Potency assays

According to ICH Q6B, potency is the quantitative measure of a product’s biological activity, determined through a validated bioassay that reflects its mechanism of action.

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Measuring the biological activity of your product with confidence

Potency assays, also known as bioassays, are essential throughout the development of biopharmaceutical products. They bridge the gap between a product’s analytical characterisation and its actual biological effect, providing the functional evidence of its efficacy. From early-stage studies to GMP compliant batch release testing, these assays ensure product consistency and integrity over time.

At Quality Assistance, we design, validate and execute potency assays that are tailored to your product’s mode of action and compliant with EMA and FDA expectations, giving you full confidence in your critical analytical decisions.

Analytical challenges we solve

Defining biological potency requires both precision and experience. Each molecule interacts differently with its target, meaning there is no “one-size-fits-all” approach. At Quality Assistance, we help you:

  • Select a relevant model reflecting your product’s mechanism of action
  • Design assays that remain robust despite biological variability
  • Correlate potency with your product quality attributes
  • Choose the appropriate read-out system (binding vs. functional)
  • Validate methods according to international guidelines (ICH Q2(R2), Q14, USP <1033>)
  • Ensure long-term consistency across GMP release and stability testing via method lifecycle management

Our teams apply a pragmatic and phase appropriate Quality by Design (QbD) approach, working collaboratively with you to define the Analytical Target Profile to ensure assay relevance, precision and robustness aligned with your development strategy.

Our approach to potency testing

We provide end-to-end support for potency assay development, from method design to routine use, in full compliance with ICH and USP guidance.

  • Development and optimisation

    • Custom assay design reflecting your product’s mechanism of action
    • Risk-based identification of critical parameters
    • Collaborative definition of assay acceptance criteria
  • Method transfer

    • Transfer from your laboratories or third-party labs under a defined protocol
    • Optimisation of your existing assays within our GMP-compliant environment
    • On-site training for seamless knowledge continuity
  • Validation and routine use

    • Validation under ICH Q2(R2) and USP <1033> for bioassays
    • Preparation of regulatory-compliant protocols and reports
    • Application to GMP batch release and stability testing
    • Statistical trending for continuous performance monitoring

Two complementary approaches: Ligand-Binding and Cell-Based Assays

Because biological activity can be seen from different angles, we combine ligand-binding assays (LBA) and cell-based assays to capture a complete picture of your product’s potency.

Measure how strongly your molecule binds to its biological target, the first step in confirming your product specificity and consistency. They are particularly relevant for monoclonal antibodies, ADCs and vaccines.

  • Platforms: ELISA, SPR/BLI (kinetics/binding assays), Gyrolab™, Luminex® and MSD® (multiplex systems)

Demonstrate the actual biological response (activation, inhibition, cytotoxicity or gene expression) in a living cellular system.

  • Techniques: proliferation/cytotoxicity assays, reporter gene assays, ELISpot/FluoroSpot, Flow cytometry-based assays and qPCR/ddPCR readouts

Technologies and analytical environment

Our potency testing capabilities combine cutting-edge technologies with secure digital data management systems.

From binding kinetics to cell response quantification, all assays are developed under GMP-compliant environment, validated according to ICH and USP guidelines and performed across 4 dedicated in-house laboratories, for a total of 22 workstations.

Download our technical sheet to explore our full capabilities

Technical sheet Potency assays

Why innovators choose Quality Assistance

Partnering with us means working with an analytical CRO that understands your scientific and strategic priorities. What we offer:

  • Comprehensive capacity: dedicated GMP-compliant bioassay labs
  • Integrated expertise: from method development to batch release, on one site
  • Regulatory understanding: assays validated in line with EMA/FDA expectations, compliant with ICH Q2(R2), Q6B, Q14, and USP <1033>
  • Tailored partnership: collaborative assay design aligned with your product’s mode of action
  • Strategic guidance: assays built for comparability, release and stability, with sound performance criteria (ATP)
  • Data integrity: secured systems, full traceability and continuous performance trending

Ready to discuss your potency testing strategy?

Our experts help you define and validate potency assays that accurately reflect your product’s mechanism of action, ensuring regulatory compliance and accelerating your path to patients.

Contact us to start your analytical development process

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