Siltuximab for Chimeric Antigen Receptor T-Cell Therapy Related CRS and ICANS - A Multicenter Retrospective Analysis.

Chimeric Antigen Receptor T-Cell therapies (CAR-T) are effective in many hematologic malignancies; however, adverse events including cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS) can affect a significant number of patients. Those who develop refractory CRS or ICANS have few treatment options. Siltuximab, a monoclonal antibody binding circulating IL-6, has been proposed to have clinical activity in both CRS and ICANS. We conducted a multi-center retrospective analysis of siltuximab treatment for CRS and ICANS following CAR-T cell therapy in a real-world cohort from six academic centers. Fifty-four patients were evaluated. Sixteen patients had CRS previously treated with tocilizumab and 17 patients had ICANS previously treated with steroids. Of the all the patients with CRS at the time of siltuximab, 75% had improvement in CRS grade. Of the all the patients with ICANS at the time of siltuximab, 60% had improvement in ICANS grade. To our knowledge, this is the largest cohort of patients treated with siltuximab for CRS and/or ICANS following CAR-T. Siltuximab appeared to be effective for both CRS and ICANS, including previously treated toxicities. These data support the use of siltuximab in CRS and ICANS as well as provide rationale for future prospective studies.

Stem-like CD8+ T cells in cancer.

Stem-like CD8+ T cells (TSL) are a subset of immune cells with superior persistence and antitumor immunity. They are TCF1+ PD-1+ and important for the expansion of tumor specific CD8+ T cells in response to checkpoint blockade immunotherapy. In acute infections, naïve CD8+ T cells differentiate into effector and memory CD8+ T cells; in cancer and chronic infections, persistent antigen stimulation can lead to T cell exhaustion. Recent studies have highlighted the dichotomy between late dysfunctional (or exhausted) T cells (TLD) that are TCF1- PD-1+ and self-renewing TCF1+ PD-1+ TSL from which they derive. TCF1+ TSL cells are considered to have stem cell-like properties akin to memory T cell populations and can give rise to cytotoxic effector and transitory T cell phenotypes (TTE) which mediate tumor control. In this review, we will discuss recent advances made in research on the formation and expansion of TSL, as well as distinct niches required for their differentiation and maintenance in the setting of cancer. We will also discuss potential strategies to generate these cells, with clinical implications for stemness enhancement in vaccine design, immune checkpoint blockade (ICB), and adoptive T cell therapies.

SOHO State of the Art Updates and Next Questions Updates on Building Your CAR-T Cell Program.

Chimeric antigen receptor T-cell (CAR-T) therapy has significantly impacted treatment algorithms and clinical outcomes for a variety of patients with hematologic malignancies over the past decade. The field of cellular immunotherapy is currently experiencing a rapid expansion of the number of patients eligible for CAR-T therapies as approvals are being seen in earlier lines of therapy. With the expanded patients eligible for these therapies, more treatment centers will be necessary to keep up with demand. Building a cellular therapy program can be a daunting task, and therefore, we present our experience with building a clinical cellular therapy program.

Postinfusion PD-1+ CD8+ CAR T cells identify patients responsive to CD19 CAR T-cell therapy in non-Hodgkin lymphoma.

ABSTRACT: Chimeric antigen receptor (CAR) T-cell therapy has revolutionized treatment for relapsed/refractory B-cell non-Hodgkin lymphoma (NHL). Robust biomarkers and a complete understanding of CAR T-cell function in the postinfusion phase remain limited. Here, we used a 37-color spectral flow cytometry panel to perform high dimensional single-cell analysis of postinfusion samples in 26 patients treated with CD28 costimulatory domain containing commercial CAR T cells for NHL and focused on computationally gated CD8+ CAR T cells. We found that the presence of postinfusion Programmed cell death protein 1 (PD-1)+ CD8+ CAR T cells at the day 14 time point highly correlated with the ability to achieve complete response (CR) by 6 months. Further analysis identified multiple subtypes of CD8+ PD-1+ CAR T cells, including PD-1+ T cell factor 1 (TCF1)+ stem-like CAR T cells and PD-1+ T-cell immunoglobulin and mucin-domain containing-3 (TIM3)+ effector-like CAR T cells that correlated with improved clinical outcomes such as response and progression-free survival. Additionally, we identified a subset of PD-1+ CD8+ CAR+ T cells with effector-like function that was increased in patients who achieved a CR and was associated with grade 3 or higher immune effector cell-associated neurotoxicity syndrome. Here, we identified robust biomarkers of response to CD28 CAR T cells and highlight the importance of PD-1 positivity in CD8+ CAR T cells after infusion in achieving CR.

A novel CAR-T cell product targeting CD74 is an effective therapeutic approach in preclinical mantle cell lymphoma models.

BACKGROUND: Mantle cell lymphoma (MCL) is a rare B-cell non-Hodgkin lymphoma subtype which remains incurable despite multimodal approach including chemoimmunotherapy followed by stem cell transplant, targeted approaches such as the BTK inhibitor ibrutinib, and CD19 chimeric antigen receptor (CAR) T cells. CD74 is a nonpolymorphic type II integral membrane glycoprotein identified as an MHC class II chaperone and a receptor for macrophage migration inhibitory factor. Our group previously reported on CD74's abundant expression in MCL and its ability to increase via pharmacological inhibition of autophagosomal degradation. Milatuzumab, a fully humanized anti-CD74 monoclonal antibody, demonstrated significant activity in preclinical lymphoma models but failed to provide meaningful benefits in clinical trials mainly due to its short half-life. We hypothesized that targeting CD74 using a CAR-T cell would provide potent and durable anti-MCL activity. METHODS: We engineered a second generation anti-CD74 CAR with 4-1BB and CD3ζ signaling domains (74bbz). Through in silico and rational mutagenesis on the scFV domain, the 74bbz CAR was functionally optimized for superior antigen binding affinity, proliferative signaling, and cytotoxic activity against MCL cells in vitro and in vivo. RESULTS: Functionally optimized 74bbz CAR-T cells (clone 42105) induced significant killing of MCL cell lines, and primary MCL patient samples including one relapse after commercial CD19 CAR-T cell therapy with direct correlation between antigen density and cytotoxicity. It significantly prolonged the survival of an animal model established in NOD-SCIDγc-/- (NSG) mice engrafted with a human MCL cell line Mino subcutaneously compared to controls. Finally, while CD74 is also expressed on normal immune cell subsets, treatment with 74bbz CAR-T cells resulted in minimal cytotoxicity against these cells both in vitro and in vivo. CONCLUSIONS: Targeting CD74 with 74bbz CAR-T cells represents a new cell therapy to provide a potent and durable and anti-MCL activity.

Selective suppression of de novo SARS-CoV-2 vaccine antibody responses in patients with cancer on B cell-targeted therapy.

We assessed vaccine-induced antibody responses to the SARS-CoV-2 ancestral virus and Omicron variant before and after booster immunization in 57 patients with B cell malignancies. Over one-third of vaccinated patients at the pre-booster time point were seronegative, and these patients were predominantly on active cancer therapies such as anti-CD20 monoclonal antibody. While booster immunization was able to induce detectable antibodies in a small fraction of seronegative patients, the overall booster benefit was disproportionately evident in patients already seropositive and not receiving active therapy. While ancestral virus- and Omicron variant-reactive antibody levels among individual patients were largely concordant, neutralizing antibodies against Omicron tended to be reduced. Interestingly, in all patients, including those unable to generate detectable antibodies against SARS-CoV-2 spike, we observed comparable levels of EBV- and influenza-reactive antibodies, demonstrating that B cell-targeting therapies primarily impair de novo but not preexisting antibody levels. These findings support rationale for vaccination before cancer treatment.

Allogeneic transplant following CAR T-cell therapy for large B-cell lymphoma.

Allogeneic hematopoietic cell transplantation (alloHCT) can potentially salvage large B-cell lymphoma (LBCL) patients experiencing treatment failure after chimeric antigen receptor T-cell therapy (CAR T). Nonetheless, data on the efficacy and toxicities of alloHCT after receipt of CAR T are limited. We report a multicenter retrospective study assessing the safety, toxicities, and outcomes of alloHCT in LBCL patients following CAR T failure. Eighty-eight patients with relapsed, refractory LBCL received an alloHCT following anti-CD19 CAR T failure. The median number of lines of therapy between CAR T infusion and alloHCT was one (range, 0-7). Low intensity conditioning was used in 77% (n=68) and peripheral blood was the most common graft source (86%, n=76). The most common donor types were matched unrelated donor (39%), followed by haploidentical (30%) and matched related donor (26%). Median follow-up of survivors was 15 months (range, 1-72). One-year overall survival, progression-free survival, and graft-versus-host disease-free relapse-free survival were 59%, 45%, and 39% respectively. One-year non-relapse mortality and progression/relapse were 22% and 33% respectively. On multivariate analysis, <2 lines of intervening therapy between CAR T and alloHCT and complete response at time of alloHCT were associated with better outcomes. In conclusion, alloHCT after CAR T failure can provide durable remissions in a subset of patients.

Peri-CAR-T practice patterns and survival predictors for all CAR-T patients and post-CAR-T failure in aggressive B-NHL.

Most patients receiving chimeric antigen receptor T-cell therapy (CAR-T) for aggressive B-cell non-Hodgkin lymphoma (B-NHL) do not experience a durable remission. Several novel agents are approved to treat relapsed, refractory aggressive B-NHL; however, it remains unclear how to sequence these therapies pre- and post-CAR-T. We conducted a multicenter retrospective analysis to describe peri-CAR-T practice patterns and survival predictors for patients receiving CD19-directed CAR-T. Patients (n = 514) from 13 centers treated with CAR-T for B-NHL between 2015-2021 were included in the study. Survival curves were constructed using Kaplan-Meier method. Multivariate Cox regression analysis was used to determine the impact of the variables on survival outcomes. For all patients receiving CAR-T, a greater number of lines of therapy pre-CAR-T apheresis and bridging therapy were predictive of inferior progression-free survival (PFS) and overall survival (OS). The median PFS and OS from the time of CAR-T cell infusion were 7.6 and 25.6 months, respectively. From the time of progression post-CAR-T, the median OS was 5.5 months. The median PFS of treatments administered in the first-line post-CAR-T failure was 2.8 months. Patients with refractory disease on day 30 had inferior OS and were less likely to receive subsequent treatment(s) than other patients with CAR-T failure. Allogeneic hematopoietic cell transplantation for selected patients at any time following CAR-T failure led to durable responses in over half of patients at 1 year. These data provide a benchmark for future clinical trials in patients with post-CAR-T cell progression, which remains an unmet clinical need.

Recent Advances and Challenges in Cancer Immunotherapy.

Cancer immunotherapy has revolutionized the field of oncology in recent years. Harnessing the immune system to treat cancer has led to a large growth in the number of novel immunotherapeutic strategies, including immune checkpoint inhibition, chimeric antigen receptor T-cell therapy and cancer vaccination. In this review, we will discuss the current landscape of immuno-oncology research, with a focus on elements that influence immunotherapeutic outcomes. We will also highlight recent advances in basic aspects of tumor immunology, in particular, the role of the immunosuppressive cells within the tumor microenvironment in regulating antitumor immunity. Lastly, we will discuss how the understanding of basic tumor immunology can lead to the development of new immunotherapeutic strategies.

Assessment of Salvage Regimens Post-Chimeric Antigen Receptor T Cell Therapy for Patients with Diffuse Large B Cell Lymphoma.

Anti-CD19 chimeric antigen receptor T cell therapy (CAR19) represents a critical treatment modality for patients with relapsed/refractory (R/R) diffuse large B-cell lymphoma (DLBCL). However, the majority of patients subsequently experience disease progression following CAR19, and data are limited on assessing the best salvage regimen for these patients. This study aimed to evaluate outcomes in R/R DLBCL patients with progressive disease post-CAR19 and to assess variables that predict response to salvage therapy. We performed a retrospective analysis of all patients with DLBCL who received CAR19 at our institution between January 2018 and February 2021, collecting data on demographic characteristics, disease characteristics, best response to CAR19, date of relapse or progression, and first salvage therapy and response to salvage. We analyzed patients according to whether they responded to CAR19 (responders) or did not (nonresponders). Salvage regimens were classified into 6 groups for analysis. Primary endpoints included overall survival (OS) and progression-free survival (PFS), calculated using the Kaplan-Meier method. Cox models were fit to evaluate the effect of prognostic factors. Among the 120 patients who received CAR19 during the analysis period were 69 responders who achieved a complete or partial response to CAR19 and 51 nonresponders, including 44 with stable or progressive disease and 7 who died before assessment. Thirty responders relapsed and 26 received salvage therapy, and 24 nonresponders received salvage therapy. The primary salvage regimens included lenalidomide-based regimens (n = 17; 34%), BTKi (n = 10; 20%), checkpoint inhibitor-based (n = 7; 14%), chemo-immunotherapy (n = 5; 10%), allogeneic hematopoietic stem cell transplantation (n = 5; 10%), and others (n = 6; 12%). There was no significant difference in OS based on salvage regimen (P = .4545). Responders who received salvage therapy had significantly longer OS than nonresponders (median OS not reached versus 10.9 months; P = .0187), and response to CAR19 and elevated lactate dehydrogenase level at time of salvage treatment were the only two statistically significant prognostic factors after accounting for other variables. Responders to CAR19 had significantly better outcomes with salvage therapy compared with nonresponders to CAR19. There was no significant difference in outcomes based on salvage regimen. Future research is needed to assess the best salvage regimen post-CAR19 failure.

Impact of diagnostic genetics on remission MRD and transplantation outcomes in older patients with AML.

Older patients with acute myeloid leukemia (AML) have high relapse risk and poor survival after allogeneic hematopoietic cell transplantation (HCT). Younger patients may receive myeloablative conditioning to mitigate relapse risk associated with high-risk genetics or measurable residual disease (MRD), but older adults typically receive reduced-intensity conditioning (RIC) to limit toxicity. To identify factors that drive HCT outcomes in older patients, we performed targeted mutational analysis (variant allele fraction ≥2%) on diagnostic samples from 295 patients with AML aged ≥60 years who underwent HCT in first complete remission, 91% of whom received RIC, and targeted duplex sequencing at remission in a subset comprising 192 patients. In a multivariable model for leukemia-free survival (LFS) including baseline genetic and clinical variables, we defined patients with low (3-year LFS, 85%), intermediate (55%), high (35%), and very high (7%) risk. Before HCT, 79.7% of patients had persistent baseline mutations, including 18.3% with only DNMT3A or TET2 (DT) mutations and 61.4% with other mutations (MRD positive). In univariable analysis, MRD positivity was associated with increased relapse and inferior LFS, compared with DT and MRD-negative mutations. However, in a multivariable model accounting for baseline risk, MRD positivity had no independent impact on LFS, most likely because of its significant association with diagnostic genetic characteristics, including MDS-associated gene mutations, TP53 mutations, and high-risk karyotype. In summary, molecular associations with MRD positivity and transplant outcomes in older patients with AML are driven primarily by baseline genetics, not by mutations present in remission. In this group of patients, where high-intensity conditioning carries substantial risk of toxicity, alternative approaches to mitigating MRD-associated relapse risk are needed.

CAR T-cell therapy for B-cell lymphoma.

Chimeric antigen receptor-modified (CAR) T-cell therapy targeting CD19 has revolutionized the treatment of relapsed or refractory B-cell lymphomas. Based on unprecedented response rates and durability of response in high risk B-cell lymphoma patients, anti-CD19 CAR T-cell therapy was rapidly approved by the FDA for a variety of lymphoma subtypes. Anti-CD19 CAR T-cell therapy is now considered standard of care for patients with relapsed or refractory (R/R) aggressive non-Hodgkin's Lymphoma (NHL) after 2 or more lines of therapy. Three second-generation anti-CD19 CAR T-cell products have been FDA approved for R/R aggressive B-cell lymphoma and FDA approval has been obtained for Mantle Cell Lymphoma and Follicular lymphoma as well. This has ensured broad access to CAR T-cell therapy for patients with NHL and new real-world trials have helped confirm feasibility of CAR T-cell therapy for a broad patient population. The emergence of CAR T-cell therapy will likely provide a new patient population who is status post anti-CD19 CAR T-cell therapy. Investigation of mechanisms of failure of CAR T-cell therapy and clinical trials to study strategies to address this are thus required. Here we provide a thorough review on the use of the FDA approved anti-CD19 CAR T-cell products axicabtagene ciloleucel, tisagenlecleucel, and lisocabtagene maraleucel in patients with indolent or aggressive B-cell lymphoma, and touch on mechanisms of failure of CAR T-cell therapy and potential approaches which are currently under investigation to address this.

Early toxicity and clinical outcomes after chimeric antigen receptor T-cell (CAR-T) therapy for lymphoma.

BACKGROUND: Chimeric antigen receptor T-cell (CAR-T) infusion is associated with early toxicity. Yet, whether early toxicity development holds ramifications for long-term outcomes is unknown. METHODS: From a large cohort of consecutive adult patients treated with CAR-T therapies for relapsed or refractory lymphomas from 2016 to 2019, we assessed progression-free survival (PFS), by toxicity development (cytokine release syndrome (CRS), neurotoxicity, or cardiotoxicity]. We also assessed the relationship of toxicity development to objective disease response, and overall survival (OS). Multivariable regression was utilized to evaluate relationships between standard clinical and laboratory measures and disease outcomes. Differences in outcomes, by toxicity status, were also assessed via 30-day landmark analysis. Furthermore, we assessed the effects of early anti-CRS toxicity therapy use (at ≤grade 2 toxicity) on maximum toxicity grade observed, and long-term disease outcomes (PFS and OS). RESULTS: Overall, from 102 CAR-T-treated patients, 90 were identified as treated with single-agent therapy, of which 88.9% developed toxicity (80 CRS, 41 neurotoxicity, and 17 cardiotoxicity), including 28.9% with high-grade (≥3) events. The most common manifestations were hypotension at 96.6% and fever at 94.8%. Among patients with cardiac events, there was a non-significant trend toward a higher prevalence of concurrent or preceding high-grade (≥3) CRS. 50.0% required tocilizumab or corticosteroids. The median time to toxicity was 3 days; high grade CRS development was associated with cardiac and neurotoxicity. In multivariable regression, accounting for disease severity and traditional predictors of disease response, moderate (maximum grade 2) CRS development was associated with higher complete response at 1 year (HR: 2.34; p=0.07), and longer PFS (HR: 0.41; p=0.02, in landmark analysis), and OS (HR: 0.43; p=0.03). Among those with CRS, relative blood pressure (HR: 2.25; p=0.004), respectively, also associated with improved PFS. There was no difference in disease outcomes, or maximum toxicity grade (CRS, neurotoxicity, or cardiotoxicity) observed, based on the presence or absence of the use of early CRS-directed therapies. CONCLUSIONS: Among adult lymphoma patients, moderate toxicity manifest as grade 2 CRS after CAR-T infusion may associate with favorable clinical outcomes. Further studies are needed to confirm these findings.

Comorbidities Predict Inferior Survival in Patients Receiving Chimeric Antigen Receptor T Cell Therapy for Diffuse Large B Cell Lymphoma: A Multicenter Analysis.

Chimeric antigen receptor T cell (CAR-T) therapy is approved for treatment of relapsed/refractory (R/R) diffuse large B cell lymphoma (DLBCL). Here we evaluate whether comorbidities, calculated using the Cumulative Illness Rating Scale (CIRS), predict survival for these patients. A retrospective chart review was performed at 4 academic institutions. All patients who underwent leukapheresis for commercial CAR-T therapy for R/R DLBCL were included. CIRS scores were calculated at the time of leukapheresis. High comorbidity was defined as either CIRS ≥7 or the presence of severe impairment (CIRS 3/4 in ≥1 system; CIRS-3+). Progression-free survival (PFS) and overall survival (OS) were estimated using the Kaplan-Meier method, and differences in curves were detected by the log-rank test. A total of 130 patients were analyzed, 56.9% with CIRS ≥7 and 56.2% with CIRS-3+. After a median follow-up of 13 months, the median PFS was 6.7 months, and the median OS was not reached. On univariable analysis, Eastern Cooperative Oncology Group (ECOG) performance status (PS) was associated with inferior PFS (hazard ratio [HR], 1.45; 95% confidence interval [CI], 1.03-2.05; P = .03) and OS (HR, 1.76; 95% CI, 1.17-2.64; P = .007). Higher CIRS (CIRS ≥7 or CIRS-3+) was associated with inferior OS (HR, 2.12; 95%, CI, 1.06-4.22; P = .03) and a nonsignificant trend in worse PFS (HR, 1.45; 95% CI, .87-2.44; P = .16). In multivariable analyses, CIRS ≥7 or CIRS-3+ and ECOG PS maintained independent prognostic significance. Comorbidities as determined by CIRS and ECOG PS predict inferior survival in patients receiving CAR-T therapy for R/R DLBCL.

Management of relapsed/refractory marginal zone lymphoma: focus on ibrutinib.

Marginal zone lymphomas (MZLs) consist of a diverse family of malignancies, which are derived from B-cells. The disease subtypes are recognized extranodal, nodal, and splenic MZLs. The disease characteristics, clinical course, and treatment vary considerably based on the site of involvement. In 2017, the US Food and Drug Administration approved ibrutinib, a first in class Bruton's tyrosine kinase inhibitor that revolutionized the care of chronic lymphocytic leukemia patients; for, the treatment of relapsed/refractory MZL based on pivotal open-label Phase II trial demonstrated an overall response rate of 48%, with a complete response rate of 3%, median progression-free survival of 14.2 months, and median overall survival not yet reached at a median follow-up of 19.4 months. In this review, we aim to summarize the current conundrums in the management of MZL and the evolving role of ibrutinib in the treatment of MZL.

Toll-like receptor 3 is critical for coxsackievirus B4-induced type 1 diabetes in female NOD mice.

Group B coxsackieviruses (CVBs) are involved in triggering some cases of type 1 diabetes mellitus (T1DM). However, the molecular mechanism(s) responsible for this remain elusive. Toll-like receptor 3 (TLR3), a receptor that recognizes viral double-stranded RNA, is hypothesized to play a role in virus-induced T1DM, although this hypothesis is yet to be substantiated. The objective of this study was to directly investigate the role of TLR3 in CVB-triggered T1DM in nonobese diabetic (NOD) mice, a mouse model of human T1DM that is widely used to study both spontaneous autoimmune and viral-induced T1DM. As such, we infected female wild-type (TLR3(+/+)) and TLR3 knockout (TLR3(-/-)) NOD mice with CVB4 and compared the incidence of diabetes in CVB4-infected mice with that of uninfected counterparts. We also evaluated the islets of uninfected and CVB4-infected wild-type and TLR3 knockout NOD mice by immunohistochemistry and insulitis scoring. TLR3 knockout mice were markedly protected from CVB4-induced diabetes compared with CVB4-infected wild-type mice. CVB4-induced T-lymphocyte-mediated insulitis was also significantly less severe in TLR3 knockout mice compared with wild-type mice. No differences in insulitis were observed between uninfected animals, either wild-type or TLR3 knockout mice. These data demonstrate for the first time that TLR3 is 1) critical for CVB4-induced T1DM, and 2) modulates CVB4-induced insulitis in genetically prone NOD mice.