Johnston, Patrick B.

Abstract Primary central nervous system lymphoma (PCNSL) is a rare form of non-Hodgkin lymphoma involving the brain, cerebrospinal fluid, or retina/vitreous without systemic involvement. Induction with high-dose methotrexate (HD-MTX) followed by consolidation with autologous stem cell transplant (auto-SCT) has become the standard treatment paradigm for most patients. However, limited data are available regarding the efficacy of a maintenance approach with HD-MTX. Herein, we retrospectively reviewed the characteristics and outcomes of 148 patients diagnosed with PCNSL between October 2010 and June 2022, who underwent HD-MTX–based induction therapy followed by either auto-SCT consolidation (n = 70) or HD-MTX maintenance therapy (n = 37). At a median follow-up time of 4.5 years, the progression-free survival (PFS) was 8.3 years and the overall survival (OS) was not reached. Compared to patients who underwent auto-SCT, patients who received maintenance HD-MTX had a higher median age at diagnosis of 72 vs 62 years and a trend toward higher proportion of patients being Eastern Cooperative Oncology Group 2 or higher (41% vs 29%). At 5-years postinduction treatment initiation, the PFS rates in the auto-SCT cohort and HD-MTX maintenance cohort were 74.6% and 72.6%, respectively, and the OS rates were 76.0% and 82.4%, respectively. Overall, there was no significant difference in PFS or OS based on postinduction management strategy. Our data suggest that maintenance HD-MTX may be a reasonable, time-limited treatment strategy for patients with PCNSL responding to initial induction therapy.

Abstract Background: MCL is a B-cell non-Hodgkin lymphoma for which auto-HCT is often employed in first CR, based on non-randomized phase 2 trials, and a randomized trial (Dreyling et al, Blood 2005) conducted before the advent of more effective induction and maintenance regimens. The TRIANGLE trial (Dreyling et al, Lancet 2024) suggested that auto-HCT may not add benefit to more effective induction and maintenance regimens containing high-dose cytarabine, rituximab and BTK inhibitors. E4151 explored whether auto-HCT benefits pts achieving deep first remission, as measured by a highly sensitive immunoglobulin high throughput sequencing minimal residual disease (MRD) assay. Methods: EA4151 is a four arm trial conducted through the U.S. National Clinical Trials Network (NCTN) and Blood and Marrow Transplant Clinical Trials Network (BMT-CTN). Pts with MCL between the ages of 18 and 70 and in first remission were eligible. After induction, pts underwent PET/CT, bone marrow biopsy, and the clonoSEQ® MRD assay from peripheral blood. Pts in CR with uMRD at 1 in 10-6 sensitivity (uMRD6) were randomized 1:1 to Arm A (auto-HCT + 3 years of maintenance rituximab [MR]) or Arm B (3 years of MR alone), stratified by MIPI-c score and intensive vs non-intensive induction. Pts with either MRD-positive (MRD+) CR or MRD-indeterminate CR (Arm C and Arm D, respsectively) both received auto-HCT + 3 years of MR. Pts who were MRD+ pre-transplant had MRD repeated at day 100. Primary endpoint was to compare overall survival (OS) in Arms A and B, with secondary endpoints including progression-free survival (PFS). Primary analysis population included all randomized pts. As some pts refused their assigned treatment (N=65 [25.3%] for arm A and N=2 [0.8%] for arm B), a “treated as assigned” analysis was also performed. Stratified logrank test was used to compare survival distributions. P-values are two-sided. Results: From Aug 2017 to July 2024, 650 pts were assigned to a treatment arm with 257, 259, 49, and 85 pts enrolled on Arms A, B, C, and D, respectively. Pts were 79% male and 92% white race. Median age was 60 years (range 27-70). MIPI-c was low/low-intermediate (LI) in 63% and high/ high-intermediate (HI) in 37%. Induction was intensive (defined as high-dose cytarabine-containing) in 73% and non-intensive in 27%. A BTK inhibitor was given during induction in 7.2% of pts, and during maintenance in 0.3% of pts. The third pre-planned interim analysis was based on data as of 7/15/24, with median follow up of 2.7 years. The futility boundary was an OS hazard ratio (HR) of 0.984 for Arm A vs B. The estimated OS HR for Arm A vs B in all randomized (n=516) and pts treated as assigned (n=375) were 1.11 (CI 0.71-1.74, p=0.66) and 1.00 (CI 0.58-1.74, p=0.99), respectively and crossed the futility boundary. The 3 year (yr) OS for Arms A and B were 82.1% and 82.7% in all randomized pts, and 86.2% and 84.8% in pts treated as assigned. The estimated PFS HR for Arm A vs B in all randomized and pts treated as assigned were 1.05 (CI 0.71-1.56, p=0.79) and 0.95 (CI 0.59-1.54, p=0.84), respectively. The 3 yr PFS for Arms A and B were 76.6% and 77.4% in all randomized pts, and 81.5% and 80.4% in pts treated as assigned. For Arm C, 3 yr OS and PFS were 81.9% (CI 69.6-96.4%) and 76.9% (CI 64.4-91.7%), respectively. For Arm D, 3 yr OS and PFS were 85.1% (CI 76.0%-95.4%) and 73.4% (62.7-85.9%), respectively. For the MIPI-c low/LI group, 3 yr OS was 84.6% vs 85.7% for Arm A vs B (p=0.96), while in the MIPI-c high/HI group, 3 yr OS was 77.4% vs 77.6% for Arm A vs B (p=0.71). For the intensive induction group, 3 yr OS was 83.0% vs 86.2% for Arm A vs B (p=0.30), while in the non-intensive induction group, 3 yr OS was 79.5% vs 72.8% for Arm A vs B (p=0.48). Exploratory analysis of MRD+ pts (Arm C) showed that pts who converted to uMRD6 post auto-HCT (n=17) had 3 yr OS of 100% and PFS of 100%, whereas those who remained MRD+ (n=13) post auto-HCT had 3 yr OS of 63.6% and PFS of 48.8%. Causes of death (COD) in Arm A were 4.7% lymphoma, 5.1% COVID-19, and 5.0% other/unknown. COD in Arm B were 3.5% lymphoma, 6.6% COVID-19, and 4.6% other/unknown. In Sept 2024, the DSMC recommended termination of accrual and release of trial findings based on these results. Conclusion: In this interim analysis, in the era of highly effective induction and maintenance regimens, MCL pts in first CR with uMRD6 did not benefit from consolidative auto-HCT. Pts who remain MRD+ after induction may benefit from auto-HCT. Longer follow-up will be important to confirm these findings.

Background: Management of cytokine release syndrome (CRS) with chimeric antigen receptor T cell therapy (CAR-T) has evolved in the last decade. First line treatment tocilizumab (toci) was initially given for grade 2 or higher CRS in clinical trials (Toci/CRS≥2). Earlier use of toci in grade 1 CRS was found to be safe without negative impact on clinical response in cohort 4 of ZUMA-1 study for axicabtagene ciloleucel (axi-cel) for B-cell non-Hodgkin lymphoma (NHL; Toci/CRS1). This practice was also adopted for other CAR-T therapies for other disease indications. Subsequently, FDA also updated the package insert for axi-cel in 2021 to include the use of prophylactic dexamethasone (ppx dex) to be given on days 0, 1, 2 of CAR-T infusion based on the results from cohort 6 of ZUMA-1. We examined CRS and ICANS (immune effector cell associated neurologic syndrome) outcome of patients who received FDA approved axi-cel in standard-of-care (SOC) practice with these evolving practices. Of note, adoption of ppx dex has been variable across CAR-T treatment centers in the US (Khurana et al, Blood 2022). At Mayo Clinic Rochester, patients considered high-risk for severe CRS/ICANS (those who received bridging therapy and had LDH above upper limit of normal and/or with secondary CNS involvement or other CNS pathologies) would be considered for ppx dex. Methods: Medical records of patients who received axi-cel in SOC between 2018 and 2023 at Mayo Clinic Rochester were reviewed. ASTCT guideline was used for CRS and ICANS grading. Categorical variables were compared using Chi-squared test and continuous variables were compared using Kruskal-Wallis test. Results: Among 187 pts receiving SOC axi-cel, the median age was 60 years and 121 (65%) were males, 152 (81%) had CRS, of which 73 (39%) were grade ≥2; 97 (52%) had ICANS, of which 65 (35%) were grade ≥2. Of the 152 CRS pts, 54/152 (36%) pts never received toci or ppx/dex. Of the pts who received Toci, 35/152 (23%) received Toci when CRS is at least grade 2 (Toci/CRS≥2), 49/152 (32%) received Toci/CRS1 without ppx dex (Toci/CRS1), and 14 (9%) received ppx dex with Toci given in CRS1 when pts developed CRS (PPX DEX). Baseline demographics were comparable except age (Toci/CRS≥2: 58y; Toci/ CRS1: 63y; ppx dex: 50y; p=0.001) and pre-LD CRP (Toci/CRS≥2: 34mg/L; Toci/ CRS1: 6mg/L; ppx dex: 16mg/L; p=0.002). Pre-LD LDH and ferritin were also comparable. PPX DEX or Toci/CRS1 had significantly lower rate of maximum grade CRS≥2 (PPX DEX: 4 (29%); Toci/ CRS1: 20 (41%); 35 (100%); p<0.001) and duration of CRS (PPX DEX: 2.5d; Toci/ CRS1: 3d; Toci/CRS≥2: 5d; p<0.001). Time to onset of CRS was not statistically different between the 3 groups. Not surprisingly, Toci/CRS1 group had higher overall rate of toci use, compared to . Interestingly, use rate of ≥2 doses of Toci or siltuximab was significantly higher in Toci/CRS1 or PPX DEX (PPX DEX: 8 (57%); Toci/ CRS1: 26 (53%); 9 (26%); p=0.02). Pt who received PPX DEX or Toci/CRS1 had a significantly lower rate of ICANS (PPX DEX: 6 (43%); Toci/ CRS1: 33 (67%); 32 (91%); p=0.001) and rate of max grade ICANS ≥2 (PPX DEX: 3 (21%); Toci/ CRS1: 23 (47%); 27 (77%); p<0.001). The time to onset and duration of ICANS was not different among the 3 groups. Conclusion: Our real-world study shows that earlier use of Toci in grade 1, compared to its first use in grade 2, can result in lower overall incidence of more severe CRS, duration of CRS, incidence of ICANS and more severe ICANS. While we selected patients at higher risk for having more severe CRS in our PPX DEX cohort, experience to date suggests that these patients, compared to toci/CRS>=2 cohort, could also have reduced severity of CRS and ICANS with this updated management.

Background: Chimeric antigen receptor T-cell (CAR-T) therapy has shown substantial promise in treatment of hematological malignancies, including non-Hodgkin Lymphoma (NHL). A subset of patients develop prolonged cytopenia, comprising quality of life, increasing healthcare utilization, and imparting considerable morbidity and mortality. Therapy-related myeloid neoplasms (t-MN), typically seen in patients who receive DNA-damaging agents such as radiotherapy and alkylators, have also been observed in CAR-T recipients. CAR-Hematotox score predicts the development of hematotoxicity in CAR-T recipients using laboratory parameters obtained at lymphodepleting (LD) chemotherapy, a timepoint when the patient has already gone through leukapheresis thus committed to the CAR-T process. Therefore, it is critical to identify patients at the highest risk of prolonged cytopenia and/or t-MN prior to apheresis, making it possible for a better triage of those who will proceed with CAR-T and those who might benefit from other strategies. Methods: A retrospective analysis was conducted in NHL patients who received commercial CAR-T products between January 2018 and March 2024 at Mayo Clinic Rochester, Arizona and Florida. Clinical and laboratory data including age, hemoglobin (Hb), absolute neutrophil count (ANC), platelet (PLT), ferritin, and LDH, obtained at the initial CAR-T evaluation, typically within 1 week of leukapheresis, were used for analysis. Prior lines of therapies including autologous stem cell transplant (ASCT) were collected. Prolonged cytopenias were defined as Hb < 8 g/dL, ANC < 0.5 x 109/L, and/or PLT < 50 x 109/L at 3 months after CAR-T. t-MN was diagnosed per WHO 2016. For prolonged cytopenia, the optimal cutoff points for continuous variables were determined by maximizing the sum of sensitivity and specificity. Logistic regression was then used to determine the factors associated with cytopenia at 3 months post-CAR-T. For t-MN, maximally selected log-rank statistics was used to determine the optimal cutoffs. We used competing risk analysis to determine the factors associated with development of t-MN. Death without t-MN was considered a competing risk. For both analyses, the factors with P < 0.1 in univariate analysis (UVA) were included in multivariate analysis (MVA). Results: Among the 387 NHL patients, with a median follow-up of 11 months (95% CI 8.7 - 12.2 months), 56 (14.4%) developed (41, 10.5% with 1 cytopenia; 14, 3.6% with 2 and 1, 0.2% with cytopenia in all 3 lineages), 20 (5.2%) developed and 315 (81.2%) did not have either. Factors associated with prolonged cytopenia: were age >, PLT ≤ 150, ferritin ≥ 600, and LDH ≥ 250. Univariate analysis identified baseline Hb, ANC, PLT and ferritin to be significantly associated with prolonged cytopenia. MVA identified Hb ≤ 11 (HR = 1.98; 95% CI 1.03-3.85, P = 0.042) and PLT ≤ (HR = 2.56; 95% CI 1.39-4.78; P = 0.003) to be associated with the development of prolonged cytopenia. Factors associated with t-MN:were age > 65 years, Hb ≤ 9 g/dl, ANC < 3.8, PLT ≤ 80, Univariate analysis identified age, Hb, ANC, PLT, ferritin, and ≥ 3 prior lines of treatment to be significantly associated with t-MN. On MVA, age ≥ 65 (HR = 3.91; 95% CI 1.52-10.03; P = 0.004), Hb ≤ 9 (HR = 3.49; 95% CI 1.38-8.85; P = 0.008), ferritin ≥ 300 (HR = 3.06 ; 95% CI 1.08-8.67; P = 0.035) and ≥ 3 prior lines of therapy (HR = 3.25; 95% CI 1.33-7.94 ; P = 0.010) were associated with t-MN development. Association of prolonged cytopenia with t-MN development: Prolonged cytopenia was noted in 45% of patients who developed t-MN and 15% of those who did not (P = 0.002). Cumulative incidence of t-MN at 1 year was 3.3% and the presence of prolonged cytopenia was associated with a higher 1of t-MN (HR 8.93, 95% CI 2.15 - 37.1, P = 0.003). Conclusions: Readily accessible clinical and lab data such as blood count and inflammatory markers at the time of CAR-T evaluation were associated with the development of prolonged cytopenias. Similarly, advanced age, anemia, high ferritin levels and history of ≥3 lines of therapy were associated with the development of t-MN. These findings, when validated in larger dataset, can be used for patient counseling and therapy selection by identifying patients at high-risk of developing hematotoxicity and/or t-MN development.

Background: FL3B is the least common among FL subtypes, accounting for 5-10% of cases. Almost half of FL3B tumors have concurrent diffuse large B cell lymphoma (DLBCL) in the diagnostic tissue biopsy, while FL3B rarely coexists with FL1-2 or FL3A. Several lines of evidence suggest that FL3B displays distinct biological and clinical characteristics resembling aggressive DLBCL rather than the indolent FL1-3A. Accordingly, DLBCL anthracycline-containing regimens, such as R-CHOP, are the mainstay of therapy for FL3B with or without coexisting DLBCL. However, while some studies show that R-CHOP therapy in FL3B was associated with 5-year overall survival (OS) rate of 54%, others report outcomes comparable to FL3A with 79-90% survival. Additional controversy involves the clinical implication of pure FL3B (FL3Bp) vs FL3B with concurrent DLBCL (FL3Bc). Thus, it remains unclear if FL3B clinically resembles DLBCL or lower-grade FL and whether FL3Bp has a different prognosis from FL3Bc. To address these questions, we performed a pooled study of two large prospective multicenter study cohorts to compare the clinical characteristics and outcomes of newly diagnosed FL3B with FL1-2, FL3A and DLBCL patients, all of whom were uniformly treated with frontline R-CHOP. Patients and Methods: Weevaluated 469 newly diagnosed patients with FL1-2 (n=216), FL3A (n=170) and FL3B (n=83) who received R-CHOP within 6 months of diagnosis and 739 de novo DLBCL (GCB n=455 and non-GCB n=284) who were prospectively enrolled into the Molecular Epidemiology Resource (MER) and the Lymphoma Epidemiology of Outcomes (LEO) cohorts between 2002 and 2021. FL3B cases were designated as FL3Bc and FL3Bp based on the presence or absence of coexisting DLBCL, respectively. Histologic diagnosis was determined by an expert pathologist at each participating center and centrally reviewed. Event free survival (EFS) and OS were defined as time from diagnosis to progression, relapse, retreatment or death, and early progression defined as failing to achieve EFS at 24 months (EFS24). Associations between clinical features and EFS or OS were evaluated using Kaplan Meier curves and Cox proportional hazards models unadjusted and adjusted for age and FLIPI (comparisons with FL1-2 and FL3A) or IPI (comparisons with DLBCL). Results: The median age was 61 years (range, 18-94 years). Among FL3B patients, 21 (25%) had FL3Bc and 62 (75%) FL3Bp. Baseline characteristics and outcomes were broadly similar between the two FL3B subtypes. We then compared all FL3B patients to those with lower-grade FL. Patients with FL3B showed similar clinical features to those with FL1-2 and FL3A, with exception for a lower tumor burden. After R-CHOP, FL1-2 patients had an inferior EFS (HR 2.13 95%CI 1.31-3.46) than those with FL3B, whereas there was no difference compared to FL3A. OS was similar across all FL grades. Although FL1-2 patients failed to achieve EFS24 more frequently than FL3B and FL3A (34% vs 18% and 15%, p<0.001), FL3B patients who did fail EFS24 had almost three folds higher risk of subsequent mortality (HR 2.84 95%CI 1.35-6.01) than other FLs. At 5-year follow-up, FL3B patients had twice the risk of relapse with an aggressive subtype (i.e., DLBCL, high-grade B-cell lymphoma) than those with FL1-2 and FL3A, who instead often recurred with indolent disease (i.e., FL1-2, FL3A; p<0.001). We further compared FL3B patients to those with DLBCL classified based on cell-of-origin into GCB and non-GCB subtypes. At diagnosis, patients with FL3B had more favorable clinical features than those with GCB and non-GCB DLBCL. Compared to FL3B, patients with non-GCB DLBCL had an inferior EFS (HR 1.73 95%CI 1.07-2.79) and OS (HR 2.04 95%CI 1.11-3.75), while those with GCB DLBCL did not show a significant difference in EFS (HR 1.41 95%CI 0.88-2.25) or OS (HR 1.69, 95%CI 0.93-3.06) likely due to insufficient statistical power. Patients with FL3B failed EFS24 less frequently than patients with GCB or non-GCB DLBCL (17% vs 25% and 32%; p=0.01). Among patients who failed EFS24, those with FL3B had a similar subsequent OS as both GCB (HR 1.41 95%CI 0.73-2.72) and non-GCB DLBCL (HR 1.27 95%CI 0.65-2.47). Conclusions: We report that FL3Bp and FL3Bc appear clinically similar. While most FL3B patients have a prognosis comparable to FL1-2 and FL3A, 18% exhibit aggressive behavior with poor outcome reminiscent of DLBCL. Future studies with a larger population will be needed to confirm our findings.

Background: Immunochemotherapy is the current standard-of-care frontline therapy for diffuse large B-cell lymphoma (DLBCL). Our group previously reported that addition of the mTOR inhibitor everolimus to R-CHOP resulted in excellent efficacy in the Alliance N1085 trial (Witzig TE et al, Blood Cancer J, 2017, 7(6):e576), with 23 of 24 patients achieving event-free survival at 24 months (EFS24), supporting further investigation of PI3K/mTOR targeting in DLBCL. New insights into molecular classification of DLBCL suggest that multiple genetic subtypes of DLBCL (eg, MCD, BN2, ST2, and EZB per LymphGen classification) may be susceptible to PI3K/mTOR targeting. Therefore, we conducted a phase 1/1b trial to investigate the safety and efficacy of combination therapy with a novel PI3K inhibitor parsaclisib and standard immunochemotherapy. Methods: Adult patients with newly diagnosed DLBCL were eligible if any of the following was present: 1) non-GCB subtype per the Hans algorithm; 2) protein expression of either MYC (≥40%) or BCL2 (≥50%) by immunohistochemistry; or 3) MYC rearrangement by FISH. Patients with high grade B-cell lymphoma with MYC and BCL2 and/or BCL6 rearrangements were also eligible. Phase 1 followed a 3+3 design to determine the maximum tolerated dose (MTD) of parsaclisib (plus R-CHOP) to be used in Phase 1b (dose expansion). The primary efficacy endpoint in phase 1/1b was complete response (CR) rate by PET. A polatuzumab vedotin (Pola) safety lead-in cohort was added later to explore the safety and efficacy of parsaclisib (at MTD) plus Pola-R-CHP. Results: From July 2020 to May 2023, 50 patients were enrolled; 1 patient withdrew consent before study treatment and was excluded from this analysis. Nine patients were treated in Phase 1, 33 in Phase 1b, and 7 in the Pola cohort. The median age at diagnosis was 66 years (range 20-86), and 20 (41%) were female. Two (4%) patients had ECOG PS ≥2, 26 (53%) had elevated LDH, 19 (39%) had >1 extranodal site, 37 (76%) had stage III/IV, and 25 (51%) had high-intermediate or high-risk International Prognostic Index (3-5). 23 (47%) had non-GCB subtype, 23 (46.9%) had MYC or BCL2 single expression, 21 (42.9%) had MYC/BCL2 double expression, and 6 (12%) had MYC rearrangement (2 with BCL2 and/or BCL6 rearrangements). In Phase 1, 3 patients were treated at dose level 1 (parsaclisib 20 mg QD, d1-10) and 6 at dose level 2 (parsaclisib 20 mg QD, d1-14). No dose limiting toxicity was observed. Therefore, dose level 2 for parsaclisib was the MTD and was used in Phase 1b. In the Pola cohort (n=7), only 1 of 6 evaluable patients experienced significant toxicity (grade 3 diarrhea). Among all 49 patients, the most common treatment-related adverse event (TRAE) of any grade included neutropenia (83.7%), thrombocytopenia (79.6%), leukopenia (77.6%), lymphopenia (71.4%), anemia (71.4%), nausea (63.3%), fatigue (40.8%), peripheral sensory neuropathy (36.7%), constipation (24.5%), and diarrhea (22.4%), and the most common grade ≥3 TRAE included neutropenia (71.4%), leukopenia (69.4%), lymphopenia (49.0%), thrombocytopenia (20.4%), anemia (16.3%), febrile neutropenia (6.1%), and diarrhea (6.1%). In Phase 1/1b (n=42), the overall response rate (ORR) to parsaclisib plus R-CHOP was 97.6%, and the CR rate was 90.5%. After a median follow-up of 28.5 months (95% CI 27.7-32.7), the estimated 2-year progression-free survival (PFS) rate was 84.6% (95% CI 73.9-96.8), and the estimated 2-year overall survival (OS) rate was 95.1% (95% CI 88.7-100.0). In the Pola cohort, the ORR to parsaclisib plus Pola-R-CHP was 100% and the CR rate was 100%. After a median follow-up of 15.6 months (95% CI 13.5-NE), 1 patient had disease relapse at 11.95 months, and all patients were alive. Conclusions: Addition of the PI3K inhibitor parsaclisib to R-CHOP or Pola-R-CHP immunochemotherapy is considered safe in patients with newly diagnosed DLBCL. Combination of parsaclisib and standard immunochemotherapy resulted in high ORR and CR rate and encouraging preliminary PFS and OS outcomes patients with high-risk DLBCL. These data support further investigation of PI3K/mTOR targeting in newly diagnosed DLBCL in future trials.

Background: ctDNA clearance after frontline DLBCL tx has shown strong prognostic value for favorable outcomes, with the potential to improve MRD-driven therapeutic strategies and establish MRD as a surrogate endpoint in future studies (Roschewski M, et al. Blood 2022; Goldstein J, et al. Blood 2023). However, further study is needed to evaluate the association of this noninvasive approach with efficacy outcomes after 2L LBCL tx. We previously reported ctDNA analysis after liso-cel infusion in TRANSFORM (NCT03575351; Stepan L, et al. Blood 2023;142[suppl 1]). Here, we describe the predictive value of pre-tx and on-tx ctDNA levels for durable clinical benefit (CR and event-free survival [EFS]) in both liso-cel and SOC arms from TRANSFORM (Kamdar M, et al. J Clin Oncol 2024), evaluating ctDNA as an earlier surrogate for conventional clinical outcomes. Methods: Baseline (prerandomization) and longitudinal ctDNA levels were assessed in randomized pts treated with liso-cel or SOC in TRANSFORM using the phased variant enrichment and detection sequencing assay (PhasED-Seq; Foresight Diagnostics). Phased variants were identified from baseline plasma samples for longitudinal ctDNA monitoring at multiple on-tx time points, as previously described (Stepan L, et al. Blood 2023;142[suppl 1]). Randomization was defined as study Day 1. Association of ctDNA levels with response per independent review committee using Lugano 2014 criteria and EFS was investigated at various predefined time points, including Day 43 (after 2 cycles of salvage immunochemotherapy for SOC; Day 15 after liso-cel infusion), Day 64 (after 3 cycles of salvage immunochemotherapy for SOC; 1 month after liso-cel infusion), and Day 126 (within 2 months after ASCT; 3 months after liso-cel infusion). To assess the surrogacy value of ctDNA, ctDNA-MRD dynamics and ctDNA clearance were investigated within both arms. Results: In pooled analyses combining the liso-cel and SOC arms, higher baseline ctDNA levels (above the median) were associated with shorter EFS (P = 0.05). Pts achieving Day 126 CR had substantial reductions in ctDNA burden vs baseline, while pts with PD or stable disease had persistently high ctDNA levels vs baseline. Achieving undetectable ctDNA at different time points was associated with significantly longer EFS in pooled analyses, observed as early as study visit Day 43, with the strongest association at Day 126. HR (95% CI) for inferior EFS was 3.0 (1.6-5.7) at Day 43, 3.8 (2.1-7.0) at Day 64, and 4.2 (2.3-7.7) at Day 126 in pts with detectable vs undetectable ctDNA. In the analysis by tx arm, consistent with the pooled analyses, ctDNA clearance was associated with EFS benefit at all measured time points with either liso-cel or SOC. Significantly more pts achieved undetectable ctDNA with liso-cel vs SOC during the study (39/63 [62%] vs 25/65 [38%], respectively; P = 0.013), consistent with superior EFS (primary endpoint) with liso-cel in TRANSFORM. All pts in the SOC arm with evaluable ctDNA at Day 126 (n = 28) had received high-dose chemotherapy (HDCT)/ASCT. However, pts with undetectable ctDNA in the liso-cel vs SOC arm had longer EFS at all predefined time points and had statistically longer EFS at Day 126 (SOC vs liso-cel: HR, 3.9 [95% CI, 1.4-10.6]), indicating a deeper and more durable response with liso-cel vs SOC. In pts with CR, ctDNA showed significant predictive value beyond the response assessment at all time points in the liso-cel arm with a HR (95% CI) of 3.8 (1.3-11.0) at Day 64 and 7.0 (2.0-24.3) at Day 126 for EFS in pts with detectable ctDNA vs undetectable ctDNA. Among pts in the SOC arm who experienced subsequent PD despite achieving CR (all received HDCT/ASCT) and undetectable ctDNA at Day 126, serial ctDNA assessment showed consistent reversion to detectable ctDNA at later time points. Conclusions: ctDNA data from TRANSFORM confirm the value of ctDNA as a biomarker for disease burden monitoring and early prediction of durable clinical benefit after 2L LBCL treatment. Furthermore, longitudinal ctDNA molecular response results agree with previously reported clinical efficacy data and confirm the superiority of liso-cel with deeper responses over the historical SOC in 2L LBCL. ctDNA may have a key role as a surrogate endpoint in future LBCL studies, including after CAR T cell therapies.

Background: Zamto-cel is an investigational autologous tandem CD20-CD19-directed non-cryopreserved CAR-T cell product administered as a fresh formulation to patients (pts) with relapsed/refractory Diffuse Large B Cell Lymphoma (r/r DLBCL) in the DALY II USA clinical trial (NCT04792489), a multicenter, open label, single-arm Phase 2 study. Here, we report efficacy and safety outcomes as part of a pre-planned interim analysis of 59 evaluable patients and 69 patients in the safety population. Methods: Eligible adults had r/r DLBCL after at least 2 prior lines of treatment including anti-CD20 monoclonal antibody and anthracycline-containing regimen and measurable disease per Lugano 2014 classification. Zamto-cel was manufactured utilizing CliniMACS Prodigy® (Miltenyi Biotec), a closed, automated system with a 14-day vein-to-vein time and administered as a fresh formulation. Lymphodepletion chemotherapy was initiated during the manufacturing process (either cyclophosphamide/ fludarabine or bendamustine) prior to receiving a single dose of zamto-cel at a dose of 2.5x106 CAR T cells/kg on Day 0. The primary endpoint was overall response rate (ORR) defined as best overall response (BOR) of either complete response (CR) or partial response (PR). Secondary endpoints included complete response rate (CRR), duration of response (DOR), progression-free survival (PFS), overall survival (OS), safety, and CD19 and CD20 antigen expression at relapse. Results: As of March 29th, 2024, 69 pts received zamto-cel of which 59 were evaluable having received a fresh, conforming product and completed a minimum of 3 months follow-up. Median age was 63 years (range 25-85), 39 (66%) were male. Sixteen pts (27%) received 3 or more lines of prior treatment. The majority of pts (53%) had elevated LDH at study entry, and 49% had ≥ 2 extranodal lesions, indicative of a study population with advanced disease. No pts received any bridging therapy, in the week after apheresis and before lymphodepletion. Only 7 pts (12%) received bendamustine as lymphodepleting regimen. Successful manufacturing of a fresh, in specification product occurred in 91.3% out of 69 treated pts. Four patients received a cryopreserved formulation to permit time for comorbid condition management. The mean viability of the final product was 96.0% with 29.4 % transduction efficacy. No patient died or withdrew during the manufacturing process. The ORR in the evaluable patient population (n=59) as assessed by an Independent Radiology Committee (IRC) was 72.9% (95% CI, 59.7-83.6), with a CRR of 49.2% (95% CI,35.9-62.5). The 6 month and 12 month-PFS was 55% (95%CI, 41-67) and 42% (95%CI, 28-56), respectively; 12 month-OS was 72% (95%CI, 57-83). The median DOR was 11.4 months. All 69 treated pts were assessed for safety outcomes. Treatment-emergent adverse events (TEAEs) were mostly of grade 1-2, the majority of grade ≥ 3 were hematological. Thirty-two pts (46.4%) experienced cytokine release syndrome (CRS), all grade 1-2. Immune effector cell-associated neurotoxicity syndrome (ICANS) was reported in 12 pts (17.4%), grade 1-2 (9 pts; 13.1%); grade 3 (3 pts; 4.3%). One patient experienced immune effector cell-associated hemophagocytic lymphohistiocytosis-like syndrome (IEC-HS), which resolved after 2 days. Biopsies at progression were available in 24 pts. CD19-negative relapse (defined as H Score <100) was seen in 2 pts, CD20-negative relapse was observed in 3 pts. Only one patient experienced loss of both antigens compared to pre-treatment status, demonstrating that most lymphomas maintain target antigen expression at relapse after treatment with zamto-cel. Conclusion: This pre-planned interim analysis represents the first pivotal trial of a tandem CD20-CD19 directed non-cryopreserved CAR-T cell product for patients with third-line r/r DLBCL. The trial plans to enroll 100 evaluable patients and the final data will be presented upon study completion. Among the 59 evaluable patients at the interim analysis, there is encouraging activity and a favorable safety profile in DLBCL patients treated with zamto-cel. Unlike currently registered CAR-T cell products, zamto-cel is administered as a fresh product with a short vein-to-vein time of 14 days with lymphodepletion initiated during the manufacturing process. With a manufacturing success rate of 91% we have demonstrated the feasibility of this process among high-risk patients with r/r DLBCL.

Background: In the ZUMA2 study, a higher peak chimeric antigen receptor (CAR) T cell expansion correlated with better outcomes in patients with relapsed/refractory (R/R) mantle cell lymphoma (MCL) receiving brexucabtagene autoleucel (brexu-cel). However, in clinical practice, peak CAR T cell expansion is not routinely assessed for. Since patients receive lymphodepleting agents prior to CAR T cell infusion, it is hypothesized that peak absolute lymphocyte count (ALC), which can be easily measured, in the first two weeks after CAR T cell infusion represents peak CAR T cell expansion. Our group previously showed that peak ALC was associated with response durability and outcomes in patients with R/R large B-cell lymphoma receiving axicabtagene ciloleucel. In this retrospective study, we assessed the association of peak ALC with clinical outcomes after brexu-cel infusion in patients with R/R MCL. Methods: Patients with R/R MCL who received brexu-cel between March 2020-March 2024 at Mayo Clinic were included in this analysis. Peak ALC was defined as maximum ALC value in the first 14 days after CAR T cell infusion. Progression-free survival (PFS) was defined as time from CAR T cell infusion to lymphoma relapse, progression, or death, and overall survival (OS) was defined as time from to CAR T cell infusion to death. The optimal cutoff point for peak ALC that correlated with PFS was determined by the log-rank method using the Cutoff Finder application, a computational method which fits Cox proportional hazard models to the dichotomized variable and survival. The optimal cutoff was the point with the most significant PFS split by log-rank test. Results: A total of 43 patients were identified. The median age at time of CAR T cell infusion was 68 years (IQR 58, 73). 34 (79%) were male, 28 (74%) had Ki-67 >30%, 14 (33%) had blastoid or pleomorphic histology, and 19 (44%) had TP53 mutation or deletion. Median number of prior lines of therapy was 3 (IQR 2, 4) and 13 (30%) received prior autologous stem cell transplant. 32 (74%) received bridging therapy prior to CAR T cell infusion. All patients received fludarabine plus cyclophosphamide for lymphodepletion. The best overall response rate was 88%, with a complete response rate of 84%. After a median follow-up of 25.6 months (95% CI 14.4-31.4), the median PFS and OS were 16.6 (95% CI 8.6-NE) and 35.1 (95% CI 24.5-NE) months, respectively. The incidence of cytokine release syndrome (CRS) was 95% (4.7% grade ≥3). The median time to initial CRS and maximum grade CRS onset was 4.5 days (IQR 1, 6.25) and 5.5 days (IQR 2.75, 7), respectively. The incidence of immune effector cell-associated neurotoxicity syndrome (ICANS) was 65% (18% grade ≥ 3). The median time to initial and maximum grade ICANS onset was 9 days (IQR 6, 11) and 10.5 days (IQR 7, 12), respectively. The median ALC at time of CAR T cell infusion was 0.03 x109/L (IQR 0.02, 0.05). Among 37 patients with identifiable ALC peaks, the median ALC peak was 0.84 (IQR 0.41, 2.45) and the median time to peak ALC was 12 days (IQR 9, 12). 6 patients had no identifiable peak ALC due to no frequent CBC differentials post CAR T cell infusion. A peak ALC of ≥0.45 × 109/L correlated significantly with PFS, with median PFS not reached for the group with peak ALC of ≥0.45 × 109/L (n=27) compared to 9.3 months for the group with peak ALC of <0.45 × 109/L (n=10) and a 1-year PFS rate of 68% vs 33% (p=0.02). OS was also significantly higher in patients with a peak ALC of ≥0.45 × 109/L (median OS not reached vs 11 months, 1-year OS rate of 84% vs 44%, p=0.01). The incidence of ICANS was significantly higher (74% vs 30%, p=0.02) in patients with a peak ALC of ≥0.45 × 109/L. Numerically, the group with peak ALC of ≥0.45 × 109/L had a later onset of initial and maximum grade ICANS, but the difference was not statistically significant. Peak ALC was not associated with ICANS severity. There was a trend towards higher incidence of CRS (100% vs 80%, p=0.07) and earlier CRS onset (3 vs 5 days, p=0.07) in the high peak ALC group. There was no difference in CRS severity. Conclusion: Peak ALC after CAR T cell infusion was significantly associated with better PFS and OS and higher incidence of ICANS in patients with R/R MCL receiving brexu-cel. Peak ALC may serve as a surrogate measure for peak CAR T cell expansion in routine practice, but confirmatory studies are needed. Larger studies are warranted to confirm the association of peak ALC with PFS, OS and toxicities in patients with R/R MCL receiving brexu-cel.

Background and Methods: IEC-HS is a hyperinflammatory state with high morbidity and mortality. Effective interventions to reverse the process early in the clinical course may be critical to improve outcomes. We previously examined cytokine differences between IEC-HS and other secondary hemophagocytic lymphohistiocytosis, and found significant differences in the patterns and outcomes.(1) This study examines cytokine profiles (CP) of patients treated with CAR-T from 9/2019 to 3/2024 who developed CRS, MAS-L and IEC-HS. Demographics and lab results were compared among the three groups and correlated with outcomes. Results: CP was tested in 113 of 366 CAR-T patients: 74 with CRS, 19 with MAS-L, and 20 with IEC-HS. The racial distribution was 93% White/Caucasian, 2% Black or African American, 1% Asian, 1% Native American and 3% other or unavailable. No differences were seen in demographics between groups except a higher percentage of patients with ECOG performance status ≥2 in IEC-HS (p=0.037). Incidence of IEC-HS by disease: 3.6% (7/193) in lymphoma, 5% (8/159) myeloma and 28.5% (4/14) B-acute lymphoblastic leukemia (p=0.0002). Incidence of IEC-HS by CAR-T product: 3% (4/150) in Axi-cel, 23% (6/26) in Brexu-cel, 8% (1/13) in Tisa-cel, 5% each (3/60) in Cilta-cel and Ide-cel, and 0/17 in Liso-cel (p=0.001). Prior to lymphodepletion, labs were already different among the CRS, MAS-L, and IEC-HS groups: hemoglobin (g/dL: 11.1, 9.6, 8.45); platelets (x109/L: 168, 116, 52.5); ferritin (µg/L: 115, 946, 1944). CP was started when patients needed a second dose of tocilizumab or concern for developing MAS-L/IEC-HS, and continued daily until clinical improvement or resolution of inflammatory state. Tocilizumab and dexamethasone use were similar across groups. Other therapies used were vasopressors (3%, 10.5%, 45%; p<0.0001), Methylprednisolone (20%, 31.6%, 50%; p=0.027), Anakinra (12%, 63%, 85%; p<0.0001), Siltuximab (9.5%, 16%, 30%; p=0.06), Basiliximab (30% of IEC-HS), and continuous veno-venous hemofiltration (30% of IEC-HS). Among the first CP, the CRS group had lower levels of cytokines (in pg/mL) compared to MAS-L and IEC-HS groups: TNF (31, 62.9, 47.7), IL-10 (29.3, 97.7, 169), IL-18 (794, 1353, 2011), IFN-gamma (74, 281, 250), MCP-1 (689, 2722, 2485.5), MIP-1 alpha (220, 234, 247.5), IL-6 (>315: 45%, 79%, 70%), soluble IL-2R alpha (>4000: 45%, 84%, 70%). The percentage of patients who received anakinra before CP1 were 4% (CRS), 21% (MAS-L) and 25% (IEC-HS) (p=0.007). IL-1 beta was below threshold among all patients who received anakinra in CRS and MAS-L and 75% in IEC-HS, suggesting rapid and effective IL-1 suppression by anakinra except in IEC-HS. Cytokines trends 24 hours and 48 hours after the first CP differed between MAS-L and IEC-HS. MAS-L had decreased TNF (62.9, 40.4, 18.5) and MCP-1 (2722, 355, 104) while these cytokines remained elevated or increased in IEC-HS (TNF: 47.7, 105.5, 62.6; MCP-1: 2486, 2276, 1585). IL-18 was minimally elevated in MAS-L (1353, 1955, 3068) and significantly increased in IEC-HS (2011, 2420, 4048). Notably, CP2 and CP3 levels of these cytokines in IEC-HS were statistically significantly higher than corresponding CPs among CRS and MAS-L. In addition, patients who died with persistent E. faecium bacteremia had higher IL-18 on CP3. Infections occurred in 43%, 58%, and 85% respectively (p=0.002), including E. faecium bacteremia (3%, 5%, 35%; p=0.0004), CMV viremia (30% of IEC-HS patients vs. 11% of non-IEC-HS; p=0.025), and invasive fungal infections (15% of IEC-HS patients; p=0.0001). Between the IEC-HS and non-IEC-HS groups, day 100 non-relapse mortality was 35% vs. 0 (p<0.0001), day 100 all-cause mortality was 45% vs. 3% (p<0.0001), and E. faecium bacteremia-related deaths were 50% vs. 1% (p<0.0001). Conclusions: CRS, MAS-L andIEC-HS are known complications of CAR-T. Cytokine-directed therapy can modify the cytokine milieu and control the inflammatory process. However, excess immunosuppression may result in life-threatening infections. Further studies are needed to identify optimal biomarker-guided immunosuppressive strategies to control the inflammatory cascade, while avoiding excess immunosuppression. References: 1. Leung, Nelson, et al. “Outcomes of patients who received CAR T cell therapy and developed IEC-HS treated with cytokine directed therapy.” (2024): 7516-7516.