Identification of Predictive Biomarkers for Cytokine Release Syndrome after Chimeric Antigen Receptor T-cell Therapy for Acute Lymphoblastic Leukemia

Acute myeloid leukemia chimeric antigen receptor T-cell immunotherapy: how far up the road have we traveled?

Chemotherapy resistance and relapse remain significant sources of mortality for children and adults with acute myeloid leukemia (AML). Further intensification of conventional cytotoxic chemotherapy is likely not feasible due to the severity of acute and long-term side effects upon normal tissues commonly induced by these drugs. Successful development and implementation of new precision medicine treatment approaches for patients with AML, which may improve leukemia remission and diminish toxicity, is thus a major priority. Tumor antigen-redirected chimeric antigen receptor (CAR) T-cell immunotherapies have induced remarkable responses in patients with relapsed or chemorefractory B-lymphoblastic leukemia, and similar strategies are now under early clinical study in adults with relapsed/refractory AML. However, potential on target/off tumor toxicity of AML CAR T-cell immunotherapies, notably aplasia of normal myeloid cells, may limit broader implementation of such approaches. Careful selection of optimal target antigens, consideration of toxicity mitigation strategies, and development of methodologies to circumvent potential CAR T-cell resistance are essential for successful implementation of cellular immunotherapies for patients with high-risk AML.

Application of chimeric antigen receptor-engineered T cells in ovarian cancer therapy

Due to the critical role of T cells in the immune surveillance of ovarian cancer, adoptive T-cell therapies are receiving increased attention as an immunotherapeutic approach for ovarian cancer. Chimeric antigen receptors (CARs), constructed by incorporating the single-chain Fv fragment to a T-cell signaling domain such as CD3 ζ or Fc receptor γ chain, endow T cell with nonmajor histocompatibility complex-restricted specificity. Dual specificity, trans-signaling CARs and affinity-tuned single-chain Fv fragment have broadened the applicability of CAR-engineered T-cell therapy and may be considered preferential to T cell receptor T-cell therapy in clinical care. As new insights into the CAR-engineered T cells have emerged over the last decade, we review the development of CAR T-cell therapy and discuss the progress and safety concerns regarding its translation from basic research into clinical care of ovarian cancer.

Novel Therapies for Acute Myeloid Leukemia: Are We Finally Breaking the Deadlock?

Acute myeloid leukemia (AML) is one of the best studied malignancies, and significant progress has been made in understanding the clinical implications of its disease biology. Unfortunately, drug development has not kept pace, as the '7+3' induction regimen remains the standard of care for patients fit for intensive therapy 40 years after its first use. Temporal improvements in overall survival were mostly confined to younger patients and driven by improvements in supportive care and use of hematopoietic stem cell transplantation. Multiple forms of novel therapy are currently in clinical trials and are attempting to bring bench discoveries to the bedside to benefit patients. These novel therapies include improved chemotherapeutic agents, targeted molecular inhibitors, cell cycle regulators, pro-apoptotic agents, epigenetic modifiers, and metabolic therapies. Immunotherapies in the form of vaccines; naked, conjugated and bispecific monoclonal antibodies; cell-based therapy; and immune checkpoint inhibitors are also being evaluated in an effort to replicate the success seen in other malignancies. Herein, we review the scientific basis of these novel therapeutic approaches, summarize the currently available evidence, and look into the future of AML therapy by highlighting key clinical studies and the challenges the field continues to face.

Interleukin-6: designing specific therapeutics for a complex cytokine

Interleukin-6 (IL-6) is a pivotal cytokine with a diverse repertoire of physiological functions that include regulation of immune cell proliferation and differentiation. Dysregulation of IL-6 signalling is associated with inflammatory and lymphoproliferative disorders such as rheumatoid arthritis and Castleman disease, and several classes of therapeutics have been developed that target components of the IL-6 signalling pathway. So far, monoclonal antibodies against IL-6 or IL-6 receptor (IL-6R) and Janus kinases (JAK) inhibitors have been successfully developed for the treatment of autoimmune diseases such as rheumatoid arthritis. However, clinical trials of agents targeting IL-6 signalling have also raised questions about the diseases and patient populations for which such agents have an appropriate benefit-risk profile. Knowledge from clinical trials and advances in our understanding of the complexities of IL-6 signalling, including the potential to target an IL-6 trans-signalling pathway, are now indicating novel opportunities for therapeutic intervention. In this Review, we overview the roles of IL-6 in health and disease and analyse progress with several approaches of inhibiting IL-6-signalling, with the aim of illuminating when and how to apply IL-6 blockade.

The use of chimeric antigen receptor T cells in patients with non-Hodgkin lymphoma

Resistance to conventional lines of therapy develops in approximately 20% of all patients with lymphoma. These patients have a dismal prognosis, with an expected median survival of 6.3 months. In recent years, T-cell immunotherapy has demonstrated a remarkable capacity to induce complete and durable clinical responses in patients with chemotherapy-refractory lymphoma. A major contributor to the success of immunotherapy has been the advent of genetic engineering technologies that introduce a chimeric antigen receptor (CAR) into T cells to focus their killing activity on tumor cells. The adoptive transfer of autologous CAR T-cell products specific for the pan-B-cell antigen CD19 have now received approval from the US Food and Drug Administration (FDA) for the treatment of relapsed or chemotherapy-resistant B-cell non-Hodgkin lymphoma. This review is designed to showcase the clinical efficacy and unique toxicities of individually developed CAR T-cell products for the treatment of lymphomas and their evolution from the laboratory bench to commercialization.

Peripheral Blood Grafts for T Cell-Replete Haploidentical Transplantation Increase the Incidence and Severity of Cytokine Release Syndrome

T cell-replete post-transplant cyclophosphamide (PTCy)-based protocols have led to increasing use of haploidentical allogeneic hematopoietic cell transplantation (haploHCT). With this approach, bidirectional alloreactivity causing nonengraftment or severe graft-versus-host disease (GVHD) is no a longer major barrier to haploHCT. PTCy eliminates alloreactive lymphocytes but spares CD34⁺ stem cells and regulatory T lymphocytes, resulting in reliable hematopoietic recovery with relatively low incidence of GVHD. The immediate post-haploHCT course, usually before PTCy administration, is often complicated by cytokine release syndrome (CRS). The predictors of CRS and its effect on outcomes post-transplant have not been fully ascertained. We analyzed the outcomes of 66 patients who received haploHCT at our institution. Using published CRS criteria we identified 48 patients who developed CRS. In multivariate analysis peripheral blood grafts were significantly associated with grade ≥ 2 CRS, compared with bone marrow. Grade ≥ 2 CRS (compared with grade < 2) was not associated with differences in overall survival or nonrelapse mortality. Severe CRS was associated with a statistically nonsignificant trend toward higher incidences of grades III to IV acute GVHD, especially in the context of peripheral blood grafts. CRS is a common complication after T cell-replete peripheral blood haploHCT, but post-transplant survival outcomes may not be affected in those with severe CRS.

A single dose of peripherally infused EGFRvIII-directed CAR T cells mediates antigen loss and induces adaptive resistance in patients with recurrent glioblastoma

We conducted a first-in-human study of intravenous delivery of a single dose of autologous T cells redirected to the epidermal growth factor receptor variant III (EGFRvIII) mutation by a chimeric antigen receptor (CAR). We report our findings on the first 10 recurrent glioblastoma (GBM) patients treated. We found that manufacturing and infusion of CAR-modified T cell (CART)-EGFRvIII cells are feasible and safe, without evidence of off-tumor toxicity or cytokine release syndrome. One patient has had residual stable disease for over 18 months of follow-up. All patients demonstrated detectable transient expansion of CART-EGFRvIII cells in peripheral blood. Seven patients had post-CART-EGFRvIII surgical intervention, which allowed for tissue-specific analysis of CART-EGFRvIII trafficking to the tumor, phenotyping of tumor-infiltrating T cells and the tumor microenvironment in situ, and analysis of post-therapy EGFRvIII target antigen expression. Imaging findings after CART immunotherapy were complex to interpret, further reinforcing the need for pathologic sampling in infused patients. We found trafficking of CART-EGFRvIII cells to regions of active GBM, with antigen decrease in five of these seven patients. In situ evaluation of the tumor environment demonstrated increased and robust expression of inhibitory molecules and infiltration by regulatory T cells after CART-EGFRvIII infusion, compared to pre-CART-EGFRvIII infusion tumor specimens. Our initial experience with CAR T cells in recurrent GBM suggests that although intravenous infusion results in on-target activity in the brain, overcoming the adaptive changes in the local tumor microenvironment and addressing the antigen heterogeneity may improve the efficacy of EGFRvIII-directed strategies in GBM.

FDA Approval Summary: Tocilizumab for Treatment of Chimeric Antigen Receptor T Cell-Induced Severe or Life-Threatening Cytokine Release Syndrome

This article summarizes key review findings that supported the approval of tocilizumab for treatment of severe or life‐threatening CAR T cell‐induced cytokine release syndrome.

On August 30, 2017, the U.S. Food and Drug Administration approved Actemra (tocilizumab, Genentech, Inc., South San Francisco, CA) for the treatment of severe or life‐threatening chimeric antigen receptor (CAR) T cell‐induced cytokine release syndrome (CRS) in adults and in pediatric patients 2 years of age and older. The approval was based on a retrospective analysis of data for patients who developed CRS after treatment with CTL019 and KTE‐C19 on prospective clinical trials. Evaluable patients had been treated with intravenous tocilizumab 8 mg/kg (12 mg/kg for patients <30 kg) for severe or life‐threatening CRS; only the first episode of CRS was included in the analysis. The efficacy population for the CTL019 cohort included 24 male and 21 female patients (total 45 patients) of median age 12 years. The median time from the start of CRS to the first dose of tocilizumab was 4 days (range, 0–18 days). Patients were considered responders if CRS resolved within 14 days of the first dose of tocilizumab, if no more than 2 doses of tocilizumab were needed, and if no drugs other than tocilizumab and corticosteroids were used for treatment. Thirty‐one patients (69%; 95% confidence interval, 53%–82%) achieved a response as defined. In an independent cohort of 15 patients with KTE‐C19‐induced CRS, 53% responded. Further study is needed to determine the optimal dose of tocilizumab and to confirm the safety of its use for treatment of patients with CAR T cell‐induced CRS.

Implications for Practice.

Severe or life‐threatening chimeric antigen receptor (CAR) T cell‐induced cytokine release syndrome (CRS) requires urgent treatment to prevent fatal outcomes. In two independent cohorts, the majority of patients with severe or life‐threatening CAR T cell‐induced CRS responded to treatment with one or two doses of tocilizumab in addition to advanced supportive care. More research is needed to determine the optimal dose and schedule of tocilizumab for treatment of CAR T cell‐induced CRS.

Genetically enhanced T lymphocytes and the intensive care unit

Chimeric antigen receptor-modified T cells (CAR-T cells) and donor lymphocyte infusion (DLI) are important protocols in lymphocyte engineering. CAR-T cells have emerged as a new modality for cancer immunotherapy due to their potential efficacy against hematological malignancies. These genetically modified receptors contain an antigen-binding moiety, a hinge region, a transmembrane domain, and an intracellular costimulatory domain resulting in lymphocyte T cell activation subsequent to antigen binding. In present-day medicine, four generations of CAR-T cells are described depending on the intracellular signaling domain number of T cell receptors. DLI represents a form of adoptive therapy used after hematopoietic stem cell transplant for its anti-tumor and anti-infectious properties. This article covers the current status of CAR-T cells and DLI research in the intensive care unit (ICU) patient, including the efficacy, toxicity, side effects and treatment.

Immunotherapy for Hepatocellular Carcinoma: Current Advances and Future Expectations

Primary liver cancer is a common kind of digestive cancers with high malignancy, causing 745,500 deaths each year. Hepatocellular carcinoma is the major pathological type of primary liver cancer. Traditional treatment methods for patients with hepatocellular carcinoma have shown poor efficacy in killing residual cancer cells for a long time. In recent years, tumor immunotherapy has emerged as a promising method owing to its safety and efficacy with respect to delaying the progression of advanced tumors and protecting postoperative patients against tumor relapse and metastasis. Immune tolerance and suppression in tumor microenvironments are the theoretical basis of immunotherapy. Adoptive cell therapy functions by stimulating and cultivating autologous lymphocytes ex vivo and then reinfusing them into the patient to kill cancer cells. Cancer vaccination is performed using antigenic substances to activate tumor-specific immune responses. Immune checkpoint inhibitors can reactivate tumor-specific T cells and develop an antitumor effect by suppressing checkpoint-mediated signaling. Oncolytic viruses may selectively replicate in tumor cells and cause lysis without harming normal tissues. Here, we briefly introduce the mechanism of immunosuppression in hepatocellular carcinoma and summarize the rationale of the four major immunotherapeutic approaches with their current advances.

Extracellular NGFR Spacers Allow Efficient Tracking and Enrichment of Fully Functional CAR-T Cells Co-Expressing a Suicide Gene

Chimeric antigen receptor (CAR)-T cell immunotherapy is at the forefront of innovative cancer therapeutics. However, lack of standardization of cellular products within the same clinical trial and lack of harmonization between different trials have hindered the clear identification of efficacy and safety determinants that should be unveiled in order to advance the field. With the aim of facilitating the isolation and in vivo tracking of CAR-T cells, we here propose the inclusion within the CAR molecule of a novel extracellular spacer based on the low-affinity nerve-growth-factor receptor (NGFR). We screened four different spacer designs using as target antigen the CD44 isoform variant 6 (CD44v6). We successfully generated NGFR-spaced CD44v6 CAR-T cells that could be efficiently enriched with clinical-grade immuno-magnetic beads without negative consequences on subsequent expansion, immuno-phenotype, in vitro antitumor reactivity, and conditional ablation when co-expressing a suicide gene. Most importantly, these cells could be tracked with anti-NGFR monoclonal antibodies in NSG mice, where they expanded, persisted, and exerted potent antitumor effects against both high leukemia and myeloma burdens. Similar results were obtained with NGFR-enriched CAR-T cells specific for CD19 or CEA, suggesting the universality of this strategy. In conclusion, we have demonstrated that the incorporation of the NGFR marker gene within the CAR sequence allows for a single molecule to simultaneously work as a therapeutic and selection/tracking gene. Looking ahead, NGFR spacer enrichment might allow good manufacturing procedures-manufacturing of standardized CAR-T cell products with high therapeutic potential, which could be harmonized in different clinical trials and used in combination with a suicide gene for future application in the allogeneic setting.

The Pharmacology of T Cell Therapies

Adoptive cellular therapy using T cells with tumor specificity derived from either natural T cell receptors (TCRs) or an artificial chimeric antigen receptor (CAR) has reached late phase clinical testing, with two CAR T cell therapies achieving regulatory approval within the United States in 2017. The effective use of these therapies depends upon an understanding of their pharmacology, which is quite divergent from traditional small molecule or biologic drugs. We review the different types of T cell therapy under clinical development, the factors affecting cellular kinetics following infusion, and the relationship between these cellular kinetics and anti-cancer activity. We also discuss the toxicity associated with T cell therapies, with an emphasis on cytokine release syndrome and neurotoxicity, and the gaps in knowledge regarding these frequent and unique adverse effects.

Grading of cytokine release syndrome associated with the CAR T cell therapy tisagenlecleucel

BACKGROUND

Anti-CD19 CAR T cell therapy has demonstrated high response rates in patients with relapsed or refractory (r/r) B cell malignancies but is associated with significant toxicity. Cytokine release syndrome (CRS) is the most significant complication associated with CAR T cell therapy, and it is critical to have a reproducible and easy method to grade CRS after CAR T cell infusions.

DISCUSSION

The Common Terminology Criteria for Adverse Events scale is inadequate for grading CRS associated with cellular therapy. Clinical experience with the anti-CD19 CAR T cell therapy tisagenlecleucel at the University of Pennsylvania (Penn) was used to develop the Penn grading scale for CRS. The Penn grading scale depends on easily accessible clinical features; does not rely on location of care or quantitation of supportive care; assigns grades to guide CRS management; distinguishes between mild, moderate, severe, and life-threatening CRS; and applies to both early-onset and delayed-onset CRS associated with T cell therapies. Clinical data from 55 pediatric patients with r/r B cell acute lymphoblastic leukemia and 42 patients with r/r chronic lymphocytic lymphoma treated with tisagenlecleucel were used to demonstrate the current application of the Penn grading scale.

CONCLUSION

We show that the Penn grading scale provides reproducible CRS grading that can be useful to guide therapy and that can be applied across clinical trials and treatment platforms.

Reprint of: Building a Safer and Faster CAR: Seatbelts, Airbags, and CRISPR

Therapeutic T cell engineering has recently garnered widespread interest because of the success of CD19 chimeric antigen receptor (CAR) therapy. CARs are synthetic receptors for antigen that redirect the specificity and reprogram the function of the T cells in which they are genetically introduced. CARs targeting CD19, a cell surface molecule found in most leukemias and lymphomas, have yielded high remission rates in patients with chemorefractory, relapsed disease, including acute lymphoblastic leukemia, chronic lymphocytic leukemia, and non-Hodgkin lymphoma. The toxicities of this treatment include B cell aplasia, cytokine release syndrome (CRS), and neurotoxicity. Although reversible in most instances, these toxicities may require specific medical interventions, including transfer to intensive care to treat severe CRS. Guidelines for managing these toxicities are emerging. The recent report of a nonhuman primate model for CRS is poised to help advance the management of this syndrome. Finally, new engineering modalities, based on the use of targeted nucleases like CRISPR, may further enhance the efficacy and safety of CAR T cells.

Chimeric Antigen Receptor T-Cells for the Treatment of B-Cell Acute Lymphoblastic Leukemia

Chimeric antigen receptor (CAR) T-cell technology has seen a rapid development over the last decade mostly due to the potential that these cells may have in treating malignant diseases. It is a generally accepted principle that very few therapeutic compounds deliver a clinical response without treatment-related toxicity, and studies have shown that CAR T-cells are not an exception to this rule. While large multinational drug companies are currently investigating the potential role of CAR T-cells in hematological oncology, the potential of such cellular therapies are being recognized worldwide as they are expected to expand in the patient to support the establishment of the immune memory, provide a continuous surveillance to prevent and/or treat a relapse, and keep the targeted malignant cell subpopulation in check. In this article, we present the possible advantages of using CAR T-cells in treating acute lymphoblastic leukemia, presenting the technology and the current knowledge in their preclinical and early clinical trial use. Thus, this article first presents the main present-day knowledge on the standard of care for acute lymphoblastic leukemia. Afterward, current knowledge is presented about the use of CAR T-cells in cancer immunotherapy, describing their design, the molecular constructs, and the preclinical data on murine models to properly explain the background for their clinical use. Last, but certainly not least, this article presents the use of CAR T-cells for the immunotherapy of B-cell acute lymphoblastic leukemia, describing both their potential clinical advantages and the possible side effects.

Engineering chimeric antigen receptor-T cells for cancer treatment

Intratumor heterogeneity of tumor clones and an immunosuppressive microenvironment in cancer ecosystems contribute to inherent difficulties for tumor treatment. Recently, chimeric antigen receptor (CAR) T-cell therapy has been successfully applied in the treatment of B-cell malignancies, underscoring its great potential in antitumor therapy. However, functional challenges of CAR-T cell therapy, especially in solid tumors, remain. Here, we describe cancer-immunity phenotypes from a clonal-stromal-immune perspective and elucidate mechanisms of T-cell exhaustion that contribute to tumor immune evasion. Then we assess the functional challenges of CAR-T cell therapy, including cell trafficking and infiltration, targeted-recognition and killing of tumor cells, T-cell proliferation and persistence, immunosuppressive microenvironment and self-control regulation. Finally, we delineate tumor precision informatics and advancements in engineered CAR-T cells to counteract inherent challenges of the CAR-T cell therapy, either alone or in combination with traditional therapeutics, and highlight the therapeutic potential of this approach in future tumor precision treatment.

New developments in immunotherapy for pediatric leukemia

PURPOSE OF REVIEW

Immunotherapy for the treatment of cancer has advanced at a tremendous pace over the last decade. In this review, we provide an overview of recent progress in immunotherapy for the treatment of leukemia, focusing on antibody-drug conjugates (ADC), bi-specific T-cell engagers (BiTE), and chimeric antigen receptor (CAR) T cells.

RECENT FINDINGS

Ongoing clinical trials of CAR T cells directed against CD19 have produced complete remission rates as high as 93%, prompting global multicenter phase 2 trials and the first FDA approval of a CAR T-cell therapy. Insights into cytokine release syndrome, a toxicity of CAR T-cell therapy, and the cause for relapse after CAR T-cell therapy are evolving. The bispecific antibody blinatumomab and the ADCs inotuzumab and gemtuzumab have also recently received FDA approval for ALL and AML, respectively, moving these agents into a more prominent role in the relapse setting.

SUMMARY

The use of immunotherapy for leukemia has been successful in creating durable remissions for multiply relapsed and refractory patients who previously had little chance of cure. The ongoing clinical and preclinical work continues to advance our understanding of these immune-based therapies, and will shape the next generation of clinical trials.

T-cell Immunotherapies and the Role of Nonclinical Assessment: The Balance between Efficacy and Pathology

Gene-engineered T-cell therapies have the potential to revolutionize the treatment of cancer. These therapies have shown exceptional clinical efficacy specifically in the field of B-cell malignancies and the first products (Kymriah™ and Yescarta™) have recently been approved in the United States for specific indications. The power of these treatments is also linked with a distinct set of toxicities both predicted and unpredicted, including off-tumor activity, cytokine release syndromes, and neurotoxicity, occasionally with fatal consequences. As these therapies begin to reach more patients, it is critical to develop the nonclinical tools to adequately determine the mechanisms driving these toxicities, to assess the safety risks of candidate products, and to develop strategies for safety management.

Pleural cavity cytokine release syndrome in CD19-directed chimeric antigen receptor-modified T cell therapy: A case report

RATIONALE

Cytokine release syndrome (CRS) is a common and potentially fatal complication of CAR-T cell therapy. However, compartment CRS is relatively rare in hematological malignancies, as well as in solid tumors. The pathogenesis and prognosis of compartment CRS are unclear and there is no standardized treatment yet. In this case report, we will introduce a patient developing pleural cavity CRS after CART19s infusion.

PATIENT CONCERNS

A 28-year-old woman was admitted for evaluation of mediastinal mass. Her relevant examinations were comoleted.

DIAGNOSES

She was diagnosed as diffuse large B cell lymphoma (DLBCL, non-GCB type).

INTERVENTIONS

She received chemotherapies including 1 cycle of R-DAEPORCH, 1 cycle of R-CHOPE, 2 cycles of R-CHOP, and 4 cycles of R-GDP during the disease course.

OUTCOMES

The cytokine levels of hydrothorax were considerably high when serum cytokines were within normal range, with IL-6 at 1212.45 versus 5.69 pg/mL. qPCR analysis for CAR constructs showed 1,119,696 copies/μg DNA in hydrothorax and 522,227 copies/μg DNA in blood.

LESSONS

The results indicated that CART19 cells trafficked to the pleural cavity and interacted with the CD19-positive lymphoma cells directly, causing cytokine release in situ.

Biomarkers of cytokine release syndrome and neurotoxicity related to CAR-T cell therapy

Severe cytokine release syndrome (CRS) and neurotoxicity following chimeric antigen receptor T cell (CAR-T) therapy can be life-threatening in some cases, and management of those toxicities is still a great challenge for physicians. Researchers hope to understand the pathophysiology of CRS and neurotoxicity, and identify predictive biomarkers that can forecast those toxicities in advance. Some risk factors for severe CRS and/or neurotoxicity including patient and treatment characteristics have been identified in multiple clinical trials of CAR-T cell therapy. Moreover, several groups have identified some predictive biomarkers that are able to determine beforehand which patients may suffer severe CRS and/or neurotoxicity during CAR-T cell therapy, facilitating testing of early intervention strategies for those toxicities. However, further studies are needed to better understand the biology and related risk factors for CRS and/or neurotoxicity, and determine if those identified predictors can be extrapolated to other series. Herein, we review the pathophysiology of CRS and neurotoxicity, and summarize the progress of predictive biomarkers to improve CAR-T cell therapy in cancer.

TEM8/ANTXR1-Specific CAR T Cells as a Targeted Therapy for Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) is an aggressive disease lacking targeted therapy. In this study, we developed a CAR T cell-based immunotherapeutic strategy to target TEM8, a marker initially defined on endothelial cells in colon tumors that was discovered recently to be upregulated in TNBC. CAR T cells were developed that upon specific recognition of TEM8 secreted immunostimulatory cytokines and killed tumor endothelial cells as well as TEM8-positive TNBC cells. Notably, the TEM8 CAR T cells targeted breast cancer stem-like cells, offsetting the formation of mammospheres relative to nontransduced T cells. Adoptive transfer of TEM8 CAR T cells induced regression of established, localized patient-derived xenograft tumors, as well as lung metastatic TNBC cell line-derived xenograft tumors, by both killing TEM8+ TNBC tumor cells and targeting the tumor endothelium to block tumor neovascularization. Our findings offer a preclinical proof of concept for immunotherapeutic targeting of TEM8 as a strategy to treat TNBC.Significance: These findings offer a preclinical proof of concept for immunotherapeutic targeting of an endothelial antigen that is overexpressed in triple-negative breast cancer and the associated tumor vasculature. Cancer Res; 78(2); 489-500. ©2017 AACR.

Enhancing CAR T cell persistence through ICOS and 4-1BB costimulation

Successful tumor eradication by chimeric antigen receptor-expressing (CAR-expressing) T lymphocytes depends on CAR T cell persistence and effector function. We hypothesized that CD4+ and CD8+ T cells may exhibit distinct persistence and effector phenotypes, depending on the identity of specific intracellular signaling domains (ICDs) used to generate the CAR. First, we demonstrate that the ICOS ICD dramatically enhanced the in vivo persistence of CAR-expressing CD4+ T cells that, in turn, increased the persistence of CD8+ T cells expressing either CD28- or 4-1BB-based CARs. These data indicate that persistence of CD8+ T cells was highly dependent on a helper effect provided by the ICD used to redirect CD4+ T cells. Second, we discovered that combining ICOS and 4-1BB ICDs in a third-generation CAR displayed superior antitumor effects and increased persistence in vivo. Interestingly, we found that the membrane-proximal ICD displayed a dominant effect over the distal domain in third-generation CARs. The optimal antitumor and persistence benefits observed in third-generation ICOSBBz CAR T cells required the ICOS ICD to be positioned proximal to the cell membrane and linked to the ICOS transmembrane domain. Thus, CARs with ICOS and 4-1BB ICD demonstrate increased efficacy in solid tumor models over our current 4-1BB-based CAR and are promising therapeutics for clinical testing.

The confused oncologic patient: a rational clinical approach

PURPOSE OF REVIEW

The purpose of this review is to provide a practical clinical approach to confusion in the patient with cancer. Confusion in the cancer population has a broader differential diagnosis than in the general medical population. The clinician must consider the usual differential diagnoses as well as causes unique to the cancer patient including direct complications from the cancer and indirect complications related to cancer treatment.

RECENT FINDINGS

In the recent age of precision medicine, the oncologist now utilizes the genomic profile of both the patient and the tumor to provide advanced biologic therapies including targeted anticancer drugs, antiangiogenic agents, and immunotherapy. Such advances carry with them an emerging pattern of neurotoxicity which, although less well described in the literature, is now an important consideration to the clinical approach to confusion in cancer patients.

SUMMARY

Confusion is the most common neurologic complication in cancer and is associated with significant morbidity, mortality, and prolonged hospital stays resulting in increased healthcare costs. Early recognition and treatment of delirium is essential to improve clinical outcomes.

B cells as biomarkers: predicting immune checkpoint therapy adverse events

Immune checkpoint inhibitors are becoming a cornerstone of cancer immunotherapy as a result of their clinical success in relieving immune suppression and driving durable antitumor T cell responses in certain subsets of patients. Unfortunately, checkpoint inhibition is also associated with treatment-related toxicities that result in a myriad of side effects, ranging from mild and manageable to severe and debilitating. In this issue of the JCI, Das and colleagues report an association between early therapy-induced changes in circulating B cells and an increased risk of high-grade immune-related adverse events (IRAEs) in patients treated with checkpoint inhibitors that target cytotoxic T lymphocyte-associated antigen-4 (CTLA4) and programmed cell death protein 1 (PD1). These findings identify potential predictive biomarkers for high-grade IRAEs that may be leveraged to improve patient monitoring and may prompt new treatment strategies to prevent IRAEs.

Redirecting T cells to hematological malignancies with bispecific antibodies

There is a need to improve outcomes for patients with recurrent and/or refractory hematological malignancies. Immunotherapy holds the promise to meet this need, because it does not rely on the cytotoxic mechanism of conventional therapies. Among different forms of immunotherapy, redirecting T cells to hematological malignancies with bispecific antibodies (BsAbs) is an attractive strategy. BsAbs are an "off-the-shelf" product that is easily scalable in contrast to adoptive T-cell therapies. Among these, the bispecific T-cell engager blinatumomab has emerged as the most successful BsAb to date. It consists of 2 single-chain variable fragments specific for CD19 present on B-cell malignancies and CD3 expressed on almost all T cells. Blinatumomab has shown potent antitumor activity as a single agent, particularly for acute lymphoblastic leukemia, resulting in its US Food and Drug Administration approval. However, although successful in inducing remissions, these are normally short-lived, with median response durations of <1 year. Nevertheless, the success of blinatumomab has reinvigorated the BsAb field, which is bustling with preclinical and clinical studies for not only B-cell-derived lymphoblastic leukemia and lymphoma but also acute myeloid leukemia and multiple myeloma. Here, we will review the successes and challenges of T-cell-targeted BsAbs for the immunotherapy of hematological malignancies with special focus on conducted clinical studies and strategies to improve their efficacy.

Building a Safer and Faster CAR: Seatbelts, Airbags, and CRISPR

Therapeutic T cell engineering has recently garnered widespread interest because of the success of CD19 chimeric antigen receptor (CAR) therapy. CARs are synthetic receptors for antigen that redirect the specificity and reprogram the function of the T cells in which they are genetically introduced. CARs targeting CD19, a cell surface molecule found in most leukemias and lymphomas, have yielded high remission rates in patients with chemorefractory, relapsed disease, including acute lymphoblastic leukemia, chronic lymphocytic leukemia, and non-Hodgkin lymphoma. The toxicities of this treatment include B cell aplasia, cytokine release syndrome (CRS), and neurotoxicity. Although reversible in most instances, these toxicities may require specific medical interventions, including transfer to intensive care to treat severe CRS. Guidelines for managing these toxicities are emerging. The recent report of a nonhuman primate model for CRS is poised to help advance the management of this syndrome. Finally, new engineering modalities, based on the use of targeted nucleases like CRISPR, may further enhance the efficacy and safety of CAR T cells.

Tisagenlecleucel: The First CAR on the Highway to Remission for Acute Lymphoblastic Leukemia

Tisagenlecleucel is a first-in-class chimeric antigen receptor (CAR) T-cell therapy approved by the US Food and Drug Administration in 2017 for relapsed/refractory (RR) acute lymphoblastic leukemia (ALL) in patients up to 25 years of age. Tisagenlecleucel is an autologous T-cell therapy that is genetically engineered with a lentiviral vector to seek and eliminate CD19-expressing B cells throughout the patient's body and retain antitumor immune surveillance following remission. This groundbreaking cellular therapy brings unprecedented single-agent efficacy to patients with RR ALL, citing complete response rates of greater than 80% and 6-month relapse-free survivals exceeding 60% in a patient population with poor prognosis and few treatment options. Patients receiving CAR T-cell therapy are at risk for cytokine release syndrome (CRS), neurotoxicity, and infections, along with other toxicities that may be severe or life-threatening. The cornerstone of the management of moderate to severe CRS is treatment with the interleukin-6 antagonist tocilizumab, with dramatic responses often occurring within 24 hours. The optimal management of neurotoxicity following tisagenlecleucel remains undefined. It is critical that providers caring for patients receiving tisagenlecleucel understand the multistep process to prepare a patient for therapy, how to closely monitor patients for toxicity, and how to manage emergent adverse events following cell infusion.

Axicabtagene Ciloleucel CAR T-Cell Therapy in Refractory Large B-Cell Lymphoma

BACKGROUND

In a phase 1 trial, axicabtagene ciloleucel (axi-cel), an autologous anti-CD19 chimeric antigen receptor (CAR) T-cell therapy, showed efficacy in patients with refractory large B-cell lymphoma after the failure of conventional therapy.

METHODS

In this multicenter, phase 2 trial, we enrolled 111 patients with diffuse large B-cell lymphoma, primary mediastinal B-cell lymphoma, or transformed follicular lymphoma who had refractory disease despite undergoing recommended prior therapy. Patients received a target dose of 2×106 anti-CD19 CAR T cells per kilogram of body weight after receiving a conditioning regimen of low-dose cyclophosphamide and fludarabine. The primary end point was the rate of objective response (calculated as the combined rates of complete response and partial response). Secondary end points included overall survival, safety, and biomarker assessments.

RESULTS

Among the 111 patients who were enrolled, axi-cel was successfully manufactured for 110 (99%) and administered to 101 (91%). The objective response rate was 82%, and the complete response rate was 54%.With a median follow-up of 15.4 months, 42% of the patients continued to have a response, with 40% continuing to have a complete response. The overall rate of survival at 18 months was 52%. The most common adverse events of grade 3 or higher during treatment were neutropenia (in 78% of the patients), anemia (in 43%), and thrombocytopenia (in 38%). Grade 3 or higher cytokine release syndrome and neurologic events occurred in 13% and 28% of the patients, respectively. Three of the patients died during treatment. Higher CAR T-cell levels in blood were associated with response.

CONCLUSIONS

In this multicenter study, patients with refractory large B-cell lymphoma who received CAR T-cell therapy with axi-cel had high levels of durable response, with a safety profile that included myelosuppression, the cytokine release syndrome, and neurologic events. (Funded by Kite Pharma and the Leukemia and Lymphoma Society Therapy Acceleration Program; ZUMA-1 ClinicalTrials.gov number, NCT02348216 .).

The Evolution and Future of CAR T Cells for B-Cell Acute Lymphoblastic Leukemia

Several CAR T designs with CD19 specificity have been associated with consistent responses in clinical trials with complete remission (CR) rates ranging from 70-90%. Relevant challenges remain to be addressed, such as production time, early loss of CAR T cells, relapse due to loss of the target antigen, and prevention of severe cytokine release syndrome and neurotoxicity. This review describes constructs, clinical trial results, side effects, and future direction of CAR T-cell therapy in B-ALL.

Severe cytokine release syndrome in a patient receiving PD-1-directed therapy

Cytokine release syndrome (CRS) is a phenomenon of immune hyperactivation described in the setting of cellular and bispecific T-cell engaging immunotherapy. Checkpoint blockade using anti-programmed cell death 1 (anti-PD-1) inhibitors is an approach to antitumor immune system stimulation. A 29-year-old female with alveolar soft part sarcoma developed severe CRS after treatment with anti-PD-1 therapy. CRS was characterized by high fevers, encephalopathy, hypotension, hypoxia, hepatic dysfunction, and evidence of coagulopathy, and resolved after infusion of the interleukin-6 inhibitor tocilizumab and corticosteroids.

Safety and Efficacy of Intratumoral Injections of Chimeric Antigen Receptor (CAR) T Cells in Metastatic Breast Cancer

Chimeric antigen receptors (CAR) are synthetic molecules that provide new specificities to T cells. Although successful in treatment of hematologic malignancies, CAR T cells are ineffective for solid tumors to date. We found that the cell-surface molecule c-Met was expressed in ∼50% of breast tumors, prompting the construction of a CAR T cell specific for c-Met, which halted tumor growth in immune-incompetent mice with tumor xenografts. We then evaluated the safety and feasibility of treating metastatic breast cancer with intratumoral administration of mRNA-transfected c-Met-CAR T cells in a phase 0 clinical trial (NCT01837602). Introducing the CAR construct via mRNA ensured safety by limiting the nontumor cell effects (on-target/off-tumor) of targeting c-Met. Patients with metastatic breast cancer with accessible cutaneous or lymph node metastases received a single intratumoral injection of 3 × 10⁷ or 3 × 10⁸ cells. CAR T mRNA was detectable in peripheral blood and in the injected tumor tissues after intratumoral injection in 2 and 4 patients, respectively. mRNA c-Met-CAR T cell injections were well tolerated, as none of the patients had study drug-related adverse effects greater than grade 1. Tumors treated with intratumoral injected mRNA c-Met-CAR T cells were excised and analyzed by immunohistochemistry, revealing extensive tumor necrosis at the injection site, cellular debris, loss of c-Met immunoreactivity, all surrounded by macrophages at the leading edges and within necrotic zones. We conclude that intratumoral injections of mRNA c-Met-CAR T cells are well tolerated and evoke an inflammatory response within tumors. Cancer Immunol Res; 5(12); 1152-61. ©2017 AACR.

CAR-T Cells: A Systematic Review and Mixed Methods Analysis of the Clinical Trial Landscape

CAR-T cells are a promising new therapy that offer significant advantages compared with conventional immunotherapies. This systematic review and clinical trial landscape identifies and critiques published CAR-T cell clinical trials and examines the critical factors required to enable CAR-T cells to become a standard therapy. A review of the literature was conducted to identify suitable studies from the MEDLINE and Ovid bibliographic databases. The literature and database searches identified 20 studies for inclusion. The average number of participants per clinical trial examined was 11 patients. All studies included in this systematic review investigated CAR-T cells and were prospective, uncontrolled clinical studies. Leukemia is the most common cancer subtype and accounts for 57.4% (n = 120) of disease indications. The majority of studies used an autologous cell source (85%, n = 17) rather than an allogeneic cell source. Translational challenges encompass technical considerations relating to CAR-T cell development, manufacturing practicability, clinical trial approaches, CAR-T cell quality and persistence, and patient management.

[Progress in clinical studies of chimeric antigen receptor engineered T cells for treatment of childhood cancer]

Nowadays, the 5-year survival rate of childhood cancer patients can be more than 80%, but some patients with relapse and refractory cancers have shown no good response to traditional strategies. Chimeric antigen receptor engineered T (CAR-T) cell therapy is promising for these patients. CAR-T cells recognize the tumor-associated antigens in a non-major histocompatibility complex-restricted manner, so their anti-tumor ability is enhanced. There are four generations of CAR-T cells now. The complete remission rate of pediatric patients with relapse and refractory acute lymphoblastic leukemia can be as high as 90% when treated with CD19-targeting CAR-T cells. Furthermore, CAR-T cell therapy can also be used to bridge to transplantation and donor CAR-T cell infusion can be a strategy to prevent relapse after hematopoietic stem cell transplantation. As to solid tumors, only patients with neuroblastoma present good response to the GD2-targeting CAR-T cell therapy. The toxic or side effects of CAR-T cell therapy include cytokine release syndrome, off-tumor effect, tumor lysis syndrome, and insertion mutation. Although the CD19-targeting CAR-T cell therapy for childhood cancer can result in a high remission rate, the relapse rate is high, including CD19⁺ and CD19^- relapse. The mechanisms for relapse merit further investigatio.

Cytokine Release Syndrome: Inpatient Care for Side Effects of CAR T-Cell Therapy

BACKGROUND

Pediatric patients with relapsed and refractory acute lymphoblastic leukemia are more often being treated with chimeric antigen receptor (CAR) T-cell therapy. As with any new therapy, the management of this patient population has a unique set of challenges. The side effects of this therapy can range from mild to severe, with cytokine release syndrome being the most common reason for hospitalization.
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OBJECTIVES

This article presents common side effects, treatments, and challenges of caring for hospitalized patients who have received CAR T-cell therapy.
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METHODS

A case study is used to illustrate a patient's inpatient hospitalization course after receiving CAR T-cell therapy, including the management of treatment-related toxicities.
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FINDINGS

As treatments emerge, nurses will be challenged with learning the associated side effects and toxicities. CAR T-cell therapy can result in a unique trajectory of potential symptoms and the potential for complete resolution of disease.

Concise Review: Emerging Principles from the Clinical Application of Chimeric Antigen Receptor T Cell Therapies for B Cell Malignancies

Gene-engineered T cell therapies are soon to be United States Food and Drug Administration (FDA) approved for at least two types of B cell malignancies in pediatric and adult patients, in the form of CD19 targeted chimeric antigen receptor T (CAR T) cell therapy. This represents a triumph of a true bench to bedside clinical translation of a therapy that was conceived of in the early 1990s. Clinical results have demonstrated efficacious responses in patients with the CD19 positive diseases B cell acute lymphoblastic leukemia and diffuse large B cell lymphoma. However, significant challenges have emerged, including worrisome immune-related toxicities, therapy resistance, and understanding how to administer CD19 CAR T cells in clinical practice. Although much remains to be learned, pioneering clinical trials have led to foundational insights about the clinical translation of this novel therapy. Here, we review the "lessons learned" from the pre-clinical and human experience with CAR T cell therapy. Stem Cells 2018;36:36-44.

CAR T Therapy Targeting ICAM-1 Eliminates Advanced Human Thyroid Tumors

Purpose: Poorly differentiated thyroid cancer and anaplastic thyroid cancer (ATC) are rare yet lethal malignancies with limited treatment options. Many malignant tumors, including papillary thyroid cancer (PTC) and ATC, are associated with increased expression of ICAM-1, providing a rationale for utilizing ICAM-1-targeting agents for the treatment of aggressive cancer. We developed a third-generation chimeric antigen receptor (CAR) targeting ICAM-1 to leverage adoptive T-cell therapy as a new treatment modality.Experimental Design: ICAM-1 CAR T cells were applied to multiple malignant and nonmalignant target cells to investigate specific target cell death and "off-tumor" toxicity in vitroIn vivo therapeutic efficacy of ICAM-1 CAR T cells was examined in ATC mouse models established from a cell line and patient-derived tumors that rapidly develop systemic metastases.Results: ICAM-1 CAR T cells demonstrated robust and specific killing of PTC and ATC cell lines in vitro Interestingly, although certain ATC cell lines showed heterogeneous levels of ICAM-1 expression, addition of cytotoxic CAR T cells induced increased ICAM-1 expression such that all cell lines became targetable. In mice with systemic ATC, a single administration of ICAM-1 CAR T cells mediated profound tumor killing that resulted in long-term remission and significantly improved survival. Patient-derived ATC cells overexpressed ICAM-1 and were largely eliminated by autologous ICAM-1 CAR T cells in vitro and in animal models.Conclusions: Our findings are the first demonstration of CAR T therapy against both a metastatic, thyroid cancer cell line and advanced ATC patient-derived tumors that exhibit dramatic therapeutic efficacy and survival benefit in animal studies. Clin Cancer Res; 23(24); 7569-83. ©2017 AACR.

Chimeric Antigen Receptor T cells for B Cell Neoplasms: Choose the Right CAR for You

Genetic redirection of T lymphocytes allows us to unleash these potent cellular immune effectors against cancer. Chimeric antigen receptor (CAR) T cells are the best-in-class example that genetic engineering of T cells can lead to deep and durable responses, as has been shown in several clinical trials for CD19+ B cell malignancies. As a consequence, in the last few years, several academic institutions and commercial partners have started developing anti-CD19 CAR T cell products. Although most of these T cell products are highly effective in vivo, basic differences among them can generate different performance characteristics and thereby impact their long-term clinical outcome. Several strategies are being implemented in order to solve the current open issues of CART19 therapy: (i) increasing efficacy against indolent B cell leukemias and lymphomas, (ii) avoiding or preventing antigen-loss relapses, (iii) reducing and managing toxicity, and (iv) bringing this CART therapy to routine clinical practice. The field of CART therapies is thriving, and exciting new avenues are opening for both scientists and patients.