Blinatumomab: a historical perspective

Rapid Systematic Screening of Bispecific Antibody Surrogate Geometries for T-Cell Engagement Using DNA Nanotechnology

Bispecific antibodies (bsAbs) are emerging immune-therapeutics, and many formats exist that differ considerably in structure. However, little systematic data exist about how the spatial organization of their components influences activity, requiring innovative approaches combining empirical and quantitative frameworks. This study presents a modular DNA nanotechnology platform to generate numerous bsAbs with surrogate geometries that span the structural features of the BiTE, IgG-like, and IgG-conjugate platforms to screen for T-cell engagement. Results highlight interesting structure-activity relationships regarding bsAb potency and selectivity and raise questions regarding the molecular phenomena underlying activity. To elucidate some effects, the platform was paired with a simple mathematical model. This work is thus one of the first to systematically investigate and reveal the importance of the spatial organization of bsAb components on activity and equally provides an accessible and convenient tool for rapidly mapping out such trends for other combinations of target epitopes.

A Pediatric Case of B Cell Precursor ALL With Blinatumomab-associated Encephalopathy

Blinatumomab is a CD3/CD19-directed bispecific T-cell engager used to treat relapsed or refractory B-cell precursor acute lymphoblastic leukemia (BCP-ALL). Although blinatumomab has shown efficacy, it can cause serious adverse events, including cytokine release syndrome and neurological events. Among the neurological events, encephalopathy is rare, and knowledge is lacking. Herein, we present a pediatric case of blinatumomab-associated encephalopathy that initially presented with refractory convulsions and later developed into a cerebral infarction. The patient experienced prolonged paralysis and increased brain damage.

Bispecific FpFs: a versatile tool for preclinical antibody development

We previously described FpFs 1̲ (Fab-PEG-Fab) as binding mimetics of IgGs. FpFs are prepared with di(bis-sulfone) conjugation reagents 3̲ that undergo disulfide rebridging conjugation with the accessible disulfide of each Fab (Scheme 1). We have now prepared bispecific FpFs 2̲ (bsFpF and Fab1-PEG-Fab2) as potential bispecific antibody mimetics with the intent that bsFpFs could be used in preclinical antibody development since sourcing bispecific antibodies may be challenging during preclinical research. The di(bis-sulfone) reagent 3̲ was first used to prepare a bsFpF 2̲ by the sequential conjugation of a first Fab and then a second Fab to another target (Scheme 2). Seeking to improve bsFpF synthesis, the asymmetric conjugation reagent, bis-sulfone bis-sulfide 1̲6̲, with different thiol conjugation reactivities at each terminus (Scheme 4) was examined and the bsFpFs appeared to be formed at similar conversion to the di(bis-sulfone) reagent 3̲. To explore the advantages of using common intermediates in the preparation of bsFpF families, we investigated bsFpF synthesis with a protein conjugation-ligation approach (Scheme 5). Reagents with a bis-sulfone moiety for conjugation on one PEG terminus and a ligation moiety on the other terminus were examined. Bis-sulfone PEG trans-cyclooctene (TCO) 2̲8̲ and bis-sulfone PEG tetrazine (Tz) 3̲0̲ were used to prepare several bsFpFs targeting various therapeutic targets (TNF-α, IL6R, IL17, and VEGF) and tissue affinity targets (hyaluronic acid and collagen II). Surface plasmon resonance (SPR) binding studies indicated that there was little difference between the dissociation rate constant (k d) for the unmodified Fab, mono-conjugated PEG-Fab and the corresponding Fab in a bsFpF. The Fab association rate (k a) in the bsFpF was slower than for PEG-Fab, which may be because of mass differences that influence SPR results. These observations suggest that each Fab will bind to its target independently of the other Fab and that bsFpF binding profiles can be estimated using the corresponding PEG-Fab conjugates.

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.

Population Pharmacokinetics (PopPK) Support for Pediatric Dosing of Biological Products

This study assesses the use of population pharmacokinetics (PopPK) in supporting pediatric dosing of novel biological drug products. The labeling for biologic drug products approved by the US Food and Drug Administration (FDA) from 2002 until 2021 was reviewed to identify those with a pediatric indication. For the drugs with a pediatric indication, the dosing regimen(s) based on age groups, dosing strategy, the use of PopPK to support the dose, and the types of pediatric clinical trials were reviewed. Data were collected from FDA's review documents and product labels on the Drugs@FDA website, and as needed, more clinical trial details were collected from PubMed and clinicaltrials.gov. The role of PopPK analyses in dosing was captured when mentioned in the label or review as playing a role in selecting the approved pediatric dose and/or in verifying the adequacy of the studied dose to support labeling. Between 2002 and 2021, FDA approved 169 biological products, and 78 of 169 (46%) products have an approved indication for which the label contains dosing recommendations for pediatric use. For the 78 products approved in pediatrics, there was a total of 180 clinical trials that included pediatric patients. Phase 3 pediatric trials commonly supported pediatric approval and dosing for the reviewed products (64%, 50/78 products; 56.1%, 101/180 trials). PopPK analyses were reported to play a critical role in dose selection, prediction, and verification for 40 of the 78 products (51%), including informing pediatric dosing in the absence of pediatric data (e.g., drugs approved under animal rule), comparing exposures to the exposure range observed in adults, and informing alternative dosing strategies in certain age or body weight groups. PopPK analyses have been applied in a variety of ways to inform pediatric dosing and support extrapolation from adult data or other pediatric age groups for biologics. Understanding and learning from these past cases on the use of pharmacometrics tools to support pediatric dosing of biological products can inform future pediatric development programs.

Treatment of Relapsed Acute Lymphocytic Leukemia in Adult Patients

OPINION STATEMENT

For adult patients diagnosed with relapsed B cell-ALL (B-ALL), there have been significant improvements in available treatment options following the FDA approval of novel cellular and immunotherapy approaches - blinatumomab, chimeric antigen receptor (CAR) T therapy, and inotuzumab. For the last several years, research has focused on gaining a better understanding of the effects of specific disease and patient characteristics on long-term outcomes with each of the FDA-approved agents. In combination with the better prevention and management of unique, treatment-specific toxicities, providers can now select the best available treatment option for each individual patient diagnosed with relapsed, adult B-ALL needing therapy. This has allowed more patients to proceed to consolidative hematopoietic stem cell transplant (HSCT), and long-term data has even brought into question the need for HSCT for long-term durable remission for all patients. However, with the adoption of blinatumomab, CAR T therapy, and inotuzumab in front-line treatment regimens, it remains unclear what effects this will have on patients with relapsed B-ALL following exposure to these novel cellular and immunotherapy therapies. Unlike B-ALL, similar advances have unfortunately not yet been realized in T cell-ALL (T-ALL). Currently, new therapeutic approaches are underway to utilize similar targeting strategies that have been successful in B-ALL - monoclonal antibodies, bispecific T-cell engagers (BiTE), and CAR T therapy. Like B-ALL, the only existing approved therapy for relapsed T-ALL, nelarabine, is now used in the upfront treatment setting potentially limiting its utility in relapsed disease. Over the next several years, the hope is for patients diagnosed with T-ALL to experience the drastic improvement in outcomes as has been seen for patients diagnosed with B-ALL over the last decade.

Protein Grafting Techniques: From Peptide Epitopes to Lasso-Grafted Neobiologics

Protein engineering techniques have vastly expanded their domain of impact, notably following the success of antibodies. Likewise, smaller peptide therapeutics have carved an increasingly significant niche for themselves in the pharmaceutical landscape. The concept of grafting such peptides onto larger protein scaffolds, thus harvesting the advantages of both, has given rise to a variety of protein engineering strategies that are reviewed herein. We also describe our own "Lasso-Grafting" approach, which combines traditional grafting concepts with mRNA display to streamline the production of multiple grafted drug candidates for virtually any target.

Humanization of the antigen-recognition domain does not impinge on the antigen-binding, cytokine secretion, and antitumor reactivity of humanized nanobody-based CD19-redirected CAR-T cells

BACKGROUND

The immunogenicity of the antigen-recognition domains of chimeric antigen receptor (CAR)-T cells leads to immune responses that may compromise the antitumor effects of the adoptively transferred T cells. Herein, we attempt to humanize a CD19-specific VHH (named H85) using in silico techniques and investigate the impact of antigen-recognition domain humanization on CAR expression and density, cytokine secretion, and cytolytic reactivity of CAR-T cells based on the humanized VHH.

METHODS

H85 was humanized (named HuH85), and then HuH85 was compared with H85 in terms of conformational structure, physicochemical properties, antigenicity and immunogenicity, solubility, flexibility, stability, and CD19-binding capacity using in silico techniques. Next, H85CAR-T cells and HuH85CAR-T cells were developed and CAR expression and surface density were assessed via flow cytometry. Ultimately, the antitumor reactivity and secreted levels of IFN-γ, IL-2, and TNF-α were assessed following the co-cultivation of the CAR-T cells with Ramos, Namalwa, and K562 cells.

RESULTS

In silico findings demonstrated no negative impacts on HuH85 as a result of humanization. Ultimately, H85CAR and HuH85CAR could be surface-expressed on transduced T cells at comparable levels as assessed via mean fluorescence intensity. Moreover, H85CAR-T cells and HuH85CAR-T cells mediated comparable antitumor effects against Ramos and Namalwa cells and secreted comparable levels of IFN-γ, IL-2, and TNF-α following co-cultivation.

CONCLUSION

HuH85 can be used to develop immunotherapeutics against CD19-associated hematologic malignancies. Moreover, HuH85CAR-T cells must be further investigated in vitro and in preclinical xenograft models of CD19+ leukemias and lymphomas before advancing into clinical trials.

Optimizing the Design and Geometry of T Cell-Engaging Bispecific Antibodies Targeting CEA in Colorectal Cancer

Metastatic colorectal cancer remains a leading cause of cancer-related deaths, with a 5-year survival rate of only 15%. T cell-engaging bispecific antibodies (TCBs) represent a class of biopharmaceuticals that redirect cytotoxic T cells toward tumor cells, thereby turning immunologically "cold" tumors into "hot" ones. The carcinoembryonic antigen (CEA) is an attractive tumor-associated antigen that is overexpressed in more than 98% of patients with colorectal cancer. In this study, we report the comparison of four different TCB formats employing the antibodies F4 (targeting human CEA) and 2C11 (targeting mouse CD3ε). These formats include both antibody fragment-based and IgG-based constructs, with either one or two binding specificities of the respective antibodies. The 2 + 1 arrangement, using an anti-CEA single-chain diabody fused to an anti-CD3 single-chain variable fragment, emerged as the most potent design, showing tumor killing at subnanomolar concentrations across three different CEA+ cell lines. The in vitro activity was three times greater in C57BL/6 mouse colon adenocarcinoma cells (MC38) expressing high levels of CEA compared with those expressing low levels, highlighting the impact of CEA density in this assay. The optimal TCB candidate was tested in two different immunocompetent mouse models of colorectal cancer and showed tumor growth retardation. Ex vivo analysis of tumor infiltrates showed an increase in CD4+ and CD8+ T cells upon TCB treatment. This study suggests that bivalent tumor targeting, monovalent T-cell targeting, and a short spatial separation are promising characteristics for CEA-targeting TCBs.

Utilizing immunotherapy towards achieving a functional cure for HIV-1

PURPOSE OF REVIEW

Advancements in antiretroviral therapy (ART) have positively impacted the life expectancy and possibility of living a normal life for people with HIV-1. However, lifelong daily medication is necessary to prevent disease progression. To this end, immunotherapeutic strategies are being tested with the aim of developing a functional cure in which the immune system effectively controls HIV-1 in the absence of ART.

RECENT FINDINGS

The most promising advances in achieving sustained HIV-1 remission or cure include broadly neutralizing antibodies (bNAbs) that are administered alone or in combination with other agents. Newer and more innovative approaches redirecting T cells or natural killer cells to kill HIV-1 infected cells have also shown promising results. Finally, multiple ongoing trials focus on combining bNAbs with other immune-directed therapies to enhance both innate and adaptive immunity.

SUMMARY

While immunotherapies as an alternative to conventional ART have generally proven to be well tolerated, these therapeutic approaches have largely been unsuccessful in inducing ART-free control of HIV-1. However, promising results from recent trials involving bNAbs that have reported durable HIV-1 control among a subset of participants, provide reason for cautious optimism that we with further optimization of these treatment strategies may be able to achieve functional cure for HIV-1.

PHE1-based IgG-like antibody platform provides a novel strategy for enhanced T-cell immunotherapy

Introduction

Bispecific antibodies (BsAbs) can simultaneously target two epitopes of different antigenic targets, bringing possibilities for diversity in antibody drug design and are promising tools for the treatment of cancers and other diseases. T-cell engaging bsAb is an important application of the bispecific antibody, which could promote T cell-mediated tumor cell killing by targeting tumor-associated antigen (TAA) and CD3 at the same time.

Methods

This study comprised antibodies purification, Elisa assay for antigen binding, cytotoxicity assays, T cell activation by flow cytometry in vitro and xenogenic tumor model in vivo.

Results

We present a novel bsAb platform named PHE-Ig technique to promote cognate heavy chain (HC)-light chain (LC) pairing by replacing the CH1/CL regions of different monoclonal antibodies (mAbs) with the natural A and B chains of PHE1 fragment of Integrin β2 based on the knob-in-hole (KIH) technology. We had also verified that PHE-Ig technology can be effectively used as a platform to synthesize different desired bsAbs for T-cell immunotherapy. Especially, BCMA×CD3 PHE-Ig bsAbs exhibited robust anti-multiple myeloma (MM) activity in vitro and in vivo.

Discussion

Moreover, PHE1 domain was further shortened with D14G and R41S mutations, named PHE-S, and the PHE-S-based BCMA×CD3 bsAbs also showed anti BCMA+ tumor effect in vitro and in vivo, bringing more possibilities for the development and optimization of different bsAbs. To sum up, PHE1-based IgG-like antibody platform for bsAb construction provides a novel strategy for enhanced T-cell immunotherapy.

Nonclinical Investigation of Cytokine Mitigation Strategies for T-cell-Engaging Bispecifics in the Cynomolgus Macaque

SUMMARY

T-cell-directed cancer therapies such as T-cell-engaging bispecifics (TCBs) are commonly associated with cytokine release syndrome and associated clinical signs that can limit their tolerability and therapeutic benefit. Strategies for reducing cytokine release are therefore needed. Here, we report on studies performed in cynomolgus monkeys to test different approaches for mitigating cytokine release with TCBs. A "priming dose" as well as subcutaneous dosing reduced cytokine release compared with intravenous dosing but did not affect the intended T-cell response to the bispecific. As another strategy, cytokines or cytokine responses were blocked with an anti-IL-6 antibody, dexamethasone, or a JAK1/TYK2-selective inhibitor, and the effects on toxicity as well as T-cell responses to a TCB were evaluated. The JAK1/TYK2 inhibitor and dexamethasone prevented CRS-associated clinical signs on the day of TCB administration, but the anti-IL-6 had little effect. All interventions allowed for functional T-cell responses and expected damage to target-bearing tissues, but the JAK1/TYK2 inhibitor prevented the upregulation of activation markers on T cells, suggesting the potential for suppression of T-cell responses. Our results suggest that short-term prophylactic dexamethasone treatment may be an effective option for blocking cytokine responses without affecting desired T-cell responses to TCBs.

Bispecific T-cell engagers in childhood B-acute lymphoblastic leukemia

Immunotherapy has revolutionized treatment for a wide variety of cancers yet its use has been relatively limited in childhood malignancies. With the introduction of bispecific T-cell engagers (BiTE®) and chimeric antigen T-cell receptor technologies, previously refractory patients have attained remission, including molecularly negative states of disease, thus providing the possibility of long-term cure. Blinatumomab is a widely available CD3-CD19 BiTE that has dramatically changed the landscape of therapy for some children with precursor-B acute lymphoblastic leukemias (B-ALL) and lymphoblastic lymphomas. Challenges remain with using BiTE in a broader population although the appeal of now-confirmed reduced toxicity and deeper molecular remissions suggests that this approach will be an essential part of future treatment of childhood B-ALL. Herein, we review some of the pertinent literature covering clinical trials with blinatumomab and address future approaches and combination trials including BiTE.

Impact of Treatment Modality and Route of Administration on Cytokine Release Syndrome in Relapsed or Refractory Multiple Myeloma: A Meta-Analysis

B-cell maturation antigen (BCMA)-targeting immunotherapies (e.g., chimeric antigen receptor T cells (CAR-T) and bispecific antibodies (BsAbs)) have achieved remarkable clinical responses in patients with relapsed and/or refractory multiple myeloma (RRMM). Their use is accompanied by exaggerated immune responses related to T-cell activation and cytokine elevations leading to cytokine release syndrome (CRS) in some patients, which can be potentially life-threatening. However, systematic evaluation of the risk of CRS with BCMA-targeting BsAb and CAR-T therapies, and comparisons across different routes of BsAb administration (intravenous (i.v.) vs. subcutaneous (s.c.)) have not previously been conducted. This study utilized a meta-analysis approach to compare the CRS profile in BCMA-targeting CAR-T vs. BsAb immunotherapies administered either i.v. or s.c. in patients with RRMM. A total of 36 studies including 1,560 patients with RRMM treated with BCMA-targeting CAR-T and BsAb therapies were included in the analysis. The current analysis suggests that compared with BsAbs, CAR-T therapies were associated with higher CRS incidences (88% vs. 59%), higher rates of grade ≥ 3 CRS (7% vs. 2%), longer CRS duration (5 vs. 2 days), and more prevalent tocilizumab use (44% vs. 25%). The proportion of CRS grade ≥ 3 may also be lower (0% vs. 4%) for BsAb therapies administered via the s.c. (3 studies, n = 311) vs. i.v. (5 studies, n = 338) route. This meta-analysis suggests that different types of BCMA-targeting immunotherapies and administration routes could result in a range of CRS incidence and severity that should be considered while evaluating the benefit-risk profiles of these therapies.

Understanding the immunosuppressive microenvironment of glioma: mechanistic insights and clinical perspectives

Glioblastoma (GBM), the predominant and primary malignant intracranial tumor, poses a formidable challenge due to its immunosuppressive microenvironment, thereby confounding conventional therapeutic interventions. Despite the established treatment regimen comprising surgical intervention, radiotherapy, temozolomide administration, and the exploration of emerging modalities such as immunotherapy and integration of medicine and engineering technology therapy, the efficacy of these approaches remains constrained, resulting in suboptimal prognostic outcomes. In recent years, intensive scrutiny of the inhibitory and immunosuppressive milieu within GBM has underscored the significance of cellular constituents of the GBM microenvironment and their interactions with malignant cells and neurons. Novel immune and targeted therapy strategies have emerged, offering promising avenues for advancing GBM treatment. One pivotal mechanism orchestrating immunosuppression in GBM involves the aggregation of myeloid-derived suppressor cells (MDSCs), glioma-associated macrophage/microglia (GAM), and regulatory T cells (Tregs). Among these, MDSCs, though constituting a minority (4-8%) of CD45+ cells in GBM, play a central component in fostering immune evasion and propelling tumor progression, angiogenesis, invasion, and metastasis. MDSCs deploy intricate immunosuppressive mechanisms that adapt to the dynamic tumor microenvironment (TME). Understanding the interplay between GBM and MDSCs provides a compelling basis for therapeutic interventions. This review seeks to elucidate the immune regulatory mechanisms inherent in the GBM microenvironment, explore existing therapeutic targets, and consolidate recent insights into MDSC induction and their contribution to GBM immunosuppression. Additionally, the review comprehensively surveys ongoing clinical trials and potential treatment strategies, envisioning a future where targeting MDSCs could reshape the immune landscape of GBM. Through the synergistic integration of immunotherapy with other therapeutic modalities, this approach can establish a multidisciplinary, multi-target paradigm, ultimately improving the prognosis and quality of life in patients with GBM.

Immune therapies of B-cell acute lymphoblastic leukaemia in children and adults

B-cell acute lymphoblastic leukaemia (B-cell ALL) is a common haematologic cancer in children and adults. About 10 percent of children and 50 percent of adults fail to achieve a histological complete remission or subsequently relapse despite current anti-leukaemia drug therapies and/or haematopoietic cell transplants. Several new immune therapies including monoclonal antibodies and chimeric antigen receptor (CAR)-T-cells are proved safe and effective in this setting. We review data on US Food and Drug Administration (FDA)-approved immune therapies for B-cell ALL in children and adults including blinatumomab, inotuzumab ozogamicin, tisagenlecleucel, and brexucabtagene autoleucel. We also summarize pharmaco-dynamics, pharmaco-kinetics, and pharmaco-economics of these interventions.

The enhanced antitumor activity of bispecific antibody targeting PD-1/PD-L1 signaling

The programmed cell death 1 (PD-1) signaling pathway, a key player in immune checkpoint regulation, has become a focal point in cancer immunotherapy. In the context of cancer, upregulated PD-L1 on tumor cells can result in T cell exhaustion and immune evasion, fostering tumor progression. The advent of PD-1/PD-L1 inhibitor has demonstrated clinical success by unleashing T cells from exhaustion. Nevertheless, challenges such as resistance and adverse effects have spurred the exploration of innovative strategies, with bispecific antibodies (BsAbs) emerging as a promising frontier. BsAbs offer a multifaceted approach to cancer immunotherapy by simultaneously targeting PD-L1 and other immune regulatory molecules. We focus on recent advancements in PD-1/PD-L1 therapy with a particular emphasis on the development and potential of BsAbs, especially in the context of solid tumors. Various BsAb products targeting PD-1 signaling are discussed, highlighting their unique mechanisms of action and therapeutic potential. Noteworthy examples include anti-TGFβ × PD-L1, anti-CD47 × PD-L1, anti-VEGF × PD-L1, anti-4-1BB × PD-L1, anti-LAG-3 × PD-L1, and anti-PD-1 × CTLA-4 BsAbs. Besides, we summarize ongoing clinical studies evaluating the efficacy and safety of these innovative BsAb agents. By unraveling the intricacies of the tumor microenvironment and harnessing the synergistic effects of anti-PD-1/PD-L1 BsAbs, there exists the potential to elevate the precision and efficacy of cancer immunotherapy, ultimately enabling the development of personalized treatment strategies tailored to individual patient profiles.

Bispecific antibodies promote natural killer cell-mediated elimination of HIV-1 reservoir cells

The persistence of CD4+ T cells carrying latent human immunodeficiency virus-1 (HIV-1) proviruses is the main barrier to a cure. New therapeutics to enhance HIV-1-specific immune responses and clear infected cells will probably be necessary to achieve reduction of the latent reservoir. In the present study, we report two single-chain diabodies (scDbs) that target the HIV-1 envelope protein (Env) and the human type III Fcγ receptor (CD16). We show that the scDbs promoted robust and HIV-1-specific natural killer (NK) cell activation and NK cell-mediated lysis of infected cells. Cocultures of CD4+ T cells from people with HIV-1 on antiretroviral therapy (ART) with autologous NK cells and the scDbs resulted in marked elimination of reservoir cells that was dependent on latency reversal. Treatment of human interleukin-15 transgenic NSG mice with one of the scDbs after ART initiation enhanced NK cell activity and reduced reservoir size. Thus, HIV-1-specific scDbs merit further evaluation as potential therapeutics for clearance of the latent reservoir.

Subcutaneous Administration of Monoclonal Antibodies: Pharmacology, Delivery, Immunogenicity, and Learnings From Applications to Clinical Development

Subcutaneous (s.c.) administration of monoclonal antibodies (mAbs) can reduce treatment burden for patients and healthcare systems compared with intravenous (i.v.) infusion through shorter administration times, made possible by convenient, patient-centric devices. A deeper understanding of clinical pharmacology principles related to efficacy and safety of s.c.-administered mAbs over the past decade has streamlined s.c. product development. This review presents learnings from key constituents of the s.c. mAb development pathway, including pharmacology, administration variables, immunogenicity, and delivery devices. Restricted mAb transportation through the hypodermis explains their incomplete absorption at a relatively slow rate (pharmacokinetic (PK)) and may impact mAb-cellular interactions and/or onset and magnitude of physiological responses (pharmacodynamic). Injection volumes, formulation, rate and site of injection, and needle attributes may affect PKs and the occurrence/severity of adverse events like injection-site reactions or pain, with important consequences for treatment adherence. A review of immunogenicity data for numerous compounds reveals that incidence of anti-drug antibodies (ADAs) is generally comparable across i.v. and s.c. routes, and complementary factors including response magnitude (ADA titer), persistence over time, and neutralizing antibody presence are needed to assess clinical impact. Finally, four case studies showcase how s.c. biologics have been clinically developed: (i) by implementation of i.v./s.c. bridging strategies to streamline PD-1/PD-L1 inhibitor development, (ii) through co-development with i.v. presentations for anti-severe acute respiratory syndrome-coronavirus 2 antibodies to support rapid deployment of both formulations, (iii) as the lead route for bispecific T cell engagers (BTCEs) to mitigate BTCE-mediated cytokine release syndrome, and (iv) for pediatric patients in the case of dupilumab.

Arming oncolytic viruses with bispecific T cell engagers: The evolution and current status

Oncolytic viruses (OVs) are emerging as therapeutically relevant anticancer agents as contemporary immunotherapy gains traction. Furthermore, OVs are an ideal platform for genetic modification to express therapeutic transgenes. Bispecific T cell engagers (BiTEs) can redirect T cells to tumor cells, resulting in targeted cytotoxicity. BiTEs have demonstrated success in hematological cancers but are rarely used in solid tumors. The drawbacks of BiTEs, including inadequate delivery and on-target-off-tumor activity have limited their efficacy. Combining OVs with BiTEs is a prospective area to investigate. This combined strategy can benefit from the best qualities of both therapies while overcoming the limitations.

Blinatumomab in Practice

PURPOSE OF REVIEW

Acute lymphoblastic leukemia (ALL) is a rare hematologic neoplasm in adults, with most cases defined by pathology related to abnormal B cell proliferation known as B-cell ALL. The course is challenging, with less-than-optimal survival outcomes, even with aggressive multiagent chemotherapy and consideration for stem cell transplantation. Novel therapies focused on targetable pathways are being investigated to improve outcomes while simultaneously decreasing toxicity. In our review, we aim to evaluate the utilization of blinatumomab in B-cell ALL and provide insight on how this guides our management.

RECENT FINDINGS

Blinatumomab is a bispecific T-cell engager (BiTE) immunotherapy that neutralizes malignant cells by instigating CD3-positive T cells to target CD19-positive B cells. However, this therapy targets both malignant and non-malignant lymphocytes with potentially severe side effects such as cytokine release syndrome or neurotoxicity. Evidence evaluating utilization in the relapsed or refractory setting has been most supported; however, newer trials have also indicated improved survival in the frontline treatment of B-cell ALL. As this therapy is relatively new, the treatment team may include members who are less experienced with the typical treatment course and drug mechanics. This review synthesized available data investigating the effectiveness of blinatumomab effectiveness and its adverse events in addition to providing guidance on safe administration methods utilizing a multidisciplinary healthcare team. When care is coordinated in these settings, serious side effects can be recognized early, allowing for necessary intervention leading to improved quality of life and overall survival. Future research will continue to evaluate blinatumomab in different lines of therapy and expand its way into community settings.

Bispecific Antibodies Produced via Chemical Site-Specific Conjugation Technology: AJICAP Second-Generation

Bispecific antibodies (BisAbs) are biotherapeutics that amalgamate the specificities of two distinct antibodies into one molecule, however, their engineering requires genetic modification and remains time-consuming. Therefore, we used AJICAP second-generation technology, which drives the production of site-specific conjugation without genetic modification requirements, to generate BisAbs. Using haloketone chemistry as an alternative to maleimide chemistry, we successfully produced site-specific antibody conjugates. Pharmacokinetic studies revealed that the haloketone-based antibody conjugate was stable in the rat plasma. The resultant BisAbs were rigorously evaluated, and surface plasmon resonance measurements and flow cytometry analyses confirmed that the antigen binding remained intact. Additionally, the affinity for the neonatal Fc receptor (FcRn) was retained after conjugation. Further cytotoxicity evaluation emphasized the pronounced activity of the generated BisAbs. This novel approach introduces a fully chemical, site-specific strategy capable of producing BisAbs, heralding a new era in the field of biotherapeutics.

Designing Multivalent and Multispecific Biologics

In the era of precision medicine, multivalent and multispecific therapeutics present a promising approach for targeted disease intervention. These therapeutics are designed to interact with multiple targets simultaneously, promising enhanced efficacy, reduced side effects, and resilience against drug resistance. We dissect the principles guiding the design of multivalent biologics, highlighting challenges and strategies that must be considered to maximize therapeutic effect. Engineerable elements in multivalent and multispecific biologic design-domain affinities, valency, and spatial presentation-must be considered in the context of the molecular targets as well as the balance of important properties such as target avidity and specificity. We illuminate recent applications of these principles in designing protein and cell therapies and identify exciting future directions in this field, underscored by advances in biomolecular and cellular engineering and computational approaches. Expected final online publication date for the Annual Review of Chemical and Biomolecular Engineering , Volume 15 is June 2024. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Revolutionizing cancer immunotherapy: unleashing the potential of bispecific antibodies for targeted treatment

Recent progressions in immunotherapy have transformed cancer treatment, providing a promising strategy that activates the immune system of the patient to find and eliminate cancerous cells. Bispecific antibodies, which engage two separate antigens or one antigen with two distinct epitopes, are of tremendous concern in immunotherapy. The bi-targeting idea enabled by bispecific antibodies (BsAbs) is especially attractive from a medical standpoint since most diseases are complex, involving several receptors, ligands, and signaling pathways. Several research look into the processes in which BsAbs identify different cancer targets such angiogenesis, reproduction, metastasis, and immune regulation. By rerouting cells or altering other pathways, the bispecific proteins perform effector activities in addition to those of natural antibodies. This opens up a wide range of clinical applications and helps patients with resistant tumors respond better to medication. Yet, further study is necessary to identify the best conditions where to use these medications for treating tumor, their appropriate combination partners, and methods to reduce toxicity. In this review, we provide insights into the BsAb format classification based on their composition and symmetry, as well as the delivery mode, focus on the action mechanism of the molecule, and discuss the challenges and future perspectives in BsAb development.

Methods for Engineering Binders to Multi-Pass Membrane Proteins

Numerous potential drug targets, including G-protein-coupled receptors and ion channel proteins, reside on the cell surface as multi-pass membrane proteins. Unfortunately, despite advances in engineering technologies, engineering biologics against multi-pass membrane proteins remains a formidable task. In this review, we focus on the different methods used to prepare/present multi-pass transmembrane proteins for engineering target-specific biologics such as antibodies, nanobodies and synthetic scaffold proteins. The engineered biologics exhibit high specificity and affinity, and have broad applications as therapeutics, probes for cell staining and chaperones for promoting protein crystallization. We primarily cover publications on this topic from the past 10 years, with a focus on the different formats of multi-pass transmembrane proteins. Finally, the remaining challenges facing this field and new technologies developed to overcome a number of obstacles are discussed.

Editorial on "Cell Therapy, Bispecific Antibodies and Other Immunotherapies against Cancer"

This Special Issue in Cancers, "Cell Therapy, Bispecific Antibodies and other Immunotherapies Against Cancer", includes interesting reports and reviews on cell therapies and bispecific antibodies [...].

A Novel bispecific T-cell engager (BiTE) targeting CD22 and CD3 has both in vitro and in vivo activity and synergizes with blinatumomab in an acute lymphoblastic leukemia (ALL) tumor model

Immunotherapy has revolutionized cancer therapy. Two recently FDA-approved immunotherapies for B-cell malignancies target CD19, in the form of a Bispecific T-Cell Engager (BiTE) antibody construct or chimeric antigen receptor T (CAR-T) cells. Blinatumomab, an FDA-approved BiTE, binds to CD19 on B cells and to CD3 on T cells, mediating effector-target cell contact and T-cell activation that results in effective elimination of target B cells. Although CD19 is expressed by essentially all B-cell malignancies at clinical presentation, relapses with loss or reduction in CD19 surface expression are increasingly recognized as a cause of treatment failure. Therefore, there is a clear need to develop therapeutics for alternate targets. We have developed a novel BiTE consisting of humanized anti-CD22 and anti-CD3 single chain variable fragments. Target binding of the anti-CD22 and anti-CD3 moieties was confirmed by flow cytometry. CD22-BiTE promoted in vitro cell-mediated cytotoxicity in a dose and effector: target (E:T)-dependent fashion. Additionally, in an established acute lymphoblastic leukemia (ALL) xenograft mouse model, CD22-BiTE demonstrated tumor growth inhibition, comparable to blinatumomab. Further, the combination of blinatumomab and CD22-BiTE yielded increased efficacy in vivo when compared to the single agents. In conclusion, we report here the development of a new BiTE with cytotoxic activity against CD22+ cells which could represent an alternate or complementary therapeutic option for B-cell malignancies.

Cross-linking disulfide bonds govern solution structures of diabodies

In the last years, antibodies have emerged as a promising new class of therapeutics, due to their combination of high specificity with long serum half-life and low risk of side-effects. Diabodies are a popular novel antibody format, consisting of two Fv domains connected with short linkers. Like IgG antibodies, they simultaneously bind two target proteins. However, they offer altered properties, given their smaller size and higher rigidity. In this study, we conducted the-to our knowledge-first molecular dynamics (MD) simulations of diabodies and find a surprisingly high conformational flexibility in the relative orientation of the two Fv domains. We observe rigidifying effects through the introduction of disulfide bonds in the Fv -Fv interface and characterize the effect of different disulfide bond locations on the conformation. Additionally, we compare VH -VL orientations and paratope dynamics between diabodies and an antigen binding fragment (Fab) of the same sequence. We find mostly consistent structures and dynamics, indicating similar antigen binding properties. The most significant differences can be found within the CDR-H2 loop dynamics. Of all CDR loops, the CDR-H2 is located closest to the artificial Fv -Fv interface. All examined diabodies show similar VH -VL orientations, Fv -Fv packing and CDR loop conformations. However, the variant with a P14C-K64C disulfide bond differs most from the Fab in our measures, including the CDR-H3 loop conformational ensemble. This suggests altered antigen binding properties and underlines the need for careful validation of the disulfide bond locations in diabodies.

Harnessing the immunomodulatory effects of exercise to enhance the efficacy of monoclonal antibody therapies against B-cell haematological cancers: a narrative review

Therapeutic monoclonal antibodies (mAbs) are standard care for many B-cell haematological cancers. The modes of action for these mAbs include: induction of cancer cell lysis by activating Fcγ-receptors on innate immune cells; opsonising target cells for antibody-dependent cellular cytotoxicity or phagocytosis, and/or triggering the classical complement pathway; the simultaneous binding of cancer cells with T-cells to create an immune synapse and activate perforin-mediated T-cell cytotoxicity against cancer cells; blockade of immune checkpoints to facilitate T-cell cytotoxicity against immunogenic cancer cell clones; and direct delivery of cytotoxic agents via internalisation of mAbs by target cells. While treatment regimens comprising mAb therapy can lead to durable anti-cancer responses, disease relapse is common due to failure of mAb therapy to eradicate minimal residual disease. Factors that limit mAb efficacy include: suboptimal effector cell frequencies, overt immune exhaustion and/or immune anergy, and survival of diffusely spread tumour cells in different stromal niches. In this review, we discuss how immunomodulatory changes arising from exposure to structured bouts of acute exercise might improve mAb treatment efficacy by augmenting (i) antibody-dependent cellular cytotoxicity, (ii) antibody-dependent cellular phagocytosis, (iii) complement-dependent cytotoxicity, (iv) T-cell cytotoxicity, and (v) direct delivery of cytotoxic agents.

Immunotherapy in hematologic malignancies: achievements, challenges and future prospects

The immune-cell origin of hematologic malignancies provides a unique avenue for the understanding of both the mechanisms of immune responsiveness and immune escape, which has accelerated the progress of immunotherapy. Several categories of immunotherapies have been developed and are being further evaluated in clinical trials for the treatment of blood cancers, including stem cell transplantation, immune checkpoint inhibitors, antigen-targeted antibodies, antibody-drug conjugates, tumor vaccines, and adoptive cell therapies. These immunotherapies have shown the potential to induce long-term remission in refractory or relapsed patients and have led to a paradigm shift in cancer treatment with great clinical success. Different immunotherapeutic approaches have their advantages but also shortcomings that need to be addressed. To provide clinicians with timely information on these revolutionary therapeutic approaches, the comprehensive review provides historical perspectives on the applications and clinical considerations of the immunotherapy. Here, we first outline the recent advances that have been made in the understanding of the various categories of immunotherapies in the treatment of hematologic malignancies. We further discuss the specific mechanisms of action, summarize the clinical trials and outcomes of immunotherapies in hematologic malignancies, as well as the adverse effects and toxicity management and then provide novel insights into challenges and future directions.

Short-course blinatumomab for refractory/relapse precursor B acute lymphoblastic leukemia in children

Objective

To evaluate the clinical efficacy and safety of a short course of blinatumomab in children with refractory or relapsed precursor B-cell acute lymphoblastic leukemia (R/R-BCP-ALL).

Methods

The clinical data of 33 R/R BCP-ALL children aged 0-18 years who underwent a short course of blinatumomab (14 days) between August 2021 and November 2022 were retrospectively collected and analyzed.

Results

Among 33 patients with BCP-ALL, 26 achieved complete remission (CR), with a total remission rate of 78.8% (26/33). The duration of remission was approximately 14 days. Of the 7 children without CR, 5 were still in remission at 28 days. In 11 patients with refractory disease and 22 with recurrence, the remission rates were 90.9% (10/11) and 72.7% (16/22), respectively. The overall survival (OS) rates of the 26 patients with CR and seven patients without CR were 96.1% and 57.1% (p = 0.002), respectively, and the disease-free survival (DFS) rates were 96.1% and 42.9% (p < 0.001), respectively. Among the 26 patients with CR, 15 underwent bridging hematopoietic stem cell transplantation (HSCT) and 11 did not receive HSCT; with OS rates of 93.3% and 100% (p = 0.40) and DFS rates of 93.3% and 100% (p = 0.400), respectively. The OS for all patients was 87.9% (29/33) and the DFS was 84.8% (28/33). There were 18 cases (54.5%) of cytokine release syndrome (CRS), 2 cases (6.1%) of severe CRS (all grade 3), 1 case (3.0%) of immune effector cell-associated neurotoxicity syndrome (ICANS), 0 cases (0%) of ICANS ≥ grade 3, and no deaths caused by treatment.

Conclusions

Short-term follow-up revealed a high R/R BCP-ALL remission rate in children treated with a short course of blinatumomab. The toxicity was low and controllable. No significant short-term survival benefits were observed after bridging HSCT with blinatumomab. In developing countries, a short course of blinatumomab can achieve satisfactory outcomes, while reducing household costs and saving medical resources.

Population dynamics of immunological synapse formation induced by bispecific T cell engagers predict clinical pharmacodynamics and treatment resistance

Effector T cells need to form immunological synapses (IS) with recognized target cells to elicit cytolytic effects. Facilitating IS formation is the principal pharmacological action of most T cell-based cancer immunotherapies. However, the dynamics of IS formation at the cell population level, the primary driver of the pharmacodynamics of many cancer immunotherapies, remains poorly defined. Using classic immunotherapy CD3/CD19 bispecific T cell engager (BiTE) as our model system, we integrate experimental and theoretical approaches to investigate the population dynamics of IS formation and their relevance to clinical pharmacodynamics and treatment resistance. Our models produce experimentally consistent predictions when defining IS formation as a series of spatiotemporally coordinated events driven by molecular and cellular interactions. The models predict tumor-killing pharmacodynamics in patients and reveal trajectories of tumor evolution across anatomical sites under BiTE immunotherapy. Our models highlight the bone marrow as a potential sanctuary site permitting tumor evolution and antigen escape. The models also suggest that optimal dosing regimens are a function of tumor growth, CD19 expression, and patient T cell abundance, which confer adequate tumor control with reduced disease evolution. This work has implications for developing more effective T cell-based cancer immunotherapies.

A Shiga Toxin B-Subunit-Based Lectibody Boosts T Cell Cytotoxicity towards Gb3-Positive Cancer Cells

Aberrant glycosylation plays a crucial role in tumour progression and invasiveness. Tumour-associated carbohydrate antigens (TACAs) represent a valuable set of targets for immunotherapeutic approaches. The poor immunogenicity of glycan structures, however, requires a more effective and well-directed way of targeting TACAs on the surface of cancer cells than antibodies. The glycosphingolipid globotriaosylceramide (Gb3) is a well-established TACA present in a multitude of cancer types. Its overexpression has been linked to metastasis, invasiveness, and multidrug resistance. In the present study, we propose to use a dimeric fragment of the Shiga toxin B-subunit (StxB) to selectively target Gb3-positive cancer cells in a StxB-scFv UCHT1 lectibody. The lectibody, comprised of a lectin and the UCHT1 antibody fragment, was produced in E. coli and purified via Ni-NTA affinity chromatography. Specificity of the lectibody towards Gb3-positive cancer cell lines and specificity towards the CD3 receptor on T cells, was assessed using flow cytometry. We evaluated the efficacy of the lectibody in redirecting T cell cytotoxicity towards Gb3-overexpressing cancer cells in luciferase-based cytotoxicity in vitro assays. The StxB-scFv UCHT1 lectibody has proven specific for Gb3 and could induce the killing of up to 80% of Gb3-overexpressing cancer cells in haemorrhagic and solid tumours. The lectibody developed in this study, therefore, highlights the potential that lectibodies and lectins in general have for usage in immunotherapeutic approaches to boost the efficacy of established cancer treatments.

Engineering strategies of Anti-HIV antibody therapeutics in clinical development

PURPOSE OF REVIEW

Anti-human immunodeficiency virus (HIV) antibody-based therapeutics offer an alternative treatment option to current antiretroviral drugs. This review aims to provide an overview of the Fc- and Fab-engineering strategies that have been developed to optimize broadly neutralizing antibodies and discuss recent findings from preclinical and clinical studies.

RECENT FINDINGS

Multispecific antibodies, including bispecific and trispecific antibodies, DART molecules, and BiTEs, as well as Fc-optimized antibodies, have emerged as promising therapeutic candidates for the treatment of HIV. These engineered antibodies engage multiple epitopes on the HIV envelope protein and human receptors, resulting in increased potency and breadth of activity. Additionally, Fc-enhanced antibodies have demonstrated extended half-life and improved effector function.

SUMMARY

The development of Fc and Fab-engineered antibodies for the treatment of HIV continues to show promising progress. These novel therapies have the potential to overcome the limitations of current antiretroviral pharmacologic agents by more effectively suppressing viral load and targeting latent reservoirs in individuals living with HIV. Further studies are needed to fully understand the safety and efficacy of these therapies, but the growing body of evidence supports their potential as a new class of therapeutics for the treatment of HIV.

Neurologic Complications of Cancer Immunotherapy

Immunotherapy has revolutionized cancer treatment over the past decade. As it is increasingly introduced into routine clinical practice, immune-related complications have become more frequent. Accurate diagnosis and treatment are essential, with the goal of reduced patient morbidity. This review aims to discuss the various clinical manifestations, diagnosis, treatments, and prognosis of neurologic complications associated with the use of immune checkpoint inhibitors, adoptive T-cell therapies, and T-cell redirecting therapies. We also outline a suggested clinical approach related to the clinical use of these agents.

Activation of T Lymphocytes with Anti-PDL1-BiTE in the Presence of Adipose-Derived Mesenchymal Stem Cells (ASCs)

Background

Due to their ability to recruit immune cells to kill tumor cells directly, bispecific T cell engager antibodies (BiTE) hold great potential in T cell redirecting therapies. BiTE is able to activate T cells through CD3 and target them to tumor-expressed antigens. However, there are many components in the tumor microenvironment (TME) such as mesenchymal stem cells (MSCs) that may interfere with BiTE function. Herein, we designed an anti-PDL1-BiTE that targets programmed death ligand 1 (PDL1) and CD3 and investigated its effect on PDL1pos cancer cells in the presence or absence of adipose-derived MSCs (ASCs).

Method

Our anti-PDL1-BiTE comprises of VL and VH chains of anti-CD3 monoclonal antibody (mAb) linked to the VL and VH chains of anti-PDL1 mAb, which simultaneously bind to the CD3ε subunit on T cells and PDL1 on tumor cells. Flow cytometry was employed to assess the strength of binding of anti-PDL1-BiTE to tumor cells and T cells. Cytotoxicity, proliferation, and activation of peripheral blood lymphocyte (PBLs) were evaluated by CFSE assay and flow cytometry after using anti-PDL1-BiTE in the presence or absence of ASCs and their conditioned media (C.M.).

Results

Anti-PDL1-BiTE had the ability to induce selective lysis of PDL1pos U251-MG cancer cells while PDL1neg cells were not affected. Also, anti-PDL1-BiTE significantly stimulated peripheral blood lymphocyte (PBL) proliferation and CD69 expression. ASCs/C.M. did not show a significant effect on the biological activity of anti-PDL1-BiTE.

Conclusion

Overall, anti-PDL1-BiTE selectively depletes PDL1pos cells and represents a new immunotherapeutic approach. It would increase the accumulation of T cells and can improve the prognosis of PDL1pos cancers in spite of the immunomodulatory effects of ASCs and C.M.

A non-genetic engineering platform for rapidly generating and expanding cancer-specific armed T cells

BACKGROUND

Cancer-specific adoptive T cell therapy has achieved successful milestones in multiple clinical treatments. However, the commercial production of cancer-specific T cells is often hampered by laborious cell culture procedures, the concern of retrovirus-based gene transfection, or insufficient T cell purity.

METHODS

In this study, we developed a non-genetic engineering technology for rapidly manufacturing a large amount of cancer-specific T cells by utilizing a unique anti-cancer/anti-CD3 bispecific antibody (BsAb) to directly culture human peripheral blood mononuclear cells (PBMCs). The anti-CD3 moiety of the BsAb bound to the T cell surface and stimulated the differentiation and proliferation of T cells in PBMCs. The anti-cancer moiety of the BsAb provided these BsAb-armed T cells with the cancer-targeting ability, which transformed the naïve T cells into cancer-specific BsAb-armed T cells.

RESULTS

With this technology, a large amount of cancer-specific BsAb-armed T cells can be rapidly generated with a purity of over 90% in 7 days. These BsAb-armed T cells efficiently accumulated at the tumor site both in vitro and in vivo. Cytotoxins (perforin and granzyme) and cytokines (TNF-α and IFN-γ) were dramatically released from the BsAb-armed T cells after engaging cancer cells, resulting in a remarkable anti-cancer efficacy. Notably, the BsAb-armed T cells did not cause obvious cytokine release syndrome or tissue toxicity in SCID mice bearing human tumors.

CONCLUSIONS

Collectively, the BsAb-armed T cell technology represents a simple, time-saving, and highly safe method to generate highly pure cancer-specific effector T cells, thereby providing an affordable T cell immunotherapy to patients.

Inducer-free recombinant protein production in Trichoderma reesei: secretory production of endogenous enzymes and heterologous nanobodies using glucose as the sole carbon source

BACKGROUND

The filamentous fungus Trichoderma reesei has been used as a host organism for the production of lignocellulosic biomass-degrading enzymes. Although this microorganism has high potential for protein production, it has not yet been widely used for heterologous recombinant protein production. Transcriptional induction of the cellulase genes is essential for high-level protein production in T. reesei; however, glucose represses this transcriptional induction. Therefore, cellulose is commonly used as a carbon source for providing its degraded sugars such as cellobiose, which act as inducers to activate the strong promoters of the major cellulase (cellobiohydrolase 1 and 2 (cbh1 and cbh2) genes. However, replacement of cbh1 and/or cbh2 with a gene encoding the protein of interest (POI) for high productivity and occupancy of recombinant proteins remarkably impairs the ability to release soluble inducers from cellulose, consequently reducing the production of POI. To overcome this challenge, we first used an inducer-free biomass-degrading enzyme expression system, previously developed to produce cellulases and hemicellulases using glucose as the sole carbon source, for recombinant protein production using T. reesei.

RESULTS

We chose endogenous secretory enzymes and heterologous camelid small antibodies (nanobody) as model proteins. By using the inducer-free strain as a parent, replacement of cbh1 with genes encoding two intrinsic enzymes (aspartic protease and glucoamylase) and three different nanobodies (1ZVH, caplacizumab, and ozoralizumab) resulted in their high secretory productions using glucose medium without inducers such as cellulose. Based on signal sequences (carrier polypeptides) and protease inhibitors, additional replacement of cbh2 with the nanobody gene increased the percentage of POI to about 20% of total secreted proteins in T. reesei. This allowed the production of caplacizumab, a bivalent nanobody, to be increased to 9.49-fold (508 mg/L) compared to the initial inducer-free strain.

CONCLUSIONS

In general, whereas the replacement of major cellulase genes leads to extreme decrease in the degradation capacity of cellulose, our inducer-free system enabled it and achieved high secretory production of POI with increased occupancy in glucose medium. This system would be a novel platform for heterologous recombinant protein production in T. reesei.

A novel prognostic nomogram for adult acute lymphoblastic leukemia: a comprehensive analysis of 321 patients

The cure rate of acute lymphoblastic leukemia (ALL) in adolescents and adults remains poor. This study aimed to establish a prognostic model for ≥14-year-old patients with ALL to guide treatment decisions. We retrospectively analyzed the data of 321 ALL patients between January 2017 and June 2020. Patients were randomly (2:1 ratio) divided into either the training or validation set. A nomogram was used to construct a prognostic model. Multivariate Cox analysis of the training set showed that age > 50 years, white blood cell count > 28.52×10⁹/L, and MLL rearrangement were independent risk factors for overall survival (OS), while platelet count >37×10⁹/L was an independent protective factor. The nomogram was established according to these independent prognostic factors in the training set, where patients were grouped into two categories: low-risk (≤13.15) and high-risk (>13.15). The survival analysis, for either total patients or sub-group patients, showed that both OS and progression-free survival (PFS) of low-risk patients was significantly better than that of high-risk patients. Moreover, treatment analysis showed that both OS and progression-free survival (PFS) of ALL with stem cell transplantation (SCT) were significantly better than that of ALL without SCT. Further stratified analysis showed that in low-risk patients, the OS and PFS of patients with SCT were significantly better than those of patients without SCT. In contrast, in high-risk patients, compared with non-SCT patients, receiving SCT can only significantly prolong the PFS, but it does not benefit the OS. We established a simple and effective prognostic model for ≥ 14-year-old patients with ALL that can provide accurate risk stratification and determine the clinical strategy.

Advances in antibody-based therapy in oncology

Monoclonal antibodies are a growing class of targeted cancer therapeutics, characterized by exquisite specificity, long serum half-life, high affinity and immune effector functions. In this review, we outline key advances in the field with a particular focus on recent and emerging classes of engineered antibody therapeutic candidates, discuss molecular structure and mechanisms of action and provide updates on clinical development and practice.

Switching from salvage chemotherapy to immunotherapy in adult B-cell acute lymphoblastic leukemia

About one-half of adults with acute B-cell lymphoblastic leukemia (B-ALL) who do not achieve molecular complete remission or who subsequently relapse are not cured by current chemo- or targeted therapies. Previously, the sole therapeutic option for such persons was a hematopoietic stem cell transplant. Recently, several immune therapies including monoclonal antibodies, bispecific T-cell engagers (BiTEs), antibody-drug conjugates (ADCs), and chimeric antigen receptor T-cells (CARs) have been shown safe and effective in this setting. In this manuscript, we summarize data on US FDA-approved immune therapies of advanced adult B-ALL including rituximab, blinatumomab, inotuzumab ozogamicin, tisagenlecleucel and brexucabtagene autoleucel. We consider the results of clinical trials focusing on efficacy, safety, and quality of life (QoL). Real-world evidence is presented as well. We also briefly discuss pharmacodynamics, pharmacokinetics, and pharmacoeconomics followed by risk-benefit analyses. Lastly, we present future directions of immune therapies for advanced B-ALL in adults.

Safety of AFM11 in the treatment of patients with B-cell malignancies: findings from two phase 1 studies

BACKGROUND

The prognosis for patients with relapsed and/or refractory (R/R) non-Hodgkin's lymphoma (NHL) or acute lymphoblastic leukaemia (ALL) remains poor, with existing treatments having significant side effects. Developed for the treatment of these cancers, AFM11 is a tetravalent, bispecific humanised recombinant antibody construct (TandAb®) designed to bind to human CD19 and CD3 and lead to the activation of T cells inducing apoptosis and killing of malignant B cells.

METHODS

Two open-label, multicentre, dose-escalation phase 1 studies evaluated the safety, pharmacokinetics and activity of AFM11 in patients with R/R CD19-positive B cell NHL (AFM11-101) and in patients with CD19 + B-precursor Philadelphia-chromosome negative ALL (AFM11-102). Adverse events (AEs) were assessed and recorded; imaging (NHL) or bone marrow assessment (ALL) were used to evaluate response. Additional pharmacodynamic assays undertaken included cytokine release analysis and B-cell and T-cell depletion.

RESULTS

In AFM11-101, 16 patients with R/R NHL received AFM11 in five different dose cohorts. Of which, 14 experienced drug-related treatment-emergent AEs (TEAEs) [including five serious AEs (SAEs)], five patients experienced dose-limiting toxicity (DLT) and ten patients discontinued the study. The high number of neurological events led to a decrease in infusion frequency during the study. No objective response to treatment was observed. In AFM11-102, 17 patients with R/R ALL received AFM11 in six different dose cohorts. Thirteen patients experienced drug-related TEAEs (including four SAEs), DLTs occurred in two patients and five patients discontinued the study. An objective response was recorded in three patients. The maximum tolerated dose could not be determined in either study due to early termination.

CONCLUSIONS

AFM11 treatment was associated with frequent neurological adverse reactions that were severe in some patients. In ALL, some signs of activity, albeit short-lived, were observed whereas no activity was observed in patients with NHL; therefore, further clinical development was terminated.

TRIAL REGISTRATION

NCT02106091 . Safety Study to Assess AFM11 in Patients With Relapsed and/or Refractory CD19 Positive B-cell NHL. Registered April 2014. NCT02848911 . Safety Study to Assess AFM11 in Patients With Relapsed or Refractory Adult B-precursor ALL. Registered July 2016.

Blinatumomab in Relapsed/Refractory Burkitt Lymphoma

In patients with relapsed/refractory Burkitt lymphoma (r/r BL), overall survival (OS) is poor, and effective therapies and evidence for the best therapy are lacking. The monoclonal antibody blinatumomab may represent a novel option. However, only limited data on the use of blinatumomab in r/r BL are so far available. This multi-center, retrospective case series investigated nine patients with r/r BL treated with blinatumomab. The safety of blinatumomab was assessed with respect to frequency and severity of adverse effects (AEs) infections, cytokine release syndrome (CRS) and neurotoxicity. Progression-free survival (PFS), OS and overall response rate (ORR) were analyzed to assess efficacy. No AEs > grade 2 occurred, and AEs were generally treatable and fully reversible. The best response to blinatumomab was complete remission in 3/9 patients and partial remission in 2/9, whilst 4/9 presented with progressive disease. Median PFS and OS were 2 and 6 months, respectively, ranging from 5 days to 32 months and 11 days to 32 months, respectively. Blinatumomab treatment was a successful bridging treatment to stem cell transplantation in 3/9 patients. The response to blinatumomab varied widely, and only one patient survived longer term, but activity in patients with r/r BL was evident in some patients, with its use being safe, warranting its prospective investigation.

Considerations for design, manufacture, and delivery for effective and safe T-cell engager therapies

T-cell engager (TCE) molecules provide a targeted immunotherapy approach to treat hematologic malignancies and solid tumors. Since the approval of the CD19-targeted BiTE® (bispecific T-cell engager) molecule blinatumomab, multiple TCE molecules against different targets have been developed in several tumor types, with the approval of three additional TCE molecules in 2022. Some of the initial challenges, such as the need for continuous intravenous administration and low productivity, have been addressed in subsequent iterations of the platform by advancing half-life extended, Fc-based molecules. As clinical data from these molecules emerge, additional optimization of formats and manufacturability will be necessary. Ongoing efforts are focused on further improving TCE efficacy, safety, and convenience of administration.

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.

Therapeutic Advances in Immunotherapies for Hematological Malignancies

Following the success of immunotherapies such as chimeric antigen receptor transgenic T-cell (CAR-T) therapy, bispecific T-cell engager therapy, and immune checkpoint inhibitors in the treatment of hematologic malignancies, further studies are underway to improve the efficacy of these immunotherapies and to reduce the complications associated with their use in combination with other immune checkpoint inhibitors and conventional chemotherapy. Studies of novel therapeutic strategies such as bispecific (tandem or dual) CAR-T, bispecific killer cell engager, trispecific killer cell engager, and dual affinity retargeting therapies are also underway. Because of these studies and the discovery of novel immunotherapeutic target molecules, the use of immunotherapy for diseases initially thought to be less promising to treat with this treatment method, such as acute myeloid leukemia and T-cell hematologic tumors, has become a reality. Thus, in this coming era of new transplantation- and chemotherapy-free treatment strategies, it is imperative for both scientists and clinicians to understand the molecular immunity of hematologic malignancies. In this review, we focus on the remarkable development of immunotherapies that could change the prognosis of hematologic diseases. We also review the molecular mechanisms, development processes, clinical efficacies, and problems of new agents.

The pharmacology of blinatumomab: state of the art on pharmacodynamics, pharmacokinetics, adverse drug reactions and evaluation in clinical trials

WHAT IS KNOWN AND OBJECTIVE

Bispecific drugs (BDs) belong to the family of immunotherapies along with checkpoint inhibitors and CAR-T cells. In the field of oncology, BDs are designed to simultaneously bind a tumour antigen on the one side and an antigen present on the surface of effector cells on the other. This review summarizes the information available to date on the first marketed BiTE-format bispecific antibody, blinatumomab BLINCYTO® in acute lymphoblastic leukaemia.

METHODS

A literature search was conducted in the PubMed database by including studies published in English using the term blinatumomab. Furthermore, bibliographies of selected references were also evaluated for relevant articles. Clinical trial (CT) data were retrieved from clinicaltrials.gov (ongoing trials, adverse events [AEs]) and global pharmacovigilance data were retrieved from VigiBase®.

RESULTS AND DISCUSSION

Blinatumomab is a fusion protein which consists of two single-chain variable fragments arranged in tandem: the first binds the CD19 surface antigen of all B cells and the second targets the CD3 antigen of T cells. Binding of blinatumomab to B and T cells induces apoptosis of B cells after secretion of granzymes and perforins by T cells. T-cell activation results in secretion of pro-inflammatory cytokines and upregulation of activation markers and adhesion molecules on the surface of T cells. The major CTs that led to an indication show increased overall survival with blinatumomab with better efficacy in patients in haematological remission with minimal residual disease ≥10^-3 . The major AEs are cytokine release syndrome, neurotoxicity and hypogammaglobulinemia. The three most frequent system organ classes in CTs are haematological, gastrointestinal and general disorders. These results are also found in VigiBase® but neurological disorders and infections appear more frequently in real life.

WHAT IS NEW AND CONCLUSION

This review summarizes the current knowledge of blinatumomab in the literature. The subject of many CTs is to improve the route of administration and expand the indications for treatment.