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A novel approach to assess domain specificity of anti-drug antibodies to moxetumomab pasudotox, an immunotoxin with two functional domains.
- Source :
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Journal of immunological methods [J Immunol Methods] 2020 Feb; Vol. 477, pp. 112688. Date of Electronic Publication: 2019 Oct 30. - Publication Year :
- 2020
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Abstract
- Biologics are potentially immunogenic and can elicit immune response. Complex biologics, such as bispecific antibodies or multi-domain molecules can induce anti-drug antibodies (ADA) with specificity to different domains. Domain specific ADAs may differently affect drug efficacy and safety, and thus, characterization of ADA domain specificity has become a regulatory expectation for multi-domain biologics. Unlike well-established methods for screening, confirmation, titer and neutralizing ADA detection, characterization of ADA domain specificity is an emerging field. The conventional approach for determination of ADA domain specificity is a competitive inhibition with domain-containing molecules. When developing a conventional domain specificity assay for moxetumomab pasudotox, a recombinant anti-CD22 immunotoxin, comprised of two functional domains (CD22-binding fragment and truncated Pseudomonas exotoxin A (PE38), we encountered a bioanalytical challenge. The method was able to detect immunodominant anti-PE38 (ADA-PE) but generated false negative results for low abundant CD22-binding domain ADA (ADA-BD) in a polyclonal sample. Troubleshooting experiments using control samples with varying levels of each ADA subtype demonstrated that a major factor for successful ADA identification was the ratio of the ADA signals contributed by each ADA subtype. To overcome this unique bioanalytical challenge, we developed a novel approach, which ensures detection of a domain-specific ADA subtype regardless of its relative level in a polyclonal ADA sample by evaluating signal inhibition by a respective domain-containing molecule at the condition when signals from all other ADAs are fully blocked. The method has been used for characterization of ADA domain specificity in moxetumomab pasudotox clinical trials, including study 1053, the pivotal Phase III study in hairy cell leukemia patients. It allowed for successful detection of ADA-BD in the presence of immunodominant ADA-PE, enabling accurate determination of domain specificity for moxetumomab pasudotox. The results demonstrated that the method was superior than the conventional approach. The method could be applied broadly to other biologics with two or more domains when there is a need to detect a minor ADA subtype in polyclonal samples.<br /> (Copyright © 2019. Published by Elsevier B.V.)
- Subjects :
- ADP Ribose Transferases immunology
Antibodies blood
Antibodies immunology
Bacterial Toxins administration & dosage
Bacterial Toxins adverse effects
Clinical Trials, Phase III as Topic
Exotoxins administration & dosage
Exotoxins adverse effects
False Negative Reactions
Feasibility Studies
Humans
Immunoassay methods
Leukemia, Hairy Cell blood
Leukemia, Hairy Cell immunology
Sensitivity and Specificity
Treatment Outcome
Virulence Factors immunology
Pseudomonas aeruginosa Exotoxin A
Antibodies isolation & purification
Bacterial Toxins immunology
Drug Monitoring methods
Exotoxins immunology
Leukemia, Hairy Cell drug therapy
Protein Domains immunology
Subjects
Details
- Language :
- English
- ISSN :
- 1872-7905
- Volume :
- 477
- Database :
- MEDLINE
- Journal :
- Journal of immunological methods
- Publication Type :
- Academic Journal
- Accession number :
- 31676342
- Full Text :
- https://doi.org/10.1016/j.jim.2019.112688