Antibody Drug Conjugates For Cancer Therapy Research Articles

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.

Antibody-drug conjugates in cancer therapy: innovations, challenges, and future directions.

The emergence of antibody-drug conjugates (ADCs) as a potential therapeutic avenue in cancer treatment has garnered significant attention. By combining the selective specificity of monoclonal antibodies with the cytotoxicity of drug molecules, ADCs aim to increase the therapeutic index, selectively targeting cancer cells while minimizing systemic toxicity. Various ADCs have been licensed for clinical usage, with ongoing research paving the way for additional options. However, the manufacture of ADCs faces several challenges. These include identifying suitable target antigens, enhancing antibodies, linkers, and payloads, and managing resistance mechanisms and side effects. This review focuses on the strategies to overcome these hurdles, such as site-specific conjugation techniques, novel antibody formats, and combination therapy. Our focus lies on current advancements in antibody engineering, linker technology, and cytotoxic payloads while addressing the challenges associated with ADC development. Furthermore, we explore the future potential of personalized medicine, leveraging individual patients' molecular profiles, to propel ADC treatments forward. As our understanding of the molecular mechanisms driving cancer progression continues to expand, we anticipate the development of new ADCs that offer more effective and personalized therapeutic options for cancer patients.

Trends in the Development of Antibody-Drug Conjugates for Cancer Therapy.

In cancer treatment, the first-generation, cytotoxic drugs, though effective against cancer cells, also harmed healthy ones. The second-generation targeted cancer cells precisely to inhibit their growth. Enter the third-generation, consisting of immuno-oncology drugs, designed to combat drug resistance and bolster the immune system's defenses. These advanced therapies operate by obstructing the uncontrolled growth and spread of cancer cells through the body, ultimately eliminating them effectively. Within the arsenal of cancer treatment, monoclonal antibodies offer several advantages, including inducing cancer cell apoptosis, precise targeting, prolonged presence in the body, and minimal side effects. A recent development in cancer therapy is Antibody-Drug Conjugates (ADCs), initially developed in the mid-20th century. The second generation of ADCs addressed this issue through innovative antibody modification techniques, such as DAR regulation, amino acid substitutions, incorporation of non-natural amino acids, and enzymatic drug attachment. Currently, a third generation of ADCs is in development. This study presents an overview of 12 available ADCs, reviews 71 recent research papers, and analyzes 128 clinical trial reports. The overarching objective is to gain insights into the prevailing trends in ADC research and development, with a particular focus on emerging frontiers like potential targets, linkers, and drug payloads within the realm of cancer treatment.

Disitamab vedotin: a novel antibody-drug conjugates for cancer therapy

Human epidermal growth factor receptor 2 (HER2) regulates cell mitosis, proliferation, and apoptosis. Trastuzumab is a HER2-targeted monoclonal antibody (mAB), which can prolong the overall survival rate of patients with HER2 overexpression in later periods of gastric cancer and breast cancer. Although anti-HER2 monoclonal antibody has a curative effect, adjuvant chemotherapy is still necessary to upgrade the curative effect maximumly. Antibody-drug conjugate (ADC) is a kind of therapeutic drug that contains antigen-specific antibody and cytotoxic payload, which can improve the survival time of tumor patients. To date, there are several HER2-ADC products on the market, for which two anti-HER2 ADC (trastuzumab emtansine and trastuzumab deruxtecan) have been authorized by the FDA for distinct types of HER2-positive carcinoma in the breast. Disitamab vedotin (RC48) is a newly developed ADC drug targeting HER2 that is comprised of hertuzumab coupling monomethyl auristatin E (MMAE) via a cleavable linker. This paper aims to offer a general insight and summary of the mechanism of action and the currently completed and ongoing clinical studies of RC-48 in HER-2 positive solid tumors.

An Insight into FDA Approved Antibody-Drug Conjugates for Cancer Therapy.

The large number of emerging antibody-drug conjugates (ADCs) for cancer therapy has resulted in a significant market ‘boom’, garnering worldwide attention. Despite ADCs presenting huge challenges to researchers, particularly regarding the identification of a suitable combination of antibody, linker, and payload, as of September 2021, 11 ADCs have been granted FDA approval, with eight of these approved since 2017 alone. Optimism for this therapeutic approach is clear, despite the COVID-19 pandemic, 2020 was a landmark year for deals and partnerships in the ADC arena, suggesting that there remains significant interest from Big Pharma. Herein we review the enthusiasm for ADCs by focusing on the features of those approved by the FDA, and offer some thoughts as to where the field is headed.

Antibody-Drug Conjugates for Cancer Therapy - Prospects and Challenges

Antibody-Drug Conjugates for Cancer Therapy - Prospects and Challenges

Optimizing the anti-tumor efficacy of protein-drug conjugates by engineering the molecular size and half-life

Despite some approvals of antibody-drug conjugates for cancer therapy, their clinical success rate is unsatisfactory because of very small therapeutic windows, influenced by on-target and off-target toxicities of conjugate and liberated toxin. Additional formats with systematically investigated molecular parameters must therefore be explored to increase their therapeutic window. Here we focused on the effective molecular weight. To generate conjugates with exactly defined drug loads and tunable pharmacokinetics, we used Designed Ankyrin Repeat Proteins (DARPins), fused to unstructured polypeptides of different lengths, to produce proteins with any desired half-life, to identify those with the best efficacy. We generated an EpCAM-targeting DARPin-MMAF conjugate, fused to PAS or XTEN of different lengths, and a matched series of controls of a non-binding DARPin to account for the enhanced permeability and retention (EPR) effect, covering half-lives of minutes to 20.6 h in mice. All conjugates were produced at high purity, and demonstrated high specificity and cytotoxicity in human tumor cell cultures, with IC50 values in the low nM range, independent of the polypeptide type and length. Due to their more facile purification, the PASylated conjugates were tested in nude mice bearing HT29 tumor xenografts. Independent of their size, all PASylated conjugates were very well tolerated after repeated systemic administration of 300 nmol/kg. We found that the conjugates with intermediate size and half-life showed the strongest anti-tumor effects, and deduced that this effect is a compromise of serum half-life and diffusion within the tumor, as on-rates and affinities are essentially identical, with extravasation playing only a very minor role.

Tubulin Maytansine Site Binding Ligands and their Applications as MTAs and ADCs for Cancer Therapy.

Microtubule Targeting Agents (MTAs) represent the most successful anticancer drugs for cancer chemotherapy. Through interfering with the tubulin polymerization and depolymerization dynamics, MTAs influence intracellular transport and cell signal pathways, inhibit cell mitosis and cell proliferation, and induce cell apoptosis and death. The tubulin maytansine site binding agents are natural or nature-derived products that represent one type of the MTAs that inhibit tubulin polymerization and exhibit potent antitumor activity both in vitro and in vivo. They are used as Antibody-Drug Conjugates (ADCs) in cancer chemotherapy. Using SciFinder® as a tool, the publications about maytansine, its derivatives, maytansine binding site, maytansine site binding agents and their applications as MTAs for cancer therapy were surveyed with an exclusion on those published as patents. The latest progresses in clinical trials were obtained from the clinical trial web. This article presents an introduction about MTAs, maytansine, maytansine binding site and its ligands, the applications of these ligands as MTAs and ADCs in cancer therapy. The maytansine site binding agents are powerful MTAs for cancer chemotherapy. The maytansine site ligands-based ADCs are used in clinic or under clinical trials as cancer targeted therapy to improve their selectivity and to reduce their side effects. Further improvements in the delivery efficiency of the ADCs will benefit the patients in cancer targeted therapy.

DNA damaging agent-based antibody-drug conjugates for cancer therapy.

Currently, four antibody-drug conjugates (ADCs) are approved by the Food and Drug Administration or the European Medicine Agency to treat cancer patients. More than 60 ADCs are in clinical development for cancer therapy. More than 60% of ADCs in clinical trials employ microtubule inhibitors as their payloads. A better understanding of payloads other than microtubule inhibitors, especially DNA-damaging agents, is important for further development of ADCs. In this review, we highlight an emerging trend of using DNA-damaging agents as payloads for ADCs. This review summarizes recent advances in our understanding gained from ongoing clinical studies; it will help to define the utility of DNA-damaging payloads for ADCs as cancer therapeutics. Future directions of the development of ADCs are also discussed, focusing on targeting drug resistance and combination treatment with immunotherapy.

Antibody-Drug Conjugates for Cancer Therapy: Chemistry to Clinical Implications.

Chemotherapy is one of the major therapeutic options for cancer treatment. Chemotherapy is often associated with a low therapeutic window due to its poor specificity towards tumor cells/tissues. Antibody-drug conjugate (ADC) technology may provide a potentially new therapeutic solution for cancer treatment. ADC technology uses an antibody-mediated delivery of cytotoxic drugs to the tumors in a targeted manner, while sparing normal cells. Such a targeted approach can improve the tumor-to-normal tissue selectivity and specificity in chemotherapy. Considering its importance in cancer treatment, we aim to review recent efforts for the design and development of ADCs. ADCs are mainly composed of an antibody, a cytotoxic payload, and a linker, which can offer selectivity against tumors, anti-cancer activity, and stability in systemic circulation. Therefore, we have reviewed recent updates and principal considerations behind ADC designs, which are not only based on the identification of target antigen, cytotoxic drug, and linker, but also on the drug-linker chemistry and conjugation site at the antibody. Our review focuses on site-specific conjugation methods for producing homogenous ADCs with constant drug-antibody ratio (DAR) in order to tackle several drawbacks that exists in conventional conjugation methods.

A non-internalizing antibody-drug conjugate based on an anthracycline payload displays potent therapeutic activity in vivo

Antibody-drug conjugates are generally believed to crucially rely on internalization into cancer cells for therapeutic activity. Here, we show that a non-internalizing antibody-drug conjugate, based on the F16 antibody specific to the alternatively spliced A1 domain of tenascin-C, mediates a potent therapeutic activity when equipped with the anthracycline PNU159682. The peptide linker, connecting the F16 antibody in IgG format at a specific cysteine residue to the drug, was stable in serum but could be efficiently cleaved in the subendothelial extracellular matrix by proteases released by the dying tumor cells. The results indicate that there may be a broader potential applicability of non-internalizing antibody-drug conjugates for cancer therapy than what had previously been assumed.

Antibody Drug Conjugates (ADCs): Changing the Treatment Landscape of Lymphoma

While strides advancing cancer treatment have made it possible to cure some malignancies, the effort to strike an intricate balance between attaining higher efficacy and lower toxicity has been difficult to accomplish, especially with conventional chemotherapy agents. Introduction of antibody drug conjugates (ADCs) has brought us a step closer to this goal and made it possible to target the cancer cells and to minimize effects on normal tissue. Continued efforts have led to approval of two ADCs for cancer therapy, while many others are in various stages of clinical development. The design of ADCs allows them to be internalized into the cancer cells where the drug payload is released and leads to cell death. The key is to identify targets that are exclusively expressed on malignant cells with minimal or no expression on normal cells, which allows for selective killing of tumor cells. Development and approval of more potent ADCs could change the landscape of cancer therapy and possibly eliminate traditional chemotherapy agents from treatment algorithms. In this review, we discuss the ADCs that are being investigated in early and late stage clinical trials for the treatment of B cell non-Hodgkin lymphoma (NHL).

Antibody-Drug Conjugates for Cancer Therapy.

Antibody–drug conjugates (ADCs) take advantage of the specificity of a monoclonal antibody to deliver a linked cytotoxic agent directly into a tumour cell. The development of these compounds provides exciting opportunities for improvements in patient care. Here, we review the key issues impacting on the clinical success of ADCs in cancer therapy. Like many other developing therapeutic classes, there remain challenges in the design and optimisation of these compounds. As the clinical applications for ADCs continue to expand, key strategies to improve patient outcomes include better patient selection for treatment and the identification of mechanisms of therapy resistance.

Structural Insights into the Pharmacophore of Vinca Domain Inhibitors of Microtubules.

Antibody-drug conjugates (ADCs) have achieved great success in cancer therapy in recent years. Some peptidyl microtubule inhibitors consisting of natural and unnatural amino acids, such as monomethyl auristatin E (MMAE) and F (MMAF), are extremely cytotoxic and have been used as a payload in ADCs. However, their precise molecular interaction with tubulin and microtubules remains unclear. We determined the crystal structures of tubulin in complex with three ultra-potent peptidyl microtubule inhibitors [MMAE, taltobulin (HTI- 286), and tubulysin M] at 2.5 Å. Our data showed that the three peptides bound to the vinca domain and shared a common and key pharmacophore containing two consecutive hydrophobic groups (Val, Ile-like side chain). These groups protruded in opposite directions into hydrophobic pockets on the tubulin β and α subunits. Nitrogen and oxygen atoms from the same backbone formed hydrogen bonds with Asn329 from the α subunit and Asp179 from the β subunit in a direction normal to the surface formed by the aforementioned hydrophobic groups. In addition, our crystal structure data indicated that tubulysin M bound to the β subunit alone, providing a structural explanation for its higher affinity. We also compared the conformations of two representative structurally different vinca domain compounds, ustiloxin D and vinblastine, with those of the aforementioned peptidyl ligands, and found that they shared a similar pharmacophore. Our findings lay a foundation for the rational design of novel vinca domain ligands and may facilitate the development of microtubule inhibitors with high specificity, affinity, and efficiency as payloads for ADCs in cancer therapy.

Intracellular Delivery System for Antibody–Peptide Drug Conjugates

Antibodies armed with biologic drugs could greatly expand the therapeutic potential of antibody-drug conjugates for cancer therapy, broadening their application to disease targets currently limited by intracellular delivery barriers. Additional selectivity and new therapeutic approaches could be realized with intracellular protein drugs that more specifically target dysregulated pathways in hematologic cancers and other malignancies. A multifunctional polymeric delivery system for enhanced cytosolic delivery of protein drugs has been developed that incorporates endosomal-releasing activity, antibody targeting, and a biocompatible long-chain ethylene glycol component for optimized safety, pharmacokinetics, and tumor biodistribution. The pH-responsive polymeric micelle carrier, with an internalizing anti-CD22 monoclonal targeting antibody, effectively delivered a proapoptotic Bcl-2 interacting mediator (BIM) peptide drug that suppressed tumor growth for the duration of treatment and prolonged survival in a xenograft mouse model of human B-cell lymphoma. Antitumor drug activity was correlated with a mechanistic induction of the Bcl-2 pathway biomarker cleaved caspase-3 and a marked decrease in the Ki-67 proliferation biomarker. Broadening the intracellular target space by more effective delivery of protein/peptide drugs could expand the repertoire of antibody-drug conjugates to currently undruggable disease-specific targets and permit tailored drug strategies to stratified subpopulations and personalized medicines.

Abstract 4321: Development of pyrrolobenzodiazepine-based antibody-drug conjugates for cancer.

Abstract Pyrrolobenzodiazepine (PBD) dimers are highly cytotoxic minor groove binding DNA crosslinking agents derived from the anthramycin class of natural products. In our efforts to develop highly effective and well-tolerated treatment options for cancer patients, we have investigated several antibody-drug conjugates (ADCs) based on a PBD dimer. The fully synthetic PBD-linker, comprised of a protease-cleavable val-ala sequence and a reactive maleimide group, was conjugated via engineered cysteine residues to humanized monoclonal antibodies specific for their binding to the well-characterized cancer antigen targets, CD33 and CD70. The resulting ADCs were well-defined, monomeric and showed pronounced in vitro and in vivo activity against both hematologic and solid tumor cancer models. These included models of acute myelogenous leukemia, Hodgkin lymphoma, non-Hodgkin lymphoma and renal cell carcinoma. The ADCs were immunologically specific, and showed potent activity in MDR-positive models, including models resistant to other ADCs. These results underscore the importance of the drug component in developing highly efficacious ADCs for cancer therapy. Citation Format: Scott C. Jeffrey, Patrick J. Burke, May K. Sutherland, David W. Meyer, Robert P. Lyon, Julie A. McEarchern, Che-Leung Law, Peter D. Senter. Development of pyrrolobenzodiazepine-based antibody-drug conjugates for cancer. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 4321. doi:10.1158/1538-7445.AM2013-4321

Antibody-Drug Conjugates in Cancer Therapy

An antibody-drug conjugate (ADC) provides the possibility of selectively ablating cancer cells by combining the specificity of a monoclonal antibody (mAb) for a target antigen with the delivery of a highly potent cytotoxic agent. ADC target antigens are typically highly expressed on the surface of cancer cells compared to normal cells. The tumor target, the cytotoxic agent, and the manner in which the agent is attached to the antibody are key determinants of clinical activity and tolerability. Recently, several clinical trials have demonstrated that ADCs achieve higher clinical response rates than unconjugated mAbs targeting the same cell surface antigen. Brentuximab vedotin represents one such ADC that has recently been approved for the treatment of relapsed Hodgkin and systemic anaplastic large cell lymphomas--both characterized by high expression of the target antigen, CD30, on the surface of malignant cells. This review summarizes key characteristics of current, clinically active ADCs and highlights recent clinical data illustrating the benefit of antibody-targeted delivery of cytotoxic agents to cancer cells.

Antibody-Drug Conjugates for Cancer Therapy

The antibody-drug conjugate (ADC) concept is to use an antibody to deliver a cytotoxic drug selectively to a target such as a tumor-associated antigen. Such conjugates represent a broadly applicable approach to enhance the antitumor activity of antibodies and improve the tumor-to-normal tissue selectivity of chemotherapy. Critical parameters for ADC development include target antigen selection, conjugate internalization by tumor cells, drug potency and stability of the linker between drug and antibody. Other important considerations include the conjugation methods, drug-to-antibody ratio, and the effects of drug conjugation on antibody properties. Highly potent drugs with more stable linkers have been attached to a new generation of antibodies to create conjugates with pronounced antitumor activities in preclinical studies and encouraging results in early stage clinical trials. This review details these advances, discusses some of the remaining challenges, and overviews ADCs currently in clinical trials for cancer therapy.

Antibody-Drug Conjugates for Cancer Therapy

Antibody-Drug Conjugates for Cancer Therapy

Antibody-Drug Conjugates for Cancer Therapy: Promises and Problems

Antibody-Drug Conjugates for Cancer Therapy: Promises and Problems