The CNS Relapse in T-Cell Lymphoma Index Predicts CNS Relapse in Patients with T- and NK-Cell Lymphomas

Little is known about risk factors for central nervous system (CNS) relapse in mature T- and NK-cell neoplasms (MTNKN). We aimed to describe the clinical epidemiology of CNS relapse in patients with MTNKN and developed the CNS relapse In T-cell lymphoma Index (CITI) to predict patients at highest risk of CNS relapse. We reviewed data from 135 patients with MTNKN and CNS relapse from 19 North American institutions. After exclusion of leukemic and most cutaneous forms of MTNKN, patients were pooled with non-CNS relapse control patients from a single institution to create a CNS relapse-enriched training set. Using a complete case analysis (N=182), of whom 91 had CNS relapse, we applied a LASSO Cox regression model to select weighted clinicopathologic variables for the CITI score, which we validated in an external cohort from the Swedish Lymphoma Registry (N=566). CNS relapse was most frequently observed in patients with PTCL, NOS (25%). Median time to CNS relapse and median overall survival after CNS relapse was 8.0 months and 4.7 months, respectively. We calculated unique CITI risk scores for individual training set patients and stratified them into risk terciles. Validation set patients with low-risk (N=158) and high-risk (N=188) CITI scores had a 10-year cumulative risk of CNS relapse of 2.2% and 13.4%, respectively (HR 5.24, 95%CI 1.50-18.26, P=0.018). We developed an open-access web-based CITI calculator (https://redcap.link/citicalc) to provide an easy tool for clinical practice. The CITI score is a validated model to predict patients with MTNKN at highest risk of developing CNS relapse.

Durable response after tisagenlecleucel in adults with relapsed/refractory follicular lymphoma: ELARA trial update

ABSTRACT

Tisagenlecleucel is approved for adults with relapsed/refractory (r/r) follicular lymphoma (FL) in the third- or later-line setting. The primary analysis (median follow-up, 17 months) of the phase 2 ELARA trial reported high response rates and excellent safety profile in patients with extensively pretreated r/r FL. Here, we report longer-term efficacy, safety, pharmacokinetic, and exploratory biomarker analyses after median follow-up of 29 months (interquartile range, 22.2-37.7). As of 29 March 2022, 97 patients with r/r FL (grades 1-3A) received tisagenlecleucel infusion (0.6 × 108-6 × 108 chimeric antigen receptor-positive viable T cells). Bridging chemotherapy was allowed. Baseline clinical factors, tumor microenvironment, blood soluble factors, and circulating blood cells were correlated with clinical response. Cellular kinetics were assessed by quantitative polymerase chain reaction. Median progression-free survival (PFS), duration of response (DOR), and overall survival (OS) were not reached. Estimated 24-month PFS, DOR, and OS rates in all patients were 57.4% (95% confidence interval [CI], 46.2-67), 66.4% (95% CI, 54.3-76), and 87.7% (95% CI, 78.3-93.2), respectively. Complete response rate and overall response rate were 68.1% (95% CI, 57.7-77.3) and 86.2% (95% CI, 77.5-92.4), respectively. No new safety signals or treatment-related deaths were reported. Low levels of tumor-infiltrating LAG3+CD3+ exhausted T cells and higher baseline levels of naïve CD8+ T cells were associated with improved outcomes. Tisagenlecleucel continued to demonstrate highly durable efficacy and a favorable safety profile in this extended follow-up of 29 months in patients with r/r FL enrolled in ELARA. This trial was registered at www.clinicaltrials.gov as #NCT03568461.

Efficacy and safety of bendamustine for lymphodepletion before lisocabtagene maraleucel

Bendamustine has been retrospectively shown to be an effective and safe lymphodepletion regimen prior to the anti-CD19 chimeric antigen receptor T cell (CART) products tisagenlecleucel and axicabtagene ciloleucel, as well as the anti-BCMA CART products idecabtagene vicleucel and ciltacabtagene autoleucel. However, bendamustine as lymphodepletion prior to lisocabtagene maraleucel (liso-cel), a 4-1BB co-stimulated, fixed CD4:CD8 ratio anti-CD19 CART product, has not been described yet. Thus, we studied a cohort of sequentially-treated patients with large B-cell lymphomas who received bendamustine lymphodepletion before liso-cel at the University of Pennsylvania between 5/2021 and 12/2023 (n = 31). Patients were evaluated for toxicities and responses. Of note, 7 patients (22.6%) would have dnot met the inclusion criteria for the registrational liso-cel clinical trials, mostly due to older age. Overall and complete response rates were 76.9% and 73.1%, respectively. At a median follow-up of 6.3 months, the 6-month progression-free and overall survival were 59.9% and 91.1%, respectively. Rates of cytokine-release syndrome (CRS) and neurotoxicity (ICANS) of any grade were 9.7% and 9.7%, respectively, with no grade ≥ 3 events. No infections were reported during the first 30 days following liso-cel infusion. Neutropenia ≥ grade 3 was observed in 29.0% of patients; thrombocytopenia ≥ grade 3 occurred in 9.7%. In conclusion, bendamustine lymphodepletion before liso-cel appears to be a strategy that can drive tumor responses while ensuring a mild toxicity profile.

T cell lymphoma and secondary primary malignancy risk after commercial CAR T cell therapy

We report a T cell lymphoma (TCL) occurring 3 months after anti-CD19 chimeric antigen receptor (CAR) T cell immunotherapy for non-Hodgkin B cell lymphoma. The TCL was diagnosed from a thoracic lymph node upon surgery for lung cancer. The TCL exhibited CD8+ cytotoxic phenotype and a JAK3 variant, while the CAR transgene was very low. The T cell clone was identified at low levels in the blood before CAR T infusion and in lung cancer. To assess the overall risk of secondary primary malignancy after commercial CAR T (CD19, BCMA), we analyzed 449 patients treated at the University of Pennsylvania. At a median follow-up of 10.3 months, 16 patients (3.6%) had a secondary primary malignancy. The median onset time was 26.4 and 9.7 months for solid and hematological malignancies, respectively. The projected 5-year cumulative incidence is 15.2% for solid and 2.3% for hematological malignancies. Overall, one case of TCL was observed, suggesting a low risk of TCL after CAR T.

Bendamustine as Lymphodepletion for Brexucabtagene Autoleucel Therapy of Mantle Cell Lymphoma

Brexucabtagene autoleucel (brexu-cel) is an autologous CD19-directed chimeric antigen receptor (CAR) T-cell therapy approved for treatment of relapsed/refractory mantle cell lymphoma (MCL). During a fludarabine shortage, we used bendamustine as an alternative to standard cyclophosphamide/fludarabine (cy/flu) lymphodepletion (LD) prior to brexu-cel. We assessed MCL patient outcomes as well as CAR T-cell expansion and persistence after brexu-cel following bendamustine or cy/flu LD at our center. This was a retrospective single institution study that utilized prospectively banked blood and tissue samples. Clinical efficacy was assessed by 2014 Lugano guidelines. CAR T-cell expansion and persistence in peripheral blood were assessed on day 7 and at ≥month 6 for patients with available samples. Seventeen patients received bendamustine and 5 received cy/flu. For the bendamustine cohort, 14 (82%) received bridging therapy and 4 (24%) had CNS involvement. Fifteen patients (88%) developed CRS with 4 (24%) ≥grade 3 events. Six (35%) patients developed ICANS with 4 (24%) events ≥grade 3. No patient had ≥grade 3 cytopenias at day 90. Best objective (BOR) and complete response (CRR) rates were 82% and 65%, respectively. At 24.5 months median follow-up, 12-month progression-free survival (PFS) was 45%, 24-month PFS was 25%, and median duration of response was 19 months. Median OS was not reached. BOR was 25% (1/4) for patients with CNS involvement. CAR transgene expansion after bendamustine LD was observed on day 7 in all (4/4) patients tested and persisted at ≥6 months (2/2), regardless of response. Bendamustine LD before brexu-cel for MCL is feasible and safe with a lower frequency and shorter duration of cytopenias than reported for cy/flu. Both CAR T-cell expansion and persistence were observed after bendamustine LD. Outcomes appear comparable to the real world outcomes reported with cy/flu LD.

Immunologic predictors of vaccine responsiveness in patients with lymphoma and CLL

Patients with B-cell lymphomas have altered cellular components of vaccine responses due to malignancy and therapy, and the optimal timing of vaccination relative to therapy remains unknown. SARS-CoV-2 vaccines created an opportunity for new insights in vaccine timing because patients were challenged with a novel antigen across multiple phases of treatment. We studied serologic mRNA vaccine response in retrospective and prospective cohorts with lymphoma and CLL, paired with clinical and research immune parameters. Reduced serologic response was observed more frequently during active therapies, but non-response was also common within observation and post-treatment groups. Total IgA and IgM correlated with successful vaccine response. In individuals treated with CART-19, non-response was associated with reduced B and T follicular helper cells. Predictors of vaccine response varied by disease and therapeutic group, and therefore further studies of immune health during and after cancer therapies are needed to allow individualized vaccine timing.

Long-Term Follow-Up of the RESORT Study (E4402): A Randomized Phase III Comparison of Two Different Rituximab Dosing Strategies for Low-Tumor Burden Follicular Lymphoma

Clinical trials frequently include multiple end points that mature at different times. The initial report, typically based on the primary end point, may be published when key planned co-primary or secondary analyses are not yet available. Clinical trial updates provide an opportunity to disseminate additional results from studies, published in JCO or elsewhere, for which the primary end point has already been reported.In 2003, the Eastern Cooperative Oncology Group initiated a randomized phase III clinical trial (E4402) comparing two different rituximab dosing strategies for patients with previously untreated low-tumor burden follicular lymphoma. Rituximab-responsive patients (n = 299) were randomly assigned to either a retreatment rituximab (RR) strategy or a maintenance rituximab (MR) strategy. Each dosing strategy was continued until treatment failure. The primary end point of the study was time to treatment failure (TTF). In the original report, there was no difference in TTF between the two dosing strategies. Here, we report on the long-term outcomes for secondary end points of time to first cytotoxic therapy, duration of response, and overall survival (OS). At 7 years, 83% of MR patients had not required first chemotherapy compared with 63% of RR patients (hazard ratio, 2.37 [95% CI, 1.5 to 3.76]). At 7 years, 71% of MR remained in their first remission compared with 37% of RR patients. Despite the improved first remission length with MR, there was no difference in OS at 10 years (83% v 84%). With mature long-term data, we confirm that prolonged maintenance rituximab does not confer an OS advantage in low-tumor burden follicular lymphoma.

Comparative efficacy and safety of tisagenlecleucel and axicabtagene ciloleucel among adults with r/r follicular lymphoma

Regulatory approvals of tisagenlecleucel (tisa-cel) and axicabtagene ciloleucel (axi-cel) have established the feasibility of chimeric antigen receptor T-cell therapies for the treatment of adults with relapsed or refractory follicular lymphoma (r/r FL). This study used individual patient data from ELARA (tisa-cel) and aggregate published patient data from ZUMA-5 (axi-cel) to compare efficacy and safety outcomes in r/r FL using matching-adjusted indirect comparison methods. After adjustment for baseline differences in the trial populations, the results suggested that tisa-cel (n = 52), compared with axi-cel (n = 86), had similar effects on overall response rate (91.2% vs. 94.2%; p = .58), complete response rate (74.0% vs. 79.1%; p = .60), progression-free survival (HR [95% CI]: 0.8 [0.4, 1.9]; p = .67), and overall survival (HR [95% CI]: 0.5 [0.2, 1.5]; p = .21). Tisa-cel (n = 53) was associated with better safety outcomes than axi-cel (n = 124), reflected by lower rates of any grade and grade ≥3 cytokine release syndrome and neurological events.

Loss of CD20 expression as a mechanism of resistance to mosunetuzumab in relapsed/refractory B-cell lymphomas

ABSTRACT

CD20 is an established therapeutic target in B-cell malignancies. The CD20 × CD3 bispecific antibody mosunetuzumab has significant efficacy in B-cell non-Hodgkin lymphomas (NHLs). Because target antigen loss is a recognized mechanism of resistance, we evaluated CD20 expression relative to clinical response in patients with relapsed and/or refractory NHL in the phase 1/2 GO29781 trial investigating mosunetuzumab monotherapy. CD20 was studied using immunohistochemistry (IHC), RNA sequencing, and whole-exome sequencing performed centrally in biopsy specimens collected before treatment at predose, during treatment, or upon progression. Before treatment, most patients exhibited a high proportion of tumor cells expressing CD20; however, in 16 of 293 patients (5.5%) the proportion was <10%. Analyses of paired biopsy specimens from patients on treatment revealed that CD20 levels were maintained in 29 of 30 patients (97%) vs at progression, where CD20 loss was observed in 11 of 32 patients (34%). Reduced transcription or acquisition of truncating mutations explained most but not all cases of CD20 loss. In vitro modeling confirmed the effects of CD20 variants identified in clinical samples on reduction of CD20 expression and missense mutations in the extracellular domain that could block mosunetuzumab binding. This study expands the knowledge about the occurrence of target antigen loss after anti-CD20 therapeutics to include CD20-targeting bispecific antibodies and elucidates mechanisms of reduced CD20 expression at disease progression that may be generalizable to other anti-CD20 targeting agents. These results also confirm the utility of readily available IHC staining for CD20 as a tool to inform clinical decisions. This trial was registered at www.ClinicalTrials.gov as #NCT02500407.

Bendamustine lymphodepletion before axicabtagene ciloleucel is safe and associates with reduced inflammatory cytokines

ABSTRACT

Lymphodepletion (LD) is an integral component of chimeric antigen receptor T-cell (CART) immunotherapies. In this study, we compared the safety and efficacy of bendamustine (Benda) to standard fludarabine/cyclophosphamide (Flu/Cy) LD before CD19-directed, CD28-costimulated CART axicabtagene ciloleucel (axi-cel) for patients with large B-cell lymphoma (LBCL) and follicular lymphoma (FL). We analyzed 59 patients diagnosed with LBCL (n = 48) and FL (n = 11) consecutively treated with axi-cel at the University of Pennsylvania. We also analyzed serum samples for cytokine levels and metabolomic changes before and after LD. Flu/Cy and Benda demonstrated similar efficacy, with complete remission rates of 51.4% and 50.0% (P = .981), respectively, and similar progression-free and overall survivals. Any-grade cytokine-release syndrome occurred in 91.9% of patients receiving Flu/Cy vs 72.7% of patients receiving Benda (P = .048); any-grade neurotoxicity after Flu/Cy occurred in 45.9% of patients and after Benda in 18.2% of patients (P = .031). In addition, Flu/Cy was associated with a higher incidence of grade ≥3 neutropenia (100% vs 54.5%; P < .001), infections (78.4% vs 27.3%; P < .001), and neutropenic fever (78.4% vs 13.6%; P < .001). These results were confirmed both in patients with LBCL and those with FL. Mechanistically, patients with Flu/Cy had a greater increase in inflammatory cytokines associated with neurotoxicity and reduced levels of metabolites critical for redox balance and biosynthesis. This study suggests that Benda LD may be a safe alternative to Flu/Cy for CD28-based CART CD19-directed immunotherapy with similar efficacy and reduced toxicities. Benda is associated with reduced levels of inflammatory cytokines and increased anabolic metabolites.

TP53 mutations predict for poor outcomes in patients with newly diagnosed aggressive B-cell lymphomas in the current era

Genetic subgroups of diffuse large B-cell lymphoma (DLBCL) have been identified through comprehensive genomic analysis; however, it is unclear whether this can be applied in clinical practice. We assessed whether mutations detected by clinical laboratory mutation analysis (CLMA) were predictive of outcomes in patients with newly diagnosed DLBCL/high-grade B-cell lymphoma (HGBL). Patients diagnosed from 2018 to 2022 whose biopsy samples were subjected to CLMA and who received rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone or rituximab plus etoposide, prednisolone, vincristine, cyclophosphamide, and doxorubicin were analyzed for overall/complete response rate (ORR/CRR) and estimated progression-free/overall survival (PFS/OS). CLMA was successfully performed in 117 of 122 patient samples (96%), with a median turnaround time of 17 days. Median duration of follow-up was 31.3 months. Of the mutations detected in ≥10% of the samples, only TP53 was associated with both progression and death at 2 years. TP53 mutations were detected in 36% of tumors, and patients with TP53 mutations experienced significantly lower ORR (71% vs 90%; P = .009), CRR (55% vs 77%; P = .01), 2-year PFS (57% vs 77%; P = .006), 2-year OS (70% vs 91%; P = .001), and median OS after relapse (6.1 months vs not yet reached; P = .001) as than those without TP53 mutations. Furthermore, patients with TP53 loss-of-function (LOF) mutations experienced lower rates of 2-year PFS/OS than those with non-LOF mutations and inferior or near-inferior 2-year PFS if harboring high-risk clinicopathologic features. TP53 mutations identified through CLMA can predict for inferior outcomes in patients with newly diagnosed DLBCL/HGBL. Results of CLMA can be used in real time to inform prognosis and/or identify candidates for clinical trials.

Alternative splicing of its 5'-UTR limits CD20 mRNA translation and enables resistance to CD20-directed immunotherapies

Aberrant skipping of coding exons in CD19 and CD22 compromises the response to immunotherapy in B-cell malignancies. Here, we showed that the MS4A1 gene encoding human CD20 also produces several messenger RNA (mRNA) isoforms with distinct 5' untranslated regions. Four variants (V1-4) were detected using RNA sequencing (RNA-seq) at distinct stages of normal B-cell differentiation and B-lymphoid malignancies, with V1 and V3 being the most abundant. During B-cell activation and Epstein-Barr virus infection, redirection of splicing from V1 to V3 coincided with increased CD20 positivity. Similarly, in diffuse large B-cell lymphoma, only V3, but not V1, correlated with CD20 protein levels, suggesting that V1 might be translation-deficient. Indeed, the longer V1 isoform contained upstream open reading frames and a stem-loop structure, which cooperatively inhibited polysome recruitment. By modulating CD20 isoforms with splice-switching morpholino oligomers, we enhanced CD20 expression and anti-CD20 antibody rituximab-mediated cytotoxicity in a panel of B-cell lines. Furthermore, reconstitution of CD20-knockout cells with V3 mRNA led to the recovery of CD20 positivity, whereas V1-reconstituted cells had undetectable levels of CD20 protein. Surprisingly, in vitro CD20-directed chimeric antigen receptor T cells were able to kill both V3- and V1-expressing cells, but the bispecific T-cell engager mosunetuzumab was only effective against V3-expressing cells. To determine whether CD20 splicing is involved in immunotherapy resistance, we performed RNA-seq on 4 postmosunetuzumab follicular lymphoma relapses and discovered that in 2 of them, the downregulation of CD20 was accompanied by a V3-to-V1 shift. Thus, splicing-mediated mechanisms of epitope loss extend to CD20-directed immunotherapies.

Nine-year follow-up of lenalidomide plus rituximab as initial treatment for mantle cell lymphoma

Although chemoimmunotherapy is the current standard of care for initial treatment of mantle cell lymphoma (MCL), newer data suggest that there may be a role for a chemotherapy-free approach. We report the 9-year follow-up results of a multicenter, phase 2 study of lenalidomide plus rituximab (LR) as the initial treatment of MCL. The LR doublet is used as induction and maintenance until progression, with optional discontinuation after 3 years. We previously reported an overall response rate of 92% in evaluable patients, with 64% achieving a complete response. At a median follow-up of 103 months, 17 of 36 evaluable patients (47%) remain in remission. The 9-year progression-free survival and overall survival were 51% and 66%, respectively. During maintenance, hematologic adverse events included asymptomatic grade 3 or 4 cytopenia (42% neutropenia, 5% thrombocytopenia, and 3% anemia) and mostly grade 1 to 2 infections managed in the outpatient setting (50% upper respiratory infections, 21% urinary tract infections, 16% sinusitis, 16% cellulitis, and 13% pneumonia, with 5% requiring hospitalization). More patients developed grade 1 and 2 neuropathy during maintenance therapy (29%) than during induction therapy (8%). Twenty-one percent of patients developed secondary malignancies, including 5% with invasive malignancies, whereas the remainder were noninvasive skin cancers treated with local skin-directed therapy. Two patients permanently discontinued therapy because of concerns of immunosuppression during the COVID-19 pandemic. With long-term follow-up, LR continues to demonstrate prolonged, durable responses with manageable safety as initial induction therapy. This trial was registered at www.clinicaltrials.gov as #NCT01472562.

Identifying an optimal fludarabine exposure for improved outcomes after axi-cel therapy for aggressive B-cell non-Hodgkin lymphoma

Fludarabine is one of the most common agents given for lymphodepletion before CD19 chimeric antigen receptor T cells, but its optimal therapeutic intensity is unknown. Using data from a multicenter consortium, we estimated fludarabine exposure (area under the curve [AUC]) using a population pharmacokinetic (PK) model in 199 adult patients with aggressive B-cell non-Hodgkin lymphomas who received commercial axicabtagene ciloleucel (Axi-cel). We evaluated the association of estimated fludarabine AUC with key outcomes, aiming to find an AUC that optimized efficacy and tolerability. We identified low (<18 mg × hour/L [mgh/L]), optimal (18-20 mgh/L), and high (>20 mgh/L) AUC groups for analyses; the 6-month cumulative incidences of relapse/progression of disease (relapse/POD) by AUC groups were 54% (45%-62%), 28% (15%-44%), and 30% (14%-47%), respectively; and the 1-year progression-free survival (PFS) rates were 39% (31%-48%), 66% (52%-84%), and 46% (30%-70%) and the overall survival (OS) rates were 58% (50%-67%), 77% (64%-92%), and 66% (50%-87%), respectively. In multivariable analyses compared with low AUC, an optimal AUC was associated with the highest PFS (hazard ratio [HR], 0.52; 0.3-0.91; P = .02) and lowest risk of relapse/POD (HR, 0.46; 0.25-0.84; P = .01) without an increased risk of any-grade cytokine release syndrome (HR, 1.1; 0.7-1.6; P = .8) or and immune effector cell-associated neurotoxicity syndrome (ICANS) (HR, 1.36; 0.83-2.3; P = .2). A high AUC was associated with the greatest risk of any-grade ICANS (HR, 1.9; 1.1-3.2; P = .02). Although the main cause of death in all groups was relapse/POD, nonrelapse-related deaths, including 3 deaths from ICANS, were more frequent in the high AUC group. These findings suggest that PK-directed fludarabine dosing to achieve an optimal AUC may result in improved outcomes for patients receiving axi-cel.

Mosunetuzumab monotherapy is active and tolerable in patients with relapsed/refractory diffuse large B-cell lymphoma

As part of a phase 1 or 2 study, this single-arm expansion cohort established the efficacy and safety of mosunetuzumab monotherapy in patients with relapsed/refractory (R/R) diffuse large B-cell lymphoma (DLBCL) (received ≥2 previous lines of therapy). Intravenous mosunetuzumab was administered with cycle (C) 1 step-up dosing for cytokine release syndrome (CRS) mitigation: C1 day (D) 1: 1 mg; C1D8 2 mg; C1D15 and C2D1: 60 mg; C3 + D1: 30 mg. Hospitalization was not mandatory. Patients with complete response (CR) completed treatment after C8; those with partial response or stable disease continued treatment for a total of 17 cycles. The primary end point was CR rate (best response), assessed against a historical control CR rate (20%) by independent review facility. Eighty-eight patients (73.9% de novo DLBCL; 26.1% transformed follicular lymphoma) were enrolled; all had received previous anthracycline and anti-CD20 therapy. Overall response and CR rates were 42.0% (95% confidence interval [CI], 31.6-53.1) and 23.9% (95% CI, 15.4-34.1), respectively; CR rate did not reach statistical significance vs the historical control (P = .36). Median time to first response was 1.4 months. Median progression-free survival was 3.2 months (95% CI, 2.2-5.3). The CR rate in 26 patients who received previous chimeric antigen receptor T-cell (CAR-T) therapy was 12%. CRS was one of the most common adverse events (26.1% of patients); predominantly grade 1 to 2 and primarily in C1. Four patients (4.5%) discontinued mosunetuzumab owing to adverse events. Mosunetuzumab demonstrated notable efficacy and a manageable safety profile in patients with R/R DLBCL, including those previously treated with CAR-Ts. This trial was registered at www.clinicaltrials.gov as #NCT02500407.

Chimeric antigen receptor T-cell therapy yields similar outcomes in patients with and without cytokine release syndrome

Chimeric antigen receptor (CAR) T-cell therapy has revolutionized the treatment of many patients with aggressive relapsed or refractory large B-cell lymphoma (LBCL). Treatment can be complicated by clinically evident cytokine release syndrome (CRS), which is characterized by the development of fever, hypoxia, and hypotension, and can be life-threatening. Most patients treated with CAR-T cells develop CRS, which is thought to represent an immune phenomenon. It was previously unknown whether patients who did not develop CRS had reduced CAR-T cell activity and were therefore likely to have worse outcomes. We conducted a multicenter retrospective analysis of 352 adult patients treated at 8 academic medical centers in the United States who received axicabtagene ciloleucel or tisagenlecleucel for the treatment of LBCL. The outcomes of interest included progression-free survival, overall survival, complete response rate, and overall response rate. Of the included patients, 262 (74.4%) developed CRS. There was no significant difference in progression-free survival (P = .99) or overall survival (P = .16) between patients who developed CRS and those who did not develop CRS. Peak ferritin levels >5000 ng/mL during treatment and lactate dehydrogenase levels greater than the institutional upper limit of normal before lymphodepleting chemotherapy were associated with significantly worse progression-free and overall survival in the multivariate analysis. There was no significant difference in the complete response or overall response rates between patients who did and did not develop CRS. In this retrospective analysis, we report that patients who develop CRS have clinical outcomes similar to those of patients without CRS treated with commercial anti-CD19 CAR-T cells.

Lisocabtagene maraleucel in chronic lymphocytic leukaemia and small lymphocytic lymphoma (TRANSCEND CLL 004): a multicentre, open-label, single-arm, phase 1-2 study

BACKGROUND

Patients with relapsed or refractory chronic lymphocytic leukaemia or small lymphocytic lymphoma for whom treatment has failed with both Bruton tyrosine kinase (BTK) inhibitor and venetoclax have few treatment options and poor outcomes. We aimed to evaluate the efficacy and safety of lisocabtagene maraleucel (liso-cel) at the recommended phase 2 dose in patients with relapsed or refractory chronic lymphocytic leukaemia or small lymphocytic lymphoma.

METHODS

We report the primary analysis of TRANSCEND CLL 004, an open-label, single-arm, phase 1-2 study conducted in the USA. Patients aged 18 years or older with relapsed or refractory chronic lymphocytic leukaemia or small lymphocytic lymphoma and at least two previous lines of therapy, including a BTK inhibitor, received an intravenous infusion of liso-cel at one of two target dose levels: 50 × 106 (dose level 1) or 100 × 106 (dose level 2, DL2) chimeric antigen receptor-positive T cells. The primary endpoint was complete response or remission (including with incomplete marrow recovery), assessed by independent review according to the 2018 International Workshop on Chronic Lymphocytic Leukemia criteria, in efficacy-evaluable patients with previous BTK inhibitor progression and venetoclax failure (the primary efficacy analysis set) at DL2 (null hypothesis of ≤5%). This trial is registered with ClinicalTrials.gov, NCT03331198.

FINDINGS

Between Jan 2, 2018, and June 16, 2022, 137 enrolled patients underwent leukapheresis at 27 sites in the USA. 117 patients received liso-cel (median age 65 years [IQR 59-70]; 37 [32%] female and 80 [68%] male; 99 [85%] White, five [4%] Black or African American, two [2%] other races, and 11 [9%] unknown race; median of five previous lines of therapy [IQR 3-7]); all 117 participants had received and had treatment failure on a previous BTK inhibitor. A subset of patients had also experienced venetoclax failure (n=70). In the primary efficacy analysis set at DL2 (n=49), the rate of complete response or remission (including with incomplete marrow recovery) was statistically significant at 18% (n=9; 95% CI 9-32; p=0·0006). In patients treated with liso-cel, grade 3 cytokine release syndrome was reported in ten (9%) of 117 (with no grade 4 or 5 events) and grade 3 neurological events were reported in 21 (18%; one [1%] grade 4, no grade 5 events). Among 51 deaths on the study, 43 occurred after liso-cel infusion, of which five were due to treatment-emergent adverse events (within 90 days of liso-cel infusion). One death was related to liso-cel (macrophage activation syndrome-haemophagocytic lymphohistiocytosis).

INTERPRETATION

A single infusion of liso-cel was shown to induce complete response or remission (including with incomplete marrow recovery) in patients with relapsed or refractory chronic lymphocytic leukaemia or small lymphocytic lymphoma, including patients who had experienced disease progression on a previous BTK inhibitor and venetoclax failure. The safety profile was manageable.

FUNDING

Juno Therapeutics, a Bristol-Myers Squibb Company.

Alternative splicing of its 5'-UTR limits CD20 mRNA translation and enables resistance to CD20-directed immunotherapies

Aberrant skipping of coding exons in CD19 and CD22 compromises responses to immunotherapy for B-cell malignancies. Here, we show that the MS4A1 gene encoding human CD20 also produces several mRNA isoforms with distinct 5' untranslated regions (5'-UTR). Four variants (V1-4) were detectable by RNA-seq in distinct stages of normal B-cell differentiation and B-lymphoid malignancies, with V1 and V3 being the most abundant by far. During B-cell activation and Epstein-Barr virus infection, redirection of splicing from V1 to V3 coincided with increased CD20 positivity. Similarly, in diffuse large B-cell lymphoma only V3, but not V1, correlated with CD20 protein levels, suggesting that V1 might be translation-deficient. Indeed, the longer V1 isoform was found to contain upstream open reading frames (uORFs) and a stem-loop structure, which cooperatively inhibited polysome recruitment. By modulating CD20 isoforms with splice-switching Morpholino oligomers, we enhanced CD20 expression and anti-CD20 antibody rituximab-mediated cytotoxicity in a panel of B-cell lines. Furthermore, reconstitution of CD20-knockout cells with V3 mRNA led to the recovery of CD20 positivity, while V1-reconstituted cells had undetectable levels of CD20 protein. Surprisingly, in vitro CD20-directed CAR T cells were able to kill both V3- and V1-expressing cells, but the bispecific T cell engager mosunetuzumab was only effective against V3-expressing cells. To determine whether CD20 splicing is involved in immunotherapy resistance, we performed RNA-seq on four post-mosunetuzumab follicular lymphoma relapses and discovered that in two of them downregulation of CD20 was accompanied by the V3-to-V1 shift. Thus, splicing-mediated mechanisms of epitope loss extend to CD20-directed immunotherapies.

Key Points

In normal & malignant human B cells, CD20 mRNA is alternatively spliced into four 5'-UTR isoforms, some of which are translation-deficient.The balance between translation-deficient and -competent isoforms modulates CD20 protein levels & responses to CD20-directed immunotherapies.

Explanation of Novelty

We discovered that in normal and malignant B-cells, CD20 mRNA is alternatively spliced to generate four distinct 5'-UTRs, including the longer translation-deficient V1 variant. Cells predominantly expressing V1 were still sensitive to CD20-targeting chimeric antigen receptor T-cells. However, they were resistant to the bispecific anti-CD3/CD20 antibody mosunetuzumab, and the shift to V1 were observed in CD20-negative post-mosunetuzumab relapses of follicular lymphoma.

Prediction of lymphoma response to CAR T cells by deep learning-based image analysis

Clinical prognostic scoring systems have limited utility for predicting treatment outcomes in lymphomas. We therefore tested the feasibility of a deep-learning (DL)-based image analysis methodology on pre-treatment diagnostic computed tomography (dCT), low-dose CT (lCT), and 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) images and rule-based reasoning to predict treatment response to chimeric antigen receptor (CAR) T-cell therapy in B-cell lymphomas. Pre-treatment images of 770 lymph node lesions from 39 adult patients with B-cell lymphomas treated with CD19-directed CAR T-cells were analyzed. Transfer learning using a pre-trained neural network model, then retrained for a specific task, was used to predict lesion-level treatment responses from separate dCT, lCT, and FDG-PET images. Patient-level response analysis was performed by applying rule-based reasoning to lesion-level prediction results. Patient-level response prediction was also compared to prediction based on the international prognostic index (IPI) for diffuse large B-cell lymphoma. The average accuracy of lesion-level response prediction based on single whole dCT slice-based input was 0.82+0.05 with sensitivity 0.87+0.07, specificity 0.77+0.12, and AUC 0.91+0.03. Patient-level response prediction from dCT, using the "Majority 60%" rule, had accuracy 0.81, sensitivity 0.75, and specificity 0.88 using 12-month post-treatment patient response as the reference standard and outperformed response prediction based on IPI risk factors (accuracy 0.54, sensitivity 0.38, and specificity 0.61 (p = 0.046)). Prediction of treatment outcome in B-cell lymphomas from pre-treatment medical images using DL-based image analysis and rule-based reasoning is feasible. This approach can potentially provide clinically useful prognostic information for decision-making in advance of initiating CAR T-cell therapy.

Low toxicity and excellent outcomes in patients with DLBCL without residual lymphoma at the time of CD19 CAR T-cell therapy

CD19 chimeric antigen receptor (CAR) T-cell therapy represents a breakthrough for patients with relapsed/refractory (R/R) diffuse large B-cell lymphoma (DLBCL), inducing sustained remissions in these patients. However, CAR T cells can result in significant toxicities. Preinfusion disease burden is associated with toxicities and outcomes after CAR T-cell therapy. We identified 33 patients with R/R DLBCL treated at 8 academic centers who had no detectable disease at the time of CAR T-cell therapy. The median time from leukapheresis to CAR T-cell infusion was 48 (19-193) days. Nine patients received axicabtagene ciloleucel, and 24 received tisagenlecleucel. There was no severe (grade ≥3) cytokine release syndrome, and only 1 patient developed severe neurotoxicity (grade 4). After a median follow-up of 16 months, 13 patients relapsed (39.4%) and 6 died (18.1%). One-year event-free survival and overall survival were 59.6% and 81.3%, respectively. Our findings suggest that, in patients with R/R DLBCL who have an indication for CAR T-cell therapy, treating patients in complete remission at the time of infusion is feasible, safe, and associated with favorable disease control. Further exploration in a larger clinical trial setting is warranted.

Survival outcomes for patients with relapsed/refractory aggressive B cell lymphomas following receipt of high dose chemotherapy/autologous stem transplantation and/or chimeric antigen receptor-modified T cells

BACKGROUND

Patients diagnosed with relapsed/refractory (R/R) diffuse large B cell and high grade B cell lymphomas (DLBCL/HGBL) may achieve prolonged survival following receipt of high dose chemotherapy/autologous stem cell transplantation (HDC/ASCT) or CD19-directed chimeric antigen receptor-modified T cells (CART19). While early results from randomized clinical trials suggest that assignment to CART19 versus salvage immunochemotherapy as second-line therapy results in improved survival, analysis of a large series of patients who actually received HDC/ASCT or CART19 has yet to be performed, and may inform future research efforts to optimize risk-stratification of R/R DLBCL/HGBL patients who are candidates for either therapy.

OBJECTIVE

To understand clinicopathologic factors which predict for freedom from treatment failure (FFTF) for R/R DLBCL/HGBL patients following receipt of HDC/ASCT or CART19, and compare patterns of TF for R/R DLBCL/HGBL patients receiving either HDC/ASCT or CART19.

STUDY DESIGN

Patients age ≤75 with R/R DLBCL/HGBL who received HDC/ASCT demonstrating partial or complete metabolic response to salvage immunochemotherapy and/or CART19 in the standard-of-care setting at the University of Pennsylvania from 2013-21 were included. Survival analyses were performed from the time of infusion of either HDC/ASCT or CART19 as well landmark time points post-infusion for patients who achieved FFTF.

RESULTS

For 100 HDC/ASCT patients with median length of follow-up of 62.7 months, the estimated rate of 36 month FFTF and overall survival were 59% and 81%, respectively. For 109 CART19 patients with median length of follow-up of 37.6 months, the estimated rate of 36 month FFTF and overall survival were 24% and 48%, respectively. HDC/ASCT patients achieved significantly higher rates of estimated 36 month FFTF if achieving actual FFTF at 3, 6, 12 and 24 months. Additionally, the incidence of baseline characteristics that predicted for TF at 36 months for either HDC/ASCT or CART19 patients was either similar or significantly lower at for CART19 as compared to HDC/ASCT patients who achieved actual FFTF at 3, 6, 12 and 24 months.

CONCLUSION

Patients with R/R DLBCL/HGBL achieving response to salvage immunochemotherapy who receive HDC/ASCT experience a high rate of estimated FFTF regardless of harboring features predictive of resistance to salvage immunochemotherapy, which may be more durable than that of R/R DLBCL/HGBL patients receiving CART19. These findings support further investigation of disease characteristics, such as molecular features, which may predict response to salvage immunochemotherapy in patients fit for HDC/ASCT.

DTRMWXHS-12, a novel Bruton tyrosine kinase inhibitor, in combination with everolimus and pomalidomide in patients with relapsed/refractory lymphomas: An open-label, multicenter, phase 1a/1b study

Preclinical studies have shown augmented activity when combining Bruton tyrosine kinase inhibitors (BTKi) with inhibitors of mammalian target of rapamycin (mTOR) and immunomodulatory agents (IMiD). We conducted a phase 1, open-label study at five centers in USA to evaluate the safety of triplet BTKi/mTOR/IMiD therapy. Eligible patients were adults aged 18 years or older with relapsed/refractory CLL, B cell NHL, or Hodgkin lymphoma. Our dose escalation study used an accelerated titration design and moved sequentially from single agent BTKi (DTRMWXHS-12), doublet (DTRMWXHS-12 + everolimus), and then to triplet therapy (DTRMWXHS-12 + everolimus + pomalidomide). All drugs were dosed once daily on days 1-21 of each 28-day cycle. The primary goal was to establish the recommended phase 2 dose of the triplet combination. Between September 27, 2016, and July 24, 2019, a total of 32 patients with a median age of 70 years (range 46 to 94 years) were enrolled. No MTD was identified for monotherapy and the doublet combination. The MTD for the triplet combination was determined to be DTRMWXHS-12 200 mg + everolimus 5 mg + pomalidomide 2 mg. Responses across all studied cohorts were seen in 13 of 32 (41.9%). Combining DTRMWXHS-12 with everolimus and pomalidomide is tolerable and shows clinical activity. Additional trials could confirm benefit of this all-oral combination therapy for relapsed/refractory lymphomas.

Treatment Discontinuation Patterns for Patients With Chronic Lymphocytic Leukemia in Real-World Settings: Results From a Multi-Center International Study

INTRODUCTION

This study assessed treatment discontinuation patterns and reasons among chronic lymphocytic leukemia (CLL) patients initiating first-line (1L) and second-line (2L) treatments in real-world settings.

MATERIALS AND METHODS

Using deidentified electronic medical records from the CLL Collaborative Study of Real-World Evidence, premature treatment discontinuation was assessed among FCR, BR, BTKi-based, and BCL-2-based regimen cohorts.

RESULTS

Of 1364 1L patients (initiated in 1997-2021), 190/13.9% received FCR (23.7% discontinued prematurely); 255/18.7% received BR (34.5% discontinued prematurely); 473/34.7% received BTKi-based regimens, of whom 28.1% discontinued prematurely; and 43/3.2% received venetoclax-based regimens, of whom 16.3% discontinued prematurely (venetoclax monotherapy: 7/0.5%, of whom 42.9% discontinued; VG/VR: 36/2.6%, of whom 11.1% discontinued). The most common reasons for treatment discontinuation were adverse events (FCR: 25/13.2%; BR: 36/14.1%; BTKi-based regimens: 75/15.9%) and disease progression (venetoclax-based: 3/7.0%). Of 626 2L patients, 20/3.2% received FCR (50.0% discontinued); 62/9.9% received BR (35.5% discontinued); 303/48.4% received BTKi-based regimens, of whom 38.0% discontinued; and 73/11.7% received venetoclax-based regimens, of whom 30.1% discontinued (venetoclax monotherapy: 27/4.3%, of whom 29.6% discontinued; VG/VR: 43/6.9%, of whom 27.9% discontinued). The most common reasons for treatment discontinuation were adverse events (FCR: 6/30.0%; BR: 11/17.7%; BTKi-based regimens: 60/19.8%; venetoclax-based: 6/8.2%).

CONCLUSION

The findings of this study highlight the continued need for tolerable therapies in CLL, with finite therapy offering a better tolerated option for patients who are newly diagnosed or relapsed/refractory to prior treatments.

Modulation of the gut microbiota engages antigen cross-presentation to enhance antitumor effects of CAR T cell immunotherapy

Several studies have shown the influence of commensal microbes on T cell function, specifically in the setting of checkpoint immunotherapy for cancer. In this study, we investigated how vancomycin-induced gut microbiota dysbiosis affects chimeric antigen receptor (CAR) T immunotherapy using multiple preclinical models as well as clinical correlates. In two murine tumor models, hematopoietic CD19+-A20 lymphoma and CD19+-B16 melanoma, mice receiving vancomycin in combination with CD19-directed CAR T cell (CART-19) therapy displayed increased tumor control and tumor-associated antigens (TAAs) cross-presentation compared with CART-19 alone. Fecal microbiota transplant from human healthy donors to pre-conditioned mice recapitulated the results obtained in naive gut microbiota mice. Last, B cell acute lymphoblastic leukemia patients treated with CART-19 and exposed to oral vancomycin showed higher CART-19 peak expansion compared with unexposed patients. These results substantiate the role of the gut microbiota on CAR T cell therapy and suggest that modulation of the gut microbiota using vancomycin may improve outcomes after CAR T cell therapy across tumor types.

Salvage radiotherapy for relapsed/refractory non-Hodgkin lymphoma following CD19 chimeric antigen receptor T-cell (CART) therapy

Background and purpose

CD19-targeting chimeric antigen receptor T-cell (CART) therapy is a promising treatment for relapsed/refractory non-Hodgkin lymphoma, but most patients experience post-CART progression. We describe our institutional experience of salvage radiotherapy (SRT) in this setting.

Materials and methods

Of 94 patients who received CART therapy from 2018 to 2020, 21 received SRT for post-CART progression. Patients were divided into two groups: locoregional disease (n = 9 [43 %], all disease encompassable within an RT field) and advanced disease (n = 12 [57 %]). Patterns of failure, progression-free survival (PFS), overall survival (OS), and toxicity were assessed.

Results

Median time from CART infusion to SRT was 4.0 months (range, 0.6-11.5 months). In the locoregional disease group, 8/9 patients (89 %) were treated with comprehensive SRT to a median dose of 37.5 Gy in a median of 15 fractions. In the advanced disease group, all patients (n = 12) were treated with focal SRT to a median dose of 20.8 Gy in a median of 5 fractions. Median follow-up post-SRT was 15.2 months. In-field response was observed in 8/9 (89 %) in the locoregional disease and 8/9 (89 %) evaluable patients in the advanced disease groups. 17/18 evaluable patients (94 %) patients experienced post-SRT progression, all with a distant component. Median OS was 7.4 months; 21 months for locoregional disease versus 2.4 months for advanced disease (p = 0.0002). Median PFS was 1.1 month, and similarly poor regardless of group. No grade ≥ 3 toxicities occurred.

Conclusions

SRT post-CART therapy appears safe with encouraging in-field response but high rates of out-of-field progression, even for those presenting with locoregional disease, highlighting the need for integration of novel systemic agents.

Assessment of Healthcare Resource Utilization and Hospitalization Costs in Patients With Relapsed or Refractory Follicular Lymphoma Undergoing CAR-T Cell Therapy With Tisagenlecleucel: Results From the ELARA Study

Follicular lymphoma (FL) is generally considered an indolent disease, although patients with relapsing FL experience progressively shorter durations of response to second or later lines of therapy. The ongoing ELARA trial in adult patients with relapsed/refractory (r/r) FL treated with tisagenlecleucel demonstrated an overall response rate of 86.2% and a complete response rate of 69.1%, with no treatment-related deaths. Tisagenlecleucel was administered in the outpatient setting in 18% of patients in ELARA; however, there is limited knowledge concerning the impact of inpatient versus outpatient tisagenlecleucel administration on healthcare resource utilization (HCRU) among patients with r/r FL. Here, we present the first HCRU analysis among patients with r/r FL who received tisagenlecleucel in the Phase II, single-arm, multicenter ELARA trial. HCRU was characterized using hospitalization data from day 1 to month 2 after tisagenlecleucel infusion. Information on length of stay, facility use, and discharge was assessed in patients who received tisagenlecleucel in the outpatient or inpatient setting. All costs were inflated to 2020 US dollars. As of August 3, 2021 (20-month median follow-up), 17/97 (18%) r/r FL patients were infused in an outpatient setting. Patients infused in the outpatient setting generally had favorable Eastern Cooperative Oncology Group performance status and Follicular Lymphoma International Prognostic Index scores, and less bulky disease at baseline. However, the outpatients had higher proportions of patients with grade 3A FL, primary refractory disease, and >5 lines of prior therapy compared with inpatients. Forty-one percent of patients treated in the outpatient setting did not require hospitalization within 30 days after infusion, and outpatients who did require hospitalization had a shorter average length of stay compared with inpatients (5 versus 13 days). No outpatients required intensive care unit (ICU) admission, whereas 9% of inpatients were admitted to the ICU. The mean postinfusion hospitalization costs were $7477 and $40,054 in the outpatient and inpatient settings, respectively. Efficacy between both groups was similar. Tisagenlecleucel can be safely administered to some patients in the outpatient setting, which may reduce HCRU for patients with r/r FL.

Pembrolizumab for patients with non-Hodgkin lymphoma: phase 1b KEYNOTE-013 study

The multicohort phase 1b KEYNOTE-013 study (NCT01953692) evaluated the safety and efficacy of pembrolizumab in patients with relapsed or refractory NHL who were ineligible for or failed hematopoietic cell transplantation (HCT). Patients received pembrolizumab (cohort 4) or pembrolizumab plus lenalidomide (cohort 5). Primary end points were safety and objective response rate (ORR) per IWG 2007 criteria. Cohort 4 included 89 patients. ORR was 22% (19/86; 90% CI 15-31; 10 CR, nine PR); ORRs by disease type were 48% (10/21), 10% (2/20), 12% (5/41), and 50% (2/4), for PMBCL, FL, DLBCL, and 'other' NHL, respectively. Toxicity was as predicted. Cohort 5 included 19 patients. ORR was 39% (90% CI 20-61; four CR, three PR). Hematologic toxicities were the most common treatment-related AEs. In conclusion, pembrolizumab following HCT ineligibility/failure confirms prior experience in PMBCL but not with NHL subtypes in this study. Additional analyses in DLBCL may not be warranted.

Efficacy and safety of tisagenlecleucel in adult Japanese patients with relapsed or refractory follicular lymphoma: results from the phase 2 ELARA trial

BACKGROUND

Tisagenlecleucel yielded a high durable response rate in patients with relapsed/refractory (r/r) follicular lymphoma (FL) in the global phase 2 ELARA trial. Here, we report the efficacy, safety, and cellular kinetics of tisagenlecleucel in a subgroup of Japanese patients with r/r FL from ELARA.

METHODS

ELARA (NCT03568461) is a global single-arm trial of tisagenlecleucel in patients with r/r FL who received ≥ 2 prior lines of therapy. The primary endpoint was the complete response rate (CRR), and the secondary endpoints were the overall response rate, duration of response, progression-free survival, overall survival, safety, and cellular kinetics.

RESULTS

As of March 29, 2021, nine Japanese patients were enrolled and received tisagenlecleucel with a median follow-up of 13.6 months (range, 10.5‒19.3). Per independent review committee, CRR was 100% (95% CI 63.1‒100). Within 8 weeks of infusion, cytokine release syndrome (CRS) of any grade was reported in 6 patients (66.7%); however, no grade ≥ 3 CRS or any grade serious neurological events or treatment-related deaths were observed.

CONCLUSION

Tisagenlecleucel showed high efficacy and manageable safety in adult Japanese patients with r/r FL. Moreover, the clinical outcomes were similar to the global population, which supports the potential of tisagenlecleucel in Japanese patients with r/r FL.

Anti-CD19 CAR T cells in combination with ibrutinib for the treatment of chronic lymphocytic leukemia

In chronic lymphocytic leukemia (CLL) patients who achieve a complete remission (CR) to anti-CD19 chimeric antigen receptor T cells (CART-19), remissions are remarkably durable. Preclinical data suggesting synergy between CART-19 and the Bruton's tyrosine kinase (BTK) inhibitor ibrutinib prompted us to conduct a prospective single-center phase 2 trial in which we added autologous anti-CD19 humanized binding domain T cells (huCART-19) to ibrutinib in patients with CLL not in CR despite ≥6 months of ibrutinib. The primary endpoints were safety, feasibility, and achievement of a CR within 3 months. Of 20 enrolled patients, 19 received huCART-19. The median follow-up for all infused patients was 41 months (range, 0.25-58 months). Eighteen patients developed cytokine release syndrome (CRS; grade 1-2 in 15 of 18 subjects), and 5 developed neurotoxicity (grade 1-2 in 4 patients, grade 4 in 1 patient). While the 3-month CR rate among International Working Group on CLL (iwCLL)-evaluable patients was 44% (90% confidence interval [CI], 23-67%), at 12 months, 72% of patients tested had no measurable residual disease (MRD). The estimated overall and progression-free survival at 48 months were 84% and 70%, respectively. Of 15 patients with undetectable MRD at 3 or 6 months, 13 remain in ongoing CR at the last follow-up. In patients with CLL not achieving a CR despite ≥6 months of ibrutinib, adding huCART-19 mediated a high rate of deep and durable remissions. ClinicalTrials.gov number, NCT02640209.

Patterns of Use, Outcomes, and Resource Utilization among Recipients of Commercial Axicabtagene Ciloleucel and Tisagenlecleucel for Relapsed/Refractory Aggressive B Cell Lymphomas

Axicabtagene ciloleucel (axi-cel) and tisagenlecleucel (tisa-cel) are CD19-directed chimeric antigen receptor (CAR) T cell therapies approved for the treatment of relapsed/refractory aggressive B cell lymphomas. We present a multicenter retrospective study among centers that prescribe either commercial product to evaluate usage patterns, safety and efficacy outcomes, and resource utilization. Data collection included all patients from 8 US centers who underwent apheresis between May 1, 2018, and July 31, 2019. Patient selection, toxicity management, and disease assessment followed institutional practices. Cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS) were graded according to American Society for Transplantation and Cellular Therapy consensus criteria, and tumor responses were assessed according to the Lugano 2014 classification scheme. A total of 260 patients underwent apheresis, including 168 (65%) for axi-cel and 92 (35%) for tisa-cel. Among the infused patients, the median age was 59 years for axi-cel recipients and 67 years for tisa-cel recipients (P < .001). The median time from apheresis to infusion was 28 days for axi-cel recipients and 45 days for tisa-cel recipients (P < .001). Sixty-one percent of the axi-cel recipients and 43% of the tisa-cel recipients would have been ineligible for the ZUMA-1 and JULIET trials, respectively. Grade ≥3 CRS occurred in 9% of axi-cel recipients and in 1% of tisa-cel recipients (P = .017), and grade ≥3 ICANS was seen in 38% of axi-cel recipients and 1% of tisa-cel recipients (P < .001). Inpatient cell therapy infusion was common (92% in axi-cel recipients, 37% in tisa-cel recipients). The day 90 overall response rate was 52% in the axi-cel group and 41% in the tisa-cel group (P = .113), with complete response in 44% and 35%, respectively (P = .319). Twelve-month progression-free survival (42% versus 32%; P = .206) and overall survival (62% versus 59%; P = .909) rates were comparable in the axi-cel and tisa-cel groups. Baseline characteristics differed between the 2 groups, although response rates and survival outcomes were comparable, albeit lower than those in the pivotal trials. Safety and resource utilization appear to be key differentiators between axi-cel and tisa-cel.

Bendamustine is safe and effective for lymphodepletion before tisagenlecleucel in patients with refractory or relapsed large B-cell lymphomas

BACKGROUND

Anti-CD19 chimeric antigen receptor T-cell immunotherapy (CAR-T) is now a standard treatment of relapsed or refractory B-cell non-Hodgkin lymphomas; however, a significant portion of patients do not respond to CAR-T and/or experience toxicities. Lymphodepleting chemotherapy is a critical component of CAR-T that enhances CAR-T-cell engraftment, expansion, cytotoxicity, and persistence. We hypothesized that the lymphodepletion regimen might affect the safety and efficacy of CAR-T.

PATIENTS AND METHODS

We compared the safety and efficacy of lymphodepletion using either fludarabine/cyclophosphamide (n = 42) or bendamustine (n = 90) before tisagenlecleucel in two cohorts of patients with relapsed or refractory large B-cell lymphomas treated consecutively at three academic institutions in the United States (University of Pennsylvania, n = 90; Oregon Health & Science University, n = 35) and Europe (University of Vienna, n = 7). Response was assessed using the Lugano 2014 criteria and toxicities were assessed by the Common Terminology Criteria for Adverse Events (CTCAE) version 5.0 and, when possible, the American Society for Transplantation and Cellular Therapy (ASTCT) consensus grading.

RESULTS

Fludarabine/cyclophosphamide led to more profound lymphocytopenia after tisagenlecleucel infusion compared with bendamustine, although the efficacy of tisagenlecleucel was similar between the two groups. We observed significant differences, however, in the frequency and severity of adverse events. In particular, patients treated with bendamustine had lower rates of cytokine release syndrome and neurotoxicity. In addition, higher rates of hematological toxicities were observed in patients receiving fludarabine/cyclophosphamide. Bendamustine-treated patients had higher nadir neutrophil counts, hemoglobin levels, and platelet counts, as well as a shorter time to blood count recovery, and received fewer platelet and red cell transfusions. Fewer episodes of infection, neutropenic fever, and post-infusion hospitalization were observed in the bendamustine cohort compared with patients receiving fludarabine/cyclophosphamide.

CONCLUSIONS

Bendamustine for lymphodepletion before tisagenlecleucel has efficacy similar to fludarabine/cyclophosphamide with reduced toxicities, including cytokine release syndrome, neurotoxicity, infectious and hematological toxicities, as well as reduced hospital utilization.

Outcomes of Tisagenlecleucel in Lymphoma Patients With Predominant Management in an Ambulatory Setting

INTRODUCTION

Chimeric antigen receptor T-cell therapy (CAR T) is a revolutionary adoptive immunotherapy approach in lymphoma; however, substantial resources are necessary for administration and care of these patients. Our institution has administered tisagenlecleucel primarily in an outpatient setting, and here we report our clinical outcomes.

PATIENTS AND METHODS

We conducted a single institution, retrospective study investigating outcomes of adult lymphoma patients treated with commercial tisagenlecleucel between 10/2017 and 12/2020. We analyzed patient characteristics and outcomes of efficacy and safety including overall response rate, progression-free survival, overall survival and cytokine-release syndrome, neurotoxicity, and hospitalizations.

RESULTS

Seventy-two patients with relapsed or refractory non-Hodgkin lymphoma (NHL) who received commercial tisagenlecleucel were identified; 68 (94.4%) patients received outpatient tisagenlecleucel. The overall response rate was 43% with a complete response observed in 25 patients (34.7%). At a median follow-up of 9.1 months, the median progression-free survival was 3.3 months. Grade 3-4 cytokine release syndrome was not observed in the study group and two patients had grade 3-4 neurotoxicity. Twenty-six patients (36.1%) were admitted within 30 days after infusion with a median length of stay of 5 days. Fourteen patients (19.4%) were admitted within 72 hours of infusion. No patient died of CAR T cell-related toxicity.

CONCLUSION

Our experience affirms treatment with tisagenlecleucel in the outpatient setting is safe and feasible with close supervision and adequate institutional experience. After infusion, adverse events were manageable and the majority of patients did not require hospitalization.

Modulation of BCL-2 in both T Cells and Tumor Cells to Enhance Chimeric Antigen Receptor T cell Immunotherapy against Cancer

Chimeric Antigen Receptor T-cell (CART) immunotherapy led to unprecedented responses in patients with refractory/relapsed B-cell non-Hodgkin lymphoma (NHL); nevertheless, two-thirds of patients fail this treatment. Resistance to apoptosis is a key feature of cancer cells that associates with treatment failure. In 87 NHL patients treated with anti-CD19 CART, we found that chromosomal alteration of BCL-2, a critical anti-apoptotic regulator, in lymphoma cells was associated with reduced survival. Therefore, we combined CART19 with the FDA-approved BCL-2-inhibitor, venetoclax, and demonstrated in vivo synergy in venetoclax-sensitive NHL. However, higher venetoclax doses for venetoclax-resistant lymphomas resulted in CART toxicity. To overcome this limitation, we developed venetoclax-resistant CART by overexpressing mutated BCL-2(F104L) which is not recognized by venetoclax. Notably, BCL-2(F104L)-CART19 synergized with venetoclax in multiple lymphoma xenograft models. Furthermore, we uncovered that BCL-2 overexpression in T cells per se enhanced CART anti-tumor activity in preclinical models and in patients by prolonging CART persistence.

Abstract 3602: Mechanisms of CAR T cell dysfunction and identification of transcription factors that drive the exhaustion phenotype

Chimeric antigen receptor (CAR) T cell immunotherapy is FDA approved for the treatment of a subset of B cell malignancies but has shown limited clinical success in solid tumor therapy. T cell exhaustion is an important factor involved in treatment failure, and can, in part, result from continuous stimulation of the CAR by tumor cells expressing the cognate antigen. To gain deeper understanding of CAR T cell exhaustion induced by chronic antigen exposure (CAE), we developed and validated a robust in vitro model, in which mesothelin-redirected CAR T cells (M5CAR) were continuously stimulated with mesothelin-expressing AsPC-1 pancreatic tumor cells such that tumor cells were never cleared, and we characterized these CAE CAR T cells by gene expression at population and single-cell levels, and by epigenetic analyses.

CAE M5CAR T cells recapitulate the hallmarks of T cell exhaustion, including reduced proliferation, down-modulation of surface CAR, decreased cytokine production, and reduced cytotoxicity. In addition, CAR T cells undergoing CAE have a transcriptional signature and an epigenetic landscape consistent with exhaustion. Further, transcriptomic analysis revealed that CAE M5CAR T cells undergo a transition from T cells to a post-thymic NK-like T cell phenotype. This plasticity was confirmed by TCR lineage tracing and was also detected in CD19 CAR T cells analyzed from post-infusion blood from DLBCL patients and in M5CAR T cells infiltrating relapsed tumors derived from a xenograft NSG/AsPC-1 mouse model. The dysfunctional signature and the NK phenotype were further detected in vivo by transcriptomic analysis in Ly95 TCR-specific TILs infiltrating NY-ESO-1 tumors. Among the genes included in the dysfunctional signature, the transcription factors SOX4 and ID3 were identified as potential regulators of dysfunction by differential gene expression and pathway analyses. To determine their role in the establishment of a dysfunctional phenotype, we generated ID3KO.M5 and SOX4KO.M5 CAR T cells using CRISPR technology in primary human lymphocytes. The cytotoxic potential of the M5 CAR T cell product generated was not modified by the genetic disruption of the transcription factors. However, when CAR T cells were challenged with chronic antigen stimulation, KO CAR T cells showed a significant reduction of the dysfunctional signature and the NK-like T cell gene expression. Importantly, CAE KO CAR T cells exhibit improved cytotoxicity as compared to Mock.M5CAR T cells.

In summary, we have developed a robust in vitro model that recapitulates the hallmarks of T cell exhaustion and that facilitated the identification of a gene signature defining CAR dysregulation, a T-to-NK-like-T cell transition as a novel feature of CAR T cell dysfunction and the transcription factors SOX4 and ID3 as key regulators of CAR T cell exhaustion.

Citation Format: M. Angela Aznar, Charly R. Good, Shunichiro Kuramitsu, Parisa Samareh, Sangya Agarwal, Greg Donahue, Kenichi Ishiyama, Nils Wellhausen, Austin K. Rennels, Yujie Ma, Lifeng Tian, Sonia Guedan, Katherine A. Alexander, Zhen Zhang, Philipp C. Rommel, Nathan Singh, Karl M. Glastad, Max W. Richardson, Keisuke Watanabe, Janos L. Tanyi, Mark H. O’Hara, Marco Ruella, Simon F. Lacey, Edmund K. Moon, Stephen J. Schuster, Steven M. Albelda, Lewis L. Lanier, Regina M. Young, Shelley L. Berger, Carl H. June. Mechanisms of CAR T cell dysfunction and identification of transcription factors that drive the exhaustion phenotype [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3602.

Clinical laboratory mutation analysis performed on aggressive B cell non-Hodgkin lymphoma patient biopsies

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Background: Results from comprehensive genomic analysis performed on aggressive B cell non-Hodgkin lymphomas (aBNHL) patient (pt) biopsies (bx) have identified mutations (mut) which may be predictive of pt survival. However, results from mut analysis (MA) performed on aBNHL pt bx in clinical laboratories are not well-described. Methods: Bx diagnostic of non-Burkitt aBNHL obtained from 7/2015-2/2021 with MA performed in the Penn Center for Personalized Diagnostics clinical laboratory using 3 consecutive versions of lymphoma sequencing panels were retrospectively analyzed. Mut tested varied by panel. Mut detected with variant allele frequency (VAF) ≥10% were included. Results: MA was performed on 293 aBNHL pt bx with a successful assay for 270 (7.8% failure rate). Request for MA was made by interpreting hematopathologist 93% and treating clinician 7%. Median turnaround time (TAT) from receipt of bx to result report was 18 (range 8-53) days. Notable pt characteristics included prior/concurrent indolent lymphoma (IL) 31% and prior systemic therapy received for IL and/or aBNHL 38%. Notable bx characteristics included bx type paraffin-embedded tissue 85% and bone marrow 12%, histologic classification diffuse large B cell lymphoma 86% and high grade B cell lymphoma 13%, cell of origin (COO) by Hans algorithm non-germinal center B (non-GCB) 51% and GCB 44%, known double expressor lymphoma 30%, known MYC rearrangement 18%, known double hit lymphoma 9% and any mut detected with VAF ≥10% 82%. Number and percentage of mut occurring in ≥10% of bx (minimum tested bx for mut ≥92) with associated COO are listed in the table. Subset analysis of 147 bx obtained from pts with newly-diagnosed aBNHL (15% with previously-untreated IL) had similar bx characteristics to the entire population were analyzed for the presence of mut reported in poor-prognosis COO-associated classifications: Cluster 5 for non-GCB and Cluster 3 for GCB (PMID: 29713087), double-hit signature (DHITsig) for GCB (PMID: 30523716) and molecular high grade (MHG) for GCB (PMID: 30523719). For 77 non-GCB bx, 19% had Cluster 5 mut. For 59 GCB bx, 56% had at least one of Cluster 3, DHITsig or MHG mut. Conclusions: Clinical laboratory MA performed on nearly 300 aBNHL pt bx was highly successful with a short TAT and demonstrated recurrent gene mut associated with aBNHL development. In the subset of bx from previously-untreated pts, MA identified mut associated with poor-prognosis genetic subtypes of aBNHL.[Table: see text]

Characterization of CD20 expression loss as a mechanism of resistance to mosunetuzumab in patients with relapsed/refractory B-cell non-Hodgkin lymphomas

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Background: Mosunetuzumab (M) is a bispecific antibody targeting CD20 and CD3 that redirects T cells to engage and eliminate malignant B cells being developed for relapsed or refractory (R/R) B-cell non-Hodgkin lymphomas (B-NHL). CD20 is an optimal target, with uniform expression across B-NHL histologies and minimal receptor turnover. We characterized CD20 loss as a potential mechanism of resistance to M in patients (pts) on a Phase I/II trial (NCT02500407) receiving M monotherapy for the treatment (tx) of R/R B-NHL. Methods: Pts with R/R B-NHL received M intravenously in 3-week cycles, for eight to 17 cycles depending on tumor response. At baseline (BL), biomarker-evaluable (archival or fresh) biopsies were collected from 293 pts. Biopsies from 62 pts were collected at additional time points during tx with M and/or at disease progression (PD). The proportion of CD20+ and PAX5+ tumor cells was determined by immunohistochemistry (IHC) using dual-staining with anti-CD20 (clone L26, VENTANA) and anti-PAX5 (clone DAK-PAX5, DAKO) antibodies. Expression of MS4A1, the gene encoding CD20 , was measured by RNA-sequencing (RNA-seq); MS4A1 mutation profiling was performed by whole exome sequencing (WES). Levels of CD20 expression were assessed relative to response rates. Correlative analyses were performed and assessed centrally (IHC, RNA-seq, and WES) and locally (IHC). Results: CD20 levels were consistently high ( > 75% CD20+PAX5+ cells) in the majority of BL biopsies and generally comparable across histologies (FL, DLBCL, tFL, MCL, and RT). BL CD20 loss (≤5% CD20+PAX5+ cells) was seen in 16/293 pts (5.5%), more commonly in aggressive NHL, and responses to M were not seen in these pts. Among 62 pts with BL and on-tx/at-PD biopsies, BL CD20 levels were ≤5% in 7/62 pts (11%) (6/7 pts [86%] progressed before completing Cycle 2). CD20 levels were maintained in on-tx biopsies from 23/24 pts (96%). At PD, biopsies showed CD20 loss in 7/26 pts (27%). For five pts with BL, on-tx and at-PD biopsies, all pts maintained CD20 while on-tx and 1/5 pts (20%) had CD20 loss at PD. There was no clear association between CD20 reduction and histology. Data from 185 BL biopsies showed generally concordant levels of CD20 gene and protein expression (r = 0.72). In 10/185 pts (5%), MS4A1 was expressed without detectable CD20 protein expression; DNA sequencing revealed novel mutations in MS4A1, including mutations leading to truncation of the protein. CD20 transmembrane and extra-cellular domain mutations were also observed but do not block CD20 expression. Conclusions: In pts with R/R B-NHL treated with M, low BL CD20 expression is associated with lack of response to M. During M tx, loss of tumor cell expression of CD20 is one mechanism of acquired resistance; however, CD20 expression is maintained in most pts with PD, implying alternative mechanisms for acquired M resistance. Clinical trial information: NCT02500407.

Gut microbiome correlates of response and toxicity following anti-CD19 CAR T cell therapy

Anti-CD19 chimeric antigen receptor (CAR) T cell therapy has led to unprecedented responses in patients with high-risk hematologic malignancies. However, up to 60% of patients still experience disease relapse and up to 80% of patients experience CAR-mediated toxicities, such as cytokine release syndrome or immune effector cell-associated neurotoxicity syndrome. We investigated the role of the intestinal microbiome on these outcomes in a multicenter study of patients with B cell lymphoma and leukemia. We found in a retrospective cohort (n = 228) that exposure to antibiotics, in particular piperacillin/tazobactam, meropenem and imipenem/cilastatin (P-I-M), in the 4 weeks before therapy was associated with worse survival and increased neurotoxicity. In stool samples from a prospective cohort of CAR T cell recipients (n = 48), the fecal microbiome was altered at baseline compared to healthy controls. Stool sample profiling by 16S ribosomal RNA and metagenomic shotgun sequencing revealed that clinical outcomes were associated with differences in specific bacterial taxa and metabolic pathways. Through both untargeted and hypothesis-driven analysis of 16S sequencing data, we identified species within the class Clostridia that were associated with day 100 complete response. We concluded that changes in the intestinal microbiome are associated with clinical outcomes after anti-CD19 CAR T cell therapy in patients with B cell malignancies.

Second-Line Tisagenlecleucel or Standard Care in Aggressive B-Cell Lymphoma

BACKGROUND

Patient outcomes are poor for aggressive B-cell non-Hodgkin's lymphomas not responding to or progressing within 12 months after first-line therapy. Tisagenlecleucel is an anti-CD19 chimeric antigen receptor T-cell therapy approved for diffuse large B-cell lymphoma after at least two treatment lines.

METHODS

We conducted an international phase 3 trial involving patients with aggressive lymphoma that was refractory to or progressing within 12 months after first-line therapy. Patients were randomly assigned to receive tisagenlecleucel with optional bridging therapy (tisagenlecleucel group) or salvage chemotherapy and autologous hematopoietic stem-cell transplantation (HSCT) (standard-care group). The primary end point was event-free survival, defined as the time from randomization to stable or progressive disease at or after the week 12 assessment or death. Crossover to receive tisagenlecleucel was allowed if a defined event occurred at or after the week 12 assessment. Other end points included response and safety.

RESULTS

A total of 322 patients underwent randomization. At baseline, the percentage of patients with high-grade lymphomas was higher in the tisagenlecleucel group than in the standard-care group (24.1% vs. 16.9%), as was the percentage with an International Prognostic Index score (range, 0 to 5, with higher scores indicating a worse prognosis) of 2 or higher (65.4% vs. 57.5%). A total of 95.7% of the patients in the tisagenlecleucel group received tisagenlecleucel; 32.5% of the patients in the standard-care group received autologous HSCT. The median time from leukapheresis to tisagenlecleucel infusion was 52 days. A total of 25.9% of the patients in the tisagenlecleucel group had lymphoma progression at week 6, as compared with 13.8% of those in the standard-care group. The median event-free survival in both groups was 3.0 months (hazard ratio for event or death in the tisagenlecleucel group, 1.07; 95% confidence interval, 0.82 to 1.40; P = 0.61). A response occurred in 46.3% of the patients in the tisagenlecleucel group and in 42.5% in the standard-care group. Ten patients in the tisagenlecleucel group and 13 in the standard-care group died from adverse events.

CONCLUSIONS

Tisagenlecleucel was not superior to standard salvage therapy in this trial. Additional studies are needed to assess which patients may obtain the most benefit from each approach. (Funded by Novartis; BELINDA ClinicalTrials.gov number, NCT03570892.).

Pembrolizumab for B-cell lymphomas relapsing after or refractory to CD19-directed CAR T-cell therapy

CD19-directed chimeric antigen receptor-modified (CAR T) T cells achieve durable remissions in about 30% to 40% of relapsed/refractory large B-cell lymphomas. T-cell exhaustion and/or an immunosuppressive tumor microenvironment may contribute to CAR T-cell failure. Pembrolizumab, an anti-PD1 immune checkpoint inhibitor, may reverse T-cell exhaustion after CAR T-cell therapy. We treated 12 patients with B-cell lymphomas who were either refractory to (n = 9) or relapsed after (n = 3) CD19-directed CAR T-cell (4-1BB-costimulated) therapy with pembrolizumab 200 mg IV every 3 weeks. Median time from CAR T-cell infusion to first pembrolizumab dose was 3.3 months (range, 0.4-42.8 months). Pembrolizumab was well tolerated, and the only grade ≥3 adverse events related to pembrolizumab were neutropenia (n = 3; 25%). Best overall response rate after pembrolizumab was 25% (3 of 12 patients; 1 complete response; 2 partial responses). One (8%) patient had stable disease; thus, 4 of 12 (33%) patients had clinical benefit. After pembrolizumab, 4 patients with clinical benefit had an increase in percentage of CAR T cells by mass cytometry by time of flight (CyTOF); 3 of 4 of these patients also had increases in CAR19 transgene levels by quantitative polymerase chain reaction. Deep immune profiling using CyTOF revealed increased CAR T-cell activation and proliferation and less T-cell exhaustion in clinical responders. Together, PD1 blockade with pembrolizumab after CD19-directed CAR T-cell therapy appears safe and may achieve clinical responses in some patients with B-cell lymphomas refractory to or relapsed after CAR T-cell therapy. This trial was registered at www.clinicaltrials.gove as #NCT02650999.

Recognizing Unmet Need in the Era of Targeted Therapy for CLL/SLL: "What's Past Is Prologue" (Shakespeare)

The management of chronic lymphocytic leukemia (CLL) has undergone unprecedented changes over the last decade. Modern targeted therapies are incorporated into clinical practice. Unfortunately, patients have begun to develop resistance or intolerance to multiple classes. Symptomatic patients previously treated with a BTK inhibitor (BTKi) and venetoclax represent a new and rapidly growing unmet need in CLL. Here, we define unmet needs in a modern treatment context. We also critically review the literature for PI3K inhibitors and chemoimmunotherapy and lack of data to support their utility following BTKis and venetoclax. Finally, we suggest opportunities to ensure the continued innovation for patients with CLL.

Single-Agent Mosunetuzumab Shows Durable Complete Responses in Patients With Relapsed or Refractory B-Cell Lymphomas: Phase I Dose-Escalation Study

PURPOSE

Mosunetuzumab is a bispecific antibody targeting CD20 and CD3 that redirects T cells to engage and eliminate malignant B cells and is being developed for relapsed or refractory (R/R) B-cell non-Hodgkin lymphomas (B-NHLs).

METHODS

This first-in-human trial (ClinicalTrials.gov identifier: NCT02500407) evaluated the safety and tolerability and efficacy of mosunetuzumab in patients with R/R B-NHL and established the recommended phase II dose. Data from dose escalation are presented. Single-agent mosunetuzumab was administered intravenously in 3-week cycles, at full dose in cycle 1 day 1 (group A) or with ascending (step-up) doses during cycle 1 on days 1, 8, and 15 (group B), for eight or 17 cycles on the basis of tumor response.

RESULTS

Two hundred thirty patients were enrolled. Doses up to 2.8 mg and 60 mg were assessed in groups A and B, respectively; maximum tolerated dose was not exceeded. In group B (n = 197), common adverse events (≥ 20% of patients) were neutropenia (28.4%), cytokine release syndrome (27.4%), hypophosphatemia (23.4%), fatigue (22.8%), and diarrhea (21.8%). Cytokine release syndrome was mostly low-grade (grade ≥ 3: 1.0%) and mainly confined to cycle 1. Across the doses investigated (group B), best overall response rates were 34.9% and 66.2% in patients with aggressive and indolent B-NHL, respectively, and complete response rates were 19.4% and 48.5%. Among patients with a complete response, the median duration of response was 22.8 months (95% CI, 7.6 to not estimable) and 20.4 (95% CI, 16 to not estimable) in patients with aggressive and indolent B-NHL, respectively.

CONCLUSION

Mosunetuzumab, administered with step-up dosing, has a manageable safety profile and induces durable complete responses in R/R B-NHL. The expansion stage of the study is ongoing at the dose level of 1/2/60/60/30 mg selected for further study.

Tisagenlecleucel in adult relapsed or refractory follicular lymphoma: the phase 2 ELARA trial

Tisagenlecleucel is an autologous anti-CD19 chimeric antigen receptor-T cell therapy with clinically meaningful outcomes demonstrated in patients with relapsed/refractory (r/r) B-cell lymphoma. In a previous pilot study of tisagenlecleucel in r/r follicular lymphoma (FL), 71% of patients achieved a complete response (CR). Here we report the primary, prespecified interim analysis of the ELARA phase 2 multinational trial of tisagenlecleucel in adults with r/r FL after two or more treatment lines or who relapsed after autologous stem cell transplant (no. NCT03568461). The primary endpoint was CR rate (CRR). Secondary endpoints included overall response rate (ORR), duration of response, progression-free survival, overall survival, pharmacokinetics and safety. As of 29 March 2021, 97/98 enrolled patients received tisagenlecleucel (median follow-up, 16.59 months; interquartile range, 13.8-20.21). The primary endpoint was met. In the efficacy set (n = 94), CRR was 69.1% (95% confidence interval, 58.8-78.3) and ORR 86.2% (95% confidence interval, 77.5-92.4). Within 8 weeks of infusion, rates of cytokine release syndrome were 48.5% (grade ≥3, 0%), neurological events 37.1% (grade ≥3, 3%) and immune effector cell-associated neurotoxicity syndrome (ICANS) 4.1% (grade ≥3, 1%) in the safety set (n = 97), with no treatment-related deaths. Tisagenlecleucel is safe and effective in extensively pretreated r/r FL, including in high-risk patients.

Comparative efficacy of tisagenlecleucel and lisocabtagene maraleucel among adults with relapsed/refractory large B-cell lymphomas: an indirect treatment comparison

This study compared overall survival (OS), progression-free survival (PFS), complete response rate (CRR), and overall response rate (ORR) of tisagenlecleucel (tisa-cel) and lisocabtagene maraleucel (liso-cel) in relapsed or refractory large B-cell lymphomas (r/r LBCL). Using matching-adjusted indirect comparison (MAIC), individual patient-level data from JULIET (tisa-cel) were weighted to match the patient population in TRANSCEND (liso-cel). The main analysis compared infused JULIET patients (N = 106) with the TRANSCEND efficacy-evaluable set (EES) (N = 256 [infused]). After adjustment, OS, PFS, and the CRR were comparable between tisa-cel and liso-cel EES patients. The estimated adjusted 2-year OS, 2-year PFS, ORR, and CRR were 45.6, 38.2, 62.9, and 47.7%, respectively, for tisa-cel vs. 43.8, 42.1, 72.7, and 53.1% for liso-cel. A scenario analysis compared JULIET patients to the TRANSCEND primary analysis set (PAS) (N = 133). ORR was significantly higher in the TRANSCEND PAS compared with matched JULIET patients, but no significant differences in CRR were observed.