Recommendations for the development and validation of flow cytometry-based receptor occupancy assays

Area of Science:

• Biotechnology
• Pharmacology
• Immunology

Background:

• Receptor occupancy (RO) assays measure biotherapeutic binding to extracellular targets.
• RO data complements pharmacokinetic (PK) assessments for PK/PD modeling.
• RO assays are vital for validating dose selection in drug development.

Purpose of the Study:

• Provide technical guidance for developing cytometry-based RO assays.
• Address challenges in RO assay development and validation.
• Ensure accurate pharmacodynamic assessment of biotherapeutics.

Main Methods:

• Discuss considerations for cell and target-bound therapeutic agent stability.
• Highlight challenges in selecting appropriate reagents for RO assays.
• Detail validation strategies for cytometry-based RO assays.

Main Results:

• Identified critical factors for successful RO assay development.
• Provided solutions for reagent competition and affinity issues.
• Established a framework for validating RO assay performance.

Conclusions:

• Cytometry-based RO assays are integral to biotherapeutic development.
• Careful consideration of stability and reagent selection is paramount.
• Validated RO assays enable robust PK/PD modeling and dose selection.