Emerging Strategies for the Prevention of Immune Toxicities Associated with T cell-Engaging Cancer Therapies.

SUMMARY: Immune-related toxicities including cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS) are common side effects of bispecific antibody and chimeric antigen receptor (CAR) T-cell therapies of hematologic malignancies. As anti-inflammatory therapy (the standard of care) is variably effective in mitigating these toxicities after onset, here we discuss emerging evidence for shifting the strategy from mitigation to prevention.

Druggable Targets in Cytokine Release Syndromes.

Bispecific T-cell engagers and chimeric antigen receptor T cells share the problem of eliciting acute systemic inflammation episodes known as cytokine release syndrome. Knowledge on the sequential waves of cytokines that can be neutralized with clinically available agents is crucial to prevent or treat this condition without jeopardizing the antitumor therapeutic outcome. See related article by Leclercq-Cohen et al., p. 4449.

Prevention and management of adverse events during treatment with bispecific antibodies and CAR T cells in multiple myeloma: a consensus report of the European Myeloma Network.

T-cell redirecting bispecific antibodies (BsAbs) and chimeric antigen receptor T cells (CAR T cells) have revolutionised multiple myeloma therapy, but adverse events such as cytokine release syndrome, immune effector cell-associated neurotoxicity syndrome (ICANS), cytopenias, hypogammaglobulinaemia, and infections are common. This Policy Review presents a consensus from the European Myeloma Network on the prevention and management of these adverse events. Recommended measures include premedication, frequent assessing for symptoms and severity of cytokine release syndrome, step-up dosing for several BsAbs and some CAR T-cell therapies; corticosteroids; and tocilizumab in the case of cytokine release syndrome. Other anti-IL-6 drugs, high-dose corticosteroids, and anakinra might be considered in refractory cases. ICANS often arises concomitantly with cytokine release syndrome. Glucocorticosteroids in increasing doses are recommended if needed, as well as anakinra if the response is inadequate, and anticonvulsants if convulsions occur. Preventive measures against infections include antiviral and antibacterial drugs and administration of immunoglobulins. Treatment of infections and other complications is also addressed.

Tocilizumab for Cytokine Release Syndrome Management After Haploidentical Hematopoietic Cell Transplantation With Post-Transplantation Cyclophosphamide-Based Graft-Versus-Host Disease Prophylaxis.

Cytokine release syndrome (CRS) is a common complication after haploidentical hematopoietic cell transplantation (HaploHCT). Severe CRS after haploHCT leads to higher risk of non-relapse mortality (NRM) and worse overall survival (OS). Tocilizumab (TOCI) is an interleukin-6 receptor inhibitor and is commonly used as first-line for CRS management after chimeric antigen receptor T cell therapy, but the impact of TOCI administration for CRS management on Haplo HCT outcomes is not known. In this single center retrospective analysis, we compared HCT outcomes in patients treated with or without TOCI for CRS management after HaploHCT with post-transplantation cyclophosphamide- (PTCy-) based graft-versus-host disease (GvHD) prophylaxis. Of the 115 patients eligible patients who underwent HaploHCT at City of Hope between 2019 to 2021 and developed CRS, we identified 11 patients who received tocilizumab for CRS management (TOCI). These patients were matched with 21 patients who developed CRS but did not receive tocilizumab (NO-TOCI) based on age at the time of HCT (≤64 years or >65 years or older), conditioning intensity (myeloablative versus reduced-intensity/nonmyeloablative), and CRS grading (1, 2, versus 3-4). Instead of 22 controls, we chose 21 patients because there was only 1 control matched with 1 TOCI treatment patient in 1 stratum. With only 11 patients in receiving tocilizumab for CRS treatment, matching with 21 patients who developed CRS but did not receive tocilizumab, we had 80% power to detect big differences (hazard ratio [HR] = 3.4 or higher) in transplantation outcomes using a 2-sided 0.05 test. The power would be reduced to about 20% to 30% if the difference was moderate (HR = 2.0) using the same test. No CRS-related deaths were recorded in either group. Median time to neutrophil engraftment was 21 days (range 16-43) in TOCI and 18 days (range 14-23) in NO-TOCI group (HR = 0.55; 95% confidence interval [CI] = 0.28-1.06, P = .08). Median time to platelet engraftment was 34 days (range 20-81) in TOCI and 28 days (range 12-94) in NO-TOCI group (HR = 0.56; 95% CI = 0.25-1.22, P = .19). Cumulative incidences of day 100 acute GvHD grades II-IV (P = .97) and grades III-IV (P = .47) were similar between the 2 groups. However, cumulative incidence of chronic GvHD at 1 year was significantly higher in patients receiving TOCI (64% versus 24%; P = .05). Rates of NRM (P = .66), relapse (P = .83), disease-free survival (P = .86), and overall survival (P = .73) were similar at 1 year after HCT between the 2 groups. Tocilizumab administration for CRS management after HaploHCT appears to be safe with no short-term adverse effect and no effect on relapse rate. However, the significantly higher cumulative incidence of chronic GvHD, negates the high efficacy of PTCy on GvHD prophylaxis in this patient population. Therefore using tocilizumab for CRS management in the HaploHCT population with PTCy maybe kept only for patients with severe CRS. The impact on such approach on long term outcome in HaploHCT with PTCy will need to be evaluated in a larger retrospective study or a prospective manner.

Glofitamab for Relapsed or Refractory Diffuse Large B-Cell Lymphoma.

BACKGROUND: The prognosis for patients with relapsed or refractory diffuse large B-cell lymphoma (DLBCL) is poor. Glofitamab is a bispecific antibody that recruits T cells to tumor cells. METHODS: In the phase 2 part of a phase 1-2 study, we enrolled patients with relapsed or refractory DLBCL who had received at least two lines of therapy previously. Patients received pretreatment with obinutuzumab to mitigate cytokine release syndrome, followed by fixed-duration glofitamab monotherapy (12 cycles total). The primary end point was complete response according to assessment by an independent review committee. Key secondary end points included duration of response, survival, and safety. RESULTS: Of the 155 patients who were enrolled, 154 received at least one dose of any study treatment (obinutuzumab or glofitamab). At a median follow-up of 12.6 months, 39% (95% confidence interval [CI], 32 to 48) of the patients had a complete response according to independent review. Results were consistent among the 52 patients who had previously received chimeric antigen receptor T-cell therapy (35% of whom had a complete response). The median time to a complete response was 42 days (95% CI, 42 to 44). The majority (78%) of complete responses were ongoing at 12 months. The 12-month progression-free survival was 37% (95% CI, 28 to 46). Discontinuation of glofitamab due to adverse events occurred in 9% of the patients. The most common adverse event was cytokine release syndrome (in 63% of the patients). Adverse events of grade 3 or higher occurred in 62% of the patients, with grade 3 or higher cytokine release syndrome in 4% and grade 3 or higher neurologic events in 3%. CONCLUSIONS: Glofitamab therapy was effective for DLBCL. More than half the patients had an adverse event of grade 3 or 4. (Funded by F. Hoffmann-La Roche; ClinicalTrials.gov number, NCT03075696.).

Emerging approaches for preventing cytokine release syndrome in CAR-T cell therapy.

Chimeric antigen receptor (CAR) T cells have demonstrated remarkable anti-tumor efficacy against hematological malignancies, such as leukemia and lymphoma. However, patients treated with CAR-T cells frequently experience cytokine release syndrome (CRS), one of the most life-threatening adverse events of the therapy induced by systemic concentrations of pro-inflammatory cytokines throughout the body. Immunosuppressants such as tocilizumab are currently administered to treat the onset and progression of CRS symptoms. In order to reduce the risk of CRS, newly designed next-generation CAR-T treatments are being developed for both hematopoietic malignancies and solid tumors. In this review, we discuss six classes of interesting approaches that control cytokine production of CAR-T cell therapy: adaptor-based strategies, orthogonal cytokine-receptor pairs, regulation of macrophage cytokine activity, autonomous neutralization of key cytokines, kill switches and methods of reversible suppression of CARs. With these strategies, future CAR-T cell therapies will be designed to preemptively inhibit CRS, minimize the patients' suffering, and maximize the number of benefiting patients.

Highlights of clinical and laboratory parameters among severe COVID-19 patients treated with tocilizumab: a retrospective observational study.

BACKGROUND: Coronavirus disease 2019 (COVID-19) can cause cytokine release syndrome (CRS), which leads to high mortality rates. Tocilizumab suppresses CRS by blocking the signal transduction of interleukin-6 (IL-6). OBJECTIVE: To evaluate the clinical and laboratory parameters associated with mortality among patients receiving tocilizumab treatment. DESIGN AND SETTING: Retrospective observational study conducted in the chest disease departments of two different training and research hospitals in the center of Ankara, Turkey. METHODS: Patients who were hospitalized and treated with tocilizumab in September 2020 were retrospectively analyzed. Their laboratory parameters and clinical characteristics were obtained from the hospital information system database. Comparative analyses were performed between the patients who died and the ones who survived. RESULTS: A total of 58 patients who received tocilizumab treatment were included in this study, among whom 35 (60.3%) died. There was no difference between the mortality and survival groups in terms of white blood cell (WBC), neutrophil, lymphocyte, ferritin or C-reactive protein (CRP) levels detected on admission. WBC, lymphocyte, neutrophil and CRP levels measured on the third and fifth days after tocilizumab administration were found to be significantly lower in the survival group (P < 0.05). In multiple logistic regression analysis, age and oxygen saturation were determined to be independent risk factors for mortality. CONCLUSION: Persistently high WBC, CRP and neutrophil levels and low lymphocyte levels could be considered to be valuable indicators of mortality among COVID-19 patients treated with tocilizumab. Age and low oxygen saturation are independent risk factors for mortality among patients receiving tocilizumab treatment.

A soluble DR5-Fc chimeric protein attenuates inflammatory responses induced by coronavirus MHV-A59 and SARS-CoV-2.

Mortality in coronavirus disease 2019 (COVID-19) patients has been linked to the presence of a "cytokine storm" induced by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, which involves elevated levels of circulating cytokines and immune-cell hyperactivation. Targeting cytokines during the management of COVID-19 patients has the potential to improve survival rates and reduce mortality. Although cytokine blockers and immune-host modulators are currently being tested in severely ill COVID-19 patients to cope with the overwhelming systemic inflammation, there is not too many successful cases, thus finding new cytokine blockers to attenuate the cytokine storm syndrome is meaningful. In this paper, we significantly attenuated the inflammatory responses induced by mouse hepatitis viruses A59 and SARS-CoV-2 through a soluble DR5-Fc (sDR5-Fc) chimeric protein that blocked the TNF-related apoptosis-inducing ligand-death receptor 5 (TRAIL-DR5) interaction. Our findings indicates that blocking the TRAIL-DR5 pathway through the sDR5-Fc chimeric protein is a promising strategy to treat COVID-19 severe patients requiring intensive care unit  admission or with chronic metabolic diseases.

Colonization of nasal cavities by Staphylococcus epidermidis mitigates SARS-CoV-2 nucleocapsid phosphoprotein-induced interleukin (IL)-6 in the lung.

Infection by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can trigger excessive interleukin (IL)-6 signalling, leading to a myriad of biological effects including a cytokine storm that contributes to multiple organ failure in severe coronavirus disease 2019 (COVID-19). Using a mouse model, we demonstrated that nasal inoculation of nucleocapsid phosphoprotein (NPP) of SARS-CoV-2 increased IL-6 content in bronchoalveolar lavage fluid (BALF). Nasal administration of liquid coco-caprylate/caprate (LCC) onto Staphylococcus epidermidis (S. epidermidis)-colonized mice significantly attenuated NPP-induced IL-6. Furthermore, S. epidermidis-mediated LCC fermentation to generate electricity and butyric acid that promoted bacterial colonization and activated free fatty acid receptor 2 (Ffar2) respectively. Inhibition of Ffar2 impeded the effect of S. epidermidis plus LCC on the reduction of NPP-induced IL-6. Collectively, these results suggest that nasal S. epidermidis is part of the first line of defence in ameliorating a cytokine storm induced by airway infection of SARS-CoV-2.

2-Deoxy-d-glucose induces deglycosylation of proinflammatory cytokine receptors and strongly reduces immunological responses in mouse models of inflammation.

Anti-proinflammatory cytokine therapies against interleukin (IL)-6, tumor necrosis factor (TNF)-α, and IL-1 are major advancements in treating inflammatory diseases, especially rheumatoid arthritis. Such therapies are mainly performed by injection of antibodies against cytokines or cytokine receptors. We initially found that the glycolytic inhibitor 2-deoxy-d-glucose (2-DG), a simple monosaccharide, attenuated cellular responses to IL-6 by inhibiting N-linked glycosylation of the IL-6 receptor gp130. Aglycoforms of gp130 did not bind to IL-6 or activate downstream intracellular signals that included Janus kinases. 2-DG completely inhibited dextran sodium sulfate-induced colitis, a mouse model for inflammatory bowel disease, and alleviated laminarin-induced arthritis in the SKG mouse, an experimental model for human rheumatoid arthritis. These diseases have been shown to be partially dependent on IL-6. We also found that 2-DG inhibited signals for other proinflammatory cytokines such as TNF-α, IL-1ß, and interferon -γ, and accordingly, prevented death by another inflammatory disease, lipopolysaccharide (LPS) shock. Furthermore, 2-DG prevented LPS shock, a model for a cytokine storm, and LPS-induced pulmonary inflammation, a model for acute respiratory distress syndrome of coronavirus disease 2019 (COVID-19). These results suggest that targeted therapies that inhibit cytokine receptor glycosylation are effective for treatment of various inflammatory diseases.

Ruxolitinib reduces severe CRS response by suspending CAR-T cell function instead of damaging CAR-T cells.

The therapeutic effect of CAR-T is often accompanied by sCRS, which is the main obstacle to the promotion of CAR-T therapy. The JAK1/2 inhibitor ruxolitinib has recently been confirmed as clinically effective in maintaining control over sCRS, however, its mechanism remains unclear. In this study, we firstly revealed that ruxolitinib significantly inhibited the proliferation of CAR-T cells without damaging viability, and induced an efficacy-favored differentiation phenotype. Second, ruxolitinib reduced the level of cytokine release not only from CAR-T cells, but also from other cells in the immune system. Third, the cytolytic activity of CAR-T cells was restored once the ruxolitinib was removed; however, the cytokines released from the CAR-T cells maintained an inhibited state to some degree. Finally, ruxolitinib significantly reduced the proliferation rate of CAR-T cells in vivo without affecting the therapeutic efficacy after withdrawal at the appropriate dose. We demonstrated pre-clinically that ruxolitinib interferes with both CAR-T cells and the other immune cells that play an important role in triggering sCRS reactions. This work provides useful and important scientific data for clinicians on the question of whether ruxolitinib has an effect on CAR-T cell function loss causing CAR-T treatment failure when applied in the treatment of sCRS, the answer to which is of great clinical significance.

IL-6/IFN-γ double knockdown CAR-T cells reduce the release of multiple cytokines from PBMCs in vitro.

CD19-targeted chimeric antigen receptor T (anti-CD19 CAR-T) cells have shown good therapeutic results in the treatment of CD19 + B cell acute lymphocytic leukemia and lymphoma. However, severe side reactions and cytotoxicity are great challenges in the application of anti-CD19 CAR-T cell therapy. Cytokine release syndrome (CRS) is the main side effect of CAR-T cell treatment, and interleukin-6 (IL-6) and interferon γ (IFN-γ) are cytokines that play major roles in CRS. Therefore, we investigated double knockdown (KD) of IL-6 and IFN-γ as a potential strategy to manage anti-CD19 CAR-T cell-associated CRS. These improved anti-CD19 CAR-T cells therapy retained the advantages of the original anti-CD19 CAR-T cells and additionally reduced the release of cytokines from CAR-T cells and other immune cells. Moreover, this study presented a novel approach to abrogate CRS through IL-6 and IFN-γ KD, which may potentially inhibit the release of multiple cytokines from CAR-T cells and peripheral blood mononuclear cells (PBMCs), a model of CRS correlate with in vivo features of the CAR-T therapy, thereby reducing the impact of CRS, improving the safety of CAR-T cell treatment, reducing toxicities, and maintaining the function of CAR-T cells.

Blocking TNF signaling may save lives in COVID-19 infection.

Global vaccination effort and better understanding of treatment strategies provided a ray of hope for improvement in COVID-19 pandemic, however, in many countries, the disease continues to collect its death toll. The major pathogenic mechanism behind severe cases associated with high mortality is the burst of pro-inflammatory cytokines TNF, IL-6, IFNγ and others, resulting in multiple organ failure. Although the exact contribution of each cytokine is not clear, we provide an evidence that the central mediator of cytokine storm and its devastating consequences may be TNF. This cytokine is known to be involved in activated blood clotting, lung damage, insulin resistance, heart failure, and other conditions. A number of currently available pharmaceutical agents such as monoclonal antibodies and soluble TNF receptors can effectively prevent TNF from binding to its receptor(s). Other drugs are known to block NFkB, the major signal transducer molecule used in TNF signaling, or to block kinases involved in downstream activation cascades. Some of these medicines have already been selected for clinical trials, but more work is needed. A simple, rapid, and inexpensive method of directly monitoring TNF levels may be a valuable tool for a timely selection of COVID-19 patients for anti-TNF therapy.

Treatment with soluble CD24 attenuates COVID-19-associated systemic immunopathology.

BACKGROUND: Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) causes coronavirus disease 2019 (COVID-19) through direct lysis of infected lung epithelial cells, which releases damage-associated molecular patterns and induces a pro-inflammatory cytokine milieu causing systemic inflammation. Anti-viral and anti-inflammatory agents have shown limited therapeutic efficacy. Soluble CD24 (CD24Fc) blunts the broad inflammatory response induced by damage-associated molecular patterns via binding to extracellular high mobility group box 1 and heat shock proteins, as well as regulating the downstream Siglec10-Src homology 2 domain-containing phosphatase 1 pathway. A recent randomized phase III trial evaluating CD24Fc for patients with severe COVID-19 (SAC-COVID; NCT04317040) demonstrated encouraging clinical efficacy. METHODS: Using a systems analytical approach, we studied peripheral blood samples obtained from patients enrolled at a single institution in the SAC-COVID trial to discern the impact of CD24Fc treatment on immune homeostasis. We performed high dimensional spectral flow cytometry and measured the levels of a broad array of cytokines and chemokines to discern the impact of CD24Fc treatment on immune homeostasis in patients with COVID-19. RESULTS: Twenty-two patients were enrolled, and the clinical characteristics from the CD24Fc vs. placebo groups were matched. Using high-content spectral flow cytometry and network-level analysis, we found that patients with severe COVID-19 had systemic hyper-activation of multiple cellular compartments, including CD8+ T cells, CD4+ T cells, and CD56+ natural killer cells. Treatment with CD24Fc blunted this systemic inflammation, inducing a return to homeostasis in NK and T cells without compromising the anti-Spike protein antibody response. CD24Fc significantly attenuated the systemic cytokine response and diminished the cytokine coexpression and network connectivity linked with COVID-19 severity and pathogenesis. CONCLUSIONS: Our data demonstrate that CD24Fc rapidly down-modulates systemic inflammation and restores immune homeostasis in SARS-CoV-2-infected individuals, supporting further development of CD24Fc as a novel therapeutic against severe COVID-19.

Monitoring and safety of CAR-T therapy in clinical practice.

INTRODUCTION: In the last few years, a new T cell therapy, chimeric antigen receptor-T (CAR-T) cells, has been developed. CAR-T cells are highly effective at inhibiting antitumor activity, but they can cause a wide spectrum of unusual side effects. AREAS COVERED: The present review provides an overview of the adverse events of CAR-T cell therapy, focusing on cytokine release syndrome, immune effector cell-associated neurotoxicity syndrome, increased risk of infections, and other long-term complications. Representative studies addressing the safety and efficacy of CAR-T cell therapy are summarized. EXPERT OPINION: In the coming years, we predict a great expansion in the use of CAR-T cell therapy with it applied to a higher number of patients with both malignant neoplasms and immune-mediated diseases. Despite physicians and patient expectations about the potential of this therapy, there are still several barriers that may limit providers' ability to supply quality care. This exciting and powerful new therapy requires the formation of new multidisciplinary teams to carry out a safe treatment administration and to successfully manage the resultant complications. The follow-up of these therapies is important for two aspects: effectiveness in different populations and real-life safety in short and in long-term follow-up.

Beneficial effects of novel aureobasidium pullulans strains produced beta-1,3-1,6 glucans on interleukin-6 and D-dimer levels in COVID-19 patients; results of a randomized multiple-arm pilot clinical study.

OBJECTIVE: In this pilot clinical study, we report the beneficial effects of beta glucans derived from two strains AFO-202 and N-163 of a black yeast Aureobasidium pullulans on the biomarkers for cytokine storm and coagulopathy in COVID-19 patients. METHODS: A total of 24 RT-PCR positive COVID-19 patients were recruited and randomly divided into three groups (Gr): Gr. 1 control (n = 8) - Standard treatment; Gr. 2: Standard treatment + AFO-202 beta glucan (n = 8); and Gr. 3, Standard treatment + combination of AFO-202 and N-163 beta glucans (n = 8) for 30 days. RESULTS: There was no mortality or requirement of ventilation of the subjects in any of the groups. There was a decrease in D-Dimer values (751 ng/ml to 143.89 ng/ml) and IL-6 values (7.395-3.16 pg/ml) in Gr. 1 in 15 days but the levels increased to abnormal levels on day 30 (D-Dimer: 202.5 ng/ml; IL-6 55.37 pg/ml); which steadily decreased up to day 30 in groups 2 (D-dimer: 560.99 ng/dl to 79.615; IL-6: 26.18-3.41 pg/ml) and 3 (D-dimer: 1614 ng/dl to 164.25 ng/dl; IL-6: 6.25-0.5 pg/ml). The same trend was observed with ESR. LCR and LeCR increased while NLR decreased significantly in Gr. 3. CD4 + and CD8 + T cell count showed relatively higher increase in Gr.3. There was no difference in CRP within the groups. CONCLUSION: As these beta glucans are well known food supplements with a track record for safety, larger multi-centric clinical studies are recommended to validate their use as an adjunct in the management of COVID-19 and the ensuing long COVID-19 syndrome.

Secretome of Mesenchymal Bone Marrow Stem Cells: Is It Immunosuppressive or Proinflammatory?

Mesenchymal stem cells (MSC) are characterized by tolerogenic potential and therefore, are used in the treatment of autoimmune diseases such as graft-versus-host disease (GVHD) reactions after allogeneic hematopoietic cell transplantation to improve the transplant functions, as well as for the therapy and prevention of cytokine storm in COVID-19 patients and some other conditions. However, MSC can exhibit proinflammatory activity, which causes risks for their clinical use. We studied the cytokine profile of bone marrow MSC culture and demonstrate intensive production of IL-6, IL-8, and chemokine MCP-1, which participate in the pathogenesis of cytokine storm and GVHD. At the same time, no anti-inflammatory IL-4 and IL-10 were detected. To reduce the risks of MSC application in the GVHD therapeutic protocols, further studies of the conditions promoting generation of MSC with tolerogenic potential and approved clinical standards of MSC use are required.

Mechanisms of cytokine release syndrome and neurotoxicity of CAR T-cell therapy and associated prevention and management strategies.

Chimeric antigen receptor (CAR) T-cell therapy has yielded impressive outcomes and transformed treatment algorithms for hematological malignancies. To date, five CAR T-cell products have been approved by the US Food and Drug Administration (FDA). Nevertheless, some significant toxicities pose great challenges to the development of CAR T-cell therapy, most notably cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS). Understanding the mechanisms underlying these toxicities and establishing prevention and treatment strategies are important. In this review, we summarize the mechanisms underlying CRS and ICANS and provide potential treatment and prevention strategies.

Genetic Modification of Cytokine Signaling to Enhance Efficacy of CAR T Cell Therapy in Solid Tumors.

Chimeric antigen receptor (CAR) T cell therapy has shown unprecedented success in treating advanced hematological malignancies. Its effectiveness in solid tumors has been limited due to heterogeneous antigen expression, a suppressive tumor microenvironment, suboptimal trafficking to the tumor site and poor CAR T cell persistence. Several approaches have been developed to overcome these obstacles through various strategies including the genetic engineering of CAR T cells to blunt the signaling of immune inhibitory receptors as well as to modulate signaling of cytokine/chemokine molecules and their receptors. In this review we offer our perspective on how genetically modifying cytokine/chemokine molecules and their receptors can improve CAR T cell qualities such as functionality, persistence (e.g. resistance to pro-apoptotic signals) and infiltration into tumor sites. Understanding how such modifications can overcome barriers to CAR T cell effectiveness will undoubtedly enhance the potential of CAR T cells against solid tumors.

Targeting folate receptor beta on monocytes/macrophages renders rapid inflammation resolution independent of root causes.

Provoked by sterile/nonsterile insults, prolonged monocyte mobilization and uncontrolled monocyte/macrophage activation can pose imminent or impending harm to the affected organs. Curiously, folate receptor beta (FRß), with subnanomolar affinity for the vitamin folic acid (FA), is upregulated during immune activation in hematopoietic cells of the myeloid lineage. This phenomenon has inspired a strong interest in exploring FRß-directed diagnostics/therapeutics. Previously, we have reported that FA-targeted aminopterin (AMT) therapy can modulate macrophage function and effectively treat animal models of inflammation. Our current investigation of a lead compound (EC2319) leads to discovery of a highly FR-specific mechanism of action independent of the root causes against inflammatory monocytes. We further show that EC2319 suppresses interleukin-6/interleukin-1ß release by FRß+ monocytes in a triple co-culture leukemic model of cytokine release syndrome with anti-CD19 chimeric antigen receptor T cells. Because of its chemical stability and metabolically activated linker, EC2319 demonstrates favorable pharmacokinetic characteristics and cross-species translatability to support future pre-clinical and clinical development.