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Biological Activity

Potency is the only critical quality attribute (CQA) that measures the biological activity of a therapeutic, associated with the intended mechanism of action (MOA).
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Potency assay considerations

As defined in ICH guideline Q6B, potency is measured using a suitable quantitative biological assay (also called potency assay or bioassay). A good understanding of the molecule is required to inform the chosen potency assay or assays and should be based on specific attributes that link to the MOA and hence intended efficacy in the patient population. 

The design and development of each assay should be carefully considered and specific for each therapeutic. The scientific rationale for choosing each potency assay must be well documented to support the decision-making pathway. 

  • Where the MOA is straightforward, for example blocking a ligand from binding a receptor, then a single ligand-binding assay (e.g., ELISA) may be suitable 

  • For more complex therapeutics, a gene or cell therapy for example, there may be more than one MOA, or the MOA is poorly understood. It may be more appropriate in such cases to develop a matrix of potency assays to help characterize the intended therapy

  • At least one in vitro cell-based assay will often be required, but other assays may be useful during the characterization phase. Data gathered from a potency matrix will help inform biological attributes more closely associated with clinical efficacy

  • Potency assays that reflect clinical efficacy and are shown to be precise and accurate, able to detect sub-potent batches or changes resulting from degradation events, are then often good candidates as QC release assays as the therapeutic advances through development. Other assays can continue to be used for further characterization or removed if found to be unnecessary

We strongly advise beginning development of the potency assay as early as possible. We provide a defined characterization package with the inclusion of a well-documented potency assay strategy to greatly enhance regulatory approval into the clinic and mitigate costly and time-consuming delay. 

Developing potency assay resources

Article

Potency assays 101: How to develop a CMC relative potency assay

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Info Sheet

Potency Assay Development. Creating Potential. Together.

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