Blinatumomab: a CD19/CD3 bispecific T cell engager (BiTE) with unique anti-tumor efficacy

Blinatumomab in combination with olverembatinib and concurrent intrathecal chemotherapy successfully treated a chronic myeloid leukemia relapse with central nervous system blast crisis: case report and literature review

OBJECTIVE

Central nervous system (CNS) blast crisis in chronic myeloid leukemia (CML) is rare and presents a significant treatment challenge due to the limited ability of many systemic therapies to penetrate the blood-brain barrier (BBB). This case highlights the need for effective treatment strategies.

CASE REPORT

This case report describes a 43-year-old man diagnosed with CML who developed a CNS blast crisis followed by bone marrow relapse while receiving flumatinib.

DISCUSSION

The patient achieved complete remission (CR) in both the bone marrow and CNS after receiving a combination of blinatumomab and olverembatinib, along with weekly intrathecal chemotherapy.

CONCLUSIONS

The combination of blinatumomab, olverembatinib, and concurrent intrathecal chemotherapy may be an effective treatment strategy for CML progression, particularly in cases with CNS involvement.

T-Cell-Dependent Bispecific IgGs Protect Aged Mice From Lethal SARS-CoV-2 Infection

T-cell ageing may be a key factor in the disproportionate severity of coronavirus disease 2019 (COVID-19) in older populations. For hospitalized COVID-19 patients, treatment involving the use of monoclonal antibodies with the ability to neutralize SARS-CoV-2 usually involves the administration of high doses but has not been very effective at preventing complications or fatality, highlighting the need for additional research into anti-SARS-CoV-2 therapies, particularly for older populations. In this study, it is discovered that older persons with a severe SARS-CoV-2 infection has weaker T-cell responses. Therefore the development and characterization of spike-targeting T-cell-dependent bispecific (TDB) full-length human immunoglobulin Gs with enhanced efficacy in the treatment of COVID-19 is described. Using S-targeting TDBs, polyclonal T cells are guided to target and destroy S-expressing cells, preventing the cell-to-cell transmission of SARS-CoV-2 and thereby eliminating the need for SARS-CoV-2-specific immunity. Using animal models of COVID-19, it is shown that the selective activation of T cells improves the efficiency of treatment in preinfected mice by attenuating disease-induced weight loss and death. The significance of T-cell-based immunity during infection is highlighted by the findings. These results have implications for better clinical effectiveness of therapies for COVID-19 and the development of T-cell-dependent medicines for the elderly population.

A ROR1 targeted bispecific T cell engager shows high potency in the pre-clinical model of triple negative breast cancer

BACKGROUND

Triple negative breast cancer (TNBC) is an aggressive breast cancer subtype characterized with poor prognosis and high metastatic potential. Although traditional chemotherapy, radiation, and surgical resection remain the standard treatment options for TNBC, bispecific antibody-based immunotherapy is emerging as new strategy in TNBC treatment. Here, we found that the receptor tyrosine kinase-like Orphan Receptor 1 (ROR1) was highly expressed in TNBC but minimally expressed in normal tissue. A bispecific ROR1-targeted CD3 T cell engager (TCE) was designed in IgG-based format with extended half-life.

METHOD

The expression of ROR1 in TNBC was detected by RT-qPCR and immunohistology analysis. The killing of ROR1/CD3 antibody on TNBC cells was determined by the in vitro cytotoxicity assay and in vivo PBMC reconstituted mouse model. The activation of ROR1/CD3 on T cells was analyzed by the flow cytometry and ELISA assay. Pharmacokinetics study of ROR1/CD3 was performed in mouse.

RESULTS

The ROR1/CD3 TCE triggered T cell activation and proliferation, which showed potent and specific killing to TNBC cells in ROR1-depedent manner. In vivo mouse model indicated that ROR1/CD3 TCE redirected the cytotoxic activity of T cells to lyse TNBC cells and induced significant tumor regression. Additionally, the ROR1/CD3 bispecific antibody exhibited an extended half-life in mouse, which may enable intermittent administration in clinic.

CONCLUSIONS

Collectively, these results demonstrated that ROR1/CD3 TCE has a promising efficacy profile in preclinical studies, which suggested it as a possible option for the treatment of ROR1-expressing TNBC.

Efficacy of natural killer T and gammadelta T cells in mesothelin-targeted immunotherapy of pancreatic cancer

Current pancreatic cancer immunotherapy focused on alphabeta (αβ) T cells, either through CD3-engaged bispecific antibodies or CAR-T. Despite their promise, dose-limited toxicity (DLT) remains a challenge in clinical practice. In light of these concerns, there is a growing interest in exploring alternative T cell types, natural killer T (NKT) cells and gammadelta (γδ) T cells, that possess the capacity to lyse tumors while potentially offering a safer therapeutic profile with fewer side effects. These cells present a compelling alternative that warrants a comprehensive evaluation of their therapeutic potential and safety profile. This study employed a MSLN/CD3 bispecific antibody to compare the anti-tumor activity of NKT and γδT cells with peripheral blood mononuclear cells (PBMCs) as controls, both in vitro and in vivo. This study demonstrated that MSLN/CD3 BsAb effectively activated and recruited PBMCs, NKT and γδT. Furthermore, under the influence of MSLN/CD3 BsAb, γδT and NKT cells exhibited notably superior anti-tumor activity compared to PBMCs, both in vitro and in vivo, while demonstrating low cytokine release. γδT cells showed almost negligible toxic side effects. In addition, the systemic administration of NKT and γδT cells activators, α-galactosylceramide (α-GalCer) and Zoledronate, could enhance the anti-tumor effect of MSLN/CD3 bsAb, with no apparent toxicity. NKT and γδT cells are promising synergistic therapeutic cell types that may overcome the limitations of CD3 bispecific antibodies in pancreatic tumor treatments, offering a new perspective for clinical applications in immunotherapy.

Tri-specific tribodies targeting 5T4, CD3, and immune checkpoint drive stronger functional T-cell responses than combinations of antibody therapeutics

One of the most promising cancer immunotherapies is based on bi-specific T-cell engagers (BiTEs) that simultaneously bind with one arm to a tumor-associated antigen on tumor cells and with the other one to CD3 complex on T cells to form a TCR-MHC independent immune synapse. We previously generated four novel tri-specific tribodies made up of a Fab targeting 5T4, an oncofetal tumor antigen expressed on several types of tumors, a scFv targeting CD3 on T cells, and an additional scFv specific for an immune checkpoint (IC), such as PD-1, PD-L1 or LAG-3. To verify their advantages over the combinations of BiTEs (CD3/TAA) with IC inhibitors, recently used to overcome tumor immunosuppressive environment, here we tested their functional properties in comparison with clinically validated mAbs targeting the same ICs, used alone or in combination with a control bi-specific devoid of immunomodulatory scFvs, called 53 P. We found that the novel tri-specific tribodies activated human peripheral blood mononuclear cells more efficiently than clinically validated mAbs (atezolizumab, pembrolizumab, and relatlimab) either used alone or in combination with 53 P, leading to a stronger tumor cytotoxicity and cytokines release. In particular, 53L10 tribody targeting PD-L1 displayed much more potent effects than the combination of 53 P with all the clinically validated mAbs and led to complete tumor regression in vivo, showing much higher efficacy than the combination of 53 P and atezolizumab. We shed light on the molecular basis of this potentiated anti-tumor activity by evidencing that the insertion of the anti-PD-L1 moiety in 53L10 led not only to stronger binding of the tri-specific to tumor cells but also efficiently blocked the effects of increased PD-L1 on tumor cells, induced by IFNγ secretion also due to T-cell activation. These results are important also for the design of novel T-cell engagers targeting other tumor antigens.

Multimodal targeting chimeras enable integrated immunotherapy leveraging tumor-immune microenvironment

Although immunotherapy has revolutionized cancer treatment, its efficacy is affected by multiple factors, particularly those derived from the complexity and heterogeneity of the tumor-immune microenvironment (TIME). Strategies that simultaneously and synergistically engage multiple immune cells in TIME remain highly desirable but challenging. Herein, we report a multimodal and programmable platform that enables the integration of multiple therapeutic modules into single agents for tumor-targeted co-engagement of multiple immune cells within TIME. We developed the triple orthogonal linker (T-Linker) technology to integrate various therapeutic small molecules and biomolecules as multimodal targeting chimeras (Multi-TACs). The EGFR-CD3-PDL1 Multi-TAC facilitated T-dendritic cell co-engagement to target solid tumors with excellent efficacy, as demonstrated in vitro, in several humanized mouse models and in patient-derived tumor models. Furthermore, Multi-TACs were constructed to coordinate T cells with other immune cell types. The highly modular and programmable feature of our Multi-TACs may find broad applications in immunotherapy and beyond.

Cancer Therapy-Induced Encephalitis

Encephalitis associated with cancer therapies is a rare but serious complication that can significantly impact patients' quality of life and it requires prompt identification and management. Over the past two decades, immunotherapy-particularly immune checkpoint inhibitors-has become a cornerstone of cancer treatment, with up to half of metastatic cancer patients in economically developed countries now receiving these therapies. The widespread adoption of immunotherapy has led to improved survival rates and long-term remissions, even in patients with advanced metastatic disease. However, as immune modulators, these therapies can trigger a range of immune-related adverse events, including a variety of novel neurological toxicities. Among these, encephalitis is of particular concern due to its potential severity, which can compromise treatment outcomes. This review aims to provide a comprehensive overview of the literature on this condition, highlighting optimal diagnostic strategies and management approaches to mitigate the risk of significant morbidity, while also comparing encephalitis induced by immunotherapy with that caused by traditional chemotherapies and targeted oncologic treatments.

Therapeutic antibodies in oncology: an immunopharmacological overview

The biotechnological development of monoclonal antibodies and their immunotherapeutic use in oncology have grown exponentially in the last decade, becoming the first-line therapy for some types of cancer. Their mechanism of action is based on the ability to regulate the immune system or by interacting with targets that are either overexpressed in tumor cells, released into the extracellular milieu or involved in processes that favor tumor growth. In addition, the intrinsic characteristics of each subclass of antibodies provide specific effector functions against the tumor by activating antibody-dependent cellular cytotoxicity, complement-dependent cytotoxicity, and antibody-dependent cellular phagocytosis, among other mechanisms. The rational design and engineering of monoclonal antibodies have improved their pharmacokinetic and pharmacodynamic features, thus optimizing the therapeutic regimens administered to cancer patients and improving their clinical outcomes. The selection of the immunoglobulin G subclass, modifications to its crystallizable region (Fc), and conjugation of radioactive substances or antineoplastic drugs may all improve the antitumor effects of therapeutic antibodies. This review aims to provide insights into the immunological and pharmacological aspects of therapeutic antibodies used in oncology, with a rational approach at molecular modifications that can be introduced into these biological tools, improving their efficacy in the treatment of cancer.

Polymeric PD1/PDL1 bispecific antibody enhances immune checkpoint blockade therapy

Immune checkpoint blockade (ICB) therapy, particularly PD1/PDL1 inhibition, has demonstrated success in bolstering durable responses in patients. However, the response rate remains below 30 %. In this study, we developed a polymeric bispecific antibody (BsAb) targeting PD1/PDL1 to enhance ICB therapy. Specifically, poly(L-glutamic acid) (PGLU) was conjugated with a double cyclic Fc binding peptide, Fc-III-4C, through condensation reactions between the -COOH group of PGLU and the -NH2 group of Fc-III-4C. This conjugate was then mixed with αPD1 and αPDL1 monoclonal antibodies (mAbs) in an aqueous solution. Mechanistically, the PD1/PDL1 BsAb (BsAbαPD1+αPDL1) acts as a bridge between tumor cells and CD8+ T cells, continuously activating CD8+ T cells to a greater extent. This leads to significantly suppressed tumor growth and prolonged survival in a mouse model of colon cancer compared to treatment with either a single mAb or a mixture of free mAbs. The tumor suppression rate achieved by the BsAbαPD1+αPDL1 was 90.1 %, with a corresponding survival rate of 83.3 % after 48 days. Thus, this study underscores the effectiveness of the BsAbαPD1+αPDL1 as a synchronizing T cell engager and dual ICBs, offering theoretical guidance for clinical ICB therapy.

Mosunetuzumab for the treatment of follicular lymphoma

INTRODUCTION

Follicular lymphoma (FL) is an indolent non-Hodgkin lymphoma that shows a progressive increase in relapses and refractory in its natural history and a median survival of approximately 18-20 years. The advent of anti-CD20 monoclonal antibodies has changed the FL therapeutic algorithm, with an increase in progression-free survival. T-cell-dependent bispecific antibodies (BsAbs) represent an emerging drug class against FL.

AREAS COVERED

In this review, we selected papers from the principal databases (PubMed, Medline, Medscape, ASCO, ESMO) between January 2021 and June 2024, using the keywords 'mosunetuzumab' and 'follicular lymphoma' to provide an overview of mosunetuzumab-axgb, a pioneering BsAb. Its mechanism of action, efficacy, safety, and future perspectives were analyzed.

EXPERT OPINION

Mosunetuzumab grants a directing T-cell mediated cytotoxicity and allows a step-up dosing that reduces adverse events, such as cytokine release syndrome, with promising tolerability. At the same time, it improves outcomes in the evolving landscape of FL management, even in post-CAR-T FL patients. Prognostic factors and targetable mechanisms of resistance need to be explored.

Cytokine Biopharmaceuticals with "Activity-on-Demand" for Cancer Therapy

Cytokines are small proteins that modulate the activity of the immune system. Because of their potent immunomodulatory properties, some recombinant cytokines have undergone clinical development and have gained marketing authorization for the therapy of certain forms of cancer. Recombinant cytokines are typically administered at ultralow doses, as many of them can cause substantial toxicity even at submilligram quantities. In an attempt to increase the therapeutic index, fusion proteins based on tumor-homing antibodies (also called "immunocytokines") have been considered, and some products in this class have reached late-stage clinical trials. While antibody-cytokine fusions, which preferentially localize in the neoplastic mass, can activate tumor-resident leukocytes and may be more efficacious than their nontargeted counterparts, such products typically conserve an intact cytokine activity, which may prevent escalation to curative doses. To further improve tolerability, several strategies have been conceived for the development of antibody-cytokine fusions with "activity-on-demand", acting on tumors but helping spare normal tissues from undesired toxicity. In this article, we have reviewed some of the most promising strategies, outlining their potential as well as possible limitations.

Effective treatment of relapsed/refractory CD19-positive B/T-type mixed-phenotype acute leukemia with blinatumomab: A case report

A 26-year-old man was diagnosed with B/T-type mixed-phenotype acute leukemia (MPAL-B/T) based on blasts being positive for CD19, cytoplasmic CD3, and cyCD79a, but negative for myeloperoxidase. Acute lymphoblastic leukemia-based chemotherapy was started, but the leukemia was refractory. He underwent cord blood transplantation with the conditioning regimen of total body irradiation plus cyclophosphamide and cytarabine with granulocyte-colony stimulating factor priming. Prophylaxis for graft versus host disease was performed with short-term methotrexate and cyclosporin. The leukemia relapsed in bone marrow 20 months later. At that time, he was treated with inotuzumab ozogamicin because the blasts expressed CD22 (75.4%), but this was ineffective. He was next administered blinatumomab with dexamethasone pretreatment, resulting in a complete remission (CR). He subsequently underwent human leukocyte antigen-haploidentical peripheral blood stem cell transplantation. He has still maintained a CR for 12 months. Blinatumomab might be a promising treatment and a bridge to stem cell transplantation even in relapsed/refractory CD19-expressing MPAL-B/T.

Stepping forward: T-cell redirecting bispecific antibodies in cancer therapy

T cell-redirecting bispecific antibodies are specifically designed to bind to tumor-associated antigens, thereby engaging with CD3 on the T cell receptor. This linkage between tumor cells and T cells actively triggers T cell activation and initiates targeted killing of the identified tumor cells. These antibodies have emerged as one of the most promising avenues within tumor immunotherapy. However, despite success in treating hematological malignancies, significant advancements in solid tumors have yet to be explored. In this review, we aim to address the critical challenges associated with T cell-redirecting bispecific antibodies and explore novel strategies to overcome these obstacles, with the ultimate goal of expanding the application of this therapy to include solid tumors.

T-Cell Engagers-The Structure and Functional Principle and Application in Hematological Malignancies

Recent advancements in cancer immunotherapy have made directing the cellular immune response onto cancer cells a promising strategy for the treatment of hematological malignancies. The introduction of monoclonal antibody-based (mAbs) targeted therapy has significantly improved the prognosis for hematological patients. Facing the issues of mAb-based therapies, a novel bispecific antibody (BsAb) format was developed. T-cell engagers (TCEs) are BsAbs, which simultaneously target tumor-associated antigens on tumor cells and CD3 molecules present on T-cells. This mechanism allows for the direct activation of T-cells and their anti-tumor features, ultimately resulting in the lysis of tumor cells. In 2014, the FDA approved blinatumomab, a TCE directed to CD3 and CD19 for treatment of acute lymphoblastic leukemia. Since then, numerous TCEs have been developed, allowing for treating different hematological malignancies such as acute myeloid leukemia, multiple myeloma, and non-Hodgkin lymphoma and Hodgkin lymphoma. As of November 2023, seven clinically approved TCE therapies are on the market. TCE-based therapies still have their limitations; however, improving the properties of TCEs, as well as combining TCE-based therapies with other forms of treatment, give hope to find the cures for currently terminal diseases. In this paper, we summarized the technical basis of the TCE technology, its application in hematology, and its current issues and prospects.

A Novel Dual-Fc Bispecific Antibody with Enhanced Fc Effector Function

Bispecific antibodies (BsAbs) are undergoing continued development for applications in oncology and autoimmune diseases. While increasing activity by having more than one targeting arm, most BsAb engineering employs single Fc engagement as monoclonal antibodies. Here, we designed a novel immunoglobulin gamma-1 (IgG1)-derived dual-Fc BsAb containing two Fc regions and two distinct asymmetric antigen binding arms comprising a Fab arm and another VHH domain. In conjunction with the knob-into-hole technology, dual-Fc BsAbs could be produced with a high yield and good stability. We explore how Fc engineering effects on dual-Fc constructs could boost the desired therapeutic efficacy. This new format enabled simultaneous bispecific binding to corresponding antigens. Furthermore, compared to the one-Fc control molecules, dual-Fc BsAbs were shown to increase the avidity-based binding to FcγRs to result in higher ADCC and ADCP activities by potent avidity via binding to two antigens and Fc receptors. Overall, this novel BsAb format with enhanced effector functionalities provides a new option for antibody-based immunotherapy.

T Cell Receptor-Directed Bispecific T Cell Engager Targeting MHC-Linked NY-ESO-1 for Tumor Immunotherapy

Antibody-based bispecific T cell engagers (TCEs) that redirect T cells to kill tumor cells have shown a promising therapeutic effect on hematologic malignancies. However, tumor-specific targeting is still a challenge for TCEs, impeding the development of TCEs for solid tumor therapy. The major histocompatibility complex (MHC) presents almost all intracellular peptides (including tumor-specific peptides) on the cell surface to be scanned by the TCR on T cells. With the premise of choosing optimal peptides, the final complex peptide-MHC could be the tumor-specific target for TCEs. Here, a novel TCR-directed format of a TCE targeting peptide-MHC was designed named IgG-T-TCE, which was modified from the IgG backbone and prepared in a mammalian cell expression system. The recombinant IgG-T-TCE-NY targeting NY-ESO-1157-165/HLA-A*02:01 could be generated in HEK293 cells with a glycosylated TCR and showed potency in T cell activation and redirecting T cells to specifically kill target tumor cells. We also found that the in vitro activity of IgG-T-TCE-NY could be leveraged by various anti-CD3 antibodies and Fc silencing. The IgG-T-TCE-NY efficiently inhibited tumor growth in a tumor-PBMC co-engrafted mouse model without any obvious toxicities.

Pneumocystis jirovecii Pneumonia Secondary to Blinatumomab Therapy: A Case Report

INTRODUCTION

With the increasing use of blinatumomab in relapsed or refractory B-cell precursor acute lymphoblastic leukemia (ALL), including minimal residual disease (MRD)-positive cases, awareness of its adverse effects has gradually improved. Pneumocystis jirovecii pneumonia (PCP) associated with blinatumomab therapy is rare.

CASE PRESENTATION

We present a case of PCP in a patient undergoing blinatumomab therapy. A 70-year-old female diagnosed with Philadelphia-like CRLF2 overexpression B-cell precursor ALL received blinatumomab as consolidation therapy after achieving complete remission with prior induction chemotherapy. On the second day of blinatumomab infusion, she developed intermittent low-grade fever, and chest computed tomography (CT) revealed subtle infiltrates and nodules. Despite empiric trimethoprim-sulfamethoxazole (TMP-SMX) prophylaxis, she progressed to significant shortness of breath and type I respiratory failure, with increased lactate dehydrogenase and β-D-glucan assays. Chest CT showed diffuse ground-glass opacities with scattered small nodules. The dry cough prompted next-generation sequencing of peripheral blood, which tested positive for pneumocystis jirovecii without evidence of other pathogens. Consequently, the patient was diagnosed with PCP. The first cycle of blinatumomab had to be discontinued, and therapeutic dosages of TMP-SMX and dexamethasone were administered, resulting in full recovery and stable condition during follow-ups.

CONCLUSION

PCP is rare in B-cell precursor ALL patients receiving blinatumomab therapy but manifests with early onset and rapid disease progression. Despite prophylaxis, PCP infection cannot be ignored during blinatumomab therapy. Therefore, heightened attention is warranted when using blinatumomab therapy.

Drug-Loaded Biomimetic Carriers for Non-Hodgkin's Lymphoma Therapy: Advances and Perspective

Chemotherapy remains the mainstay of treatment for the lymphoma patient population, despite its relatively poor therapeutic results, high toxicity, and low specificity. With the advancement of biotechnology, the significance of drug-loading biomimetic materials in the medical field has become increasingly evident, attracting extensive attention from the scientific community and the pharmaceutical industry. Given that they can cater to the particular requirements of lymphoma patients, drug-loading biomimetic materials have recently become a potent and promising delivery approach for various applications. This review mainly reviews the recent advancements in the treatment of tumors with biological drug carrier-loaded drugs, outlines the mechanisms of lymphoma development and the diverse treatment modalities currently available, and discusses the merits and limitations of biological drug carriers. What is more, the practical application of biocarriers in tumors is explored by providing examples, and the possibility of loading such organisms with antilymphoma drugs for the treatment of lymphoma is conceived.

Myeloid and dendritic cells enhance therapeutics-induced cytokine release syndrome features in humanized BRGSF-HIS preclinical model

Objectives

Despite their efficacy, some immunotherapies have been shown to induce immune-related adverse events, including the potentially life-threatening cytokine release syndrome (CRS), calling for reliable and translational preclinical models to predict potential safety issues and investigate their rescue. Here, we tested the reliability of humanized BRGSF mice for the assessment of therapeutics-induced CRS features in preclinical settings.

Methods

BRGSF mice reconstituted with human umbilical cord blood CD34+ cells (BRGSF-CBC) were injected with anti-CD3 antibody (OKT3), anti-CD3/CD19 bispecific T-cell engager Blinatumomab, or VISTA-targeting antibody. Human myeloid and dendritic cells' contribution was investigated in hFlt3L-boosted BRGSF-CBC mice. OKT3 treatment was also tested in human PBMC-reconstituted BRGSF mice (BRGSF-PBMC). Cytokine release, immune cell distribution, and clinical signs were followed.

Results

OKT3 injection in BRGSF-CBC mice induced hallmark features of CRS, specifically inflammatory cytokines release, modifications of immune cell distribution and activation, body weight loss, and temperature drop. hFlt3L-boosted BRGSF-CBC mice displayed enhanced CRS features, revealing a significant role of myeloid and dendritic cells in this process. Clinical CRS-managing treatment Infliximab efficiently attenuated OKT3-induced toxicity. Comparison of OKT3 treatment's effect on BRGSF-CBC and BRGSF-PBMC mice showed broadened CRS features in BRGSF-CBC mice. CRS-associated features were also observed in hFlt3L-boosted BRGSF-CBC mice upon treatment with other T-cell or myeloid-targeting compounds.

Conclusions

These data show that BRGSF-CBC mice represent a relevant model for the preclinical assessment of CRS and CRS-managing therapies. They also confirm a significant role of myeloid and dendritic cells in CRS development and exhibit the versatility of this model for therapeutics-induced safety assessment.

Bispecific antibodies in indolent B-cell lymphomas

The advent of immunotherapy in lymphomas, beginning with Rituximab, have led to paradigm shifting treatments that are increasingly bringing a greater number of affected patients within the ambit of durable disease control and cure. Bispecific antibodies harness the properties of the immunoglobulin antibody structure to design molecules which, apart from engaging with the target tumour associated antigen, engage the host's T-cells to cause tumour cell death. Mosunetuzumab, an anti-CD20 directed bispecific antibody was the first to be approved in follicular lymphoma, this has now been followed by quick approvals of Glofitamab and Epcoritamab in diffuse large B-cell lymphomas. This article reviews contemporary data and ongoing studies evaluating the role of bispecific antibodies in indolent b-cell non Hodgkin lymphomas. This is an area of active research and presents many opportunities in advancing the treatment of indolent lymphomas and potentially forge a chemo-free treatment paradigm in this condition.

[Blinatumomab as bridging therapy in two children with B-cell acute lymphoblastic leukemia complicated by invasive fungal disease]

This article reports two cases of children with B-cell acute lymphoblastic leukemia (B-ALL) complicated by invasive fungal disease (IFD) who received bridging treatment using blinatumomab. Case 1 was a 4-month-old female infant who experienced recurrent high fever and limb weakness during chemotherapy. Blood culture was negative, and next-generation sequencing (NGS) of peripheral blood, bronchoalveolar lavage fluid, and cerebrospinal fluid were all negative. Chest CT and cranial MRI revealed obvious infection foci. Case 2 was a 2-year-old male patient who experienced recurrent high fever with multiple inflammatory masses during chemotherapy. Candida tropicalis was detected in peripheral blood and abscess fluid using NGS, while blood culture and imaging examinations showed no obvious abnormalities. After antifungal and blinatumomab therapy, both cases showed significant improvement in symptoms, signs, and imaging, and B-ALL remained in continuous remission. The report indicates that bridging treatment with blinatumomab in children with B-ALL complicated by IFD can rebuild the immune system and control the underlying disease in the presence of immunosuppression and severe fungal infection.

Forks in the road for CAR T and CAR NK cell cancer therapies

The advent of chimeric antigen receptor (CAR) T cell therapy has resulted in unprecedented long-term clearance of relapse/refractory hematological malignancies in both pediatric and adult patients. However, severe toxicities, such as cytokine release syndrome and neurotoxicity, associated with CAR T cells affect therapeutic utility; and treatment efficacies for solid tumors are still not impressive. As a result, engineering strategies that modify other immune cell types, especially natural killer (NK) cells have arisen. Owing to both CAR-dependent and CAR-independent (innate immune-mediated) antitumor killing capacity, major histocompatibility complex-independent cytotoxicity, reduced risk of alloreactivity and lack of major CAR T cell toxicities, CAR NK cells constitute one of the promising next-generation CAR immune cells that are also amenable as 'off-the-shelf' therapeutics. In this Review, we compare CAR T and CAR NK cell therapies, with particular focus on immunological synapses, engineering strategies and challenges.

Small Antibodies with Big Applications: Nanobody-Based Cancer Diagnostics and Therapeutics

Monoclonal antibodies (mAbs) have exhibited substantial potential as targeted therapeutics in cancer treatment due to their precise antigen-binding specificity. Despite their success in tumor-targeted therapies, their effectiveness is hindered by their large size and limited tissue permeability. Camelid-derived single-domain antibodies, also known as nanobodies, represent the smallest naturally occurring antibody fragments. Nanobodies offer distinct advantages over traditional mAbs, including their smaller size, high stability, lower manufacturing costs, and deeper tissue penetration capabilities. They have demonstrated significant roles as both diagnostic and therapeutic tools in cancer research and are also considered as the next generation of antibody drugs. In this review, our objective is to provide readers with insights into the development and various applications of nanobodies in the field of cancer treatment, along with an exploration of the challenges and strategies for their prospective clinical trials.

Anti-CD19/CD8 bispecific T cell engager for the potential treatment of B cell malignancies

The administration of blinatumomab was accompanied by several adverse effects, including activation of regulatory T-cells and cytokine storm. The objective of this study was to produce and evaluate a novel αCD8/CD19 BiTE (αCD8/CD19) with the potency to directly target CD8+T-cells. In-silico studies were utilized for determining proper folding, receptor binding, and structural stability of αCD8/CD19 protein. Western blotting and indirect surface staining were used to evaluate the size accuracy and binding potency of the purified protein. Functionality was assessed for granzyme B production, cytotoxicity, and proliferation. TheαCD8/CD19recombinant protein was produced in the CHO-K1 cell line with a final concentration of 1.94 mg/l. The αCD8/CD19 bound to CD8+and CD19+cell lines and induced significant granzyme B production, cytotoxic activity and proliferation potential in the presence of IL-2 and tumor target cells. The maximum CD8+T-cell biological activity was observed on the 10th day with 10:1 effector-to-target ratio.

A PD-L1xCD3 bispecific nanobody as a novel T-cell engager in treating PD-L1 overexpression melanoma

The development of Immune checkpoint blockade(ICB) therapy and BRAF- and MEK-targeted therapies has reshaped the survival outcomes of the patients with advanced melanoma. PD-1/PD-L1 blockade was an approved strategy in melanoma treatment. Here we design a PD-L1 xCD3 nanobody as a novel bispecific T cell engager (BiTE) in treating PD-L1 overexpression melanoma. BiTE PD-L1×CD3 Nb was predicted to bind near a large acidic surface on CD3-ε similar to UCHT1-scFv antibody based on alpha-fold and molecular docking. BiTE PD-L1×CD3 Nb and anti-CD3 Nb retained the ability to activate T cells to produce TNF-α and IFN-γ in a dose-dependent manner. The IC50 value of BiTE PD-L1×CD3 Nb was 4.208μg/mL. BiTE PD-L1×CD3 Nb showed obvious cytotoxic activity on both A375WT and A375PD-L1 related to PD-L1 expression level.

Updates on lymphoblastic leukemia/lymphoma classification and minimal/measurable residual disease analysis

Lymphoblastic leukemia/lymphoma (ALL/LBL), especially certain subtypes, continues to confer morbidity and mortality despite significant therapeutic advances. The pathologic classification of ALL/LBL, especially that of B-ALL, has recently substantially expanded with the identification of several distinct and prognostically important genetic drivers. These discoveries are reflected in both current classification systems, the World Health Organization (WHO) 5th edition and the new International Consensus Classification (ICC). In this article, novel subtypes of B-ALL are reviewed, including DUX4, MEF2D and ZNF384-rearranged B-ALL; the rare pediatric entity B-ALL with TLF3::HLF, now added to the classifications, is discussed; updates to the category of B-ALL with BCR::ABL1-like features (Ph-like B-ALL) are summarized; and emerging genetic subtypes of T-ALL are presented. The second half of the article details current approaches to minimal/measurable residual disease (MRD) detection in B-ALL and T-ALL and presents anticipated challenges to current approaches in the burgeoning era of antigen-directed immunotherapy.

Identification of Mispairing Omic Signatures in Chinese Hamster Ovary (CHO) Cells Producing a Tri-Specific Antibody

Monoclonal antibody-based therapy has shown efficacy against cancer, autoimmune, infectious, and inflammatory diseases. Multispecific antibodies (MsAbs), including trispecifics (tsAbs), offer enhanced therapeutic potential by targeting different epitopes. However, when co-expressed from three or more different polypeptide chains, MsAb production can lead to incorrect chain assembly and co-production of mispaired species with impaired biological activity. Moreover, mispairing carries significant challenges for downstream purification, decreasing yields and increasing the cost of bioprocess development. In this study, quantitative transcriptomics and proteomics analyses were employed to investigate which signaling pathways correlated with low and high mispairing clone signatures. Gene and protein expression profiles of Chinese hamster ovary (CHO) clones producing an tsAb were analyzed in the exponential growth and stationary (tsAb production) phase of fed-batch culture. Functional analysis revealed activated endoplasmic reticulum stress in high mispairing clones in both culture phases, while low mispairing clones exhibited expression profiles indicative of activated protein translation, as well as higher endocytosis and target protein degradation, suggesting the clearance of unfolded proteins through ubiquitin-mediated mechanisms. In addition, through transcriptomic profiling, we identified a group of genes that have the potential to be used as a biomarker panel tool for identifying high mispairing levels in the early stages of bioprocess development.

Bispecific antibodies in cancer therapy: Target selection and regulatory requirements

In recent years, the development of bispecific antibodies (bsAbs) has been rapid, with many new structures and target combinations being created. The boom in bsAbs has led to the successive issuance of industry guidance for their development in the US and China. However, there is a high degree of similarity in target selection, which could affect the development of diversity in bsAbs. This review presents a classification of various bsAbs for cancer therapy based on structure and target selection and examines the advantages of bsAbs over monoclonal antibodies (mAbs). Through database research, we have identified the preferences of available bsAbs combinations, suggesting rational target selection options and warning of potential wastage of medical resources. We have also compared the US and Chinese guidelines for bsAbs in order to provide a reference for their development.

CLN-978, a novel half-life extended CD19/CD3/HSA-specific T cell-engaging antibody construct with potent activity against B-cell malignancies with low CD19 expression

BACKGROUND

Despite significant progress in the development of T cell-engaging therapies for various B-cell malignancies, a high medical need remains for the refractory disease setting, often characterized by suboptimal target levels.

METHODS

To address this issue, we have developed a 65-kDa multispecific antibody construct, CLN-978, with affinities tuned to optimize the killing of low-CD19 expressing tumor cells. CLN-978 bound to CD19 on B cells with picomolar affinity, and to CD3ε on T cells with nanomolar affinity. A serum albumin binding domain was incorporated to extend serum half-life. In this setting, we biophysically characterize and report the activities of CLN-978 in cell co-culture assays, multiple mouse models and non-human primates.

RESULTS

Human T cells redirected by CLN-978 could eliminate target cells expressing less than 300 copies of CD19 on their surface. The half-life extension and high affinity for CD19 led to significant antitumor activity in murine lymphoma models at very low doses of CLN-978. In primates, we observed a long serum half-life, deep and sustained depletion of normal B cells, and remarkable tolerability, in particular, reduced cytokine release when CLN-978 was administered subcutaneously.

CONCLUSIONS

CLN-978 warrants further exploration. An ongoing clinical phase 1 trial is investigating safety, pharmacokinetics, pharmacodynamics, and the initial therapeutic potential of subcutaneously administered CLN-978 in patients with non-Hodgkin's lymphoma.

Harnessing the Immune System: An Effective Way to Manage Diffuse Large B-Cell Lymphoma

Diffuse large B-cell lymphoma (DLBCL) is a heterogenous hematological disorder with malignant potential controlled by immunological characteristics of the tumor microenvironment. Rapid breakthrough in the molecular pathways has made immunological approaches the main anchor in the management of DLBCL, with or without chemotherapeutic agents. Rituximab was the first monoclonal antibody approved for the treatment of DLBCL. Following rituximab that transformed the therapeutic landscape, other novel immunological agents including chimeric antigen T-cell therapy have reshaped the management of relapsed/refractory DLBCL. However, resistance and refractory state remain a challenge in the management of DLBCL. For this literature review, we screened articles from Medline, Embase, Cochrane databases and the European/North American guidelines from March 2010 through October 2022 for DLBCL. Here we discuss immunological agents that will significantly affect future treatment of this aggressive type of lymphoma.

Bispecific antibody targeting TGF-β and PD-L1 for synergistic cancer immunotherapy

The PD-1/PD-L1 signaling pathway plays a crucial role in cancer immune evasion, and the use of anti-PD-1/PD-L1 antibodies represents a significant milestone in cancer immunotherapy. However, the low response rate observed in unselected patients and the development of therapeutic resistance remain major obstacles to their clinical application. Accumulating studies showed that overexpressed TGF-β is another immunosuppressive factor apart from traditional immune checkpoints. Actually, the effects of PD-1 and TGF-β pathways are independent and interactive, which work together contributing to the immune evasion of cancer cell. It has been verified that blocking TGF-β and PD-L1 simultaneously could enhance the efficacy of PD-L1 monoclonal antibody and overcome its treatment resistance. Based on the bispecific antibody or fusion protein technology, multiple bispecific and bifunctional antibodies have been developed. In the preclinical and clinical studies, these updated antibodies exhibited potent anti-tumor activity, superior to anti-PD-1/PD-L1 monotherapies. In the review, we summarized the advances of bispecific antibodies targeting TGF-β and PD-L1 in cancer immunotherapy. We believe these next-generation immune checkpoint inhibitors would substantially alter the cancer treatment paradigm, especially in anti-PD-1/PD-L1-resistant patients.

Recombinant Human CD19 in CHO-K1 Cells: Glycosylation Patterns as a Quality Attribute of High Yield Processes

CD19 is an essential protein in personalized CD19-targeting chimeric antigen receptor (CAR)-T cell-based cancer immunotherapies and CAR-T cell functionality evaluation. However, the recombinant expression of this "difficult to-express" (DTE) protein is challenging, and therefore, commercial access to the protein is limited. We have previously described the successful stable expression of our soluble CD19-AD2 fusion protein of the CD19 extracellular part fused with human serum albumin domain 2 (AD2) in CHO-K1 cells. The function, stability, and secretion rate of DTE proteins can be improved by culture conditions, such as reduced temperature and a shorter residence time. Moreover, glycosylation, as one of the most important post-translational modifications, represents a critical quality attribute potentially affecting CAR-T cell effector function and thus impacting therapy's success. In this study, we increased the production rate of CD19-AD2 by 3.5-fold through applying hypothermic culture conditions. We efficiently improved the purification of our his-tagged CD19-AD2 fusion protein via a Ni-NTA-based affinity column using a stepwise increase in the imidazole concentration. The binding affinity to commercially available anti-CD19 antibodies was evaluated via Bio-Layer Interferometry (BLI). Furthermore, we revealed glycosylation patterns via Electrospray Ionization Mass Spectrometry (ESI-MS), and five highly sialylated and multi-antennary N-glycosylation sites were identified. In summary, we optimized the CD19-AD2 production and purification process and were the first to characterize five highly complex N-glycosylation sites.

CAR T Cell Therapy: Remedies of Current Challenges in Design, Injection, Infiltration and Working

Chimeric antigen receptor (CAR) T cell therapy, as an innovative immunotherapy, plays a huge role in current cancer therapy. Although CAR T cell therapy has demonstrated therapeutic effects in some subtypes of B cell leukemia or lymphoma, there are many challenges that limit the therapeutic efficacy of CAR T cells in solid tumors. And how to efficiently transport CAR T cells to tumor tissues is a continuing concern for us. In this review, experiments have been extensively studied and compared. We finally compared the influence of different injection methods on therapeutic efficacy. We also carefully explored the difficulties of designing, homing, and working of CAR T cells, and ultimately came up with better solutions for each process to help CAR T cells reach tumor tissue more efficiently and quickly. These results will have significant implications for guiding CAR T cell therapy in cancer treatment.

Simultaneous evaluation of treatment efficacy and toxicity for bispecific T-cell engager therapeutics in a humanized mouse model

Immuno-oncology (IO)-based therapies such as checkpoint inhibitors, bi-specific antibodies, and CAR-T-cell therapies have shown significant success in the treatment of several cancer indications. However, these therapies can result in the development of severe adverse events, including cytokine release syndrome (CRS). Currently, there is a paucity of in vivo models that can evaluate dose-response relationships for both tumor control and CRS-related safety issues. We tested an in vivo PBMC humanized mouse model to assess both treatment efficacy against specific tumors and the concurrent cytokine release profiles for individual human donors after treatment with a CD19xCD3 bispecific T-cell engager (BiTE). Using this model, we evaluated tumor burden, T-cell activation, and cytokine release in response to bispecific T-cell-engaging antibody in humanized mice generated with different PBMC donors. The results show that PBMC engrafted NOD-scid Il2rgnull mice lacking expression of mouse MHC class I and II (NSG-MHC-DKO mice) and implanted with a tumor xenograft predict both efficacy for tumor control by CD19xCD3 BiTE and stimulated cytokine release. Moreover, our findings indicate that this PBMC-engrafted model captures variability among donors for tumor control and cytokine release following treatment. Tumor control and cytokine release were reproducible for the same PBMC donor in separate experiments. The PBMC humanized mouse model described here is a sensitive and reproducible platform that identifies specific patient/cancer/therapy combinations for treatment efficacy and development of complications.

Diagnostic Flow Cytometry in the Era of Targeted Therapies: Lessons from Therapeutic Monoclonal Antibodies and Chimeric Antigen Receptor T-cell Adoptive Immunotherapy

Therapeutic monoclonal antibodies (therapeutic mAb) and adoptive immunotherapy have become increasingly more common in the treatment of hematolymphoid neoplasms, with practical implications for diagnostic flow cytometry. Their use can reduce the sensitivity of flow cytometry for populations of interest owing to downregulation/loss of the target antigen, competition for the target antigen, or lineage switch. Expanded flow panels, marker redundancy, and exhaustive gating strategies can overcome this limitation. Therapeutic mAb have been reported to cause pseudo-light chain restriction, and awareness of this potential artifact is key. Established guidelines do not yet exist for antigen expression by flow cytometry for therapeutic purposes.

Treatment of Relapsed B/T-cell Mixed Phenotype Acute Leukemia With Blinatumomab

Here, we describe the treatment of a patient with relapsed/refractory B/T mixed phenotype acute leukemia (MPAL) using blinatumomab monotherapy, the first bispecific T cell engager (BiTE) approved by the FDA for relapsed/refractory B cell acute lymphoblastic leukemia (B-ALL). A 64-year-old man with a history of stage 3 chronic kidney disease and type 2 diabetes mellitus was discovered to have B/T MPAL on bone marrow biopsy during hospitalization for dyspnea due to pulmonary embolism. The patient achieved brief remission with blinatumomab treatment before succumbing to neutropenic sepsis. The lack of sufficient data to guide therapy in MPAL remains a challenge, highlighting the potential of new targeted approaches such as blinatumomab to improve outcomes in relapsed/refractory MPAL.

Adeno-Associated Virus-Mediated Immunotherapy Based on Bispecific Tandem scFv for Alzheimer’s Disease

Background: Patients with Alzheimer’s disease (AD) have considerably increased globally as a result of population aging, placing a significant burden on the global economy and the medical system. The outcome of clinical trials for AD immunotherapy that solely targeted amyloid-β (Aβ) or phosphorylated tau protein (p-Tau) was unsatisfactory. Therefore, blocking both Aβ and p-Tau’s pathological processes simultaneously while also preventing their interaction may be the key to developing an effective AD therapy. Objective: To develop a novel immunotherapy based on bispecific tandem scFv (TaFv) against AD. Methods: Bispecific single-chain antibody that targets both Aβ and p-Tau were obtained using E. coli expression system. Biological ability of TaFvs were determined by ELISA, SDS-PAGE, and immunohistochemical assay. Recombinant adeno-associated virus 9 (rAAV9) were packaged to create TaFv. The in vivo activity of rAAV9 were detected in mouse, using biophotonic imaging and frozen section methods. Results: The outcomes demonstrated that both Aβ and p-Tau had a high affinity for the bispecific TaFv. Additionally, it can bind to the amyloid plaques and neuronal tangles in the brain slices of an AD mouse model. Moreover, the rAAV9 could infect neuronal cells, transverse the blood-brain barrier, and express TaFv in the mouse brain. Conclusion: This novel immunotherapy offers a fresh concept for the immunotherapy of AD and successfully delivers the double target antibody into the brain, acting on both pathogenic substances Aβ and p-Tau.

Antibody-drug conjugates and bispecific antibodies targeting cancers: applications of click chemistry

Engineering approaches using antibody drug conjugates (ADCs) and bispecific antibodies (bsAbs) are designed to overcome the limitations of conventional chemotherapies and therapeutic antibodies such as drug resistance and non-specific toxicity. Cancer immunotherapies have been shown to be clinically successful with checkpoint blockade and chimeric antigen receptor T cell therapy; however, overactive immune systems still represent a major problem. Given the complexity of a tumor environment, it would be advantageous to have a strategy targeting two or more molecules. We highlight the necessity and importance of a multi-target platform strategy against cancer. Approximately 400 ADCs and over 200 bsAbs are currently being clinically developed for several indications, with promising signs of therapeutic activity. ADCs include antibodies that recognize tumor antigens, linkers that stably connect drugs, and powerful cytotoxic drugs, also known as payloads. ADCs have direct therapeutic effects by targeting cancers with a strong payload. Another type of drug that uses antibodies are bsAbs, targeting two antigens by linking to antigen recognition sites or bridging cytotoxic immune cells to tumor cells, resulting in cancer immunotherapy. Three bsAbs and one ADC have been approved for use by the FDA and the EMA in 2022. Among these, two of the bsAbs and the one ADC are used for cancers. We introduced that bsADC, a combination of ADC and bsAbs, has yet to be approved and several candidates are in the early stages of clinical development in this review. bsADCs technology helps increase the specificity of ADCs or the internalization and killing ability of bsAbs. We also briefly discuss the application of click chemistry in the efficient development of ADCs and bsAbs as a conjugation strategy. The present review summarizes the ADCs, bsAbs, and bsADCs that have been approved for anti-cancer or currently in development. These strategies selectively deliver drugs to malignant tumor cells and can be used as therapeutic approaches for various types of cancer.

Cancer immunotherapies: A hope for the uncurable?

The use of cancer immunotherapies is not novel but has been used over the decades in the clinic. Only recently have we found the true potential of stimulating an anti-tumor response after the breakthrough of checkpoint inhibitors. Cancer immunotherapies have become the first line treatment for many malignancies at various stages. Nevertheless, the clinical results in terms of overall survival and progression free survival were not as anticipated. Majority of cancer patients do not respond to immunotherapies and the reasons differ. Hence, further improvements for cancer immunotherapies are crucially needed. In the review, we will discuss various forms of cancer immunotherapies that are being tested or already in the clinic. Moreover, we also highlight future directions to improve such therapies.

Nanobodies in cell-mediated immunotherapy: On the road to fight cancer

The immune system is essential in recognizing and eliminating tumor cells. The unique characteristics of the tumor microenvironment (TME), such as heterogeneity, reduced blood flow, hypoxia, and acidity, can reduce the efficacy of cell-mediated immunity. The primary goal of cancer immunotherapy is to modify the immune cells or the TME to enable the immune system to eliminate malignancies successfully. Nanobodies, known as single-domain antibodies, are light chain-free antibody fragments produced from Camelidae antibodies. The unique properties of nanobodies, including high stability, reduced immunogenicity, enhanced infiltration into the TME of solid tumors and facile genetic engineering have led to their promising application in cell-mediated immunotherapy. They can promote the cancer therapy either directly by bridging between tumor cells and immune cells and by targeting cancer cells using immune cell-bound nanobodies or indirectly by blocking the inhibitory ligands/receptors. The T-cell activation can be engaged through anti-CD3 and anti-4-1BB nanobodies in the bispecific (bispecific T-cell engagers (BiTEs)) and trispecific (trispecific T-cell engager (TriTEs)) manners. Also, nanobodies can be used as natural killer (NK) cell engagers (BiKEs, TriKEs, and TetraKEs) to create an immune synapse between the tumor and NK cells. Nanobodies can redirect immune cells to attack tumor cells through a chimeric antigen receptor (CAR) incorporating a nanobody against the target antigen. Various cancer antigens have been targeted by nanobody-based CAR-T and CAR-NK cells for treating both hematological and solid malignancies. They can also cause the continuation of immune surveillance against tumor cells by stopping inappropriate inhibition of immune checkpoints. Other roles of nanobodies in cell-mediated cancer immunotherapy include reprogramming macrophages to reduce metastasis and angiogenesis, as well as preventing the severe side effects occurring in cell-mediated immunotherapy. Here, we highlight the critical functions of various immune cells, including T cells, NK cells, and macrophages in the TME, and discuss newly developed immunotherapy methods based on the targeted manipulation of immune cells and TME with nanobodies.

The emerging scenario of immunotherapy for T-cell Acute Lymphoblastic Leukemia: advances, challenges and future perspectives

T-cell acute lymphoblastic leukemia (T-ALL) is a challenging pediatric and adult haematologic disease still associated with an unsatisfactory cure rate. Unlike B-ALL, the availability of novel therapeutic options to definitively improve the life expectancy for relapsed/resistant patients is poor. Indeed, the shared expression of surface targets among normal and neoplastic T-cells still limits the efficacy and may induce fratricide effects, hampering the use of innovative immunotherapeutic strategies. However, novel monoclonal antibodies, bispecific T-cell engagers (BTCEs), and chimeric antigen receptors (CAR) T-cells recently showed encouraging results and some of them are in an advanced stage of pre-clinical development or are currently under investigation in clinical trials. Here, we review this exciting scenario focusing on most relevant advances, challenges, and perspectives of the emerging landscape of immunotherapy of T-cell malignancies.

Impact of Precision Medicine in Oncology: Immuno-oncology

ABSTRACT

Cancer treatment has dramatically changed over the last decade with the development of immunotherapy. Therapies including immune cytokines, immune checkpoint inhibition, intratumoral therapies, and cellular therapies are already widely used in the oncology clinic. Active development continues in these areas and in the development of vaccines, bispecific therapies, and more refined cellular therapies. In this review, we will examine the role that immune therapy has in cancer treatment and explore areas of future development.

Amsacrine combined with etoposide and methylprednisolone is a feasible and safe component in first-line intensified treatment of pediatric patients with high-risk acute lymphoblastic leukemia in CoALL08-09 trial

BACKGROUND

The prognosis of children with acute lymphoblastic leukemia (ALL) has improved considerably over the past five decades. However, to achieve cure in patients with refractory or relapsed disease, novel treatment options are necessary.

METHODS

In the multicenter trial Cooperative Study Group for Childhood Acute Lymphoblastic Leukemia (CoALL)08-09, one additional treatment element consisting of the rarely used chemotherapeutic agent amsacrine combined with etoposide and methylprednisolone (AEP) (amsacrine 2 × 100 mg/m² , etoposide 2 × 500 mg/m² , and methylprednisolone 4 × 1000 mg/m² ) was incorporated into the first-line treatment of pediatric patients with poor treatment responses at the end of induction (EOI), measured by minimal residual disease (MRD). These patients were stratified into a high-risk intensified arm (HR-I), including an AEP element at the end of consolidation. Patients with induction failure (IF), that is, with lack of cytomorphological remission EOI, were eligible for hematopoietic stem cell transplantation (HSCT) after remission had been reached. These patients received AEP as a part of their MRD-guided bridging-to-transplant treatments.

RESULTS

A significant improvement in probability of overall survival (pOS) was noted for the CoALL08-09 HR-I patients compared to MRD-matched patients from the preceding CoALL07-03 trial in the absence of severe or persistent treatment-related toxicities. Relapse rate and probability of event-free survival (pEFS) did not differ significantly between trials. In patients with IF, stable or improved MRD responses after AEP were observed without severe or persistent treatment-related toxicities.

CONCLUSION

In conclusion, AEP is well tolerated as a component of the HR treatment and is useful in bridging-to-transplant settings.

TriTECM: A tetrafunctional T-cell engaging antibody with built-in risk mitigation of cytokine release syndrome

Harnessing the innate power of T cells for therapeutic benefit has seen many shortcomings due to cytotoxicity in the past, but still remains a very attractive mechanism of action for immune-modulating biotherapeutics. With the intent of expanding the therapeutic window for T-cell targeting biotherapeutics, we present an attenuated trispecific T-cell engager (TCE) combined with an anti- interleukin 6 receptor (IL-6R) binding moiety in order to modulate cytokine activity (TriTECM). Overshooting cytokine release, culminating in cytokine release syndrome (CRS), is one of the severest adverse effects observed with T-cell immunotherapies, where the IL-6/IL-6R axis is known to play a pivotal role. By targeting two tumour-associated antigens, epidermal growth factor receptor (EGFR) and programmed death ligand 1 (PD-L1), simultaneously with a bispecific two-in-one antibody, high tumour selectivity together with checkpoint inhibition was achieved. We generated tetrafunctional molecules that contained additional CD3- and IL-6R-binding modules. Ligand competition for both PD-L1 and IL-6R as well as inhibition of both EGF- and IL-6-mediated signalling pathways was observed. Furthermore, TriTECM molecules were able to activate T cells and trigger T-cell-mediated cytotoxicity through CD3-binding in an attenuated fashion. A decrease in pro-inflammatory cytokine interferon γ (IFNγ) after T-cell activation was observed for the TriTECM molecules compared to their respective controls lacking IL-6R binding, hinting at a successful attenuation and potential modulation via IL-6R. As IL-6 is a key player in cytokine release syndrome as well as being implicated in enhancing tumour progression, such molecule designs could reduce side effects and cytotoxicity observed with previous TCEs and widen their therapeutic windows.

Treatment Landscape of Relapsed/Refractory Mantle Cell Lymphoma: An Updated Review

Mantle cell lymphoma (MCL) accounts for nearly 2-6% of all non-Hodgkin lymphoma (NHL) cases, with a steady incidence increase over the past few decades. Although many patients achieve an adequate response to the upfront treatment, the short duration of remission with rapid relapse is challenging during MCL management. In this regard, there is no consensus on the best treatment options for relapsed/refractory (R/R) disease, and the international guidelines demonstrate wide variations in the recommended approaches. The last decade has witnessed the introduction of new agents in the treatment landscape of R/R MCL. Since the introduction of Bruton's tyrosine kinase (BTK) inhibitors, the treatment algorithm and response of R/R MCL patients have dramatically changed. Nevertheless, BTK resistance is common, necessitating further investigations to develop novel agents with a more durable response. Novel agents targeting the B-cell receptor (BCR) signaling have exhibited clinical activity and a well-tolerable safety profile. However, as the responses to these novel agents are still modest in most clinical trials, combination strategies were investigated in pre-clinical and early clinical settings to determine whether the combination of novel agents would exhibit a better durable response than single agents. In this report, we provide an updated literature review that covers recent clinical data about the safety and efficacy of novel therapies for the management of R/R MCL.

A novel CD19/CD22/CD3 trispecific antibody enhances therapeutic efficacy and overcomes immune escape against B-ALL

The bispecific T-cell engager (BiTE) blinatumomab against CD19 and CD3 has emerged as the most successful bispecific antibody (bsAb) to date; however, a significant proportion of patients do not respond to the treatments or eventually experience relapse after an initial response, and the recurrence rate increases significantly due to escape or downregulation of the CD19 antigen. To enhance antitumor efficacy and overcome potential immune escape, we developed a novel approach to design a CD19/CD22/CD3 trispecific antibody (tsAb) by site-specifically fusing anti-CD19 scFv (FMC63) and anti-CD22 nanobody (Nb25) to the defined sites of the CD3 antigen-binding fragment (Fab, SP34). This strategy allows for the optimal formation of immune synapses mediated by CD19/CD22/CD3 between target cells and T cells. Optimized tsAb can be superior for inducing T-cell-specific cytotoxicity and cytokine production against CD19+ and/or CD22+ tumor cells compared to other tsAb formats, and demonstrated significantly enhanced antitumor efficacy and the ability to overcome immune escape compared with the corresponding bsAbs alone or in combination, as well as with blinatumomab. In addition, tsAb treatment can lead to the long-term elimination of primary B-ALL patient samples in the PDX model and significantly prolong survival. This novel approach provides unique insight into the structural optimization of T-cell-redirected multispecific antibodies using site-specific recombination, and may be broadly applicable to heterogeneous and resistant tumor populations as well as solid tumors.

Immunotherapeutic progress and application of bispecific antibody in cancer

Bispecific antibodies (bsAbs) are artificial antibodies with two distinct antigen-binding sites that can bind to different antigens or different epitopes on the same antigen. Based on a variety of technology platforms currently developed, bsAbs can exhibit different formats and mechanisms of action. The upgrading of antibody technology has promoted the development of bsAbs, which has been effectively used in the treatment of tumors. So far, 7 bsAbs have been approved for marketing in the world, and more than 200 bsAbs are in clinical and preclinical research stages. Here, we summarize the development process of bsAbs, application in tumor treatment and look forward to the challenges in future development.

Opportunities and challenges of bi-specific antibodies

The recent clinical approval of different Bi-specific antibodies (BsAbs) has revealed the great therapeutic potential of this novel class of biologicals. For example, the bispecific T-cell engager (BiTE), Blinatumomab, demonstrated the unique capacity of BsAbs to link T-cells with tumor cells, inducing targeted tumor cell removal. Additionally, Amivantamab, recognizing the EGFR and cMet in cis, revealed a substantial improvement of therapeutic efficacy by concomitantly targeting two tumor antigens. Cis-targeting BsAbs furthermore allow discerning cell populations which concurrently express two antigens, for which each antigen expression pattern in itself might not be selective. In this way, BsAbs harbor the great prospect of being more specific and showing fewer side effects than monoclonal antibodies. Nevertheless, BsAbs have also faced major obstacles, for instance, in ensuring reliable assembly and clinical-grade purification. In this review, we summarize the different available antibody platforms currently used for the generation of IgG-like and non-IgG-like BsAbs and explain which approaches have been used to assemble those BsAbs which are currently approved for clinical application. By focusing on the example of regulatory T-cells (Tregs) and the different, ongoing approaches to develop BsAbs specifically targeting Tregs within the tumor microenvironment, our review highlights the huge potential as well as the pitfalls BsAb face in order to emerge as one of the most effective therapeutic biologicals targeting desired cell populations in a highly selective way. Such BsAb may improve treatment efficacy and reduce side effects, thereby opening novel treatment opportunities for a range of different diseases, such as cancer or autoimmune diseases.