Advanced Roles Research Articles

IMMUNE CONTEXTURE ANALYSIS IN POLARIX SUGGESTS RESPONSE TO POLA‐R‐CHP TREATMENT REDUCES TUMOR MICROENVIRONMENT DEPENDENCY

IMMUNE CONTEXTURE ANALYSIS IN POLARIX SUGGESTS RESPONSE TO POLA‐R‐CHP TREATMENT REDUCES TUMOR MICROENVIRONMENT DEPENDENCY

17th International Conference on Malignant Lymphoma, Palazzo dei Congressi, Lugano, Switzerland, 13 - 17 June, 2023.

Introduction: Patients with B-cell lymphoma have poorer antibody responses to COVID-19 vaccines compared to patients with other malignancies. However, the immune responses are heterogeneous and its association with clinical outcomes are poorly understood. Here, we study the association between antibody and cellular responses with the outcomes from COVID-19 infection from the PROSECO study. Methods: THE UK PROSECO study is a prospective observational cohort study evaluating COVID-19 vaccine response in people with lymphoma. Peripheral blood antibody titres (anti-spike (S) IgG by Mesoscale Discovery), antibody avidity (surface plasmon resonance) and IFNγ T-cell responses (ELISpot) against spike protein after two to four COVID-19 vaccines, and clinical outcomes data were collected. Results: 524 patients (92 Hodgkin lymphoma, 180 aggressive B non-Hodgkin lymphoma (B-NHL), 234 indolent B-NHL and 18 peripheral T-cell lymphoma) were included: 334 (84·3%), 315 (79·5%) and 266 (67·1%) participants were eligible for post-two, three and four vaccine dose analysis, respectively. Breakthrough infections (BTI) occurred in 20 (5.9%), 40 (12.7%) and 36 (13.5%) participants after two, three and four vaccine doses. Of 96 participants with BTI, 12 (12.5%) needed hospitalisation. No deaths were observed due to COVID-19 infection. No differences were observed in T-cell responses between BTI and non-BTI groups, but 4/9 (44.5%) hospitalised BTI cases had undetectable cellular and antibody responses. There was no association between antibody titres and infection episodes after two vaccine doses, but antibody titres were associated with lower BTI risk after three or four vaccine doses on multivariable analysis. Intriguingly, the antibody threshold associated with infection risk was lower after four than three vaccine doses (41 vs. 820 BAU/mL). We also observed stronger antibody binding avidity to SARS-CoV-2 spike receptor-binding domain (RBD) proteins from Wuhan and Omicron BQ.1 variants, with increasing vaccine doses, i.e., fourth versus third dose: 10-fold increase (p: <0.01); fourth versus second dose:100-fold-increase than the second dose (p: <0.0001) (see Figure). The research was funded by: the Blood Cancer UK Vaccine Research Collaborative, which is led by Blood Cancer UK in partnership with Myeloma UK, Anthony Nolan and the British Society for Haematology; a Cancer Research UK Advanced Clinician Scientist Fellowship to SH Lim; Cancer Research UK/National Institute for Health Research (NIHR) Southampton Experimental Cancer Medicine Center; NIHR Southampton Clinical Research Facility (Southampton Research Biorepository) and NIHR Southampton Biomedical Research Center; NIHR Great Ormond Street Biomedical Research Center and the NIHR Oxford Biomedical Research Center and CRUK Experimental Cancer Medicines Center. Keywords: Lymphoid Cancers, Other: Covid-19, Therapeutics and Clinical Trials in Lymphoma, vaccination Conflicts of interests pertinent to the abstract. M. Ahearne Research funding: Pfizer C. P. Fox Consultant or advisory role: Astra Zeneca G. P. Collins Consultant or advisory role: Astra Zeneca and Pfizer Research funding: Pfizer A. J. Davies Honoraria: Astra Zeneca and Janssen Research funding: Astra Zeneca and Janssen S. H. Lim Honoraria: Astra Zeneca

PHASE 1B OPEN‐LABEL STUDY OF LONCASTUXIMAB TESIRINE IN COMBINATION WITH OTHER ANTICANCER AGENTS IN PATIENTS WITH RELAPSED/REFRACTORY B‐CELL NON‐HODGKIN LYMPHOMA (LOTIS‐7)

Introduction: Combining agents with different mechanisms of action may enhance treatment (Tx) efficacy in patients (pts) with relapsed/refractory (R/R) B-cell non-Hodgkin lymphoma (B-NHL). Loncastuximab tesirine (loncastuximab tesirine-lpyl; Lonca), an FDA-approved, CD19-directed, antibody-drug conjugate indicated for R/R diffuse large B-cell lymphoma (DLBCL), showed significant efficacy and manageable toxicity in a phase 2 trial in pts with R/R DLBCL. In preclinical models, Lonca + polatuzumab vedotin (Pola) showed improved efficacy. CD20 × CD3 T-cell–engaging antibodies and Lonca target different antigens; combining these is expected to increase efficacy. The safety and activity of Lonca combined with other agents in pts with R/R B-NHL will be evaluated in LOTIS-7. Methods: LOTIS-7, a phase 1b, open-label, multicenter, multiarm study (NCT04970901), will enroll ∼200 pts with B-NHL in part 1 (dose escalation, 60 pts) and part 2 (dose expansion, 140 pts). Part 2 may include specific subpopulation(s) of B-NHL informed by part 1. Primary endpoints are frequency and severity of adverse events (AE), serious AE, dose-limiting toxicities, and frequency of AE-related dose modifications. Secondary endpoints are overall response rate; duration of response; complete response rate; progression-free, relapse-free, and overall survival; Lonca concentrations; and antidrug antibody titers. Planned arms include Lonca + Pola (arm C), glofitamab (arm E), or mosunetuzumab (arm F). Arm C enrollment is open: pts are treated with Lonca + Pola as an outpatient infusion. In part 1, arm C pts receive Lonca at escalating doses (90-150 µg/kg) and Pola (1.8 mg/kg) on day 1 of each 3-week cycle; pts in arms E and F will receive Lonca 150 µg/kg for 2 cycles, then 75 µg/kg for subsequent cycles + glofitamab (2.5 mg on cycle [C]1 day [D]8, 10 mg on C1D15, and 10 or 30 mg for C2-12 D1, arm E) or mosunetuzumab subcutaneously (5 mg on C1D1, 15 or 45 mg for C1D8, and 45 mg for C1D15 and C2-8 D1, arm F) after initial step-up dosing. Lonca Tx may continue for up to 1 year or until disease progression, unacceptable toxicity, or other discontinuation criteria. Key eligibility criteria include age ≥18 years, pathologic diagnosis of R/R B-NHL (2016 WHO classification), measurable disease (2014 Lugano classification), Tx failure/intolerance, ≥2 lines of prior therapy (LOT) for part 1 (≥1 LOT for part 2), and ECOG performance status of 0-2. Pts previously receiving a study drug could not enroll in that respective study arm. Pts who received a stem-cell transplant within 60 days (100 days for arms E/F) before study Tx; received allogeneic stem cell or solid organ transplant (arms E/F); have lymphoma with active CNS involvement, ascites, edema, or effusion; or have significant comorbidities are excluded. The study opened in December 2021; as of January 2023, 12 pts have been enrolled and 9 treated in the Lonca + Pola arm. Encore Abstract - previously submitted to ASCO 2023 The research was funded by: ADC Therapeutics SA; medical writing: CiTRUS Health Group. Keywords: aggressive B-cell non-Hodgkin lymphoma, combination therapies, ongoing trials Conflicts of interests pertinent to the abstract. B. T. Hess Consultant or advisory role ADC Therapeutics, Bristol-Myers Squibb/Celgene M. M. Solh Research funding: Partner Therapeutics Other remuneration: Bristol-Myers Squibb, Amgen, AbbVie, Seattle Genetics M. Gandhi Honoraria: GlaxoSmithKline, TG Therapeutics, Karyopharm Therapeutics, Janssen Oncology Y. Wang Employment or leadership position: ADC Therapeutics America, Inc. Stock ownership: Johnson & Johnson (immediate family member) Y. Qin Employment or leadership position: ADC Therapeutics America, Inc. Stock ownership: ADC Therapeutics America, Inc. Research funding: ADC Therapeutics America, Inc. E. Yu Employment or leadership position: ADC Therapeutics America, Inc. Stock ownership: ADC Therapeutics America, Inc., Merck, Zentalis, Karuna Therapeutics, Biomarin P. L. Zinzani Consultant or advisory role Celltrion, Gilead Sciences, Janssen-Cilag, Bristol-Myers Squibb, Servier, Sandoz, MSD Oncology, Roche, EUSA Pharma, Kyowa Kirin, Takeda, Secura Bio, TG Therapeutics, Novartis, ADC Therapeutics, Incyte, BeiGene Other remuneration: MSD Oncology, EUSA Pharma, Novartis G. P. Collins Consultant or advisory role Roche, Takeda, Incyte, Pfizer, MSD Oncology, Celgene, BeiGene, Daiichi Sankyo, Celleron Therapeutics, ADC Therapeutics Honoraria: Roche, Takeda, Gilead Sciences, Pfizer, Novartis, Daiichi Sankyo, Incyte, Celleron Therapeutics, MSD Oncology, BeiGene, ADC Therapeutics, AstraZeneca Research funding: MSD Oncology, Celgene, Bristol-Myers Squibb, Amgen, Pfizer Educational grants: Roche, Takeda Other remuneration: Roche, Takeda, Novartis, Gilead Sciences

17th International Conference on Malignant Lymphoma, Palazzo dei Congressi, Lugano, Switzerland, 13 - 17 June, 2023.

Introduction: Bruton tyrosine kinase inhibitors (BTKi) block B-cell receptor pathway signaling, leading to growth inhibition and cell death in malignant B-cells. First-generation BTKi, ibrutinib (ibr) revolutionized treatment; however, inhibition of off-target kinases such as EGFR, HER2, TEC, and CSK may be associated with toxicities, including diarrhea, rash, bleeding, and atrial fibrillation (Afib), that limit its use. Zanubrutinib (zanu), a potent and selective next-generation BTKi, maximizes BTK occupancy and minimizes off-target effects. Here, we characterized the overall safety/tolerability of zanu and compared it with ibr in patients (pts) with B-cell malignancies using the zanu clinical safety database. Methods: Safety data were pooled from 10 clinical trials of zanu monotherapy; 2 of the included studies (ASPEN; ALPINE) compared zanu head to head with ibr. Pts with CLL/SLL, MCL, MZL, WM, FL and other B-cell malignancies were included. Treatment-emergent adverse events (TEAEs) were summarized using MedDRA preferred terms; adverse events of special interest (AESI) were defined using pooled terms. Rates of TEAEs, exposure-adjusted incidence rates (EAIRs), and prevalence over time of AESI were assessed. Results: Pooled analyses included 1550 pts treated with zanu. Median zanu exposure was 28.6 months with 31.2% of pts having treatment exposure of ≥36 mo. Most common nonhematologic AEs were upper respiratory tract infection (29.0%), diarrhea (19.9%), contusion (19.4%), cough (17.2%), and rash (16.2%); grade ≥3 nonhematologic AEs occurring in ≥5% of pts included pneumonia (7.9%) and hypertension (7.4%). The most common serious AE was pneumonia (7.5%). Zanu discontinuation due to AE occurred in 12.3% of pts; AEs leading to dose reduction occurred in 9.6%. Disease progression was the most common cause of death (7.2%); deaths attributed to AEs occurred in 5.6% of pts, and most (3.2%) were due to infections including COVID-19-related AEs. The most common AESI in the pooled zanu population and in ibr-treated pts from ASPEN and ALPINE (N = 422) were infections and hemorrhage (Table). With the exception of neutropenia, EAIRs were numerically lower for zanu versus ibr, most notably hypertension (0.57 vs. 1.15 person/100 person-months), anemia (0.54 vs. 0.84 person/100 person-months), and atrial fibrillation or flutter (0.15 vs. 0.70 person/100 person-months). Prevalence of zanu AESI tended to remain constant or decrease with longer follow-up. Conclusions: As BTKi therapy requires continuous treatment, long-term tolerability and low treatment discontinuation rates are needed for successful outcomes. zanu was well tolerated, with generally mild-to-moderate AEs that tended not to lead to treatment discontinuation. Prevalence of AESI generally trended down over time without emergence of new safety signals, supporting zanu as a good option for long-term treatment. Encore Abstract - previously submitted to EHA 2023 The research was funded by: BeiGene Keywords: Aggressive B-cell non-Hodgkin lymphoma, Chronic Lymphocytic Leukemia (CLL) Conflicts of interests pertinent to the abstract. J. R. Brown Consultant or advisory role: Abbvie, AstraZeneca, BeiGene, Eli Lily/Loxo, Genentech, Octapharma, Oncternal, MingSight, TG Therapeutics Research funding: BeiGene, Gilead, iOnctura, Loxo/Lilly, MEI Pharma, SecuraBio, Sun, TG Therapeutics B. Eichorst Consultant or advisory role: Janssen, AbbVie, Gilead, AstraZeneca, BeiGene, MSD, Lilly Honoraria: Roche, AbbVie, BeiGene, AstraZeneca, MSD Research funding: Janssen, Gilead, Roche, AbbVie, BeiGene, AstraZeneca Educational grants: BeiGene P. Ghia Consultant or advisory role: AbbVie, AstraZeneca, BeiGene, BMS, Janssen, Lilly/Loxo Oncology, MSD, Roche Honoraria: AbbVie, AstraZeneca, BeiGene, BMS, Janssen, Lilly/Loxo Oncology, MSD, Roche Research funding: AbbVie, AstraZeneca, BMS, Janssen W. Jurczak Consultant or advisory role: Abbvie, Astra Zeneca, BeiGene, Lilly, Roche, Takeda Research funding: Abbvie, Astra Zeneca, BeiGene, Janssen, Lilly, Roche, Takeda B. S. Kahl Consultant or advisory role: BeiGene, Pharmacyclics, AstraZeneca, Abbvie, Janssen Other remuneration: BeiGene N. Lamanna Consultant or advisory role: Abbvie, AstraZeneca, BeiGene, Eli Lily/Loxo, Genentech, Janssen, Pharmacyclics Research funding: Abbvie, AstraZeneca, BeiGene, Eli Lily/Loxo, Genentech, Octapharma, Oncternal, MingSight, TG Therapeutics T. Robak Honoraria: AstraZeneca, BeiGene, Janssen, Abbvie, Octapharma, Regeneron, GSK Research funding: BeiGene,OctaPharma, AstraZeneca, Janssen, Regeneron, GSK, Educational grants: AstraZeneca M. Shadman Consultant or advisory role: Abbvie, Genentech, AstraZeneca, Sound Biologics, Pharmacyclics, Beigene, Bristol Myers Squibb, Morphosys/Incyte, TG Therapeutics, Innate Pharma, Kite Pharma, Adaptive Biotechnologies, Epizyme, Eli Lilly, Adaptimmune, Mustang Bio, Regeneron, Merck, Fate therapeutics, MEI pharma and Atara Biotherapeutic Research funding: Mustang Bio, Celgene, Bristol Myers Squibb, Pharmacyclics, Gilead, Genentech, AbbVie, TG Therapeutics, Beigene, AstraZeneca, Sunesis,Atara Biotherapeutics, Genmab, Morphosys/Incyte C. S. Tam Honoraria: BeiGene, AbbVie, Janssen Research funding: Janssen, AbbVie Other remuneration: BeiGene L. Qiu Consultant or advisory role: Janssen, Astra Zeneca, Takeda, Roche, Abbvie, Beigene A. Cohen Employment or leadership position: BeiGene Stock ownership: BeiGene M. Zhang Employment or leadership position: BeiGene T. Salmi Employment or leadership position: BeiGene International GmbH Stock ownership: BeiGene Ltd. J. Paik Employment or leadership position: BeiGene L. Wang Employment or leadership position: BeiGene Stock ownership: BeiGene J. Zhang Employment or leadership position: BeiGene Stock ownership: BeiGene H. Ma Employment or leadership position: BeiGene Stock ownership: BeiGene A. Tedeschi Consultant or advisory role: BeiGene, AstraZeneca, AbbVie, Janssen Honoraria: BeiGene, AstraZeneca, AbbVie, Janssen

Prognostic impact of HLA‐I neoantigen‐specific CD8+ T cells in limited‐stage follicular lymphoma

Introduction: Follicular lymphoma (FL) is the most common indolent NHL. Recently, we demonstrated in limited and advanced stage FL (LSFL, ASFL), that patients with longer remissions had raised clonally expanded intratumoral CD8+ T cells (Tobin, JCO 2019). Durable remissions occur in ∼50% of LSFL patients whereas ASFL is incurable. However, little is known regarding the immunological features associated with this difference. We hypothesized HLA-I neoantigen (neoAg)-specific CD8+ T cells may play a role. Methods: The discovery cohort comprised 101 patients with diagnostic paraffin embedded tissue from the TROG99.03 LSFL clinical trial (MacManus, JCO 2018), in which stage I/II patients were randomized to involved field radiation (IFRT) only or combined modality therapy between 2000 and 2012 (PET from 2006). Contemporaneous validation cohorts were (a) AusLSFL: 60 PET staged, stage I FL patients from Australia (treatment miscellaneous), and (b) CanLSFL: 60 PET staged, stage I FL patients drawn principally from Canada (IFRT only). Digital gene expression (NanoString), targeted sequencing (330 genes), and germline HLA-typing was performed. Mutations observed by sequencing were used to predict neoAgs in TROG99.03 tissues using 8 algorithms (PVACseq) and filtered according to strong binding affinity to HLA-I over wild-type (TESLA consortium guidelines; Wells, Cell 2020). Results: CD8A gene expression was tested for prognostic significance. In TROG99.03, elevated intratumoral CD8A (by MaxStat) was associated with ∼2-fold improvement in PFS for all patients: HR 0.45 (CI: 0.77–0.26, p = 0.0053) and stage I only patients: HR 2.4 (CI: 1.2–4.6, p = 0.036). In keeping with a relationship between CD8+ T cell infiltration and tumor antigen presentation, raised expression of NLRC5 (a transcriptional HLA-I activator) was also associated with superior PFS: HR 0.48 (CI: 0.99–0.24, p = 0.024). CD8A significance was confirmed in both validation cohorts (whereas NLRC5 was validated in AusLSFL only). In keeping with recent IHC CD8 protein data (Los-de Vries, Bld Adv 2022), CD8A gene expression was raised in stage I LSFL vs. 68 ASFL patients treated with immunochemotherapy (p = 0.02). Mutational profiling was concordant with published LSFL data, with CREBBP and KMT2DA most frequent. NeoAg calling methods including functional assays for neoAg peptide binding were confirmed in a separate cohort of fresh FL tissues. 59% of TROG99.03 tissues had ≥1 neoantigens detected. Importantly, unsupervised hierarchical clustering showed 2-fold enrichment of samples with neoantigens among those with high vs. low HLA-I. Conclusions: Raised CD8A is associated with favorable prognosis in LSFL. Our data suggests disease control involves populations of expanded HLA-I neoAg-specific T cells. These findings have implications for novel immunotherapeutic strategies designed to increase the rate of durable remissions. The research was funded by: National Health and Medical Research Council, Australia; Leukaemia Foundation; Mater Foundation Keywords: Diagnostic and Prognostic Biomarkers, Indolent non-Hodgkin lymphoma, Microenvironment Conflicts of interests pertinent to the abstract. C. Keane Honoraria: Takeda, Roche, AZ, MSD, Beigene C. Cheah Consultant or advisory role: Roche, Janssen, Gilead, AstraZenecca, Lilly, TG therapeutics, Beigene, Novartis, Menarini, Daizai, Abbvie, Genmab. BMS Honoraria: BMS, Roche, Abbvie; MSD, Lilly R. Kridel Research funding: Abbvie Educational grants: Eisai M. K. Gandhi Research funding: Beigene, Janssen

NATHALI‐01: A PHASE 1/2A TRIAL OF UCART20X22, AN ALLOGENEIC DUAL CAR T‐CELL THERAPY FOR PATIENTS WITH RELAPSED/REFRACTORY B‐CELL NON‐HODGKIN LYMPHOMA (NHL)

Introduction: Autologous CAR T-cell therapies have been transformative in the treatment of selected blood cancers. Despite this remarkable success, long term studies on patients treated with CD19 or CD22 CAR T-cells revealed the emergence of relapses often due to antigen loss. The therapeutic options after CAR T-cell relapses are limited, underscoring the urgent need to develop novel therapies to improve current survival rates. In addition, there is a need to develop allogeneic “off-the-shelf” therapies that are readily available at the time of treatment decision and that overcome the development limitations of current autologous approaches. To address these challenges, UCART20x22, the first allogeneic dual CAR T-cell product candidate targeting two well-validated antigens in B-cell malignancies, CD20 and CD22, was generated from normal healthy donor T cells using a bicistronic lentiviral construct to express both CARs. TALEN® gene editing technology was used to inactivate the TRAC and CD52 genes to both minimize Graft-vs-Host Disease and allow for the use of alemtuzumab (an anti-CD52 monoclonal antibody) in the lymphodepleting regimen. UCART20x22 displays strong activity against tumor cell lines with diverse CD20/CD22 antigen combinations, as well as increased activity against cells presenting both targets simultaneously using in vitro cytotoxic and proliferation assays. The activity of UCART20x22 cells persists against tumor cells expressing both antigens (CD20, CD22) or only one. In a pre-clinical in vivo model carrying subcutaneous lymphoma tumors expressing different antigen combinations in a single mouse, UCART20x22 cells provide efficient in vivo clearance of tumor cells expressing one or two antigens in a dose dependent manner. Furthermore, in primary NHL patient samples expressing diverse CD22 and CD20 antigen levels, UCART20x22 displays robust and specific cytotoxic activity and IFN-γ release in all tested combinations. Methods: NatHaLi-01 (NCT05607420) is a Phase1/2a open-label dose-finding and dose-expansion study to evaluate the safety, expansion, persistence, and clinical activity of UCART20x22 in subjects with relapsed or refractory B-Cell NHL. Primary endpoints are safety, tolerability, and determining the MTD/RP2D of UCART20x22. Additional endpoints are anti-lymphoma activity and describing the expansion and trafficking of UCART20x22. Eligibility criteria include age 18‒80y, lymphoma cell expression of either or both CD20 and CD22, and ≥ 2 prior treatment regimens including autologous CD19 CAR T-cell therapy if eligible. After lymphodepletion with FCA (fludarabine 30 mg/m2 × 3d, cyclophosphamide 0.5g/m2 × 3d, alemtuzumab 12 mg on D1, 24 mg on D2, D3), patients will receive a single infusion of UCART20x22 at a flat dose level ([DL]; DL1-50 × 106 cells, DL2-150 × 106 cells, and DL3-450x106 cells). The trial is currently open for enrollment. The research was funded by: Cellectis, S.A. Keywords: aggressive B-cell non-Hodgkin lymphoma, cellular therapies, ongoing trials Conflicts of interests pertinent to the abstract. E. Bachy Honoraria: Roche, Takeda, Kite/Gilead, BMS, Novartis, Pfizer, Incyte, ADC Therapeutics Research funding: Amgen, BMS Other remuneration: Kite/Gilead, BMS, Novartis, Pfizer A. Ramakrishnan Consultant or advisory role Novartis, AztraZeneca, Genmab, Janssen A. Alfonso Consultant or advisory role BMS, Syros, Jazz Pharma, Astellas Honoraria: Novartis, BMS, Abbvie, Jazz Pharma, Janssen Research funding: Astra Zeneca P. A. Riedell Consultant or advisory role AbbVie, Genmab, ADC Therapeutics, Pharmacyclics, Novartis, BMS, Kite/Gilead, Nurix Therapeutics, Nektar Therapeutics, Takeda, Intellia Therapeutics, Sana Biotechnology, BeiGene, Janssen, and CVS Caremark Honoraria: Novartis Research funding: BMS, Kite/Gilead, Novartis, MorphoSys, CRISPR Therapeutics, Calibr, Xencor, Fate Therapeutics, Roche, and Tessa Therapeutics Other remuneration: Kite Pharma G. Cartron Consultant or advisory role Roche, BMS, Abbvie, Onwards therapeutics, MedXcell, MabQi Honoraria: Roche, BMS, Jansen, Gilead, Novartis, Abbvie Educational grants: Roche P. Barba Honoraria: Allogene, Amgen, BMS, Kit/Gilead, Incyte, Jazz Pharmaceuticals, Miltenyi Biomedicine, Nektar Novartis and Pierre Fabre S. Meadows Employment or leadership position: Cellectis, Inc. Stock ownership: Cellectis, Inc. A. LaCroce Employment or leadership position: Cellectis, Inc. Stock ownership: Cellectis, Inc. D. Thomas Employment or leadership position: Cellectis, Inc. Stock ownership: Cellectis, Inc. C. Poirot Employment or leadership position: Cellectis, S.A. Stock ownership: Cellectis, S.A. K. J. Newhall Employment or leadership position: Cellectis, Inc. Stock ownership: Cellectis, Inc. D. J. Lee Employment or leadership position: Cellectis, Inc. Stock ownership: Cellectis, Inc. M. G. Frattini Employment or leadership position: Cellectis, Inc. Stock ownership: Cellectis, Inc. J. Abramson Consultant or advisory role AbbVie, Astra-Zeneca, BeiGene, BMS, Caribou Biosciences, Cellectar, Century Therapeutics, Epizyme, Genentech, Genmab, Incyte, Interius, Janssen, Kite Pharma, Kymera, Lilly, Morphosys, Mustang Bio, Ono Pharma, Regeneron, Takeda

Outpatient administration of mosunetuzumab in US community practice settings: perspectives and learnings from the Phase II MorningSun study

Outpatient administration of mosunetuzumab in US community practice settings: perspectives and learnings from the Phase II MorningSun study

CNS radiotherapy as bridging prior to CAR T‐cell therapy for hematologic malignancies

Introduction: Up to 80% of patients who receive CAR T-cell therapy for central nervous system lymphoma (CNSL) require bridging therapy, yet optimal regimens remain undefined. Bridging radiotherapy (BRT) is an established strategy for extracranial lymphoma that provides beneficial cytoreduction. However, BRT for CNSL (CNS-BRT) is controversial due to concerns of potential enhanced neurotoxicity. We explored the safety and response profiles for CNS-BRT prior to CAR T therapy. Methods: We identified CAR T patients with hematologic malignancy at MSKCC who received CNS-BRT, defined as treatment delivered between cell collection and infusion to targets in CNS parenchyma, leptomeninges, or epidural space. Safety was evaluated by cytokine release syndrome (CRS), immune effector associated neurotoxicity syndrome (ICANS), and immune effector cell encephalopathy (ICE) scores, as documented by primary physician. Response was evaluated within the RT field for patients with baseline measurable disease using the International Primary CNS Lymphoma Collaborative Group (IPCG), Response Assessment in Neuro-Oncology (RANO), and Response Evaluation Criteria in Lymphoma (RECIL) radiographic criteria for parenchymal, leptomeningeal, and epidural lesions, respectively. Results: 11 patients received CNS-BRT with median follow up of 10.1 months (range: 1.1–25.9). At RT, median age was 51 (25–79), median KPS was 80 (50–90), and 9/11 patients had progressive CNS disease. 8/11 patients received prior methotrexate (high dose n = 7, intrathecal n = 1) with median 39-day interval to RT (0–179). Disease was localized to the brain parenchyma (n = 6), leptomeninges (n = 2), and epidural spine (n = 3). RT targets included whole brain (n = 3), involved site (partial) brain (n = 4), and involved site spine (n = 4), with median dose 24 Gy (20–30). Patient and CAR T cell characteristics are shown in Table 1. 4/10 patients experienced ICANS (n = 1 grade (G) 1, n = 1 G2, n = 1 G3, and n = 1 G4). 8/10 patients experienced CRS (n = 2 G1, n = 5 G2, and n = 1 G3). 6/11 patients required tocilizumab and/or steroids. Patients with G3/4 ICANS had decreased baseline ICE scores of 5 and 6, respectively. Median change in lesion size prior to CAR T infusion was -43.6% (-3.1% to -74.5%) among 7 evaluable patients. Best response included 6 partial responses (PR) and 4 complete responses (CR) at median 4.2 months (0.5–10.4). There were 3 CNS treatment failures, 1 in the leptomeninges and 2 in the paraspinal/epidural space. Keywords: Aggressive B-cell non-Hodgkin lymphoma, Cellular therapies, Radiation Therapy Conflicts of interests pertinent to the abstract. R. Shouval Other remuneration: Medexus Pharmaceuticals, Inc., MyBiotics P. B. Dahi Other remuneration: Curio Science LLC, Kite Pharmaceuticals, OncLive, Targeted Oncology R. J. Lin Consultant or advisory role: Kite, A Gilead Company M. L. Palomba Other remuneration: BeiGene, Ltd., Mustang Bio, Novartis, Synthekine, Inc. M. Perales Stock ownership: NexImmune, Omeros, Orca Biosystems, Inc. Other remuneration: ADC Therapeutics, Bristol-Myers Squibb, Cidara Therapeutics, Inc., CoImmune, Inc., Equillium, Inc., Incyte, Jazz Pharmaceuticals, Karyopharm, Kite Pharmaceuticals, Merck & Co Inc., Miltenyi Biotec Incorporated, MorphoSys AG, Novartis, Partners Therapeutics Inc., VectivBio AG, Vor Biopharma Inc. G. Salles Stock ownership: Owkin, Inc. Other remuneration: AbbVie, Aptitude Health, Bayer, BeiGene, Ltd., Bio Ascend, Bristol-Myers Squibb, Celgene, Epizyme, Everest Clinical Research Corporation, GenMab, Genentech, Gilead Pharmaceutical, Incyte, Ipsen, Janssen Pharmaceuticals, Inc., Loxo Oncology, Miltenyi Biotec Incorporated, MorphoSys AG, Nordic Nanovector ASA, Novartis, Physicians' Education Resource, RAPT Therapeutics, Regeneron Pharmaceuticals, Inc., Roche, Scientific Education Support Ltd., Takeda Millennium L. Falchi Consultant or advisory role: Genmab, Abbvie, Genentech, ADC therapeutics, Astrazeneca, Seagen, Roche Research funding: Genmab, Abbvie, Roche, Genentech Educational grants: Genmab C. Grommes Other remuneration: BTG International, Ono Pharma, Roche M. Scordo Consultant or advisory role: McKinsey & Company, Angiocrine Bioscience, Inc., Omeros Corporation, Kite – A Gilead Company Honoraria: i3Health, Medscape Research funding: Angiocrine Bioscience, Inc., and Omeros Corporation J. Yahalom Other remuneration: Convergent R.N.R Ltd. B. S. Imber Other remuneration: GT Medical Technologies, Inc.

17th International Conference on Malignant Lymphoma, Palazzo dei Congressi, Lugano, Switzerland, 13 - 17 June, 2023.

Introduction: Central nervous system (CNS) involvement in patients with refractory or relapsed large B-cell lymphoma (LBCL) is associated with an extremely poor prognosis. Autologous anti-CD19 chimeric antigen receptor (CAR) T-cell therapy is an approved treatment for patients with refractory or relapsed (R/R) LBCL that has changed the prognosis of patients with chemoresistant LBCL. However, data regarding efficacy and safety of CART cell treatment in patients with active CNS involvement are limited since they are excluded from most of clinical trials. Methods: We retrospectively collected data from 75 patients with LBCL, treated with CART cells from January 2020 to January 2023 in Henri Mondor Hospital. We identified 13 patients with active CNS involvement at the time of CAR-T cell treatment decision: 12/13 had abnormal neurological examination, 8/11 had head and/or medullar MRI abnormalities consistent with lymphoma and 9/10 had detectable lymphoma cells in the cerebrospinal fluid. We compared the characteristics of the 13 patients with CNS involvement (CNS+) with 62 patients without evidence of active CNS disease (CNS-). Median age was 69 and 59 years, respectively (p = 0.05). CNS+ patients received a median of 2 previous lines of treatment versus 3 for CNS- patients (p = 0.34). Performance status prior to CART-cell injection was 2 or more in 9/13 (69%) and 11/62 (18%) p < 0.001, respectively. 5/13 (38%) CNS+ patients had high grade B-cell lymphomas versus 11/62 (18%) CNS- (p = 0.13). CAR-T-cell was axi-cel in 10/13 (77%) CNS+ patients versus 42/62 (68%) CNS– (p = 0.74). It is noteworthy that 7/13 (54%) CNS+ patients had pre-existing low-grade B-cell lymphomas versus 15/62 (24%) CNS- (p = 0.046). Results: The best overall response rate was identical in both groups: 12/13 (92%) in CNS+ patients versus 51/61 (92%) in CNS-, including 11/13 (85%) and 44/61(72%) complete metabolic response. As shown in the figure, median progression free survival and overall survival was 5.5 and 8.4 months, respectively in CNS+ patients versus 11.5 and 21 months in CNS- patients (not significant). Regarding safety, 13/13 (100%) CNS+ patients had a cytokine release syndrome (10 grade 1–2 and 3 grade 3) versus 54/62 (87%) CNS- (49 grade 1–2 and 5 grade 3–4) and 10/13 (77%) experienced ICANS (6 grade 1–2 and 4 grade 3–4) versus 28/62 (45%) CNS- (27 grade 1–2 and 1 grade 3–4) (p = 0.06 and 0.02 for grade 3–4). Transfer into an intensive care unit occurred in 4/13 (31%) CNS+ patients versus 9/62 (15%) CNS- (p = 022). Median time of hospitalization was 37 days for CNS+ patients versus 20 days for CNS- patients (p = 0.007). Six CNS+ patients died from which 5 died of progression and 1 of infection. Keywords: Aggressive B-cell non-Hodgkin lymphoma, Cellular therapies, Immunotherapy Conflicts of interests pertinent to the abstract. F. Lemonnier Consultant or advisory role: BMS, Kiowa, Miltenyi Educational grants: Gilead, Janssen, Roche L. Roulin Educational grants: Kite gilead, Novartis, Bristol myers squibb

POLATUZUMAB, BENDAMUSTINE &amp; RITUXIMAB EFFICACY IN RELAPSED/REFRACTORY TRIAL‐INELIGIBLE LARGE B CELL LYMPHOMA PATIENTS: AN AUSTRALIAN LYMPHOMA REGISTRY (LARDR) STUDY

Introduction: RRDLBCL outcomes remain poor despite autologous transplant and CAR-T therapies offering potential cure to a minority. Evidence for current therapies is mostly from phase II trials with stringent eligibility criteria. Applicability to real-world populations is poorly understood. PolaBR efficacy in RR DLBCL was shown in the landmark GO29365 study (BCT02600897; Sehn Blood Adv 2022). However, the efficacy of PolaBR in routine care RR DLBCL patients (pts) who fail to meet original study eligibility criteria is unknown. Here we report outcomes of Australian RR DLBCL pts receiving compassionate PolaBR according to their eligibility for the GO29365 trial. Methods: This was a retrospective study of RR DLBCL pts ≥18y receiving Pola ≥ BR from the Australian Lymphoma Registry (LaRDR). Data analysed included: demographics, pt demographics, disease & prior therapy details, trial eligibility criteria, outcomes and toxicity. Descriptive statistics were used to report frequency. Kaplan-Meier method and the Cox proportional hazard model were used for comparison of survival & comparisons according to prognostic factors. Results: 58 pts were identified between 2019 and 2022, median age 63.0 y, 62% were male; 86% had stage III-IV disease; 61% had R-IPI ≥3. 70% had ≥2 prior therapies (38% >3 prior lines) with most treatment lines being chemotherapy with rituximab. 74% failed ≥1 eligibility criteria of the landmark PolaBR study and 47% failed ≥2 ineligibility criteria (Table 1). Pola was given with BR in 59%, Ritux only in 24%; and single-agent in 8%. Just 27% completed all 6 planned cycles. Reasons for cessation included progressive disease 52%; bridging to other therapy 10%; death 6%; toxicity 4%. 8 pts received up to 2 subsequent lines of therapy, with 2 receiving CAR-T therapy. Overall response rate was 38% (25% CR). Median follow up was 3.2 m (range 0–31). Median overall survival was 3.9 m (95% CI 2.9–7.3 m). Median PFS was 2.5 m (95% CI 1.9–4.1 m). No difference in OS or PFS was observed for eligible versus non-eligible pts and failure of any one eligibility criteria category did not impact outcome. No difference in OS observed between pola-BR and pola-R (p = 0.32). Conclusion: While response rates were similar to other real-world studies (Northend et al. 2022; Dimou et al., 2021; Wang et al., 2022) they were lower than the registration trial. The high proportion of pts ineligible for the landmark pola-BR registration study and limited access to subsequent therapy potentially explain inferior response and survival outcomes in our cohort. Although acknowledging our modest sample size impacts the results, outcomes of novel therapies in real-world pts are likely influenced by factors outside of those related to trial eligibility such as adverse disease biology and additional comorbidites. Encore Abstract—previously submitted to EHA 2023 Keyword: aggressive B-cell non-Hodgkin lymphoma Conflicts of interests pertinent to the abstract A. Johnston Consultant or advisory role MSD, Roche, Link, Beigene, Sanofi, Eusa pharma, Novartis C. Cheah Honoraria: Roche, Janssen, Gilead, AstraZenecca, Lilly, TG therapeutics, Beigene, Novartis, Menarini, Daizai, Abbvie, Genmab. BMS Research funding: BMS, Roche, Abbvie; MSD, Lilly A. Barraclough Honoraria: Roche and Gilead M. Ku Consultant or advisory role Roche, Antengene, Genor BioPharma N. Viiala Consultant or advisory role Novartis Honoraria: Novartis T. Cochrane Consultant or advisory role Janssen Honoraria: Celgene (in 2019) Research funding: Beigene G. Chong Research funding: BMS, Merck Serono, Astra Zeneca, Pharmacyclics, Regeneron, Hutchmed, Bayer, Incyte, Amgen S. Opat Honoraria: AbbVie, Beigene, AstraZeneca, BMS, CSL Behring, Gilead, Janssen, Merck, Roche, Takeda Research funding: AbbVie, Beigene, AstraZeneca, CSL Behring, Gilead, Janssen, Merck, Pharmacytics, Roche, Takeda E. Hawkes Consultant or advisory role Roche, Merck Sharpe & Dohme, Astra Zeneca, Gilead, Antigene, Novartis, Regeneron, Janssen, Specialised Therapeutics Research funding: Roche, Bristol Myers Squibb, Merck KgA, Astra Zeneca and Merck

EXPLORING DIFFERENTIAL MUTATIONAL DISTRIBUTION BY TARGETED SEQUENCING IN A R‐CHOP TREATED COHORT OF DIFFUSE LARGE B‐CELL LYMPHOMA PATIENTS

Background: Diffuse large B-cell lymphoma (DLBCL) harbors striking clinical and molecular heterogeneity, which continues to encumber risk stratification with a consequently high rate of refractory/relapsed patients (pts). Though the genomic landscape of DLBCL has been comprehensively uncovered, the search for eligible molecular biomarkers continues. Exploratively, we set out to retrospectively evaluate differential mutational distributions in a DLBCL cohort using targeted sequencing. Patients and method: A cohort of 105 de novo DLBCL pts, uniformly treated with first-line R-CHOP, were studied. Thirty pts relapsed, of which 70% had early relapses (<2 years after completing therapy), while 30% had late relapses (≥2 years). Targeted next-generation sequencing (90 gene panel) was applied on archival paraffin-embedded diagnostic samples and, if available, first relapse samples. Results: In total, 118 samples were sequenced, each displaying a median of 12 (range 1–46) putative somatic protein-coding mutations. Germinal center B-cell (GCB) DLBCL (n = 60) displayed a differential somatic signature with enrichment of EZH2, TNFRSF14, BCL2, ACTB, SOCS1, and FAS mutations (Fisher's Exact, p < 10-4), whereas mutations in CDKN2A, PRDM1, MYD88, and CD79B were significantly enriched in non-GCB pts (p < 10-4, n = 44). Survival analysis confirmed inferior overall survival (OS) in non-GCB DLBCL (5-year OS, log-rank (Mantel-Cox), p = 0.01, hazard ratio (HR) 1.7). Pts with double-hit biology (DHB), defined as either MYC and BCL2 and/or BCL6 fluorescent in situ hybridized positive and/or with MYC and BCL2 immunohistochemical double expression (n = 32), did not display a significant mutational signature or differential OS. However, a subgroup of DHB pts characterized by mutations in MYC, PRDM1, or IRF4 (n = 15) had markedly inferior OS (5-year OS, log-rank, p = 0.0003, HR 3.34) compared to negative non-DHB pts (n = 55) or negative non-DHB/DHB pts (p = 0.0017, HR 2.7, n = 72). Noticeably, ACTB mutations were only present in non-DHB pts. The mutational distribution at diagnosis did not differ between pts with relapse and in sustained remission. However, in the relapse group, GNA13 mutation at diagnosis was more frequent in early relapses than late relapses (43% vs. 0%, Fisher’s Exact without correction, p = 0.03). The presence of GNA13 in the entire cohort showed a trend towards inferior survival. Conclusion: Differential distribution with significant mutational signatures were expectedly found in GCB versus non-GCB, but not in subgroups with DHB or relapse. Interestingly, mutations in MYC, PRDM1 or IRF4 identified a distinct subset of DHB pts with inferior survival. Furthermore, GNA13 mutations were significantly enriched in early relapse pts. These preliminary findings call for validation of GNA13 as a potential marker of early relapse as well as the prognostic value of MYC, PRDM1 and IRF4 mutations in DHB DLBCL. The research was funded by: The Danish Cancer Society and The Vissing Foundation Keywords: aggressive B-cell non-Hodgkin lymphoma, genomics, epigenomics, and other -omics, tumor biology and heterogeneity Conflicts of interests pertinent to the abstract T. S. Larsen Consultant or advisory role Roche, Gilead, Novartis, Celgene/BMS Research funding: Genentech

Neurotoxicity in patients with CNS lymphomas treated with CAR‐T cell therapy. A LOC network study

Introduction: CAR-T cell therapy represents one of the major progress of the last years in aggressive B-cell lymphomas. Its use in central nervous system (CNS) lymphomas has been limited due to the fear of neurotoxicity but several recent studies have showed promising efficacy in this setting. The aim of this study was to focus on neurotoxicity in CNS lymphoma patients treated with CAR-T cells. Methods: Patients with isolated CNS relapse of DLBCL treated with commercial CAR-T cells at Pitié-Salpêtrière hospital were retrospectively selected. We considered only neurological deterioration for which other causes than CAR-T cell toxicity had been reasonably ruled out. Results: Thirty patients (median age: 65, 17 women, 19 primary, 11 secondary CNS lymphomas, median of 3 previous lines) received CAR-T cells (Tisa-cel: N = 23, axi-cel, N = 7) between May 2020 and December 2022. At the time of CAR-T, 15 (50%) had stable or progressive disease, median Karnofsky Performance Status (KPS) was 70, median Montreal Cognitive Assessment (MoCA) score was 22 and median immune effector cell-associated encephalopathy (ICE) score was 10. Twelve (40%) patients didn’t experience any neurotoxicity after CAR-T, whereas 9 (30%), 3 (10%), 2 (7%), 4 (13%) patients experienced grade 1, 2, 3 or 4 toxicity according to ASTCT classification. The signs of neurotoxicity began at a median of 5 days after CAR-T. The most common symptoms were cognitive disorders (N = 18), motor deficit (N = 4), balance disorders (N = 8), consciousness disorders (N = 5), seizures (N = 3) and movement disorders (N = 3). Among cognitive symptoms, there was predominantly a worsening of pre-existing symptoms regarding memory impairment (12/15 patients) or dysexecutive syndrome (11/13), while dysgraphia or dyscalculia were most frequently new symptoms (in 14/15 and 7/11 patients). Brain MRI showed pseudo-progression in 4 cases. On lumbar puncture, median IL-6 level and median cellularity were higher in patients with grade 2 to 4 neurotoxicity compared to other patients (243 vs. 41 pg/ml, 15 vs. 3 cells/mm3). We found no association between risk of neurotoxicity and age, gender, pre-CART KPS, MoCA or ICE score, primary vs. secondary CNS lymphoma or type of CAR-T. Twelve patients (40%) received steroids, for a median of 10 days, leading to an improvement in a median of 5 days; one received anakinra. Median duration with neurological impairment was 13 days, but was >3 months in 3 patients, including one who finally died from neurotoxicity. Conclusions: The majority of CNS lymphoma patients didn’t experience severe neurotoxicity following CAR-T cells, so that this treatment shouldn’t be contraindicated in this population. However, the percentage of severe and prolonged neurotoxicity is probably higher than in systemic lymphomas and a close neurological follow-up is warranted in these complex situations. Further studies are needed to better predict severe neurotoxicity. Keyword: Cellular therapies Conflicts of interests pertinent to the abstract. S. Choquet Consultant or advisory role: Kite-Gilead, Novartis

17th International Conference on Malignant Lymphoma, Palazzo dei Congressi, Lugano, Switzerland, 13 - 17 June, 2023.

Introduction: Pre-treatment PET/CT scans have not yet been incorporated into risk stratification models despite being the imaging modality of choice in DLBCL. Deep learning computer algorithms have consistently demonstrated the ability to analyze imaging data and identify features that are not readily apparent to the human eye. Therefore, to assess the prognostic performance of pre-treatment PET/CT scans in patients with DLBCL, we compared automatically extracted radiomics features using a convolutional neural network with a standard prognosticating tool (NCCN-IPI). Methods: Native DICOM images from FDG PET/CT scans of newly diagnosed DLBCL patients were preprocessed for regularity and then segmented using the nnU-Net architecture with an external lymphoma-specific model. Feature extraction and SUV characterization were accomplished with PyRadiomics and NiBabel. Our computational method included no manual segmentation correction. Individual radiomics features (n = 115) were evaluated for association with event free survival (EFS) via univariate Cox regression analysis and by Kaplan Meier log rank testing of upper and lower feature quartiles. Additionally, Spearman and Pearson correlation matrices were used to guide feature selection while minimizing collinearity. We then assessed the association of the highest scoring radiomics features with EFS. Results: Radiomics features were automatically extracted from a cohort of 713 newly diagnosed DLBCL patients with pre-treatment PET/CT scans treated at Mayo Clinic between 2003 and 2015 and followed through 2023. Median age at diagnosis was 64 years (range 18–93), 41% were females. NCCN-IPI composition and outcomes of our cohort was comparable to the previously published NCCN cohort, with patient distribution and 5-year OS as follows: Low (11%, 5-y OS 89%), Low-intermediate (42%, 5-y OS 72%), High-intermediate (38%, 5-y OS 53%), High (9%, 5-y OS 25%). Log rank testing found numerous radiomics features were associated with EFS including least axis length (LAL) (HR: 2.83, 95% CI: 2.08–3.84, p < 0.005, Figure A) and volume (HR: 2.47, 95% CI: 1.84–3.01, p < 0.005, Figure B). As a reference, NCCN-IPI univariate Cox regression analysis of EFS produced a Harrell’s C-statistic (c) of 0.633. Single radiomics features of sphericity, volume, surface area, and least axis length individually produced unadjusted c-statistics of 0.624, 0.629, 0.636 and 0.638, respectively. Combinations of radiomics features (surface area + least axis length) demonstrated cumulative benefit (c = 0.642). Keywords: Aggressive B-cell non-Hodgkin lymphoma, PET-CT, Risk Models Conflicts of interests pertinent to the abstract. T. M Habermann Consultant or advisory role: Data Monitoring Committee: Seagen, Tess Therapeutics, Eli Lilly & Co. Scientific Advisory Board: Morpohsys, Incyte, Biegene, Loxo Oncology. No personal compensation is received for these activities, any compensation is received by my institution. Research funding: Genentech, Sorrento, BMS

Brincidofovir induces potent anti‐tumor activity in MYC‐driven Natural Killer/T‐cell Lymphoma with loss of transcriptional repressor TLE1

Introduction: Natural killer/T-cell lymphoma (NKTCL) is an aggressive Epstein-Barr virus (EBV)-associated malignancy which is prevalent in Asian countries. Brincidofovir (BCV), a lipid conjugated form of cidofovir, is a biologically-active acyclic nucleoside phosphonate recently shown to exhibit both antiviral and antitumor properties. Methods: We investigated BCV in NKTCL cell-lines (n = 11) and mouse xenograft models. Whole exome sequencing, bulk RNAseq and single cell RNAseq (scRNAseq) were employed to examine mechanisms of action, and validated using orthogonal assays. Results: BCV inhibited viability in all NKTCL cell-lines in a dose- and time-dependent manner. Highest sensitivity was demonstrated in four cell-lines KAI-3, NK-S1, NK-92 and KHYG-1 (IC50 36.0 to 303.6 ng/ml). Intraperitoneal BCV (40 mg/kg, 2X per week) inhibited tumor growth in NOD/SCID mice NK-S1 xenografts, compared with vehicle alone (p = 0.0005, two-tailed t-test). Whole exome sequencing of the cell-lines revealed widespread mutations in the JAK/STAT and DNA repair pathways, with no clear correlation observed with BCV sensitivity. RNAseq and Hallmark gene set enrichment analysis showed that MYC target pathways (FDR q < 0.001) were prominently upregulated in the four sensitive cell-lines compared to the rest. RNAseq of BCV-treated cell-lines (KAI-3 and NK-S1) revealed striking downregulation of MYC target pathways. scRNAseq revealed distinct temporal cell states evoked by BCV, including appearance of cell clusters enriched for p53 and apoptosis pathways, cell cycle and DNA repair pathways, as well as type I/II interferon and cytokine signaling. Western blot and quantitative PCR showed that markers of replication stress, DNA damage and STING signaling were potently upregulated, implicating an immunogenic form of cell death. Notably, TLE1, a known transcriptional repressor of the MYC oncogene, was the topmost downregulated gene (log2FoldChange -7.39, adjusted p = 3.51E-31) in the four BCV-sensitive cell-lines on RNAseq. This finding was verified on qPCR (p = 0.0061, Mann-Whitney test) and Western blot. In keeping with this result, RNAseq on NKTCL patient samples (n = 36) showed that TLE1-low tumors were enriched for MYC target pathways, which conferred worse progression-free survival (HR 3.44, 95% CI: 1.23–10.49, p = 0.0301). Conclusions: Taken together, these results suggest that BCV may play a novel role in the treatment of MYC-driven NKTCL. Loss of TLE1, a putative predictive biomarker, implies that BCV may favour patients in this poor prognostic subgroup. The research was funded by: Symbio Pharmaceuticals, Tanoto Foundation Professorship in Medical Oncology, New Century Foundation Limited, Ling Foundation, Singapore Ministry of Health’s National Medical Research Council Transition Award (TA21jun-0005), Research Training Fellowship Seed Fund (SEEDFD21jun-0002), Large Collaborative Grant (OFLCG18May-0028), and Collaborative Centre Grant (TETRAD II). Keywords: Diagnostic and Prognostic Biomarkers, Extranodal non-Hodgkin lymphoma, Molecular Targeted Therapies Conflicts of interests pertinent to the abstract. J. Y. Chan Consultant or advisory role: Symbio Pharmaceuticals Research funding: Symbio Pharmaceuticals M. Hazama Employment or leadership position: SymBio Pharmaceuticals Limited K. Fukushima Employment or leadership position: SymBio Pharmaceuticals Limited C. K. Ong Research funding: SymBio Pharmaceuticals Limited

CART‐SIE REAL LIFE STUDY: PRIMARY MEDIASTINAL B‐CELL LYMPHOMA (PMBCL) HAVE A SUPERIOR OUTCOME COMPARED TO LARGE B‐CELL LYMPHOMA (LBCL) TREATED WITH AXICABTAGENE CILOLEUCEL

Introduction: In Italy, axicabtagene ciloleucel (axi-cel) is commercially available for the treatment of LBCL, including diffuse large B-cell lymphoma (DLBCL-NOS), high grade B-cell lymphoma (HGBCL), transformed follicular lymphoma (tFL), and PMBCL patients, relapsed/refractory (R/R) after at least two prior treatments. Methods: The CART-SIE is an ongoing prospective and retrospective study collecting data on the outcome of all consecutive lymphoma patients treated with CAR-T cells. The aim of this analysis was to compare the outcome of PMBCL and LBCL treated with axi-cel in the Italian real life. Results: From 2019 to 2022, 444 patients were infused. Axi-cel was administered in 192 patients: 57 PMBCL and 135 LBCL, including DLBCL-NOS (85), HGBCL (28) and tFL (22), respectively. The clinical characteristics for PMBCL versus LBCL showed: median age 35 versus 56 (p = 0.0001), bulky 33/57 (58%) versus 47/135 (35%) (p = 0.0035), limited stage 35/57 (61%) versus 41/135 (31%) (p = 0.0001), respectively. Median follow-up time for infused patients was 10.99 months (IQR 4.18, 18.03). The Overall Response Rate (ORR, complete CR + partial PR) at 30-days after the infusion was 44/57 (77%) with 30 (53%) CR in PMBCL, and 97/135 (72%) with 67 (50%) CR in LBCL, (p = 0.4206). The 12-months Overall Survival (OS) was 89% (95% CI: 81–98) in PMBCL versus 70% (95% CI: 62–80) in LBCL (log-rank p = 0.0016); by different histology subtypes, the 12-months OS was 89% (95% CI: 81–98) in PMBCL versus 74% (95% CI: 63–86) in DLBCL-NOS, 58% (95% CI: 41–81) in HGBCL, 76% (95% CI: 58–100) in tFL (log-rank p = 0.0013). The 12-months PFS was 65% (95% CI: 53–80) in PMBCL versus 47% (95% CI: 39–57) in LBCL (log-rank p = 0.0160); by different histology subtypes, the 12-months PFS was 65% (95% CI: 53–80) in PMBCL versus 40% (95% CI: 30–54) in DLBCL-NOS, 51% (95% CI: 35–75) in HGBCL, 65% (95% CI: 47–90) in tFL (log-rank p = 0.0420). All grades CRS was observed in 49/57 (86%) PMBCL and 118/135 (87%) LBCL patients, with 9 (16%) and 12 (9%) severe (grade 3–4) CRS, respectively; all grades ICANS were reported in 25 (44%) PMBCL patients and in 46 (34%) LBCL, with 12 (21%) and 14 (10%) severe (grade 3–4) ICANS, respectively. Tocilizumab was administered in 41 (72%) PMBCL and in 90 (67%) LBCL; steroids in 20 (35%) PMBCL and in 36 (27%) LBCL patients. Twelve (21%) PMBCL and 15 (11%) LBCL patients were admitted in the intensive care unit. Treatment related mortality was reported in 3 (5%) PMBCL and 3 (2%) LBCL patients. In a multivariable model with all clinically important and unbalanced variables, PMBCL maintained its significantly superior outcome as compared to LBCL, for OS and for PFS. Conclusions: CART-SIE is the first real-life study comparing the prognosis of patients affected by R/R PMBCL and LBCL treated with axi-cel. PMBCL patients had a superior OS and PFS compared to LBCL, with a similar incidence of CRS and ICANS. Encore Abstract—previously submitted to EHA 2023 Keywords: aggressive B-cell non-Hodgkin lymphoma, cellular therapies Conflicts of interests pertinent to the abstract A. Chiappella Consultant or advisory role: Celgene-BMS, Gilead-Sciences, Ideogen, Janssen, Roche, SecuraBIO, Takeda Other remuneration: Lecture fees/Educational activities: Astrazeneca, Celgene-BMS, Gilead-Sciences, Incyte, Janssen-Cilag, Novartis, Roche, Takeda

COMBINED USE OF MINIMAL RESIDUAL DISEASE MONITORING AND FDG‐PET FOR OUTCOME PREDICTION IN FOLLICULAR LYMPHOMA: RESULTS FROM THE FONDAZIONE ITALIANA LINFOMI (FIL) FOLL12 TRIAL

Introduction: In follicular lymphoma (FL), FDG-PET is routinely employed to evaluate response at the end of induction (EoI), while minimal residual disease (MRD) analysis is highly reliable in predicting relapse over the entire disease history. Nonetheless, scant data are available describing the integration of these powerful prognostic tools for response evaluation in FL. This issue was investigated in the phase III FIL “FOLL12” trial [Luminari, JCO 2022]. Methods: Only patients with an available molecular marker for MRD and centrally reviewed EoI PET were included. MRD was systematically assessed by RQ-PCR with BCL2::IGH consensus primers in peripheral blood (PB) and bone marrow (BM), as previously reported with inferior follow-up [Ladetto ASH 2021]. PET scans were classified according to Deauville score (DS) criteria: DS1–3 was negative and DS4–5 positive. Results: Overall, 394 patients out of 780 were included (51%), as expected based on the MRD marker availability. These patients had a slightly better outcome than excluded cases (CR rate 82% vs. 73%, p = 0.003, 5y PFS 66% vs. 61%, p = 0.046). At EoI, both BM MRD and PET positivity were independent predictors of poor PFS in multivariate analysis (HR 1.66, CI: 1.01–2.71 and HR 2.03, CI: 1.30–3.18). The 68 discordant cases (i.e., MRD+/PET− or MRD−/PET+) showed an intermediate outcome (PFS HR 1.93, CI: 1.28–2.92) between the 314 double negative (reference) and the 10 double positive ones (HR 6.22, CI: 2.99–12.9), Figure 1A. Moreover, both EoI PET+ and the persistence/reappearance of MRD positivity in BM during the 18 months of rituximab maintenance/observation were independently associated to a higher risk of POD24 (HR 5.61, CI: 2.59–12.1, and HR 2.37, CI: 1.15–4.84, respectively). On the other hand, MRD kinetic analysis by non-invasive PB sampling during the rituximab maintenance/observation period substantially updated the risk status over PET results. Indeed, the marginal PFS HR for an MRD+ after an EoI PET negative result increased from 1.36 (CI: 0.47–3.96) at 6 months, to 2.09 (CI: 1.01–4.18) at 12 months, up to 3.60 (CI: 2.30–5.64) at 24 months (Figure 1B, blue curve). This means that patients scoring PET- at EoI but showing a persistent or reappearing MRD+ signal during the following 24 months had a dismal PFS, superimposable to that of PET+ patients (Figure 1C). Accordingly, in landmark multivariate analysis PB MRD+ either at 12 or 24 months predicted adverse PFS (HR 3.79, CI: 1.60–8.96 and HR 5.21, CI: 1.88–14.4, respectively), independently from EoI PET result. Keywords: indolent non-Hodgkin lymphoma, minimal residual disease, PET-CT Conflicts of interests pertinent to the abstract S. Ferrero Consultant or advisory role: Janssen, EUSA Pharma, Abbvie, Incyte, Clinigen, Sandoz, Italfarmaco Honoraria: Janssen, EUSA Pharma, Servier, Gentili Research funding: Morphosys, Janssen, Gilead, Beigene Educational grants: Takeda, Janssen, EUSA Pharma

SEVERE HEMATOLOGICAL TOXICITY FOLLOWING CD19 CAR‐T FOR RELAPSED/REFRACTORY LBCL IS ASSOCIATED WITH SUPPRESSIVE IMMUNE DYSREGULATION AND LIMITED CAR‐T EXPANSION

Background: Hematological toxicity represents the most frequent high-grade toxicity of CD19 CAR-T, but remains poorly understood. We recently proposed a classification system for CAR-T-related hematotoxicity, defining three unique phenotypes of neutrophil recovery: quick [“Q”] versus intermittent [“I”] versus aplastic [“A”]. Quick: sustained neutrophil recovery without a second dip below an ANC <1000/µL. Intermittent: neutrophil recovery (ANC > 1500/µL) followed by a second dip with an ANC < 1000/µL after day 21. Aplastic: continuous severe neutropenia (ANC < 500/µL) ≥14 days. Multivariable binary logistic regression was applied to analyze clinical metadata. CAR T-cell expansion dynamics were studied during the first 4 months post-CAR-T infusion. The plasma proteome was explored in 58 patients across four time points (day 0, 4, 14, 28) using a 92-protein multiplex proximity extension assay (Olink Bioscience). Progression-free (PFS) and overall survival (OS) were studied via Kaplan-Meier estimates. Results: The distribution of phenotypes was 18%, 42%, and 40% (A vs. I vs. Q). As expected, ‘aplastic’ patients displayed prolonged severe neutropenia (A vs. I vs. Q: 28 vs. 10 vs. 5 days, p < 0.001) and a higher rate of severe infections (40% vs. 22% vs. 18%). On multivariable regression of baseline risk factors (n = 344), the aplastic phenotype was independently associated with the presence of BM infiltration (p = 0.004), low ANC (p = 0.002), and increased ferritin (p = 0.039). When comparing CAR-T expansion among phenotypes, ‘intermittent’ patients displayed the greatest CAR T-cell expansion over time (Figure 1A). Conversely, ‘aplastic’ patients displayed low expansion with an unfavorable relationship between CAR-T expansion and baseline tumor burden (Figure 1B). Serum proteomics revealed higher markers of T-cell suppression, endothelial dysfunction, inflammatory cytokines, and macrophage activation in the ‘aplastic’ phenotype group (Figure 1C). Notably, both PFS and OS was poor in the ’aplastic’patients (1-yr PFS 26%, 1-yr OS 46%). On the other hand, the ‘intermittent’ phenotype, characterized by recurrent neutrophil dips, was associated with superior survival outcomes (1-yr PFS 51%, 1-yr OS 46%). Keywords: aggressive B-cell non-Hodgkin lymphoma, cellular therapies, basic and translational science – Basic and Translational Science - Other Conflicts of interests pertinent to the abstract K. Rejeski Consultant or advisory role: BMS/CELGENE Honoraria: Novartis, BMS/CELGENE Research funding: Kite/Gilead Travel grants: Kite/Gilead

17th International Conference on Malignant Lymphoma, Palazzo dei Congressi, Lugano, Switzerland, 13 - 17 June, 2023.

Off-the-shelf allogeneic T-cell therapies face the major challenges of graft-versus-host disease (GVHD) and graft rejection mediated by host and recipient alloreactive T cells, respectively. To address GVHD, we are using Epstein-Barr Virus-specific T cells (EBVST), which are virus specific rather than allo-specific and have not produced GVHD in over 300 allogeneic recipients. To prevent graft rejection, we modified the EBVST with a chimeric antigen receptor (CAR) targeting CD30, an antigen that is upregulated on allo-activated T-cells, which will consequently become targets for CD30.CAR EBVST. Hence, CD30.CAR EBVST can kill both CD30+ lymphoma cells and alloreactive T cells through their CAR, and may be boosted in vivo in EBV+ recipients via their native TCR. We are evaluating this approach in a phase 1 trial (NCT04288726) in patients with CD30+ lymphoma. We generated a bank of 7 CD30.CAR EBVST products by stimulating PBMC from healthy donors with overlapping EBV peptide mixtures followed by retroviral transduction with a 2nd generation, CD28-containing CD30.CAR. We have treated 16 patients (median age 36, range 22–53) with relapsed or refractory HL. Patients had undergone a median of 5 (range 3–7) prior lines of treatment. Escalating doses of 4 × 107 − 8 × 108 (DL1–4) CD30.CAR EBVST were infused after lymphodepletion. The frequency of CD30.CAR EBVST was measured by real time qPCR for the transgene in blood. Changes in the frequency of T-cells responding to EBV or tumor-associated antigens (epitope spreading) were measured by IFNɣ ELISpots. Clinical responses were assessed per Lugano criteria by PET/CT scans performed 4–8 wks post infusion. CD30.CAR EBVST were well tolerated, with no GVHD and only two patients having reversible grade 4 cytopenia. Five patients at DL3–4 had grade 1 cytokine release syndrome (CRS), but all resolved without treatment. Of the 16 patients treated, 6 had partial responses (PR) and 6/13 patients at DL2–4 had complete responses (CR), giving an overall objective response rate (ORR) of 75%. Despite these remarkable responses, qPCR for the CD30.CAR transgene showed near background levels by wk 1 post infusion. Although this could mean that CAR-T are quickly eliminated by alloreactive T-cells, additional infusions from the same donor product into the same patient can be associated with response (Figure 1); an alloreactive response would be anticipated to be amplified after each infusion and preclude additional responses. We are therefore analyzing tumor biopsy samples to determine the presence of CD30.CAR EBVST at tumor sites and characterize their phenotype for functionality. The research was funded by: Leukemia and Lymphoma Society SCOR (Heslop) and Tessa Therapeutics (Rooney/Ramos) through a grant to Baylor College of Medicine. Keywords: cellular therapies, Hodgkin lymphoma Conflicts of interests pertinent to the abstract C. A. Ramos Consultant or advisory role: Novartis, Genentech, CRISPR Therapeutics Research funding: Tessa Therapeutics, Athenex Therapeutics Other remuneration: Royalties: Tessa Therapeutics D. H. Quach Research funding: Tessa Therapeutics P. D. Lulla Research funding: Marker Therapeutics, Allovir R. H. Rouce Consultant or advisory role: Pfizer, Novartis Honoraria: Novartis, Medline Plus Research funding: Tessa Therapeutics B. J. Grilley Consultant or advisory role: Allovir, Marker Therapeutics, Tessa Therapeutics, Lokon Pharma, March Bio and Proxima Clinical Research Stock ownership: Allovir, QBRegulatory LLC N. Lapteva Consultant or advisory role: Tessa Therapeutics Research funding: Tessa Therapeutics M. K. Brenner Employment or leadership position: Founder Member Marker Therapeutics Consultant or advisory role: Tessa Therapeutics, Marker Therapeutics, Allogene, Walking Fish, Athenex, Turnstone Biologics, Posedia, Tscan, Bluebird Bio, Adaptimmune Therapeutics, Adintus, Onkimure, Triumvira Immunologics, Bellicum Pharmaceuticals, Memgen LLC, Brooklyn Immunotherapeutics, Coya, Astrazeneca Pharmaceuticals Stock ownership: Allovir, Marker Therapeutics, Tessa Therapeutics, Turnstone, Bluebird Bio, Allogene, Walking Fish, AlloVir, Tessa, Tscan Other remuneration: Royalties: Takeda, Bellicum, Marker Therapeutics H. E. Heslop Consultant or advisory role: Gilead Biosciences, Novartis, Tessa Therapeutics, Marker Therapeutics, Kiadis, PACT Pharma, Mesoblast, Ankyra Therapeutics Stock ownership: Allovir, Marker Therapeutics, Fresh Wind Biotechnologies, CoRegen Inc. Research funding: Tessa Therapeutics, Athenex Therapeutics C. M. Rooney Consultant or advisory role: Tessa Therapeutics, Marker Therapeutics, Cell Genix Stock ownership: Allovir, Marker Therapeutics Research funding: Tessa Therapeutics Other remuneration: Royalties: Takeda, Marker, Allovir, Bellicum

17th International Conference on Malignant Lymphoma, Palazzo dei Congressi, Lugano, Switzerland, 13 - 17 June, 2023.

Background: One-year fixed-duration venetoclax-obinutuzumab (Ven-Obi) is a standard-of-care for patients (pts) with previously untreated chronic lymphocytic leukemia (CLL). Due to its ongoing follow-up, the CLL14 study provides unique insights into long-term outcomes of pts after Ven-Obi therapy. Methods: Pts with previously untreated CLL and coexisting conditions were randomized 1:1 to Ven-Obi or chlorambucil-obinutuzumab (Clb-Obi). Primary endpoint was investigator-assessed progression-free survival (PFS). Secondary endpoints included safety, rates of minimal residual disease (MRD), time to next treatment (TTNT) and overall survival (OS). Results: Of 432 enrolled pts, 216 were randomly assigned to Ven-Obi, 216 to Clb-Obi. At a median follow-up of 76.4 months (interquartile range 52.5–80.5), PFS remained superior for Ven-Obi compared to Clb-Obi (median 76.2 vs. 36.4 months; HR 0.40 [95% CI 0.31–0.52], p < 0.0001). Progressive disease (PD) occurred in 67 cases in the Ven-Obi arm with 39 second-line treatments, and in 141 cases in the Clb-Obi arm (with 103 second-line treatments). TTNT was significantly longer after Ven-Obi (6-year TTNT 65.2% vs. 37.1%; HR 0.44, 95% CI 0.33–0.58, p < 0.0001). In both arms, the most frequent second-line treatments were BTK inhibitors (61.5% in the Ven-Obi arm, 55.4% in the Clb-Obi arm). The PFS and TTNT difference between the two arms was maintained across all risk groups, including pts with TP53 mutation/deletion (median PFS 51.9 vs. 20.8 months; median TTNT 57.3 vs. 29.0 months) and unmutated IGHV status (median PFS 64.8 vs. 26.9 months; median TTNT 85.4 vs. 40.6 months). Multivariate analysis identified TP53 deletion/mutation, unmutated IGHV and lymph node size ≥5 cm as independent negative prognostic factors for PFS in pts treated with Ven-Obi. Five years after treatment completion, 17 (7.9% of the intention-to-treat population) pts in the Ven-Obi arm still had uMRD (<10−4 by NGS in peripheral blood), 22 (10.2%) had low (L)-MRD (≥10-4 and <10-2) and 23 (10.6%) high (H)-MRD (≥10-2), compared to 4 (1.9%) uMRD, 9 (4.2%) L-MRD and 18 (8.3%) H-MRD in the Clb-Obi arm. Overall, 48 deaths were reported in the Ven-Obi arm (9 PD related) and 70 in the Clb-Obi arm (26 PD related); 6-year-OS rate was 78.7% in the Ven-Obi and 69.2% in the Clb-Obi arm (HR 0.69 [0.48–1.01], p = 0.052). Second primary malignancies were reported in 30 pts in the Ven-Obi and 18 in the Clb-Obi arm; cumulative incidences 6 years after randomization were 14.2% and 8.5%, respectively (p = 0.071). No new safety signals were observed. Encore Abstract - previously submitted to EHA 2023 The research was funded by: Roche, AbbVie Keywords: chronic lymphocytic leukemia (CLL), combination therapies Conflicts of interests pertinent to the abstract O. Al-Sawaf Consultant or advisory role: AbbVie, Ascentage, AstraZeneca, BeiGene, Eli Lilly, Gilead, Janssen, Roche Honoraria: AbbVie, Adaptive, AstraZeneca, BeiGene, Eli Lilly, Gilead, Janssen, Roche Research funding: AbbVie, BeiGene, Janssen, Roche Educational grants: AbbVie, AstraZeneca, Janssen, Gilead, Roche

17th International Conference on Malignant Lymphoma, Palazzo dei Congressi, Lugano, Switzerland, 13 - 17 June, 2023.

Introduction: The prognosis of R/R PTCLs is very poor. Selinexor is an oral, first in class, potent selective inhibitor of nuclear exportin, that shown promising overall response rate (ORR) and complete response (CR) in a phase I study of selinexor in combination with high-dose dexamethasone, ifosfamide, carboplatin and etoposide in R/R PTCLs, Tang et al (Haematologica 2021). These results are very preliminary and need to be confirmed; for this reason, we designed the PTCL S-IDE study (EudraCT number 2021-006229-23). Methods: S-IDE is a phase II multicenter pilot study of Selinexor in combination with Ifosfamide, Etoposide and Dexamethasone in patients with R/R PTCLs. We decided to omit carboplatin in order to reduce nausea and hematologic toxicity, in addition the activity of carboplatin in PTCL is uncertain. Key inclusion criteria are: age 18–75 years, R/R histologically confirmed PTCL (PTCL-NOS, angioimmunoblastic T cell lymphoma - AITL, anaplastic large cell ALK negative—ALK neg, T-helper follicular—TFH) after at least one course of anthracycline containing regimen chemotherapy (including or not high dose chemotherapy and stem cell transplantation - SCT), PS ECOG ≤2, adequate organ function. All patients will receive intravenous S-IDE on a 21-day cycle: Selinexor (40 mg on day 3, 5 and 7); Ifosfamide 5 g/mq on day 2; Etoposide 100 mg/mq on days 1–3; Dexamethasone 20 mg/day on days 3–7. Patient in CR at the end of the 4 courses receive a maintenance with selinexor (selinexor 60 mg weekly, until progression or unacceptable toxicity) or proceed to allo-SCT or auto-SCT according to donor availability, patient age and comorbidities. The primary endpoint is ORR at the end of 4 courses of S-IDE; the secondary endpoints are duration of response, 18-months PFS and OS, treatment related mortality, CR by histotypes, rate of patients able to undergo SCT, and adverse events. Exploratory biological analyses are ORR in subgroups based on GATA3 and TBX21 expression; loss of tumor suppressor genes on the CDKN2A/B-TP3 axis and PTEN-PI3K pathways as well as genetic gains and amplification of STAT3 and MYC; the presence of mutations described as associated with a poor prognosis, including CD28 mutations in AITL; TP63 rearrangement, loss of TP53, and loss of PRDM1 in ALK− ALCL; GATA3 , TP53, and/or CDKN2A in ALK− ALCL; and alterations in histone methyltransferase genes KMT2A, KMT2B, or KDM6A and FAT1 in PTCL-NOS; XPO1 expression; circulating tumor DNA (ctDNA). The sample size is 30 patients, with enrollment 18 months in 9 Italian centers. The sample size calculation refers to the primary endpoint; a sample size of 30 patients will allow to achieve a statistical power of more than 90% (94%) to test an increase of 30% of ORR (from 50% under null hypothesis to 80% under the alternative one) using a two-sided one sample binomial test with alpha =5%. The accrual is ongoing; at the end of February 2023, 2 patients have been enrolled. Keywords: aggressive T-cell non-Hodgkin lymphoma, combination therapies, ongoing trials Conflicts of interests pertinent to the abstract. A. Chiappella Consultant or advisory role Celgene-BMS, Gilead-Sciences, Ideogen, Janssen, Roche, SecuraBIO, Takeda Other remuneration: Lecture fees/Educational activities: Astrazeneca, Celgene-BMS, Gilead-Sciences, Incyte, Janssen-Cilag, Novartis, Roche, Takeda