CAR T-Cell Therapy in Hematologic Malignancies: Clinical Role, Toxicity, and Unanswered Questions

Engineering of potent CAR NK cells using non-viral Sleeping Beauty transposition from minimalistic DNA vectors

Natural killer (NK) cells have high intrinsic cytotoxic capacity, and clinical trials have demonstrated their safety and efficacy for adoptive cancer therapy. Expression of chimeric antigen receptors (CARs) enhances NK cell target specificity, with these cells applicable as off-the-shelf products generated from allogeneic donors. Here, we present for the first time an innovative approach for CAR NK cell engineering employing a non-viral Sleeping Beauty (SB) transposon/transposase-based system and minimized DNA vectors termed minicircles. SB-modified peripheral blood-derived primary NK cells displayed high and stable CAR expression and more frequent vector integration into genomic safe harbors than lentiviral vectors. Importantly, SB-generated CAR NK cells demonstrated enhanced cytotoxicity compared with non-transfected NK cells. A strong antileukemic potential was confirmed using established acute lymphocytic leukemia cells and patient-derived primary acute B cell leukemia and lymphoma samples as targets in vitro and in vivo in a xenograft leukemia mouse model. Our data suggest that the SB-transposon system is an efficient, safe, and cost-effective approach to non-viral engineering of highly functional CAR NK cells, which may be suitable for cancer immunotherapy of leukemia as well as many other malignancies.

TOP CAR with TMIGD2 as a safe and effective costimulatory domain in CAR cells treating human solid tumors

Chimeric antigen receptor (CAR)-T cell therapy shows impressive efficacy treating hematologic malignancies but requires further optimization in solid tumors. Here, we developed a TMIGD2 optimized potent/persistent (TOP) CAR that incorporated the costimulatory domain of TMIGD2, a T and NK cell costimulator, and monoclonal antibodies targeting the IgV domain of B7-H3, an immune checkpoint expressed on solid tumors and tumor vasculature. Comparing second- and third-generation B7-H3 CARs containing TMIGD2, CD28, and/or 4-1BB costimulatory domains revealed superior antitumor responses in B7-H3.TMIGD2 and B7-H3.CD28.4-1BB CAR-T cells in vitro. Comparing these two constructs using in vivo orthotopic human cancer models demonstrated that B7-H3.TMIGD2 CAR-T cells had equivalent or superior antitumor activity, survival, expansion, and persistence. Mechanistically, B7-H3.TMIGD2 CAR-T cells maintained mitochondrial metabolism; produced less cytokines; and established fewer exhausted cells, more central memory cells, and a larger CD8/CD4 T cell ratio. These studies demonstrate that the TOP CAR with TMIGD2 costimulation offered distinct benefits from CD28.41BB costimulation and is effective against solid tumors.

Clinical efficacy and safety of combined anti-BCMA and anti-CD19 CAR-T cell therapy for relapsed/refractory multiple myeloma: a systematic review and meta-analysis

Background

The low rates of durable response against relapsed/refractory multiple myeloma (RRMM) in recent studies prompt that chimeric antigen receptor (CAR)-T cell therapies are yet to be optimized. The combined anti-BCMA and anti-CD19 CAR-T cell therapy showed high clinical efficacy in several clinical trials for RRMM. We here conducted a meta-analysis to confirm its efficacy and safety.

Methods

We collected data from Embase, Web of Science, PubMed, CNKI, Wanfang and Cochrane databases up to April 2023. We extracted and evaluated data related to the efficacy and safety of combined anti-BCMA and anti-CD19 CAR-T cell therapies in RRMM patients. The data was then analyzed using RevMan5.4 and StataSE-64 software. PROSPERO number was CRD42023455002.

Results

Our meta-analysis included 12 relevant clinical trials involving 347 RRMM patients who were treated with combined anti-BCMA and anti-CD19 CAR-T cell therapies. For efficacy assessment, the pooled overall response rate (ORR) was 94% (95% CI: 91%-98%), the complete response rate (CRR) was 50% (95% CI: 29%-71%), and the minimal residual disease (MRD) negativity rate within responders was 73% (95% CI: 66%-80%). In terms of safety, the pooled all-grade cytokine release syndrome (CRS) rate was 98% (95% CI: 97%-100%), grade≥3 CRS rate was 9% (95% CI: 4%-14%), and the incidence of neurotoxicity was 8% (95% CI: 4%-11%). Of hematologic toxicity, neutropenia was 82% (95% CI: 75%-89%), anemia was 71% (95% CI: 53%-90%), thrombocytopenia was 67% (95% CI: 40%-93%) and infection was 42% (95% CI: 9%-76%). The median progression-free survival (PFS) was 12.97 months (95% CI: 6.02-19.91), and the median overall survival (OS) was 26.63 months (95% CI: 8.14-45.11).

Conclusions

As a novel immunotherapy strategy with great potential, the combined anti-BCMA and anti-CD19 CAR-T cell therapy showed high efficacy in RRMM, but its safety needs further improvement. This meta-analysis suggests possible optimization of combined CAR-T therapy.

Systematic review registration

https://www.crd.york.ac.uk/PROSPERO/, identifier CRD42023455002.

Communication About Chimeric Antigen Receptor T-Cell (CAR-T) Therapy

Chimeric Antigen Receptor T-cell (CAR-T) therapy has revolutionized the treatment of patients with hematologic malignancies, yet treatment may coincide with the potential for life-threatening toxicities. Currently, no studies have investigated how oncologists communicate with patients about CAR-T therapy or what patients and their caregivers want to know prior to consenting for CAR-T therapy. This study characterizes the content of oncologist communication with patients and caregivers about the risks and benefits of CAR-T therapy and explore the information preferences of patients and their caregivers about CAR-T therapy. We conducted a multimethod study of 20 patients with hematologic malignancies referred for CAR-T therapy at the Massachusetts General Hospital and 10 caregivers. We audio recorded the initial outpatient visit with the oncologist to review and sign consent for CAR-T therapy. We subsequently surveyed patients and caregivers about information gaps that remained after consent. We then interviewed patients and caregiver about their perceptions of oncologist communication and information preferences after the consent visit, 1 month, and 3 months post-CAR-T therapy treatment. Qualitative data analysis was conducted using the framework approach. Six major themes regarding communication about CAR-T therapy were identified: (1) oncologists create a narrative of power and innovation about CAR-T therapy, (2) oncologists set clear expectations regarding CAR-T therapy, (3) oncologists preferentially discuss positive treatment outcomes and less frequently address treatment failures or uncertainties, (4) oncologists couple their discussion about risks of CAR-T therapy with assurances about risk mitigation strategies, (5) oncologists engage in empathetic communication throughout the consent visit, (6) patients and caregivers vary in their preferences regarding communication about CAR-T therapy but largely favor a positive discourse during the consent visit and (7) patients who completed CAR-T therapy and their caregivers report significant knowledge gaps during and after treatment. Overall, patients and caregivers felt well informed about CAR T-therapy yet identified communication gaps regarding, advanced care planning, treatment failure and treatment toxicities. A predominantly positive discourse between patients, caregivers, and oncologists around CAR-T therapy leaves patients and caregivers with significant knowledge gaps about negative outcomes. Further research is needed to help oncologists communicate about treatment uncertainties and help patients and their caregivers prepare for negative outcomes of CAR-T therapy.

Discovery and preclinical development of a therapeutically active nanobody-based chimeric antigen receptor targeting human CD22

Chimeric antigen receptor (CAR) T cell therapies targeting B cell-restricted antigens CD19, CD20, or CD22 can produce potent clinical responses for some B cell malignancies, but relapse remains common. Camelid single-domain antibodies (sdAbs or nanobodies) are smaller, simpler, and easier to recombine than single-chain variable fragments (scFvs) used in most CARs, but fewer sdAb-CARs have been reported. Thus, we sought to identify a therapeutically active sdAb-CAR targeting human CD22. Immunization of an adult Llama glama with CD22 protein, sdAb-cDNA library construction, and phage panning yielded >20 sdAbs with diverse epitope and binding properties. Expressing CD22-sdAb-CAR in Jurkat cells drove varying CD22-specific reactivity not correlated with antibody affinity. Changing CD28- to CD8-transmembrane design increased CAR persistence and expression in vitro. CD22-sdAb-CAR candidates showed similar CD22-dependent CAR-T expansion in vitro, although only membrane-proximal epitope targeting CD22-sdAb-CARs activated direct cytolytic killing and extended survival in a lymphoma xenograft model. Based on enhanced survival in blinded xenograft studies, a lead CD22sdCAR-T was selected, achieving comparable complete responses to a benchmark short linker m971-scFv CAR-T in high-dose experiments. Finally, immunohistochemistry and flow cytometry confirm tissue and cellular-level specificity of the lead CD22-sdAb. This presents a complete report on preclinical development of a novel CD22sdCAR therapeutic.

Immunotherapies of acute myeloid leukemia: Rationale, clinical evidence and perspective

Acute myeloid leukemia (AML) is a prevalent hematological malignancy that exhibits a wide array of molecular abnormalities. Although traditional treatment modalities such as chemotherapy and allogeneic stem cell transplantation (HSCT) have become standard therapeutic approaches, a considerable number of patients continue to face relapse and encounter a bleak prognosis. The emergence of immune escape, immunosuppression, minimal residual disease (MRD), and other contributing factors collectively contribute to this challenge. Recent research has increasingly highlighted the notable distinctions between AML tumor microenvironments and those of healthy individuals. In order to investigate the potential therapeutic mechanisms, this study examines the intricate transformations occurring between leukemic cells and their surrounding cells within the tumor microenvironment (TME) of AML. This review classifies immunotherapies into four distinct categories: cancer vaccines, immune checkpoint inhibitors (ICIs), antibody-based immunotherapies, and adoptive T-cell therapies. The results of numerous clinical trials strongly indicate that the identification of optimal combinations of novel agents, either in conjunction with each other or with chemotherapy, represents a crucial advancement in this field. In this review, we aim to explore the current and emerging immunotherapeutic methodologies applicable to AML patients, identify promising targets, and emphasize the crucial requirement to augment patient outcomes. The application of these strategies presents substantial therapeutic prospects within the realm of precision medicine for AML, encompassing the potential to ameliorate patient outcomes.

New Biological Therapies for Multiple Myeloma

Multiple myeloma is a cancer of bone marrow plasma cells that represents approximately 10% of hematologic malignancies. Though it is typically incurable, a remarkable suite of new therapies developed over the last 25 years has enabled durable disease control in most patients. This article briefly introduces the clinical features of multiple myeloma and aspects of multiple myeloma biology that modern therapies exploit. Key current and emerging treatment modalities are then reviewed, including cereblon-modulating agents, proteasome inhibitors, monoclonal antibodies, other molecularly targeted therapies (selinexor, venetoclax), chimeric antigen receptor T cells, T cell-engaging bispecific antibodies, and antibody-drug conjugates. For each modality, mechanism of action and clinical considerations are discussed. These therapies are combined and sequenced in modern treatment pathways, discussed at the conclusion of the article, which have led to substantial improvements in outcomes for multiple myeloma patients in recent years.

Integrating CAR-T cell therapy into the management of DLBCL: what we are learning

INTRODUCTION

Chimeric Antigen Receptor ;(CAR) T cells therapies have become part of the standard of care for patients with relapsed/refractory (R/R) diffuse large B-cell lymphoma (DLBCL). The weakness of CAR-T therapies is that there are no comparative clinical trials, although many publications based on real-life data have confirmed the results obtained in pivotal studies. After several years of the commercialization of CAR-T, some points still need to be fully clarified. Healthcare professionals have questions about identifying patients who may benefit from therapy. There are aspects inherent in the accessibility of care related to improved relationships between CAR-T-delivering and referral centers.

AREAS COVERED

Open questions are inherent in the salvage and bridge therapy, predictive criteria for response and persistence of CAR-T after infusion. Managing toxicities remain a top priority and one of the points on which further knowledge is needed.

EXPERT OPINION

This review aims to describe the current landscape of CAR-T cells in DLBCL, outline their outcomes and toxicities, and explain the outstanding questions that remain to be addressed.

Toxicity Profile of Chimeric Antigen Receptor T-Cell and Bispecific Antibody Therapies in Multiple Myeloma: Pathogenesis, Prevention and Management

Multiple myeloma is the second-most common hematologic malignancy in adults worldwide. Despite ongoing advancement in therapeutic modalities, it remains an incurable disease with a 5-year survival rate of approximately 50%. The recent development and introduction of anti-BCMA immunotherapies into clinical practice, including chimeric antigen receptor T-cell (CAR-T) therapies and bispecific antibodies, has radically shifted the treatment paradigm. However, despite the promising potential of these therapies for broader application, frequent and significant adverse effects have been reported, both in short- and in long-term settings, requiring increasing awareness and vigilance in the treating team, close monitoring, and prompt interventions with a multidisciplinary approach. In this review, we will discuss the toxicities associated with CAR-T cell and bispecific antibody therapies, focusing on results from major clinical studies and real-world observations. In addition, we will emphasize on effective strategies for prevention, monitoring and management, and provide expert recommendations.

Recent Advances in CAR-Based Solid Tumor Immunotherapy

Adoptive cell therapy using chimeric antigen receptor (CAR) technology is one of the most advanced engineering platforms for cancer immunotherapy. CAR-T cells have shown remarkable efficacy in the treatment of hematological malignancies. However, their limitations in solid tumors include an immunosuppressive tumor microenvironment (TME), insufficient tumor infiltration, toxicity, and the absence of tumor-specific antigens. Although recent advances in CAR-T cell design-such as the incorporation of co-stimulatory domains and the development of armored CAR-T cells-have shown promising results in treating solid tumors, there are still challenges that need to be addressed. To overcome these limitations, other immune cells, such as natural killer (NK) cells and macrophages (M), have been developed as attractive options for efficient cancer immunotherapy of solid tumors. CAR-NK cells exhibit substantial clinical improvements with "off-the-shelf" availability and low toxicity. CAR-M cells have promising therapeutic potential because macrophages can infiltrate the TME of solid tumors. Here, we review the recent advances and future perspectives associated with engineered immune cell-based cancer immunotherapies for solid tumors. We also summarize ongoing clinical trials investigating the safety and efficacy of engineered immune cells, such as CAR-T, CAR-NK, and CAR-M, for targeting solid tumors.

The magic of small-molecule drugs during ex vivo expansion in adoptive cell therapy

In the past decades, advances in the use of adoptive cellular therapy to treat cancer have led to unprecedented responses in patients with relapsed/refractory or late-stage malignancies. However, cellular exhaustion and senescence limit the efficacy of FDA-approved T-cell therapies in patients with hematologic malignancies and the widespread application of this approach in treating patients with solid tumors. Investigators are addressing the current obstacles by focusing on the manufacturing process of effector T cells, including engineering approaches and ex vivo expansion strategies to regulate T-cell differentiation. Here we reviewed the current small-molecule strategies to enhance T-cell expansion, persistence, and functionality during ex vivo manufacturing. We further discussed the synergistic benefits of the dual-targeting approaches and proposed novel vasoactive intestinal peptide receptor antagonists (VIPR-ANT) peptides as emerging candidates to enhance cell-based immunotherapy.

Real-life experiences with CAR T-cell therapy with idecabtagene vicleucel (ide-cel) for triple-class exposed relapsed/refractory multiple myeloma patients

BACKGROUND

Chimeric antigen receptor (CAR) T-cell therapy has revolutionized the treatment landscape of relapsed/refractory multiple myeloma (RRMM), leading to unprecedented responses in this patient population. Idecabtagene vicleucel (ide-cel) has been recently approved for treatment of triple-class exposed RRMM. We report real-life experiences with the commercial use of ide-cel in RRMM patients.

METHODS

We performed a retrospective analysis of the first 16 triple-class exposed RRMM patients treated with ide-cel at a single academic center. We assessed toxicities, response to treatment, CAR T expansion and soluble BCMA (sBCMA) levels.

RESULTS

We identified 16 consecutive RRMM patients treated with ide-cel between 06-10/2022. Median age was 69 years, 6 (38%) patients had high-risk cytogenetics, 3 (19%) R-ISS stage III, and 5 (31%) extramedullary disease. Median number of previous treatment lines was 6 (3-12). Manufacturing success rate was 88% (6% required second lymphapheresis, 6% received an out-of-specification product). At 3 months, the overall response rate (ORR) was 69% (44% sCR, 6% CR, 19% VGPR). Cytokine release syndrome (CRS) occurred in 15 (94%) patients (88% G1, 6% G2), immune effector-cell associated neurotoxicity syndrome (ICANS) in 1 (6% G1), febrile neutropenia in 11 (69%), and infections in 5 (31%). Prolonged hematologic toxicity occurred in 4/16 (25%) patients. Other non-hematological toxicities were elevated hepatic enzymes (38%), colitis (6%, G3) and DIC (6%, G2). Responses were more frequent in patients with higher CAR T expansion (100% vs 38%), and lack of decrease or plateau of sBCMA levels was typically observed in non-responders.

CONCLUSIONS

We report one of the first cohorts of RRMM treated with commercial ide-cel. The ORR was 69% and safety profile was manageable, but prolonged hematologic toxicity still represents a major challenge. Responses correlated with in vivo CAR T cell expansion, underlining the need of further research to optimize CAR T expansion.

Advancing CAR T cell therapy through the use of multidimensional omics data

Despite the notable success of chimeric antigen receptor (CAR) T cell therapies in the treatment of certain haematological malignancies, challenges remain in optimizing CAR designs and cell products, improving response rates, extending the durability of remissions, reducing toxicity and broadening the utility of this therapeutic modality to other cancer types. Data from multidimensional omics analyses, including genomics, epigenomics, transcriptomics, T cell receptor-repertoire profiling, proteomics, metabolomics and/or microbiomics, provide unique opportunities to dissect the complex and dynamic multifactorial phenotypes, processes and responses of CAR T cells as well as to discover novel tumour targets and pathways of resistance. In this Review, we summarize the multidimensional cellular and molecular profiling technologies that have been used to advance our mechanistic understanding of CAR T cell therapies. In addition, we discuss current applications and potential strategies leveraging multi-omics data to identify optimal target antigens and other molecular features that could be exploited to enhance the antitumour activity and minimize the toxicity of CAR T cell therapy. Indeed, fully utilizing multi-omics data will provide new insights into the biology of CAR T cell therapy, further accelerate the development of products with improved efficacy and safety profiles, and enable clinicians to better predict and monitor patient responses.

CAR T-Cell Persistence Correlates with Improved Outcome in Patients with B-Cell Lymphoma

Chimeric antigen receptor (CAR) T-cell therapy has led to profound and durable tumor responses in a relevant subset of patients with relapsed/refractory (r/r) B-cell lymphomas. Still, some patients show insufficient benefit or relapse after CAR T-cell therapy. We performed a retrospective study to investigate the correlation between CAR T-cell persistence in the peripheral blood (PB) at 6 months, assessed by droplet digital PCR (ddPCR), with CAR T-cell treatment outcome. 92 patients with r/r B-cell lymphomas were treated with CD19-targeting CAR T-cell therapies at our institution between 01/2019–08/2022. Six months post-treatment, 15 (16%) patients had no detectable circulating CAR-T constructs by ddPCR. Patients with CAR T-cell persistence had a significantly higher CAR T-cell peak (5432 vs. 620 copies/ug cfDNA, p = 0.0096), as well as higher incidence of immune effector cell-associated neurotoxicity syndrome (37% vs. 7%, p = 0.0182). After a median follow-up of 8.5 months, 31 (34%) patients relapsed. Lymphoma relapses were less frequent among patients with CAR T-cell persistence (29% vs. 60%, p = 0.0336), and CAR T-cell persistence in the PB at 6 months was associated with longer progression-free survival (PFS) (HR 2.79, 95% CI: 1.09–7.11, p = 0.0319). Moreover, we observed a trend towards improved overall survival (OS) (HR 1.99, 95% CI: 0.68–5.82, p = 0.2092) for these patients. In our cohort of 92 B-cell lymphomas, CAR T-cell persistence at 6 months was associated with lower relapse rates and longer PFS. Moreover, our data confirm that 4-1BB-CAR T-cells have a longer persistence as compared to CD-28-based CAR T-cells.

Early Use of Corticosteroids following CAR T-Cell Therapy Correlates with Reduced Risk of High-Grade CRS without Negative Impact on Neurotoxicity or Treatment Outcome

BACKGROUND

Chimeric antigen receptor T-cell therapy (CAR T-cell therapy) is associated with potentially life-threatening toxicities, most commonly cytokine release syndrome (CRS) and immune-effector-cell-associated neurotoxicity syndrome (ICANS). These frequent adverse events are managed with the IL-6 receptor antagonist tocilizumab and/or corticosteroids. The prophylactic and early use of corticosteroids for CRS and ICANS have previously been reported, but eventual negative impacts on CAR T-cell efficacy are feared.

METHODS

Retrospective comparative analysis of two patient cohorts with hematological malignancies treated with CAR T-cell therapy: 43 patients received early administration of 10 mg dexamethasone preceding each dose of tocilizumab ("early corticosteroid/ tocilizumab", EcsTcz cohort) vs. 40 patients who received tocilizumab alone ("tocilizumab alone", Tcz cohort) for treatment of low-grade CRS.

RESULTS

Despite overall higher CRS incidence (91% vs. 70%; p = 0.0249), no high-grade CRS was observed (0% vs. 10%; p = 0.0497) among patients receiving early corticosteroids in combination with tocilizumab. In terms of neurotoxicity, no worsening regarding incidence of ICANS (30% vs. 33%; p = 0.8177) or high-grade ICANS (20% vs. 14%; p = 0.5624) was observed in the EcsTcz cohort. Moreover, overall response rates (80% vs. 77%; p = 0.7936), complete response rates (50% vs. 44%; p = 0.6628), progression-free survival (p = 0.6345) and overall survival (p = 0.1215) were comparable for both cohorts.

CONCLUSIONS

Our study suggests that the early use of corticosteroids in combination with the standard tocilizumab schedule for low-grade CRS following CAR T-cell therapy may significantly reduce the risk of high-grade CRS without negative impact on neurotoxicity or treatment outcome.

Agents contributing to secondary immunodeficiency development in patients with multiple myeloma, chronic lymphocytic leukemia and non-Hodgkin lymphoma: A systematic literature review

Introduction

Patients with hematological malignancies (HMs), like chronic lymphocytic leukemia (CLL), multiple myeloma (MM), and non-Hodgkin lymphoma (NHL), have a high risk of secondary immunodeficiency (SID), SID-related infections, and mortality. Here, we report the results of a systematic literature review on the potential association of various cancer regimens with infection rates, neutropenia, lymphocytopenia, or hypogammaglobulinemia, indicative of SID.

Methods

A systematic literature search was performed in 03/2022 using PubMed to search for clinical trials that mentioned in the title and/or abstract selected cancer (CLL, MM, or NHL) treatments covering 12 classes of drugs, including B-lineage monoclonal antibodies, CAR T therapies, proteasome inhibitors, kinase inhibitors, immunomodulators, antimetabolites, anti-tumor antibiotics, alkylating agents, Bcl-2 antagonists, histone deacetylase inhibitors, vinca alkaloids, and selective inhibitors of nuclear export. To be included, a publication had to report at least one of the following: percentages of patients with any grade and/or grade ≥3 infections, any grade and/or grade ≥3 neutropenia, or hypogammaglobulinemia. From the relevant publications, the percentages of patients with lymphocytopenia and specific types of infection (fungal, viral, bacterial, respiratory [upper or lower respiratory tract], bronchitis, pneumonia, urinary tract infection, skin, gastrointestinal, and sepsis) were collected.

Results

Of 89 relevant studies, 17, 38, and 34 included patients with CLL, MM, and NHL, respectively. In CLL, MM, and NHL, any grade infections were seen in 51.3%, 35.9% and 31.1% of patients, and any grade neutropenia in 36.3%, 36.4%, and 35.4% of patients, respectively. The highest proportion of patients with grade ≥3 infections across classes of drugs were: 41.0% in patients with MM treated with a B-lineage monoclonal antibody combination; and 29.9% and 38.0% of patients with CLL and NHL treated with a kinase inhibitor combination, respectively. In the limited studies, the mean percentage of patients with lymphocytopenia was 1.9%, 11.9%, and 38.6% in CLL, MM, and NHL, respectively. Two studies reported the proportion of patients with hypogammaglobulinemia: 0-15.3% in CLL and 5.9% in NHL (no studies reported hypogammaglobulinemia in MM).

Conclusion

This review highlights cancer treatments contributing to infections and neutropenia, potentially related to SID, and shows underreporting of hypogammaglobulinemia and lymphocytopenia before and during HM therapies.

Immunotherapy approaches for rare pediatric solid tumors: advances and future directions

PURPOSE OF REVIEW

Immunotherapy for pediatric tumors is rapidly evolving. From major successes in pediatric hematologic malignancies, immunotherapy utility increased in the pediatric solid tumor landscape. Numerous pediatric solid tumors are defined as rare with limitations in diagnosis and treatment. This review will describe four major immunotherapies used in pediatrics and discuss results seen in rare pediatric tumors. We will also briefly review the challenges of immunotherapy in solid tumors and opportunities to drive this therapy forward.

RECENT FINDINGS

Despite rare success employing immunotherapy for pediatric solid tumors, recently there have been several successes in pediatric rare solid tumors. After describing the evolving landscape of rare pediatric tumors, we will demonstrate the successes or disappointments of immunotherapy. We will describe the mechanism of four immunotherapies used in the pediatrics, followed by the published results. Finally, we will discuss the challenges and opportunities for immunotherapies in pediatric rare tumors.

SUMMARY

Pediatric rare tumors are lacking in treatment options. Despite numerous disappointments utilizing immunotherapies in the more common pediatric solid tumors, there have been several successes within the pediatric rare tumor landscape. Much work is still needed to enhance our understanding and knowledge on utilizing these immunotherapies for pediatric rare solid tumors.

Efficacy and safety of CD22-specific and CD19/CD22-bispecific CAR-T cell therapy in patients with hematologic malignancies: A systematic review and meta-analysis

Background

CD22 single and CD19/CD22 bispecific targeted chimeric antigen receptor T (CAR-T) cell therapy are promising immunotherapy modalities for the treatment of hematologic malignancies. The aim of this study was to assess the efficacy and safety of CD22 and CD19/CD22 targeted CAR-T cell therapy by summarizing the existing evidence.

Methods

Electronic databases including PubMed, Embase, and Scopus were comprehensively searched from inception up to November 30, 2022. Pooled response rates and minimal residual disease (MRD) negative response rates, cytokine release syndrome (CRS) rates and neurotoxicity rates were calculated. Subgroup analysis was performed based on the type of immunotherapy.

Results

Ten clinical studies including 194 patients with hematologic malignancies were included after a systematical screening of literature. The pooled complete response (CR) rates of CD22 and CD19/CD22 CAR-T cell therapy for relapsed or refractory B-cell lymphoblastic leukemia (B-ALL) were 0.75 (95% CI: 0.60 - 0.88) and 0.87 (95% CI: 0.76 - 0.96). The overall MRD negative response rates of CD22 and CD19/CD22 CAR-T were 0.54 (95% CI: 0.42 - 0.66) and 0.91 (95% CI: 0.47 - 0.88). Pooled CRS rates of CD22 targeted and CD19/CD22 targeted immunotherapy were 0.92 (95% CI: 0.82 - 0.98) and 0.94 (95% CI: 0.82 - 1.00), respectively.

Conclusion

Both CD22 and CD19/CD22 CAR-T immunotherapy demonstrated favorable efficacy and acceptable adverse events in the treatment of hematologic malignancies. Well-designed and large sample-sized clinical trials are warranted.

Effect of granulocyte colony-stimulating factor on toxicities after CAR T cell therapy for lymphoma and myeloma

Chimeric antigen receptor T cells (CAR T) are groundbreaking therapies but may cause significant toxicities including cytokine release syndrome (CRS), immune effector cell-associated neurotoxicity syndrome (ICANS), and cytopenias. Granulocyte colony-stimulating factor (G-CSF) is often used to mitigate neutropenia after CAR T, but there is no consensus recommended strategy due to hypothesized, but largely unknown risks of exacerbating toxicities. To investigate the impact of G-CSF, we retrospectively analyzed 197 patients treated with anti-CD19 CAR T for lymphoma and 47 patients treated with anti-BCMA CAR T for multiple myeloma. In lymphoma, 140 patients (71%) received prophylactic G-CSF before CAR T (mostly pegylated G-CSF) and were compared with 57 patients (29%) treated with G-CSF after CAR T or not exposed. Prophylactic G-CSF was associated with faster neutrophil recovery (3 vs. 4 days, P < 0.01) but did not reduce recurrent neutropenia later. Prophylactic G-CSF was associated with increased grade ≥2 CRS (HR 2.15, 95% CI 1.11-4.18, P = 0.02), but not ICANS. In multiple myeloma, prophylactic G-CSF was not used; patients were stratified by early G-CSF exposure (≤2 days vs. ≥3 days after CAR T or no exposure), with no significant difference in toxicities. Future trials should clarify the optimal G-CSF strategy to improve outcomes after CAR T.

Natural killer cells in antitumour adoptive cell immunotherapy

Natural killer (NK) cells comprise a unique population of innate lymphoid cells endowed with intrinsic abilities to identify and eliminate virally infected cells and tumour cells. Possessing multiple cytotoxicity mechanisms and the ability to modulate the immune response through cytokine production, NK cells play a pivotal role in anticancer immunity. This role was elucidated nearly two decades ago, when NK cells, used as immunotherapeutic agents, showed safety and efficacy in the treatment of patients with advanced-stage leukaemia. In recent years, following the paradigm-shifting successes of chimeric antigen receptor (CAR)-engineered adoptive T cell therapy and the advancement in technologies that can turn cells into powerful antitumour weapons, the interest in NK cells as a candidate for immunotherapy has grown exponentially. Strategies for the development of NK cell-based therapies focus on enhancing NK cell potency and persistence through co-stimulatory signalling, checkpoint inhibition and cytokine armouring, and aim to redirect NK cell specificity to the tumour through expression of CAR or the use of engager molecules. In the clinic, the first generation of NK cell therapies have delivered promising results, showing encouraging efficacy and remarkable safety, thus driving great enthusiasm for continued innovation. In this Review, we describe the various approaches to augment NK cell cytotoxicity and longevity, evaluate challenges and opportunities, and reflect on how lessons learned from the clinic will guide the design of next-generation NK cell products that will address the unique complexities of each cancer.

The Role of RNA-Binding Proteins in Hematological Malignancies

Hematological malignancies comprise a plethora of different neoplasms, such as leukemia, lymphoma, and myeloma, plus a myriad of dysplasia, such as myelodysplastic syndromes or anemias. Despite all the advances in patient care and the development of new therapies, some of these malignancies remain incurable, mainly due to resistance and refractoriness to treatment. Therefore, there is an unmet clinical need to identify new biomarkers and potential therapeutic targets that play a role in treatment resistance and contribute to the poor outcomes of these tumors. RNA-binding proteins (RBPs) are a diverse class of proteins that interact with transcripts and noncoding RNAs and are involved in every step of the post-transcriptional processing of transcripts. Dysregulation of RBPs has been associated with the development of hematological malignancies, making them potential valuable biomarkers and potential therapeutic targets. Although a number of dysregulated RBPs have been identified in hematological malignancies, there is a critical need to understand the biology underlying their contribution to pathology, such as the spatiotemporal context and molecular mechanisms involved. In this review, we emphasize the importance of deciphering the regulatory mechanisms of RBPs to pinpoint novel therapeutic targets that could drive or contribute to hematological malignancy biology.

Circulating inflammatory cells in patients with metastatic breast cancer: Implications for treatment

Adaptive and innate immune cells play a crucial role as regulators of cancer development.

Inflammatory cells in blood flow seem to be involved in pro-tumor activities and contribute to breast cancer progression. Circulating lymphocyte ratios such as the platelet-lymphocytes ratio (PLR), the monocyte-lymphocyte ratio (MLR) and the neutrophil-lymphocyte ratio (NLR) are new reproducible, routinely feasible and cheap biomarkers of immune response. These indexes have been correlated to prognosis in many solid tumors and there is growing evidence on their clinical applicability as independent prognostic markers also for breast cancer.

In this review we give an overview of the possible value of lymphocytic indexes in advanced breast cancer prognosis and prediction of outcome. Furthermore, targeting the immune system appear to be a promising therapeutic strategy for breast cancer, especially macrophage-targeted therapies. Herein we present an overview of the ongoing clinical trials testing systemic inflammatory cells as therapeutic targets in breast cancer.

The Past, Present, and Future of Non-Viral CAR T Cells

Adoptive transfer of chimeric antigen receptor (CAR) T lymphocytes is a powerful technology that has revolutionized the way we conceive immunotherapy. The impressive clinical results of complete and prolonged response in refractory and relapsed diseases have shifted the landscape of treatment for hematological malignancies, particularly those of lymphoid origin, and opens up new possibilities for the treatment of solid neoplasms. However, the widening use of cell therapy is hampered by the accessibility to viral vectors that are commonly used for T cell transfection. In the era of messenger RNA (mRNA) vaccines and CRISPR/Cas (clustered regularly interspaced short palindromic repeat-CRISPR-associated) precise genome editing, novel and virus-free methods for T cell engineering are emerging as a more versatile, flexible, and sustainable alternative for next-generation CAR T cell manufacturing. Here, we discuss how the use of non-viral vectors can address some of the limitations of the viral methods of gene transfer and allow us to deliver genetic information in a stable, effective and straightforward manner. In particular, we address the main transposon systems such as Sleeping Beauty (SB) and piggyBac (PB), the utilization of mRNA, and innovative approaches of nanotechnology like Lipid-based and Polymer-based DNA nanocarriers and nanovectors. We also describe the most relevant preclinical data that have recently led to the use of non-viral gene therapy in emerging clinical trials, and the related safety and efficacy aspects. We will also provide practical considerations for future trials to enable successful and safe cell therapy with non-viral methods for CAR T cell generation.

CAR T Cell Therapy for Chronic Lymphocytic Leukemia: Successes and Shortcomings

Chimeric antigen receptor T (CAR T) cell therapy achieved remarkable success in B-cell leukemia and lymphoma which led to its incorporation in treatment protocols for these diseases. CAR T cell therapy for chronic lymphocytic leukemia (CLL) patients showed less success compared to other malignant tumors. In this review, we discuss the published results regarding CAR T cell therapy of CLL, possible mechanisms of failures and expected developments.

Changing Landscape of Systemic Therapy in Biliary Tract Cancer

Biliary tract cancers (BTC) are often diagnosed at advanced stages and have a grave outcome due to limited systemic options. Gemcitabine and cisplatin combination (GC) has been the first-line standard for more than a decade. Second-line chemotherapy (CT) options are limited. Targeted therapy or TT (fibroblast growth factor 2 inhibitors or FGFR2, isocitrate dehydrogenase 1 or IDH-1, and neurotrophic tyrosine receptor kinase or NTRK gene fusions inhibitors) have had reasonable success, but <5% of total BTC patients are eligible for them. The use of immune checkpoint inhibitors (ICI) such as pembrolizumab is restricted to microsatellite instability high (MSI-H) patients in the first line. The success of the TOPAZ-1 trial (GC plus durvalumab) is promising, with numerous trials underway that might soon bring targeted therapy (pemigatinib and infrigatinib) and ICI combinations (with CT or TT in microsatellite stable cancers) in the first line. Newer targets and newer agents for established targets are being investigated, and this may change the BTC management landscape in the coming years from traditional CT to individualized therapy (TT) or ICI-centered combinations. The latter group may occupy major space in BTC management due to the paucity of targetable mutations and a greater toxicity profile.