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Precise Quantification of a Therapeutic Monoclonal Antibody Amidst Interference by a Target Molecule in Human Serum

  • 1.  Precise Quantification of a Therapeutic Monoclonal Antibody Amidst Interference by a Target Molecule in Human Serum

    Community Leadership
    Posted 05-23-2025 09:44

    Today, May 23rd, the PK method working group is hosting a team discussion @12:30 pm EST. Below is the agenda and meeting info: 

    Topic: Precise Quantification of a Therapeutic Monoclonal Antibody Amidst Interference by a Target Molecule in Human Serum.- Jin Wang (Amgen)

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    +1 860-785-9696,,877368932#   United States, Hartford

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    Learn More | 19_meeting_NmNiNDEyMWQtMzhlNC00ZTMyLTkzMmMtZGNhZGI2ODQ3OTRi@thread.v2&messageId=0&language=en-US" target="_blank" rel="noopener">Meeting options



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    Mark Ma Ph.D.
    VP. Head of Translational Sciences and Early Development
    Rallybio
    Madison CT

    Disclaimer: Opinions expressed are solely my own and do not express the views or opinions of my employer.
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  • 2.  RE: Precise Quantification of a Therapeutic Monoclonal Antibody Amidst Interference by a Target Molecule in Human Serum

    Posted 06-02-2025 01:33
      |   view attached

    Dear All, here we would like to thank Dr. Jin Wang from Amgen for her nice presentation for AAPS PK methodology discussion group May, 2025 meeting. The presentation title is Precise Quantification of a Therapeutical Monoclonal Antibody Amidst Interference by a Target Molecule in Human Serum. The presentation was also part of WRIB 2025 tutorial. Below is the high-level summary for the presentation. Please see the enclosed slide deck for detailed information.

    • Bivalency of mAbs can lead to complex formation with soluble targets, interfering with quantification of unbound therapeutic antibodies.

    • discussion aspects include total drug measurement, pre-clearing of targets, scavenger agents, and assay optimizations like increasing LLOQ or MRD.

    • Case Study:  Involved an ELISA-based assay for a fully human IgG1 mAb with a target LLOQ of 1.00 ng/mL in human serum.

      • Initial Issue: Signal drop observed during PK assay development, traced to target molecule interference, not drug instability. Target binding to mAb was time- and concentration-dependent, verified via inhibition experiments.

    • Optimization Strategy: 1) Increased MRD, evaluated various buffers, raised LLOQ to 4 ng/mL, and replaced human serum with rabbit serum. 2) Rabbit serum was validated as a suitable surrogate matrix, free from target interference. 3) Human serum was treated with biotinylated anti-target antibodies and streptavidin beads to create target-depleted serum for comparison.

    • Method Validation runs: accuracy, precision, selectivity (in various human sera types), specificity, stability, dilutional linearity, parallelism, and incurred sample reanalysis (ISR). The assay showed inhibition at a 1:1 molar ratio of target to therapeutic mAb, confirming mechanism and validating assay specificity. The mAb remained stable through 4 freeze-thaw cycles and up to 226 days at −20°C or −70°C in both rabbit and human serum.

    •  The validated method, with a quantification range of 4–400 ng/mL, supported a First-in-Human (FIH) clinical study with 39 assay runs. A regulatory-compliant, interference-resistant PK method was successfully developed, enabling precise quantification of therapeutic mAbs in complex biological matrices.



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    Xiaohui Xu Ph.D.
    Director
    Daiichi Sankyo
    Basking Ridge NJ
    [email protected]

    Disclaimer: Opinions expressed are solely my own and do not express the views or opinions of my employer.
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    Attachment(s)

    pptx
    2025 WRIB Presentation_Jin Wang.pptx   2.69 MB 1 version
    Original Message