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Follicular lymphoma (FL) is the second most common form of B cell lymphoma and generally presents as an indolent and relatively slow-growing tumor. However, most FLs are incurable with a shortening of subsequent responses. Therefore, novel and more effective treatments are desperately needed. Tazemetostat is a first-in-class, selective, oral inhibitor of EZH2, a lysine methyltransferase that is mutated in about 25% of FL. Tazemetostat has been recently approved for relapsed/refractory FL after two or more lines of therapy in the presence of an EZH2 mutation or independent of an EZH2 mutation in the absence of other options.Here, the authors provide a review focusing on the molecular mechanisms of EZH2, clinical development of tazemetostat and other EZH2 inhibitors (EZH2i), as single-agent therapy and in combinatorial regimens. Finally, they provide a futuristic look at therapeutic approaches for this disease.Tazemetostat monotherapy showed clinically meaningful and durable responses with a favorable toxicity profile, especially in EZH2 mutant lymphoma. Future studies should explore mechanism-based combinatorial regimens to maximize and prolong the anti-lymphoma effect.

Despite a characteristic indolent course, a substantial subset of follicular lymphoma (FL) patients has an early relapse with a poor outcome. Cells in the microenvironment may be a key contributor to treatment failure. We used a discovery and validation study design to identify microenvironmental determinants of early failure and then integrated these results into the FLIPI. In total, 496 newly diagnosed FL grade 1–3 A patients who were prospectively enrolled into the MER cohort from 2002 to 2012 were evaluated. Tissue microarrays were stained for CD4, CD8, FOXP3, CD32b, CD14, CD68, CD70, SIRP-α, TIM3, PD-1, and PD-L1. Early failure was defined as failing to achieve event-free survival at 24 months (EFS24) in immunochemotherapy-treated patients and EFS12 in all others. CyTOF and CODEX analysis were performed to characterize intratumoral immunophenotypes. Lack of intrafollicular CD4 expression was the only predictor of early failure that replicated with a pooled OR 2.37 (95%CI 1.48–3.79). We next developed a bio-clinical risk model (BioFLIPI), where lack of CD4 intrafollicular expression moved patients up one FLIPI risk group, adding a new fourth high-risk group. Compared with BioFLIPI score of 1, patients with a score of 2 (OR 2.17; 95% CI 1.08–4.69), 3 (OR 3.53; 95% CI 1.78–7.54), and 4 (OR 8.92; 95% CI 4.00–21.1) had increasing risk of early failure. The favorable intrafollicular CD4 T cells were identified as activated central memory T cells, whose prognostic value was independent from genetic features. In conclusion, lack of intrafollicular CD4 expression predicts early failure in FL and combined with FLIPI improves identification of high-risk patients; however, independent validation is warranted.

Summary Background Despite advances in the treatment of Hodgkin lymphoma with the introduction of PET-adapted regimens, practical challenges prevent more widespread use of these approaches. The ECHELON-1 study assessed the safety and efficacy of front-line A+AVD (brentuximab vedotin, doxorubicin, vinblastine, and dacarbazine) versus ABVD (doxorubicin, bleomycin, vinblastine, and dacarbazine) in patients with stage III or IV classical Hodgkin lymphoma. The primary analysis showed improved modified progression-free survival with A+AVD. We present an updated analysis of ECHELON-1 at 5 years, an important landmark for this patient population. Methods ECHELON-1 was an international, open-label, randomised, phase 3 trial done at 218 clinical sites, including hospitals, cancer centres, and community clinics, in 21 countries. Previously untreated patients (≥18 years with an Eastern Cooperative Oncology Group performance status of ≤2) with stage III or IV classical Hodgkin lymphoma were randomly assigned (1:1) to receive A+AVD (brentuximab vedotin, 1·2 mg/kg of bodyweight, doxorubicin 25 mg/m2 of body surface area, vinblastine 6 mg/m2, and dacarbazine 375 mg/m2) or ABVD (doxorubicin 25 mg/m2, bleomycin 10 U/m2, vinblastine 6 mg/m2, and dacarbazine 375 mg/m2) intravenously on days 1 and 15 of each 28-day cycle for up to six cycles. Stratification factors included region (Americas vs Europe vs Asia) and International Prognostic Score risk group (low, intermediate, or high risk). The primary endpoint was modified progression-free survival; this 5-year update includes analysis of progression-free survival as per investigator assessment in the intention-to-treat population, which was an exploratory endpoint, although the 5-year analysis was not prespecified in the protocol. This trial is registered with ClinicalTrials.gov ( NCT01712490 ) and EudraCT (2011-005450-60), and is ongoing. Findings Between Nov 19, 2012, and Jan 13, 2016, 1334 patients were randomly assigned to receive A+AVD (n=664) or ABVD (n=670). At a median follow-up of 60·9 months (IQR 52·2–67·3), 5-year progression-free survival was 82·2% (95% CI 79·0–85·0) with A+AVD and 75·3% (71·7–78·5) with ABVD (hazard ratio [HR] 0·68 [95% CI 0·53–0·87]; p=0·0017). Among PET-2-negative patients, 5-year progression-free survival was higher with A+AVD than with ABVD (84·9% [95% CI 81·7–87·6] vs 78·9% [75·2–82·1]; HR 0·66 [95% CI 0·50–0·88]; p=0·0035). 5-year progression-free survival for PET-2-positive patients was 60·6% (95% CI 45·0–73·1) with A+AVD versus 45·9% (32·7–58·2) with ABVD (HR 0·70 [95% CI 0·39–1·26]; p=0·23). Peripheral neuropathy continued to improve or resolve over time with both A+AVD (375 [85%] of 443 patients) and ABVD (245 [86%] of 286 patients); more patients had ongoing peripheral neuropathy in the A+AVD group (127 [19%] of 662) than in the ABVD group (59 [9%] of 659). Fewer secondary malignancies were reported with A+AVD (19 [3%] of 662) than with ABVD (29 [4%] of 659). More livebirths were reported in the A+AVD group (n=75) than in the ABVD group (n=50). Interpretation With 5 years of follow-up, A+AVD showed robust and durable improvement in progression-free survival versus ABVD, regardless of PET-2 status, and a consistent safety profile. On the basis of these findings, A+AVD should be preferred over ABVD for patients with previously untreated stage III or IV classical Hodgkin lymphoma. Funding Millennium Pharmaceuticals (a wholly owned subsidiary of Takeda Pharmaceutical Company), and Seagen.

Approximately one‐third of patients diagnosed with Hodgkin lymphoma presenting with Stage IV disease do not survive past 5 years. We present updated efficacy and safety analyses in high‐risk patient subgroups, defined by Stage IV disease or International Prognostic Score (IPS) of 4–7, enrolled in the ECHELON‐1 study that compared brentuximab vedotin plus doxorubicin, vinblastine, and dacarbazine (A + AVD) versus doxorubicin, bleomycin, vinblastine, and dacarbazine (ABVD) as first‐line therapy after a median follow‐up of 37.1 months. Among patients treated with A + AVD (n = 664) or ABVD (n = 670), 64% had Stage IV disease and 26% had an IPS of 4–7. Patients with Stage IV disease treated with A + AVD showed consistent improvements in PFS at 3 years as assessed by investigator (hazard ratio [HR], 0.723; 95% confidence interval [CI], 0.537–0.973; p = 0.032). Similar improvements were seen in the subgroup of patients with IPS of 4–7 (HR, 0.588; 95% CI, 0.386–0.894; p = 0.012). The most common adverse events (AEs) in A + AVD‐treated versus ABVD‐treated patients with Stage IV disease were peripheral neuropathy (67% vs. 40%) and neutropenia (71% vs. 55%); in patients with IPS of 4–7, the most common AEs were peripheral neuropathy (69% vs. 45%), neutropenia (66% vs. 55%), and febrile neutropenia (23% vs. 9%), respectively. Patients in high‐risk subgroups did not experience greater AE incidence or severity than patients in the total population. This updated analysis of ECHELON‐1 shows a favorable benefit‐risk balance in high‐risk patients.

An effective antitumor immune response in patients with lymphoma would eradicate the malignant B cells and cure the patient of the disease. This, however, does not occur, and a suboptimal antitumor response results in persistence and subsequent progression of the patient’s disease. The goals of immunotherapy are therefore to restore an effective antitumor immune response by promoting immune recognition, optimizing immune activation, and supporting persistence of the immune response resulting in subsequent immunological memory. Multiple mechanisms, however, are present within the tumor microenvironment that account for an inadequate immune response. These include loss of major histocompatibility complex expression on tumor cells and subsequent inadequate antigen presentation, increased expression of immunosuppressive ligands on malignant cells, populations of immune cells with suppressive function present in the tumor, and cytokines secreted by the malignant cell or other cells in the microenvironment that promote immune exhaustion or suppress the immune response. Successful immunotherapeutic strategies are specifically addressing these issues by promoting antigen presentation, improving recognition of the malignant cell, directly activating T cells and natural killer cells, and blocking immune checkpoint signaling that would suppress the immune response. Many of these approaches have proven highly successful in patients with various subtypes of lymphoma and are now being incorporated into standard clinical practice.

Key Points Systemic immune microenvironment signatures in CMML indicate an altered T- and natural killer cell balance. CMML bone marrow dendritic cell aggregates associate with disease progression and systemic regulatory T-cell phenotypic switch.

Background Experience with sequential hematopoietic stem cell transplant (HSCT) and kidney transplant (KT) is limited. Methods We conducted a retrospective observational study of adult patients who underwent both HSCT and KT at our center, with a median follow-up of 11 years. Results In our 54 patients cohort (94% autologous HSCT), 36 (67%) patients received HSCT first followed by KT, while 18 (33%) received KT prior to HSCT. In both groups, AL amyloidosis represented 50% of hematologic diagnosis. Only 4 patients expired due to hematologic disease relapse (2 patients in each group) and only 3 allografts were lost due to hematologic disease recurrence (HSCT first n=1 and KT first n=2). Overall 1-year, 5 years and 10 years death-censored graft survival rates were 94%, 94%, and 94%, respectively for HSCT first group and 89%, 89%, and 75%, respectively for KT first group. Overall 1-year, 5 years and 10 years patients survival rates were 100%, 97% and 90%, respectively for HSCT first group and 100%, 76% and 63%, respectively for KT first group. Conclusions Our study supports safety of sequential KT and HSCT, with improved overall patient survival compared to recipients of HSCT remaining on dialysis and good long-term kidney allograft outcome.

Immune checkpoint inhibitors (ICIs) have revolutionized the therapeutic landscape of cancer over the past decade with significant improvement in survival for patients with metastatic melanoma, lung...

This phase 1-2 study evaluated brentuximab vedotin (BV) combined with nivolumab (Nivo) as first salvage therapy in patients with relapsed/refractory (r/r) classical Hodgkin lymphoma (cHL). In parts 1 and 2, patients received staggered dosing of BV and Nivo in cycle 1, followed by same-day dosing in cycles 2 to 4. In part 3, both study drugs were dosed, same day, for all 4 cycles. At end of study treatment, patients could undergo autologous stem cell transplantation (ASCT) per investigator discretion. The objective response rate (ORR; N = 91) was 85%, with 67% achieving a complete response (CR). At a median follow-up of 34.3 months, the estimated progression-free survival (PFS) rate at 3 years was 77% (95% confidence interval [CI], 65% to 86%) and 91% (95% CI, 79% to 96%) for patients undergoing ASCT directly after study treatment. Overall survival at 3 years was 93% (95% CI, 85% to 97%). The most common adverse events (AEs) prior to ASCT were nausea (52%) and infusion-related reactions (43%), all grade 1 or 2. A total of 16 patients (18%) had immune-related AEs that required systemic corticosteroid treatment. Peripheral blood immune signatures were consistent with an activated T-cell response. Median gene expression of CD30 in tumors was higher in patients who responded compared with those who did not. Longer-term follow-up of BV and Nivo as a first salvage regimen shows durable efficacy and impressive PFS, especially in patients who proceeded directly to transplant, without additional toxicity concerns. This trial was registered at www.clinicaltrials.gov as #NCT02572167.

Purpose: TTI-621 (SIRPα-IgG1 Fc) is a novel checkpoint inhibitor that activates antitumor activity by blocking the CD47 “don't eat me” signal. This first-in-human phase I study (NCT02663518) evaluated the safety and activity of TTI-621 in relapsed/refractory (R/R) hematologic malignancies. Patients and Methods: Patients with R/R lymphoma received escalating weekly intravenous TTI-621 to determine the maximum tolerated dose (MTD). During expansion, patients with various malignancies received weekly single-agent TTI-621 at the MTD; TTI-621 was combined with rituximab in patients with B-cell non-Hodgkin lymphoma (B-NHL) or with nivolumab in patients with Hodgkin lymphoma. The primary endpoint was the incidence/severity of adverse events (AEs). Secondary endpoint included overall response rate (ORR). Results: Overall, 164 patients received TTI-621: 18 in escalation and 146 in expansion (rituximab combination, n = 35 and nivolumab combination, n = 4). On the basis of transient grade 4 thrombocytopenia, the MTD was determined as 0.2 mg/kg; 0.1 mg/kg was evaluated in combination cohorts. AEs included infusion-related reactions, thrombocytopenia, chills, and fatigue. Thrombocytopenia (20%, grade ≥3) was reversible between doses and not associated with bleeding. Transient thrombocytopenia that determined the initial MTD may not have been dose limiting. The ORR for all patients was 13%. The ORR was 29% (2/7) for diffuse large B-cell lymphoma (DLBCL) and 25% (8/32) for T-cell NHL (T-NHL) with TTI-621 monotherapy and was 21% (5/24) for DLBCL with TTI-621 plus rituximab. Further dose optimization is ongoing. Conclusions: TTI-621 was well-tolerated and demonstrated activity as monotherapy in patients with R/R B-NHL and T-NHL and combined with rituximab in patients with R/R B-NHL.

Non-Hodgkin lymphomas comprise a heterogenous group of disorders which differ in biology. Although response rates are high in some groups, relapsed disease can be difficult to treat, and newer approaches are needed for this patient population. It is increasingly apparent that the immune system plays a significant role in the propagation and survival of malignant cells. Immune checkpoint blocking agents augment cytotoxic activity of the adaptive and innate immune systems and enhance tumor cell killing. Anti-PD-1 and anti-CTLA-4 antibodies have been tested as both single agents and combination therapy. Although success rates with anti-PD-1 antibodies are high in patients with Hodgkin lymphoma, the results are yet to be replicated in those with non-Hodgkin lymphomas. Some lymphoma histologies, such as primary mediastinal B cell lymphoma (PMBL), central nervous system, and testicular lymphomas and gray zone lymphoma, respond favorably to PD-1 blockade, but the response rates in most lymphoma subtypes are low. Other agents including those targeting the adaptive immune system such as TIM-3, TIGIT, and BTLA and innate immune system such as CD47 and KIR are therefore in trials to test alternative ways to activate the immune system. Patient selection based on tumor biology is likely to be a determining factor in treatment response in patients, and further research exploring optimal patient populations, newer targets, and combination therapy as well as identifying biomarkers is needed.

Summary Background Recognising that the immune suppressive microenvironment promotes tumour growth in Hodgkin lymphoma, we hypothesised that activating immunity might augment the activity of targeted chemotherapy. We evaluated the safety and activity of combinations of brentuximab vedotin with nivolumab or ipilimumab, or both in patients with relapsed or refractory Hodgkin lymphoma. Methods In this multicentre, open-label, phase 1/2 trial, patients with relapsed or refractory Hodgkin lymphoma aged 18 years or older who had relapsed after at least one line of therapy, with an Eastern Cooperative Oncology Group performance status of 2 or lower, and adequate organ and marrow function, with no pulmonary dysfunction were eligible for inclusion. Phase 1 primary objectives were to determine the maximum tolerated dose and dose limiting toxicities of brentuximab vedotin combined with ipilimumab (ipilimumab group), nivolumab (nivolumab group), or both (triplet therapy group) using a 3 + 3 dose escalation design with expansion cohorts. During the dose escalation phase, patients were enrolled sequentially into one of six cohorts: in the ipilimumab group fixed brentuximab vedotin 1·8 mg/kg with ipilimumab 1 mg/kg (cohort A) or 3 mg/kg (cohort B); in the nivolumab group fixed nivolumab 3 mg/kg with brentuximab vedotin 1·2 mg/kg (cohort D) or 1·8 mg/kg (cohort E); and in the triplet therapy group fixed nivolumab 3 mg/kg and ipilimumab 1 mg/kg with brentuximab vedotin 1·2 mg/kg (cohort G) or 1·8 mg/kg (cohort H). Additional patients were enrolled in the expansion phase at the same doses of cohorts B, E, and H. All drugs were given intravenously; brentuximab vedotin and nivolumab were given every 3 weeks, ipilimumab was given every 6 weeks in the ipilimumab group and every 12 weeks in the triplet therapy group. All eligible and treated patients were included in the analysis. This phase 1/2 study is registered with ClinicalTrials.gov , NCT01896999 . The phase 2, randomised portion of the trial is still enrolling. Findings Between March 7, 2014, and Dec 28, 2017, 64 patients were enrolled; two patients in the ipilimumab group and one patient in the nivolumab group were excluded due to ineligibility after enrolment and 61 were evaluable. A total of six dose limiting toxicities were reported in four patients, and the doses used in cohorts B, E, and H were established as maximum tolerated doses and patients were subsequently enrolled onto expansion cohorts (C, F, and I) with these schedules. There were ten (43%) grade 3–4 treatment related adverse events in the ipilimumab group, three (16%) in the nivolumab group, and 11 (50%) in the triplet therapy group including: eight (13%) of 64 patients reporting rash, and colitis, gastritis, pancreatitis and arthritis, and diabetic ketoacidosis each occurring in one (2%) patient. There were two (3%) treatment related deaths, one in the nivolumab group and one in the triplet therapy group. The overall response rate was 76% (95% CI 53–92) in the ipilimumab group, 89% (65–99) in the nivolumab group, and 82% (60–95) in the triplet therapy group, and the complete response rate was 57% (95% CI 34–78%) in the ipilimumab group, 61% (36–83%) in the nivolumab group, and 73% (50–89%) in the triplet therapy group. With a median follow-up of 2·6 years (IQR 1·8–2·9) in the ipilimumab group, 2·4 years (2·2–2·6) in the nivolumab group, and 1·7 years (1·6–1·9) in the triplet therapy group, median progression-free survival is 1·2 years (95% CI 1·7–not reached) in the ipilimumab group, but was not reached in the other two treatment groups. Median overall survival has not been reached in any of the groups. Interpretation There are clear differences in activity and toxicity of the three combination regimens. The tolerability and preliminary activity for the two most active regimens, brentuximab vedotin with nivolumab and the triplet therapy, are being compared in a randomised phase 2 trial ( NCT01896999 ). Funding Eastern Cooperative Oncology Group–American College of Radiology Imaging Network and the National Cancer Institute of the National Institutes of Health.

Ibrutinib is associated with durable responses in patients with Waldenstrom macroglobulinaemia (WM). We hypothesized that response depth is predictive of progression-free survival (PFS) in WM patients treated with ibrutinib. Using landmark analyses, we evaluated response depth in two cohorts of WM patients treated with ibrutinib monotherapy. The learning cohort was composed of 93 participants from two clinical trials, and the validation cohort of 190 consecutive patients treated off clinical trial. Rates of partial response (PR) or better at six months in learning and validation cohorts were 64% and 71% respectively (P = 0·29). In the learning cohort, three-year PFS rates for patients who attained PR or better at six months versus not were 81% and 57% respectively (P = 0·009). In the validation cohort, three-year PFS rates for patients who attained PR or better at six months versus not were 83% and 54% respectively (P = 0·008). In multivariate analyses, attaining PR or better at six months was associated with superior PFS in the learning [hazard ratio (HR) 0·38; P = 0·01] and validation cohorts (HR 0·18; P = 0·004). Attaining PR at six months on ibrutinib emerges as an intermediate outcome of interest and should be validated as surrogate for PFS in clinical trials evaluating Bruton tyrosine kinase inhibitors in WM.

Daratumumab was associated with an overall response of 23% and a median PFS of 2 months in previously treated patients with WM. The 2 patients who attained a partial response to daratumumab exhibited higher baseline CD38 median fluorescent intensity in plasma cells.

Waldenstrom Macroglobulinemia (WM) is a rare, indolent B-cell lymphoma characterized by lymphoplasmacytic involvement of the bone marrow and serum IgM monoclonal protein of any size [1]. The clinic...

A paucity of randomized phase III clinical trials in primary central nervous system lymphoma (PCNSL) has resulted in no uniform consensus on the optimal strategy for consolidation and conditioning regimens for autologous stem cell transplant (ASCT). The past 2 decades have witnessed a preference for thiotepa (TT)-based conditioning regimens due to superior central nervous system penetration. We retrospectively evaluated outcomes of patients with PCNSL who underwent ASCT at Mayo Clinic, Rochester over the past 2 decades, and the impact of TT-based conditioning regimens. Fifty-six patients underwent transplant for PCNSL, with 25 and 31 patients receiving BEAM (non-thiotepa) and carmustine (BCNU)/TT-based conditioning, respectively. All patients received high-dose methotrexate-based induction therapy. While the BCNU/TT group had higher risk disease features such as high International Extranodal Lymphoma Study Group prognostic score, elevated cerebrospinal fluid protein, and older patient population, there was no significant difference at 2 years post-transplant in progression-free survival (BEAM 68.0% [46.1% to 82.5%] versus BCNU/TT, 65.5% [45.2% to 79.8%], P = .99) or overall survival (OS) (84.0% [62.8% to 93.7%] in the BEAM group versus 81.6% [61.3% to 91.9%] in the BCNU/TT group, P = .95). Disease response status before transplant significantly affected the outcomes as those in complete remission had an OS at 2 years post-transplant of 94.7% (68.1% to 99.2%) in the BEAM group and 90.5% (67.0% to 97.5%) in the BCNU/TT group compared with those in partial response, 57.1% (17.2% to 83.7%) in BCNU/TT group and 50.0% (11.1% to 80.4%) in the BEAM group, respectively (P.0001). Our retrospective cohort adds to the currently available literature and identifies the disease status before transplant as a significant factor affecting survival.

In relapsed/refractory Hodgkin lymphoma (R/R HL), immunotherapies such as the anti-programmed death-1 inhibitor pembrolizumab have demonstrated efficacy as monotherapy and are playing an increasingly prominent role in treatment. The CD30/CD16A-bispecific antibody AFM13 is an innate immune cell engager, a first-in-class, tetravalent antibody, designed to create a bridge between CD30 on HL cells and the CD16A receptor on natural killer cells and macrophages, to induce tumor cell killing. Early studies of AFM13 have demonstrated signs of efficacy as monotherapy for patients with R/R HL and the combination of AFM13 with pembrolizumab represents a rational new treatment modality. Here, we describe a phase 1b, dose-escalation study to assess the safety and preliminary efficacy of AFM13 in combination with pembrolizumab in patients with R/R HL. The primary objective was estimating the maximum tolerated dose; the secondary objectives were to assess safety, tolerability, antitumor efficacy, pharmacokinetics, and pharmacodynamics. In this heavily pretreated patient population, treatment with the combination of AFM13 and pembrolizumab was generally well tolerated, with similar safety profiles compared to the known profiles of each agent alone. The combination of AFM13 with pembrolizumab demonstrated an objective response rate of 88% at the highest treatment dose, with an 83% overall response rate for the overall population. Pharmacokinetic assessment of AFM13 in the combination setting revealed a half-life of up to 20.6 hours. This proof-of-concept study holds promise as a novel immunotherapy combination worthy of further investigation. This phase 1b study was registered at www.clinicaltrials.gov as NCT02665650.

Summary Background Hodgkin lymphoma is potentially curable. However, 15–35% of older patients (ie, >60 years) have a lower response rate, worse survival outcomes, and greater toxicity than younger patients. Brentuximab vedotin and nivolumab exhibit activity in patients with relapsed or refractory Hodgkin lymphoma. We therefore aimed to evaluate the safety and efficacy of brentuximab vedotin and nivolumab in untreated older patients with Hodgkin lymphoma or in younger patients considered unsuitable for standard ABVD (ie, doxorubicin, bleomycin, vinblastine, and dacarbazine) therapy. Methods We did a multicentre, single-arm, phase 2 trial at eight cancer centres in the USA. Previously untreated patients with classic Hodgkin lymphoma were eligible for study enrolment if they were 60 years or older, or younger than 60 years but considered unsuitable for standard chemotherapy because of a cardiac ejection fraction of less than 50%, pulmonary diffusion capacity of less than 80%, or a creatinine clearance of 30 mL/min or more but less than 60 mL/min, or those who refused chemotherapy. Patients were also required to have an Eastern Cooperative Oncology Group (ECOG) performance status of 0–2. Patients received brentuximab vedotin at 1·8 mg/kg (dose cap at 180 mg) and nivolumab at 3 mg/kg both intravenously every 21 days for 8 cycles. The primary endpoint was the overall response, defined as a partial metabolic response or complete metabolic response at the end of 8 cycles of treatment. A per protocol analysis was done including all patients who received treatment in the activity and safety analyses. This study is registered with ClinicalTrials.gov , number NCT02758717 . Findings Between May 13, 2016, and Jan 30, 2019, the study accrued 46 patients. The median age was 71·5 years (IQR 64–77), with two (4%) of 46 patients younger than 60 years. Median follow-up was 21·2 months (IQR 15·6–29·9), and 35 (76%) of 46 patients completed all 8 cycles of therapy. At the interim analysis on Oct 11, 2019, the first 25 evaluable patients had an overall response rate of 64% ([95% CI 43–82] 16 of 25 patients; 13 [52%] had a complete metabolic response and three [12%] had a partial metabolic response). The trial was closed to accrual on Oct 14, 2019, after the interim analysis failed to meet the predefined criteria. In all 46 evaluable patients, 22 (48%) patients achieved a complete metabolic response and six (13%) achieved a partial metabolic response (overall response rate 61% [95% CI 45–75]). 14 (30%) of 46 patients had 16 dose adjustments, primarily due to neurotoxicity. 22 (48%) of 46 patients had peripheral neuropathy (five [11%] patients had grade 3 peripheral neuropathy). Grade 4 adverse events included increased aminotranferases (one [2%] of 46), increased lipase or amylase (two [4%]), and pancreatitis (one [2%]). One (2%) patient died from cardiac arrest, possibly treatment related. Interpretation Although the trial did not meet the prespecified activity criteria, brentuximab vedotin plus nivolumab is active in older patients with previously untreated Hodgkin lymphoma with comorbidities. The regimen was also well tolerated in the majority of patients in this older population. Future trials should be based on optimising the dose and schedule, perhaps combined with other targeted agents that might permit chemotherapy-free strategies in older patients with Hodgkin lymphoma. Funding Seattle Genetics and Bristol Myers Squibb.

Lymphoma microenvironment is a dynamic and well-orchestrated network of various immune and stromal cells that is indispensable for tumor cell survival, growth, migration, immune escape, and drug resistance. Recent progress has enhanced our knowledge of the pivotal role of microenvironment in lymphomagenesis. Understanding the characteristics, functions, and contributions of various components of the tumor niche, along with its bidirectional interactions with tumor cells, is paramount. It offers the potential to identify new therapeutic targets with the ability to restore antitumor immune surveillance and eliminate the protumoral factors contributed by the tumor niche.

Purpose Treatment options are limited for patients with relapsed/refractory diffuse large B-cell lymphoma (DLBCL). Tumor cells can exploit the programmed death-1 checkpoint pathway to evade immune surveillance. In the current study, we evaluated the efficacy and safety of programmed death-1 blockade by nivolumab in patients with relapsed/refractory DLBCL. Methods In this phase II, open-label study, patients with relapsed/refractory DLBCL who were ineligible for autologous hematopoietic cell transplantation (auto-HCT) or who had experienced failure with auto-HCT received nivolumab 3 mg/kg every 2 weeks. We assessed the efficacy and safety of nivolumab as well as genetic alterations of 9p24.1. Results Among 121 treated patients, patients in the auto-HCT–failed cohort (n = 87) received a median of four nivolumab doses and a median of three doses were administered to those in the auto-HCT–ineligible cohort (n = 34). At a median follow-up of 9 months in the auto-HCT–failed cohort and 6 months in the auto-HCT–ineligible cohort, independently assessed objective response rates were 10% and 3%, and median durations of response were 11 and 8 months, respectively. Median progression-free survival and overall survival were 1.9 and 12.2 months in the auto-HCT–failed cohort and 1.4 and 5.8 months in the auto-HCT–ineligible cohort respectively. All three patients with complete remission—3% of the auto-HCT–failed cohort—had durable response (11 or more, 14 or more, and 17 months). Treatment-related grade 3 and 4 adverse events were reported in 24% of patients. The most common were neutropenia (4%), thrombocytopenia (3%), and increased lipase (3%). Of all evaluable samples for 9p24.1 analysis, 16% exhibited low-level copy gain and 3% had amplification. Conclusion Nivolumab monotherapy is associated with a favorable safety profile but a low overall response rate among patients with DLBCL who are ineligible for auto-HCT or who experienced failure with auto-HCT. Genetic alterations of 9p24.1 are infrequent in DLBCL.

Systemic immune tolerance is not well-characterized in chronic myelomonocytic leukemia (CMML). Due to the presence of clonal plasmacytoid dendritic cells (pDC) in CMML, and the established association of lymph node indoleamine 2,3-dioxygenase-1 (IDO1)-positive (+) DC populations (IDC) with systemic immune tolerance in other malignant contexts, we sought to determine the association of IDO1 expression and bone marrow (BM) DC populations with systemic T-cell compartment changes using primary CMML patient samples (BM, plasma, and peripheral blood mononuclear cells) via immunohistochemistry (IHC), liquid chromatography-mass spectrometry (LC-MS), and time-of-flight mass cytometry (CyTOF). Our results highlight that aggregate BM IDC (CD123 and/or CD11c positive) occur in 33% CMML patients at any disease time-point (IHC), correlate with accentuated tryptophan catabolism (LC-MS, increased kynurenine level, median 4.7 versus 3 microM, P=0.049*), systemic regulatory T-cell expansion (CyTOF, %parent cell type, 14.5 versus 4.9%, P=0.04*) and play a role in disease progression, as evidenced by a higher rate of transformation to acute myeloid leukemia (41 versus 13%, P=0.002**), when compared to CMML patients without BM IDC. Our data also highlight a perturbed immune system in CMML with specific systemic immune signatures, particularly type 1, IL-17 producing helper T, CD4 terminal effector and natural killer cell suppression.Key PointsAggregate IDO1+ dendritic cell populations occur in the CMML bone marrow microenvironment, and their presence correlates with disease progression.Systemic immune microenvironment signatures in CMML indicate an altered T- and natural killer (NK)-cell balance. Specifically, suppression of type 1 helper T (Th1), IL-17 producing helper T (Th17), CD4 terminal effector and NK cells.IDO1+ bone marrow dendritic cell populations in CMML are associated with a T-cell compartment shift towards a regulatory T cell phenotype.

Disease overview Hodgkin lymphoma (HL) is an uncommon B-cell lymphoid malignancy affecting 8480 new patients annually and representing approximately 10% of all lymphomas in the United States. Diagnosis Hodgkin lymphoma is composed of two distinct disease entities: classical HL and nodular lymphocyte predominant HL. Nodular sclerosis, mixed cellularity, lymphocyte depletion, and lymphocyte-rich HL are subgroups of classical HL. Risk stratification An accurate assessment of the stage of disease in patients with HL is critical for the selection of the appropriate therapy. Prognostic models that identify patients at low or high risk for recurrence, as well as the response to therapy as determined by positron emission tomography (PET) scan, are used to optimize therapy. Risk-adapted therapy Initial therapy for HL patients is based on the histology of the disease, the anatomical stage and the presence of poor prognostic features. Patients with early stage disease are typically treated with combined modality strategies utilizing abbreviated courses of combination chemotherapy, followed by involved-field radiation therapy. Patients with advanced stage disease receive a longer course of chemotherapy, often without radiation therapy. However, newer agents including brentuximab vedotin and anti-PD-1 antibodies are now being incorporated into frontline therapy. Management of relapsed/refractory disease High-dose chemotherapy (HDCT) followed by an autologous stem cell transplant (ASCT) is the standard of care for most patients who relapse following initial therapy. For patients who fail HDCT with ASCT, brentuximab vedotin, PD-1 blockade, non-myeloablative allogeneic transplant or participation in a clinical trial should be considered.

Purpose: We sought to improve upon frontline bendamustine/rituximab (BR) induction therapy followed by rituximab maintenance in untreated high-risk follicular lymphoma (FL). Patients and Methods: Patients were randomized to BR induction followed by 2-year rituximab maintenance (BR-R), BR with bortezomib and rituximab maintenance (BVR-R), or BR followed by lenalidomide (1 year) with rituximab maintenance (BR-LR). Dual primary objectives were complete remission (CR) rate and 1-year disease-free survival (DFS); 289 patients enrolled (NCT01216683). Results: For induction, 92%, 87%, and 86% of patients randomized to BR-R, BVR-R, or BR-LR received six cycles, respectively. CR rate with BR versus BVR induction was 62% versus 75%, respectively (P = 0.04). One-year DFS rates with BR-R versus BR-LR were 85% versus 67%, respectively (P = 0.0009). This was due to an imbalance in CR rates post-BR induction and discontinuation due to adverse events (AEs). The most common grade 3–4 AEs for BVR versus BR were neutropenia and sensory neuropathy (12% vs Conclusions: Altogether, neither bortezomib added to BR induction nor lenalidomide added to rituximab maintenance immediately post-BR induction is recommended in untreated FL.

Double/triple hit lymphoma (DH/TH), known as high-grade B-cell lymphoma (HGBL), is an aggressive diffuse large B cell lymphoma (DLBCL), defined as having concurrent MYC, BCL2, and/or BCL6 gene rearrangements. While gene rearrangements represent significant genetic events in cancer, copy number alterations (CNAs) also play an important role, and their contributions to rearrangements have yet to be fully elucidated. Using FISH and high-resolution CNA data, we defined the landscape of concurrent gene rearrangements and copy gains in MYC, BCL2, and BCL6, in a cohort of 479 newly diagnosed DLBCL. We also show that concurrent translocations and copy number alterations, in combinations similar to DH/TH, identify a unique subset of DLBCL, alternative DH/TH, that have survival outcomes similar to DH/TH DLBCL patients.

Lymphomas are highly heterogeneous tumors and different histologies are characterized by significant differences in biology. Despite the structural and molecular differences between lymphoma types, it is well recognized that the tumor microenvironment plays a critical role in the lymphoma survival and growth. Over the past few years, understanding of this notion has brought immunotherapy to the forefront of lymphoma treatment by targeting the tumor microenvironment in order to produce an effective anti-tumor response. Thus, the area of lymphoma therapy has changed dramatically within the past few years with the use of checkpoint inhibitors and more recently CAR T-cells. Remarkable results have been reported in some lymphoma types but responses vary significantly between different histologies. Future approaches will focus on combination strategies that will attack lymphoma cells in addition to activating immune responses. These strategies include combinations of different checkpoint blocking antibodies, combinations of checkpoint blocking antibodies with agonistic antibodies, immunomodulatory agents, small molecule inhibitors or CAR T-cells, and armored CAR T-cells. A number of clinical trials testing such combinations are currently under way. In this review, we discuss strategies to modulate the immune response in lymphoma. We specifically address the obstacles to effective activation of the immune system against malignant B-cells and review the current approaches that try to overcome these barriers.

Infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can result in a cytokine storm that is associated with poor outcomes in patients. The activation of a NOD-like receptor pyrin domain containing 3 (NLRP3) inflammasome following SARS-CoV-2 infection has been shown to play a major role in inflammatory immune responses. In this study, we show that open reading frame 8 (ORF8) protein is abundantly secreted as a glycoprotein in vitro. The glycosylated ORF8 stimulates human CD14+/CD16+ monocytes to cause upregulation of proinflammatory cytokine production and cell surface marker expression within 24 hours. The data suggests that stimulation of human monocytes by ORF8 is not receptor mediated. Rather, ORF8 is likely phagocytosed by human monocytes. ORF8 then stimulates the monocytes by independently binding to the NACHT and LRR domains of the NLRP3 protein. Pharmacologic inhibition of NLRP3 significantly diminished the production of pro-inflammatory cytokines from ORF8-stimulated human monocytes. Finally, this study shows that the ORF8 protein is also secreted in patients with newly diagnosed coronavirus disease 2019 (COVID-19). Levels of ORF8 in the blood of patients diagnosed with COVID-19 correlated with disease mortality and trajectory of disease. ORF8 stimulation of monocytes causes pro-inflammatory cytokine production that leads to the development of severe COVID-19.

Purpose: Waldenström's macroglobulinemia is an incurable lymphoproliferative disorder driven by an L265P mutation in the myeloid differentiation primary response gene 88 (MYD88), which activates downstream NF-κB signaling through the Myddosome. As this pathway depends in part on activity of interleukin-1 receptor-associated kinases (IRAKs)-1 and -4, we sought to evaluate the potential of the IRAK1/4 inhibitor R191 in preclinical models. Experimental Design: Patient-derived cell lines and primary samples were used in both in vitro and in vivo experiments to model Waldenström's macroglobulinemia and its response to IRAK1/4 inhibitors. Results: R191 induced a dose- and time-dependent reduction in viability of BCWM.1 and MWCL-1 Waldenström's cell lines, and suppressed activation of IRAK1/4. This was associated with cell-cycle arrest at G0–G1, reduced levels of cyclin-dependent kinases 4 and 6, and induction of apoptosis in cell lines and primary patient samples. Further downstream, R191 exposure led to reduced activation of NF-κB, and of protein kinase B/Akt/mammalian target of rapamycin signaling, whereas expression of a constitutively active Akt mutant induced R191 resistance. Gene expression profiling and gene set enrichment analysis revealed a signature consistent with inhibition of c-Myc and activation of the endoplasmic reticulum stress response. In both subcutaneous and systemic murine models of Waldenström's, R191 showed antitumor activity. Finally, the activity of R191 was enhanced when it was combined with novel chemotherapeutics such as bortezomib, afuresertib, and ibrutinib. Conclusions: Taken together, these data support the translation of R191 as an approach to target IRAK1/4 to the clinic for patients with Waldenström's macroglobulinemia.

Lenalidomide-RCHOP (R2-CHOP21) has been shown to be safe and effective in patients with untreated diffuse large B-cell lymphoma (DLBCL). The aim of this analysis is to report long-term outcome and toxicities in newly diagnosed DLBCL patients who received R2-CHOP21 in two independent phase 2 trials, conducted by Mayo Clinic (MC) and Fondazione Italiana Linfomi (FIL). All patients received R-CHOP21 plus lenalidomide. Long-term progression-free survival (PFS), time to progression (TTP), overall survival (OS) and late toxicities and second tumors were analyzed. Hundred and twelve patients (63 MC, 49 FIL) were included. Median age was 69 years, 88% were stage III–IV. At a median follow-up of 5.1 years, 5y-PFS was 63.5%, 5y-TTP 70.1% and 5y-OS 75.4%; according to cell of origin (COO): 5y-PFS 52.8% vs 64.5%, 5y-TTP 61.6% vs 69.6% and 5y-OS 68.6% vs 74.1% in germinal center (GCB) vs non-GCB respectively. Four patients experienced grade 4–5 late toxicities. Grade ≤ 3 toxicities were infections (N = 4), thrombosis (N = 1) and neuropathy (N = 3). Seven seconds tumors were observed. Long-term follow-up demonstrates that R2-CHOP21 efficacy was maintained with high rates of PFS, TTP, and OS. Lenalidomide appears to mitigate the negative prognosis of non-GCB phenotype. Incidence of therapy-related secondary malignancies and late toxicities were low.

Symptomatic hyperviscosity is a well-established phenomenon in Waldenstrom macroglobulinemia (WM). Monoclonal IgM can variably impact intrinsic serum viscosity, leading to widely disparate symptomatic thresholds for development of hyperviscosity-related symptoms. Data regarding the predictors of symptomatic hyperviscosity and outcomes related to this complication remain scarce and a recent study proposed that IgM >6000 mg/dL be considered a new criterion for initiating therapy in otherwise asymptomatic (smoldering) WM to pre-empt hyperviscosity-related injury. Herein, we attempt to identify predictors of the development of symptomatic hyperviscosity and its impact in patients with WM. Of 997 WM patients evaluated from January, 1996 through June, 2017, symptomatic hyperviscosity was observed in 130 (13%) patients. Overall survival (OS) of these 130 patients was similar to that of patients without symptomatic hyperviscosity (median: 11.5 vs 11.6 years; P = 0.63). On multivariate-analysis, only viscosity >1.8 cp (risk ratio: 4.0, P = 0.02) assessed at the time of WM diagnosis was an independent predictor for the development of subsequent symptomatic hyperviscosity. Among patients with smoldering WM and IgM >6000 mg/dL at diagnosis (n = 13) who were managed expectantly, the median time-to-initial therapy was 6.9 years and only 15% developed hyperviscosity-related symptoms subsequently. In summary, the occurrence of symptomatic hyperviscosity does not impact OS. Serum viscosity at diagnosis of WM, and not IgM concentration, represents the single most important independent predictor for development of subsequent hyperviscosity-related symptoms. Patients with smoldering WM and high serum IgM can be safely observed in the absence of any indications per the Consensus recommendations to initiate WM-directed therapy.

Classic Hodgkin lymphoma has a unique tumor composition in that there is a paucity of malignant cells present, and most of the tumor consists of normal immune and stromal cells. Despite the presence of an immune infiltrate within the tumor microenvironment, the malignant cells effectively evade the immune system and appear to utilize the presence of immune cells to promote the growth and survival of Hodgkin-Reed-Sternberg cells. Hodgkin-Reed-Sternberg cells evade immune detection because of overexpression of programmed death 1 ligands, PD-L1 and PD-L2, which suppress T-cell activation, and loss of expression of major histocompatibility complex molecules that prevent effective immune recognition. Recognition of these immune defects has led to clinical use of immune checkpoint blockade in classic Hodgkin lymphoma. Clinical trials using antibodies that block programmed death 1/PD-L1 signaling have shown remarkable responses to therapy and have led to the approval of nivolumab and pembrolizumab for use in patients with relapsed and refractory disease. Trials are currently testing immune checkpoint blockade in earlier lines of therapy.

CD38 is expressed on Waldenström macroglobulinaemia (WM) cells, but its role as a therapeutic target remains undefined. With recent approval of the anti-CD38 monoclonal antibody, daratumumab (Dara), we hypothesized that blocking CD38 would be lethal to WM cells. In vitro Dara treatment of WM cells (including ibrutinib-resistant lines) elicited antibody-dependent cellular cytotoxicity (ADCC), complement-dependent cytotoxicity (CDC), antibody-dependent cell phagocytosis (ADCP) and direct apoptosis. In vivo, Dara treatment was well tolerated and delayed tumour growth in RPCI-WM1-xenografted mice. CD38 is reported to augment B-cell receptor (BCR) signalling; we noted that Dara significantly attenuated phosphorylated SYK, LYN, BTK, PLCγ2, ERK1/2, AKT, mTOR, and S6 levels, and this effect was augmented by cotreatment with ibrutinib. Indeed, WM cells, including ibrutinib-resistant WM cell lines treated with the ibrutinib + Dara combination, showed significantly more cell death through ADCC, CDC, ADCP and apoptosis relative to single-agent Dara or ibrutinib. In summary, we are the first to report the in vitro and in vivo anti-WM activity of Dara. Furthermore, we show a close connection between BCR and CD38 signalling, which can be co-targeted with ibrutinib + Dara to induce marked WM cell death, irrespective of acquired resistance to ibrutinib.

Objectives Lymphoplasmacytic lymphoma (LPL) remains a poorly defined entity, even with the discovery of MYD88L265P mutations and association with Waldenstrom macroglobulinemia (WM). Among bone marrow (BM)-based, low-grade B-cell lymphoma with plasmacytic differentiation (LGBLPD) and immunoglobulin M (IgM) paraproteins, we sought to determine whether MYD88L265P defines a distinct entity and can help refine diagnostic criteria for LPL. Methods BMs diagnosed with LGBLPD or LPL and serum IgM paraprotein were studied (2007-2013). Clinicopathologic features were reviewed and specimens were tested for MYD88L265P. Results In total, 138 (87%) of 159 cases had MYD88L265P, and 158 of 159 were clinically considered WM. MYD88L265P cases had higher disease burden than MYD88WT. Features associated with MYD88L265P include increased mast cells and lymphocyte (not plasma cell)-predominant infiltrate. Hemosiderin, Dutcher bodies, and paratrabecular growth were not associated with MYD88L265P. Conclusions Our data support a clinicopathologic approach to LPL diagnosis and recognition that it may manifest with varying morphologies, phenotypes, and molecular features.

Purpose Selection bias in clinical trials has consequences for scientific validity and applicability of study results to the general population. There is concern that patients with clinically aggressive disease may not have enrolled in recent diffuse large B-cell lymphoma (DLBCL) trials due to the consent process and the inability to delay therapy for eligibility evaluation. We have examined the diagnosis-to-treatment interval (DTI) and its association with clinical factors and outcome in a clinic-based observational cohort of patients with DLBCL from the United States. Validation of results was performed in an independent, clinical trial-based cohort from Europe. Patients and Methods Patients were prospectively enrolled in the University of Iowa and Mayo Clinic Specialized Programs of Research Excellence Molecular Epidemiology Resource (MER; N = 986) or the Lymphoma Study Association (LYSA) LNH-2003 clinical trials program (N = 1,444). All patients received anthracycline-based immunochemotherapy at initial diagnosis. Associations of DTI with clinical factors and outcome were examined. Outcome was assessed using event-free survival at 24 months from diagnosis (EFS24). Results Median (range) DTI was 15 days (0 to 155 days in the MER and 23 days (0 to 215 days) in LYSA. Shorter DTI was strongly associated with adverse clinical factors, including elevated lactate dehydrogenase levels, poor performance status, B symptoms, and higher International Prognostic Index in both cohorts (all P < .001). Longer DTI was associated with improved EFS24 in both the MER (per-week odds ratio, 0.80; 95% CI, 0.74 to .0.87) and LYSA (per-week odds ratio, 0.90; 95% CI, 0.86 to 0.94); association with EFS24 remained significant after adjustment for International Prognostic Index. Conclusion DTI is strongly associated with prognostic clinical factors and outcome in newly diagnosed DLBCL. DTI should be reported in all clinical trials of newly diagnosed DLBCL and future trials should take steps to avoid selection bias due to treatment delay.

Background and objectives Kidney involvement in Waldenstrom macroglobulinemia is less well described compared with kidney manifestations in multiple myeloma. Design, setting, participants, & measurements Of the 1363 patients seen with Waldenstrom macroglobulinemia and other IgM-secreting B cell lymphoproliferative disorders seen at the Mayo Clinic between 1996 and 2015, 57 kidney biopsies were retrospectively studied. The biopsy findings were correlated with clinical, kidney, and hematologic characteristics. Criteria for inclusion were evidence of a monoclonal IgM protein and availability of a kidney and a bone marrow biopsy for review. Glomerular and tubulointerstitial pathologies were categorized according to whether they were related to the monoclonal IgM. Results Of the 57 patients identified, monoclonal gammopathy–related kidney lesions were identified in 82% (47 of 57 biopsies), whereas nonmonoclonal gammopathy–related kidney lesions were seen in 18% (ten of 57). Monoclonal gammopathy–related kidney lesions included monoclonal Ig–related amyloidosis ( n =19; 33%), nonamyloid glomerulopathy ( n =20, 35%), and tubulointerstitial nephropathies ( n =8; 14%). The most common monoclonal gammopathy–related kidney lesion was monoclonal Ig–related amyloidosis ( n =19; 33%) followed by cryoglobulinemic GN ( n =13; 28%). Lymphoma infiltration was the most common tubulointerstitial lesion ( n =4; 9%). The hematologic diagnosis was Waldenstrom macroglobulinemia in 74% ( n =42), monoclonal gammopathy of renal significance in 16% ( n =9), and marginal zone lymphoma ( n =2), chronic lymphocytic leukemia ( n =2), and low-grade B cell lymphoma ( n =2) in 4% each. Conclusions Our study confirms a diverse variety of kidney lesions in patients with monoclonal IgM gammopathy.

CD30 and programmed cell death protein 1 (PD-1) are two ideal therapeutic targets in classical Hodgkin lymphoma (cHL). The CD30 antibody-drug conjugate (ADC) brentuximab vedotin and the PD-1 antibodies nivolumab and pembrolizumab are highly efficacious in treating relapsed and/or refractory cHL. Ongoing studies are evaluating their efficacy in earlier lines of therapy and have demonstrated encouraging results. These agents are expected to further change the landscape of cHL management. Increased cure rates and reduced long-term toxicity from traditional chemotherapy and radiotherapy are likely with the emergence of these novel targeted therapies.

Background :COVID-19 adversely affects individuals with cancer. Several studies have found that seroconversion rates among patients with hematologic malignancies are suboptimal when compared to patients without cancer. Among patients with hematologic malignancies, seroconversion rates also appear to be influenced by recent treatment and the type of treatment they have received. Patients with non-Hodgkin lymphoma (NHL) and multiple myeloma (MM) are immunocompromised due to impaired humoral and cellular immunity in addition to prescribed immunosuppressive therapy. Chimeric antigen receptor T-cell (CAR T) therapy is now widely used for NHL and MM, but little is known about seroconversion rates after COVID-19 vaccination among these populations. Current national guidelines recommend COVID-19 vaccination to be offered to CAR T recipients as early as three months thereafter. We retrospectively evaluated SARS-CoV-2 spike-binding IgG antibody levels following COVID-19 vaccination among NHL and MM CAR T therapy recipients. Methods:This retrospective study was conducted at three Mayo Clinic sites on NHL and MM patients that received CAR T infusions from Sept 2016 to June 2021. Baseline characteristics were ascertained from medical records. All NHL and MM patients who had received CAR T at any point and were alive at the time that the COVID-19 vaccine first became available were eligible for inclusion for antibody response evaluation. For antibody response to vaccination, antibody spike values > 0.80 U/mL were considered positive. Results: Out of 104 CAR T infusions, 73 patients are alive at the time of this submission. We have had 7 patients with known COVID-19 pre-CAR T and all 7 are currently alive (5 have antibody titers and 2 have not been tested yet). Nineteen patients developed known COVID infection post-CAR T (13 alive and 6 deceased). The mortality of COVID post-CAR T in our sample was 31.5%. Furthermore, of the 13 patients that survived COVID-19, they received CAR T an average of 416 days prior to COVID-19 infection (median = 337, range = 54 - 1406); the 6 patients who died from COVID-19 had received CAR T an average of 250 days prior to COVID-19 infection (median = 164, range = 7 - 846). All 6 deceased patients did not receive COVID-19 vaccination pre-CAR T. Out of 17 CAR T patients tested for antibody spike titers post COVID-19 vaccination, 76.4% were able to mount an antibody response. More patients with MM had a higher titer response to the vaccine (>250 U/mL) compared to the NHL counterparts (0.80-249 U/mL). All patients that received the vaccine, regardless of antibody response, were alive at the time of this submission. Conclusions:The majority of CAR T recipients with NHL and MM are able to mount an antibody response following COVID-19 vaccination in our relatively small sample. The frequency of seroconversion among CAR T recipients seems to be similar to patients with hematologic malignancy who had received a hematopoietic cell transplant reported elsewhere. These findings are limited by our small sample size and may be influenced by the timing of vaccination relative to CAR T. Furthermore, almost half of our patients received IVIG post CAR T which could potentially cause false positive antibody results as pooled immunoglobulin preparations may contain COVID-19 antibodies from vaccinated healthy donors. To better understand the characteristics of the immunologic response against SARS-CoV-2 in patients post-CAR T, larger multicenter studies exploring both humoral and cellular immunity will be needed. JEWN, MI and JM are co-first authors and PV, HM and AR are co-senior authors. Figure 1 Figure 1. Disclosures Munoz: Physicians' Education Resource: Honoraria; Seattle Genetics: Honoraria; Bayer: Research Funding; Gilead/Kite Pharma: Research Funding; Celgene: Research Funding; Merck: Research Funding; Portola: Research Funding; Incyte: Research Funding; Genentech: Research Funding; Pharmacyclics: Research Funding; Seattle Genetics: Research Funding; Janssen: Research Funding; Millennium: Research Funding; Gilead/Kite Pharma, Kyowa, Bayer, Pharmacyclics/Janssen, Seattle Genetics, Acrotech/Aurobindo, Beigene, Verastem, AstraZeneca, Celgene/BMS, Genentech/Roche.: Speakers Bureau; Pharmacyclics/Abbvie, Bayer, Gilead/Kite Pharma, Pfizer, Janssen, Juno/Celgene, BMS, Kyowa, Alexion, Beigene, Fosunkite, Innovent, Seattle Genetics, Debiopharm, Karyopharm, Genmab, ADC Therapeutics, Epizyme, Beigene, Servier: Consultancy; Targeted Oncology: Honoraria; OncView: Honoraria; Kyowa: Honoraria. Bergsagel: Oncopeptides: Consultancy, Honoraria; Novartis: Consultancy, Honoraria, Patents & Royalties: human CRBN mouse; Pfizer: Consultancy, Honoraria; Celgene: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Genetech: Consultancy, Honoraria; GSK: Consultancy, Honoraria. Wang: Incyte: Membership on an entity's Board of Directors or advisory committees, Research Funding; LOXO Oncology: Membership on an entity's Board of Directors or advisory committees, Research Funding; Genentech: Research Funding; InnoCare: Research Funding; Novartis: Research Funding; MorphoSys: Research Funding; Eli Lilly: Membership on an entity's Board of Directors or advisory committees; TG Therapeutics: Membership on an entity's Board of Directors or advisory committees. Fonseca: Juno: Consultancy; Kite: Consultancy; Aduro: Consultancy; OncoTracker: Consultancy, Membership on an entity's Board of Directors or advisory committees; GSK: Consultancy; AbbVie: Consultancy; Patent: Prognosticaton of myeloma via FISH: Patents & Royalties; Caris Life Sciences: Membership on an entity's Board of Directors or advisory committees; Scientific Advisory Board: Adaptive Biotechnologies: Membership on an entity's Board of Directors or advisory committees; BMS: Consultancy; Amgen: Consultancy; Sanofi: Consultancy; Merck: Consultancy; Mayo Clinic in Arizona: Current Employment; Celgene: Consultancy; Takeda: Consultancy; Bayer: Consultancy; Janssen: Consultancy; Novartis: Consultancy; Pharmacyclics: Consultancy. Palmer: Sierra Oncology: Consultancy, Research Funding; CTI BioPharma: Consultancy, Research Funding; Protagonist: Consultancy, Research Funding; Incyte: Research Funding; PharmaEssentia: Research Funding. Dingli: Novartis: Research Funding; GSK: Consultancy; Apellis: Consultancy; Alexion: Consultancy; Sanofi: Consultancy; Janssen: Consultancy. Kapoor: Sanofi: Research Funding; AbbVie: Research Funding; Takeda: Research Funding; Karyopharm: Consultancy; Cellectar: Consultancy; BeiGene: Consultancy; Pharmacyclics: Consultancy; Sanofi: Consultancy; Amgen: Research Funding; Ichnos Sciences: Research Funding; Regeneron Pharmaceuticals: Research Funding; Glaxo SmithKline: Research Funding; Karyopharm: Research Funding. Kumar: Roche-Genentech: Consultancy, Research Funding; Oncopeptides: Consultancy; Abbvie: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; BMS: Consultancy, Research Funding; Beigene: Consultancy; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Research Funding; Adaptive: Membership on an entity's Board of Directors or advisory committees, Research Funding; Astra-Zeneca: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Tenebio: Research Funding; Merck: Research Funding; Carsgen: Research Funding; KITE: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Amgen: Consultancy, Research Funding; Bluebird Bio: Consultancy; Antengene: Consultancy, Honoraria; Sanofi: Research Funding. Paludo: Karyopharm: Research Funding. Bennani: Kymera: Other: Advisory Board; Vividion: Other: Advisory Board; Kyowa Kirin: Other: Advisory Board; Daichii Sankyo Inc: Other: Advisory Board; Purdue Pharma: Other: Advisory Board; Verastem: Other: Advisory Board. Ansell: Bristol Myers Squibb, ADC Therapeutics, Seattle Genetics, Regeneron, Affimed, AI Therapeutics, Pfizer, Trillium and Takeda: Research Funding. Lin: Kite, a Gilead Company: Consultancy, Research Funding; Merck: Research Funding; Gamida Cell: Consultancy; Takeda: Research Funding; Juno: Consultancy; Bluebird Bio: Consultancy, Research Funding; Celgene: Consultancy, Research Funding; Novartis: Consultancy; Janssen: Consultancy, Research Funding; Sorrento: Consultancy; Legend: Consultancy; Vineti: Consultancy. Murthy: CRISPR Therapeutics: Research Funding.

In this phase 2 trial, we sought to evaluate the efficacy and safety of rituximab, cyclophosphamide, bortezomib, and dexamethasone (R-CyBorD) in patients with low-grade NHL. The regimen included rituximab on day 1 with weekly cyclophosphamide, dexamethasone, and bortezomib 1.3 mg/m

Introduction: Up to 40% of newly diagnosed diffuse large B cell lymphoma (DLBCL) will relapse after frontline rituximab, doxorubicin, cyclophosphamide, vincristine, and prednisone (RCHOP), with subsequent poor prognosis. Identification of patients (pts) at high risk of relapse early in the treatment can allow for development of risk adapted therapies to improve outcomes. Positron Emission Tomography scan after 2 cycles of therapy (PET2) has been evaluated as a predictor of relapse but study treatments were heterogenous and results were conflicting. A substudy of CALGB 50303 trial did not find association of PET2 response by Deauville Score (DS) with survival in RCHOP and DA-EPOCH-R treated pts. In the UK National Cancer Research Institute Prospective Study, DS of 5 on PET2 predicted worse progression free survival but not overall survival (OS) in RCHOP-21 and RCHOP-14 treated pts. Here we report impact of PET2 response on outcomes in two large independent, prospective cohorts of newly diagnosed DLBCL treated homogenously with two RCHOP-based regimens of similar efficacy. Methods: Discovery was done in adult pts with DLBCL enrolled into a single arm phase 2 trial of lenalidomide plus standard RCHOP (R2CHOP) (MC078E, NCT00670358). The validation cohort comprised of adult pts with newly diagnosed DLBCL treated with standard RCHOP prospectively enrolled into the Mayo component of the University of Iowa/Mayo Clinic Molecular Epidemiology Resource (MER). Both MC078E and MER cohorts included patients who received at least 3-6 cycles of therapy and had a PET2. Pts who progressed on PET2 were excluded. End of treatment (EOT) PET was done 3-12 weeks after last cycle of therapy. The revised response criteria for malignant lymphoma (Cheson, et al 2007) was used to assess PET in MC078E. In MER, revised response criteria for malignant lymphoma (Cheson et al 2007) or Lugano classification was used, depending on era of diagnosis. Positive PET was defined as FDG uptake above background (Cheson 2007) or DS 4 or 5 (Lugano 2014). Study endpoints were event-free survival (EFS) and OS by PET2 status. Results: Out of 118 pts treated on MC078E, 102 had PET2 (MC078E). The median age at diagnosis was 64 years (range 19-87), 61 (60%) were male, 89 (87%) had advanced stage disease, 46 (45%) had international prognostic index (IPI) of 3-5. 58 (57%) were PET2 Negative (PET2-ve) and 44 (43%) were PET2 Positive (PET2+ve). At EOT PET, 83 (81%) had -ve PET and 15 (15%) had +ve PET. Out of 44 PET2+ve pts, 15 remained +ve at EOT PET. Out of 58 PET2-ve pts, 56 had EOT PET available and all were -ve. Out of 866 DLBCL pts enrolled into MER between August 2005 and June 2015, 621 were treated with RCHOP for 3-6 cycles and 272 had available PET2 (MER). The median age was 65 years (range 55-73), 152 (56%) were male, 174 (64%) had advanced stage, 103 (38%) had IPI 3-5. 186 (68%) were PET2-ve and 86 (32%) were PET2+ve. Out of 235 with EOT PET available, 182 (77%) had -ve EOT PET and 25 (11%) had +ve EOT PET. PET2+ve pts had higher odds of +ve EOT PET (OR: 17.4 (CI 95 8.3-40.0), p In MC078E, 2-year EFS and OS were 69.5% (CI 95 61.1-79.1) and 88.1% (CI 95 82-94.7). In MER, 2-year EFS and OS were 71.6% (CI 95 67.7-76.8) and 82.3% (CI 95 79.3-85.3). Compared to PET2-ve, PET2+ve pts had significantly inferior EFS in both MC078E (HR 4.0, CI 95 2.1-7.88, p Conclusions: Positive PET2 was associated with increased risk of disease progression and death in newly diagnosed DLBCL. Results of our study provide robust evidence of importance of PET2 as an early predictor DLBCL pts at high risk of progression in two independent prospective cohorts. PET2-guided risk-adapted strategies using chimeric antigen receptor T-cell therapy and bispecific antibodies may potentially improve outcomes, should be explored in clinical trials and results of our study serve as a benchmark for such studies. Figure 1 Figure 1. Disclosures Maurer: Kite Pharma: Membership on an entity's Board of Directors or advisory committees; Genentech: Research Funding; Morphosys: Membership on an entity's Board of Directors or advisory committees, Research Funding; Nanostring: Research Funding; Celgene: Research Funding; Pfizer: Consultancy, Membership on an entity's Board of Directors or advisory committees. Wang: Genentech: Research Funding; Eli Lilly: Membership on an entity's Board of Directors or advisory committees; Novartis: Research Funding; MorphoSys: Research Funding; InnoCare: Research Funding; Incyte: Membership on an entity's Board of Directors or advisory committees, Research Funding; LOXO Oncology: Membership on an entity's Board of Directors or advisory committees, Research Funding; TG Therapeutics: Membership on an entity's Board of Directors or advisory committees. Cerhan: Celgene/BMS: Other: Connect Lymphoma Scientific Steering Committee, Research Funding; Regeneron Genetics Center: Other: Research Collaboration; NanoString: Research Funding; Genentech: Research Funding. Ansell: Bristol Myers Squibb, ADC Therapeutics, Seattle Genetics, Regeneron, Affimed, AI Therapeutics, Pfizer, Trillium and Takeda: Research Funding. Habermann: Seagen: Other: Data Monitoring Committee; Incyte: Other: Scientific Advisory Board; Tess Therapeutics: Other: Data Monitoring Committee; Morphosys: Other: Scientific Advisory Board; Loxo Oncology: Other: Scientific Advisory Board; Eli Lilly & Co.,: Other: Scientific Advisor. Witzig: Celgene/BMS, Acerta Pharma, Kura Oncology, Acrotech Biopharma, Karyopharm Therapeutics: Research Funding; Karyopharm Therapeutics, Celgene/BMS, Incyte, Epizyme: Consultancy, Membership on an entity's Board of Directors or advisory committees. Nowakowski: Celgene, NanoString Technologies, MorphoSys: Research Funding; Celgene, MorphoSys, Genentech, Selvita, Debiopharm Group, Kite/Gilead: Consultancy, Membership on an entity's Board of Directors or advisory committees.

Background: Polatuzumab vedotin (Pola), an antibody drug conjugate targeting CD79b received FDA approval in combination with bendamustine and rituximab (Pola-BR) in June 2019. With CAR-T as destination therapy, the option of Pola-BR appears appealing with its superior efficacy and lack of potential interference with CAR-T due to different target antigens. However, clinical concerns remain regarding prolonged lymphopenia associated with benda and CAR-T manufacturing if used before apheresis. We reviewed the single center experience of all patients with exposure to polatuzumab around CAR-T for R/R aggressive NHL treated at Mayo Clinic Rochester. Methods: A review of patients that received at least one dose of Pola with the intent to proceed to CAR-T between July 1, 2019 and March 31st, 2021 at Mayo Clinic, Rochester were included. Response to therapy was based on 2014 Lugano criteria. Overall survival (OS) was defined as the time from CAR-T infusion to death, and event-free survival (EFS) as the time from CAR-T infusion to disease progression, next treatment, or death. Survival curves were calculated using Kaplan-Meier estimates, and were compared between subgroups using the log-rank test. Cox regression was used for multivariate analysis (MVA). Results: A total of 22 patients were identified during the study period. Of these 18 (82%), made it to CAR-T infusion (17 axi-cel, and 1 -tisa cel). 3 patients died due to progressive disease (PD) before CAR-T and one achieved complete remission (CR). In the pre-CAR-T Pola cohort (n = 22), the median age was 65.5 years (39-73), 50% were males, 96% had advanced stage and IPI ≥ 3. Median prior lines of treatment were 4.5 (2-6), 73% had primary refractory disease and 50% had myc rearrangement. 19 (86%) patients received Pola as bridging therapy and 8 were exposed to Pola before T-cell apheresis. Bendamustine was included in the treatment for 79% (15/19) for bridging therapy and 63% (5/8) with exposure pre-apheresis. For those in the bridging group, the overall response rate (ORR) was 26% (5/19), with one patient achieving CR with Pola-BR. Disease control (defined as those in a partial response [PR] or stable disease [SD]) was seen in 47% (9/19) patients. One of the 8 patients with pre-apheresis exposure to Pola, required an additional attempt at CAR-T manufacturing after the initial failure. At a median follow up of 48 weeks, the EFS and OS in 18 patient cohort with pre-CAR-T Pola exposure were 6.7 weeks (95% CI, 4.3-not reached [NR]) and 15 weeks (95% CI, 9.7-NR), respectively. At the data cut off (7/25/2021), 78% patients had died. As traditional chemo for bridging is a particularly poor prognostic group, we compared Pola-BR bridging group (n = 15), to other traditional chemo bridge group (n = 16) in our CAR-T database. Both groups had comparable baseline characteristics as shown in Table 1 except for higher proportion of patients with B-symptoms in the Pola-BR group at time of CAR-T. There was also no difference in the inflammatory markers (CRP and ferritin) at LD or peak level after CAR-T. Table 2 shows outcomes between the 2 groups with comparable any grade CRS, neurotoxicity, pre and post CAR-T infection rates. Best response ORR to CAR-T was higher in the other chemo group vs. Pola BR (81.2% vs. 33%, p = 0.027). There was a significant difference in the 6-month OS rate (other 81.3% [95%CI, 54.5-96] vs. pola 33.3% [95%CI, 11.8- 61.6], p = 0.007) but no significant difference in the 6-month EFS rate (other 37.5% [95%CI, 15.2-64.6%] vs. pola 13.3% [95%CI, 1.7-40.5%] p = 0.12) between the 2 groups (figure 1). On univariate analysis within the chemo type bridging cohort (Pola-BR + other traditional chemo, n = 31), presence of B-symptoms (HR 4.72, p = 0.002), ECOG PS > 2 at CAR-T (HR 6.75, p = 0.0008), and type of bridge therapy (pola HR 6.57, p = 0.009) were associated with worse OS whereas a response to bridge (PR+SD, HR 0.39, 0.031) was favorable. On MVA, association was maintained for bridge type (pola, p Discussion: Pola based bridge was feasible in this US based cohort without significant issues with CAR-T manufacturing or increased infection rates. However, in this retrospective analysis, use of Pola-BR was associated with inferior outcomes compared to other traditional chemotherapy options. Future studies are required to elucidate whether these difference in outcomes stem from a biological basis versus bias in patient selection. Figure 1 Figure 1. Disclosures Wang: TG Therapeutics: Membership on an entity's Board of Directors or advisory committees; MorphoSys: Research Funding; Incyte: Membership on an entity's Board of Directors or advisory committees, Research Funding; Eli Lilly: Membership on an entity's Board of Directors or advisory committees; LOXO Oncology: Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Research Funding; Genentech: Research Funding; InnoCare: Research Funding. Paludo: Karyopharm: Research Funding. Bennani: Kymera: Other: Advisory Board; Vividion: Other: Advisory Board; Kyowa Kirin: Other: Advisory Board; Daichii Sankyo Inc: Other: Advisory Board; Purdue Pharma: Other: Advisory Board; Verastem: Other: Advisory Board. Ansell: Bristol Myers Squibb, ADC Therapeutics, Seattle Genetics, Regeneron, Affimed, AI Therapeutics, Pfizer, Trillium and Takeda: Research Funding. Lin: Bluebird Bio: Consultancy, Research Funding; Celgene: Consultancy, Research Funding; Merck: Research Funding; Kite, a Gilead Company: Consultancy, Research Funding; Novartis: Consultancy; Janssen: Consultancy, Research Funding; Juno: Consultancy; Vineti: Consultancy; Takeda: Research Funding; Gamida Cell: Consultancy; Legend: Consultancy; Sorrento: Consultancy.

Background: While CD19 chimeric antigen receptor T cell therapy (CAR-T) therapy does not use myeloablative chemotherapy, patients with aggressive lymphoma treated with CAR-T are immunosuppressed from lymphodepletion chemotherapy, and prolonged B cell aplasia and hypogammaglobulinemia from CAR-T. The impact of CAR-T on immunologic protection from vaccine-preventable diseases (and thus the need to revaccinate) has not been formally studied. We report the vaccine titers of patients treated with CAR-T at Mayo Clinic, Rochester. Methods: We conducted a retrospective chart review of patients who received CAR-T from 9/2018 to 4/2021 for treatment of aggressive lymphoma at Mayo Clinic, Rochester. Data was collected on anti-viral and anti-bacterial titers prior to CAR-T infusion and at month 3 post CAR-T. Clinical assays for vaccine titers were used for patient assessment and threshold for clinical assays was used to define antibody titer as positive or negative. Results: In our cohort of 87 CAR-T patients, 83 (94%) patients were infused with axicabtagene ciloleucel, 4 (5%) patients received brexucabtagene autoleucel and 1 (1%) received tisagenlecleucel. Prior to CAR-T therapy, positive titer rate was highest for tetanus and lowest for Streptococcus pneumoniae (Strep PNA). Similar trends were seen whether patients had autologous stem cell transplant (ASCT) within 2 years of CAR-T (i.e. within immunization timeframe post ASCT) or not (Table 1). At 3 months post CAR-T, overall seropositivity rates were similar when compared to pre-CAR-T levels for the prior transplant and no prior transplant group. For patients who had received intravenous immunoglobulin (IVIG) supplement prophylactically (for IVIG For patients who did not receive IVIG prophylaxis after CAR-T, seropositivity rate for hepatitis A and B was low. In addition, some of these patients had a loss of seropositivity for Strep PNA (2/5, 40%) and hepatitis A (1/4, 25%). Conclusion: The presence of protective vaccine titers is variable for patients receiving CAR-T therapy, regardless of recent ASCT. The loss of protective titers post CAR-T was low. The need for immunization post CAR-T may remain important regardless of transplant status prior to CAR-T. Prophylactic IVIG does not confer complete immunization protection. Optimal timing for immunization post CAR-T is probably unknown and may need to be considered earlier for patients not on prophylactic IVIG. Further study with longer follow-up is needed to inform the need for immunization and optimal timing post CAR-T. Figure 1 Figure 1. Disclosures Bennani: Kymera: Other: Advisory Board; Vividion: Other: Advisory Board; Kyowa Kirin: Other: Advisory Board; Daichii Sankyo Inc: Other: Advisory Board; Purdue Pharma: Other: Advisory Board; Verastem: Other: Advisory Board. Paludo: Karyopharm: Research Funding. Wang: LOXO Oncology: Membership on an entity's Board of Directors or advisory committees, Research Funding; MorphoSys: Research Funding; Genentech: Research Funding; Novartis: Research Funding; Incyte: Membership on an entity's Board of Directors or advisory committees, Research Funding; TG Therapeutics: Membership on an entity's Board of Directors or advisory committees; Eli Lilly: Membership on an entity's Board of Directors or advisory committees; InnoCare: Research Funding. Ansell: Bristol Myers Squibb, ADC Therapeutics, Seattle Genetics, Regeneron, Affimed, AI Therapeutics, Pfizer, Trillium and Takeda: Research Funding. Lin: Sorrento: Consultancy; Kite, a Gilead Company: Consultancy, Research Funding; Vineti: Consultancy; Juno: Consultancy; Legend: Consultancy; Gamida Cell: Consultancy; Merck: Research Funding; Bluebird Bio: Consultancy, Research Funding; Novartis: Consultancy; Celgene: Consultancy, Research Funding; Janssen: Consultancy, Research Funding; Takeda: Research Funding.

Background: Bridging therapy (BT) was not allowed in the ZUMA-1 pivotal trial for axicabtagene ciloleucel (axi-cel) chimeric antigen receptor T-cell therapy (CAR-T) . Since then, several real-world studies have shown the use of bridging therapy to be associated with worse overall survival, duration of response, and complete remission rates. In addition, patients requiring BT during CAR-T manufacturing have a more aggressive and higher tumor burden of disease, also factors associated with poor outcomes. Therefore, factors that can predict outcomes in this high-risk patient cohort are required. We herein examine the impact of response to BT on CAR-T outcomes in large B-cell lymphoma (LBCL). Methods: A retrospective review of patients who received axi-cel for NHL from June 2016 - July 2020 at Mayo Clinic, Rochester, was performed. BT was defined as any lymphoma-directed therapy given between leukapheresis and CAR-T infusion. Patients received BT if there were concerns for symptomatic progression of disease during CAR-T manufacturing, reducing the likelihood of eligibility to receive CAR-T. The decision and choice of BT were at the discretion of the treating physician. Response to all lymphoma-directed therapy was evaluated using the 2014 Lugano criteria. Response to BT included patients with a partial response (PR) or stable disease (SD) on PET-CT before initiating lymphodepletion chemotherapy. Event-free survival (EFS) was defined as the time from axi-cel infusion to progression, next treatment, or death. Overall survival (OS) was defined as the time from axi-cel infusion to death. Survival curves were calculated using Kaplan-Meier estimates and were compared between subgroups using the log-rank test. Cox regression was used for univariate and multivariate analysis (MVA). Results: A total of 73 patients underwent car T therapy during this period. Of these, 67% (49/73) received BT therapy. Table 1 shows baseline characteristics of the total BT cohort (n = 49). The median age at CAR-T infusion was 59 years (IQR 46-64); 57% were males and comprised of 47% (23/49) DLBCL followed by 31% (15/49) high-grade B-cell lymphoma types. Based on the Lugano criteria on PET-CT, 22/49 (45%) patients responded to BT. The baseline characteristics were comparable between the responders and non-responders to BT except for a higher proportion (73%) of patients receiving systemic chemotherapy as BT in the responders (Table 1). At a median follow-up of 24 months, 75% had either progressed, died, or started the next treatment (event), and 59% (29/49) had died. The median EFS was significantly longer in the responders as compared to the non-responders to BT, figure 1 (13.04 months (95%CI, 3.54-not reached [NR]) vs. 2.56 months (95%CI, 1.18-3.02), p = 0.002). The OS also trended in favor of the responders (median OS 18.4 months (95% CI, 13.44-NR) vs. 11.84 months (95% CI, 5.05-NR), p = 0.092). The responder group also had a higher 6-month CR rate of 50% than 11.1% in the non-responder group (p = 0.004). There were no differences in any grade or grade ≥ 3 cytokine release syndrome and neurotoxicity rates in the two groups. On univariate analysis within the bridging group (n = 49), type of bridge (non-chemo) and response to bridge (PR+SD) were associated with a better EFS. In the MVA, only response to BT maintained significance for EFS (HR 0.34, p = 0.025). Conclusions: Having some control of lymphoma after BT was associated with better EFS and 6-month CR rate. Future studies need to prospectively evaluate the type and response to BT as a prognostic factor for improving outcomes in patients receiving CAR-T. Figure 1 Figure 1. Disclosures Wang: InnoCare: Research Funding; Incyte: Membership on an entity's Board of Directors or advisory committees, Research Funding; LOXO Oncology: Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Research Funding; Genentech: Research Funding; MorphoSys: Research Funding; Eli Lilly: Membership on an entity's Board of Directors or advisory committees; TG Therapeutics: Membership on an entity's Board of Directors or advisory committees. Paludo: Karyopharm: Research Funding. Bennani: Kymera: Other: Advisory Board; Vividion: Other: Advisory Board; Kyowa Kirin: Other: Advisory Board; Daichii Sankyo Inc: Other: Advisory Board; Purdue Pharma: Other: Advisory Board; Verastem: Other: Advisory Board. Ansell: Bristol Myers Squibb, ADC Therapeutics, Seattle Genetics, Regeneron, Affimed, AI Therapeutics, Pfizer, Trillium and Takeda: Research Funding. Lin: Kite, a Gilead Company: Consultancy, Research Funding; Janssen: Consultancy, Research Funding; Novartis: Consultancy; Celgene: Consultancy, Research Funding; Bluebird Bio: Consultancy, Research Funding; Juno: Consultancy; Legend: Consultancy; Sorrento: Consultancy; Gamida Cell: Consultancy; Vineti: Consultancy; Merck: Research Funding; Takeda: Research Funding.

Introduction: Factors contributing to the antitumor activity of systemic oncolytic virotherapy (OV) include (i) generalized innate immune activation due to virus infusion; (ii) direct oncolytic and/or immune-mediated destruction of OV infected tumor cells due to intratumoral spread of the virus infection; (iii) collateral boosting of tumor antigen-specific T cell responses that target uninfected tumor cells. We investigated the relative contributions of these 3 factors T cell lymphoma (TCL) patients (pts) responding to a single intravenous infusion of Voyager-V1, an oncolytic vesicular stomatitis virus (VSV) encoding IFNβ and sodium iodide symporter (NIS) on NCT03017820. Of relevance, the virally encoded IFNβ enhances tumor specificity, boosts proinflammatory activity & serves as a convenient serum biomarker of infection. Methods: In a first in human trial, a single infusion of Voyager-V1 was administered to 15 pts with relapsed refractory hematologic cancers; 4 dose levels (DL) were tested (5x10 9, 1.7x10 10, 5x10 10, 1.7x10 11 TCID50); 7 pts had TCL. Cytokine levels and CRS symptoms were determined as a measure of generalized immune activation; serum IFNβ levels were monitored as a pharmacodynamic biomarker of virus infection; antitumor T cell responses were measured using ELISPOT assays. Results: Of 8 TCL pts, 3 had RECIST responses: PR at DL 2, a CR & PR at DL 4. Most pts experience short lived CRS typically resolving within 24 hours of virus infusion. Serum IFNβ levels increased post-therapy in all pts, typically peaking by 24 hours post virus infusion and returning to baseline by median day 10. T cell responses could not be accurately determined in most cases due to suboptimal T cell viability and/or function after thawing of frozen PBMC. Factors contributing to tumor regression in each of the responding pts appeared to differ significantly, as exemplified by the case reports below. Pt (I) with CTCL experienced grade 1 CRS followed by brisk regression of multiple cutaneous lesions. The PR lasted 3 mo, after relapse of an eye lesion, but responses at other sites deepened after the relapsed lesion was irradiated; pt remained off active therapy for the next 2 yrs. Peak serum IFNβ 4 hours post infusion was only 182 pg/ml suggesting that disease response may have been driven by nonspecific innate immune activation associated with the virus infusion. Pt (IV) (CD30+ PTCL/ cutaneous relapse) had short lived grade 2 CRS, then developed signs of IFNβ toxicity with AST elevation and thrombocytopenia. Oral ruxolitinib was administered for 5 days as IFNβ toxicity mitigation leading to normalization of AST and platelets. All PET-avid tumors regressed completely. This CR continues 16 months post virus infusion. Peak serum IFNβ was 18,213 pg/ml strongly suggesting that response was driven by extensive intratumoral amplification of the virus and oncolytic tumor destruction. Robust CTL responses to tumor neoantigens were detected in this pt at baseline indicating that collateral boosting of tumor-specific T cells may have been responsible for the long term maintenance of this CR Pt (V) (CD30+ PTCL) had short lived grade 2 CRS followed by response at all disease sites (including complete normalization of an enlarged FDG-avid spleen). Her PR ended after 6 months due to relapse in cervical lymph nodes. Peak serum IFNβ level was modest, 600 pg/ml & sustained over 48 hours suggesting slower intratumoral spread of the virus infection. The deepening of the response long after resolution of the oncolytic phase points strongly to a contribution from antitumor CTL but the assay was technically unsatisfactory in this pt. Conclusion: Analysis of the correlative data supports that intravenous Voyager-V1 therapy can recruit diverse antitumor effector mechanisms to impact tumor response in pts with heavily pretreated TCL. Importantly, intratumoral virus amplification, which results in high circulating concentrations of IFNβ, does not necessarily lead to tumor regression perhaps because of defective immune cell recruitment and/or activation in some tumors but not in others. This will be further evaluated in future study participants by performing CTL assays on fresh, rather than frozen PBMC. In conclusion, a single IV infusion of Voyager-V1 shows highly promising activity against treatment refractory TCL and should be further advanced as a new single-shot or combination therapy for this therapeutically challenging indication. Figure 1 Figure 1. Disclosures Witzig: Karyopharm Therapeutics, Celgene/BMS, Incyte, Epizyme: Consultancy, Membership on an entity's Board of Directors or advisory committees; Celgene/BMS, Acerta Pharma, Kura Oncology, Acrotech Biopharma, Karyopharm Therapeutics: Research Funding. Paludo: Karyopharm: Research Funding. Patnaik: StemLine: Research Funding; Kura Oncology: Research Funding. Dispenzieri: Takeda: Research Funding; Alnylam: Research Funding; Pfizer: Research Funding; Oncopeptides: Consultancy; Sorrento Therapeutics: Consultancy; Janssen: Consultancy, Research Funding. Bennani: Kymera: Other: Advisory Board; Vividion: Other: Advisory Board; Kyowa Kirin: Other: Advisory Board; Daichii Sankyo Inc: Other: Advisory Board; Purdue Pharma: Other: Advisory Board; Verastem: Other: Advisory Board. Ansell: Bristol Myers Squibb, ADC Therapeutics, Seattle Genetics, Regeneron, Affimed, AI Therapeutics, Pfizer, Trillium and Takeda: Research Funding. Gertz: Aurora Biopharma: Other: Stock option; Akcea Therapeutics, Ambry Genetics, Amgen Inc, Celgene Corporation, Janssen Biotech Inc, Karyopharm Therapeutics, Pfizer Inc (to Institution), Sanofi Genzyme: Honoraria; Akcea Therapeutics, Alnylam Pharmaceuticals Inc, Prothena: Consultancy; AbbVie Inc, Celgene Corporation: Other: Data Safetly & Monitoring; Ionis Pharmaceuticals: Other: Advisory Board. Dingli: Janssen: Consultancy; Sanofi: Consultancy; GSK: Consultancy; Apellis: Consultancy; Novartis: Research Funding; Alexion: Consultancy. Kumar: Astra-Zeneca: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Beigene: Consultancy; Carsgen: Research Funding; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; BMS: Consultancy, Research Funding; Merck: Research Funding; Oncopeptides: Consultancy; Roche-Genentech: Consultancy, Research Funding; KITE: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Antengene: Consultancy, Honoraria; Tenebio: Research Funding; Novartis: Research Funding; Bluebird Bio: Consultancy; Amgen: Consultancy, Research Funding; Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Abbvie: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Adaptive: Membership on an entity's Board of Directors or advisory committees, Research Funding; Sanofi: Research Funding. Bergsagel: Oncopeptides: Consultancy, Honoraria; Celgene: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria; Genetech: Consultancy, Honoraria; GSK: Consultancy, Honoraria; Novartis: Consultancy, Honoraria, Patents & Royalties: human CRBN mouse; Janssen: Consultancy, Honoraria. Kapoor: Karyopharm: Consultancy; Cellectar: Consultancy; BeiGene: Consultancy; Pharmacyclics: Consultancy; Sanofi: Consultancy; Amgen: Research Funding; Ichnos Sciences: Research Funding; Regeneron Pharmaceuticals: Research Funding; Glaxo SmithKline: Research Funding; Karyopharm: Research Funding; Sanofi: Research Funding; Takeda: Research Funding; AbbVie: Research Funding. Lin: Sorrento: Consultancy; Vineti: Consultancy; Legend: Consultancy; Novartis: Consultancy; Bluebird Bio: Consultancy, Research Funding; Merck: Research Funding; Juno: Consultancy; Celgene: Consultancy, Research Funding; Kite, a Gilead Company: Consultancy, Research Funding; Gamida Cell: Consultancy; Janssen: Consultancy, Research Funding; Takeda: Research Funding. OffLabel Disclosure: VSV-IFNβ-NIS is an oncolytic virus in clinical trial for systemic administration in hematologic malignancies

Backgrounds: Autologous stem cell transplant (ASCT) has been the standard treatment approach for patients with relapsed or high-risk lymphoma for several decades. Despite the improvement in supportive care, age has remained one of the critical factors that determines transplant eligibility and outcomes. Herein, we explored the transplant-related outcomes of patients with lymphoma aged 70 years or older at our institution and compared to those with younger ages. Methods: In this retrospective single center study, we include all patients with diagnosis of lymphoma who underwent ASCT between January 2000 and February 2021 at Mayo Clinic, Rochester, Minnesota. In addition to data obtained from the transplant database, we abstracted data from electronic medical record. We described relevant clinical characteristics and transplant associated outcomes including engraftment, transplant related mortality, relapse incidence, and survival outcomes. We compared the key transplant related outcomes with patients at the younger age group between 65 and 70 years old. Results: A total of 196 patients with lymphoma aged 70 years or older underwent ASCT between January 2000 and February 2021. The median age of patients at the time of ASCT was 72.4 (70.0-78.7) years with 24 patients (12.2%) being older than 75 years old. Of 196 patients, 76 (38.8%) had Charlson comorbidity index of 3 or higher and 10 (5.1%) had performance status of 2 or higher at the time of ASCT. Table 1 summarizes the relevant baseline clinical characteristics of 196 patients in this cohort including the comparison with younger patients (age 65-70 years old, n=296). The most common transplant indication in this cohort was relapsed diffuse large B cell lymphoma. The majority of patients (91.3%) received peripheral blood graft with a median CD34+ cell dose of 5.14x10 6 cells/kg which was significantly lower than younger patients (P=0.01). The rate of neutrophil and platelet engraftment was 99.0% and 98.8% with corresponding median time to engraftment of 13 days for both cell lineages. The 30- and 100-day non-relapse mortality (NRM) of the entire cohort was 1.5% (95%CI 0-3.2%) and 4.6% (95%CI 1.6-7.5%) not statistically different between 70-75 years old and 75 years or older cohorts. With the median follow-up duration of 48 months, the 2-year event free survival (EFS) and overall survival (OS) was 55.9% (95%CI 49.2-63.5%) and 67.4% (95%CI 61.0-74.5%), respectively. Patients from the 70 years old or older cohort had similar EFS but inferior OS compared to the 65-70 years old cohort. However, there was no difference in EFS and OS between 70-75 and >75 years old cohorts. There was overall an improved trend of 30-day NRM, 2-year EFS and 2-year OS over the 3 different transplant periods (Figures). Although not statistically significant, patients who underwent ASCT between 2000 and 2006 had a trend towards higher 30-day NRM compared to patients who were transplanted at later time points (7.3% vs 0%, P=0.06). The major causes of death included progressive lymphoma, infection, and conditioning regimen related organ toxicities. Conclusion: Outcomes of ASCT in older patients with lymphoma have improved over time with an excellent 30-day NRM (0%) in the past recent years. The major cause of treatment failure after ASCT was progressive disease. With appropriate patient selection, ASCT in older patients is feasible and provides acceptable outcomes comparable to the patients from younger age group. Figure 1 Figure 1. Disclosures Paludo: Karyopharm: Research Funding. Ansell: Bristol Myers Squibb, ADC Therapeutics, Seattle Genetics, Regeneron, Affimed, AI Therapeutics, Pfizer, Trillium and Takeda: Research Funding.

Purpose: Axicabtagene ciloleucel (axi-cel) is an anti-CD19 chimeric antigen receptor T-cell (CAR-T) therapy utilized for patients with non-Hodgkin lymphoma (NHL) refractory to at least 2 lines of therapy. F-18 fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) is used to evaluate disease extent prior to CAR-T infusion at two time points: pre-leukapheresis (pre-leuk) approximately 6 weeks prior to CAR-T infusion, and pre-lymphodepletion chemotherapy (pre-LD) approximately 1 week prior to CAR-T infusion. We hypothesized that PET/CT characteristics beyond Lugano criteria, such as metabolic tumor volume (MTV), total lesion glycolysis (TLG), SUV maximum (SUVMax), and changes in these parameters from pre-leuk to pre-LD, may predict for progressive disease (PD), death, and treatment toxicity after CAR-T infusion. Methods: Patients with NHL who received axi-cel on a prospective registry at Mayo Clinic Rochester were included. Lesions on pre-leuk and pre-LD PET/CT scans were segmented with a fixed absolute SUVMax threshold of 2.5 using a semi-automated workflow (LesionID, MIM Software Inc.) with manual modification to exclude physiologic uptake as needed. MTV, TLG, SUVMax, number of lesions, and other lesion characteristics were assessed for each PET/CT, and changes from pre-leuk to pre-LD were calculated. Lesions were categorized as either nodal, spleen, bone, parenchymal (i.e. liver, lung), or soft tissue (i.e. subcutaneous, muscle), and MTV was calculated for each category. Univariate Cox modeling was used to associate relative and directional change in metabolic and volumetric PET/CT characteristics with PD and death, after adjusting for bridging therapy. LASSO method was used for multivariable model selection. Pre-LD PET/CT characteristics were also assessed for association with presence and duration of cytokine release syndrome (CRS), grade 3+ immune effector cell-associated neurotoxicity syndrome (ICANS), tocilizumab (toci) use, and corticosteroid use. Results: From 2018-2020, axi-cel was delivered to 69 patients. Histology included diffuse large B-cell lymphoma (57%), transformed follicular lymphoma (23%), or high-grade lymphoma (19%). Pre-leuk and pre-LD PET/CT scans were performed a median of 46 days and 7 days prior to CAR-T infusion, respectively. Forty patients (58%) received bridging therapy between scans, including 9 (13%) receiving radiotherapy. At a median follow-up of 13 months, 39 (57%) had died and 46 (67%) had PD. Sixty patients (87%) developed CRS following CAR-T infusion for a median duration of 5 days. Presence of pre-LD parenchymal disease was associated with longer duration CRS (p=0.032). Thirty-seven patients (54%) developed ICANS for a median duration of 4.5 days, including 12 (32%) with grade 3+ ICANS. Greater pre-LD total MTV was associated with higher risk of grade 3+ ICANS (p=0.042). Greater pre-LD SUVMax was associated with longer duration ICANS (p=0.032). Nineteen (28%) patients required toci. Greater pre-LD total MTV, SUVMax, TLG, and volume of the largest lesion were associated with increased use of toci (p While no individual pre-leuk or pre-LD PET/CT characteristics were associated with risk of PD or death, increases from pre-leuk to pre-LD in total MTV, total TLG, parenchymal MTV, and nodal MTV were associated with increased risk of PD (Figure 1). Similarly, increases from pre-leuk to pre-LD in parenchymal MTV, nodal MTV, TLG of the largest lesion, and total number of lesions were associated with increased risk of death (p Additional patients and follow-up will be presented. Conclusions: Patients with greater pre-LD MTV had higher risk of grade 3+ ICANS and use of toci or corticosteroids. Increasing metabolic disease burden during CAR-T manufacturing is associated with increased risk of PD and death. A two variable risk score using increasing extranodal disease and increasing TLG of the largest lesion may stratify prognosis prior to CAR-T and inform treatment paradigms. Figure 1 Figure 1. Disclosures Bennani: Verastem: Other: Advisory Board; Purdue Pharma: Other: Advisory Board; Daichii Sankyo Inc: Other: Advisory Board; Kyowa Kirin: Other: Advisory Board; Vividion: Other: Advisory Board; Kymera: Other: Advisory Board. Paludo: Karyopharm: Research Funding. Wang: Genentech: Research Funding; LOXO Oncology: Membership on an entity's Board of Directors or advisory committees, Research Funding; Eli Lilly: Membership on an entity's Board of Directors or advisory committees; Incyte: Membership on an entity's Board of Directors or advisory committees, Research Funding; InnoCare: Research Funding; Novartis: Research Funding; MorphoSys: Research Funding; TG Therapeutics: Membership on an entity's Board of Directors or advisory committees. Ansell: Bristol Myers Squibb, ADC Therapeutics, Seattle Genetics, Regeneron, Affimed, AI Therapeutics, Pfizer, Trillium and Takeda: Research Funding. Lin: Gamida Cell: Consultancy; Janssen: Consultancy, Research Funding; Legend: Consultancy; Novartis: Consultancy; Celgene: Consultancy, Research Funding; Sorrento: Consultancy; Bluebird Bio: Consultancy, Research Funding; Takeda: Research Funding; Kite, a Gilead Company: Consultancy, Research Funding; Merck: Research Funding; Vineti: Consultancy; Juno: Consultancy.

Background CD47 is an innate immune checkpoint that binds signal regulatory protein alpha (SIRPα) and delivers a "don't eat me" signal to suppress macrophage phagocytosis. Overexpression of CD47 can allow tumor cells to escape immune surveillance. TTI-621 (SIRPαFc) is a fusion protein consisting of the CD47 binding domain of human SIRPα linked to the Fc region of human IgG1, designed to enhance phagocytosis and antitumor activity by blocking the CD47-SIRPα interaction between malignant cells and macrophages, and engaging Fcγ receptors. Here we report updates from the dose optimization part of the first-in-human study of TTI-621 (NCT02663518), testing dose levels between 0.5-2.0 mg/kg in patients with cutaneous T-cell lymphoma (CTCL). Methods This study has been conducted in 4 parts. Part 1 tested increasing weekly intravenous doses of TTI-621 based on 3+3 escalation. The maximum tolerated dose was initially determined to be 0.2 mg/kg based on dose limiting toxicity (DLT) of thrombocytopenia [defined as Grade (Gr) 4 of any duration]. Expanded testing followed in patients with hematologic malignancies. In Part 2, most patients received 0.2 mg/kg; however, based on investigator discretion, a subset of patients received escalating doses up to 0.5 mg/kg. In Part 3, patients with T-cell lymphomas received stepwise dose escalations from 0.2 to 0.5 mg/kg over the first 5−8 weeks. Part 4 (dose optimization) of this study, is currently ongoing with weekly TTI-621 treatment escalating in a standard 3+3 manner through 5 planned dose levels including 0.5, 0.7, 1, 1.4, and 2 mg/kg. Dose optimization is being assessed in patients with CTCL. The DLT criteria was modified to require Gr 4 thrombocytopenia lasting >72 hours. Safety monitoring includes weekly clinical laboratories and assessments of adverse events (AEs) per CTCAE v 4.03. Blood samples are obtained for pharmacokinetics and disease assessments are performed per Olsen's criteria. Results In Parts 1−3 (n=214), the most common related AEs were infusion-related reaction (IRR, 43%; 3% Gr ≥3), thrombocytopenia (30%; 22% Gr ≥3), chills (22%; 0% Gr ≥3), and fatigue (16%; 1% Gr ≥3). Objective responses to single agent TTI-621 were achieved in 14/71 (20%) NHL pts including CTCL (n=42, 1 CR, 7 PRs), PTCL (n=22, 2 CRs, 2 PRs) and DLBCL (n=7, 1 CR, 1 PR). In Part 4 as of April 12, 2021, 24 patients (17M/7F, median age 65 years) have enrolled into the 5 dose cohorts including 9 patients in the 2.0 mg/kg dose level. CTCL subtypes enrolled include mycosis fungoides (MF, n=18) and Sézary syndrome (SS, n=6). Disease stage was advanced (≥IIB) in 16 (67%) patients and a median of 3 (range 1−12) prior systemic therapies were received. Related AEs occurred in 19 (79%; 33% Gr ≥3) patients including infusion-related reaction (IRR, 50%; 13% Gr ≥3), thrombocytopenia (33%; 25% Gr ≥3), and neutropenia and headache, (13%, 0% Gr ≥3, each). Thrombocytopenia generally occurred on dosing days, and typically recovered within 2-4 days. A total of 15 IRRs have occurred in 12 (50%) patients at all doses levels. Most IRRs occurred during initial infusions only and typically resolved within the day of occurrence. The occurrence of Gr 3 IRRs prompted the addition of corticosteroids to the pre-medication regimen which largely prevent their occurrence. Aside from IRRs and thrombocytopenia which was manageable, AEs were predominantly Gr ≤2. Pharmacokinetic results reveal continued dose-dependent increases in exposure. Objective responses have been observed in 4 of 20 (20%) evaluable patients to date, including 3 partial responses in 14 patients with MF and 1 complete response in 6 patients with SS. Treatment is ongoing in the patient who achieved CR (10+ months) and in 2 of 3 patients who achieved PR (3 and 4 months). A third patient who achieved PR elected to discontinue study treatment at 5 months to pursue allogeneic stem and progenitor cell transplantation. Conclusions Preliminary results from dose optimization testing indicate that weekly infusions of TTI-621 up to 2 mg/kg are generally well tolerated. In Part 4, an overall response rate of 20% has been observed thus far in patients with CTCL. Testing of TTI-621 in alternative dosing schedules is in progress. With demonstrated good tolerability and robust single agent antitumor activity in heavily pre-treated patients, additional testing of TTI-621 beyond relapsed/refractory lymphoma has started. Disclosures Horwitz: Affimed: Research Funding; ADC Therapeutics, Affimed, Aileron, Celgene, Daiichi Sankyo, Forty Seven, Inc., Kyowa Hakko Kirin, Millennium /Takeda, Seattle Genetics, Trillium Therapeutics, and Verastem/SecuraBio.: Consultancy, Research Funding; Acrotech Biopharma, Affimed, ADC Therapeutics, Astex, Merck, Portola Pharma, C4 Therapeutics, Celgene, Janssen, Kura Oncology, Kyowa Hakko Kirin, Myeloid Therapeutics, ONO Pharmaceuticals, Seattle Genetics, Shoreline Biosciences, Inc, Takeda, Trillium Th: Consultancy; Aileron: Research Funding; Celgene: Research Funding; C4 Therapeutics: Consultancy; Crispr Therapeutics: Research Funding; Daiichi Sankyo: Research Funding; Forty Seven, Inc.: Research Funding; Kura Oncology: Consultancy; Kyowa Hakko Kirin: Consultancy, Research Funding; Millennium/Takeda: Research Funding; Myeloid Therapeutics: Consultancy; ONO Pharmaceuticals: Consultancy; Seattle Genetics: Consultancy, Research Funding; Secura Bio: Consultancy; Shoreline Biosciences, Inc.: Consultancy; Takeda: Consultancy; Trillium Therapeutics: Consultancy, Research Funding; Tubulis: Consultancy; Verastem/Securabio: Research Funding. Foran: pfizer: Honoraria; novartis: Honoraria; servier: Honoraria; bms: Honoraria; revolution medicine: Honoraria; taiho: Honoraria; syros: Honoraria; sanofi aventis: Honoraria; certara: Honoraria; gamida: Honoraria; OncLive: Honoraria; abbvie: Research Funding; boehringer ingelheim: Research Funding; takeda: Research Funding; trillium: Research Funding; aptose: Research Funding; actinium: Research Funding; kura: Research Funding; h3bioscience: Research Funding; aprea: Research Funding; sellas: Research Funding; stemline: Research Funding. Lue: Epizyme: Consultancy; TG Therapeutics: Consultancy; Kymera Therapeutics: Research Funding; AstraZeneca: Speakers Bureau; Kura Oncology: Consultancy. Sawas: Affimed: Research Funding; Roche: Current equity holder in publicly-traded company; Flat Iron Health: Current Employment; Seattle Genetics: Honoraria; Acrotech: Honoraria; Daiichi-Sankyo: Speakers Bureau; Seattle Genetics: Speakers Bureau; Gilead: Speakers Bureau. Feldman: Alexion, AstraZeneca Rare Disease: Honoraria, Other: Study investigator. Sokol: Kyowa-Kirin: Membership on an entity's Board of Directors or advisory committees; Dren Bio: Membership on an entity's Board of Directors or advisory committees. Mei: Janssen: Honoraria; EUSA: Honoraria; TG Therapeutics: Research Funding; Epizyme: Research Funding; BMS: Research Funding; Morphosys: Research Funding; Beigene: Research Funding. Flinn: AbbVie: Consultancy, Other: All Consultancy and Research Funding payments made to Sarah Cannon Research Institute, Research Funding; AstraZeneca: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; BeiGene: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Genentech: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Gilead Sciences: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Great Point Partners: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Iksuda Therapeutics: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Janssen: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Juno Therapeutics: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Kite, a Gilead Company: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; MorphoSys: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Nurix Therapeutics: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Pharmacyclics LLC, an AbbVie Company: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Roche: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Seagen: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Takeda: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; TG Therapeutics: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Unum Therapeutics: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Verastem: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Yingli Pharmaceuticals: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Acerta Pharma: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Agios: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; ArQule: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Calithera Biosciences: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Celgene: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Constellation Pharmaceuticals: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Curis: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Forma Therapeutics: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Forty Seven: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; IGM Biosciences: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Incyte: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Infinity Pharmaceuticals: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Karyopharm Therapeutics: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Loxo: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Merck: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Novartis: Consultancy, Other: All consultancy and research funding payments made to Sarah Cannon Research Institute, Research Funding; Pfizer: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Portola Pharmaceuticals: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Rhizen Pharmaceuticals: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Teva: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Trillium Therapeutics: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Triphase Research & Development Corp.: Other: All research funding payments made to Sarah Cannon Research Institute, Research Funding; Century Therapeutics: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Hutchison MediPharma: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Vincerx Pharma: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Sarah Cannon Research Institute: Current Employment; Servier Pharmaceuticals: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Yingli Pharmaceuticals: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Seagen: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Servier Pharmaceuticals: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute; Unum Therapeutics: Consultancy, Other: All consultancy payments made to Sarah Cannon Research Institute, Research Funding; Johnson & Johnson: Current holder of individual stocks in a privately-held company; Seattle Genetics: Research Funding. Villa: Janssen: Honoraria; Roche: Honoraria; Lundbeck: Honoraria; Celgene: Honoraria; Seattle Genetics: Honoraria; AbbVie: Honoraria; AstraZeneca: Honoraria; Gilead: Honoraria; NanoString Technologies: Honoraria. Percival: Pfizer: Research Funding; Abbvie: Research Funding; Biosight: Research Funding; BMS/Celgene: Research Funding; Cardiff Oncology: Research Funding; Glycomimetics: Research Funding; Nohla Therapeutics: Research Funding; Oscotec: Research Funding; Trillium: Research Funding. Savage: Seattle Genetics: Consultancy, Honoraria; BMS: Consultancy, Honoraria, Other: Institutional clinical trial funding; Merck: Consultancy, Honoraria, Other: Institutional clinical trial funding; AbbVie: Consultancy, Honoraria; Astra-Zeneca: Consultancy, Honoraria; Servier: Consultancy, Honoraria; Roche: Research Funding; Takeda: Other: Institutional clinical trial funding; Beigene: Other: Institutional clinical trial funding; Genentech: Research Funding. Diefenbach: Genentech, Inc./ F. Hoffmann-La Roche Ltd: Consultancy, Honoraria, Research Funding; Seattle Genetics: Consultancy, Honoraria, Research Funding; Bristol-Myers Squibb: Consultancy, Honoraria, Research Funding; Merck Sharp & Dohme: Consultancy, Honoraria, Research Funding; Morphosys: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding; MEI: Consultancy, Research Funding; Gilead: Current equity holder in publicly-traded company; IMab: Research Funding; Celgene: Research Funding; Trillium: Research Funding; Incyte: Research Funding; AbbVie: Research Funding; Perlmutter Cancer Center at NYU Langone Health: Current Employment; IGM Biosciences: Research Funding. Kim: Kyowa Kirin: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Innate: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Corvus: Membership on an entity's Board of Directors or advisory committees, Research Funding; Trillium: Research Funding; Galderma: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Elorac: Research Funding; Portola: Membership on an entity's Board of Directors or advisory committees, Research Funding; Soligenix: Research Funding; Eisai: Research Funding; CRISPR: Research Funding; Regeneron: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Sanofi: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Mundipharma: Honoraria, Membership on an entity's Board of Directors or advisory committees; Secura Bio: Honoraria, Membership on an entity's Board of Directors or advisory committees; Alexion, AstraZeneca Rare Disease: Other: Study investigator; Merck: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees; Seattle Genetics: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Horizon: Research Funding. Lin: Trillium Therapeutics: Current Employment, Current holder of stock options in a privately-held company. Catalano: Trillium Therapeutics: Current Employment, Current holder of stock options in a privately-held company. Petrova: Trillium Therapeutics: Current Employment, Current holder of stock options in a privately-held company. Uger: Trillium Therapeutics: Current Employment, Current holder of stock options in a privately-held company. Molloy: Trillium Therapeutics: Current Employment, Current holder of stock options in a privately-held company. Large: Trillium Therapeutics: Current Employment, Current holder of stock options in a privately-held company. Bruns: Trillium Therapeutics: Current Employment, Current holder of stock options in a privately-held company. Ansell: Bristol Myers Squibb, ADC Therapeutics, Seattle Genetics, Regeneron, Affimed, AI Therapeutics, Pfizer, Trillium and Takeda: Research Funding.

Background: While extranodal involvement by mantle cell lymphoma (MCL) is relatively common, involvement of the central nervous system (CNS) is rare ( Methods: MCL pts with CNS involvement seen at Mayo Clinic between 1/1995-9/2020 were identified using the Mayo Data Explorer tool. CNS involvement was defined by tissue biopsy confirmed CNS MCL, CSF analysis demonstrating lymphoma cells, and/or neuroimaging findings compatible with CNS involvement. A 2:1 control group of MCL pts without CNS involvement, matched by age (+/- 2 years) and year of diagnosis (+/- 1 year), was selected among all MCL cases. Medical records were reviewed for baseline characteristics, treatment modalities, and outcomes. Kaplan-Meier method was used for time to event analysis. Wilcoxon test was used to compare continuous variables and Chi square test was used for categorical variables. Results: Out of 1,753 pts with MCL, 36 (2%) had evidence of CNS involvement, including 4 pts with CNS involvement at initial MCL diagnosis. Baseline characteristics of pts with CNS involvement (CNS MCL group) and those without CNS involvement (control group) are shown in Table 1. At MCL diagnosis, non-CNS extranodal involvement was seen in 30 (83%) pts in the CNS MCL group (24 pts with 1 site and 6 pts with ≥ 2 sites), with bone marrow being the most common extranodal site of involvement (n=24, 67%). For the control group, 54 (75%) pts had extranodal involvement (44 pts with 1 site and 10 pts with ≥ 2 sites), and bone marrow was also the most common extranodal site of involvement (n=50, 69%). Notably, advanced stage disease (stage 3-4) was more commonly seen in the CNS MCL group (n=32, 97%) than in the control group (n=59, 83%) (p=0.04) at MCL diagnosis. Blastoid variant was present in a higher proportion of pts in the CNS MCL group (n=11, 31%) compared to the control group (n=8, 11%) (p=0.02). The CNS MCL group also presented with a higher median serum LDH at diagnosis (239 U/L [range 153-1901] vs. 187 U/L [range 124-588], p=0.02), and higher Ki-67 (40% [range 15-100] vs. 30% [range 10-90], p=0.04) compared to the control group. The most common frontline treatment regimen was anthracycline-based therapies (i.e. R-CHOP, Nordic regimen, R-hyperCVAD) for both groups (58% in CNS MCL group and 56% in control group). 14 (39%) pts in the CNS MCL group underwent autologous stem cell transplant in CR1 vs. 31 pts (43%) in the control group. Similar use of rituximab maintenance was seen in both groups (31% in CNS MCL group and 25% in control group). Median total lines of therapy from initial MCL diagnosis was 3 (range 1-9) in CNS MCL group and 2 (range 1-9) in the control group. The median follow-up from MCL diagnosis was 134 months (95% CI:119-163) for the entire cohort. Median OS from MCL diagnosis was 50.3 months (95% CI: 20.9-71.1) for the CNS MCL group compared to 97.1 months (95% CI: 82.6-192.7; p= Conclusion: In pts with MCL, CNS involvement is associated with worse outcomes as evident by a shorter median OS from initial MCL diagnosis (50 months vs. 97 months). Involvement of the CNS by lymphoma is an important contributor for the shorter OS as suggested by the median OS of only 5 months from CNS involvement. Advanced stage, blastoid variant, elevated LDH, and elevated Ki67 at MCL diagnosis were features more commonly seen in the CNS MCL cohort. Validation of risk factors at initial MCL diagnosis associated with CNS involvement and exploring the role of CNS prophylaxis are important topics for further investigation. Figure 1 Figure 1. Disclosures Paludo: Karyopharm: Research Funding. Wang: Novartis: Research Funding; TG Therapeutics: Membership on an entity's Board of Directors or advisory committees; MorphoSys: Research Funding; InnoCare: Research Funding; Eli Lilly: Membership on an entity's Board of Directors or advisory committees; LOXO Oncology: Membership on an entity's Board of Directors or advisory committees, Research Funding; Incyte: Membership on an entity's Board of Directors or advisory committees, Research Funding; Genentech: Research Funding. Bennani: Purdue Pharma: Other: Advisory Board; Daichii Sankyo Inc: Other: Advisory Board; Kyowa Kirin: Other: Advisory Board; Vividion: Other: Advisory Board; Kymera: Other: Advisory Board; Verastem: Other: Advisory Board. Nowakowski: Celgene, MorphoSys, Genentech, Selvita, Debiopharm Group, Kite/Gilead: Consultancy, Membership on an entity's Board of Directors or advisory committees; Celgene, NanoString Technologies, MorphoSys: Research Funding. Witzig: Karyopharm Therapeutics, Celgene/BMS, Incyte, Epizyme: Consultancy, Membership on an entity's Board of Directors or advisory committees; Celgene/BMS, Acerta Pharma, Kura Oncology, Acrotech Biopharma, Karyopharm Therapeutics: Research Funding. Habermann: Seagen: Other: Data Monitoring Committee; Tess Therapeutics: Other: Data Monitoring Committee; Incyte: Other: Scientific Advisory Board; Morphosys: Other: Scientific Advisory Board; Loxo Oncology: Other: Scientific Advisory Board; Eli Lilly & Co.,: Other: Scientific Advisor. Ansell: Bristol Myers Squibb, ADC Therapeutics, Seattle Genetics, Regeneron, Affimed, AI Therapeutics, Pfizer, Trillium and Takeda: Research Funding.

The tumor microenvironment plays a crucial role in mediating the tumor immune response, thereby affecting patient outcomes in follicular lymphoma (FL). Using CyTOF, we analyzed single cell suspensions created from pre-treatment biopsies in a cohort of 82 FL patients and retrospectively extracted patient clinical parameters. Hierarchical analysis of the tumor microenvironment composition stratified these patients into 4 groups: group 1 represents patients with high percentage of monocyte/macrophages/NK cells; patients from group 2 and 3 are rich of intratumoral T and B cells, respectively. Patients with intermediate number of T and B cells are classed into group 4. Intratumoral T cells from these 4 groups exhibited distinct phenotypical characteristics. Group 1 was enriched with KLRG1 +CD8 + T cells, while group 4 showed increased number of CXCR3 - T EM and CD4 + T N cells. Patients from group 2 and 3 featured with increased number of ICOS + T reg cells and CD57 + T FH cells, respectively. We observed that higher numbers of T cells significantly correlated with early disease stage, lack of B-symptoms, event-free survival at 24 months (EFS24) and a favorable overall and EFS survival in patients with histological grade 1 and 2. However, this association was not seen in patients with histological grade 3a and b, suggesting that T cell-mediated anti-tumor immunity is preserved in low grade patients, but overridden in higher grade patients. CITRUS analysis revealed that a cluster that is CD57 + and PD-1 high was significantly more abundant in patients who had disease progression than patients who had a complete response to therapy, suggesting a role of CD57 + T FH cells in promoting malignant cell growth in FL. Consistent with this finding, we observed that higher number of CD57 + T FH cells correlated with an inferior survival in FL. Using CITE-seq technology, we found that CD57 + T FH cells exhibited a substantially different transcriptome when compared to CD57 - T FH cells. Genes that were differentially upregulated in CD57 + T FH cells when compared to CD57 - T FH cells included genes involved in cell survival, compromised inflammatory response, and metabolism activation including GZMK, CCL4, CST7, DUSP2, LGALS3, CYTOR, CHI3L2, SYNE2, CXCL13, CD27 and FABP5. Taken together, our results indicate different tumor microenvironments among FL patient groups that is associated with variable T-cell phenotype. We found that CD57 + T FH cells play an important role in predicting disease progression and patient prognosis in FL. Figure 1 Figure 1. Disclosures Novak: Celgene/BMS: Research Funding. Ansell: Bristol Myers Squibb, ADC Therapeutics, Seattle Genetics, Regeneron, Affimed, AI Therapeutics, Pfizer, Trillium and Takeda: Research Funding.

Our group published a double blind, randomized phase III study (Porrata et al, BBMT 2016; 22: 1017-1023) showing that the infusion of autograft absolute lymphocyte count (A-ALC) ≥ 0.5 x 10 9 cells/kg is a survival prognostic factor for lymphoma patients undergoing autologous peripheral blood hematopoietic stem cell transplantation (APBHSCT). However, a limitation of the study was the short-term follow-up duration of two years post-APBHSCT. To assess if the A-ALC still provide survival benefit we looked at the 121 lymphoma patients enrolled in the phase III from December 10, 2007 until October 12, 2010 survival outcomes with a longer follow-up duration of up to 13 years post-APBHSCT. Since the accrual for the study, 52 patients had died of recurrence lymphoma, 4 patients of therapy-related acute myelogenous leukemia, 3 patients of unknown causes, 1 patient of acute respiratory distress syndrome, 1 patient of anaplastic astrocytoma, and 1 patient of septic shock. The current median follow-up is 86 months (range: 2.1-158.1 months) for the entire cohort and 127.8 months (range: 5.9-158.1 months) for patients still alive. Patients infused with an A-ALC ≥ 0.5 x 10 9 cells/kg continue to experience superior overall survival (OS) (HR = 0.392, 95%CI 0.224-0.687, P < 0.001) and progression-free survival (PFS) (HR = 0.413, 95%CI 0.253-0.677, P < 0.0004). The 10-year OS rates for the A-ALC ≥ 0.5 x10 9 cells/kg patients was 70% (95% confidence interval [CI], 55%-81%) and for the A-ALC < 0.5 x10 9 cells/kg patients was 36% (95% CI, 25%-49%) (Figure 1A). The 10-year PFS rates for the A-ALC ≥ 0.5 x10 9 cells/kg group was 57% (95% CI, 43%-70%) and for the A-ALC < 0.5 x10 9 cells/kg group was 28% (95% CI, 19%-40%) (Figure 1B). Autograft lymphocyte subset analysis including autograft-CD3 (A-CD3), autograft CD4 (A-CD4), autograft CD8 (A-CD8), and autograft natural killer cells (A-NK), showed that the infusion of A-NK was a predictor for OS (HR = 0.518, 95%CI 0.292-0.919, P < 0.02) and PFS (HR = 0.393, 95%CI 0.230-0.670, P < 0.0006). The 10-year OS rates for the A-NK ≥ 0.09 x10 9 cells/kg patients was 67% (95% confidence interval [CI], 50%-80%) and for the A-NK < 0.09 x10 9 cells/kg patients was 42% (95% CI, 31%-54%) (Figure 1C). The 10-year PFS rates for the A-NK ≥ 0.09 x10 9 cells/kg group was 59% (95% CI, 43%-73%) and for the A-NK < 0.09 x10 9 cells/kg group was 32% (95% CI, 23%-44%) (Figure 1D). Both the A-ALC and A-NK were independent predictor for OS [ A-ALC: HR = 0.367, 95%CI 0.195-0.690, P < 0.001) and A-NK: HR = 0.411, 95%CI 0.275-0.892, P < 0.01] and for PFS [ A-ALC: HR = 0.477, 95%CI 0.271-0.840, P < 0.01) and A-NK: HR = 0.490, 95%CI 0.266-0.903, P < 0.02]. With a longer follow-up of 13 years, this study shows that the infusion of A-ALC continues to provide better clinical outcomes to lymphoma patients undergoing APBHSCT. These study findings support our standard practice changed of not only collecting CD34 stem cell for hematologic engraftment, but also A-ALC for lymphoma patients undergoing APBHSCT to improve clinical outcomes. Further, autograft immune effector studies are warranted such as A-NK to develop a more immunocompetent targeted autologous graft verus tumor effect. Figure 1 Figure 1. Disclosures Ansell: Bristol Myers Squibb, ADC Therapeutics, Seattle Genetics, Regeneron, Affimed, AI Therapeutics, Pfizer, Trillium and Takeda: Research Funding. Paludo: Karyopharm: Research Funding.