Skip to main content

<1xxx> Fc Function Assays

Type of Posting: General Chapter Prospectus

Posting Date: 28–Oct–2016

Expert Committee: Biologics Monographs 2—Proteins

Input Deadline: November 28, 2016

Proposed Title: Fc Function Assays

Suggested Audience: Biopharmaceutical industry, regulatory agencies, pharmaceutical scientists, biologists, immunologists, academicians and therapeutic drug manufacturers.

Estimated proposal PF: 44(2) [Mar.–Apr. 2018]

Background and Objectives: This new general information chapter (numbered above 1000) is intended to provide knowledge regarding Fc-Fcγ receptor complexes, Fc mediated effector function of therapeutic antibodies, and assessment of Fc functionality during antibody development and manufacturing. The proposed chapter will focus on selection, development, and validation of suitable Fc assay formats, including the measurement of low affinity interactions observed with FcγR and the impact of glycosylation on antibody effector function. The chapter will discuss development and validation of assays to evaluate the neonatal Fc-Receptor (FcRn) binding, Fc gamma receptor (FcγR) interactions, and complement binding. Additionally, the chapter will include both, the cell based assay formats for antibody dependent cell mediated cytoxicity (ADCC), complement dependent cytotoxicity (CDC), antibody dependent cell mediated phagocytosis (ADCP), and the non-cell based assay formats. The general chapter will complement USP general chapter <129> Analytical Procedures for Recombinant Therapeutic Monoclonal Antibodies.

Preliminary Outline:

  1. Introduction and scope
  2. Definitions
  3. Strategies and factors that influence assay selection
    • Overview of classification – Class I, II, and III based on mechanism of action
    • Risk based assessment
  4. Fc functions
    • i.FcRn mediated functions
      • Assay development and format considerations
      • b.Non cell-based assays
      • Cell-based assays
      • Critical reagent qualification and management
    • Fcγ receptor mediated functions
      • Assay development and format considerations
      • Non cell-based assays
        • Fcγ receptor binding assays
      • Cell-based assays for the functional assessment of FcɣR activities
        • ADCC
        • CDC
        • ADCP
      • Critical reagent characterization, qualification and management
        • E.g. cell lines with different Fcγ receptor allelic variants
  5. Assay lifecycle management
    • Assay validation parameters
    • Assay sensitivity to post translation modifications
    • Role of lot release assay versus characterization assay
    • Interpretation of assay results from the different formats
      • Binding vs cell-based
      • Primary cells vs engineered cell lines

Other USP sources of related information:

  • <129> Analytical Procedures for Recombinant Therapeutic Monoclonal Antibodies
  • <1106.1> Immunogenicity Assays—Design and Validation of Assays to Detect Neutralizing Antibodies
  • <1027> Flow Cytometry
  • <1105> Immunological Test Methods—Surface Plasmon Resonance

Contact: Kamalpreet Arora, Ph.D., (301-816-8287, kta@usp.org).