Abstract B120: Designing potent antibody‐drug conjugates: The impact of lysosomal processing efficiency and conjugate linker selection on anticancer activity

Antibody–drug conjugates (ADCs) are heterogeneous biotherapeutics and differ vastly in their physicochemical properties depending on their design. The number of small drug molecules covalently attached to each antibody molecule is commonly referred to as the drug-to-antibody ratio (DAR). Established analytical protocols for mass spectrometry (MS)-investigation of antibodies and ADCs often require sample treatment such as desalting or interchain disulfide bond reduction prior to analysis. Herein, the impact of the desalting and reduction steps—as well as the sample concentration and elapsed time between synthesis and analysis of DAR-values (as acquired by reversed phase liquid chromatography MS (RPLC–MS))—was investigated. It was found that the apparent DAR-values could fluctuate by up to 0.6 DAR units due to changes in the sample preparation workflow. For methods involving disulfide reduction by means of dithiothreitol (DTT), an acidic quench is recommended in order to increase DAR reliability. Furthermore, the addition of a desalting step was shown to benefit the ionization efficiencies in RPLC–MS. Finally, in the case of delayed analyses, samples can be stored at four degrees Celsius for up to one week but are better stored at −20 °C for longer periods of time. In conclusion, the results demonstrate that commonly used sample preparation procedures and storage conditions themselves may impact MS-derived DAR-values, which should be taken into account when evaluating analytical procedures.

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Advances and Limitations of Antibody Drug Conjugates for Cancer

Biomedicines ◽

10.3390/biomedicines9080872 ◽

2021 ◽

Vol 9 (8) ◽

pp. 872

Author(s):

Candice Maria Mckertish ◽

Veysel Kayser

Keyword(s):

Therapeutic Index ◽

Narrow Therapeutic Index ◽

Antibody Drug Conjugates ◽

Drug Conjugates ◽

The Stability ◽

Drug Antibody Ratio ◽

Chemotherapy Agents ◽

The Impact ◽

Antibody Ratio ◽

Antibody Drug

The popularity of antibody drug conjugates (ADCs) has increased in recent years, mainly due to their unrivalled efficacy and specificity over chemotherapy agents. The success of the ADC is partly based on the stability and successful cleavage of selective linkers for the delivery of the payload. The current research focuses on overcoming intrinsic shortcomings that impact the successful development of ADCs. This review summarizes marketed and recently approved ADCs, compares the features of various linker designs and payloads commonly used for ADC conjugation, and outlines cancer specific ADCs that are currently in late-stage clinical trials for the treatment of cancer. In addition, it addresses the issues surrounding drug resistance and strategies to overcome resistance, the impact of a narrow therapeutic index on treatment outcomes, the impact of drug–antibody ratio (DAR) and hydrophobicity on ADC clearance and protein aggregation.

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Antibody-Drug Conjugates: Patient and Treatment Selection

American Society of Clinical Oncology Educational Book ◽

10.1200/edbk_280775 ◽

2020 ◽

pp. 105-114

Author(s):

Shalini Makawita ◽

Funda Meric-Bernstam

Keyword(s):

Patient Selection ◽

Therapeutic Efficacy ◽

Antigen Expression ◽

Therapeutic Modality ◽

Intratumor Heterogeneity ◽

Target Antigen ◽

Antibody Drug Conjugates ◽

Drug Conjugates ◽

The Impact ◽

Antibody Drug

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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The impact of trisulfide modification of antibodies on the properties of antibody-drug conjugates manufactured using thiol chemistry

mAbs ◽

10.1080/19420862.2017.1285478 ◽

2017 ◽

Vol 9 (3) ◽

pp. 490-497 ◽

Cited By ~ 6

Author(s):

Renpeng Liu ◽

Xuan Chen ◽

Junia Dushime ◽

Megan Bogalhas ◽

Alexandru C. Lazar ◽

...

Keyword(s):

Antibody Drug Conjugates ◽

Drug Conjugates ◽

The Impact ◽

Antibody Drug

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Protease-Cleavable Linkers Modulate the Anticancer Activity of Noninternalizing Antibody–Drug Conjugates

Bioconjugate Chemistry ◽

10.1021/acs.bioconjchem.7b00304 ◽

2017 ◽

Vol 28 (7) ◽

pp. 1826-1833 ◽

Cited By ~ 34

Author(s):

Alberto Dal Corso ◽

Samuele Cazzamalli ◽

Rémy Gébleux ◽

Martin Mattarella ◽

Dario Neri

Keyword(s):

Anticancer Activity ◽

Antibody Drug Conjugates ◽

Drug Conjugates ◽

Antibody Drug

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Immunoconjugates for cancer targeting: a review of antibody-drug conjugates and antibody-functionalized nanoparticles

Current Medicinal Chemistry ◽

10.2174/0929867327666200525161359 ◽

2020 ◽

Vol 27 ◽

Cited By ~ 2

Author(s):

Raquel Petrilli ◽

Daniel Pascoalino Pinheiro ◽

Fátima de Cássia Evangelista de Oliveira ◽

Gabriela Fávero Galvão ◽

Lana Grasiela Alves Marques ◽

...

Keyword(s):

Monoclonal Antibodies ◽

Targeted Therapy ◽

Molecular Targets ◽

Clinical Development ◽

Cancer Targeting ◽

Functionalized Nanoparticles ◽

Antibody Drug Conjugates ◽

Drug Conjugates ◽

The Impact ◽

Antibody Drug

: Targeted therapy has been recently highlighted due to the reduction of side effects and improvement in overall efficacy and survival to different types of cancers. Considering the approval of many monoclonal antibodies in the last twenty years, cancer treatment can be accomplished by the combination of monoclonal antibodies and small molecule chemotherapeutics. Thus, strategies to combine both drugs in a single administration system are relevant in the clinic. In this context, two strategies are possible and will be further discussed in this review: antibody-drug conjugates (ADCs) and antibody-functionalized nanoparticles. First, it is important to better understand the possible molecular targets for cancer therapy, addressing different antigens that can selectively bind to antibodies. After selecting the best target, ADCs can be prepared by attaching a cytotoxic drug to an antibody able to target a cancer cell antigen. Briefly, an ADC will be formed by a monoclonal antibody (MAb), a cytotoxic molecule (cytotoxin) and a chemical linker. Usually, surface-exposed lysine or the thiol group of cysteine residues are used as anchor sites for linker-drug molecules. Another strategy that should be considered are antibody-functionalized nanoparticles. Basically, liposomes, polymeric and inorganic nanoparticles can be attached to specific antibodies for targeted therapy. Different conjugation strategies can be used, but nanoparticles coupling between maleimide and thiolated antibodies or activation with the addition of ethyl-3-(3-dimethyl aminopropyl) carbodiimide (EDC)/ N-hydroxysuccinimide (NHS) (1:5) and further addition of the antibody are some of the most used strategies. Herein, molecular targets and conjugation strategies will be presented and discussed to better understand the in vitro and in vivo applications presented. Also, clinical development of ADCs and antibody-conjugated nanoparticles were addressed in the clinical development section. Finally, due to the innovation related to the targeted therapy, it is convenient to analyze the impact on patenting and technology. Information related to temporal evolution of number of patents, distribution of patent holders and also the number of patents related to cancer types are presented and discussed. Thus, our aim is to provide an overview in the recent developments in immunoconjugates for cancer targeting and highlight the most important aspects for clinical relevance and innovation.

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ASCO-GU 2019: Metastasierte Urothelkarzinome

Onkologische Welt ◽

10.1055/a-0869-6415 ◽

2019 ◽

Vol 10 (03) ◽

pp. 140-141

Author(s):

Alexander Kretzschmar

Keyword(s):

San Francisco ◽

Antibody Drug Conjugates ◽

Drug Conjugates ◽

Chapel Hill ◽

Antibody Drug

Die Therapielandschaft des metastasierten Urothelkarzinoms hat sich seit der Zulassung der ersten Immun-Checkpoint-Inhibitoren verändert. Die neuen Therapien sind deutlich effektiver, allerdings erreichen die Responseraten der neuen Therapien nur bis zu etwa 30 %, beklagte Prof. Matthew Milowsky, Chapel Hill/USA, auf einer Oral Abstract Session auf dem ASCO-GU. In San Francisco gaben erste Vorträge und Poster bereits einen Einblick, wovon diejenigen Patienten profitieren könnten, die auf die etablierten Chemotherapien und die neuen Immuntherapien nicht ansprechen. Manche Onkologen sprechen bereits von der „Post-Checkpoint-Ära”. Als Kandidaten werden vor allem Antikörper-Wirkstoff-Konjugate (antibody-drug conjugates; ADC) gehandelt – und zwar nicht nur zur Therapie des metastasierten Blasenkarzinoms.

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