Baseline Serum Inflammatory Proteins Predict Poor CAR T Outcomes in Diffuse Large B-cell Lymphoma.

A subset of patients with diffuse large B-cell lymphoma (DLBCL) treated with CD19 chimeric antigen receptor (CAR) T-cell therapy have poor clinical outcomes. We report serum proteins associated with severe immune-mediated toxicities and inferior clinical responses in 146 patients with DLBCL treated with axicabtagene ciloleucel. We develop a simple stratification based on pre-lymphodepletion C reactive protein (CRP) and ferritin to classify patients into low-, intermediate-, and high-risk groups. We observe that patients in the high-risk category were more likely to develop grade ≥3 toxicities and had inferior overall and progression-free survival. We sought to validate our findings with two independent international cohorts demonstrating that patients classified as low-risk have excellent efficacy and safety outcomes. Based on routine and readily available laboratory tests that can be obtained prior to lymphodepleting chemotherapy, this simple risk stratification can inform patient selection for CAR T-cell therapy. SIGNIFICANCE: CAR T-cell therapy has changed the treatment paradigm for patients with relapsed/refractory hematologic malignancies. Despite encouraging efficacy, a subset of patients have poor clinical outcomes. We show that a simple clinically applicable model using pre-lymphodepletion CRP and ferritin can identify patients at high risk of poor outcomes. This article is featured in Selected Articles from This Issue, p. 80.

Bispecific CD33/CD123 targeted chimeric antigen receptor T cells for the treatment of acute myeloid leukemia.

CD33 and CD123 are expressed on the surface of human acute myeloid leukemia blasts and other noncancerous tissues such as hematopoietic stem cells. On-target off-tumor toxicities may limit chimeric antigen receptor T cell therapies that target both CD33 and CD123. To overcome this limitation, we developed bispecific human CD33/CD123 chimeric antigen receptor (CAR) T cells with an "AND" logic gate. We produced novel CD33 and CD123 scFvs from monoclonal antibodies that bound CD33 and CD123 and activated T cells. Screening of CD33 and CD123 CAR T cells for cytotoxicity, cytokine production, and proliferation was performed, and we selected scFvs for CD33/CD123 bispecific CARs. The bispecific CARs split 4-1BB co-stimulation on one scFv and CD3ζ on the other. In vitro testing of cytokine secretion and cytotoxicity resulted in selecting bispecific CAR 1 construct for in vivo analysis. The CD33/CD123 bispecific CAR T cells were able to control acute myeloid leukemia (AML) in a xenograft AML mouse model similar to monospecific CD33 and CD123 CAR T cells while showing no on-target off-tumor effects. Based on our findings, human CD33/CD123 bispecific CAR T cells are a promising cell-based approach to prevent AML and support clinical investigation.

Severe hematotoxicity after CD19 CAR-T therapy is associated with suppressive immune dysregulation and limited CAR-T expansion.

Prolonged cytopenias after chimeric antigen receptor (CAR) T cell therapy are a significant clinical problem and the underlying pathophysiology remains poorly understood. Here, we investigated how (CAR) T cell expansion dynamics and serum proteomics affect neutrophil recovery phenotypes after CD19-directed CAR T cell therapy. Survival favored patients with "intermittent" neutrophil recovery (e.g., recurrent neutrophil dips) compared to either "quick" or "aplastic" recovery. While intermittent patients displayed increased CAR T cell expansion, aplastic patients exhibited an unfavorable relationship between expansion and tumor burden. Proteomics of patient serum collected at baseline and in the first month after CAR-T therapy revealed higher markers of endothelial dysfunction, inflammatory cytokines, macrophage activation, and T cell suppression in the aplastic phenotype group. Prolonged neutrophil aplasia thus occurs in patients with systemic immune dysregulation at baseline with subsequently impaired CAR-T expansion and myeloid-related inflammatory changes. The association between neutrophil recovery and survival outcomes highlights critical interactions between host hematopoiesis and the immune state stimulated by CAR-T infusion.

Cardiac and inflammatory biomarker differences in adverse cardiac events after chimeric antigen receptor T-Cell therapy: an exploratory study.

BACKGROUND: Chimeric antigen receptor T- Cell (CAR-T) immunotherapy has been a breakthrough treatment for various hematological malignancies. However, cardiotoxicities such as new-onset heart failure, arrhythmia, acute coronary syndrome and cardiovascular death occur in 10-15% of patients treated with CAR-T. This study aims to investigate the changes in cardiac and inflammatory biomarkers in CAR-T therapy to determine the role of pro-inflammatory cytokines. METHODS: In this observational study, ninety consecutive patients treated with CAR-T underwent baseline cardiac investigation with electrocardiogram (ECG), transthoracic echocardiogram (TTE), troponin-I, and B-type natriuretic peptide (BNP). Follow-up ECG, troponin-I and BNP were obtained five days post- CAR-T. In a subset of patients (N = 53), serum inflammatory cytokines interleukin (IL)-2, IL-6, IL-15, interferon (IFN)-γ, tumor necrosis factor (TNF)-α, granulocyte-macrophage colony-stimulating factor (GM-CSF), and angiopoietin 1 & 2 were tested serially, including baseline and daily during hospitalization. Adverse cardiac events were defined as new-onset cardiomyopathy/heart failure, acute coronary syndrome, arrhythmia and cardiovascular death. RESULTS: Eleven patients (12%) had adverse cardiac events (one with new-onset cardiomyopathy and ten with new-onset atrial fibrillation). Adverse cardiac events appear to have occurred among patients with advanced age (77 vs. 66 years; p = 0.002), higher baseline creatinine (0.9 vs. 0.7 mg/dL; 0.007) and higher left atrial volume index (23.9 vs. 16.9mL/m2; p = 0.042). Day 5 BNP levels (125 vs. 63pg/mL; p = 0.019), but not troponin-I, were higher in patients with adverse cardiac events, compared to those without. The maximum levels of IL-6 (3855.0 vs. 254.0 pg/mL; p = 0.021), IFN-γ (474.0 vs. 48.8pg/mL; p = 0.006) and IL-15 (70.2 vs. 39.2pg/mL; p = 0.026) were also higher in the adverse cardiac events group. However, cardiac and inflammatory biomarker levels were not associated with cardiac events. Patients who developed cardiac events did not exhibit worse survival compared to patients without cardiac events (Log-rank p = 0.200). CONCLUSION: Adverse cardiac events, predominantly atrial fibrillation, occur commonly after CAR-T (12%). The changes in serial inflammatory cytokine after CAR-T in the setting of adverse cardiac events suggests pro-inflammation as a pathophysiology and require further investigation for their role in adverse cardiac events. TWEET BRIEF HANDLE: CAR-T related Cardiotoxicity has elevated cardiac and inflammatory biomarkers. #CARTCell #CardioOnc #CardioImmunology.

Outcomes of CD19-Directed Chimeric Antigen Receptor T Cell Therapy for Transformed Nonfollicular Lymphoma.

CD19-directed chimeric antigen receptor (CAR) T cell (CAR-T) therapy with axicabtagene ciloleucel (axi-cel) or tisagenlecleucel (tisa-cel) are approved for the treatment of relapsed or refractory large B cell lymphoma (LBCL), including de novo diffuse LBCL (DLBCL), primary mediastinal B cell lymphoma (PMBCL), and transformed follicular lymphoma (tFL). Transformed nonfollicular lymphomas (tNFLs), including transformed marginal zone lymphoma (tMZL) and transformed chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) were not included in their respective pivotal studies. This study was conducted to evaluate the outcomes of axi-cel and tisa-cel in tNFL patients, including those who received ibrutinib concomitantly through apheresis, lymphodepletion, and CAR-T infusion. This single-center retrospective study included all patients with tCLL/SLL, tMZL, tFL, and DLBCL/PMBCL treated with CAR-T therapy outside of a clinical trial setting from November 2017 to May 2021 at Moffitt Cancer Center, Tampa, Florida. We analyzed and compared outcomes in patients with tCLL/SLL or tMZL and patients with DLBCL/tFL. The study included 134 patients who received a total of 136 CAR-T treatments (111 with axi-cel and 25 with tisa-cel). Ninety patients had de novo DLBCL/PMBCL, 23 had tFL, and 21 had tNFL (12 with tMZL and 9 with tCLL/SLL). The overall response and complete response rates were 66.7% and 55.6%, respectively, for tCLL/SLL and 92.9% and 71.4% for tMZL. The overall response and complete response rates were not different between tNFL and DLBCL/tFL (P = .92 and .81, respectively). At a median follow-up of 21.3 months, the median progression-free survival (PFS) for tCLL/SLL was 5.4 months (95% confidence interval [CI], .8 month to not assessable [NA]); for tMZL, the median PFS was not reached (NR) (95% CI, 2.3 months to NA); and for DLBCL/tFL, the median PFS was 14.3 months (95% CI, 5.6 months to NA) (P = .58). The estimated 1-year PFS rate was 29.6% (95% CI, 5.2% to 60.7%) for tCLL/SLL, 50.0% (95% CI, 22.9% to 72.2%) for tMZL, 42.7% (95% CI, 22.4% to 61.6%) for tNFL, and 53.0% (95% CI, 42.3% to 62.5%) for DLBCL/tFL. The median overall survival was NR (95% CI, 9.2 months to NA) for tCLL/SLL, 27.1 months (95% CI, 8.5 months to NA) for tMZL, and NR (95% CI, 17.4 months to NA) for DLBCL/tFL (P = .79). Compared to the DLBCL/tFL cohort, tNFL patients were more likely to develop immune effector cell-associated neurologic syndrome (ICANS) and to receive tocilizumab (P = .04 and .01, respectively, after controlling for CAR-T product) and with a possibly higher incidence of grade ≥3 cytokine release syndrome (CRS) (P = .07). Two patients in the tNFL cohort died of treatment-related toxicity after receiving axi-cel. Six tNFL patients received ibrutinib concurrently with tisa-cel, with 1 case of grade ≥3 CRS/ICANS that rapidly resolved and no other severe toxicities. Our case series supports the use of CD19 CAR-T therapy in relapsed/refractory tCLL/SLL and tMZL. The concurrent use of ibrutinib and tisa-cel in tNFL was associated with manageable toxicity in tNFL.

A non-antibiotic-disrupted gut microbiome is associated with clinical responses to CD19-CAR-T cell cancer immunotherapy.

Increasing evidence suggests that the gut microbiome may modulate the efficacy of cancer immunotherapy. In a B cell lymphoma patient cohort from five centers in Germany and the United States (Germany, n = 66; United States, n = 106; total, n = 172), we demonstrate that wide-spectrum antibiotics treatment ('high-risk antibiotics') prior to CD19-targeted chimeric antigen receptor (CAR)-T cell therapy is associated with adverse outcomes, but this effect is likely to be confounded by an increased pretreatment tumor burden and systemic inflammation in patients pretreated with high-risk antibiotics. To resolve this confounding effect and gain insights into antibiotics-masked microbiome signals impacting CAR-T efficacy, we focused on the high-risk antibiotics non-exposed patient population. Indeed, in these patients, significant correlations were noted between pre-CAR-T infusion Bifidobacterium longum and microbiome-encoded peptidoglycan biosynthesis, and CAR-T treatment-associated 6-month survival or lymphoma progression. Furthermore, predictive pre-CAR-T treatment microbiome-based machine learning algorithms trained on the high-risk antibiotics non-exposed German cohort and validated by the respective US cohort robustly segregated long-term responders from non-responders. Bacteroides, Ruminococcus, Eubacterium and Akkermansia were most important in determining CAR-T responsiveness, with Akkermansia also being associated with pre-infusion peripheral T cell levels in these patients. Collectively, we identify conserved microbiome features across clinical and geographical variations, which may enable cross-cohort microbiome-based predictions of outcomes in CAR-T cell immunotherapy.

CYAD-01, an autologous NKG2D-based CAR T-cell therapy, in relapsed or refractory acute myeloid leukaemia and myelodysplastic syndromes or multiple myeloma (THINK): haematological cohorts of the dose escalation segment of a phase 1 trial.

BACKGROUND: CYAD-01 is an autologous chimeric antigen receptor (CAR) T-cell product based on the natural killer (NK) group 2D (NKG2D) receptor, which binds eight ligands that are overexpressed in a wide range of haematological malignancies but are largely absent on non-neoplastic cells. Initial clinical evaluation of a single infusion of CYAD-01 at a low dose in patients with relapsed or refractory acute myeloid leukaemia, myelodysplastic syndromes, and multiple myeloma supported the feasibility of the approach and prompted further evaluation of CYAD-01. The aim of the present study was to determine the safety and recommended phase 2 dosing of CYAD-01 administered without preconditioning or bridging chemotherapy. METHODS: The multicentre THINK study was an open-label, dose-escalation, phase 1 study for patients with relapsed or refractory acute myeloid leukaemia, myelodysplastic syndromes, or multiple myeloma, after at least one previous line of therapy. Patients were recruited from five hospitals in the USA and Belgium. The dose-escalation segment evaluated three dose levels: 3 × 108 (dose level one), 1 × 109 (dose level two), and 3 × 109 (dose level three) cells per infusion with a 3 + 3 Fibonacci study design using a schedule of three infusions at 2-week intervals followed by potential consolidation treatment consisting of three additional infusions. The occurrence of dose-limiting toxicities post-CYAD-01 infusion was assessed as the primary endpoint in the total treated patient population. The trial was registered with ClinicalTrials.gov, NCT03018405, and EudraCT, 2016-003312-12, and has been completed. FINDINGS: Between Feb 6, 2017, and Oct 9, 2018, 25 patients were registered in the haematological dose-escalation segment. Seven patients had manufacturing failure for insufficient yield and two had screening failure. 16 patients were treated with CYAD-01 (three with multiple myeloma and three with acute myeloid leukaemia at dose level one; three with acute myeloid leukaemia at dose level two; and six with acute myeloid leukaemia and one with myelodysplastic syndromes at dose level three). Median follow-up was 118 days (IQR 46-180). Seven patients (44%) had grade 3 or 4 treatment-related adverse events. In total, five patients (31%) had grade 3 or 4 cytokine release syndrome across all dose levels. One dose-limiting toxicity of cytokine release syndrome was reported at dose level three. No treatment-related deaths occurred, and the maximum tolerated dose was not reached. Three (25%) of 12 evaluable patients with relapsed or refractory acute myeloid leukaemia or myelodysplastic syndromes had an objective response. Among responders, two patients with acute myeloid leukaemia proceeded to allogeneic haematopoietic stem-cell transplantation (HSCT) after CYAD-01 treatment, with durable ongoing remissions (5 and 61 months). INTERPRETATION: Treatment with a multiple CYAD-01 infusion schedule without preconditioning is well tolerated and shows anti-leukaemic activity, although without durability outside of patients bridged to allogeneic HSCT. These phase 1 data support the proof-of-concept of targeting NKG2D ligands by CAR T-cell therapy. Further clinical studies with NKG2D-based CAR T-cells are warranted, potentially via combinatorial antigen targeted approaches, to improve anti-tumour activity. FUNDING: Celyad Oncology.

Human Effectors of Acute and Chronic GVHD Overexpress CD83 and Predict Mortality.

PURPOSE: Acute and chronic GVHD remain major causes of transplant-related morbidity and mortality (TRM) after allogeneic hematopoietic cell transplantation (alloHCT). We have shown CD83 chimeric antigen receptor (CAR) T cells prevent GVHD and kill myeloid leukemia cell lines. In this pilot study, we investigate CD83 expression on GVHD effector cells, correlate these discoveries with clinical outcomes, and evaluate critical therapeutic implications for transplant recipients. EXPERIMENTAL DESIGN: CD83 expression was evaluated among circulating CD4+ T cells, B-cell subsets, T follicular helper (Tfh) cells, and monocytes from patients with/without acute or chronic GVHD (n = 48 for each group), respectively. CD83 expression was correlated with survival, TRM, and relapse after alloHCT. Differential effects of GVHD therapies on CD83 expression was determined. RESULTS: CD83 overexpression on CD4+ T cells correlates with reduced survival and increased TRM. Increased CD83+ B cells and Tfh cells, but not monocytes, are associated with poor posttransplant survival. CD83 CAR T eliminate autoreactive CD83+ B cells isolated from patients with chronic GVHD, without B-cell aplasia as observed with CD19 CAR T. We demonstrate robust CD83 antigen density on human acute myeloid leukemia (AML), and confirm potent antileukemic activity of CD83 CAR T in vivo, without observed myeloablation. CONCLUSIONS: CD83 is a promising diagnostic marker of GVHD and warrants further investigation as a therapeutic target of both GVHD and AML relapse after alloHCT.

Large Scale Ex Vivo Expansion of γδ T cells Using Artificial Antigen-presenting Cells.

Higher γδ T cell counts in patients with malignancies are associated with better survival. However, γδ T cells are rare in the blood and functionally impaired in patients with malignancies. Promising results are reported on the treatment of various malignancies with in vivo expansion of autologous γδ T cells using zoledronic acid (zol) and interleukin-2 (IL-2). Here we demonstrated that zol and IL-2, in combination with a novel genetically engineered K-562 CD3scFv/CD137L/CD28scFv/IL15RA quadruplet artificial antigen-presenting cell (aAPC), efficiently expand allogeneic donor-derived γδ T cells using a Good Manufacturing Practice (GMP) compliant protocol sufficient to achieve cell doses for future clinical use. We achieved a 633-fold expansion of γδ T cells after day 10 of coculture with aAPC, which exhibited central (47%) and effector (43%) memory phenotypes. In addition, >90% of the expanded γδ T cells expressed NKG2D, although they have low cell surface expression of PD1 and LAG3 inhibitory checkpoint receptors. In vitro real-time cytotoxicity analysis showed that expanded γδ T cells were effective in killing target cells. Our results demonstrate that large-scale ex vivo expansion of donor-derived γδ T cells in a GMP-like setting can be achieved with the use of quadruplet aAPC and zol/IL-2 for clinical application.

Outcomes of CD19-Targeted Chimeric Antigen Receptor T Cell Therapy for Patients with Reduced Renal Function Including Dialysis.

Patients with renal impairment (RI) are typically excluded from trials evaluating chimeric antigen receptor (CAR) T cell therapies. We evaluated the outcomes of patients with RI receiving standard of care (SOC) CAR T cell therapy for relapsed/refractory (R/R) diffuse large B cell lymphoma (DLBCL). In this retrospective, single-center cohort study of patients with R/R DLBCL treated with SOC axicabtagene ciloleucel (axi-cel) or tisagenlecleucel (tisa-cel) after 2 or more prior lines of therapy, renal and survival outcomes were compared based on RI and fludarabine dose reduction (DR) status. RI was defined by an estimated glomerular filtration rate <60 mL/min/1.73 m2 as determined by the Modification of Diet in Renal Disease equation using day -5 creatinine (Cr) values. Acute kidney injury (AKI) was identified and graded using standard Kidney Disease: Improving Global Outcomes criteria. Renal recovery was considered to occur if Cr was within .2 mg/mL of baseline by day +30. Fludarabine was considered DR if given at <90% of the recommended Food and Drug Administration label dose. Among 166 patients treated with CAR T cell therapy were 17 patients (10.2%) with baseline RI and 149 (89.8%) without RI. After CAR T cell infusion, the incidence of any grade AKI was not significantly different between patients with baseline RI and those without RI (42% versus 21%; P = .08). Similarly, severe grade 2/3 AKI was seen in 1 of 17 patients (5.8%) with baseline RI and in 11 of 149 patients (7.3%) without RI (P = 1). Decreased renal perfusion (28 of 39; 72%) was the most common cause of AKI, with cytokine release syndrome (CRS) contributing to 17 of 39 AKIs (44%). Progression-free survival (PFS) and overall survival (OS) did not differ between patients with RI and those without RI or between those who received standard-dose fludarabine and those who received reduced-dose fludarabine. In contrast, patients with AKI had worse clinical outcomes than those without AKI (multivariable PFS: hazard ratio [HR], 2.1; 95% confidence interval [CI], 1.2 to 3.7; OS: HR, 3.9; 95% CI, 2.1 to 7.4). Notably, peak inflammatory cytokine levels were higher in patients who experienced AKI. Finally, we describe 2 patients with end-stage renal disease (ESRD) on dialysis who received lymphodepletion and CAR T cell therapy. Baseline renal function did not affect renal or efficacy outcomes after CAR T cell therapy in DLBCL. On the other hand, patients with AKI went on to experience worse clinical outcomes. AKI was commonly related to CRS and high peak inflammatory cytokine levels. CAR T cell therapy is feasible in patients with ESRD and requires careful planning of lymphodepletion.

Early cytopenias and infections after standard of care idecabtagene vicleucel in relapsed or refractory multiple myeloma.

Idecabtagene vicleucel (ide-cel) was FDA-approved in March 2021 for the treatment of relapsed/refractory multiple myeloma after 4 lines of therapy. On the KarMMa trial, grade ≥ 3 cytopenias and infections were common. We sought to characterize cytopenias and infections within 100 days after ide-cel in the standard-of-care (SOC) setting. This multi-center retrospective study included 52 patients who received SOC ide-cel; 47 reached day-90 follow-up. Data were censored at day 100. Grade ≥ 3 cytopenia was present among 65% of patients at day 30 and 40% of patients at day 90. Granulocyte colony stimulating factor (G-CSF) was administered to 88%, packed red blood cell transfusions to 63%, platelet transfusions to 42%, thrombopoietin (TPO) agonists to 21%, intravenous immunoglobulin to 13%, and CD34+ stem cell boosts to 8%. At day 100, 19% and 13% of patients had ongoing use of TPO agonists and G-CSF, respectively. Infections occurred in 54% of patients and were grade ≥ 3 in 23%. Earlier infections in the first 30 days were typically bacterial (68%) and severe (50%). Later infections between days 31 and 100 were 50% bacterial and 42% viral; only 13% were grade ≥ 3. On univariate analysis, high pre-CAR-T marrow myeloma burden (≥ 50%), circulating plasma cells at pre-lymphodepletion (LD), and grade ≥ 3 anemia at pre-LD were associated with grade ≥ 3 cytopenia at both days 30 and 90. Longer time from last bridging treatment to LD was the only significant risk factor for infection.

Indomethacin-induced oxidative stress enhances death receptor 5 signaling and sensitizes tumor cells to adoptive T-cell therapy.

BACKGROUND: Adoptive cell therapy (ACT) using genetically modified T cells has evolved into a promising treatment option for patients with cancer. However, even for the best-studied and clinically validated CD19-targeted chimeric antigen receptor (CAR) T-cell therapy, many patients face the challenge of lack of response or occurrence of relapse. There is increasing need to improve the efficacy of ACT so that durable, curative outcomes can be achieved in a broad patient population. METHODS: Here, we investigated the impact of indomethacin (indo), a non-steroidal anti-inflammatory drug (NSAID), on the efficacy of ACT in multiple preclinical models. Mice with established B-cell lymphoma received various combinations of preconditioning chemotherapy, infusion of suboptimal dose of tumor-reactive T cells, and indo administration. Donor T cells used in the ACT models included CD4+ T cells expressing a tumor-specific T cell receptor (TCR) and T cells engineered to express CD19CAR. Mice were monitored for tumor growth and survival. The effects of indo on donor T cell phenotype and function were evaluated. The molecular mechanisms by which indo may influence the outcome of ACT were investigated. RESULTS: ACT coupled with indo administration led to improved tumor growth control and prolonged mouse survival. Indo did not affect the activation status and tumor infiltration of the donor T cells. Moreover, the beneficial effect of indo in ACT did not rely on its inhibitory effect on the immunosuppressive cyclooxygenase 2 (COX2)/prostaglandin E2 (PGE2) axis. Instead, indo-induced oxidative stress boosted the expression of death receptor 5 (DR5) in tumor cells, rendering them susceptible to donor T cells expressing TNF-related apoptosis-inducing ligand (TRAIL). Furthermore, the ACT-potentiating effect of indo was diminished against DR5-deficient tumors, but was amplified by donor T cells engineered to overexpress TRAIL. CONCLUSION: Our results demonstrate that the pro-oxidative property of indo can be exploited to enhance death receptor signaling in cancer cells, providing rationale for combining indo with genetically modified T cells to intensify tumor cell killing through the TRAIL-DR5 axis. These findings implicate indo administration, and potentially similar use of other NSAIDs, as a readily applicable and cost-effective approach to augment the efficacy of ACT.

Clonal Hematopoiesis Is Associated with Increased Risk of Severe Neurotoxicity in Axicabtagene Ciloleucel Therapy of Large B-Cell Lymphoma.

To explore the role of clonal hematopoiesis (CH) in chimeric antigen receptor (CAR) T-cell therapy outcomes, we performed targeted deep sequencing on buffy coats collected during the 21 days before lymphodepleting chemotherapy from 114 large B-cell lymphoma patients treated with anti-CD19 CAR T cells. We detected CH in 42 (36.8%) pretreatment samples, most frequently in PPM1D (19/114) and TP53 (13/114) genes. Grade ≥3 immune effector cell-associated neurotoxicity syndrome (ICANS) incidence was higher in CH-positive patients than CH-negative patients (45.2% vs. 25.0%, P = 0.038). Higher toxicities with CH were primarily associated with DNMT3A, TET2, and ASXL1 genes (DTA mutations). Grade ≥3 ICANS (58.9% vs. 25%, P = 0.02) and ≥3 cytokine release syndrome (17.7% vs. 4.2%, P = 0.08) incidences were higher in DTA-positive than in CH-negative patients. The estimated 24-month cumulative incidence of therapy-related myeloid neoplasms after CAR T-cell therapy was higher in CH-positive than CH-negative patients [19% (95% CI, 5.5-38.7) vs. 4.2% (95% CI, 0.3-18.4), P = 0.028]. SIGNIFICANCE: Our study reveals that CH mutations, especially those associated with inflammation (DNMT3A, TET2, and ASXL1), are associated with severe-grade neurotoxicities in lymphoma patients receiving anti-CD19 CAR T-cell therapy. Further studies to investigate the mechanisms and interventions to improve toxicities in the context of CH are warranted. See related content by Uslu and June, p. 382. This article is highlighted in the In This Issue feature, p. 369.

Whole-genome sequencing reveals complex genomic features underlying anti-CD19 CAR T-cell treatment failures in lymphoma.

CD19-directed chimeric antigen receptor (CAR-19) T cells are groundbreaking immunotherapies approved for use against large B-cell lymphomas. Although host inflammatory and tumor microenvironmental markers associate with efficacy and resistance, the tumor-intrinsic alterations underlying these phenomena remain undefined. CD19 mutations associate with resistance but are uncommon, and most patients with relapsed disease retain expression of the wild-type receptor, implicating other genomic mechanisms. We therefore leveraged the comprehensive resolution of whole-genome sequencing to assess 51 tumor samples from 49 patients with CAR-19-treated large B-cell lymphoma. We found that the pretreatment presence of complex structural variants, APOBEC mutational signatures, and genomic damage from reactive oxygen species predict CAR-19 resistance. In addition, the recurrent 3p21.31 chromosomal deletion containing the RHOA tumor suppressor was strongly enriched in patients for whom CAR T-cell therapy failed. Pretreatment reduced expression or monoallelic loss of CD19 did not affect responses, suggesting CAR-19 therapy success and resistance are related to multiple mechanisms. Our study showed that tumor-intrinsic genomic alterations are key among the complex interplay of factors that underlie CAR-19 efficacy and resistance for large B-cell lymphomas.

CD3 engagement as a new strategy for allogeneic "off-the-shelf" T cell therapy.

Allogeneic "off-the-shelf" (OTS) chimeric antigen receptor T cells (CAR-T cells) hold promise for more accessible CAR-T therapy. Here, we report a novel and simple way to make allogeneic OTS T cells targeting cancer. By engineering T cells with a bispecific T cell engager (BiTE), both TCRαß and CD3ε expression on the T cell surface are dramatically reduced. BiTE-engineered T (BiTE-T) cells show reduced reaction to TCR stimulation in vitro and have low risk of graft-versus-host disease (GvHD) in vivo. BiTE-T cells down-regulated CD3ε/TCRαß on bystander T cells by releasing BiTEs. BiTE-T cells produce much fewer cytokines and are comparable to CAR-T cells on anti-cancer efficacy in xenograft mouse models with pre-existing HLA-mismatched T cells. Co-expressing co-stimulatory factors or T cell-promoting cytokines enhanced BiTE-T cells. Our study suggests CD3ε engagement could be a new strategy for allogeneic T cell therapy worthy of further evaluation.

4-1BB and optimized CD28 co-stimulation enhances function of human mono-specific and bi-specific third-generation CAR T cells.

BACKGROUND: Co-stimulatory signals regulate the expansion, persistence, and function of chimeric antigen receptor (CAR) T cells. Most studies have focused on the co-stimulatory domains CD28 or 4-1BB. CAR T cell persistence is enhanced by 4-1BB co-stimulation leading to nuclear factor kappa B (NF-κB) signaling, while resistance to exhaustion is enhanced by mutations of the CD28 co-stimulatory domain. METHODS: We hypothesized that a third-generation CAR containing 4-1BB and CD28 with only PYAP signaling motif (mut06) would provide beneficial aspects of both. We designed CD19-specific CAR T cells with either 4-1BB or mut06 together with the combination of both and evaluated their immune-phenotype, cytokine secretion, real-time cytotoxic ability and polyfunctionality against CD19-expressing cells. We analyzed lymphocyte-specific protein tyrosine kinase (LCK) recruitment by the different constructs by immunoblotting. We further determined their ability to control growth of Raji cells in NOD scid gamma (NSG) mice. We also engineered bi-specific CARs against CD20/CD19 combining 4-1BB and mut06 and performed repeated in vitro antigenic stimulation experiments to evaluate their expansion, memory phenotype and phenotypic (PD1+CD39+) and functional exhaustion. Bi-specific CAR T cells were transferred into Raji or Nalm6-bearing mice to study their ability to eradicate CD20/CD19-expressing tumors. RESULTS: Co-stimulatory domains combining 4-1BB and mut06 confers CAR T cells with an increased central memory phenotype, expansion, and LCK recruitment to the CAR. This enhanced function was dependent on the positioning of the two co-stimulatory domains. A bi-specific CAR targeting CD20/CD19, incorporating 4-1BB and mut06 co-stimulation, showed enhanced antigen-dependent in vitro expansion with lower exhaustion-associated markers. Bi-specific CAR T cells exhibited improved in vivo antitumor activity with increased persistence and decreased exhaustion. CONCLUSION: These results demonstrate that co-stimulation combining 4-1BB with an optimized form of CD28 is a valid approach to optimize CAR T cell function. Cells with both mono-specific and bi-specific versions of this design showed enhanced in vitro and in vivo features such as expansion, persistence and resistance to exhaustion. Our observations validate the approach and justify clinical studies to test the efficacy and safety of this CAR in patients.