Bispecific monoclonal antibodies for targeted immunotherapy of solid tumors: Recent advances and clinical trials

Development of a tumor-region-selective activation monoclonal antibody targeting the 4-1BB receptor for enhanced therapeutic efficacy and safety

4-1BB is a co-stimulatory immune checkpoint receptor that triggers CD8+ T cell activation, leading to robust anti-tumor responses. Although antibodies targeting 4-1BB show promise in preclinical studies, systemic 4-1BB over-activation can cause severe hepatotoxicity, limiting their clinical use. In this study, we developed Pro-Urelumab, an engineered version of the clinical anti-4-1BB antibody (Urelumab), utilizing an autologous hinge as a spatial hindrance-based antibody lock, linked the antibody and antibody lock with a matrix metalloproteinase-2/9 (MMP-2/9) substrate. This design selectively reactivates Pro-Urelumab within the tumor microenvironment, reducing systemic toxicity. Our results demonstrated that Pro-Urelumab exhibited a 389-fold reduction in binding ability toward the 4-1BB receptor compared to Urelumab, effectively preventing pro-inflammatory cytokine secretion from T cells. After MMP-2/9 cleavage, its agonist activity was fully restored. In a human T-cell-transfer mouse model, Pro-Urelumab avoided the 4-1BB antigen sink effect without causing organ damage. Mice treated with Pro-Urelumab exhibited 100 % survival over 14 days, while all Urelumab-treated mice succumbed to treatment-related toxicity. Additionally, Pro-Urelumab achieved 77 % tumor growth inhibition (TGI), compared to 45 % with Urelumab, and significantly increased T cell activation within the tumor. This study underscores the potential of tumor-selective 4-1BB activation for enhancing both the efficacy and safety of immuno-oncology therapies.

Bispecific antibodies (bsAbs) directed against PD-1/PD-L1 and CTLA-4; a mini review

Novel approaches to tumor immunotherapy include adoptive cell immunotherapy, immune checkpoint inhibitors (ICIs), and bispecific antibodies (bsABs). bsABs are members of the antibody family that have the ability to distinguish between two distinct antigens or epitopes on a single antigen. These antibodies show better clinical results than monoclonal antibodies, suggesting that they might be a useful choice for tumor immunotherapy. Additionally, dual blockade immunotherapy targeting PD-1/PD-L1 and CTLA-4 functions at various phases of T cell activation with synergistically increasing immune responses against cancer cells, in contrast to ICI monotherapy, which sometimes displays treatment resistance and limited effectiveness. It has been shown that immune response rates and anti-tumor effects may be increased in a synergistic manner by ICI-based combination therapy. We explore the safety and effectiveness of bsABs and ICIs (especially PD1/PDL1 and CTLA-4) combination treatments in tumor immunotherapy in this study with the goal of offering evidence-based methods for clinical research and tailored tumor identification and management.

Trends and challenges in bispecific antibody production

Bispecific antibodies (bsAbs) represent a rapidly growing field of therapeutic agents. More bsAbs are being approved worldwide and are in various stages of clinical trials. However, the discovery and production of novel bsAbs presents significant challenges due to their complex structure. Thus, precise control of assembly and stability is required, given the many formats developed. This review examines recent trends in bsAb production, focusing on advancements in engineering platforms, production strategies, and challenges in large-scale manufacturing. Key developments include improvements in modular antibody design, novel expression systems, and optimization of bioprocessing techniques to enhance stability, yield, and efficacy. Additionally, the article explores the future potential of bsAbs as next-generation therapeutics, underscoring the growing impact of these innovations on expanding treatment options for patients with unmet medical needs.

Seaweed-derived laminarin and alginate as potential chemotherapeutical agents: An updated comprehensive review considering cancer treatment

Seaweed-derived bioactive substances such as polysaccharides have proven to be effective chemotherapeutic and chemopreventive agents. Laminarin and alginate antioxidant properties aid in the prevention of cancer through dynamic modulation of critical intracellular signaling pathways via apoptosis which produce low cytotoxicity and potential chemotherapeutic effects. Understanding the effects of laminarin and alginate on human cancer cells and their molecular roles in cell death pathways can help to develop a novel chemoprevention strategy. This review emphasizes the importance of apoptosis-modulating laminarin and alginate in a range of malignancies as well as their extraction, molecular structure, and weight. In addition, future nano-formulation enhancements for greater clinical efficacy are discussed. Laminarin and alginate are perfect ingredients because of their distinct physicochemical and biological characteristics and their use-based delivery systems in cancer. The effectiveness of laminarin and alginate against cancer and more preclinical and clinical trials will open up as new chemotherapeutic natural drugs which lead to established as potential cancer drugs.

In vivo self-assembled bispecific fluorescence probe for early detection of bladder cancer and metastasis

Tumor metastasis accounts for over 90% of tumor-related deaths, prompting the development of fluorescently labeled tumor-specific molecular imaging agents for differentiating tumors from normal tissues. However, early detection of metastasis lesions by tracking tumor markers alone has proven to be challenging. Herein, we reported a glycopeptide-based bispecific fluorescence probe (bsProbe) for earlier detection of bladder cancer and metastasis. By simultaneously recognition (tumor & tumor microenvironment) and in vivo self-assembly, the tumor accumulation of bsProbe (12.3% ID/g) was obviously increased by ∼6 fold compared with that in CXCR4 specific fluorescence probe (sProbe), indicating the obvious advantages of bsProbe over existing tumor metastasis detection probes. Additionally, bsProbe substantially broadens the tumor diagnosis window and enhances the detection signal to noise ratio (SNR: approximately 9.5), permitting early diagnosis of lung micro-metastasis (∼1 mm), precise identifying of tumor boundaries and micro-tumors in orthotopic tumor models. More importantly, bsProbe was demonstrated to distinguish malignant from benign specimen with a specificity of 90.48% and sensitivity of 92.22% in 195 clinical specimens of bladder cancer patients. Taken together, this novel synergetic targeting (CD206 × CXCR4) strategy provides an attractive method for earlier detection of bladder cancer and metastasis, which might be further extended to the imaging-guided surgery of clinical invisible tumors.

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.

Present and future of cancer nano-immunotherapy: opportunities, obstacles and challenges

Clinically, multimodal therapies are adopted worldwide for the management of cancer, which continues to be a leading cause of death. In recent years, immunotherapy has firmly established itself as a new paradigm in cancer care that activates the body's immune defense to cope with cancer. Immunotherapy has resulted in significant breakthroughs in the treatment of stubborn tumors, dramatically improving the clinical outcome of cancer patients. Multiple forms of cancer immunotherapy, including immune checkpoint inhibitors (ICIs), adoptive cell therapy and cancer vaccines, have become widely available. However, the effectiveness of these immunotherapies is not much satisfying. Many cancer patients do not respond to immunotherapy, and disease recurrence appears to be unavoidable because of the rapidly evolving resistance. Moreover, immunotherapies can give rise to severe off-target immune-related adverse events. Strategies to remove these hindrances mainly focus on the development of combinatorial therapies or the exploitation of novel immunotherapeutic mediations. Nanomaterials carrying anticancer agents to the target site are considered as practical approaches for cancer treatment. Nanomedicine combined with immunotherapies offers the possibility to potentiate systemic antitumor immunity and to facilitate selective cytotoxicity against cancer cells in an effective and safe manner. A myriad of nano-enabled cancer immunotherapies are currently under clinical investigation. Owing to gaps between preclinical and clinical studies, nano-immunotherapy faces multiple challenges, including the biosafety of nanomaterials and clinical trial design. In this review, we provide an overview of cancer immunotherapy and summarize the evidence indicating how nanomedicine-based approaches increase the efficacy of immunotherapies. We also discuss the key challenges that have emerged in the era of nanotechnology-based cancer immunotherapy. Taken together, combination nano-immunotherapy is drawing increasing attention, and it is anticipated that the combined treatment will achieve the desired success in clinical cancer therapy.

A Comprehensive Review of the Mechanisms and Clinical Development of Monoclonal Antibodies in Cancer Therapy

Cancer is still the disease that ranks first in human mortality in the twenty-first century. In the last 20 years, the concept of molecular targeted therapy has come to the fore with the use of small molecule agents or signal transduction inhibitors that show anticancer effects for certain types of cancer. Monoclonal antibodies, which have a therapeutic effect, especially by providing signal transduction inhibition, are used clinically as first-line treatment in various types of cancer. Molecular targeted therapies are critical for eliminating the adverse effects and drug resistance problems that occur in traditional cancer treatments. This review summarizes current information on various targeted therapeutic agents, including the structure and classification of monoclonal antibodies, their production methods and mechanisms of action, the monoclonal antibodies used in clinical trials, the complement system mechanism and cancer relationship, and the relationship between complement-dependent cytotoxicity and monoclonal antibodies.

Comparative Analysis of Bispecific Antibodies and CAR T-Cell Therapy in Follicular Lymphoma

The treatment landscape for relapsed/refractory follicular lymphoma (RR-FL) is marked by a pivotal debate between chimeric antigen receptor T-cell (CAR-T) therapy and bispecific antibodies (BsAbs). While both CAR-T therapy and BsAbs target similar immunobiology and molecular markers, their efficacy comparisons are hindered by the lack of direct clinical trial comparisons. Key trials, such as the ZUMA-5 study, underscore axicabtagene ciloleucel (axi-cel)'s efficacy in treating RR-FL, achieving a 79% complete response rate with a median duration of response exceeding 3 years. Similarly, lisocabtagene maraleucel (liso-cel) in the TRANSCEND FL study reports a 94% complete response rate, emphasizing robust outcomes in heavily pretreated patients. Among BsAbs, mosunetuzumab showed promise in the GO29781 trial, with a 62% overall response rate in heavily pretreated RR-FL patients. Thus, CAR-T therapy offers potential curative benefits with a single infusion. However, its efficacy is tempered by significant adverse events such as cytokine release syndrome (CRS), neurotoxicity, and cytopenias, requiring specialized management and patient monitoring. In contrast, BsAbs provide a more tolerable treatment option counterbalancing by lower response rates and frequent dosing requirements. Personalized treatment strategies are crucial because of these distinct efficacy and safety profiles. When considering cost-effectiveness, both therapies need to be evaluated in the context of their clinical outcomes and quality of life improvements. Cost-effectiveness considerations are essential; while CAR-T therapies incur higher initial costs, their potential for long-term remission may mitigate expenses associated with repeated treatments or hospitalizations. Future research into resistance mechanisms and optimal therapeutic sequencing will further refine RR-FL management strategies.

A study on the efficacy and Safety Evaluation of a novel PD-1/CTLA-4 bispecific antibody

Tumors constitute a significant health concern for humans, and PD-1 and CTLA-4 monoclonal antibodies have been proven effective in cancer treatment. Some researchers have identified that the combination of PD-1 and CTLA-4 dual blockade demonstrates superior therapeutic efficacy. However, the development of PD-1/CTLA-4 bispecific antibodies faces challenges in terms of both safety and efficacy. The present study discloses a novel PD-1/CTLA-4 bispecific antibody, designated as SH010. Experimental validation through surface plasmon resonance (SPR) confirmed that SH010 exhibits favorable binding activity with both PD-1 and CTLA-4. Flow cytometry analysis demonstrated stable binding of SH010 antibody to CHOK1 cells overexpressing human or cynomolgus monkey PD-1 protein and to 293F cells overexpressing human or cynomolgus monkey CTLA-4 protein. Moreover, it exhibited excellent blocking capabilities in protein binding between human PD-1 and PD-L1, as well as human CTLA-4 and CD80/CD86. Simultaneously, in vitro experiments indicate that SH010 exerts a significant activating effect on hPBMCs. In murine transplant models of human prostate cancer (22RV1) and small cell lung cancer (NCI-H69), administration of varying concentrations of the bispecific antibody significantly inhibits tumor growth. MSD analysis revealed that stimulation of hPBMCs from three different donors with SH010 did not induce the production of cytokine release syndrome. Furthermore, Single or repeated intravenous administrations of SH010 in cynomolgus monkeys show favorable systemic exposure without noticeable drug accumulation or apparent toxicity. In conclusion, SH010 represents a novel cancer therapeutic drug poised to enter clinical trials and obtain market approval.

Plonmarlimab, a novel anti-GM-CSF blocking antibody, ameliorates disease progression in the pre-clinical model of macrophage activation syndrome

OBJECTIVES

We aimed to characterize and investigate the safety and efficacy of Plonmarlimab, a novel anti-granulocyte-macrophage colony-stimulating factor (anti-GM-CSF) neutralizing antibody, on the treatment of macrophage activation syndrome (MAS), a life-threatening systemic inflammatory disease, in pre-clinical models.

METHODS

The binding affinity was evaluated using Biacore. The neutralizing activity was measured through the blockade of ligand-receptor interaction, inhibition of STAT5 phosphorylation and suppression of TF-1 cell proliferation. The efficacy of Plonmarlimab was evaluated in a humanized MAS model, which was established by engrafting human umbilical cord blood (UCB) cells into NOG-EXL mice. Additionally, the safety profile of Plonmarlimab was investigated in cynomolgus monkeys.

RESULTS

At the molecular level, Plonmarlimab showed sub-nanomolar binding affinity with human GM-CSF and effectively blocked the binding of GM-CSF to its receptor. At the cellular level, Plonmarlimab dose-dependently inhibited intracellular STAT5 phosphorylation and suppressed GM-CSF-induced TF-1 proliferation. In the UCB-engrafted NOG-EXL MAS mouse model, Plonmarlimab treatment significantly ameliorated disease progression, demonstrated by the improvements in body weight loss, anaemia and some histopathological features. Furthermore, Plonmarlimab was well tolerated up to 150 mg/kg weekly in monkeys with no reported adverse effects.

CONCLUSIONS

Plonmarlimab is a highly potent GM-CSF blocking antibody and has demonstrated promising efficacy in a pre-clinical MAS model with a favourable safety profile, supporting its clinical development.

Tumour Immunotherapy and Applications of Immunological Products: A Review of Literature

Malignant tumors, characterized by uncontrolled cell proliferation, are a leading global health challenge, responsible for over 9.7 million deaths in 2022, with new cases expected to rise to 35 million annually by 2050. Immunotherapy is preferred to other cancer therapies, offering precise targeting of malignant cells while simultaneously strengthening the immune system's complex responses. Advances in this novel field of science have been closely linked to a deeper knowledge of tumor biology, particularly the intricate interplay between tumor cells, the immune system, and the tumor microenvironment (TME), which are central to cancer progression and immune evasion. This review offers a comprehensive analysis of the molecular mechanisms that govern these interactions, emphasizing their critical role in the development of effective immunotherapeutic products. We critically evaluate the current immunotherapy approaches, including cancer vaccines, adoptive T cell therapies, and cytokine-based treatments, highlighting their efficacy and safety. We also explore the latest advancements in combination therapies, which synergistically integrate multiple immunotherapeutic strategies to overcome resistance and enhance therapeutic outcomes. This review offers key insights into the future of cancer immunotherapy with a focus on advancing more effective and personalized treatment strategies.

Chemical Production of Cytotoxic Bispecific Antibodies Using the Ugi Multicomponent Reaction

Bispecific antibodies (bsAbs) have recently emerged as a promising platform for the treatment of several conditions, most importantly cancer. Based on the combination of two different antigen-binding motifs in a single macromolecule; bsAbs can either display the combined characteristics of their parent antibodies, or new therapeutic features, inaccessible by the sole combination of two distinct antibodies. While bsAbs are traditionally produced by molecular biology techniques, the chemical development of bsAbs holds great promises and strategies have just begun to surface. In this context, we took advantage of a chemical strategy based on the use of the Ugi reaction for the site-selective conjugation of whole antibodies and coupled the resulting conjugates in a bioorthogonal manner with Fab fragments, derived from various antibodies. We thus managed to produce five different bsAbs with 2 : 1 valency, with yields ranging from 20 % to 48 %, and showed that the affinity of the parent antibody was preserved in all bsAbs. We further demonstrated the interest of our strategy by producing two other bsAbs behaving as cytotoxic T cell engagers with IC50 values in the picomolar range in vitro.

A novel bispecific peptide targeting PD-1 and PD-L1 with combined antitumor activity of T-cells derived from the patients with TSCC

Programmed death-1 (PD-1) and programmed death ligand-1 (PD-L1) are key immune checkpoints (ICs) that critically influence immunotherapy. Tumor resistance to single IC-targeting drugs has increased interest in dual-target drugs, which have shown feasibility for cancer treatment. In this study, we aimed to develop dual-target peptide drugs targeting the PD-1/PD-L1 pathway and to evaluate their efficacy compared to functional antibodies in enhancing the cytotoxicity of human T cells against tongue squamous carcinoma cell lines. Through sequence analysis and peptide truncation, we modified a pre-existing peptide named nABPD-1 targeting PD-1. Subsequently, we obtained two novel peptides named nABPD-2 and nABPD-3, with nABPD-2 showing an enhanced affinity for human PD-1 protein compared to nABPD-1. Importantly, nABPD-2 exhibited dual-targeting capability, possessing a high affinity for both PD-L1 and PD-1. Furthermore, nABPD-2 effectively promoted the cytotoxicity of human T cells against tongue squamous carcinoma cell lines, surpassing the efficacy of anti-PD-1 or anti-PD-L1 functional antibodies alone. Considering that nABPD-2 has lower production costs and dose requirements, it can potentially be used in therapeutic applications.

Impact of fed-batch process intensification on the productivity and product quality of two CHO cell lines expressing unique novel molecular format proteins

While monospecific antibodies have long been the foundational offering of protein therapeutics, recent advancements in antibody engineering have allowed for the development of far more complex antibody structures. Novel molecular format (NMF) proteins, such as bispecific antibodies (BsAbs), are structures capable of multispecific binding, allowing for expanded therapeutic functionality. As demand for NMF proteins continues to rise, biomanufacturers face the challenge of increasing bioreactor process productivity while simultaneously maintaining consistent product quality. This challenge is exacerbated when producing structurally complex proteins with asymmetric modalities, as seen in NMFs. In this study, the impact of a high inoculation density (HID) fed-batch process on the productivity and product quality attributes of two CHO cell lines expressing unique NMFs, a monospecific antibody with an Fc-fusion protein and a bispecific antibody, compared to low inoculation density (LID) platform fed-batch processes was evaluated. It was observed that an intensified platform fed-batch process increased product concentrations by 33 and 109% for the two uniquely structured complex proteins in a shorter culture duration while maintaining similar product quality attributes to traditional fed-batch processes.

Antibody-drug conjugates in cancer therapy: mechanisms and clinical studies

Antibody-drug conjugates (ADCs) consist of monoclonal antibodies that target tumor cells and cytotoxic drugs linked through linkers. By leveraging antibodies' targeting properties, ADCs deliver cytotoxic drugs into tumor cells via endocytosis after identifying the tumor antigen. This precise method aims to kill tumor cells selectively while minimizing harm to normal cells, offering safe and effective therapeutic benefits. Recent years have seen significant progress in antitumor treatment with ADC development, providing patients with new and potent treatment options. With over 300 ADCs explored for various tumor indications and some already approved for clinical use, challenges such as resistance due to factors like antigen expression, ADC processing, and payload have emerged. This review aims to outline the history of ADC development, their structure, mechanism of action, recent composition advancements, target selection, completed and ongoing clinical trials, resistance mechanisms, and intervention strategies. Additionally, it will delve into the potential of ADCs with novel markers, linkers, payloads, and innovative action mechanisms to enhance cancer treatment options. The evolution of ADCs has also led to the emergence of combination therapy as a new therapeutic approach to improve drug efficacy.

HER3 receptor and its role in the therapeutic management of metastatic breast cancer

Metastatic breast cancer (mBC) poses a significant threat to women's health and is a major cause of malignant neoplasms in women. Human epidermal growth factor receptor (HER)3, an integral member of the ErbB/HER receptor tyrosine kinase family, is a crucial activator of the phosphoinositide-3 kinase/protein kinase B signaling pathway. HER3 overexpression significantly contributes to the development of resistance to drugs targeting other HER receptors, such as HER2 and epidermal growth factor receptors, and plays a crucial role in the onset and progression of mBC. Recently, numerous HER3-targeted therapeutic agents, such as monoclonal antibodies (mAbs), bispecific antibodies (bAbs), and antibody-drug conjugates (ADCs), have emerged. However, the efficacy of HER3-targeted mAbs and bAbs is limited when used individually, and their combination may result in toxic adverse effects. On the other hand, ADCs are cytotoxic to cancer cells and can bind to target cells through antibodies, which highlights their use in targeted HER3 therapy for mBC. This review provides an overview of recent advancements in HER3 research, historical initiatives, and innovative approaches in targeted HER3 therapy for metastatic breast cancer. Evaluating the advantages and disadvantages of current methods may yield valuable insights and lessons.

Pharmacist perspectives on emerging T cell-engaging bispecific therapies in cancer therapeutics

PURPOSE

To summarize the pharmacology, efficacy, safety, dosing, administration, and pharmacist perspectives related to operationalization of new and emerging bispecific therapies indicated for the treatment of various cancers.

SUMMARY

In recent years, there have been significant advancements in the expansion of immunotherapeutics in the treatment of various malignancies. Bispecific T cell-engaging therapies represent an emerging therapeutic drug class for the treatment of cancer. These therapies are unique antibody constructs that bind simultaneously to 2 targets, a tumor-specific antigen and CD3 on T cells, to elicit an immune response. Recently, several bispecific therapies have been approved, including epcoritamab, glofitamab, mosunetuzumab, tebentafusp, and teclistamab. Epcoritamab and glofitamab have been approved for diffuse large B cell lymphoma, while mosunetuzumab, tebentafusp, and teclistamab have been approved for follicular lymphoma, uveal melanoma, and multiple myeloma, respectively. As a result of their mechanism of action, the approved bispecific therapies have the potential to cause cytokine release syndrome, and, along with this, they all have unique and specific monitoring parameters and operational considerations that require clinician awareness when administering these therapies. Such operational challenges include within-patient dose escalations at therapy initiation, hospitalization for monitoring, and various pharmacological strategies for prophylaxis of cytokine release syndrome.

CONCLUSION

Bispecific therapies have continued to evolve the therapeutic landscape of cancer, primarily in hematological malignancies. Health-system pharmacists have the opportunity to play a key role in the operationalization and management of this new and emerging drug class.

Immunotherapies for locally aggressive cancers

Improving surgical resection outcomes for locally aggressive tumors is key to inducing durable locoregional disease control and preventing progression to metastatic disease. Macroscopically complete resection of the tumor is the standard of care for many cancers, including breast, ovarian, lung, sarcoma, and mesothelioma. Advancements in cancer diagnostics are increasing the number of surgically eligible cases through early detection. Thus, a unique opportunity arises to improve patient outcomes with decreased recurrence rates via intraoperative delivery treatments using local drug delivery strategies after the tumor has been resected. Of the current systemic treatments (e.g., chemotherapy, targeted therapies, and immunotherapies), immunotherapies are the latest approach to offer significant benefits. Intraoperative strategies benefit from direct access to the tumor microenvironment which improves drug uptake to the tumor and simultaneously minimizes the risk of drug entering healthy tissues thereby resulting in fewer or less toxic adverse events. We review the current state of immunotherapy development and discuss the opportunities that intraoperative treatment provides. We conclude by summarizing progress in current research, identifying areas for exploration, and discussing future prospects in sustained remission.

Epidermal Growth Factor Receptor Targeting in Colorectal Carcinoma: Antibodies and Patient-Derived Organoids as a Smart Model to Study Therapy Resistance

Colorectal cancer (CRC) is the second leading cause of cancer-related death worldwide. Therefore, the need for new therapeutic strategies is still a challenge. Surgery and chemotherapy represent the first-line interventions; nevertheless, the prognosis for metastatic CRC (mCRC) patients remains unacceptable. An important step towards targeted therapy came from the inhibition of the epidermal growth factor receptor (EGFR) pathway, by the anti-EGFR antibody, Cetuximab, or by specific tyrosine kinase inhibitors (TKI). Cetuximab, a mouse-human chimeric monoclonal antibody (mAb), binds to the extracellular domain of EGFR thus impairing EGFR-mediated signaling and reducing cell proliferation. TKI can affect the EGFR biochemical pathway at different steps along the signaling cascade. Apart from Cetuximab, other anti-EGFR mAbs have been developed, such as Panitumumab. Both antibodies have been approved for the treatment of KRAS-NRAS wild type mCRC, alone or in combination with chemotherapy. These antibodies display strong differences in activating the host immune system against CRC, due to their different immunoglobulin isotypes. Although anti-EGFR antibodies are efficient, drug resistance occurs with high frequency. Resistant tumor cell populations can either already be present before therapy or develop later by biochemical adaptations or new genomic mutations in the EGFR pathway. Numerous efforts have been made to improve the efficacy of the anti-EGFR mAbs or to find new agents that are able to block downstream EGFR signaling cascade molecules. Indeed, we examined the importance of analyzing the anti-EGFR antibody-drug conjugates (ADC) developed to overcome resistance and/or stimulate the tumor host's immunity against CRC growth. Also, patient-derived CRC organoid cultures represent a useful and feasible in vitro model to study tumor behavior and therapy response. Organoids can reflect tumor genetic heterogeneity found in the tissue of origin, representing a unique tool for personalized medicine. Thus, CRC-derived organoid cultures are a smart model for studying the tumor microenvironment and for the preclinical assay of anti-EGFR drugs.

Role of immunotherapies and stem cell therapy in the management of liver cancer: A comprehensive review

Liver cancer (LC) is the sixth most common disease and the third most common cause of cancer-related mortality. The WHO predicts that more than 1 million deaths will occur from LC by 2030. Hepatocellular carcinoma (HCC) is a common form of primary LC. Today, the management of LC involves multiple disciplines, and multimodal therapy is typically selected on an individual basis, considering the intricate interactions between the patient's overall health, the stage of the tumor, and the degree of underlying liver disease. Currently, the treatment of cancers, including LC, has undergone a paradigm shift in the last ten years because of immuno-oncology. To treat HCC, immune therapy approaches have been developed to enhance or cause the body's natural immune response to specifically target tumor cells. In this context, immune checkpoint pathway inhibitors, engineered cytokines, adoptive cell therapy, immune cells modified with chimeric antigen receptors, and therapeutic cancer vaccines have advanced to clinical trials and offered new hope to cancer patients. The outcomes of these treatments are encouraging. Additionally, treatment using stem cells is a new approach for restoring deteriorated tissues because of their strong differentiation potential and capacity to release cytokines that encourage cell division and the formation of blood vessels. Although there is no proof that stem cell therapy works for many types of cancer, preclinical research on stem cells has shown promise in treating HCC. This review provides a recent update regarding the impact of immunotherapy and stem cells in HCC and promising outcomes.

Treatment Options for Hepatocellular Carcinoma Using Immunotherapy: Present and Future

Hepatocellular carcinoma (HCC) is a common cancer, and the body's immune responses greatly affect its progression and the prognosis of patients. Immunological suppression and the maintenance of self-tolerance in the tumor microenvironment are essential responses, and these form part of the theoretical foundations of immunotherapy. In this review, we first discuss the tumor microenvironment of HCC, describe immunosuppression in HCC, and review the major biomarkers used to track HCC progression and response to treatment. We then examine antibody-based therapies, with a focus on immune checkpoint inhibitors (ICIs), monoclonal antibodies that target key proteins in the immune response (programmed cell death protein 1, anti-cytotoxic T-lymphocyte associated protein 4, and programmed death-ligand 1) which have transformed the treatment of HCC and other cancers. ICIs may be used alone or in conjunction with various targeted therapies for patients with advanced HCC who are receiving first-line treatments or subsequent treatments. We also discuss the use of different cellular immunotherapies, including T cell receptor (TCR) T cell therapy and chimeric antigen receptor (CAR) T cell therapy. We then review the use of HCC vaccines, adjuvant immunotherapy, and oncolytic virotherapy, and describe the goals of future research in the development of treatments for HCC.

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.

Introduction of Carbonyl Groups into Antibodies

Antibodies and their derivatives (scFv, Fabs, etc.) represent a unique class of biomolecules that combine selectivity with the ability to target drug delivery. Currently, one of the most promising endeavors in this field is the development of molecular diagnostic tools and antibody-based therapeutic agents, including antibody-drug conjugates (ADCs). To meet this challenge, it is imperative to advance methods for modifying antibodies. A particularly promising strategy involves the introduction of carbonyl groups into the antibody that are amenable to further modification by biorthogonal reactions, namely aliphatic, aromatic, and α-oxo aldehydes, as well as aliphatic and aryl-alkyl ketones. In this review, we summarize the preparation methods and applications of site-specific antibody conjugates that are synthesized using this approach.

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.

Cellular Membrane Components-Mediated Cancer Immunotherapeutic Platforms

Immune cell engineering is an active field of ongoing research that can be easily applied to nanoscale biomedicine as an alternative to overcoming limitations of nanoparticles. Cell membrane coating and artificial nanovesicle technology have been reported as representative methods with an advantage of good biocompatibility for biomimetic replication of cell membrane characteristics. Cell membrane-mediated biomimetic technique provides properties of natural cell membrane and enables membrane-associated cellular/molecular signaling. Thus, coated nanoparitlces (NPs) and artificial nanovesicles can achieve effective and extended in vivo circulation, enabling execution of target functions. While coated NPs and artificial nanovesicles provide clear advantages, much work remains before clinical application. In this review, first a comprehensive overview of cell membrane coating techniques and artificial nanovesicles is provided. Next, the function and application of various immune cell membrane types are summarized.

Therapeutic Antibodies in Medicine

Antibody engineering has developed into a wide-reaching field, impacting a multitude of industries, most notably healthcare and diagnostics. The seminal work on developing the first monoclonal antibody four decades ago has witnessed exponential growth in the last 10-15 years, where regulators have approved monoclonal antibodies as therapeutics and for several diagnostic applications, including the remarkable attention it garnered during the pandemic. In recent years, antibodies have become the fastest-growing class of biological drugs approved for the treatment of a wide range of diseases, from cancer to autoimmune conditions. This review discusses the field of therapeutic antibodies as it stands today. It summarizes and outlines the clinical relevance and application of therapeutic antibodies in treating a landscape of diseases in different disciplines of medicine. It discusses the nomenclature, various approaches to antibody therapies, and the evolution of antibody therapeutics. It also discusses the risk profile and adverse immune reactions associated with the antibodies and sheds light on future applications and perspectives in antibody drug discovery.

How can Cytokine-induced killer cells overcome CAR-T cell limits

The successful treatment of patients affected by B-cell malignancies with Chimeric Antigen Receptor (CAR)-T cells represented a breakthrough in the field of adoptive cell therapy (ACT). However, CAR-T therapy is not an option for every patient, and several needs remain unmet. In particular, the production of CAR-T cells is expensive, labor-intensive and logistically challenging; additionally, the toxicities deriving from CAR-T cells infusion, such as cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS), have been documented extensively. Alternative cellular therapy products such as Cytokine-induced killer (CIK) cells have the potential to overcome some of these obstacles. CIK cells are a heterogeneous population of polyclonal CD3+CD56+ T cells with phenotypic and functional properties of NK cells. CIK cell cytotoxicity is exerted in a major histocompatibility complex (MHC)-unrestricted manner through the engagement of natural killer group 2 member D (NKG2D) molecules, against a wide range of hematological and solid tumors without the need for prior antigen exposure or priming. The foremost potential of CIK cells lies in the very limited ability to induce graft-versus-host disease (GvHD) reactions in the allogeneic setting. CIK cells are produced with a simple and extremely efficient expansion protocol, which leads to a massive expansion of effector cells and requires a lower financial commitment compared to CAR-T cells. Indeed, CAR-T manufacturing involves the engineering with expensive GMP-grade viral vectors in centralized manufacturing facilities, whereas CIK cell production is successfully performed in local academic GMP facilities, and CIK cell treatment is now licensed in many countries. Moreover, the toxicities observed for CAR-T cells are not present in CIK cell-treated patients, thus further reducing the costs associated with hospitalization and post-infusion monitoring of patients, and ultimately encouraging the delivery of cell therapies in the outpatient setting. This review aims to give an overview of the limitations of CAR-T cell therapy and outline how the use of CIK cells could overcome such drawbacks thanks to their unique features. We highlight the undeniable advantages of using CIK cells as a therapeutic product, underlying the opportunity for further research on the topic.

A neutralizing bispecific single-chain antibody against SARS-CoV-2 Omicron variant produced based on CR3022

Introduction

The constantly mutating SARS-CoV-2 has been infected an increasing number of people, hence the safe and efficacious treatment are urgently needed to combat the COVID-19 pandemic. Currently, neutralizing antibodies (Nabs), targeting the receptor-binding domain (RBD) of the SARS-CoV-2 spike protein are potentially effective therapeutics against COVID-19. As a new form of antibody, bispecific single chain antibodies (BscAbs) can be easily expressed in E. coli and exhibits broad-spectrum antiviral activity.

Methods

In this study, we constructed two BscAbs 16-29, 16-3022 and three single chain variable fragments (scFv) S1-16, S2-29 and S3022 as a comparison to explore their antiviral activity against SARS-CoV-2. The affinity of the five antibodies was characterized by ELISA and SPR and the neutralizing activity of them was analyzed using pseudovirus or authentic virus neutralization assay. Bioinformatics and competitive ELISA methods were used to identify different epitopes on RBD.

Results

Our results revealed the potent neutralizing activity of two BscAbs 16-29 and 16-3022 against SARS-CoV-2 original strain and Omicron variant infection. In addition, we also found that SARS-CoV RBD-targeted scFv S3022 could play a synergistic role with other SARS-CoV-2 RBD-targeted antibodies to enhance neutralizing activity in the form of a BscAb or in cocktail therapies.

Discussion

This innovative approach offers a promising avenue for the development of subsequent antibody therapies against SARSCoV-2. Combining the advantages of cocktails and single-molecule strategies, BscAb therapy has the potential to be developed as an effective immunotherapeutic for clinical use to mitigate the ongoing pandemic.

T cell-dependent bispecific antibodies alter organ-specific endothelial cell-T cell interaction

Preclinical and clinical studies demonstrate that T cell-dependent bispecific antibodies (TDBs) induce systemic changes in addition to tumor killing, leading to adverse events. Here, we report an in-depth characterization of acute responses to TDBs in tumor-bearing mice. Contrary to modest changes in tumors, rapid and substantial lymphocyte accumulation and endothelial cell (EC) activation occur around large blood vessels in normal organs including the liver. We hypothesize that organ-specific ECs may account for the differential responses in normal tissues and tumors, and we identify a list of genes selectively upregulated by TDB in large liver vessels. Using one of the genes as an example, we demonstrate that CD9 facilitates ICAM-1 to support T cell-EC interaction in response to soluble factors released from a TDB-mediated cytotoxic reaction. Our results suggest that multiple factors may cooperatively promote T cell infiltration into normal organs as a secondary response to TDB-mediated tumor killing. These data shed light on how different vascular beds respond to cancer immunotherapy and may help improve their safety and efficacy.

Immunotherapy for hepatocellular carcinoma: Current status and future perspectives

Hepatocellular carcinoma (HCC) is one of the world’s deadliest and fastest-growing tumors, with a poor prognosis. HCC develops in the context of chronic liver disease. Curative resection, surgery (liver transplantation), trans-arterial chemoembolization, radioembolization, radiofrequency ablation and chemotherapy are common treatment options for HCC, however, they will only assist a limited percentage of patients. Current treatments for advanced HCC are ineffective and aggravate the underlying liver condition. Despite promising preclinical and early-phase clinical trials for some drugs, existing systemic therapeutic methods for advanced tumor stages remain limited, underlining an unmet clinical need. In current years, cancer immunotherapy has made significant progress, opening up new treatment options for HCC. HCC, on the other hand, has a variety of causes and can affects the body’s immune system via a variety of mechanisms. With the speedy advancement of synthetic biology and genetic engineering, a range of innovative immunotherapies, such as immune checkpoint inhibitors [anti-programmed cell death-1 (PD-1), anti-cytotoxic T lymphocyte antigen-4, and anti-PD ligand 1 cell death antibodies], therapeutic cancer vaccines, engineered cytokines, and adoptive cell therapy have all been used for the treatment of advanced HCC. In this review, we summarize the present clinical and preclinical landscape of immunotherapies in HCC, critically discuss recent clinical trial outcomes, and address future perspectives in the field of liver cancer.

eIg-based bispecific T-cell engagers targeting EGFR: Format matters

Bispecific antibodies are molecules with versatile modes of action and applications for therapy. They are commonly developed as T-cell engagers (TCE), which simultaneously target an antigen expressed by tumor cells and CD3 expressed by T-cells, thereby inducing T-cell-mediated target cell killing. There is growing evidence that the molecular composition and valency for the target antigen influence the activity of TCEs. Here, the eIg platform technology was used to generate a set of bispecific TCEs targeting epidermal growth factor receptors (EGFR) and CD3. These molecules either included or lacked an Fc region and exhibited one binding site for CD3 and either one or two binding sites for EGFR (1 + 1 or 2 + 1 formats) utilizing different molecular arrangements of the binding sites. In total, 11 different TCE formats were analyzed for binding to target cells and T cells, T cell-mediated killing of tumor cells, and for the activation of T cells (release of cytokines and proliferation of T-cells). Bivalent binding to EGFR strongly increased binding and T cell-mediated killing. However, the molecular composition and position of the CD3-binding arm also affected target cell killing, cytokine release, and T-cell proliferation. Our findings support that screening of a panel of formats is beneficial to identify the most potent bispecific TCE, and that format matters.

Bispecific Antibodies: A Novel Approach for the Treatment of Solid Tumors

Advancement in sequencing technologies allows for the identification of molecular pathways involved in tumor progression and treatment resistance. Implementation of novel agents targeting these pathways, defined as targeted therapy, significantly improves the prognosis of cancer patients. Targeted therapy also includes the use of monoclonal antibodies (mAbs). These drugs recognize specific oncogenic proteins expressed in cancer cells. However, as with many other types of targeting agents, mAb-based therapy usually fails in the long-term control of cancer progression due to the development of resistance. In many cases, resistance is caused by the activation of alternative pathways involved in cancer progression and the development of immune evasion mechanisms. To overcome this off-target resistance, bispecific antibodies (bsAbs) were developed to simultaneously target differential oncogenic pathway components, tumor-associated antigens (TAA) and immune regulatory molecules. As a result, in the last few years, several bsAbs have been tested or are being tested in cancer patients. A few of them are currently approved for the treatment of some hematologic malignancies but no bsAbs are approved in solid tumors. In this review, we will provide an overview of the state-of-the-art of bsAbs for the treatment of solid malignancies outlining their classification, design, main technologies utilized for production, mechanisms of action, updated clinical evidence and potential limitations.

Current landscape and future directions of bispecific antibodies in cancer immunotherapy

Recent advances in cancer immunotherapy using monoclonal antibodies have dramatically revolutionized the therapeutic strategy against advanced malignancies, inspiring the exploration of various types of therapeutic antibodies. Bispecific antibodies (BsAbs) are recombinant molecules containing two different antigens or epitopes identifying binding domains. Bispecific antibody-based tumor immunotherapy has gained broad potential in preclinical and clinical investigations in a variety of tumor types following regulatory approval of newly developed technologies involving bispecific and multispecific antibodies. Meanwhile, a series of challenges such as antibody immunogenicity, tumor heterogeneity, low response rate, treatment resistance, and systemic adverse effects hinder the application of BsAbs. In this review, we provide insights into the various architecture of BsAbs, focus on BsAbs' alternative different mechanisms of action and clinical progression, and discuss relevant approaches to overcome existing challenges in BsAbs clinical application.

Monoclonal antibodies in cervical malignancy-related HPV

Despite many efforts to treat HPV infection, cervical cancer survival is still poor for several reasons, including resistance to chemotherapy and relapse. Numerous treatments such as surgery, radiation therapy, immune cell-based therapies, siRNA combined with various drugs, and immunotherapy are being studied and performed to provide the best treatment. Depending on the stage and size of the tumor, methods such as radical hysterectomy, pelvic lymphadenectomy, or chemotherapy can be utilized to treat cervical cancer. While accepted, these treatments lead to interruptions in cellular pathways and immune system homeostasis. In addition to a low survival rate, cervical neoplasm incidence has been rising significantly. However, new strategies have been proposed to increase patient survival while reducing the toxicity of chemotherapy, including targeted therapy and monoclonal antibodies. In this article, we discuss the types and potential therapeutic roles of monoclonal antibodies in cervical cancer.

Novel tri-specific tribodies induce strong T cell activation and anti-tumor effects in vitro and in vivo

Background

Immunotherapy based on Bi-specific T Cell Engagers (TCE) represents one of the most attractive strategy to treat cancers resistant to conventional therapies. TCE are antibody-like proteins that simultaneously bind with one arm to a Tumor Associated Antigen (TAA) on cancer cells and with the other one to CD3 complex on a T-cell to form a TCR-independent immune synapse and circumvent Human Leucocyte Antigen restriction. Among them, the tribodies, such as Tb535H, a bi-specific molecule, made up of a Fab and a scFv domain both targeting 5T4 and another scFv targeting CD3, have demonstrated anti-tumor efficacy in preclinical studies.

Methods

Here, we generated five novel tri-specific and multi-functional tribodies, called 53X tribodies, composed of a 5T4 binding Fab arm and a CD3 binding scFv, but differently from the parental Tb535H, they contain an additional scFv derived from an antibody specific for an immune checkpoint, such as PD-1, PD-L1 or LAG-3.

Results

Compared with the parental Tb535H bi-specific T cell engager targeting 5T4, the novel 53X tribodies retained similar binding properties of Tb535H tribody, but showed enhanced anti-tumor potency due to the incorporation of the checkpoint inhibitory moiety. In particular, one of them, called 53L10, a tri-specific T cell engager targeting 5T4, CD3 and PD-L1, showed the most promising anti-tumor efficacy in vitro and led to complete tumor regression in vivo.

Conclusions

The novel tribodies have the potential to become strong and safe therapeutic drugs, allowing to reduce also the cost of production as one single molecule contains three different specificities including the anti-TAA, anti-CD3 and anti-IC binding arms.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13046-022-02474-3.

Targeted Approaches to HER2-Low Breast Cancer: Current Practice and Future Directions

Simple Summary

HER2-low breast cancer (BC) accounts for more than half of breast cancer patients. Anti-HER2 therapy has been ineffective in HER2-low BC, for which palliative chemotherapy is the main treatment modality. The definitive efficacy of T-Dxd in HER2-low BC breaks previous treatment strategies, which will redefine HER2-low and thus reshape anti-HER2 therapy. This review summarizes detection technologies and novel agents for HER2-low BC, and explores their possible role in future clinics, to provide ideas for the diagnosis and treatment of HER2-low BC.

Abstract

HER2-low breast cancer (BC) has a poor prognosis, making the development of more suitable treatment an unmet clinical need. While chemotherapy is the main method of treatment for HER2-low BC, not all patients benefit from it. Antineoplastic therapy without chemotherapy has shown promise in clinical trials and is being explored further. As quantitative detection techniques become more advanced, they assist in better defining the expression level of HER2 and in guiding the development of targeted therapies, which include directly targeting HER2 receptors on the cell surface, targeting HER2-related intracellular signaling pathways and targeting the immune microenvironment. A new anti-HER2 antibody-drug conjugate called T-DM1 has been successfully tested and found to be highly effective in clinical trials. With this progress, it could eventually be transformed from a disease without a defined therapeutic target into a disease with a defined therapeutic molecular target. Furthermore, efforts are being made to compare the sequencing and combination of chemotherapy, endocrine therapy, and HER2-targeted therapy to improve prognosis to customize the subtype of HER2 low expression precision treatment regimens. In this review, we summarize the current and upcoming treatment strategies, to achieve accurate management of HER2-low BC.

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.

An overview on display systems (phage, bacterial, and yeast display) for production of anticancer antibodies; advantages and disadvantages

Antibodies as ideal therapeutic and diagnostic molecules are among the top-selling drugs providing considerable efficacy in disease treatment, especially in cancer therapy. Limitations of the hybridoma technology as routine antibody generation method in conjunction with numerous developments in molecular biology led to the development of alternative approaches for the streamlined identification of most effective antibodies. In this regard, display selection technologies such as phage display, bacterial display, and yeast display have been widely promoted over the past three decades as ideal alternatives to traditional methods. The display of antibodies on phages is probably the most widespread of these methods, although surface display on bacteria or yeast have been employed successfully, as well. These methods using various sizes of combinatorial antibody libraries and different selection strategies possessing benefits in screening potency, generating, and isolation of high affinity antibodies with low risk of immunogenicity. Knowing the basics of each method assists in the design and retrieval process of antibodies suitable for different diseases, including cancer. In this review, we aim to outline the basics of each library construction and its display method, screening and selection steps. The advantages and disadvantages in comparison to alternative methods, and their applications in antibody engineering will be explained. Finally, we will review approved or non-approved therapeutic antibodies developed by employing these methods, which may serve as therapeutic antibodies in cancer therapy.

Productivity and quality improvement for a symmetric bispecific antibody through the application of intensified perfusion cell culture

Background

Aggregation, fragmentation, and low yield are issues frequently found during the cell culture process of bispecific antibodies (bsAbs), whose inherent complexity likely plays a role in causing these issues.

Methods

In this study, we made a head-to-head comparison between fed-batch cell culture and intensified perfusion cell culture with a symmetric bsAb case.

Results

In comparison with the fed-batch culture, a 6.6-fold improvement in integrated viable cell density and a 10.9-fold improvement in volumetric productivity were achieved with the intensified perfusion mode. In addition, a significant decrease in aggregation and fragmentation was observed with the intensified perfusion cell culture. Furthermore, product homogeneity was improved, which was reflected by the increased percentage of capillary isoelectric focusing main group. The quality improvement with intensified perfusion cell culture can be attributed to the shortened product retention in the bioreactor.

Conclusions

These findings suggest that intensified perfusion cell culture could be a better choice than traditional fed-batch especially for complex molecules like bsAbs. As this is a single case report, future studies on other cases are needed to further confirm the general applicability of this strategy.

Cancer cell-intrinsic resistance to BiTE therapy is mediated by loss of CD58 costimulation and modulation of the extrinsic apoptotic pathway

Background

Bispecific T-cell engager (BiTE) molecules induce redirected lysis of cancer cells by T cells and are an emerging modality for solid tumor immunotherapy. While signs of clinical activity have been demonstrated, efficacy of T-cell engagers (TCEs) in solid tumors settings, molecular determinants of response, and underlying mechanisms of resistance to BiTE therapy require more investigation.

Methods

To uncover cancer cell-intrinsic genetic modifiers of TCE-mediated cytotoxicity, we performed genome-wide CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats) loss-of-function and CRISPRa (CRISPR activation) gain-of-function screens using TCEs against two distinct tumor-associated antigens (TAAs). By using in vitro T-cell cytotoxicity assays and in vivo efficacy studies, we validated the roles of two common pathways identified in our screen, T-cell costimulation pathway and apoptosis pathway, as key modifiers of BiTE activity.

Results

Our genetic screens uncovered TAAs-independent cancer cell-intrinsic genes with functions in autophagy, T-cell costimulation, the apoptosis pathway, chromatin remodeling, and cytokine signaling that altered responsiveness to BiTE-mediated killing. Notably, loss of CD58 (the ligand of the CD2 T-cell costimulatory receptor), a gene frequently altered in cancer, led to decreased TCE-mediated cytotoxicity, T-cell activation and antitumor efficacy in vitro and in vivo. Moreover, the effects of CD58 loss were synergistically compounded by concurrent loss of CD80/CD86 (ligands for the CD28 T-cell costimulatory receptor), whereas joint CD2 and CD28 costimulation additively enhanced TCE-mediated killing, indicating non-redundant costimulatory mechanisms between the two pathways. Additionally, loss of CFLAR (Caspase-8 and FADD Like Apoptosis Regulator), BCL2L1, and BID (BH3 Interacting Domain Death Agonist) induced profound changes in sensitivity to TCEs, indicating that key regulators of apoptosis, which are frequently altered in cancer, impact tumor responsiveness to BiTE therapy.

Conclusions

This study demonstrates that genetic alterations central to carcinogenesis and commonly detected in cancer samples lead to significant modulation of BiTE antitumor activity in vitro and in vivo, findings with relevance for a better understanding of patient responses to BiTE therapy and novel combinations that enhance TCE efficacy.

Antibody-Drug Conjugates Targeting the Human Epidermal Growth Factor Receptor Family in Cancers

Members of the human epidermal growth factor receptor (HER) family, which includes HER1 (also known as EGFR), HER2, HER3 and HER4, have played a central role in regulating cell proliferation, survival, differentiation and migration. The overexpression of the HER family has been recognized as one of the most common cellular dysregulation associated with a wide variety of tumor types. Antibody-drug conjugates (ADCs) represent a new and promising class of anticancer therapeutics that combine the cancer specificity of antibodies with cytotoxicity of chemotherapeutic drugs. Two HER2-directed ADCs, trastuzumane-emtansine (T-DM1) and trastuzumab-deruxtecan (DS-8201a), have been approved for HER2-positive metastatic breast cancer by the U.S. Food and Drug Administration (FDA) in 2013 and 2019, respectively. A third HER2-directed ADC, disitamab vedotin (RC48), has been approved for locally advanced or metastatic gastric or gastroesophageal junction cancer by the NMPA (National Medical Products Administration) of China in 2021. A total of 11 ADCs that target HER family receptors (EGFR, HER2 or HER3) are currently under clinical trials. In this review article, we summarize the three approved ADCs (T-DM1, DS-8201a and RC48), together with the investigational EGFR-directed ADCs (ABT-414, MRG003 and M1231), HER2-directed ADCs (SYD985, ARX-788, A166, MRG002, ALT-P7, GQ1001 and SBT6050) and HER3-directed ADC (U3-1402). Lastly, we discuss the major challenges associated with the development of ADCs, and highlight the possible future directions to tackle these challenges.

Effective Combinations of Immunotherapy and Radiotherapy for Cancer Treatment

Though single tumor immunotherapy and radiotherapy have significantly improved the survival rate of tumor patients, there are certain limitations in overcoming tumor metastasis, recurrence, and reducing side effects. Therefore, it is urgent to explore new tumor treatment methods. The new combination of radiotherapy and immunotherapy shows promise in improving therapeutic efficacy and reducing recurrence by enhancing the ability of the immune system to recognize and eradicate tumor cells, to overcome tumor immune tolerance mechanisms. Nanomaterials, as new drug-delivery-system materials of the 21st century, can maintain the activity of drugs, improve drug targeting, and reduce side effects in tumor immunotherapy. Additionally, nanomaterials, as radiosensitizers, have shown great potential in tumor radiotherapy due to their unique properties, such as light, heat, electromagnetic effects. Here, we review the mechanisms of tumor immunotherapy and radiotherapy and the synergy of radiotherapy with multiple types of immunotherapies, including immune checkpoint inhibitors (ICIs), tumor vaccines, adoptive cell therapy, and cytokine therapy. Finally, we propose the potential for nanomaterials in tumor radiotherapy and immunotherapy.

Recent advances and challenges of bispecific antibodies in solid tumors

Cancer immunotherapy has made remarkable progress in the past decade. Bispecific antibodies (BsAbs) have acquired much attention as the next generation strategy of antibody-target cancer immunotherapy, which overwhelmingly focus on T cell recruitment and dual receptors blockade. So far, BsAb drugs have been proved clinically effective and approved for the treatment of hematologic malignancies, but no BsAb have been approved in solid tumors. Numerous designed BsAb drugs for solid tumors are now undergoing evaluation in clinical trials. In this review, we will introduce the formats of bispecific antibodies, and then update the latest preclinical studies and clinical trials in solid tumors of BsAbs targeting EpCAM, CEA, PMSA, ErbB family, and so on. Finally, we discuss the BsAb-related adverse effects and the alternative strategy for future study.

Targeted Anti-Tumor Immunotherapy Using Tumor Infiltrating Cells

In the tumor microenvironment, T cells, B cells, and many other cells play important and distinct roles in anti-tumor immunotherapy. Although the immune checkpoint blockade and adoptive cell transfer can elicit durable clinical responses, only a few patients benefit from these therapies. Increased understanding of tumor-infiltrating immune cells can provide novel therapies and drugs that induce a highly specific anti-tumor immune response to certain groups of patients. Herein, the recent research progress on tumor-infiltrating B cells and T cells, including CD8+ T cells, CD4+ T cells, and exhausted T cells and their role in anti-tumor immunity, is summarized. Moreover, several anti-tumor therapy approaches are discussed based on different immune cells and their prospects for future applications in cancer treatment.

Immunotherapy for Hepatocellular Carcinoma: Current Status and Future Prospects

Hepatocellular carcinoma (HCC) is the most prevalent primary liver cancer with poor prognosis. Surgery, chemotherapy, and radiofrequency ablation are three conventional therapeutic options that will help only a limited percentage of HCC patients. Cancer immunotherapy has achieved dramatic advances in recent years and provides new opportunities to treat HCC. However, HCC has various etiologies and can evade the immune system through multiple mechanisms. With the rapid development of genetic engineering and synthetic biology, a variety of novel immunotherapies have been employed to treat advanced HCC, including immune checkpoint inhibitors, adoptive cell therapy, engineered cytokines, and therapeutic cancer vaccines. In this review, we summarize the current landscape and research progress of different immunotherapy strategies in the treatment of HCC. The challenges and opportunities of this research field are also discussed.

Novel classes of immunotherapy for breast cancer

Immune-checkpoint inhibitors have profoundly changed the treatment landscape for many tumor types. Despite marked improvements in disease control for highly immunogenic cancers, the clinical impact of checkpoint inhibitors in breast cancers to date is limited. Breast cancer is a heterogeneous disease with different levels of PD-L1 expression and variable tumor microenvironment (TME) composition according to molecular subtype. With emerging evidence of the role of different factors involved in immune evasion, there are promising new immunotherapy targets that will reshape early drug development for metastatic breast cancer. This review examines the available evidence for existing and emerging immuno-oncology (IO) approaches including small molecules targeting different regulators of the cancer-immunity cycle.

Immunotherapy combinations overcome resistance to bispecific T cell engager treatment in T cell-cold solid tumors

Therapeutic approaches are needed to promote T cell-mediated destruction of poorly immunogenic, "cold" tumors typically associated with minimal response to immune checkpoint blockade (ICB) therapy. Bispecific T cell engager (BiTE) molecules induce redirected lysis of cancer cells by polyclonal T cells and have demonstrated promising clinical activity against solid tumors in some patients. However, little is understood about the key factors that govern clinical responses to these therapies. Using an immunocompetent mouse model expressing a humanized CD3ε chain (huCD3e mice) and BiTE molecules directed against mouse CD19, mouse CLDN18.2, or human EPCAM antigens, we investigated the pharmacokinetic and pharmacodynamic parameters and immune correlates associated with BiTE efficacy across multiple syngeneic solid-tumor models. These studies demonstrated that pretreatment tumor-associated T cell density is a critical determinant of response to BiTE therapy, identified CD8⁺ T cells as important targets and mediators of BiTE activity, and revealed an antagonistic role for CD4⁺ T cells in BiTE efficacy. We also identified therapeutic combinations, including ICB and 4-1BB agonism, that synergized with BiTE treatment in poorly T cell-infiltrated, immunotherapy-refractory tumors. In these models, BiTE efficacy was dependent on local expansion of tumor-associated CD8⁺ T cells, rather than their recruitment from circulation. Our findings highlight the relative contributions of baseline T cell infiltration, local T cell proliferation, and peripheral T cell trafficking for BiTE molecule-mediated efficacy, identify combination strategies capable of overcoming resistance to BiTE therapy, and have clinical relevance for the development of BiTE and other T cell engager therapies.

Treatment of solid tumors using bispecific anti-PDL-1/ICOS antibody

PD-L1 and ICOS are immune control points in cancer and their presence in cancer tends to have a poor prognosis. WO2019122882 patent describes a bispecific antibody that targets PDL-1/ICOS with the potential application of cancer treatment. WO2019122882 patent describes a bispecific antibody with antitumor efficacy in CT26 model through of the depletion of T_Reg cells and improved ratio of CD8⁺ T cells: T_Reg in tumor microenvironment. The anti-PDL-1/ICOS antibody is new; however, only preclinical assays are shown using colon carcinoma model. So far, there are no reports of clinical trials to evaluate the safety, toxicity and efficacy, but it will be of great interest to analyze in the future if this antibody surpasses the action of the combinatorial therapy in cancer.