RECEPTOR-MEDIATED ENDOCYTOSIS MODELING OF ANTIBODY-DRUG CONJUGATES TO THE RELEASED PAYLOAD WITHIN THE INTRACELLULAR SPACE CONSIDERING TARGET ANTIGEN EXPRESSION LEVELS

Antibody-drug conjugates (ADCs) are a promising drug platform designed to enhance the therapeutic index and minimize the toxicity of anticancer agents. ADCs have experienced substantial progress and technological growth over the past decades; however, several challenges to patient selection and treatment remain. Methods to optimally capture all patients who may benefit from a particular ADC are still largely unknown. Although target antigen expression remains a biomarker for patient selection, the impact of intratumor heterogeneity on antigen expression, as well as the dynamic changes in expression with treatment and disease progression, are important considerations in patient selection. Better understanding of these factors, as well as minimum levels of target antigen expression required to achieve therapeutic efficacy, will enable further optimization of selection strategies. Other important considerations include understanding mechanisms of primary and acquired resistance to ADCs. Ongoing efforts in the design of its constituent parts to possess the intrinsic ability to overcome these mechanisms, including use of the “bystander effect” to enhance efficacy in heterogeneous or low target antigen-expressing tumors, as well as modulation of the chemical and immunophenotypic properties of antibodies and linker molecules to improve payload sensitivity and therapeutic efficacy, are under way. These strategies may also lead to improved safety profiles. Similarly, combination strategies using ADCs with other cytotoxic or immunomodulatory agents are also under development. Great strides have been made in ADC technology. With further refinements, this therapeutic modality has the potential to make an important clinical impact on a wider range of tumor types.

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Antibody–Drug Conjugates for the Treatment of Breast Cancer

Cancers ◽

10.3390/cancers13122898 ◽

2021 ◽

Vol 13 (12) ◽

pp. 2898

Author(s):

Chiara Corti ◽

Federica Giugliano ◽

Eleonora Nicolò ◽

Liliana Ascione ◽

Giuseppe Curigliano

Keyword(s):

Breast Cancer ◽

Bystander Effect ◽

Metastatic Breast ◽

Therapeutic Index ◽

Cytotoxic Agents ◽

Target Antigen ◽

Her2 Positive ◽

Antibody Drug Conjugates ◽

Drug Conjugates ◽

Antibody Drug

Metastatic breast cancer (BC) is currently an incurable disease. Besides endocrine therapy and targeted agents, chemotherapy is often used in the treatment of this disease. However, lack of tumor specificity and toxicity associated with dose exposure limit the manageability of cytotoxic agents. Antibody–drug conjugates (ADCs) are a relatively new class of anticancer drugs. By merging the selectivity of monoclonal antibodies with the cytotoxic properties of chemotherapy, they improve the therapeutic index of antineoplastic agents. Three core components characterize ADCs: the antibody, directed to a target antigen; the payload, typically a cytotoxic agent; a linker, connecting the antibody to the payload. The most studied target antigen is HER2 with some agents, such as trastuzumab deruxtecan, showing activity not only in HER2-positive, but also in HER2-low BC patients, possibly due to a bystander effect. This property to provide a cytotoxic impact also against off-target cancer cells may overcome the intratumoral heterogeneity of some target antigens. Other cancer-associated antigens represent a strategy for the development of ADCs against triple-negative BC, as shown by the recent approval of sacituzumab govitecan. In this review, we discuss the current landscape of ADC development for the treatment of BC, as well as the possible limitations of this treatment.

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Antibody-Drug Conjugates Designed to Eradicate Tumors with Homogeneous and Heterogeneous Expression of the Target Antigen

Cancer Research ◽

10.1158/0008-5472.can-05-3973 ◽

2006 ◽

Vol 66 (6) ◽

pp. 3214-3221 ◽

Cited By ~ 251

Author(s):

Yelena V. Kovtun ◽

Charlene A. Audette ◽

Yumei Ye ◽

Hongsheng Xie ◽

Mary F. Ruberti ◽

...

Keyword(s):

Target Antigen ◽

Antibody Drug Conjugates ◽

Drug Conjugates ◽

Heterogeneous Expression ◽

Antibody Drug

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Antibody-Drug Conjugates and Targeted Treatment Strategies for Hepatocellular Carcinoma: A Drug-Delivery Perspective

Molecules ◽

10.3390/molecules25122861 ◽

2020 ◽

Vol 25 (12) ◽

pp. 2861

Author(s):

David Dahlgren ◽

Hans Lennernäs

Keyword(s):

Hepatocellular Carcinoma ◽

Drug Delivery ◽

Cancer Cell ◽

Cancer Biology ◽

Cytotoxic Drug ◽

Target Antigen ◽

Target Cells ◽

Antibody Drug Conjugates ◽

Drug Conjugates ◽

Antibody Drug

Increased understanding of cancer biology, pharmacology and drug delivery has provided a new framework for drug discovery and product development that relies on the unique expression of specific macromolecules (i.e., antigens) on the surface of tumour cells. This has enabled the development of anti-cancer treatments that combine the selectivity of antibodies with the efficacy of highly potent chemotherapeutic small molecules, called antibody-drug conjugates (ADCs). ADCs are composed of a cytotoxic drug covalently linked to an antibody which then selectively binds to a highly expressed antigen on a cancer cell; the conjugate is then internalized by the cell where it releases the potent cytotoxic drug and efficiently kills the tumour cell. There are, however, many challenges in the development of ADCs, mainly around optimizing the therapeutic/safety benefits. These challenges are discussed in this review; they include issues with the plasma stability and half-life of the ADC, its transport from blood into and distribution throughout the tumour compartment, cancer cell antigen expression and the ADC binding affinity to the target antigen, the cell internalization process, cleaving of the cytotoxic drug from the ADC, and the cytotoxic effect of the drug on the target cells. Finally, we present a summary of some of the experimental ADC strategies used in the treatment of hepatocellular carcinoma, from the recent literature.

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Antibody Drug Conjugates in Glioblastoma – Is There a Future for Them?

Frontiers in Oncology ◽

10.3389/fonc.2021.718590 ◽

2021 ◽

Vol 11 ◽

Author(s):

Sagun Parakh ◽

Joseph Nicolazzo ◽

Andrew M Scott ◽

Hui Kong Gan

Keyword(s):

Therapeutic Potential ◽

Antigen Expression ◽

Tumour Volume ◽

Factors Affecting ◽

Antibody Drug Conjugates ◽

Drug Conjugates ◽

Limited Success ◽

Immunosuppressive Tumor Microenvironment ◽

Reduced Toxicity ◽

Antibody Drug

Glioblastoma (GBM) is an aggressive and fatal malignancy that despite decades of trials has limited therapeutic options. Antibody drug conjugates (ADCs) are composed of a monoclonal antibody which specifically recognizes a cellular surface antigen linked to a cytotoxic payload. ADCs have demonstrated superior efficacy and/or reduced toxicity in a range of haematological and solid tumors resulting in nine ADCs receiving regulatory approval. ADCs have also been explored in patients with brain tumours but with limited success to date. While earlier generations ADCs in glioma patients have had limited success and high toxicity, newer and improved ADCs characterised by low immunogenicity and more effective payloads have shown promise in a range of tumour types. These newer ADCs have also been tested in glioma patients, however, with mixed results. Factors affecting the effectiveness of ADCs to target the CNS include the blood brain barrier which acts as a physical and biochemical barrier, the pro-cancerogenic and immunosuppressive tumor microenvironment and tumour characteristics like tumour volume and antigen expression. In this paper we review the data regarding the ongoing the development of ADCs in glioma patients as well as potential strategies to overcome these barriers to maximise their therapeutic potential.

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Eradicating mesothelin-positive human gastric and pancreatic tumors in xenograft models with optimized anti-mesothelin antibody–drug conjugates from synthetic antibody libraries

Scientific Reports ◽

10.1038/s41598-021-94902-1 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Hung-Ju Hsu ◽

Chao-Ping Tung ◽

Chung-Ming Yu ◽

Chi-Yung Chen ◽

Hong-Sen Chen ◽

...

Keyword(s):

Cancer Therapeutics ◽

Tumor Xenograft ◽

Pancreatic Tumors ◽

Target Antigen ◽

Antibody Drug Conjugates ◽

Synthetic Antibody ◽

Drug Conjugates ◽

Xenograft Models ◽

Antibody Drug

AbstractMesothelin (MSLN) is an attractive candidate of targeted therapy for several cancers, and hence there are increasing needs to develop MSLN-targeting strategies for cancer therapeutics. Antibody–drug conjugates (ADCs) targeting MSLN have been demonstrated to be a viable strategy in treating MSLN-positive cancers. However, developing antibodies as targeting modules in ADCs for toxic payload delivery to the tumor site but not to normal tissues is not a straightforward task with many potential hurdles. In this work, we established a high throughput engineering platform to develop and optimize anti-MSLN ADCs by characterizing more than 300 scFv CDR-variants and more than 50 IgG CDR-variants of a parent anti-MSLN antibody as candidates for ADCs. The results indicate that only a small portion of the complementarity determining region (CDR) residues are indispensable in the MSLN-specific targeting. Also, the enhancement of the hydrophilicity of the rest of the CDR residues could drastically increase the overall solubility of the optimized anti-MSLN antibodies, and thus substantially improve the efficacies of the ADCs in treating human gastric and pancreatic tumor xenograft models in mice. We demonstrated that the in vivo treatments with the optimized ADCs resulted in almost complete eradication of the xenograft tumors at the treatment endpoints, without detectable off-target toxicity because of the ADCs’ high specificity targeting the cell surface tumor-associated MSLN. The technological platform can be applied to optimize the antibody sequences for more effective targeting modules of ADCs, even when the candidate antibodies are not necessarily feasible for the ADC development due to the antibodies’ inferior solubility or affinity/specificity to the target antigen.

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Monoclonal Antibodies, Bispecific Antibodies and Antibody-Drug Conjugates in Oncohematology

Recent Patents on Anti-Cancer Drug Discovery ◽

10.2174/1574892815666200925120717 ◽

2020 ◽

Vol 15 (4) ◽

pp. 272-292

Author(s):

Romeo G. Mihăilă

Keyword(s):

Monoclonal Antibodies ◽

Target Cell ◽

Residual Disease ◽

Standard Of Care ◽

Bispecific Antibodies ◽

Target Antigen ◽

Target Cells ◽

Antibody Drug Conjugates ◽

Drug Conjugates ◽

Antibody Drug

Background: The therapeutic outcomes and the prognosis of patients with various hematologic malignancies are not always ideal with the current standard of care. Objective: The aim of this study is to analyze the results of the use of monoclonal antibodies, bispecific antibodies and antibody-drug conjugates for the therapy of malignant hemopathies. Methods: A mini-review was achieved using the articles published in Web of Science and PubMed between January 2017 and January 2020 and the new patents were made in this field. Results: Naked monoclonal antibodies have improved the therapeutic results obtained with standard of care, but they also have side effects and the use of some of them can lead to the loss of the target antigen through trogocytosis, which explains the resistance that occurs during therapy. The results obtained with naked monoclonal antibodies have been improved by a better monoclonal antibody preparation, the use of bispecific antibodies (against two antigens on the target cell surface or by binding both surface antigen on target cells and T-cell receptor complex, followed by cytotoxic T-lymphocytes activation and subsequent cytolysis of the target cell), the use of monoclonal or bispecific constructs in frontline regimens, combining immunotherapy with chemotherapy, including through the use of antibody-drug conjugates (which provides a targeted release of a chemotherapeutic agent). Conclusion: Immunotherapy and immuno-chemotherapy have improved the outcome of the patients with malignant hemopathies through a targeted, personalized therapy, with reduced systemic toxicity, which in some cases can even induce deep complete remissions, including minimal residual disease negativity.

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Bispecific Antibodies and Antibody–Drug Conjugates for Cancer Therapy: Technological Considerations

Biomolecules ◽

10.3390/biom10030360 ◽

2020 ◽

Vol 10 (3) ◽

pp. 360 ◽

Cited By ~ 10

Author(s):

Hyunbo Shim

Keyword(s):

Therapeutic Antibody ◽

Bispecific Antibodies ◽

Target Antigen ◽

Antibody Drug Conjugates ◽

Medical Needs ◽

Drug Conjugates ◽

Recent Developments ◽

Technological Developments ◽

Approved Drugs ◽

Antibody Drug

The ability of monoclonal antibodies to specifically bind a target antigen and neutralize or stimulate its activity is the basis for the rapid growth and development of the therapeutic antibody field. In recent years, traditional immunoglobulin antibodies have been further engineered for better efficacy and safety, and technological developments in the field enabled the design and production of engineered antibodies capable of mediating therapeutic functions hitherto unattainable by conventional antibody formats. Representative of this newer generation of therapeutic antibody formats are bispecific antibodies and antibody–drug conjugates, each with several approved drugs and dozens more in the clinical development phase. In this review, the technological principles and challenges of bispecific antibodies and antibody–drug conjugates are discussed, with emphasis on clinically validated formats but also including recent developments in the fields, many of which are expected to significantly augment the current therapeutic arsenal against cancer and other diseases with unmet medical needs.

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