohort, the most frequently altered genes, considering both mutations and CNVs, were KMT2D (66%), TP53 (60%), CREBBP (58%), IGLL5 (51%), REL (42%), EZH2 (38%), BCL2 (38%), TNFRSF14 (37%), SGK1 (32%) and KLHL6 (32%) (Figure 1). The most frequent CNVs were gains of 2p16.1 (34%), 3q28 (15%), 6p(14%), 11q (12%), 21q (12%), 3q (10%); and losses of 17p (32%), 6q (26%), 1p36.32 (25%), 13q14.2 (18%), 19p13.3 (18%), 4q35.1(16%), (10q23.31 (12%), 9p21.3 (10%). Focusing on the CAR T-cell cohort (n=31), mutations and/or deletions in EP300 (7%, n=2)( p=0.01) and KLHL6 (n=2, 7%) ( p=0.04) were associated with an inferior PFS. In addition, mutations and/or deletions in KLHL6 ( p=0.02) and EP300 (n=3, 10%) ( p=0.05), and amplifications in MYC (n=3,10%) ( p=0.031) were associated with shorter OS. No differences in PFS and OS were oberved in patients with mutations and/or deletions in TP53 (n=19, 63%). Regarding RHOA patients with mutations or deletions (n=2, 7%) did not present an inferior PFS ( p=0.88) or OS ( p=0.52). The analyzed alterations did not show an impact on response rate. In terms of patients who received BsAbs (n=34), we observed that mutations and/or deletions in TP53 (n=19, 58%) ( p=0.04) , RHOA (n=5, 15%) ( p=0.05) and GNAI2 (n=5,15%) ( p=0.02)were associated with aninferior PFS. Mutations and/or deletions in TP53 (p=0.04) , RHOA (p=0.009) , GNAI2 ( p=0.01) and CD274(PDL1)-PDCD1LG2(PDL2) (12%, n=3) ( p=0.01) were associated with an inferior OS. Regarding MYC, 8 cases were mutated (n=2, 6%), amplified (n=5, 15%) or both (n=1, 3%), but these alterations were not associated with an inferior PFS (p=0.46) or OS ( p=0.27). Again, no impact on response rate was observed for patients carrying alterations. Conclusions: In our study, a pattern of genetic alterations predicting worse OS was observed in patients treated with CAR T-cells ( KLHL6 EP300 and MYC) and BsAbs (TP53, RHOA, PDL1, PDL2, GNAI2). This important information will aid in the development of targeted strategies to overcome resistance and improve treatment outcomes.

Metabolic Reprograming of Exhausted Intratumoral CD8+ T-Cell Underlies Anti-Tumor Activity of Sumoylation Inhibitors in Large B Cell Lymphoma

Immune checkpoint inhibitors (ICI) targeting PD1 have revolutionized our approach to solid tumors and Hodgkin lymphoma, but they have not been effective in treating Large B Cell Lymphoma (LBCL). In prior work, we used single cell spatial profiling of human tumors to show that exhausted CD8 tumor and TREG populations were associated with PD1 resistance in LBCL (Colombo et al. Blood Adv 2022). Here we show, using a syngeneic model of LBCL, that PD1 resistance is associated with lower CD8+ T-cell basal metabolic rate (BMR) in tumor infiltrating lymphocytes (TIL), and that treatment with the covalent SUMOylation inhibitor (SB-4826) increases the metabolic rate of TIL by metabolic reprograming. Single cell metabolic profiling of human LBCL is on-going and will be presented as well. In summary these studies demonstrate that metabolic dysfunction of T cells in LBCL underlie resistance to PD1 checkpoint inhibitors and that this can be overcome by treatment with SUMOlyation inhibitors. Direct measurement of intra-tumoral metabolic state is difficult to perform on clinical samples, however large tumor size is hypothesized to be a surrogate for increased metabolic derangement. As tumors expand and become more metabolically active themselves, infiltrating immune cells experience decreased O2 tension as well as nutrient deprivation, ultimately leading to decreased anti-tumor immune responses. In support of this idea, it has been observed that high metabolic tumor volume at baseline predicts survival in LBCL patients, independent of their initial response to therapy. We have shown that mice with established (&amp;gt;125mm 3) A20 tumors are resistant to anti-PD1 therapy. However, A20 bearing mice treated ~5 days post implantation are responsive to anti-PD1 therapy. To understand these findings, we examined sensitive (small) and resistant (large) A20 tumors by flow cytometry analysis and found that resistant tumors had lower relative numbers of T cells, lower absolute numbers of CD8+ T cells, increased absolute numbers of TREG and a strikingly decreased CD8/TREG ratio. Additionally, the resistant tumors had increased absolute numbers of pre-exhausted and exhausted CD8+ T cells as well as decreased BMR. Small ubiquitin-like modifiers (SUMO) proteins regulate a variety of cellular processes in tumor and immune cells and inhibitors of SUMOylation have shown anti-tumor activity in a variety of preclinical tumor models with potential synergy with checkpoint inhibitors targeting PD-1 (Cannon et al. Cancer Res, 2023). We demonstrate that a dose of 100mg/kg of SB-4826 led to a complete response in all mice treated (Fig. 1A) and we also show that this effect is dependent on CD8+ T-cells and elicits a long term memory response, with 0 of 15 mice in remission developing tumor upon rechallenge. A low dose (25mg/kg) of SB-4826 failed to elicit a response in any of the mice treated while anti-PD1 therapy elicited a response in 1/6 mice (Fig. 1A). Combination of 25mg/kg SB-4826 with anti-PD1 therapy demonstrated synergism with a response in 3/6 mice (Fig. 1A). We also demonstrate that global SUMOylation levels are higher in PD1+ TIM3+ CD8+ TILs compared to PD1- TIM3- CD8+ T-cells, suggesting that SUMOylation may be acting as a negative regulator of T-cell function. Using SCENITH (Arguello et al. Cell Metabolism 2020) for single cell metabolic studies, we demonstrate that SB-4826 increases the BMR (Fig. 1B), mitochondrial dependency and proliferative capacity of tumor infiltrating PD1+ TIM3+ CD8+ T-cells (TILs). While both SB-4826 and PD1 inhibition led to increased CD8+ TIL numbers, SB-4826 led to increased BMR in CD8+ TILs while PD1 inhibition did not affect CD8+ TILs BMR. Additionally, PD1 inhibition significantly decreased CD8+ TILs mitochondrial dependency for metabolism, while SB-4826 increased mitochondrial dependency (Fig. 1B). Additionally, we recapitulate these metabolic enhancements in an in vitro system of T-cell activation, further confirming a T-cell intrinsic effect following SB-4826. Mechanistically, we found that SB-4826 led to increased HIF-1a levels in both CD4+ and CD8+ cells following TCR activation, likely through stabilization of HIF-1a due to decreased SUMOylation-dependent turnover (Cheng J et al. Cell 2007). We hypothesize that metabolic reprograming of CD8 T-cells through increased HIF-1a is the basis for synergy between SUMOylation inhibition and immune checkpoint inhibitors in LBCL.

Long-Term Efficacy and Immune Reconstitution with Bendamustine As a Lymphodepleting Agent for Axicabtagene Ciloleucel (Axi-Cel) in Patients with Refractory or Relapsed Large B-Cell Lymphoma (LBCL)

Introduction: Lymphodepletion (LD) is crucial for the expansion and persistence of CAR T cells. Fludarabine in combination with cyclophosphamide (FC) is the LD standard regimen. A national fludarabine shortage in 2022 necessitated the exploration of alternative LD regimens. Bendamustine (benda) is a purine analog and an alkylating chemotherapy that has been used as an LD agent for tisagenlecleucel (Ghilardi et al.,2022). However, there is no data for benda LD in other commonly used CART products for relapsed or refractory non-hodgkin lymphoma (rel/ref NHL). Early safety, efficacy, and expansion kinetics data were presented previously (Bharadwaj, ASH 2022). We are now reporting long-term efficacy and immune reconstitution data. Methods: 84 consecutive patients with relapsed/refractory LBCL treated with axi-cel were included in this single-institution study. 27 patients who received Bendamustine lymphodepletion (90mg/m2 on days -4 and -3) were compared to a preceding 57-patient FC cohort. Response, survival, and cytopenia data were collected closest to the 12-month time point for all patients who had not progressed. Response was assessed using the Lugano 2014 criteria, while toxicities were evaluated using the CTCAE version 5.0 and the ASTCT grading. To reduce the influence of confounding variables in this study, a covariate balance propensity score weighting approach (IPTW) was implemented. Covariates included age, sex, presence of bridging therapy, IPI score at apheresis, number of prior therapy lines, absolute lymphocyte count at leukapheresis, prior auto SCT, and pre-lymphodepletion LDH, ALC, ANC, and platelet count. Continuous outcomes were compared using the Mann-Whitney U test, categorical outcomes using chi-square tests, and time-to-event outcomes using a log-rank test weighted in the IPTW sample. Statistical significance was considered when p &amp;lt; 0.05. All analyses were conducted in R 4.3.0. Results: There was no significant difference in the best complete response (CR) rate and best overall response rate (ORR) between the two groups, with a CR rate of 71.9% for FC and 74% for bendamustine (p = 0.182), and an ORR of 89.4% for FC and 85.1% for bendamustine (p = 0.502). For the FC group, 9-month progression-free survival (PFS) and overall survival (OS) were 63.16% (95% CI: 49.29% to 74.19%) and 78.95% (95% CI: 65.92% to 87.45%), respectively with a median follow-up of 15.5 months (IQR: 13.6, 16.8). 9-month PFS and OS point-estimates for the bendamustine group were 70.37% (95% CI: 49.4% to 83.94%) and 77.41% (95% CI: 56.41% to 89.18%), respectively, with a median follow-up of 9.5 months (IQR: 8.6, 9.8). No significant difference was found between groups in either 9 months PFS ( P=0.055) or 9 months OS ( P=0.6290). Median PFS and OS have not been achieved for either group [Figure 1]. Bendamustine was effective in achieving severe lymphodepletion, with a median absolute lymphocyte count (ALC) nadir of 0.11 K/ul (IQR: 0.04, 0.17) occurring within one day after axi-cel infusion. In comparison, the FC group had a lower median ALC nadir of 0.03 K/ul (IQR: 0.01, 0.06) occurring on the day of axi-cel infusion ( P=0.01). Both cohorts showed a similar pattern of lymphocyte recovery over 1, 3, and 6 months. Median ALC counts at 9-12 months post-infusion indicated better lymphocyte recovery in the bendamustine group with a median ALC of 1.55 K/ul (IQR: 1.04, 1.94) compared to 0.96 K/ul (IQR: 0.58, 1.23) in the FC group ( P=0.043) [Figure 2]. There was no significant difference in the recovery of absolute neutrophil count, hemoglobin, and platelets. Updated efficacy analysis and immune reconstitution data including T-cell, B-cell, and NK cell recovery will be reported at the time meeting, as all patients will have completed at least one year of follow-up by September 2023. Discussion: Bendamustine lymphodepletion prior to axi-cel therapy showed comparable efficacy and safety outcomes to the standard FC regimen in relapsed/refractory LBCL patients. Bendamustine demonstrated effective lymphodepletion and better lymphocyte recovery at 9-12 months post-infusion compared to FC cohort. These findings suggest that bendamustine may be an acceptable alternative lymphodepleting regimen. Prospective studies, ideally randomized control trial, are warranted.

Distinct Genetic and Fragmentomic Signatures of Plasma Ctdna Synergize and Resolve Clinical Challenges in Patients with Large B-Cell Lymphoma

Introduction Seizing the full potential of lymphoma circulating tumor DNA (ctDNA) for scientific discoveries and accurate precision medicine tools requires diminished dependence on tumor tissues, enhanced detection of rare variants and harnessing non-random ctDNA fragmentation patterns for non-invasive profiling. Establishment of such tools is pivotal to overcome clinical challenges set by pervasive heterogeneity and different treatment responses in the patients with large B-cell lymphoma (LBCL). Methods Using our previous data on targeted and whole-genome sequencing (WGS) levels of lymphoma ctDNA (Meriranta, 2022), we constructed a novel targeted sequencing assay with B-cell lymphoma-relevant loci and used duplex barcoding to improve analytical sensitivity. We optimized fragment pattern conservation by comparison of different library preparation strategies and established the requirements for exhaustive and reproducible duplex sequencing with error-rate down to 2-4/10^6. We examined replicate samples and in vitro and in silico dilution series of ctDNA spike-in in healthy donor cell-free DNA (cfDNA) to determine the limits of tumor-naïve variant calling, ctDNA quantification and minimal residual disease (MRD) detection. We applied this assay to &amp;gt;500 plasma, tumor and whole-blood DNA samples from primary LBCL patients treated in biomarker driven Nordic phase II trial (Leppä, 2022) and correlated the results with biological and clinical data (Fig A). Results Ultra-sensitive charting of pretreatment ctDNA revealed profound spatial heterogeneity in LBCL patients at diagnosis. Plasma profiles were formed by contributions from multiple cell subpopulations with divergent hypermutations and driver events, some exhibiting convergent trajectories diverged even at early B-cell stages preceding germinal center entrance. The cell populations represented in the diagnostic biopsies contributed an unpredictable proportion of the overall ctDNA pool and majority (63%) of the subclonal ctDNA mutations were not detected in the matched tissues resulting in conflicting genotypes between different materials. Dominant but not subclonal TP53 mutations in the ctDNA associated with poor survival also uncovering patients with no TP53 aberrations in their diagnostic biopsies. On therapy, allele fractions of lymphoma mutations, regardless of their clonal status, declined with early responding patients being MRD negative after two treatment cycles with excellent survival. At the end-of-therapy, Duplex-MRD predicted progression with excellent specificity (98%) but with limited negative predictive value (90%) and sensitivity (47%). Fragmentomic analysis revealed that duplex-recovery was suboptimal for subnucleosomal cfDNA fragment lengths with the highest mutational content. Remarkably, harnessing cfDNA fragments with only single-strand recovery (i.e. non-duplex) for combined ‘Dual-MRD’ enhanced ctDNA detection, translated to better distinction of early responders and resolved most false-positive end-of-therapy FDG-PET scans (Fig A). Besides enriched for shorter fragment sizes, additional non-random structural features of ctDNA molecules extended to their distinct repertoire of fragment nucleotide end motifs (Fig B). Notably, mutant fragments carried less physiological DNAse1L3 nuclease end signatures than their reference counterparts or healthy donor cfDNA (Fig B). Distinct fragmentomic elements of ctDNA molecules contained unexploited utility for non-invasive disease phenotyping and detection that we spanned to shallow (~10x) WGS breadth in independent validation series of lymphoma and healthy donor samples. Conclusion By harnessing synergy between duplex technology, single-strand recovery and distinct fragmentomic features, we discovered novel characteristics in lymphoma ctDNA that correlate with disease biology and improve non-invasive disease profiling to overcome limitations of tumor biopsies and clinical estimates.

Predictive Value of Pre-Infusion FDG‐PET/CT Parameters for Clinical Outcomes and Toxicities in Relapsed/Refractory (R/R) Large B-Cell Lymphoma (LBCL) Following CAR-T Cell Therapy

Introduction: CD19-targeting chimeric antigen receptor (CAR) T-cell therapy has demonstrated significant efficacy in patients with relapsed/refractory (R/R) non-Hodgkin lymphoma but is associated with serious adverse effects such CRS and ICANS. Pre-infusion disease burden has been investigated as a potential predictor of clinical outcome and toxicity. FDG-PET/CT derived metabolic tumor volume (MTV) and total lesion glycolysis (TLG) are quantitative indicators of this baseline tumor load. We aim to assess the predictive value of pre-CART PET metrics on outcome and toxicity in R/R large B-Cell Lymphoma (LBCL) following CAR-T cell therapy. Method: We conducted a retrospective single site study of 25 consecutive patients with R/R LBCL treated with CAR-T therapy in our institution between May 2020 and October 2022, All patients underwent FDG-PET/CT imaging pre-CAR-T infusion (PET-0) and at day 30 post infusion (PET-1). The images were reviewed by two expert lymphoma PET physicians. Metabolic parameters including MTV, TLG (both calculated using a relative threshold of 40%), SUVmax and Deauville score were calculated. PET-1 was classified as complete metabolic response (CMR, Deauville score 1-3) or non-CMR (Deauville score 4-5) as per the Lugano classification. Results: 25 patients were analyzed , Based on the median MTV (74,6 mL), TLG (379,4), SUVmax (11,8) values, patients were divided into two groups “low” and “high”. The median follow-up was 12 months. Patients with low pre-infusion MTV and TLG had significantly superior day 30 CMR rates (84,6% vs 25%, p= 0.001 &amp; 80% vs 20%, p = 0.001 respectively). Pre-infusion SUVmax ( p = 0.29 ) and Deauville score ( p = 0.103), however, did not predict response to treatment. In our population, pre-infusion PET parameters were not associated with CRS or ICANS . Patients with low pre-infusion MTV and TLG had significantly superior PFS (MTV: p=0.02; TLG: p=0.019) and OS (MTV: p=0.017; TLG: p=0.05), Pre-infusion SUVmax had no statistical significant impact on OS ( p = 0.61) or PFS ( p = 0.37) Conclusion: In our study, pre-infusion quantitative PET metrics, TLG and MTV, predict response and outcomes of CART therapy in R/R LBCL. Our results highlight the importance of adequate disease control before CAR-T administration and the value of pre-infusion FDG-PET/CT as a predictor of outcomes in R/R LBCL patients treated by CAR-T-therapy.

Joint Analyses of Serum Proteins and Circulating Tumor DNA Improves Risk Assessment and Subtype Stratification in Large B-Cell Lymphomas

Introduction Inadequate dismantling of clinical and biological heterogeneity is an obstacle for improving outcome in large B-cell lymphoma (LBCL). Circulating tumor DNA (ctDNA)-based stratification holds great potential in resolving these challenges. However, the assessment is limited to genetic content, and excludes host response from the estimates. Previously, we have shown that an inflammatory signature identified from the pretreatment serum proteins translates to poor survival, and multiple serum proteins correlate with LBCL genetic subtypes. To further improve risk stratification and molecular characterization of LBCL from the liquid biopsy, we co-analyzed serum protein and ctDNA levels in LBCL patients treated in two Nordic Lymphoma Group (NLG) trials. Materials and methods Our discovery cohort consisted of 122 patients less than 65 years of age with clinically high-risk (age adjusted IPI ≥ 2) LBCL, who were treated in NLG-LBC-06 trial with immunochemotherapy. Plasma and serum samples were collected prior to treatment. Cell free DNA was extracted from plasma and sequenced with in-house adapted duplex sequencing platform using custom targeted panel of 347 lymphoma driver genes and immunoglobulin loci. An inflammation score was composed as log transformed mean of the most pertinent inflammatory serum proteins detected in the inflammatory signature (IL10, IL2RA, CXCL9, IL18, GZMB, PD-L1 and IFNG), and their levels were measured using antibody-based Luminex assay (pg/ml, R&amp;D Systems). In addition, CCL17 and TNFRSF13B levels were analyzed to uncover their associations with genetic subtypes. An independent cohort of 91 patients treated in our previous NLG-LBC-05 trial was used for validation. Results Combined analysis of serum proteins and ctDNA identified a group of patients (n=12, 10%) with high serum inflammation scores and ctDNA burden (≥ 3.75 hGE/ml), which translated to poor survival compared to the patients with low concentrations of either inflammatory proteins or ctDNA, or both (progression free survival, PFS, hazard ratio 7.33, 95%-CI 2.59-20.79, P &amp;lt; 0.001, Figure 1A). This finding was confirmed in the independent validation cohort. In both cohorts, the combined analysis showed higher specificity in survival prediction as compared to the ctDNA-based assessment alone, indicating that inflammatory serum markers alongside with ctDNA can identify those patients who, despite of having high ctDNA burden, have excellent survival. Beyond inflammation, the levels of serum TNFRSF13B and CCL17 correlated with mutations associating with non-germinal center diffuse large B-cell lymphoma (non-GCB DLBCL)/MCD subtype and primary mediastinal B-cell lymphoma/grey-zone lymphoma (PMBCL/GZL), respectively. For example, serum TNFRSF13B levels correlated positively with mutations in MCD genes, such as CD79B, SETD1B, PIM2 and PRDM1, and negatively with mutations in EZB genes EZH2 and CREBBP in both cohorts (P &amp;lt; 0.05, Figure 1B). Supporting our earlier findings, high CCL17 levels revealed a group of patients diagnosed with DLBCL not otherwise specified or high-grade lymphoma but with a mutational landscape resembling PMBCL/GZL, including mutations in TNFAIP3, ITPKB, B2M, BTG1 and STAT6 (P &amp;lt; 0.05). Conclusion Our findings demonstrate that co-analysis of inflammatory serum markers along with the ctDNA improves ctDNA-based survival prediction. Moreover, analysis of serum proteins refines molecular classification. Altogether, joint analysis of serum proteins and ctDNA provides new tools to dismantle LBCL heterogeneity.