Antibody-drug conjugates (ADCs) are a novel therapeutic that combines highly targeted monoclonal antibodies with cytotoxic small molecule drugs, and have become a rising trend due to their precise and powerful mode of action. ADCs have the characteristics of both small molecule and macromolecular therapeutics, and are often present in vivo as complex and dynamically changing mixtures resulting from biotransformation and DAR changes. These bring unique challenges to ADC DMPK and bioanalytical research. This blog will summarize the marketed ADC drugs and introduce the comprehensive DMPK and bioanalytical strategies for ADC drugs.
Summary of 15 approved ADCs by 2024
As of July 2024, 15 ADC drugs have been approved by regulatory authorities worldwide, covering multiple indications such as hematologic tumors and solid tumors.
ADC drug | Trade name | Maker | Disease indication | Payload/payload class | Payload action | Target | mAb | Linker | DAR | Approval year |
Mirvetuximab soravtansine | ELAHERE | ImmunoGen | Ovarian Cancer | Maytansinoid DM4 | Microtubule inhibition | FRα | IgG1 | Enzyme cleavable | 3.5 | FDA 2022 |
Tisotumab vedotin-tftv | Tivdak | Seagen Inc | Cervical cancer | MMAE /auristatin | Microtubule inhibition | Tissue factor | IgG1 | Enzyme cleavable | 4 | FDA 2021 |
Disitamab vedotin | Aidixi | RemeGen | Gastric carcinoma | MMAE /auristatin | Microtubule inhibition | HER2 | IgG1 | Enzyme cleavable | 4 | NMPA 2021 |
Cetuximab sarotalocan | Akalux | Rakuten Medical | Head and neck cancer | Photosensitizing dye | Damage cell membrane | EGFR | Chimeric IgG1 | Non-cleavable | 1.3-3.8 | PMDA 2021 |
Loncastuximab tesirine-lpyl | Zynlonta | ADC Therapeutics | Large B-cell lymphoma | SG3199/PBD dimer | DNA damage | CD19 | IgG1 | Enzyme cleavable | SG3199/PBD dimer | FDA 2021 |
Belantamab mafodotin-blmf | Blenrep | GlaxoSmithKline (GSK) | Multiple myeloma | MMAF /auristatin | Microtubule inhibition | BCMA | IgG1 | Non-cleavable | 4 | FDA 2020, withdrawn on 22 Nov. 2022 |
Sacituzumab govitecan | Trodelvy | Immunomedics | Triple-negative breast cancer | SN-38 /camptothecin | TOP1 inhibition | TROP2 | IgG1 | Acid cleavable | 7.6 | FDA 2020 |
Trastuzumab deruxtecan | Enhertu | AstraZeneca/Daiichi Sankyo | HER2-positive breast cancer | DXd /camptothecin | TOP1 inhibition | HER2 | IgG1 | Enzyme cleavable | 8 | FDA 2019 |
Enfortumab vedotin | Padcev | Astellas/Seagen Genetics | Urothelial cancer | MMAE /auristatin | Microtubule inhibition | Nectin4 | IgG1 | Enzyme cleavable | 3.8 | FDA 2019 |
Polatuzumab vedotin-piiq | Polivy | Genentech, Roche | Diffuse large B-cell lymphoma | MMAE /auristatin | Microtubule inhibition | CD79 | IgG1 | Enzyme cleavable | 3.5 | FDA 2019 |
Moxetumomab pasudotox | Lumoxiti | Astrazeneca | Hairy cell leukemia | PE38 (Pseudotox) | Immunotoxin | CD22 | IgG1 | Cleavable | N/A | FDA 2018 |
Inotuzumab ozogamicin | Besponsa | Pfizer/Wyeth | Lymphoblastic leukemia | Ozogamicin /calicheamicin | DNA damage | CD22 | IgG4 | Acid cleavable | 6 | FDA 2017 |
Trastuzumab emtansine | Kadcyla | Genentech, Roche | HER2-positive metastatic breast cancer | DM1 /maytansinoid | Microtubule inhibition | HER2 | IgG1 | Non-cleavable | 3.5 | FDA 2013 |
Brentuximab vedotin | Adcetris | Seagen Genetics, Millennium/Takeda | Relapsed HL and relapsed sALCL | MMAE /auristatin | Microtubule inhibition | CD30 | IgG1 | Enzyme cleavable | 4 | FDA 2011 |
Gemtuzumab ozogamicin | Mylotarg | Pfizer/Wyeth | Relapsed acute myelogenous leukemia | Ozogamicin /calicheamicin | DNA damage | CD33 | IgG4 | Acid cleavable | 2–3 | FDA 2017; 2000 |
Table 1. Summary of 15 approved ADCs
DMPK research contents of ADCs
ADCs feature a complex structure and diverse dynamic processes in vivo, and their ADME characteristics are highly correlated with their pharmacological efficacy and toxicity. Carrying out the following DMPK studies for ADC drugs is recommended.
Recommended DMPK Studies | Object | Guidance/white paper description |
In-vitro stability | ADC | Before clinical study, need to evaluate the ADC plasma/whole blood stability in human and relevant animal species. |
In-vivo PK | Total antibody/conjugated antibody/payload/major metabolites | In-vivo PK generally monitors total antibodies, conjugated antibodies, and free payloads or major metabolites. |
Met ID and biotransformation | Linker-payload | For new linker-payloads, it is necessary to understand the major metabolites. |
Plasma protein binding | Payload/major metabolites | If the payload or major metabolites is new. |
Drug metabolism phenotyping | Payload/major metabolites | |
Transporters | Payload/major metabolites | |
Enzyme induction/inhibition | Payload/major metabolites | |
In-vivo ADME | Payload/major metabolites |
Table 2. Recommended DMPK studies for ADC drugs
Integrated bioanalytical strategies for ADC drugs
The absorption, distribution, metabolism, and excretion of ADC drugs in various tissues directly affect the efficacy and safety of ADCs, making their bioanalysis more challenging than other drugs. Not only large molecules (total antibodies and conjugated antibodies) but also small molecule components (free and conjugated payloads) need to be taken into consideration. Bioanalysis of total antibodies, conjugated antibodies, free payloads, and related metabolites is essential throughout all stages, including early discovery/screening, preclinical, and clinical development of ADC drugs. A comprehensive bioanalytical approach is required to properly assess the ADME properties of ADC drugs.
Figure 1. Bioanalytical considerations for ADC drugs
By utilizing multiple analytical platforms and employing a combination of small molecule/large molecule and hybrid analysis methods, suitable analysis strategies can be devised to tackle specific challenges in ADC drug development effectively.
Platforms | Applications | Notes |
LBA |
| Bioanalysis of conjugated antibody requires anti-payload antibody |
Low-resolution mass spectrometry (triple quadrupole) |
| Often supported by Met ID (metabolite identification) data |
High-resolution mass spectrometry |
| Plasma/tumor cell/hepatocyte metabolite identification is performed as needed |
Hybrid LBA-LC/(HR)MS |
| Fit for purpose design based on ADC structure; if anti-payload antibody is not available, semi-quantification of ADC |
Quantitative whole-body autoradiography QWBA |
| Pre-isotope labeling of the payload is required |
Table 3. ADC bioanalytical platform and applications
Figure 2. DMPK integrated bioanalytical platform of ADC drugs
In recent years, ADC drugs have gone through multiple iterations to improve efficacy and safety, and have been updated to fourth-generation ADC drugs. ADC drugs' stability, safety, and efficacy require a combination of multiple biological analysis platforms. As more innovative conjugation strategies, antibody scaffolds, and novel warheads are used in next-generation ADCs, bring more challenges to ADC bioanalysis.
Summary
With extensive experience in ADC drug bioanalysis, WuXi AppTec DMPK has established integrated bioanalytical platforms (LBA, LC-MS, LC-HRMS, hybrid LBA/LC-(HR)MS, and QWBA), developed and validated bioanalytical methods to evaluate the components of ADCs, to provide customers with one-stop ADC bioanalysis services. We have supported hundreds of ADC projects, including dozens of ADC IND applications.
DMPK Studies | Pre-clinical Discovery | Pre-clinical Development |
Lead optimization | ADME Characterization and IND application | |
ADME |
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DDI |
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PK |
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Table 4. DMPK studies to support ADC preclinical discovery and development
Committed to accelerating drug discovery and development, we offer a full range of discovery screening, preclinical development, and clinical drug metabolism and pharmacokinetic (DMPK) platforms and services. With research facilities in the United States (New Jersey) and China (Shanghai, Suzhou, Nanjing, and Nantong), 1,000+ scientists, and over fifteen years of experience in Investigational New Drug (IND) application, our DMPK team at WuXi AppTec are serving 1,600+ global clients, and have successfully supported 1,500+ IND applications.
Talk to a WuXi AppTec expert today to get the support you need to achieve your drug development goals.
Authors: Maotian Zhou, Huijuan Qian
Reference
1. Ruan DY, Wu HX, Meng Q, Xu RH. Development of antibody-drug conjugates in cancer: Overview and prospects. Cancer Commun (Lond). 2024 Jan;44(1):3-22. doi: 10.1002/cac2.12517. Epub 2023 Dec 30. PMID: 38159059; PMCID: PMC10794012.
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